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The intestinal anti-inflammatory effect of quercitrin is associated with an inhibition in iNOS expression
British Journal of Pharmacology
Abstract
Quercitrin, 3-rhamnosylquercetin, is a bioflavonoid with antioxidant properties, which exerts anti-inflammatory activity in experimental colitis. In the present study, different in vivo experiments were performed in order to evaluate the mechanisms of action involved in this effect, with special attention to its effects on proinflammatory mediators, including nitric oxide (NO).
Experimental colitis was induced in female Wistar rats by incorporation of dextran sodium sulfate (DSS) in drinking water. Oral treatment of quercitrin (1 or 5 mg kg−1 day−1) to colitic rats ameliorated the evolution of the inflammatory process induced when administered in a preventative dosing protocol. When quercitrin (1 mg kg−1 day−1) was administered on established colitis, it facilitated the recovery of the inflamed mucosa.
The beneficial effects exerted by quercitrin were evidenced both histologically and biochemically, and were associated with an improvement in the colonic oxidative status, altered as a consequence of the colonic insult induced by DSS. In addition, a reduction of colonic NO synthase activity was observed, probably related to a decreased expression in the inducible form of the enzyme via downregulation in the colonic activity of the nuclear factor-κB.
Immunohistochemical studies showed that quercitrin treatment reduced macrophage and granulocyte infiltration in the inflamed tissue.
British Journal of Pharmacology (2004) 143, 908–918. doi:10.1038/sj.bjp.0705941
... MCJ-deficient mice on a C57BL/6 background and wild-type B6 mice (8-10 wk) were used under the approval of the Animal Research Ethics Board of CIC bioGUNE (Spain; permit number CBBA-0615). 27 Mice were maintained under specific pathogen-free conditions, applying standard housing conditions (21-23°C temperature and 12/12-h light/dark cycles) and were fed ad libitum on standard mouse chow diet (Global diet 2914, Harlem, Madison, USA). ...
... The criteria proposed by Camuesco et al. were used to assign scores. 27 Weight loss percentage alone is an adequate and sufficient method to assess DSS-induced colitis in mice and it was calculated by dividing the total weight loss throughout the experiment by the initial weight and multiplied by 100. ...
Anti-TNF therapy can induce and maintain a remission status during intestinal bowel disease. However, up to 30% of patients do not respond to this therapy by mechanisms that are unknown. Here, we show that the absence of MCJ, a natural inhibitor of the respiratory chain Complex I, induces gut microbiota changes that are critical determinants of the lack of response in a murine model of DSS-induced inflammation. First, we found that MCJ expression is restricted to macrophages in human colonic tissue. Therefore, we demonstrate by transcriptomic analysis of colon macrophages from DSS-induced mice that MCJ-deficiency is linked to the expression of genes belonging to the FcγR signaling pathway and contains an anti-TNF refractory gene signature identified in ulcerative colitis patients. The gut microbial composition changes observed upon DSS treatment in the MCJ-deficient mice revealed the increased presence of specific colitogenic members, including Ruminococcus gnavus and Oscillospira, which could be associated with the non-response to TNF inhibitors. Further, we show that the presence of a microbiota associated resistance to treatment is dominant and transmissible to responsive individuals. Collectively, our findings underscore the critical role played by macrophage mitochondrial function in the gut ecological niche that can substantially affect not only the severity of inflammation but also the ability to successfully respond to current therapies.
... Taguchi et al., (1993) and Byung et al. (2007) demonstrated that quercitrin has a dose-dependent effect in reducing paw edema induced by carrageenan, dextran, histamine, serotonin and BK, and zymosaninduced paw edema [82,83]. Quercitrin is widely reported for its actions directly impacting the production of cytokines in the inflammatory process [84], reducing inflammatory cells [85], and inhibiting the nuclear factor kappa B (NF-kB) pathway and consequently the production of NO [86]. The inhibition of cytokines such as IL-1β, TNF-α, IL-6 by caffeic acid [87][88][89][90][91][92], quercetin [85,[93][94][95][96] and gallic acid [97] can be related to the activities presented. ...
... Also suggest that prostaglandin E2 could be a regulating factor involved in cytokine production at the inflammatory site by increase in nuclear factor-κB DNA binding activity paralleled both exudate formation and leukocyte infiltration [137]. These results corroborate data from the literature on the chemical constituents present in the extract of X. americana that had a direct effect on the production of cytokines, inhibiting the actions of IL-1β and TNF-α, effects that may be related to the presence of acid caffeic acid, quercetin, quercetin and gallic acid [86][87][88][89][90][91][92][93][94][95][96][97]. ...
Edema is one of the obvious indicators of inflammation and a crucial factor to take into account when assessing a substance's capacity to reduce inflammation. We aimed to evaluate the antiedematogenic and anti-inflammatory profile of the hydroethanolic barks extract of Ximenia americana (HEXA). The possible antiedematogenic and anti-inflammatory effect of EHXA (50, 100 mg/kg and 250 mg/kg v.o) was evaluated using the paw edema induced by carrageenan, zymosan, dextran, CFA and by different agents inflammatory (serotonin, histamine, arachidonic acid and PGE 2), and pleurisy model induced by carrageenan and its action on IL-1β and TNF-α levels was also evaluated. HEXA demonstrated a significant antiedematogenic effect at concentrations of 50, 100 and 250 mg/kg on paw edema induced by carrageenan, zymosan and dextran. However, the concentration of 50 mg/ kg as standard, demonstrating the effect in the subchronic model, induced CFA with inhibition of 59.06 %. In models of histamine-induced paw edema, HEXA showed inhibition of − 30 min: 40.49 %, 60 min: 44.70 % and 90 min: 48.98 %; serotonin inhibition-30 min: 57.09 %, 60 min: 66.04 % and 90 min: 61.79 %; arachidonic acid inhibition-15 min: 36.54 %, 30 min: 51.10 %, 45 min: 50.32 % and 60 min: 76.17 %; and PGE 2 inhibition-15 min: 67.78 %, 30 min: 62.30 %, 45 min: 54.25 % and 60 min: 47.92 %. HEXA significantly reduced (p < 0.01) leukocyte migration in the pleurisy model and reduced TNF-α and IL-1β levels in pleural lavage (p < 0.0001). The results showed that HEXA has the potential to have an antiedematogenic impact in both acute and chronic inflammation processes, with a putative mode of action including the suppression or regulation of inflammatory mediators. * Corresponding authors.
... Subsequently, through the action of superoxide anions, excessive NO causes overproduction of peroxynitrites, leading to intestinal destruction [44]. Recent research has shown that flavonoids can inhibit the expression of iNOS, resulting in an apparent reduction in NO production [45]. For the above reasons, flavonoids are able to reduce the enterotoxicity induced by NO. ...
... Some in vivo studies have shown that flavonoids have an anti-inflammatory function by suppressing macrophage activity. For example, Camuesco et al. established murine colitis models induced by DSS and found that quercitrin significantly inhibited macrophage infiltration in the affected colon [45]. In addition, neutrophil infiltration normally occurs in the inflamed bowel of IBD patients. ...
Inflammatory bowel disease (IBD) is a group of disorders that cause chronic non-specific inflammation in the gastrointestinal (GI) tract, primarily affecting the ileum and colon. The incidence of IBD has risen sharply in recent years. Despite continuous research efforts over the past decades, the aetiology of IBD is still not fully understood and only a limited number of drugs are available for its treatment. Flavonoids, a ubiquitous class of natural chemicals found in plants, have been widely used in the prevention and treatment of IBD. However, their therapeutic efficacy is unsatisfactory due to poor solubility, instability, rapid metabolism, and rapid systemic elimination. With the development of nanomedicine, nanocarriers can efficiently encapsulate various flavonoids and subsequently form nanoparticles (NPs), which greatly improves the stability and bioavailability of flavonoids. Recently, progress has also been made in the methodology of biodegradable polymers that can be used to fabricate NPs. As a result, NPs can significantly enhance the preventive or therapeutic effects of flavonoids on IBD. In this review, we aim to evaluate the therapeutic effect of flavonoid NPs on IBD. Furthermore, we discuss possible challenges and future perspectives.
... The heart and lung changes which was observed by TAA treatment could be a consequence of oxidative stress. Prakasam et al. [33] stated that this oxidative stress results from the increased production of reactive oxygen species ROS, which have been shown to damage many biological molecules and causing lipid peroxidation [33] . ...
... The heart and lung changes which was observed by TAA treatment could be a consequence of oxidative stress. Prakasam et al. [33] stated that this oxidative stress results from the increased production of reactive oxygen species ROS, which have been shown to damage many biological molecules and causing lipid peroxidation [33] . ...
... After interacting with the superoxide anions, excessive NO generates an enormous amount of peroxynitrites, which contribute to the intestinal damage [31]. Extensive research has shown that flavonoids can exercise lots of influence on NO metabolism [32], such as the inhibition of the expression of iNOS [33]. As a consequence, flavonoids are able to mitigate the enterotoxicity of NO, which is excessively produced during intestinal inflammation. ...
... Additionally, in vivo studies have also uncovered that flavonoids have anti-inflammation properties. For instance, it was reported by Camuesco et al. [33] that quercitrin remarkably decreased the amount of macrophages infiltrated in the inflamed murine colon induced by DSS. Furthermore, one of the main pathological events in IBD patients is neutrophil infiltration [26]. ...
Inflammatory bowel disease (IBD) is a comprehensive term for chronic or relapsing inflammatory diseases occurring in the intestinal tract, generally including Crohn’s disease (CD) and ulcerative colitis (UC). Presently, the pathogenesis of IBD is unknown, yet multiple factors have been reported to be related with the development of IBD. Flavonoids are phytochemicals with biological activity, which are ubiquitously distributed in edible plants, such as fruits and vegetables. Recent studies have demonstrated impressively that flavonoids have anti-IBD effects through multiple mechanisms. These include anti-inflammatory and antioxidant actions; the preservation of the epithelial barrier integrity, the intestinal immunomodulatory property, and the shaping microbiota composition and function. In addition, a few studies have shown the impact of flavonoids on enterohormones release; nonetheless, there is hardly any work showing the link between flavonoids, enterohormones release and IBD. So far, the interaction between flavonoids, enterohormones and IBD is elucidated for the first time in this review. Furthermore, the inference can be drawn that flavonoids may protect against IBD through modulating enterohormones, such as glucagon-like peptide 1 (GLP-1), GLP-2, dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors), ghrelin and cholecystokinin (CCK). In conclusion, this manuscript explores a possible mechanism of flavonoids protecting against IBD.
... Hansen et al. [301] , Markham et al. [302] and Hilbert et al. [266] confirming the assigned structure. Quercetin-3-O--L-rhamnoside has been identified in a number of floral species such as edible lotus Nelumbo nucifera [290] , Loranthus regularis [291] , Toona sinesis [296] , Rosa laevigata [303] , Meuhlenbeckia platyclade [304] but has mainly been studied for its potential antioxidant activity [290,291,296,303,305] , anti-inflammatory activity [291,[303][304][305][306] , and for other human health benefits including the inhibition of influenza [169] , the treatment of ischemic stroke [303] and liver protection [290] . Studies by Afifi et al. [295] , and Markham and Viotto [307] have identified quercetin-3-O-α-L-rhamnoside in Myriophyllum spiciatum and the aquatic fern genus Pilularia aquatic flora including aquatic macrophytes and not on the impact to aquatic fauna. ...
... Hansen et al. [301] , Markham et al. [302] and Hilbert et al. [266] confirming the assigned structure. Quercetin-3-O--L-rhamnoside has been identified in a number of floral species such as edible lotus Nelumbo nucifera [290] , Loranthus regularis [291] , Toona sinesis [296] , Rosa laevigata [303] , Meuhlenbeckia platyclade [304] but has mainly been studied for its potential antioxidant activity [290,291,296,303,305] , anti-inflammatory activity [291,[303][304][305][306] , and for other human health benefits including the inhibition of influenza [169] , the treatment of ischemic stroke [303] and liver protection [290] . Studies by Afifi et al. [295] , and Markham and Viotto [307] have identified quercetin-3-O-α-L-rhamnoside in Myriophyllum spiciatum and the aquatic fern genus Pilularia aquatic flora including aquatic macrophytes and not on the impact to aquatic fauna. ...
Pheromones, semiochemicals that trigger a natural response in a second member of the same species, have been extensively investigated across a variety of vertebrates and invertebrates to manipulate their behaviour. In aquatic species, these pheromones play important roles in larval settlement and metamorphosis, courtship and mating, and foraging. Pheromones responsible for the initiation of mating behaviour in carp and goldfish have been investigated extensively in sexually mature carp but there has been limited investigation on the role the environment plays on behaviour. The introduction of environmental stimuli was investigated to test the hypothesis that environmental cues can be used, like pheromones, to manipulate carp behaviour. Ceratophyllum demersum and Myriophyllum spicatum, a native and invasive aquatic macrophyte, were placed in bioassay tanks with sexually mature carp and spawning incidences recorded across a 15 min monitoring period. A clear preference for the invasive M. spicatum over the native C. demersum was observed even in the presence of yarn used as control. Crude extracts of each plant were tested using yarn as the spawning substrate with similar observations made removing the impact of the physical characteristics to the observed preference. Crude extracts of seven aquatic macrophytes collected from wetlands around Victoria where carp aggregations have been observed (Myriophyllum aquaticum, Egeria densa, Potamogeton crispus. Vallisneria australis, Cabomba caroliniana, Potamogeton sulcatus, and Chara australis) were used in behavioural bioassays mimicking those used for spawning activity to determine if juvenile carp exhibit a behavioural modification in the presence of one of these species. M. aquaticum exhibited the most significant and consistent change to preference and was selected for isolation and purification of potential attractants. In total twelve compounds were isolated and structurally identified using 1D and 2D NMR, mass spectrometry and optical rotation data. Each compound was assessed to determine the preference of juvenile carp. Eight of the twelve compounds tested resulted in a positive behavioural change and provides strong evidence that compounds derived from aquatic flora can potentially be used to manipulate carp behaviour. A final study looking at water collected from known carp aggregation hot spots at Lake Sorell in Tasmania and the Banrock Station wetlands in South Australia was conducted to see if leachates, from the surrounding environment or plants in the water, can result in similar observations. Water collected from the Silver Plains marsh at lake Sorell and the wetland outlet at Banrock station resulted in the most substantial change in carp behaviour. This observation was supported by tracking data of radio-tagged carp obtained during the periods of water collection. While no compounds were able to be successfully isolated from these samples there is potential for future work using water from the wetlands to manipulate carp behaviour. The potential to use environmental attractants to manipulate carp preferences to controlled aggregation sites, or for juvenile aggregation prior to reaching sexual maturity will contribute as part of a broad pest management program assisting in the eradication of carp in our waterways.
... Kwon et al. (2005) failed to observe beneficial effects in the dextran sulphate sodium (DSS) model of mouse colitis while more recent studies have reported intestinal antiinflammatory effects of quercetin in the same experimental model (Dong et al., 2020;Ju et al., 2018). However, quercetin glycosides, including quercitrin or rutin, have shown intestinal anti-inflammatory properties in various experimental models of colitis (Camuesco et al., 2004;Comalada et al., 2005;Kwon et al., 2005), being their effects attributed to quercetin, which is released after hydrolysis in the colon (Comalada et al., 2005). ...
... Unfortunately, this therapeutic potential is conditioned by its low bioavailability after oral intake, due to low solubility and stability, being this is of special relevance in intestinal conditions, like IBD (Cai et al., 2013). In fact, previous preclinical studies have proposed that quercetin needs to be administered as a glycoside, like quercitrin or rutin, to show intestinal anti-inflammatory effects (Camuesco et al., 2004;Comalada et al., 2005;Kwon et al., 2005;Mascaraque et al., 2014). In an attempt to overcome these limitations, several strategies have been considered. ...
Inflammatory bowel disease (IBD) is a chronic and idiopathic inflammatory disorder affecting the gastrointestinal tract. The pharmacological treatments used currently for its treatment lack efficacy, so new therapeutic strategies should be developed. In this context, flavonoids loaded in biopolymeric nanoparticles can be considered as novel promising candidates. The aim of the present study was to evaluate the intestinal anti-inflammatory effects of quercetin when is administered loaded in silk fibroin nanoparticles (QSFN) in the dextran sulphate sodium experimental model of mouse colitis, which displays some similarities to human IBD. Previously characterized quercetin-loaded silk fibroin nanoparticles (QSFN). QSFN showed a reversible aggregation profile induced by the acidification of the solution but did not affect the loaded quercetin. Daily administration of QSFN significantly reduced disease activity index values compared to the control colitic group. This beneficial effect was not only corroborated by the histological examination of the colonic specimens but also the improvement of the colonic expression of the different proinflammatory cytokines (Tnf-α, Il-1β, Il-6, Mcp-1, Icam-1, Nlrp3 and iNOS). Therefore, these data suggest that QSFN could be a promising alternative to current treatments as a drug delivery system for IBD treatment.
... Mice were tested daily for body weight, gross rectal bleeding, and stool consistency to assess the extent of UC. Disease activity index (DAI) score was computed to quantify disease severity, as previously described (9,10). ...
... The kinetics of the release of quercitrin and myricitrin were marked by a rapid release into the decoction, perhaps because they are easily extracted at boiling temperature. Although the biological effects of glycosylated flavonoids are complex, it appears that both myricitrin and quercitrin can scavenge free radicals generated through oxidative stress and thus decrease inflammation [39,40]. Quercitrin also inhibits anti-cholinergic esterase activity that may be beneficial in the treatment of kidney stones by promoting urinary tract smooth muscle relaxation and passage of a kidney stone [41]. ...
Bryophyllum pinnatum (BP) is a medicinal plant used to treat many conditions when taken as a leaf juice, leaves in capsules, as an ethanolic extract, and as herbal tea. These preparations have been chemically analyzed except for decoctions derived from boiled green leaves. In preparation for a clinical trial to validate BP tea as a treatment for kidney stones, we used NMR and MS analyses to characterize the saturation kinetics of the release of metabolites. During boiling of the leaves, (a) the pH decreased to 4.8 within 14 min and then stabilized; (b) regarding organic acids, citric and malic acid were released with maximum release time (tmax) = 35 min; (c) for glycoflavonoids, quercetin 3-O-α-L-arabinopyranosyl-(1 → 2)-α-L-rhamnopyranoside (Q-3O-ArRh), myricetin 3-O-α-L-arabinopyranosyl-(1 → 2)-α-L-rhamnopyranoside (M-3O-ArRh), kappinatoside, myricitrin, and quercitrin were released with tmax = 5–10 min; and (d) the total phenolic content (TPC) and the total antioxidant capacity (TAC) reached a tmax at 55 min and 61 min, respectively. In summary, 24 g of leaves boiled in 250 mL of water for 61 min ensures a maximal release of key water-soluble metabolites, including organic acids and flavonoids. These metabolites are beneficial for treating kidney stones because they target oxidative stress and inflammation and inhibit stone formation.
... Subsequently, 41 core constituents were screened out by NP, which included 13 quinones, 10 flavonoids, 5 terpenoids, 4 phenols, 3 alkaloids, 2 phenylpropanoids, 1 organic acid, 1 aldehyde and 2 miscellaneous compounds, and mainly from MOC, SMR and RRR. The previous studies found that flavonoids (such as quercitrin) were suggested to have iNOS inhibition to inhibit the excessive production of NO during intestinal inflammation and mitigate the enterotoxicity [47,48]. In addition, extensive research has shown that honokiol (70) could inhibit the mRNA expression of iNOS and proinflammatory cytokines. ...
Background
Postoperative ileus (POI) is a common obstruction of intestinal content passage caused by almost all abdominal operations that seriously strokes the quality of life of patients. Kuanchang-Shu granule (KCSG), a classic modified prescription based on “Da-Cheng-Qi Decoction”, has obtained satisfactory efficacy in the clinical therapeutics of POI. However, its material basis and holistic molecular mechanism against POI have not been revealed.
Methods
The chemical ingredients of KCSG were first characterized by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). Subsequently, an integration strategy of the network pharmacology and molecular docking based on above identified ingredients was performed to unveil the potential targets involved in the treatment of KCSG on POI. Finally, intestinal manipulation induced rat POI model was constructed to verify the efficacy and predicted mechanism of KCSG against POI.
Results
In total, 246 ingredients mainly including organic acids, flavonoids, quinones, alkaloids, terpenoids, phenylpropanoids and phenols were identified. 41 essential ingredients, 24 crucial targets as well as 15 relevant signaling pathways were acquired based on network pharmacology analysis. Pharmacodynamic research showed that KCSG treatment could protect intestinal histological damage, promote the recovery of measurement of gastrointestinal transit disorder and inhibit the secretion of myeloperoxidase in the distal ileum tissues. The up-regulated expression of p-AKT and down-regulated expression of p-eNOS and HSP9OAA1 predicted by molecular docking and validated by western blotting showed that AKT/eNOS/HSP90AA1 pathway may be one of the crucial mechanisms that mediates the protective effect of KCSG.
... Similarly, caffeic acid derivatives can scavenge nitric oxide as well as modulate iNOS expression [41], while flavonoids can inhibit transcription factors or regulatory enzymes essential for controlling inflammatory mediators. Regarding the latter, previous studies have reported that flavonoids such as quercitrin, rutin, glabridin, naringenin, chrysin, and cardamonin can reduce the severity of experimental-induced colitis and ameliorate the histological damage by reducing cytokine release in the colonic tissue [44][45][46]. Some of the mechanisms proposed to support these beneficial effects have been related to its ability to inhibit cellular pathways, including nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), and STAT activation [47][48][49], which actively contribute to the pathology of these intestinal conditions [50,51]. ...
Inflammatory bowel disease (IBD) is a chronic gastrointestinal inflammation with unpredictable symptom fluctuations. While there is no effective cure for IBD, various treatments aim to manage symptoms and improve the quality of life for affected individuals. In recent years, there has been growing interest in the potential benefits of certain natural plants and herbs in the management of IBD. In this regard, this study aimed to evaluate the immunomodulatory and anti-inflammatory effects of a well-characterized extract of Salvia verbenaca (S. verbenaca) in an experimental model of colitis in rats. Interestingly, the daily administration of S. verbenaca (10 and 25 mg/kg) effectively alleviated colitis symptoms, as evidenced by reduced weight/length ratio and colonic damage. Moreover, it reduced oxidative stress markers (MPO and GSH), decreased pro-inflammatory cytokine expression (Il-6, Il-12a, Il-1β, Il-23, Icam-1, Mcp-1, Cinc-1), and preserved the integrity of the intestinal barrier (Villin, Muc-2, Muc-3). These effects suggest S. verbenaca extract could represent a potential complementary candidate to treat gastrointestinal disorders. Its beneficial actions can be related to its antioxidant properties as well as the downregulation of the immune response, which can result in the improvement in the intestine epithelial barrier.
... 52 On the other hand, specific iNOS inhibition activity was observed in whole-leaf extracts of 100-year-old trees and acetone leaf extracts from 30-year-old trees attributable to the effectiveness of quercitrin and skutellarein. 53,54 All other extracts showed significant cytotoxic effects on RAW 264.7 cells, even though they showed iNOS activity (Table 4). In this study, the antiviral activity of selected mastic gum samples was performed for the first time against IBV D274 (Table 5) (Fig. 3). ...
BACKGROUND
Mastic gum is a resin that is produced by Pistacia lentiscus. It has many traditional uses, dating from ancient times, such as the treatment of gastrointestinal disorders and as a food additive. In this study, the leaves and mastic gum of trees of different ages from Karaburun and the Cesme peninsula in Türkiye were examined chemically and biologically. Flavonoids, and phenolic and fatty acid components were evaluated by a liquid chromatography system coupled with high resolution mass spectrometry (LC‐HRMS) and gas chromatography with flame ionization detection (GC‐FID). Cytotoxicity was screened against several cancer and healthy cell lines using a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) assay. Inducible nitric oxide synthase (iNOS) inhibition was determined on lipopolysaccharide (LPS)‐induced murine macrophage cell line (RAW 264.7) cells. Antiviral activity was measured against avian coronavirus using an in ovo virucidal antiviral activity assay.
RESULTS
The main phenolic constituents of the gum were found to be salicylic, rosmarinic, and caffeic acids whereas the most abundant compounds detected were flavonoids in the leaf extracts. The most abundant fatty acids in hexane extracts were palmitic and oleic acids. All gum extracts except 3‐year‐old gum had significant cytotoxic activity on HeLa (IC50 1.74 ± 0.03–4.76 ± 0.95) and PC‐3 (0.64 ± 0.25–6.22 ± 1.40) cells. Moreover, reducing virus activity by fivefold or sixfold logarithmically between the range of 5–10 μg g⁻¹ of 30‐year‐old gum extracts underscored the biological activity.
CONCLUSION
In ovo antiviral activity studies on the P. lentiscus were conducted for the first time. The mastic gum and leaves obtained from P. lentiscus may have strong potential in terms of their chemical content and antiviral and cytotoxic activity. As a consequence of these properties, it is a sustainable, renewable natural resource that can be used as an additive and flavoring in the food and pharmaceutical industries. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
... This index is a score based on animal body weight loss, the presence of blood in feces, and stool consistency. The criteria proposed by Camuesco et al., 2004 were used to assign scores 37 . ...
Recent evidence demonstrates potential links between mitochondrial dysfunction and inflammatory bowel diseases (IBD). In addition, bidirectional interactions between the intestinal microbiota and host mitochondria may modulate intestinal inflammation. We observed previously that mice deficient in the mitochondrial protein MCJ (Methylation-controlled J protein) exhibit increased susceptibility to DSS colitis. However, it is unclear whether this phenotype is primarily driven by MCJ −/− associated gut microbiota dysbiosis or by direct effects of MCJ-deficiency. Here, we demonstrate that fecal microbiota transplantation (FMT) from MCJ-deficient into germ-free mice was sufficient to confer increased susceptibility to colitis. Therefore, an FMT experiment by cohousing was designed to alter MCJ-deficient microbiota. The phenotype resulting from complex I deficiency was reverted by FMT. In addition, we determined the protein expression pathways impacted by MCJ deficiency, providing insight into the pathophysiology of IBD. Further, we used magnetic activated cell sorting (MACS) and 16S rRNA gene sequencing to characterize taxa-specific coating of the intestinal microbiota with Immunoglobulin A (IgA-SEQ) in MCJ-deficient mice. We show that high IgA coating of fecal bacteria observed in MCJ-deficient mice play a potential role in disease progression. This study allowed us to identify potential microbial signatures in feces associated with complex I deficiency and disease progression. This research highlights the importance of finding microbial biomarkers, which might serve as predictors, permitting the stratification of ulcerative colitis (UC) patients into distinct clinical entities of the UC spectrum.
... To analyze the intestinal microbiota using 16S rRNA gene sequencing, feces were collected from the mice on day 14, and colonic tissue was harvested from the mice following euthanasia ( Figure 1). DAI was scored as earlier described (Supplementary Table S1; Murthy et al., 1993;Camuesco et al., 2004). After completion of the treatment, all animals were first anesthetized with sodium pentobarbital (5%), and then sacrificed by cervical dislocation immediately before dissection. ...
Inflammatory bowel disease (IBD) is a serious global public health concern. Although the pathogenesis of the disease is currently unknown, it has been reported to be associated with both intestinal microbiota and inflammatory mediators. There is evidence suggesting that the feces of the Plateau pika is useful for treating gastrointestinal injuries and pain. Although fecal microbiota transplantation is highly efficacious intervention for IBD prevention, however, potential the transfer of pathogenic microbes or toxic substances is potentially hazardous. Fortunately, micropore filtering of the donor feces can minimize the risk of bacterial infection allowing retention of the therapeutic effects of the residual bacteriophages. Here, we demonstrated that Plateau pika feces not only alleviated the IBD symptoms but also promoted optimal structure and composition of the intestinal microbiota. Additionally, Plateau pika feces transfer also enhanced phenotypic features, such as, body-weight, disease activity index, and histological scores. In conclusion, Plateau pika feces was found to protect mice against colitis induced by dextran sodium sulfate by reducing inflammation and regulating microbial dysbiosis. These findings suggest the potential of Plateau pika feces as an alternative therapy for IBD.
... Quercetin, a plant-derived flavonoid, has been reported to exhibit a wide range of biological functions such as antioxidant, antimutagenic, anti-inflammatory and anticarcinogenic properties (Camuesco et al., 2004;Moskaug et al., 2005). Quercetin treatment also induced the activation of Nrf2 signaling pathway and increased Nrf2-mediated transcription activity (Tanigawa et al., 2007). ...
The presence of deoxynivalenol (DON), one of the most frequently occurring mycotoxin, in food and feed has been considered a risk factor to both human and animal health. Molecular mechanisms that regulate DON effects in tissues are still poorly understood. However, recent evidence suggests that nuclear factor erythroid 2-like 2 (Nrf2) may be a major target during mycotoxin-induced intestinal barrier dysfunction. Although quercetin, a plant-derived flavonoid, is known to induce the activation of Nrf2 signaling pathway, its potential to mitigate effects of DON and the implication of Nrf2 in its physiological effects is poorly understood. Therefore, this study was conducted to investigate the protective effects of quercetin in alleviating the DON-induced barrier loss and intestinal injuries in IPEC-J2 cells and weaned piglets and determine the potential role of Nrf2. Quercetin treatment dose-dependently increased mRNA expression of Nrf2 target gene, NQO-1, and concomitantly increased the expression of claudin-4 at both mRNA and protein levels. Quercetin supplementation also reversed the reduction of claudin-4 caused by DON exposure in vivo and in vitro. The decreased membrane presence of claudin-4 and ZO-1 induced by DON was also blocked by quercetin. Furthermore, quercetin attenuated the endocytosis and degradation of claudin-4 caused by DON exposure. The effects of quercetin also included the restoration of transepithelial electrical resistance (TEER) and reduction of FITC-dextran permeability that have been perturbed by DON. However, the protective effects of quercetin against DON exposure were abolished by a specific Nrf2 inhibitor (brusatol), confirming the importance of Nrf2 in the regulation of TJP expression and barrier function by quercetin. In vivo study in weaned pigs showed that DON exposure impaired villus-crypt morphology as indicated by diffuse apical villus necrosis, villus atrophy and fusion. Notably, intestinal injuries caused by DON administration were partly mitigated by quercetin supplementation. Collectively, this study shows that quercetin could be used to prevent the DON-induced gut barrier dysfunction in humans and animals and the protective effects of quercetin against DON-induced intestinal barrier disruption is partly through Nrf2-dependent signaling pathway.
... In this study, H&E-stained sections of subgroup IIC showed preservation of the intestinal architecture of closely packed tubular glands embedded in the lamina propria, normal goblet cells number and size, minimal epithelial damage, and mild inflammatory cell infiltration in lamina propria, being similar to the findings of previous studies [32,33]. There was an increase in submucosal thickness with dilated congested blood vessels, as explained in Ju et al. and Soliman et al. [34,35]. ...
... Oral administration of 1 or 5 mg/kg/day [189] Quercetin reduced MPO activity, TNF-α and IL-1β expression, iNOS, and reduced NF-κB activation in rats with colitis. ...
The Yucca genus encompasses about 50 species native to North America. Species within the Yucca genus have been used in traditional medicine to treat pathologies related to inflammation. Despite its historical use and the popular notion of its antioxidant and anti-inflammatory properties, there is a limited amount of research on this genus. To better understand these properties, this work aimed to analyze phytochemical composition through documentary research. This will provide a better understanding of the molecules and the mechanisms of action that confer such antioxidant and anti-inflammatory properties. About 92 phytochemicals present within the genus have reported antioxidant or anti-inflammatory effects. It has been suggested that the antioxidant and anti-inflammatory properties are mainly generated through its free radical scavenging activity, the inhibition of arachidonic acid metabolism, the decrease in TNF-α (Tumor necrosis factor-α), IL-6 (Interleukin-6), iNOS (Inducible nitric oxide synthase), and IL-1β (Interleukin 1β) concentration, the increase of GPx (Glutathione peroxidase), CAT (Catalase), and SOD (Superoxide dismutase) concentration, and the inhibition of the MAPK (Mitogen-Activated Protein Kinase), and NF-κB (Nuclear factor kappa B), and the activation of the Nrf2 (Nuclear factor erythroid 2–related factor) signaling pathway. These studies provide evidence of its use in traditional medicine against pathologies related to inflammation. However, more models and studies are needed to properly understand the activity of most plants within the genus, its potency, and the feasibility of its use to help manage or treat chronic inflammation.
... The rate of quercetin in the aerial parts of the plant (0.65 μg GAE /mg extract) was in agreement with that reported by Macheix et al. (2005). Quercetin is well known to be among the most active flavonoids, characterized mainly by its strong antioxidant ability (Camuesco et al., 2004;Comalada et al., 2005). It has additionally been reported that this key member of the flavonoids family is considered to be a potent anticarcinogenic and antiinflammatory agent with well-characterized activities in the intestine, lungs, breasts, prostate and liver (Khurana et al., 2013;Khan et al., 2016;Elumalai and Lakshmi, 2016). ...
The aim of this work was to evaluate the effect of Thymus vulgaris L phenolic extracts (TVPE) on the growth of Streptococcus thermophilus and Lactobacil-lus delbrueckii subsp. bulgaricus, and the impact of their addition in small amounts (2-8%) to a set-style yogurt with regard to variations in physico-chemical, bacteria count and organoleptic properties during 21 days storage at 4°C. The phenolic components were extracted from the crushed aerial parts of the test plant by cold maceration in hydro-methanolic solution (methanol: water, 80:20 v/v). The plant polyphenolic profile was determined by HPLC. The survival ability of yogurt starter cultures in the presence of TVPE was evaluated through the determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The total phenolic content (TPC) was 20.2 ± 0.57 μg GAE / mg extract. The amount of flavonoid compounds was 39.83 μg EQ/mg extract. As the quantitative measurements revealed, apigenin and fisetin (8.17, 6.83, μg GAE /mg extract respectively) emerged as major phenolic compounds from thyme aerial parts. The MIC and MBC against the growth of both lactic bacteria were obtained at 60% of TVPE concentration. A significant (p< 0.01) changes in pH, titrable acidity and apparent viscosity were observed in all experimental yogurts. The best scores of sensory evaluation were recorded in samples added with 2% and 4% of TVPE as well as the control. Based on collected data, 2% and 4% of TVPE can be incorporated into yogurt without risk of deterioration in physicochemical quality or inhibition of lactic bacteria.
... However, there are few studies on the immune barrier damage. The disruption of the intestinal mucosal barrier caused by intestinal IRI will ultimately result in the passage of viable bacteria and endotoxins from the gastrointestinal tract to mesenteric lymph nodes complex and distant organs, named as "bacterial translocation" (Camuesco et al., 2004), which may aggravate local injury and cause impaired function of remote organs by initiating inflammatory responses and subsequent immunosuppression (Leaphart, Tepas 3 rd , 2007). ...
Abstract Intestinal ischemia/reperfusion (I/R) causes barrier impairment and bacterial influx. This study explored the protective effects of anisodamine hydrobromide (AH) on intestinal I/R injury caused by cardiopulmonary resuscitation (CPR) after cardiac arrest (CA). After successful CPR, minipigs were randomly divided into two groups (n = 8): saline and AH (4 mg/kg), and then treated with saline or AH via central venous injection, respectively. The same procedures without ventricular fibrillation initiation were conducted in the Sham group (n = 8). Levels of interferon gamma (IFN-γ) and interleukin 4 (IL-4) were measured at different time points (0, 0.5, 1, 2, 4, and 6 h) in serum and 6 h in gut associated lymphoid tissues (GALTs) after the return of spontaneous circulation (ROSC) to evaluate changes in the proportion of T-helper type 1 (Th1) and T-helper type 2 (Th2). Moreover, the positive culture rates of GALTs were examined to evaluate bacterial translocation. AH treatment markedly alleviated aberrant arterial blood gas and hemodynamics as well as intestinal macroscopic and morphological changes after CPR. Moreover, AH treatment significantly increased IFN-γ and decreased IL-4 in both serum and GALTs. Furthermore, AH treatment dramatically decreased positive bacterial growth in GALTs. AH treatment mitigated immunosuppression caused by intestinal I/R and protected the intestinal immune barrier against bacterial translocation, thereby reducing the risk of secondary intestinal infection.
... Quinic acid is the key component of chlorogenic acids, one of the most abundant phenolic acids in the plant kingdom [28]. Quercitrin (quercetin-O-rhamnoside) is a flavonoid found in many vegetables and Hypericum species [29], and it exhibits various bioactive properties, such as cytotoxicity, antioxidative activity, anti-inflammatory activity, and antiallergic activity [30][31][32]. Moreover, quercitrin has been known to inhibit the cell death or apoptosis induced by ultraviolet (UV) light [33,34]. ...
Nanospray desorption electrospray ionization (nano-DESI) is one of the ambient desorption ionization methods for mass spectrometry (MS), and it utilizes a steady-state liquid junction formed between two microcapillaries to directly extract analytes from sample surfaces with minimal sample damage. In this study, we employed nano-DESI MS to perform a metabolite fingerprinting analysis directly from a Hypericum leaf surface. Moreover, we investigated whether changes in metabolite fingerprints with time can be related to metabolite distribution according to depth. From a raw Hypericum leaf, the mass spectral fingerprints of key metabolites, including flavonoids and prenylated phloroglucinols, were successfully obtained using ethanol as a nano-DESI solvent, and the changes in their intensities were observed with time via full mass scan experiments. In addition, the differential extraction patterns of the obtained mass spectral fingerprints were clearly visualized over time through selected ion monitoring and pseudo-selected reaction monitoring experiments. To examine the correlation between the time-dependent changes in the metabolite fingerprints and depth-wise metabolite distribution, we performed a nano-DESI MS analysis against leaves whose surface layers were removed multiple times by forming polymeric gum Arabic films on their surfaces, followed by detaching. The preliminary results showed that the changes in the metabolite fingerprints according to the number of peelings showed a similar pattern with those obtained from the raw leaves over time.
... Similarly, the use of natural antioxidants such as Garcinia Kola nuts was able to decrease the symptom severity of colitis in mice [61]. In addition, DSS-induced weight loss and histopathological alterations were significantly restored by flavonoid treatment [62][63][64]. FC is a pro-inflammatory protein, and it plays a significant role in sites of inflammation by triggering the toll-like receptors [65]. ...
Oxidative stress is considered the main etiologic factor involved in inflammatory bowel disease (IBD). Integration of nanocarriers for natural therapeutic agents with antioxidant and anti-inflammatory potential is a novel promising candidate for curing IBD. Herein, the colonic antioxidant and anti-inflammatory effects of different concentrations of quercetin nanoparticles (QT-NPs) were evaluated using a dextran sulfate sodium (DSS)-induced colitis model. Following colitis induction, the efficacy and mechanistic actions of QT-NPs were evaluated by assessing lesion severity, molecular aids controlling oxidative stress and inflammatory response, and histopathological and immunohistochemistry examination of colonic tissues. Administration of QT-NPs, especially at higher concentrations, significantly reduced the disease activity index and values of fecal calprotectin marker compared to the colitic group. Colonic oxidant/antioxidant status (ROS, H2O2, MDA, SOD, CAT, GPX and TAC) was restored after treatment with higher concentrations of QT-NPs. Moreover, QT-NPs at levels of 20 mg/kg and, to a lesser extent, 15 mg/kg reduced Nrf2 and HO-1 gene expression, which was in line with decreasing the expression of iNOS and COX2 in colonic tissues. Higher concentrations of QT-NPs greatly downregulated pro-inflammatory cytokines; upregulated genes encoding occludin, MUC-2 and JAM; and restored the healthy architectures of colonic tissues. Taken together, these data suggest that QT-NPs could be a promising alternative to current IBD treatments.
... MTT and ELISA results showed that both miquelianin and quercitrin contributed at least partially to TARC inhibition and HA production without cytotoxic effects on HaCaT cells. Although several reports have demonstrated the anti-inflammatory effect of miquelianin (Derlindati et al., 2012;Guo et al., 2013;Xu et al., 2021) and quercitrin (Camuesco et al., 2004;Comalada et al., 2005;Tang et al., 2019), to the best of our knowledge, this study is the first to demonstrate the role of miquelianin and quercitrin in anti-inflammatory and skin-moisturizing The putative identification of five major phytochemicals in FPE is listed in the lower table. FPE (10 mg/mL) was introduced into the UPLC-MS system, and separation and detection conditions are described in Supplementary Table S3. ...
Ethnopharmacological relevance
The meadowsweet family (genus Filipendula) includes about 30 species, which have been traditionally used in folk medicine to treat various inflammatory diseases. Particularily, F. palmata (Pall.) Maxim. (Siberian meadowsweet) were traditionally and widely used as an ethnic herb in the Oroqen application.
Aim of the study
Limited studies have been documented on most species, except for two main species, F. ulmaria (L.) Maxim. and F. vulgaris Moench. Thus, this study aimed to investigate the anti-inflammatory and skin-moisturizing effects of 70% ethanolic extract (FPE) of F. palmata on human epidermal keratinocytes.
Materials and methods
HaCaT keratinocytes were treated with FPE under different conditions. Quantitative real time-PCR, enzyme-linked immunosorbent assay, western blotting methods were used to evaluate the effect and molecular mechanism of the cells treated with FPE. The bioactive compounds in FPE, which are responsible for biological activities, was explored using mass spectrometric analysis.
Results
FPE did not show a cytotoxic effect on the cells at concentrations below 200 μg/mL. FPE significantly suppressed the intracellular reactive oxygen species and mitochondrial superoxide of inflamed HaCaT cells induced by tumor necrosis factor-α and interferon-γ (T + I) and inflammatory chemokine genes and proteins, such as CC chemokine ligands (CCL5, CCL17, and CCL27) and CXC chemokine ligand (CXCL8). These anti-inflammatory activities of FPE were mediated by the downregulation of mitogen-activated protein kinase (MAPK) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathways. In normal HaCaT cells, FPE significantly promoted the production of hyaluronic acid (HA) via the downregulation of hyaluronidase (HYAL1 and HYAL2) and upregulation of hyaluronic acid synthase (HAS1, HAS2, and HAS3) genes, and these effects seemed to be associated with the PI3K/Akt/NF-κB signaling. Ultraperformance liquid chromatography-tandem mass spectrometry indicated that FPE contains four flavonoids, including (+)-catechin, miquelianin, scutellarin, and quercitrin, as its major phytochemicals. Finally, we demonstrated that miquelianin and quercitrin contribute partially to the anti-inflammatory and HA-producing activity of FPE without cytotoxic effects on HaCaT cells.
Conclusions
Our findings suggest that topical applications of FPE can be utilized as an alternative therapy for treating skin inflammation. Additionally, our findings serve as a reference in applying FPE as a functional ingredient to treat inflammatory skin diseases and promote skin health.
... A blind technician monitored daily the Disease Activity Index (DAI), which is based on the average of 3 parameters; weight loss, stool consistency and rectal bleeding. To assign DAI scores the proposed criteria by Camuesco et al. 9 , were followed (Supplementary table S1). Rectal bleeding was scored as visible blood in feces, from slightly bloody to highly bloody stools (Supplementary table S1). ...
Inflammatory bowel disease (IBD) is a complex, chronic, relapsing and heterogeneous disease induced by environmental, genomic, microbial and immunological factors. MCJ is a mitochondrial protein that regulates the metabolic status of macrophages and their response to translocated bacteria. Previously, an acute murine model of DSS-induced colitis showed increased disease severity due to MCJ deficiency. Unexpectedly, we now show that MCJ-deficient mice have augmented tumor necrosis factor α converting enzyme (TACE) activity in the context of chronic inflammation. This adaptative change likely affects the balance between soluble and transmembrane TNF and supports the association of the soluble form and a milder phenotype. Interestingly, the general shifts in microbial composition previously observed during acute inflammation were absent in the chronic model of inflammation in MCJ-deficient mice. However, the lack of the mitochondrial protein resulted in increased alpha diversity and the reduction in critical microbial members associated with inflammation, such as Ruminococcus gnavus, which could be associated with TACE activity. These results provide evidence of the dynamic metabolic adaptation of the colon tissue to chronic inflammatory changes mediated by the control of mitochondrial function.
... Body weight, presence of blood in feces, and stool consistency were assessed daily, and a score was assigned to each of these parameters according to previously proposed criteria (Table 1). These scores were used to calculate the average daily disease activity index (DAI) [14]. Mice were euthanized on day 11 for further experiments. ...
Ulcerative colitis (UC) is one of the major subtypes of inflammatory bowel disease with unknown etiology. Probiotics have recently been introduced as a treatment for UC. Tetragenococcus halophilus (T. halophilus) is a lactic acid-producing bacterium that survives in environments with high salt concentrations, though little is known about its immunomodulatory function as a probiotic. The purpose of this study is to determine whether T. halophilus exerts an anti-inflammatory effect on intestinal inflammation in mice. Colitis was induced in C57BL/6J mice by feeding 4% DSS in drinking water for 7 days. T. halophilus was orally administered with DSS. Anti-inflammatory functions were subsequently evaluated by flow cytometry, qRT-PCT, and ELISA. Gut microbial composition was analyzed by 16S rRNA metagenomic analysis. DSS-induced colitis mice treated with T. hal-ophilus showed less weight loss and significantly suppressed colonic shortening compared to DSS-induced colitis mice. T. halophilus significantly reduced the frequency of the dendritic cell activation molecule CD83 in peripheral blood leukocytes and intestinal epithelial lymphocytes. Frequencies of CD8+NK1.1+ cells decreased in mice with colitis after T. halophilus treatment and IL-1β levels were also reduced. Alteration of gut microbiota was observed in mice with colitis after administration of T. halophilus. These results suggest T. halophilus is effective in alleviating DSS-induced colitis in mice by altering immune regulation and gut microbiome compositions.
... QUE could provide effective control of the cellular inflammatory response by effectively inhibiting the mRNA expression levels of IL-6 and IL-8 while promoting the mRNA expression levels of IL-10. This is consistent with the findings that QUE has in vitro anti-inflammatory activity [23][24][25]. ...
Porcine circovirus type 2 (PCV2) is the main pathogen causing porcine circovirus-associated diseases (PCVD/PCVADs), and infection of the host induces immunosuppression. Since quercitrin (QUE) has anti-inflammatory and antiviral activity, it is worth exploiting in animal diseases. In this study, the interventional effects and the molecular mechanism of QUE on PCV2-induced oxidative stress and inflammatory responses in 3D4/2 cells and the modulation of histone acetylation modifications were investigated. The ROS production was measured by DCFH-DA fluorescent probes. HAT and HDAC enzyme activity were determined by ELISA. Histone acetylation, oxidative stress and inflammation-related gene expression levels were measured by q-PCR. Histone H3 and H4 (AcH3 and AcH4) acetylation, oxidative stress and inflammation-related protein expression levels were measured by Western blot. The results showed that QUE treatment at different concentrations on PCV2-infected 3D4/2 cells was able to attenuate the production of ROS. Moreover, QUE treatment could also intervene in oxidative stress and decrease the enzyme activity of HAT and the mRNA expression level of HAT1, while it increased the enzyme activity of HDAC and HDAC1 mRNA expression levels and downregulated histone H3 and H4 (AcH3 and AcH4) acetylation modification levels. In addition, QUE treatment even downregulated the mRNA expression levels of IL-6, IL-8, IκB, AKT and p38, but upregulated the mRNA expression levels of IL-10, SOD, GPx1, p65, Keap1, Nrf2, HO-1 and NQO1. As to protein expression, QUE treatment downregulated the levels of iNOS, p-p65 and IL-8 as well as the phosphorylation expression of IκB and p38, while it upregulated the levels of HO-1 and NQO1. It was shown that QUE at 25, 50 or 100 μmol/L regulated p38MAPK and PI3K/AKT signaling pathways by downregulating cellular histone acetylation modification levels while inhibiting the NF-κB inflammatory signaling pathway and activating the Nrf2/HO-1 antioxidant signaling pathway, thus regulating the production of inflammatory and antioxidant factors and exerting both anti-inflammatory and antioxidant effects.
... Beyond simply defining quercitrin as the anti-sickling chemical, we considered its mode of action. Quercitrin has been previously demonstrated to have a low toxicity profile on mouse macrophages (IC50 of approximately 0.1 mg/mL) [45] and to have potent antioxidant [46,47], antiapoptotic [48,49], anti-leishmanial [50], anti-diarrhoeal [51], antinociceptive [52], and anti-inflammatory activities [53]. ...
Alchornea cordifolia Müll. Arg. (commonly known as Christmas Bush) has been used traditionally in Africa to treat sickle cell anaemia (a recessive disease, arising from the S haemoglobin (Hb) allele), but the active compounds are yet to be identified. Herein, we describe the use of sequential fractionation coupled with in vitro anti-sickling assays to purify the active component. Sickling was induced in HbSS genotype blood samples using sodium metabisulphite (Na2S2O5) or through incubation in 100% N2. Methanol extracts of A. cordifolia leaves and its sub-fractions showed >70% suppression of HbSS erythrocyte sickling. The purified compound demonstrated a 87.2 ± 2.39% significant anti-sickling activity and 93.1 ± 2.69% erythrocyte sickling-inhibition at 0.4 mg/mL. Nuclear magnetic resonance (NMR) spectra and high-resolution mass spectroscopy identified it as quercitrin (quercetin 3-rhamnoside). Purified quercitrin also inhibited the polymerisation of isolated HbS and stabilized sickle erythrocytes membranes. Metabolomic comparisons of blood samples using flow-infusion electrospray-high resolution mass spectrometry indicated that quercitrin could convert HbSS erythrocyte metabolomes to be like HbAA. Sickling was associated with changes in antioxidants, anaerobic bioenergy, and arachidonic acid metabolism, all of which were reversed by quercitrin. The findings described could inform efforts directed to the development of an anti-sickling drug or quality control assessments of A. cordifolia preparations.
... Sections of 5 μm were obtained, deparaffinized, rehydrated, and submitted to staining in eosin-hematoxylin for morphological analysis. e histological damage was performed according to Utrilla et al. [20] and Camuesco et al. [21], considering epithelial loss, edema, cellular infiltration, goblet cells depletion, and the condition of the crypts. e mucin levels were quantified through histochemical analysis on the sections obtained as described above using the periodic acid Schiff's (PAS) technique, which stained glycoproteins like mucins in pink. ...
The hydroalcoholic extract of B. dracunculifolia (HEBD) and its major compound p-coumaric acid were evaluated against the severity of intestinal inflammation and behavioral changes like depressive and anxious behavior in colitis mice. Colitis was induced in Swiss mice by oral dextran sulfate sodium (DSS) administration for five days. The mice received vehicle (10 ml/kg), HEBD (3, 30, or 300 mg/kg), or p-coumaric acid (15 mg/kg) orally, once a day for twelve days. Behavioral tests were performed on the 11th and 12th days after the beginning of the treatments. Moreover, the colon, cortex, and hippocampus were collected to analyze oxidative and inflammatory parameters. The treatment with HEBD (300 mg/Kg), but not p-coumaric acid, showed decreased disease activity index (DAI) values compared to the vehicle group and partially preserved the villi architecture and mucin levels. Furthermore, the HEBD increased the antioxidant defenses in the colon and hippocampus and reduced the myeloperoxidase activity and IL-6 levels in the colon from colitis mice. Colitis mice treated with HEBD did not show depressive-like behavior in the tail suspension test. HEBD reduced colon inflammation, while it maintains antioxidant defenses and mucin levels in this tissue. It may reduce neuropsychiatric comorbidities associated with colitis through its antioxidant effects.
... Authors found that rats chronically treated with quercitrin, a flavonoid also identified in S8, had reduced levels of TNF-α and showed a protective effect in induced colitis (Dönder et al., 2018). In another in vivo colitis model, the authors found that quercetrin decreased the recruitment of macrophages and neutrophils as well as iNOS and NF-κB expression (Camuesco et al., 2004). Lastly, another study reported that quercetrin reduced the progression of colitis in rats by decreasing MPO (myeloperoxidase) and iNOS levels (Comalada et al., 2005). ...
We determined the phytochemical composition, anti-inflammatory mechanism of action, ROS/RNS scavenging capacity and systemic toxicity of a purified subfraction (S8) of Eugenia selloi. The composition of S8 was assessed by LC-ESI-QTOF-MS; the anti-inflammatory activity in RAW264.7 macrophages through NF-κB activation and biomarkers by multiplex in THP-1 cells; neutrophil migration, intravital microscopy and ICAM-1 expression in mice; NETs formation and CD11b expression; S8 scavenging capacity of ROS/RNS; toxicity in Galleria mellonella larvae model. Coumaric acid, quercetrin and vanillic acid were identified. S8 decreased NF-κB activation, IL-1β, IL-6, IL-10, MDC and MCP-1 levels, reduced neutrophil migration and ICAM-1 expression in mice; S8 did not interfere NET formation and CD11b expression, exhibited high antioxidant and showed negligible toxicity. E. selloi proved to be a promising, yet underexplored source of bioactive compounds, which can be useful employed in agribusiness and in the pharmaceutical and food industry to develop new products or human health supplies.
... In non-lesional skin biopsies of patients suffering from systemic lupus erythematosus, iNOS expression in endothelial cells and keratinocytes was demonstrated [34]. NO synthase inhibition is even hypothesized to be a treatment strategy in different diseases, including those involving autoimmune mechanisms in their pathogenesis [2,5,[35][36][37]. The production of NO is increased in various skin diseases (atopic dermatitis, contact dermatitis, psoriasis) [22]. ...
Airway inflammation is related to increased nitric oxide production. It can be assessed noninvasively with exhaled nitric oxide measurement. As airway inflammation was supposed to be present in chronic urticaria and angioedema patients we hypothesized increased exhaled nitric oxide in this group. Twenty-six symptomatic chronic urticaria patients with an acute episode of pharynx angioedema (17 women and 9 men, median age 35) were included in the study group. None of the patients reported a history of asthma, allergic rhinitis or cigarette smoking. The control group consisted of 29 non-smoking healthy subjects (19 women and 10 men, median age 22) without any history of atopy. Exhaled nitric oxide measurement was performed in all subjects. Exhaled nitric oxide levels in the angioedema group did not differ statistically significantly from those detected in healthy subjects (15.5 ppb and 17.0 ppb respectively). Our results indicate the lack of airway inflammation in chronic urticaria patients with pharynx angioedema.
... Also, the expression of LPS-induced iNOS expression was diminished by C. tricuspidata extract application as indicated on the Western blot gel. These data suggest the in vitro anti-inflammatory activity of C. tricuspidata extract, via regulating NO production and iNOS expression (Camuesco et al., 2004). The suppressive effect of C. tricuspidata extract on the allergic inflammation in 2,4dinitrochlorobenzene (DNCB)-induced mouse model was investigated, as depicted in Fig. 2. The repeated application of DNCB on the shaved dorsal skin of mice induced atopic dermatitis-like skin inflammation such as erythema, lichenification, scaliness, dryness, and thickening as shown in for dried extract volume. ...
Aim: This study aims at investigating the effect of ethanol extract of Cudrania tricuspidata twigs on in vitro and in vivo allergic inflammation. Methodology: The ethanol extract of twigs from Cudrania tricuspidata (CTE) was prepared. The effects of CTE on the lipopolysaccharide (LPS)-induced production of nitric oxide (NO) in Raw 264.7 cells were examined. 2,4-Dinitrochlorobenzene (DNCB)-induced allergic inflammation model of mouse was constructed for in vivo study. The anti-oxidative, anti-inflammatory and anti-allergic effects of CTE were examined through DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Results: The LPS-induced NO level was significantly reduced by Cudrania tricuspidata application in Raw 264.7 cells. LPS-induced inducible nitric oxide synthase (iNOS) expression was also reduced by CTE, showing CTE’s anti-inflammatory activity. Moreover, CTE reduced DNCB-induced IgE level in the mouse serum. The suppressive effect on the allergic inflammation stimulated by DNCB in the mouse model was investigated in terms of IL-4, IFN-γ, TNF-α level and PAR-2 expression. Interpretation: The ethanol extract of Cudrania tricuspidata twigs can be developed as a potent therapeutics for allergic inflammation.
... In the intervention period, the body weight and stool consistency of mice were observed on time. DAI was scored as earlier described (Table S1) [17,18]. After intervention, animals were humanely sacrificed by cervical dislocation, and the colons were removed. ...
A growing number of healthy dietary ingredients in fruits and vegetables have been shown to exhibit diverse biological activities. Phloretin, a dihydrochalcone flavonoid that is abundant in apples and pears, has anti-inflammatory effects on ulcerative colitis (UC) mice. The gut microbiota and metabolism are closely related to each other due to the existence of the food-gut axis in the human colon. To investigate the interplay of faecal metabolites and the microbiota in UC mice after phloretin treatment, phloretin (60 mg/kg) was administered by gavage to ameliorate dextran sulfate sodium (DSS)-induced UC in mice. Gut microbes and faecal metabolite profiles were detected by high-throughput sequencing and liquid chromatography mass spectrometry (LC-MS) analysis, respectively. The correlations between gut microbes and their metabolites were evaluated by Spearman correlation coefficients. The results indicated that phloretin reshaped the disturbed faecal metabolite profile in UC mice and improved the metabolic pathways by balancing the composition of faecal metabolites such as norepinephrine, mesalazine, tyrosine, 5-acetyl-2,4-dimethyloxazole, and 6-acetyl-2,3-dihydro-2-(hydroxymethyl)-4(1H)-pyridinone. Correlation analysis identified the relations between the gut microbes and their metabolites. Proteus was negatively related to many faecal metabolites, such as norepinephrine, L-tyrosine, laccarin, dopamine glucuronide, and 5-acetyl-2,4-dimethyloxazole. The abundance of unidentified Bacteriodales_S24-7_group was positively related to ecgonine, 15-KETE and 6-acetyl-2,3-dihydro-2-(hydroxymethyl)-4(1H)-pyridinone. The abundance of Christensenellaceae_R-7_group was negatively related to the levels of 15-KETE and netilmicin. Stenotrophomonas and 15-KETE were negatively related, while Intestinimonas and alanyl-serine were positively related. In conclusion, phloretin treatment had positive impacts on faecal metabolites in UC mice, and the changes in faecal metabolites were closely related to the gut microbiota.
... In acute inflammation, there is a rapid, early influx of neutrophils and ED1-positive macrophages that is associated with an increase in pro-Abbreviations: DNP, dinitrophenol; DMEM, Dulbecco's minimal essential medium; ENS, enteric nervous system; GDNF, glial cell line derived neurotrophic factor; HIF-1α, hypoxia-inducible factor 1α; IBD, inflammatory bowel disease; Nec-1, necrostatin-1; OMG, o-methyl glucose; RET, rearranged in transfection; RIP1K, receptor-interacting serine/threonine-protein kinase 1; SM/MP, smooth muscle/myenteric plexus; TNBS, trinitrobenzene sulphonic acid. inflammatory cytokines such as TNFa and IL-1b in the intestinal milieu (Camuesco et al., 2004). These infiltrating cells can be directly damaging via high levels of nitric oxide (NO) from inducible nitric oxide synthase (iNOS). ...
Intestinal inflammation challenges both function and structure of the enteric nervous system (ENS). In the animal model of TNBS-induced colitis, an influx of immune cells causes early neuron death in the neuromuscular layers, followed by axonal outgrowth from surviving neurons associated with upregulation of the neurotrophin GDNF (glial cell line-derived neurotrophic factor). Inflammation could involve ischemia and metabolic inhibition leading to neuronal damage, which might be countered by a protective action of GDNF. This was examined in a primary co-culture model of rat myenteric neurons and smooth muscle, where metabolic challenge was caused by dinitrophenol (DNP), O-methyl glucose (OMG) or hypoxia. These caused the specific loss of 50% of neurons by 24 h that was blocked by GDNF both in vitro and in whole mounts. Neuroprotection was lost with RET inhibition by vandetanib or GSK3179106, which also caused neuron loss in untreated controls. Thus, both basal and upregulated GDNF levels signal via RET for neuronal survival. This includes a key role for upregulation of HIF-1α, which was detected in neurons in colitis, since the inhibitor chetomin blocked rescue by GDNF or ischemic pre-conditioning in vitro. In DNP-treated co-cultures, neuron death was not inhibited by zVAD, necrosulfonamide or GSK872, and cleaved caspase-3 or − 8 were undetectable. However, combinations of inhibitors or the RIP1kinase inhibitor Nec-1 prevented neuronal death, evidence for RIPK1-dependent necroptosis. Therefore, inflammation challenges enteric neurons via ischemia, while GDNF is neuroprotective, activating RET and HIF-1α to limit programmed cell death. This may support novel strategies to address recurrent inflammation in IBD.
... Myricetin is a natural polyhydroxy flavonoid compound extracted from the bark, plant seeds and leaves of Myrica rubra (Jones et al., 2011;Imran et al., 2019a;Wang et al., 2019b). The pharmacological activities of these two flavonols, such as antitumor, anti-inflammation, antibiosis, and antioxidation, have been studied extensively (Camuesco et al., 2004). Park et al. reported that kaempferol supplementation in diet mitigated the DSS-induced colitis through a decrease in the biochemical and clinical inflammatory factors, such as IL-6, IL-1b, COX-2, TNF-a, and iNOS, and reduction in the MPO, PGE2, and NO levels in colonic mucosa (Semwal et al., 2016). ...
Inflammatory bowel disease (IBD) represents chronic recurrent intestinal inflammation resulting from various factors. Crohn’s disease (CD) and ulcerative colitis (UC) have been identified as the two major types of IBD. Currently, most of the drugs for IBD used commonly in the clinic have adverse reactions, and only a few drugs present long-lasting treatment effects. Moreover, issues of drug resistance and disease recurrence are frequent and difficult to resolve. Together, these issues cause difficulties in treating patients with IBD. Therefore, the development of novel therapeutic agents for the prevention and treatment of IBD is of significance. In this context, research on natural compounds exhibiting anti-inflammatory activity could be a novel approach to developing effective therapeutic strategies for IBD. Phytochemicals such as astragalus polysaccharide (APS), quercetin, limonin, ginsenoside Rd, luteolin, kaempferol, and icariin are reported to be effective in IBD treatment. In brief, natural compounds with anti-inflammatory activities are considered important candidate drugs for IBD treatment. The present review discusses the potential of certain natural compounds and their synthetic derivatives in the prevention and treatment of IBD.
... In this study, AA produced a signi cant increase in both mRNA and protein expression of iNOS that was greatly attenuated by UMB administration. Several experimental studies showed that iNOS expression level is increased in IBD [49,50]. Also, iNOS expression and NO production are elevated in IBD patients' colonic tissue [51]. ...
Ulcerative colitis (UC) is a common chronic, idiopathic inflammatory bowel disease associated with inflammatory perturbation and oxidative stress. Umbelliferone (UMB) is a potent anti-inflammatory and antioxidant coumarin derivative. Depending on the possible mechanisms, we aimed to explore and elucidate the therapeutic potential of UMB on UC-inflammatory response and oxidative injury-induced via intrarectal administration of acetic acid (AA). Rats were assigned into four groups: control group, UMB (30 mg/kg) treated group, colitis model group (2 ml of AA; 3% v/v), and colitis treated with UMB groups. Our results exhibited that UMB improved macroscopic and histological tissue injury caused by the AA. Mechanistically, UMB reduced the elevated TNF-α, IL-6, MPO and VCAM-1 via effective downregulation of TLR-4, NF-κB and iNOS signaling pathway, thereby mediated potent anti-inflammatory effects. Moreover, UMB administration resulted in effective up-regulation of both PPARγ and SIRT1 signaling pathways, thereby inhibited both oxidative injury and inflammatory response. Conclusively, UMB protected against AA-induced UC in rats through suppressing of the TLR4/NF-κB-p65/iNOS signaling pathway and promoting the PPARγ/SIRT1 signaling. Indeed, our data proved the effectiveness of UMB in UC and introduced it as a potential therapeutic beneficial applicant for clinical application.
... Flavonoids may inhibit pro-inflammatory cytokines production by blocking the binding of NF-κB to DNA, as well as inhibiting mitogen-activated protein kinase (MAPK) and STAT activation (Salaritabar et al. 2017). In fact, Camuesco et al. (2004) and Vezza et al. (2016) proposed that the anti-inflammatory effects of quercitrin might be related to a decrease in iNOS expression through downregulation of NF-κB in colonic tissue. In addition, the administration of quercetin remarkably decreased the levels of different cytokines in the inflamed colon induced by DSS (Miller, 1999;Westphal et al. 2012;Oz et al. 2013). ...
Background
Pistacia lentiscus L. (PL) is a flowering plant traditionally used in the treatment of gastrointestinal disorders. The extracts of this plant are endowed with strong pharmacological activities. The aim of our current study was to investigate the anti-inflammatory and potential therapeutic effects of PL leaves aqueous extract (PLAE) against Dextran Sulfate Sodium (DSS)-induced acute colitis.Materials and methodsThe therapeutic effect of PLAE was evaluated after orally administration of 3% DSS alone or concomitantly with PLAE (50, 100 or 200 mg/Kg). Mucosal lesions were assessed by macroscopic and histopathological examination. In this context, hemorrhage, diarrhea, weight loss, and disease activity index (DAI) were determined daily throughout the experiment. In the same way, hematoxylin–eosin and Alcian blue staining of colonic mucosal were used to evaluate, respectively, mucosal damages and mucus production. Furthermore, the levels of nitric oxide (NO), and pro-inflammatory cytokines [tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6)] were measured in plasma, as well as in colonic explants and peritoneal macrophages cultures supernatants.ResultsAdministration of DSS + PLAE indicated a significant reduction in clinical score of acute colitis DAI compared to DSS alone administration. Interestingly, histological analysis of the mucosa showed that DSS + PLAE-treated groups exhibited almost normal histology evidenced by an intact epithelium structure and less inflammatory cell infiltration in the mucosa. Alcian bleu staining revealed that DSS + PLAE-treated groups displayed almost normal mucus production. Importantly, a significant decrease in pro-inflammatory mediators (NO, IL-6 and TNF-α) levels in dose-dependent manner was reported in plasma, and culture supernatants of colonic explants and peritoneal macrophages from DSS + PLAE-treated mice compared to the DSS group.Conclusion
Our results showed that the systemic and local anti-inflammatory activities of aqueous leaves extract of PL improve the clinical signs of acute colitis. Our data suggest that PLAE has beneficial effects and could constitute a promising approach against acute ulcerative colitis by targeting the deregulated immune response.
... These results indicate that the active compound is quercetin, but that its glycoside quercitrin has to be orally administered for quercetin to be released in the colon via hydrolysis by the intestinal microbiota. This conclusion was supported by microbial fermentation experiments, showing that the intestinal microbiota are able to hydrolyze quercitrin to produce quercetin [41,42]. ...
A disturbed interaction between the gut microbiota and the mucosal immune system plays a pivotal role in the development of inflammatory bowel disease (IBD). Various compounds that are produced by the gut microbiota, from its metabolism of diverse dietary sources, have been found to possess anti-inflammatory and anti-oxidative properties in in vitro and in vivo models relevant to IBD. These gut microbiota-derived metabolites may have similar, or more potent gut homeostasis-promoting effects compared to the widely-studied short-chain fatty acids (SCFAs). Available data suggest that mainly members of the Firmicutes are responsible for producing metabolites with the aforementioned effects, a phylum that is generally underrepresented in the microbiota of IBD patients. Further efforts aiming at characterizing such metabolites and examining their properties may help to develop novel modulatory microbiome therapies to treat or prevent IBD.
... The flavonoid heteroside quercitrin (quercetin-3-O-ramnoside) (94) was isolated from S. rebaudiana as documented in the Stevia genus [1]. The biological activity of this compound has been extensively studied through the years, involving anti-inflammatory activity determined by Camuesco et al. [235], antiproliferative and proapoptotic effects by Cincin et al. [236], anti-Dengue virus 2 [237], osteoporosis attenuation [238], hair growth stimulation [239], improvement of hyperlipidemia and hepatic steatosis in ovariectomized mice [240], and inhibition of α-glicosidase [241]. Like other flavonoids discussed in this update, quercitrin was reviewed by Boniface and Ferreira et al. [176], showing antiprotozoal activity against P. falciparum (43.4% inhibition after 48 h), inhibitory effects on L. amazonensis arginase (IC50 = 10.0 μM), and activity against Dengue virus 2 (DENV-2 NS2B) (IC50 = 43.6 μM) and Dengue virus 3 (DENV-3 NS2B) (IC50 = 32.0 μM). ...
The Stevia genus (Asteraceae) comprises around 230 species, distributed from the southern United States to the South American Andean region. Stevia rebaudiana, a Paraguayan herb that produces an intensely sweet diterpene glycoside called stevioside, is the most relevant member of this genus. Apart from S. rebaudiana, many other species belonging to the Stevia genus are considered medicinal and have been popularly used to treat different ailments. The members from this genus produce sesquiterpene lactones, diterpenes, longipinanes, and flavonoids as the main types of phytochemicals. Many pharmacological activities have been described for Stevia extracts and isolated compounds, antioxidant, antiparasitic, antiviral, anti-inflammatory, and antiproliferative activities being the most frequently mentioned. This review aims to present an update of the Stevia genus covering ethnobotanical aspects and traditional uses, phytochemistry, and biological activities of the extracts and isolated compounds.
... Therefore, we have investigated the protective effect of Albiziae flos (dry inflorescence or the bud of Albizia julibrissin Durazz.), a traditional Chinese medicine rich in flavonoids, on APAPinduced acute liver injury and found that its active ingredient is quercitrin (Que). As a natural flavonoid with a wide range of pharmacological activities, quercitrin has been proven to have antioxidant, anti-inflammatory, antitumor, and antidepressant effects (Camuesco et al., 2004;Li et al., 2016;Xiong et al., 2020). Quercitrin is known to have protective effects on liver injury; however, its mechanism of action remains to be further elucidated (Raja et al., 2007;Truong et al., 2016). ...
The flavonoid quercitrin has a strong antioxidant property. It is also reported to have a protective effect on the liver. However, the mechanism by which it exerts a protective effect on the liver is not fully understood. The objective of this article is to confirm the protective effect of quercitrin extracted from Albiziae flos on acetaminophen (APAP)-induced liver injury and to explain its mechanism. In the in vivo study, quercitrin was administered orally to BALB/c mice at a dose of 50, 100, and 200 mg/kg for seven consecutive days. APAP (300 mg/kg) was injected intraperitoneally after a last dose of quercitrin was administered. Determination of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), reactive oxygen species (ROS), superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GSH-Px), catalase (CAT), and malondialdehyde (MDA) levels showed that quercitrin effectively attenuated APAP-induced acute liver injury in mice. Results of the in vitro study showed that quercitrin reduced the levels of ROS, protected mitochondria from damage, and restored the activity of mitochondrial complex I in APAP-treated L-02 cells. The addition of rotenone which is an inhibitor of complex I blocked the protective effect of quercitrin. The expression of mitochondrial complex I was also maintained by quercitrin. Our results suggest that quercitrin can maintain the level of mitochondrial complex I in injured cells and restore its activity, which reduces the production of ROS, protects the mitochondria from oxidative stress, and has a protective effect on the liver.
Euphorbia hirta and lactuca virosa are used to treat various ailment traditionally. This study aims at evaluating the antitussive, expectorant and analgesic effects of aqueous extracts of di-herbal formulation of Euphobia hirta and Lactuca virosa leaf. Citric acid induced, ammonia induced cough and phenol red dye secretion models were used. Hot plate and acetic acid induced writhing were used for analgesia. Combined 100mg/kg Euphorbia hirta and 50mg/kg lactuca virosa, 100mg/kg Euphorbia hirta and 100mg/kg lactuca virosa, 100mg/kg lactuca virosa only and 25 mg/kg of codeine phosphate reduces the number of cough bouts in the citric acid induced cough (P<0.05) compared to control. Combined 50mg/kg Euphorbia hirta and 100mg/kg lactuca virosa,100mg/kg Euphorbia hirta, 100mg/kg lactuca virosa and codeine phosphate reduces the number of cough bouts in the ammonia induced cough (P<0.001; P<0.0001) compared to the control. Combined 50mg/kg Euphorbia hirta and 100mg/kg lactuca virosa, 100mg/kg Euphorbia hirta and 50mg/kg lactuca virosa, 100mg/kg Euphorbia hirta and 100mg/kg lactuca virosa and 15mg/kg of Bromo-hexane increases the secretion of dye (P<0.0001; p<0.05) compared to control in phenol red dye secretion in mice. 100mg/kg Euphorbia hirta and 50mg/kg lactuca virosa,100mg/kg of Euphorbia hirta and 100mg/kg lactuca virosa and 3mg/kg Pentazocin increases the latency of pain threshold of mice (P<0.05). All the doses of the extract including 3mg/kg pentazocin increases the latency to pain threshold in the mice (P<0.001) after 2 hours. All the doses of the extract including aspirin reduces number of writhing (P<0.01). Euphorbia hirta and lactuca virosa has antitussive, expectorant and analgesic properties.
Ethnopharmacological relevance
Cochlospermum regium is well-known as “Algodãozinho do cerrado” in folk Brazilian medicine, and is used to fight infections, inflammation and skin disorders.
Aim of the study: To identify the phytochemical constituents and the effects of the ethanolic extract of C. regium leaves (EECR) on inflammation and pain, and the effects of C. regium gel (GEECR) on wound healing.
Materials and methods
Animals were treated with EECR (30–300 mg/kg) or GEECR (1.25 and 2.5%) and studies were conducted using carrageenan-induced pleurisy and paw edema tests, formalin-induced pain model, and excision wound model.
Results
In total, 25 compounds, including quercitrin, methyl gallate, and 1,2,3,4,6-pentagalloylhexose, with highest detectability were identified. The treatments reduced leukocyte migration, nitric oxide production, protein extravasation, edema, mechanical hyperalgesia, pain in both phases (neurogenic and inflammatory), cold hypersensitivity, and improved wound closure and tissue regeneration.
Conclusions
The present findings established the anti-inflammatory, anti-nociceptive, and wound healing potential of the leaves of C. regium, confirming the potential therapeutic effect of this plant.
Emerging evidence suggests that ferroptosis is involved in the pathogenesis of ulcerative colitis (UC). However, the key regulator of this process remains uncertain. In this study, we aimed to explore the roles of solute carrier (SLC) family 6 member 14 (SLC6A14) in regulating ferroptosis in UC. The expression of SLC6A14 was significantly increased and positively associated with that of prostaglandin-endoperoxide synthase 2 (PTGS2) in tissue samples from patients with UC. Moreover, a series of in vitro and in vivo experiments showed that SLC6A14 knockdown markedly suppressed ferroptosis. RNA sequencing revealed that SLC6A14 inhibited the expression of P21 (RAC1)-activated kinase 6 (PAK6) and that PAK6 knockdown abolished the effects of SLC6A14 on RAS-selective lethal 3 (RSL3)-induced ferroptosis in Caco-2 cells. Furthermore, chromatin immunoprecipitation (ChIP) and Western blot analysis demonstrated that SLC6A14 negatively regulated PAK6 expression in a CCAAT enhancer binding protein beta (C/EBPβ)-dependent manner. Collectively, these findings indicate that SLC6A14 facilitates ferroptosis in UC by promoting C/EBPβ expression and binding activity to inhibit PAK6 expression, suggesting that targeting SLC6A14-C/EBPβ-PAK6 axis-mediated ferroptosis may be a promising therapeutic alternative for UC.
Ulcerative colitis (UC) is challenging to treat and severely impacts patients and families. A previous study reported immunomodulatory and reduction of pro-inflammatory properties for the Lactiplantibacillus plantarum L15. This study aimed to analyze the preventive properties and mechanistic actions in an in vivo colitis model. The histopathological alteration, inflammation cytokines, and intestinal barrier function were analyzed. Subsequently, the cecal gut microbiota contents and products from different groups were detected. Finally, gene expressions related to the NF-κB signaling process were evaluated. L. plantarum L15 significantly decreased disease activity index (DAI), myeloperoxidase activity (MPO), pro-inflammatory cytokine (TNF-α, IL-1β, and IL-6) level, and increased weight change, colon length, and production of inflammation-suppressing cytokines. Furthermore, this strain supplementation substantially increased ZO-1, Occludin, and Claudin-1, and MUC2 mRNA expression levels with a corresponding decrease in serum lipopolysaccharide and D-lactic acid contents. In addition, L. plantarum L15 improved gut microbiota composition and increased short-chain fatty acid (SCFAs) in the colon content, which significantly reduced the transfer of NF-κB p65 to the nucleus. Our findings provide a theoretical basis for L. plantarum L15 as a preventive candidate for UC.
Abdominal pain is a common feature in IBD patients, and greatly compromises their quality of life. Therefore, the identification of new therapeutic tools to reduce visceral pain is one of the main goals for IBD therapy. Minocycline, a broad-spectrum tetracycline antibiotic, has gained attention in the scientific community because of its immunomodulatory and anti-inflammatory properties. The aim of this study was to evaluate the potential of this antibiotic as a therapy for the management of visceral pain in dextran sodium sulfate (DSS)-induced colitis in mice. Preemptive treatment with minocycline markedly reduced histological features of intestinal inflammation and the expression of inflammatory markers (Tlr4, Tnfα, Il1ß, Ptgs2, Inos, Cxcl2 and Icam1), and attenuated the decrease of markers of epithelial integrity (Tjp1, Ocln, Muc2 and Muc3). In fact, minocycline restored normal epithelial permeability in colitic mice. Treatment with the antibiotic also reversed the changes in the gut microbiota profile induced by colitis. All these ameliorative effects of minocycline on both inflammation and dysbiosis correlated with a decrease in ongoing pain and referred hyperalgesia, and with the improvement of physical activity induced by the antibiotic in colitic mice. Minocycline might constitute a new therapeutic approach for the treatment of IBD-induced pain.
Perspective: This study found that the intestinal anti-inflammatory effects of minocycline ameliorate DSS-associated pain in mice. Therefore, minocycline might constitute a novel therapeutic strategy for the treatment of IBD-induced pain.
Background:
Obesity is associated with an increased risk of developing Crohn's disease (CD), higher disease activity, and comparatively worse clinical outcomes.
Aim:
To investigate the role of mesenteric adipose tissue-derived exosomes in the pathogenesis of CD aggravation in obese individuals.
Methods:
First, we induced colitis in mice initiated on high-fat and normal diets and compared the severity of colitis. We then extracted and identified exosomes from mesenteric adipose tissue and determined the levels of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in mesenteric adipose tissue-derived exosomes and the colon. Next, we demonstrated an interaction between MALAT1 and the miR-15a-5p/activating transcription factor 6 (ATF6) axis. Finally, we explored the effects of mesenteric adipose tissue-derived exosomes extracted from mice fed a high-fat or normal diet on the severity of 2,4,6-trinitrobe-nzenesulfonic acid (TNBS)-induced colitis and ATF6-related endoplasmic reticulum stress pathways.
Results:
High-fat diet was found to aggravate TNBS-induced colitis in mice. The expression of MALAT1 in mesenteric adipose tissue-derived exosomes of high-fat diet-fed mice increased. The increased expression of MALAT1 in colon tissue exacerbated TNBS-induced colitis and activated the ATF6 endoplasmic reticulum stress pathway. This effect was partially reversed by the reduced expression of MALAT1 and overexpression of miR-15a-5p.
Conclusion:
Mesenteric adipose tissue-derived exosome-encapsulated long noncoding RNAs MALAT1 targets the colon and aggravates TNBS-induced colitis in obese mice, which may potentially act on the miR-15a-5p/ATF6 axis and activate endoplasmic reticulum stress.
Emerging evidence suggests that ferroptosis is involved in the pathogenesis of ulcerative colitis (UC). However, the key regulator of this process remains uncertain. In this study, we aimed to explore the roles of solute carrier (SLC) family 6 member 14 (SLC6A14) in regulating ferroptosis in UC. The expression of SLC6A14 was significantly increased and positively associated with that of prostaglandin-endoperoxide synthase 2 (PTGS2) in tissue samples from patients with UC. Moreover, a series of in vitro and in vivo experiments showed that SLC6A14 knockdown markedly suppressed ferroptosis. RNA sequencing revealed that SLC6A14 inhibited the expression of P21 (RAC1) activated kinase 6 (PAK6) and that PAK6 knockdown abolished the effects of SLC6A14 on RAS-selective lethal 3 (RSL3) -induced ferroptosis in Caco-2 cells. Furthermore, chromatin immunoprecipitation (ChIP) and Western blot analysis demonstrated that SLC6A14 negatively regulated PAK6 expression in a CCAAT enhancer binding protein beta (C/EBPβ)-dependent manner. Collectively, these findings indicate that SLC6A14 facilitates ferroptosis in UC by promoting C/EBPβ expression and binding activity to inhibit PAK6 expression, suggesting that targeting SLC6A14-C/EBPβ-PAK6 axis-mediated ferroptosis may be a promising therapeutic alternative for UC.
Quercitrin is a naturally available type of flavonoid that commonly functions as the dietary ingredient and supplement. So far, a wide spectrum of bioactivities of quercitrin have been revealed, including antioxidative stress, antiinflammation, anti‐microorganisms, immunomodulation, analgesia, wound healing, and vasodilation. Based on these various pharmacological activities, increasing studies have focused on the potency of quercitrin in diverse diseases in recent years, such as bone metabolic diseases, gastrointestinal diseases, cardiovascular and cerebrovascular diseases, and others. In this paper, by collecting and summarizing publications from the recent years, the natural sources, pharmacological activities and roles in various diseases, pharmacokinetics, structure–activity relationship, as well as the toxicity of quercitrin were systematically reviewed. In addition, the underlying molecular mechanisms of quercitrin in treating related diseases, the dose‐effect relationships, and the novel preparations were discussed on the purpose of broadening the application prospect of quercitrin as functional food and providing reference for its clinical application. Notably, clinical studies of quercitrin are insufficient at present, further high‐quality studies are needed to firmly establish the clinical efficacy of quercitrin.
Ulcerative colitis (UC) is a relapsing and remitting inflammatory bowel disease (IBD), but current conventional drugs lack efficacy. Astragalus polysaccharide (APS) is an active ingredient of Astragalus membranaceus and has been shown to ameliorate experimental colitis. In the present study, we aimed to investigate how APS affects the ferroptosis of intestinal epithelial cells in dextran sulfate sodium (DSS)-induced experimental colitis in mice. Our data showed that APS administration attenuated total weight loss, colon length shortening, disease activity index (DAI) scores, histological damage, and the expression of inflammatory cytokines in the colon of DSS-challenged mice. Moreover, we observed that treatment with APS obviously inhibited ferroptosis in both DSS-challenged mice and RSL3-stimulated Caco-2 cells, as indicated by the decrease in the expression of ferroptosis-associated genes (PTGS2, FTH, and FTL) and the levels of surrogate ferroptosis markers (MDA, GSH, and iron load). Mechanistically, the inhibitory effects of APS on ferroptosis in DSS-challenged mice and RSL3-stimulated Caco-2 cells were associated with the NRF2/HO-1 pathway. Collectively, our findings identify a new role of APS in preventing ferroptosis in a murine model of experimental colitis and human Caco-2 cells via inhibiting NRF2/HO-1 pathway.
Inflammatory bowel disease (IBD) is characterized by sustained inflammatory processes in the gastrointestinal tract. One of the most threatening risks for IBD patients is the development of colorectal cancer, resulting from the chronic inflammatory state. Current IBD treatment presents limitations in safety and efficacy. As such, it is of paramount importance to find novel therapeutic strategies. The antioxidant and anti-inflammatory properties of flavonoids are widely recognized. Flavonoids currently found in our daily diet are likely to yield biological actions at the gastrointestinal level, suggesting a potential protective effect in IBD. However, the number of studies concerning the effects of flavonoids on intestinal inflammation is limited. This chapter intends to summarize the known effects of flavonoids in the different phases of IBD inflammatory pathways, covering all the concerning available in vivo studies.
The interaction between lipase and quercetin 3-rhamnoside was studied by fluorescence spectroscopy, enzyme kinetics, and molecular dynamics simulation. The results showed that quercetin 3-rhamnoside had a strong quenching effect on the intrinsic fluorescence of lipase. The binding constant decreased with increasing temperature, and the number of binding sites approached 1. Thermodynamic parameters indicated that hydrogen bonding and van der Waals forces are the dominant forces when the interaction occurs. Circular dichroism spectroscopy and infrared spectroscopy proved that the ligand perturbed the structure of lipase. Enzyme kinetics results showed that quercetin 3-rhamnoside inhibited lipase, and the inhibitory effect was dose-dependent. Molecular dynamics simulation further explained the interaction mechanism and inhibitory effect. This study confirmed the inhibitory effect of quercetin 3-rhamnoside on lipase explained their binding mechanism, which will contribute to guiding the development of fat-reducing functional foods.
The promoter of the murine gene encoding inducible nitric oxide synthase (iNOS) contains an NF-kappa B site beginning 55 base pairs upstream of the TATA box, designated NF-kappa Bd. Reporter constructs containing truncated promoter regions, when transfected into macrophages, revealed that NF-kappa Bd is necessary to confer inducibility by bacterial lipopolysaccharide (LPS). Oligonucleotide probes containing NF-kappa Bd plus the downstream 9 or 47 base pairs bound proteins that rapidly appeared in the nuclei of LPS-treated macrophages. The nuclear proteins bound to both probes in an NF-kappa Bd-dependent manner, but binding was resistant to cycloheximide only for the shorter probe. The proteins binding both probes reacted with antibodies against p50 and c-rel but not RelB; those binding the shorter probe also reacted with anti-RelA (p65). Pyrrolidine dithiocarbamate, which acts as a specific inhibitor of NF-kappa B, blocked both the activation of the NF-kappa Bd-binding proteins and the production of NO in LPS-treated macrophages. Thus, activation of NF-kappa Bd/Rel is critical in the induction of iNOS by LPS. However, additional, newly synthesized proteins contribute to the NF-kappa Bd-dependent transcription factor complex on the iNOS promoter in LPS treated mouse macrophages.
Transgenic Arabidopsis thaliana and Sorghum sp. plants that overproduce citrate have been generated. These plants have been biochemically and genetically analyzed and used to study the role of organic acids in the iron nutrition of plants. Preliminary results reflect a possible participation of citrate in the acquisition and internal iron movilization in both species.
Transcription factors of the nuclear factor kappaB (NF-kappaB) family play an important role in the regulation of genes involved in inflammation. In inflammatory bowel diseases, proinflammatory cytokines known to be regulated by NF-kappaB are involved. The aim of this study was to investigate the role of NF-kappaB activation during mucosal inflammation in situ.
A monoclonal antibody, alpha-p65mAb, was applied for immunofluorescence and immunohistochemical analysis that recognizes activated NF-kappaB. Electrophoretic mobility shift assay was used to directly demonstrate the presence of active DNA-binding NF-kappaB.
Using the alpha-p65mAb antibody, activated NF-kappaB could be found in biopsy specimens from inflamed mucosa but was almost absent in uninflamed mucosa. The number of cells showing NF-kappaB activation correlated with the degree of mucosal inflammation but was not significantly different between inflamed mucosa from patients with Crohn's disease, ulcerative colitis, and nonspecific colitis or diverticulitis. NF-kappaB activation was localized in macrophages and in epithelial cells as identified by double-labeling techniques. Electrophoretic mobility shift assay with isolated lamina propria mononuclear cells and epithelial cells confirmed these results.
This study shows for the first time the activation of NF-kappaB during human mucosal inflammation in situ. In addition to macrophages, epithelial cells contained activated NF-kappaB, indicating an involvement in the inflammatory process.
The promoter of the murine gene encoding inducible nitric oxide synthase (iNOS) contains an NF-kappa B site beginning 55 base pairs upstream of the TATA box, designated NF-kappa Bd. Reporter constructs containing truncated promoter regions, when transfected into macrophages, revealed that NF-kappa Bd is necessary to confer inducibility by bacterial lipopolysaccharide (LPS). Oligonucleotide probes containing NF-kappa Bd plus the downstream 9 or 47 base pairs bound proteins that rapidly appeared in the nuclei of LPS-treated macrophages. The nuclear proteins bound to both probes in an NF-kappa Bd-dependent manner, but binding was resistant to cycloheximide only for the shorter probe. The proteins binding both probes reacted with antibodies against p50 and c-rel but not RelB; those binding the shorter probe also reacted with anti-RelA (p65). Pyrrolidine dithiocarbamate, which acts as a specific inhibitor of NF-kappa B, blocked both the activation of the NF-kappa Bd-binding proteins and the production of NO in LPS-treated macrophages. Thus, activation of NF-kappa B/Rel is critical in the induction of iNOS by LPS. However, additional, newly synthesized proteins contribute to the NF-kappa Bd-dependent transcription factor complex on the iNOS promoter in LPS-treated mouse macrophages.
Evidence of in vivo oxidant-induced injury in inflammatory bowel disease (IBD) is largely indirect. Colon epithelial crypt cells (CEC) from paired specimens of histologically normal and inflamed bowel from IBD patients with active disease were examined for altered protein thiol redox status as an indicator of oxidative damage. When CEC preparations from 22 IBD patients were labeled with the reduced-thiol-specific probe [14C]-iodoacetamide (IAM), there was decreased labeling of a number of proteins indicating oxidation of thiol groups in CEC from inflamed mucosa compared to paired normal mucosa, especially the loss of thiol labeling of a 37-kD protein which was almost completely lost. The loss of reduced protein thiol status for the 37-kD band was paralleled by loss of epithelial cell glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) enzyme activity, an enzyme known to contain an essential reduced cysteine (Cys149) at the active site. The identity of the 37-kD protein as GADPH monomer was confirmed by NH2-terminal amino acid sequence analysis. To examine whether this type of in vivo injury could be attributed to biologically relevant oxidants produced by inflammatory cells, CEC prepared from normal mucosa were exposed to H2O2, OCl-, nitric oxide (NO), and a model chloramine molecule chloramine T (ChT) in vitro. Dose-dependent loss of IAM labeling and GAPDH enzyme activity was observed. The efficacy (IC50) against IAM labeling was OCl- > ChT > H2O2 > NO (52 +/- 3, 250 +/- 17, 420 +/- 12, 779 +/- 120 microM oxidant) and OCl- > ChT > NO > H2O2 (89 +/- 17, 256 +/- 11, 407 +/- 105, 457 +/- 75 microM oxidant), respectively, for GAPDH enzyme activity. This study provides direct evidence of in vivo oxidant injury in CEC from inflamed mucosa of IBD patients. Oxidation and inhibition of essential protein function by inflammatory cells is a potential mechanism of tissue injury that may contribute to the pathogenesis of the disease and supports the exploration of compounds with antioxidant activity as new therapies for IBD.
Cyclooxygenase type 1 is constitutively expressed and accounts for synthesis of prostaglandins in the normal gastrointestinal tract. Cyclooxygenase-2 is expressed at sites of inflammation. Selective inhibitors of cyclooxygenase-2 have been suggested to spare gastrointestinal prostaglandin synthesis, and therefore lack the ulcerogenic effects associated with standard nonsteroidal antiinflammatory drugs. However, the effects of cyclooxygenase-2 inhibitors on inflamed gastrointestinal mucosa have not been examined. We examined cyclooxygenase-2 mRNA and protein expression before and after induction of colitis in the rat, the contribution of cyclooxygenase-2 to colonic prostaglandin synthesis during colitis and the effects of selective inhibitors of cyclooxygenase-2 on colonic injury in this model. Cyclooxygenase-2 mRNA expression increased three to sixfold during the period 24 h to 1 wk after induction of colitis, with marked increases in cyclooxygenase-2 protein expression in the lamina propria and muscularis of the colon during colitis. Cyclooxygenase-1 expression (mRNA and protein) was not affected by the induction of colitis. The prostaglandins produced during colitis were largely derived from cyclooxygenase-2. Treatment with selective cyclooxygenase-2 inhibitors resulted in exacerbation of colitis, with perforation occurring when the compounds were administered for a week. These studies demonstrate that suppression of cyclooxygenase-2 can result in exacerbation of inflammation-associated colonic injury.
It is postulated that an enhanced production of nitric oxide by inflamed intestine plays a role in the pathophysiology of active inflammatory bowel disease. In this study, systemic NOx concentrations and colonic nitric oxide synthase activity were determined in patients with ulcerative colitis or Crohn's disease. The relationship between these two parameters and disease activity, as well as differences in nitric oxide synthase activity between ulcerative colitis and Crohn's disease, were areas of specific focus. Patients with active ulcerative colitis and Crohn's disease had significantly elevated plasma NOx concentrations; a positive correlation was found between NOx values and inducible nitric oxide synthase activities in the active mucosa of these patients. In active ulcerative colitis, levels of inducible nitric oxide synthase were significantly elevated in both normal and inflamed mucosa, although inducible nitric oxide synthase activity was higher in the latter. These colonic inducible nitric oxide synthase activities correlated well with the results of endoscopic and histologic grading of inflammation. There was no increase in constitutive nitric oxide synthase activity in patients with active ulcerative colitis. However, constitutive nitric oxide synthase activity was significantly increased in the inflamed mucosa in patients with Crohn's disease. In Crohn's disease, elevated inducible nitric oxide synthase activity was found in both normal and inflamed mucosa, with no significant difference between the tissues. Such differences in nitric oxide production in the colonic mucosa possibly reflect the significant differences in the pathophysiology and characteristic clinical features between ulcerative colitis and Crohn's disease.
During a period of 6 month the risk of significant injuries on indoor climbing walls was survived. A total of 25,163 visitors were registrated at the 10 walls. Overall only 4 significant injuries were found, the injury-risk per visit was 0.016%.
Aim of this study was to assess the structural, ultrastructural, immunohistochemical, and clinical aspects in Sprague-Dawley rats with dextrane sulfate sodium (DSS)-induced colitis. Colitis was induced in Sprague-Dawley rats by seven days of DSS oral administration followed by seven days of tap water only (for one, two and three cycles). Controls were fed with water only. Segments of proximal, mid-, and distal colon of each animal were adequately prepared for light and scanning electron microscope observations. The severity of the lesions was scored histologically. For immunohistochemical study, a cocktail of S-100, NSE, and antineurofilament antibodies was used. Symptoms such as weight, feces consistency, diarrhea, hematochezia were recorded daily. From a clinical point of view symptoms appeared significantly later after the first cycle than after the second and third cycles and lasted significantly longer in the second and third cycles. Treated rats showed a slower weight gain rate by 20% compared to controls, and the whole colon length appeared to be significantly shorter after colitis induction compared to controls. Structural observations by light microscopy showed prominent involvement of the distal colon. Immunohistochemical study of both submucosal and myoenteric nerve plexuses was similar to controls. Scanning electron microscope observations of the colonic mucosal surface in colitis rats showed a complete subversion of its architecture, characterized by dilatations of gland crypt openings, dropout of goblet cells, and inhomogeneous distribution or lack of microvilli. These were most evident after the third cycle. In conclusion, experimental DSS colitis in SD rats appeared to be highly reproducible and shared most features with human UC, not only from a structural and clinical but also from an ultrastructural point of view.
Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.
Nitric oxide (NO) synthesis is up-regulated in inflammatory bowel disease. However, its role in the pathophysiology of this condition is controversial. The aims of this study were to assess whether nitric oxide administration ameliorates experimental colitis and to determine the possible mechanisms underlying its effects on intestinal inflammation. For this purpose, the NO donor diethylamine NONOate (DETA/NO; 0.01, 0.1, 1, 5, or 10 mg/kg/day), or the DETA moiety, was administered daily to mice with dextran sulfate sodium-induced colitis. Daily body weight and colonic pathologic alterations at Day 10 were determined. Leukocyte endothelial cell interactions in colonic venules were assessed with intravital microscopy, and expression of endothelial cell adhesion molecules was determined using radiolabeled antibodies. IL-12 and IFN-gamma production were measured in intestinal tissue. Colitis induced a significant loss of body weight, reduction of colon length, and increase in colon weight and myeloperoxidase activity. Administration of 1 mg/kg/day DETA/NO significantly attenuated these pathologic changes. The marked increase in leukocyte rolling and adhesion in colonic venules of colitic mice were significantly reduced by administration of 1 mg/kg/day DETA/NO. Development of colitis was associated with a marked increase in endothelial expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and P-selectin. Supplementation with NO significantly attenuated the up-regulation of endothelial intercellular adhesion molecule-1 and P-selectin, but not vascular cell adhesion molecule-1, in colonic tissue. NO abrogated the increase in IL-12 and IFN-gamma mRNA expression in the colon of colitic mice. The DETA moiety alone did not have any effect on any of the parameters studied. In conclusion, exogenous NO supplementation significantly ameliorates dextran sulfate sodium-induced colitis. This effect is related to a reduction in leukocyte recruitment and proinflammatory cytokine production.
Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.
Previous studies have revealed the beneficial effects exerted by dietary fiber in human inflammatory bowel disease, which were associated with an increased production of SCFA in distal colon. The aim of the present study was to elucidate the probable mechanisms involved in the beneficial effects of a fiber-supplemented diet (5% Plantago ovata seeds) in the trinitrobenzenesulfonic acid (TNBS) model of rat colitis, with special attention to its effects on the production of some of the mediators involved in the inflammatory response, such as tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO). Rats were fed the fiber-supplemented diet for 2 wk before TNBS colitis induction and thereafter until colonic evaluation 1 wk later. The results obtained showed that dietary fiber supplementation facilitated recovery from intestinal insult as evidenced both histologically, by a preservation of intestinal cytoarchitecture, and biochemically, by a significant reduction in colonic myeloperoxidase activity and by restoration of colonic glutathione levels. This intestinal anti-inflammatory effect was associated with lower TNFa levels and lower NO synthase activity in the inflamed colon, showing significant differences when compared with nontreated colitic rats. Moreover, the intestinal contents from fiber-treated colitic rats showed a significantly higher production of SCFA, mainly butyrate and propionate. We conclude that the increased production of these SCFA may contribute to recovery of damaged colonic mucosa because they constitute substrates for the colonocyte and, additionally, that they can inhibit the production of proinflammatory mediators, such as TNFalpha and NO.
The inflammatory bowel diseases (IBD; Crohn’s disease, ulcerative colitis) are a collection of chronic idiopathic inflammatory disorders of the intestine and/or colon. Although the pathophysiology of IBD is not known with certainty, a growing body of experimental and clinical data suggests that chronic gut inflammation may result from a dysregulated immune response to normal bacterial antigens. This uncontrolled immune system activation results in the sustained overproduction of reactive metabolites of oxygen and nitrogen. It is thought that some of the intestinal and/or colonic injury and dysfunction observed in IBD is due to elaboration of these reactive species. This review summarizes the current state-of-knowledge of the role of reactive oxygen species and nitric oxide in the pathophysiology of IBD.
Chronic intestinal inflammation induced by 2,4,6,-trinitrobenzene sulfonic acid (TNBS) is characterized by a transmural granulomatous colitis that mimics some characteristics of human Crohn's disease. Here, we show that the transcription factor NF-kappa B p65 was strongly activated in TNBS-induced colitis and in colitis of interleukin-10-deficient mice. Local administration of p65 antisense phosphorothioate oligonucleotides abrogated clinical and histological signs of colitis and was more effective in treating TNBS-induced colitis than single or daily administration of glucocorticoids. The data provide direct evidence for the central importance of p65 in chronic intestinal inflammation and suggest a potential therapeutic utility of p65 antisense oligonucleotides as a novel molecular approach for the treatment of patients with Crohn's disease.
Nuclear factor (NF)κB is a transcription factor that controls the transcription of a variety of cellular genes regulating the inflammatory response.
Many proinflammatory cytokines are transcriptionally regulated by NF-κB, and their increased expression has been implicated in the pathogenesis of inflammatory bowel disease (IBD). Even though
it seemed clear that the increase in proinflammatory cytokine production in IBD is crucial for the initiation and perpetuation
of chronic intestinal inflammation, the elements governing this dysregulation of enhanced cytokine production remained unclear.
This review discusses a series of recent studies that demonstrate the activation of NF-κB in the inflamed mucosa, and that shed new light on the central pathogenic role of NF-κB in chronic intestinal inflammation. In addition to describing the activation of NF-κB, excitement has been generated by reports that define the molecular targets of anti-inflammatory agents, and that demonstrate
the effective blockade of NF-κB in intestinal inflammation. These new insights into the activation and inhibition of NF-κB have opened new and promising avenues for a more specific treatment of chronic intestinal inflammation.
We examined the clinical and histopathological features of the dextran sulfate sodium (DSS) induced acute and chronic colitis in rats as a model for studying basic biology of the inflamed colonic mucosa. Acute colitis was induced in male Wistar rats by 4 days (AI) or 7 days (AII) of oral 5% (wt/vol) DSS (mol. wt. 54,000) in their drinking water. Chronic colitis was induced in 8 experimental groups: CI=7 days DSS followed by 10 days water (=one cycle); CII=two cycles; CIII to CVIII (three to eight cycles) received only 4 days 5% DSS followed by 10 days drinking water. The entire colons were examined histologically; dysplasia was graded as: indefinite/probably negative for dysplasia, indefinite/probably positive for dysplasia, low-grade dysplasia, or high-grade dysplasia. The earliest clinical findings in the acute colitis group over 4 days occurred on day 2 (hemoccult positive stools, loose stools or diarrhea and weight loss). The maximal disease activity was noted on day 7 accompanied by a 53% mortality rate. The histological inflammation scores were significantly higher on day 7 than on day 4. All rats had extensive ulcerations predominantly in the rectum and cecum. The number of rats having ulcerations was markedly lower in the chronic colitis groups. The majority (75%) of the crypt lesions suspicious for dysplasia were classified as mucosa indefinite/probably negative for dysplasia. We classified 18 crypt lesions as low-grade dysplasia and one lesion as high-grade dysplasia (after eight cycles). No invasive carcinoma was observed. Most low-grade dysplasias (83%) occurred after five cycles of DSS/water, located mostly in the rectum (44%) and colon transversum (33%). Our findings suggest that the DSS colitis model in rats may be an interesting model for studying the sequence chronic inflammation-dysplasia in human ulcerative colitis. Further long-term studies with the present DSS colitis model in rats might also prove it as a reliable model to study the sequence high-grade dysplasia and colitis associated-cancer.
1. Oral administration of quercitrin to rats for 3 days increases the mucosal glutathione contents in ileum and colon as well as inhibits non-enzymatic lipid peroxidation induced in membrane fractions from jejunal and colonic mucosa.2. After 7 days of treatment with quercitrin, rat intestinal oxidative status trends to normalize to control rats.
Flavonols are a group of naturally occurring compounds which are widely distributed in nature where they are found glycosylated primarily in vegetables and fruits. A number of studies have found both anti- and prooxidant effects for many of these compounds. The most widely studied because of their ubiquitous nature have been quercetin, a B-dihydroxylated and myricetin, a B-trihydroxylated flavonol. Some of their prooxidant properties have been attributed to the fact that they can undergo autooxidation when dissolved in aqueous buffer. Studying a number of factors affecting autooxidation, we found the rate of autooxidation for both quercetin and myricetin to be highly pH dependent with no autooxidation detected for quercetin at physiologic pH. Both the addition of iron for the two flavonols and the addition ofiron followed by SOD for quercetin increased the rate of autooxidation substantially. Neither kaempferol, a monohydroxylated flavonol nor rutin, a glycosylated quercetin showed any ability to autooxidize. The results with rutin differ from what we expected based on the B-ring structural similarity to quercetin.
Publisher Summary There are a number of procedures, for example, chemical, enzymatic, and chromatographic for the determination of glutathione (GSH) and glutathione disulfide (GSSG) in biological samples. Enzymatic and chromatographic methods for the determination of glutathione in biological samples are described in this chapter. Because GSH readily oxidizes nonenzymatically and because it is a good substrate of γ-glutamyl transpeptidase, the biological samples are acidified quickly to reduce oxidation of GSH to GSSG and to mixed disulfides, and to inactivate γ-glutamyl transpeptidase. Glutathione oxidizes rapidly at pH values greater than 7. Acid treatment inactivates γ-glutamyl transpeptidase, which catalyzes the reactions that decrease the levels of both GSH and GSSG. The optimum method for treating biological samples depends upon the tissue and the experimental system. The discussed 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB)-GSSG reductase recycling assay for total glutathione is a specific, sensitive, rapid, and reliable procedure. However, because the method depends on an accurate standard curve, appropriate standards containing the protein precipitating agent are essential.
An assay was devised to quantitate acute intestinal inflammation based on the assessment of myeloperoxidase activity. Myeloperoxidase is an enzyme found in neutrophils and, in much smaller quantities, in monocytes and macrophages. Myeloperoxidase was solubilized with hexadecyltrimethylammonium bromide and myeloperoxidase activity was measured with a dianisidine-H2O2 assay. In neutrophil suspensions, myeloperoxidase activity was directly related to cell number down to as few as 500 cells. Myeloperoxidase activity was assayed in two animal models of inflammation: acetic acid-induced colitis in rats and Clostridium difficile enterotoxin-induced enteritis in hamsters. In both models, the activity of myeloperoxidase solubilized from the inflamed tissue was directly proportional to the number of neutrophils seen in histologic sections. Histologic evaluation of neutrophil accumulation was performed by counting the number of neutrophils in a histologic section 0.18 mm long and 5 micron thick. In both animal models, myeloperoxidase activity was linearly related to neutrophil number from 400 and 4000 cells/mm. Myeloperoxidase activity from chronically inflamed colon, in which both neutrophils and histiocytes were present, was directly related to neutrophil content. Histiocytes did not contribute significantly to myeloperoxidase activity. The determination of myeloperoxidase activity in the intestine is a simple biochemical assay that can be used to quantitate inflammation.
Leukotriene B4, an arachidonic acid metabolite, is a potent chemotactic agent, and is thought to be an important mediator of inflammation. To investigate the role of this compound as a mediator of inflammation in inflammatory bowel disease, arachidonic acid was incubated with ionophore and colonic mucosa from patients with inflammatory bowel disease and from normal subjects. Mucosa from patients with inflammatory bowel disease converted 2.17% of exogenous arachidonate to leukotriene B4; mucosa from normal subjects converted 0.37%. The production of leukotriene was blocked by sulfasalazine. To determine if inflammatory bowel mucosa contained endogenous leukotriene B4, lipid extracts were analyzed by high pressure liquid chromatography. Mucosa from patients with inflammatory bowel disease contained 254 ng of leukotriene B4 per gram and mucosa from normal subjects contained less than 5 ng of leukotriene B4 per gram. The presence of significant amounts of leukotriene B4 in colonic mucosa in patients with inflammatory bowel disease, combined with the known biologic effects of leukotriene B4, suggests that it may be an important mediator of inflammation in inflammatory bowel disease.
1. Endotoxin induces nitric oxide synthase in vascular tissue, including rat main pulmonary artery. Currently available agents that cause inhibition of nitric oxide synthase are relatively non-selective between the constitutive and inducible forms of the enzyme. 2. Aminoguanidine caused a dose-dependent increase in phenylephrine-induced tension in intact and endothelium-denuded pulmonary artery rings from endotoxin-treated rats, but had no effect on sham-treated controls. 3. Contraction caused by aminoguanidine in endothelium-denuded vessels from endotoxin-treated rats was unaffected by indomethacin (10 microM), and by cimetidine and mepyramine (both 10 microM), excluding an effect of aminoguanidine mediated by arachidonic acid metabolites or histamine. 4. Contraction caused by aminoguanidine in endothelium-denuded vessels from endotoxin-treated rats was abolished by L-arginine (2 mM) and L-NG-monomethyl arginine (300 microM), but unaffected by D-arginine and D-NG-monomethyl arginine, suggesting that its action is mediated by the L-arginine/nitric oxide pathway. 5. Aminoguanidine had no effect on acetylcholine-induced relaxation of intact vessels from shamtreated rats. However, relaxation of artery rings from endotoxin-treated rats by L-arginine was competitively inhibited by aminoguanidine.6. These results in isolated main pulmonary arteries of the rat confirm previous reports that aminoguanidine is a selective inhibitor of inducible nitric oxide synthase.
We investigated the involvement of nitric oxide in trinitrobenzene-sulfonic acid (TNB) colitis. Every 24 h after TNB, rats were orally dosed with NG-nitro-L-arginine methyl ester (L-NAME; 30 mg/kg), NG-nitro-D-arginine methyl ester (D-NAME), or water, and food intake, body weight, and plasma nitrite levels were measured. On day 6, colonic nitric oxide synthase and myeloperoxidase (MPO) activity, histology, intestinal muscle growth, NADPH-diaphorase, and myenteric nerve function were assessed. Food intake and body weight were reduced during the first 72 h of colitis. On day 6 post-TNB, a fourfold increase in mucosal nitric oxide synthase, a 30-fold increase in MPO, and a fivefold elevation in plasma nitrite were measured. Smooth muscle hyperplasia and hypertrophy in both colonic muscle layers, numerous diaphorase-positive macrophages in the myenteric plexus, and a suppression of myenteric nerve function were also observed. Unlike D-NAME, oral L-NAME reduced MPO and intestinal muscle hyperplasia by > 90%. Likewise, plasma nitrite and colonic nitric oxide synthase were reduced by > 70%. L-NAME completely prevented macrophage infiltration into the muscle. Conversely, it had no effect on anorexia or intestinal smooth muscle hypertrophy, nor did it affect suppressed myenteric nerve neurotransmitter release. These results demonstrate the selective transmural protective effects of L-NAME in the inflamed colon, implicating nitric oxide as a mediator.
Enhanced nitric oxide (NO) generation by stimulated NO synthase (NOS) activity may, through its oxidative metabolism contribute to tissue injury in experimental colitis. In this study the possible amelioration of experimental colitis by NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NOS activity, was evaluated. Colitis was induced in rats by intracolonic administration of 30 mg trinitrobenzene sulphonic acid (TNB) dissolved in 0.25 ml 50% ethanol or by flushing the colon of capsaicin pretreated rats with 2 ml of 5% acetic acid. In several experiments, L-NAME 0.1 mg/ml was added to the drinking water at the time of colitis induction with TNB or seven days before acetic acid treatment. Rats were killed at various time intervals after induction of colitis. A 10 cm distal colonic segment was isolated, weighed, lesion area measured, and explants organ cultured for 24 hours for determination of NO generation by the Greiss reaction. The rest of the mucosa was scraped for determination of myeloperoxidase and NOS activities and leukotriene generation. In TNB treated rats mean arterial pressure was also determined up to 72 hours after damage induction, with or without cotreatment with nitroprusside. L-NAME significantly decreased the extent of tissue injury in TNB treated rats. Seven days after TNB treatment lesion area was reduced by 55%, colonic weight by 37%, and myeloperoxidase and NOS activity by 59% and 42%, respectively. Acetic acid induced colitis in capsaicin pretreated rats was also significantly decreased by L-NAME. Twenty four hours after acetic acid treatment lesion area was reduced by 61%, colonic weight by 21% and NOS activity by 39%. Mean (SEM) arterial blood pressure in TNB+L-NAME treated rats was 37.6 (8.1) mm Hg higher than in TNB treated rats, an effect that was only partially abolished by nitroprusside. These results show that inhibition of NO synthesis by an L-arginine analogue significantly ameliorates the extent of tissue injury in two models of experimental colitis, an effect that is not due only to its vasoconstrictor properties. Modulation of NO generation may be a novel therapeutic approach in inflammatory bowel disease.
Delivery of 5-aminosalicylic acid to the colon by sulphasalazine, other azo-bonded compounds and controlled-release preparations is introduced in the context of metabolism by epithelial cells and therapeutic efficacy in ulcerative colitis. Potential modes of action are then reviewed, including actions on luminal bacteria, epithelial cell surface receptors, cellular events (such as nitric oxide release or butyrate oxidation), electrolyte transport and epithelial permeability. Evidence for an influence of salicylates on circulating and lamina propria inflammatory cells is presented, as well as actions on adhesion molecules, chemotactic peptides and inflammatory mediators, such as eicosanoids, platelet-activating factor, cytokines or reactive oxygen metabolites. The precise mechanism will remain uncertain as long as the aetiology of ulcerative colitis is unknown, but a pluripotential mode of action of salicylates is an advantage when influencing the network of events that constitute chronic inflammation.
The effect of BPC-15 (Booly Protection Compound-15) was evaluated in a rat model of colonic injury. A single intracolonic administration of trinitrobenzene sulfonic acid (TNBS) dissolved in ethanol induces severe colonic damage, which is characterized by areas of necrosis surrounded by areas of acute inflammation. The damage is associated with high myeloperoxidase (MPO) activity, mainly as a reflection of neutrophilic infiltration into the damaged tissue. In this study, 1 hr before a single intracolonic administration of 50 mg/kg of TNBS in 50% ethanol, the animals were treated with one of the following doses of BPC-15: 0.0001, 0.001, 0.01, 0.1, 1 or 10 nmol/kg administered i.p. or with a dose of 10 nmol/kg administered intracolonically. The animals were sacrificed 3 days later and the extent of colonic necrosis and hyperemia was measured with an image analyzer. The i.p. administration of BPC-15 significantly reduced the extent of TNBS-induced colonic damage in a dose-dependent manner. This was associated with a statistically significant and dose-dependent reduction in colonic tissue MPO activity. At the dose tested (10 nmol/kg), intracolonic administration of BPC-15 did not significantly reduce either the extent of the colonic damage or the increase in MPO activity induced by TNBS. In conclusion, this study showed that i.p. administration of BPC-15 reduced TNBS-induced colonic damage in rats.
We undertook this study in order to fully characterize the clinical and histopathology features of the dextran sulfate sodium (DSS) model of experimental murine colitis and to discover the earliest histopathologic changes that lead to colitis.
Acute colitis was induced in Swiss-Webster mice by 7 days of oral DSS with animals sacrificed daily. Chronic colitis was induced by: (a) 7 days of oral DSS followed by 7 days of H2O (for 1, 2, and 3 cycles) and (b) 7 days of oral DSS followed by 14 and 21 days of H2O. In each experimental group, the entire colons were examined histologically and correlated with clinical symptoms.
Acute clinical symptoms (diarrhea and/or grossly bloody stool) were associated with the presence of erosions and inflammation. More importantly, the earliest histologic changes which predated clinical colitis was loss of the basal one-third of the crypt (day 3), which progressed with time to loss of the entire crypt resulting in erosions on day 5. The earliest changes were very focal and not associated with inflammation. Inflammation was a secondary phenomena and only became significant after erosions appeared. Animals treated with only 7 days of DSS followed by 14 and 21 days of H2O developed a chronic colitis with the following histologic features: areas of activity (erosions and inflammation), inactivity, crypt distortion, florid epithelial proliferation and possible dysplasia. These changes were similar to animals given 3 cycles of DSS. The clinical disease activity index correlated significantly with pathologic changes in both the acute and chronic phases of the disease.
The mechanism of DSS colitis is presently unknown. However, the finding of crypt loss without proceeding or accompanying inflammation suggests that the initial insult is at the level of the epithelial cell with inflammation being a secondary phenomena. This may be a good model to study how early mucosal changes lead to inflammation and the biology of the colonic enterocyte. Chronic colitis induced after only 7 days of DSS may serve as a useful model to study the effects of pharmacologic agents in human inflammatory disease and mechanisms of perpetuation of inflammation. Finally, we believe that this model has the potential to study the dysplasia cancer sequence in inflammatory disease.
The transcription factor NF-kappa B has attracted widespread attention among researchers in many fields based on the following: its unusual and rapid regulation, the wide range of genes that it controls, its central role in immunological processes, the complexity of its subunits, and its apparent involvement in several diseases. A primary level of control for NF-kappa B is through interactions with an inhibitor protein called I kappa B. Recent evidence confirms the existence of multiple forms of I kappa B that appear to regulate NF-kappa B by distinct mechanisms. NF-kappa B can be activated by exposure of cells to LPS or inflammatory cytokines such as TNF or IL-1, viral infection or expression of certain viral gene products, UV irradiation, B or T cell activation, and by other physiological and nonphysiological stimuli. Activation of NF-kappa B to move into the nucleus is controlled by the targeted phosphorylation and subsequent degradation of I kappa B. Exciting new research has elaborated several important and unexpected findings that explain mechanisms involved in the activation of NF-kappa B. In the nucleus, NF-kappa B dimers bind to target DNA elements and activate transcription of genes encoding proteins involved with immune or inflammation responses and with cell growth control. Recent data provide evidence that NF-kappa B is constitutively active in several cell types, potentially playing unexpected roles in regulation of gene expression. In addition to advances in describing the mechanisms of NF-kappa B activation, excitement in NF-kappa B research has been generated by the first report of a crystal structure for one form of NF-kappa B, the first gene knockout studies for different forms of NF-kB and of I kappa B, and the implications for therapies of diseases thought to involve the inappropriate activation of NF-kappa B.
Quercitrin was tested for acute and chronic anti-inflammatory activity in trinitrobenzenesulfonic acid-induced rat colitis. The inflammatory status was evaluated by myeloperoxidase, alkaline phosphatase and total glutathione levels, leukotriene B4 synthesis, in vivo colonic fluid absorption, macroscopical damage and occurrence of diarrhea and adhesions. Treatment with 1 or 5 mg/kg of quercitrin by the oral route reduced myeloperoxidase and alkaline phosphatase levels, preserved normal fluid absorption, counteracted glutathione depletion and ameliorated colonic damage at 2 days. Increasing or lowering the dose of the flavonoid resulted in marked loss of effect. The acute anti-inflammatory effect of quercitrin is unrelated to impairment of neutrophil function or lipoxygenase inhibition, and it may be caused by mucosal protection or enhancement of mucosal repair secondary to increased defense against oxidative insult and/or preservation of normal colonic absorptive function. When tested in chronic colitis (2 and 4 weeks), quercitrin treatment (1 or 5 mg/kg.day) decreased colonic damage score and the incidence of diarrhea, and normalized the colonic fluid transport. All other parameters were unaffected. The chronic effect of the flavonoid is apparently related to its action on colonic absorption, although it can be partly secondary to its acute beneficial effect.
Glucocorticoids inhibit the expression and action of most cytokines. This is part of the in vivo feed-back system between inflammation-derived cytokines and CNS-adrenal produced corticosteroids with the probable physiological relevance to balance parts of the host defence and anti-inflammatory systems of the body. Glucocorticoids modulate cytokine expression by a combination of genomic mechanisms. The activated glucocorticoid-receptor complex can (i) bind to and inactivate key proinflammatory transcription factors (e.g. AP-1, NF kappa B). This takes place at the promotor responsive elements of these factors, but has also been reported without the presence of DNA; (ii) via glucocorticoid responsive elements (GRE), upregulate the expression of cytokine inhibitory proteins, e.g. I kappa B, which inactivates the transcription factor NF kappa B and thereby the secondary expression of a series of cytokines; (iii) reduce the half-life time and utility of cytokine mRNAs. In studies with triggered human blood mononuclear cells in culture, glucocorticoids strongly diminish the production of the 'initial phase' cytokines IL-1 beta and TNF-alpha and the 'immunomodulatory' cytokines IL-2, IL-3, IL-4, IL-5, IL-10, IL-12 and IFN-gamma, as well as of IL-6, IL-8 and the growth factor GM-CSF. While steroid treatment broadly attenuates cytokine production, it cannot modulate it selectively, e.g. just the TH0, the TH1 or the TH2 pathways. The production of the 'anti-inflammatory' IL-10 is also inhibited. The exceptions of steroid down-regulatory activity on cytokine expression seem to affect 'repair phase' cytokines like TGF-beta and PDGF. These are even reported to be upregulated, which may explain the rather weak steroid dampening action on healing and fibrotic processes. Some growth factors, e.g. G-CSF and M-CSF, are only weakly affected. In addition to diminishing the production of a cytokine, steroids can also often inhibit its subsequent actions. Because cytokines work in cascades, this means that steroid treatment can block expression of the subsequent cytokines. The blocked cytokine activity does not depend on a reduced cytokine receptor expression; in fact available in vitro investigations show that while the cytokine expression is blunted, its receptor is upregulated. The cellular studies presented here may represent the maximum potential of steroids to modulate cytokine expression in human mononuclear cells. It remains to be determined by clinical-experimental studies how effective cytokine modulation can be achieved in situ in inflamed bowel by systemic or by topical steroid therapy. Such studies may also answer whether a blocked cytokine production/action is the key or just a secondary mechanism behind the unique efficacy of steroids in active inflammatory bowel disease.
The effect of the flavonoid rutoside on acetic acid-induced rat colitis was studied. Rats were pretreated orally with different doses of the flavonoid (10, 25, and 100 mg/kg) 48, 24, and 1 hour prior to colitis induction and examined for colonic damage 24 hours later. Colonic inflammation was characterized by gross and microscopical injury, bowel wall thickening, abolition of fluid absorption, glutathione depletion, enhanced leukotriene B4 synthesis, and increased levels of myeloperoxidase and alkaline phosphatase activities. Rutoside treatment (25 and 100 mg/kg) reduced histologic injury and prevented the increase in alkaline phosphatase activity, but it had no effect on myeloperoxidase levels or leukotriene B4 synthesis. In addition, glutathione depletion was effectively counteracted at the dose of 25 mg/kg, whereas fluid absorption was achieved at the highest dose assayed. It is concluded that rutoside has an acute anti-inflammatory activity in this model which may be related to a putative direct protective effect on intestinal cells, mainly enterocytes, in which the antioxidative properties of the flavonoid may play a role.
Rutoside, a flavonoid with antioxidant properties, was tested for acute and chronic antiinflammatory activity in trinitrobenzenesulfonic acid-induced rat colitis. Pretreatment with 10 or 25 mg/kg of rutoside by the oral route reduced colonic damage at 2 days. Several mechanisms can be involved in this activity, and one of these may be related to its ability in preventing glutathione depletion of colitic animals, and this could result in mucosal protection against oxidative insult. When rutoside was tested for 1 and 2 weeks after colitis induction, it was able to promote colonic healing. The chronic effect of the flavonoid was also related with its ability to increase colonic glutathione levels and thus reduce the tissue damage derived from intestinal oxidative stress which characterizes inflammatory colitis.
Although there have been numerous topical applications of plant extracts having flavonoids known as anti-inflammatory compounds, only a few studies were reported concerning effects of flavonoids on epidermal cyclooxygenase/lipoxygenase. In this investigation, effects of naturally occurring flavonoids on epidermal cyclooxygenase/lipoxygenase were studied using five selected derivatives: flavanone, apigenin (flavone), quercetin (flavonol), amentoflavone and ginkgetin (biflavone) because eicosanoids generated in the epidermis are believed to be involved in various biological activities of the skin. Microsomal and cytosolic fractions were obtained from guinea-pig epidermal homogenate by centrifugation and used as a source for cyclooxygenase and lipoxygenase. It was found that quercetin inhibited both cyclooxygenase and lipoxygenase, being more potent against lipoxygenase, while flavanone and apigenin did not show any inhibition. Amentoflavone, one of the biflavones tested, showed potent and selective inhibitory activity on cyclooxygenase (IC50 = 3 microM) which was comparable to indomethacin (IC50 = 1 microM). In contrast, structurally similar ginkgetin possessed weak inhibitory activity on cyclooxygenase. The in vivo effects of these flavonoids on the normal and diseased skin remain to be studied.
Resveratrol, naringenin and naringin are naturally occurring flavonoids in grapes and grapefruits. The anti-inflammatory effects of these flavonoids have been well documented, but the mechanism is poorly characterized. High concentration of NO are produced by inducible NO synthase (iNOS) in inflammation, and the prevention of the expression of iNOS may be an important anti-inflammatory mechanism. In this study, the effects of these flavonoids on the induction of NO synthase (NOS) in RAW 264.7 cells activated with bacterial lipopolysaccharide (LPS, 50 ng ml−1) were investigated.
Resveratrol was found strongly to inhibit NO generation in activated macrophages, as measured by the amount of nitrite released into the culture medium, and resveratrol strongly reduced the amount of cytosolic iNOS protein and steady state mRNA levels. However, the inhibitory abilities of naringenin were lower, and the inhibitory abilities of naringin were almost negligible.
In electrophoretic mobility shift assays, the activation of NFκB induced by LPS for 1 h was inhibited by resveratrol (30 μM). Furthermore, in immunoblotting analysis, cells treated with LPS plus resveratrol showed an inhibition of phosphorylation as well as degradation of IκBα, and a reduced nuclear content of NFκB subunits.
The flavonoids may be of value for inhibiting the enhanced expression of iNOS in inflammation through down-regulation of NFκB binding activity.
British Journal of Pharmacology (1999) 126, 673–680; doi:10.1038/sj.bjp.0702357
Excess nitric oxide formation caused by the activity of the inducible nitric oxide synthase has been implicated as a toxic effector molecule in the pathogenesis of experimental colitis and inflammatory bowel disease. It was therefore investigated whether inhibition of this synthase or the cytokines TNF and IFN-gamma, inducers of nitric oxide synthase, had effects on chronic colitis in mice. Chronic colitis was induced in mice by repeated feeding of DSS. Cytokines were neutralized by treatment with MoAbs and nitric oxide synthase was inhibited by aminoguanidine. The degree of colonic inflammation was assessed by a histological score and colon length. Aminoguanidine treatment reduced nitric oxide activity by 60% (P = 0. 0004), the histological score by 31% (P = 0.005) and increased colon length by 1.4 cm (P = 0.002). Neutralization of TNF and IFN-gamma resulted in increased colon length (0.7 cm, P = 0.07 and 0.8 cm, P = 0.03), improved histological score (19%, P = 0.045 and 25%, P = 0. 013), and reduced nitric oxide activity (31%, P = 0.07 and 54%, P = 0.004) compared with controls. The combination of anti-cytokine treatments had additive effects. TNF and IFN-gamma are involved in perpetuation of chronic DSS-induced colitis, and induction of excessive nitric oxide activity could be their common effector mechanism.
Flavonoids affect the inflammatory process of the mammalian system and possess anti-inflammatory as well as immunomodulatory activities in vitro and in vivo. Since nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) is one of the inflammatory mediators, the effects of various naturally occurring flavonoids on NO production in LPS-activated RAW 264.7 cells were evaluated in vitro. Flavonoids such as apigenin, wogonin, luteolin, tectorigenin, and quercetin inhibited NO production, as measured by nitrite formation at 10-100 microM. The most active among 26 flavonoid derivatives tested were apigenin, wogonin, and luteolin, having IC50 values of 23, 17, and 27 microM, respectively, while AMT, a synthetic selective iNOS inhibitor, had an IC50 value of 0.09 microM. In contrast, flavanones, such as naringenin, and flavonoid glycosides, such as apiin, did not demonstrate significant inhibition up to 100 microM. These results clearly indicated that a C-2,3 double bond might be important, and that the potency of inhibition depended upon the substitution patterns of the flavonoid molecules. The inhibitory activity of flavonoids was not due to direct inhibition of iNOS enzyme activity because they did not reasonably inhibit iNOS activity, as measured by [3H]citrulline formation from [3H]arginine, up to 100 microM. In contrast, wogonin and luteolin concentration-dependently reduced iNOS enzyme expression, when measured by western blotting, at 10-100 microM. All these results clearly demonstrated that certain flavonoids inhibit NO production in lipopolysaccharide-activated RAW 264.7 cells, and their inhibitory activity might be due to reduction of iNOS enzyme expression.
Trinitrobenzene sulfonic acid (TNBS)-induced colitis is a T-helper 1 (Th1) T cell-mediated inflammation that is rapidly reversed by administration of anti-interleukin (IL) 12. This study sought to define the mechanism of this curative effect.
Cells and tissue from mice with TNBS colitis receiving treatment with anticytokines were analyzed for phenotype, cytokine production, and apoptosis.
In initial studies, we found that treatment of mice with TNBS-induced colitis with anti-IL-12 was more effective than with anti-interferon (IFN)-gamma, and that anti-IL-12 led to complete normalization of IFN-gamma production by lamina propria T cells ex vivo, whereas anti-IFN-gamma did not. These data suggesting that anti-IL-12 leads to reversal of colitis by elimination of the Th1 T cells were substantiated by studies showing that anti-IL-12 treatment led to increased numbers of apoptotic cells in the lamina propria and spleen by both TUNEL staining of tissues and dispersed spleen cell populations. Finally, we found that the observed apoptosis was mediated by the Fas pathway because (1) MRL/MpJ-lpr(fas) mice lacking Fas function develop colitis that responds poorly to treatment with anti-IL-12; and (2) SJL/J mice with TNBS colitis that received Fas-Fc to block the Fas pathway were resistant to anti-IL-12 treatment.
These studies show that a main mechanism of action of anti-IL-12 in TNBS-induced colitis is the induction of Fas-mediated apoptosis of the Th1 T cells, causing inflammation.
The intestinal anti-inflammatory activity of two flavonoids, hesperidin and diosmin, was evaluated in the acute stage of the trinitrobenzenesulfonic acid (TNBS) model of rat colitis. The results obtained showed that pretreatment with diosmin (10 mg/kg) or hesperidin (10 and 25 mg/kg) reduced colonic damage compared to TNBS control rats. This effect was confirmed biochemically by a reduction in colonic myeloperoxidase activity compared to non-treated colitic animals. Colonic glutathione levels in colitic animals were significantly increased after hesperidin or diosmin treatment. Diosmin decreased colonic MDA production and inhibited LTB4 synthesis, whereas hesperidin failed to do so. Conversely, only hesperidin improved colonic fluid absorption, which was impaired in colitic animals. In conclusion, both diosmin and hesperidin were able to prevent colonic inflammation, acting via a mechanism in which protection against oxidative insult may play a role.
Despite limited understanding of therapeutic aetiopathogenesis of ulcerative colitis and Crohn’s disease, there is a strong evidence base for the efficacy of pharmacological and biological therapies. It is equally important to recognise toxicity of the medical armamentarium for inflammatory bowel disease (IBD).
Sulfasalazine consists of sulfapyridine linked to 5-aminosalicylic acid (5-ASA) via an azo bond. Common adverse effects related to sulfapyridine ‘intolerance’ include headache, nausea, anorexia, and malaise. Other allergic or toxic adverse effects include fever, rash, haemolytic anaemia, hepatitis, pancreatitis, paradoxical worsening of colitis, and reversible sperm abnormalities.
The newer 5-ASA agents were developed to deliver the active ingredient of sulfasalazine while minimising adverse effects. Adverse effects are infrequent but may include nausea, dyspepsia and headache. Olsalazine may cause a secretory diarrhoea. Uncommon hypersensitivity reactions, including worsening of colitis, pancreatitis, pericarditis and nephritis, have also been reported.
Corticosteroids are commonly prescribed for treatment of moderate to severe IBD. Despite short term efficacy, corticosteroids have numerous adverse effects that preclude their long term use. Adverse effects include acne, fluid retention, fat redistribution, hypertension, hyperglycaemia, psycho-neurological disturbances, cataracts, adrenal suppression, growth failure in children, and osteonecrosis. Newer corticosteroid preparations offer potential for targeted therapy and less corticosteroid-related adverse effects.
Azathioprine and mercaptopurine are associated with pancreatitis in 3 to 15% of patients that resolves upon drug cessation. Bone marrow suppression is dose related and may be delayed.
The adverse effects of methotrexate include nausea, leucopenia and, rarely, hypersensitivity pneumonia or hepatic fibrosis. Common adverse effects of cyclosporin include nephrotoxicity, hypertension, headache, gingival hyperplasia, hyperkalaemia, paresthesias, and tremors. These adverse effects usually abate with dose reduction or cessation of therapy. Seizures and opportunistic infections have also been reported.
Antibacterials are commonly employed as primary therapy for Crohn’s disease. Common adverse effects of metronidazole include nausea and a metallic taste. Peripheral neuropathy can occur with prolonged administration. Ciprofloxacin and other antibacterials may be beneficial in those intolerant to metronidazole.
Newer immunosuppressive agents previously reserved for transplant recipients are under investigation for IBD. Tacrolimus has an adverse effect profile similar to cyclosporin, and may cause renal insufficiency. Mycophenolate mofetil, a purine synthesis inhibitor, has primarily gastrointestinal adverse effects.
Biological agents targeting specific sites in the immunoinflammatory cascade are now available to treat IBD. Infliximab, a chimeric antibody targeting tumour necrosis factor-α has been well tolerated in clinical trials and early postmarketing experience. Additional trials are needed to assess long term adverse effects.
Although substance P (SP) has been implicated as a mediator of neurogenic inflammation in the small intestine, little information is available regarding the role of SP in the pathogenesis of chronic ulcerative colitis. In this study, our aim was to investigate whether the intraperitoneal administration of a nonpeptide neurokinin-1 (NK-1) antagonist, CP-96345, which antagonizes the binding of SP to its NK-1 receptor, results in the attenuation of colonic inflammation induced in rats by 5% dextran sodium sulfate (DSS) in drinking water for 10 days compared with an inactive enantiomer, CP-96344. Disease activity was assessed daily for 10 days, after which colonic tissue damage was scored and myeloperoxidase activity and colon and urinary 8-isoprostanes were measured. Animals receiving DSS exhibited marked physical signs of colitis by day 5 compared with controls. Chronic administration of the NK-1 antagonist significantly reduced the disease activity index, mucosal myeloperoxidase activity, colonic tissue damage score, and mucosal and urinary levels of 8-isoprostanes compared with inactive enantiomer- or vehicle-injected (saline) animals receiving DSS alone. These data indicate that the administration of an NK-1 antagonist can attenuate colonic inflammation and oxidative stress and suggest a novel therapeutic approach in the treatment of chronic ulcerative colitis.
Chronic inflammatory bowel disease (IBD) refers to two diseases: Crohn's disease (CD) and ulcerative colitis (UC). The etiology of IBD remains unknown. The understanding of the pathogenesis has expanded greatly over the last decade. The combination of genetic risk factors, abnormalities in the immune system, vascular and neural factors, and random environmental factors may all play an important role. Most treatments currently in use have multiple action. The choice of appropriate medical treatment is determined by the status (inductive or maintenance therapy) and severity of the disease and the potential for toxicity. Despite the variety of medical therapies available for the treatment of IBD, none is ideal. Ongoing research into the well-established drugs, as well as novel agents with more precise targets, may contribute to an optimal therapy of IBD in the near future. In this paper the current (5-aminosalicylates, glucocorticosteroids, thioguanine derivatives, methotrexate, cyclosporin and infliximab) as well as some of the new (mycophenolate mofetil and thalidomide) therapeutic options are reviewed.
Morin, a bioflavonoid with antioxidant properties, shows intestinal anti-inflammatory activity in the acute phase of the trinitrobenzenesulphonic acid model of rat colitis.
To assess the anti-inflammatory activity of morin in the chronic stages of trinitrobenzenesulphonic acid-induced rat colitis.
Rats were rendered colitic by a single colonic instillation of 30 mg of the hapten trinitrobenzenesulphonic acid dissolved in 0.25 mL of 50% ethanol. A group of colitic animals was given morin orally at doses of 25 mg/kg daily. Animals were sacrificed every week for 4 weeks. Colonic damage was evaluated macroscopically and microscopically. Different biochemical markers of colonic inflammation were also assayed, including myeloperoxidase activity, leukotriene B4 and interleukin-1beta synthesis, glutathione and malonyldialdehyde levels and nitric oxide synthase activity.
The administration of morin facilitated tissue recovery during the 4 weeks following colonic insult with trinitrobenzenesulphonic acid, as demonstrated macroscopically and microscopically, as well as biochemically by a reduction in myeloperoxidase activity. The intestinal anti-inflammatory effect of morin was accompanied by a significant reduction in colonic leukotriene B4 and interleukin-1beta levels, improvement in colonic oxidative stress and inhibition of colonic nitric oxide synthase activity.
Morin exerts a beneficial anti-inflammatory effect in the chronic phase of trinitrobenzenesulphonic acid-induced rat colitis through the down-regulation of some of the mediators involved in the intestinal inflammatory response, including free radicals, cytokines, leukotriene B4 and nitric oxide.
Quercitrin is a flavonoid with antiinflammatory activity in experimental colitis, associated with an antioxidative action and amelioration of water absorption in vivo. However, its mechanism of action is unclear. This study focuses on the effect of quercitrin (1 and 5 mg/kg) in the early stages (24 h) of trinitrobenzene sulfonic acid colitis. Treatment with the flavonoid prevented the increase in colonic malondialdehyde and inhibited nitric oxide synthase and alkaline phosphatase activity but had no significant effects on observable damage. No effect on neutrophil infiltration (myeloperoxidase) was observed. On the other hand, quercitrin exerted complex effects on colonic hydroelectrolytic transport, showing a slight potentiation of water absorption in vivo (5 mg/kg) as well as a normalization of carbachol stimulated electrogenic ionic transport in the proximal colon in vitro (5 mg/kg). It is concluded that the beneficial effects of quercitrin on trinitrobenzene sulfonic acid chronic colitis arise from an early downregulation of the inflammatory cascade that is associated with amelioration of the disturbances in hydroelectrolytic transport.
One of the most consistent and dramatic findings in both experimental and human inflammatory bowel disease (e.g., Crohn's disease, ulcerative colitis) is the enhanced expression of the inducible isoform of nitric oxide synthase (iNOS) and the sustained overproduction of the free radical nitric oxide (NO). The role that iNOS-derived NO plays in the pathophysiology of inflammatory bowel disease remains the subject of intense investigation and active debate. Although several different studies using a variety of animal models of acute and chronic gut inflammation suggest that NO may promote intestinal inflammation, an equally impressive number of investigations suggest that iNOS may play no role or may act to attenuate or to limit the extent of inflammatory tissue injury. This review discusses some of the basic concepts related to the immunoregulation of chronic gut inflammation and summarizes the current state of knowledge of the role that NO may play in modulating inflammatory tissue injury.