Inflammation may increase cancer risk, therefore, we studied whether polyphenol-rich Marie Ménard (MM) apples with reported anti-inflammatory activity prevent 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis in rats and, likewise whether high-fat (HF) diet promoting carcinogenesis, may affect inflammation. DMH-induced rats were fed for 15 weeks with: an HF diet (23% corn oil w/w); an HF diet containing 7.6% w/w lyophilized MM (apple diet (AD)); a low-fat (LF) diet and an HF diet containing piroxicam (PXC) (0.01% w/w) as control. Mucin depleted foci (MDF), precancerous lesions in the colon, were dramatically reduced in the AD, LF, and PXC groups compared with the HF. Peritoneal macrophage activation, an index of systemic inflammation, was significantly decreased in the AD, LF, and PXC groups. TNF-α, iNOS, IL-1β, IL-6 m-RNA expression in the colon, as well as CD68 cells and plasmatic PGE2 were lower in the AD, but not in the LF group. Apoptosis in the MDF of both the AD and LF-fed rats was significantly higher than in HF rats. In conclusion, AD has a strong chemopreventive effect, reducing inflammation, and increasing apoptosis, while the chemopreventive effect of the LF diet seems mediated mainly by increased apoptosis in MDF.
Fatty acid esters of 3-chloropropane-1,2-diol (3-MCPD) and glycidol are a newly identified class of food process contaminants. They are widespread in refined vegetable oils and fats and have been detected in vegetable fat-containing products, including infant formulas. There are no toxicological data available yet on the 3-MCPD and glycidol esters, and the primary toxicological concern is based on the potential release of 3-MCPD or glycidol from the parent esters by lipase-catalyzed hydrolysis in the gastrointestinal tract. Although 3-MCPD is assessed as a nongenotoxic carcinogen with a tolerable daily intake (TDI) of 2 μg/kg body weight (bw), glycidol is a known genotoxic carcinogen, which induces tumors in numerous organs of rodents. The initial exposure estimates, conducted by Federal Institute for Risk Assessment (BfR) under the assumption that 100% of the 3-MPCD and glycidol are released from their esters, revealed especially that infants being fed commercial infant formula could ingest harmful amounts of 3-MCPD and glycidol. However, the real oral bioavailability may be lower. As this gives rise for toxicological concern, the currently available toxicological data of 3-MCPD and glycidol and their esters are summarized in this review and discussed with regard to data gaps and further research needs.
In recent years, there has been a growing body of evidence pointing to an effect of vitamin D on muscle mass and function. Our aim was to investigate the combined effect of 1,25(OH)2 -vitamin D3 (1,25(OH)2 D3 ) with anabolic factors insulin and leucine on protein fractional synthesis rate (FSR) and regulation in the mouse C2C12 myotube.
After differentiation, myotubes were cultured in 1,25(OH)2 D3 solutions at 0, 1, or 10 nM for 72 h. Cells were treated by l-[1-(13) C]valine and puromycin in presence or not of leucine and insulin, and protein FSR was determined by measuring tracer enrichments and puromycin incorporation in proteins, respectively. Protein expression and phosphorylation state of insulin receptor (IR), Akt, GSK3, mTOR, p70 S6 kinase, rpS6, and 4EBP1 were measured by Western blot. Transcript levels of IR and 1,25(OH)2 D3 receptor (VDR) were determined by qPCR. 1,25(OH)2 D3 (10 nM) with leucine and insulin increased protein FSR in C2C12 myotubes (14-16%). IR and VDR mRNA expression was increased with 1,25(OH)2 D3 treatment. The Akt/mTOR-dependent pathway was activated by insulin and leucine and further enhanced by 1,25(OH)2 D3 .
1,25(OH)2 D3 sensitizes the Akt/mTOR-dependant pathway to the stimulating effect of leucine and insulin, resulting in a further activation of protein synthesis in murine C2C12 skeletal myotubes.
1,6-O,O-diacetylbritannilactone (OODBL) isolated from Inula britannica, exhibits potent antitumor activity against several human cancer cell lines. However, the molecular mechanism of OODBL in the induction of anticancer activity is still unclear. In the present study, we demonstrated that OODBL induced the occurrence of apoptosis in human leukemic (HL-60) cells and cell arrest at the S phase. On the other hand, activation of caspase-8, -9, and -3, phosphorylation of Bcl-2 and Bid, and increased release of cytochrome c from mitochondria into cytosolic fraction were detected in OODBL-treated HL-60 cells. We further demonstrated that production of reactive oxygen species (ROS), activation of mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) signaling pathways may play an important role in OODBL-induced apoptosis. The results from the present study highlight the molecular mechanisms underlying OODBL-induced anticancer activity.
The metabolism of 1,8-cineole after ingestion of sage tea was studied. After application of the tea, the metabolites 2-hydroxy-1,8-cineole, 3-hydroxy-1,8-cineole, 9-hydroxy-1,8-cineole and, for the first time in humans, 7-hydroxy-1,8-cineole were identified in plasma and urine of one volunteer. For quantitation of these metabolites and the parent compound, stable isotope dilution assays were developed after synthesis of [(2)H(3)]-1,8-cineole, [9/10-(2)H(3)]-2-hydroxy-1,8-cineole and [(13)C,(2)H(2)]-9-hydroxy-1,8-cineole as internal standards. Using these standards, we quantified 1,8-cineole by solid phase microextraction GC-MS and the hydroxyl-1,8-cineoles by LC-MS/MS after deconjugation in blood and urine of the volunteer. After consumption of 1.02 mg 1,8-cineole (19 μg/kg bw), the hydroxycineoles along with their parent compound were detectable in the blood plasma of the volunteer under study after liberation from their glucuronides with 2-hydroxycineole being the predominant metabolite at a maximum plasma concentration of 86 nmol/L followed by the 9-hydroxy isomer at a maximum plasma concentration of 33 nmol/L. The parent compound 1,8-cineole showed a low maximum plasma concentration of 19 nmol/L. In urine, 2-hydroxycineole also showed highest contents followed by its 9-isomer. Summing up the urinary excretion over 10 h, 2-hydroxycineole, the 9-isomer, the 3-isomer and the 7-isomer accounted for 20.9, 17.2, 10.6 and 3.8% of the cineole dose, respectively.
DNA methylation patterns are tissue specific and may influence tissue-specific gene regulation. Human studies investigating DNA methylation in relation to environmental factors primarily use blood-derived DNA as a surrogate for DNA from target tissues. It is therefore important to know if DNA methylation changes in blood in response to environmental changes reflect those in target tissues. Folate intake can influence DNA methylation, via altered methyl donor supply. Previously, manipulations of maternal folate intake during pregnancy altered the patterns of DNA methylation in offspring but, to our knowledge, the consequences for maternal DNA methylation are unknown. Given the increased requirement for folate during pregnancy, mothers may be susceptible to aberrant DNA methylation due to folate depletion.
Female mice were fed folate-adequate (2 mg folic acid/kg diet) or folate-deplete (0.4 mg folic acid/kg diet) diets prior to mating and during pregnancy and lactation. Following weaning, dams were killed and DNA methylation was assessed by pyrosequencing® in blood, liver, and kidney at the Esr1, Igf2 differentially methylated region (DMR)1, Igf2 DMR2, Slc39a4CGI1, and Slc39a4CGI2 loci. We observed tissue-specific differences in methylation at all loci. Folate depletion reduced Igf2 DMR1 and Slc39a4CGI1 methylation across all tissues and altered Igf2 DMR2 methylation in a tissue-specific manner (p<0.05).
Blood-derived DNA methylation measurements may not always reflect methylation within other tissues. Further measurements of blood-derived and tissue-specific methylation patterns are warranted to understand the complexity of tissue-specific responses to altered nutritional exposure.
With the aim to expand the Italian total antioxidant capacity (TAC) database, the TAC values of 11 spices, 5 dried fruits, 7 sweets, 18 cereal products, 5 pulses, and 6 nuts were determined using three different assays and considering the contribution of bound antioxidant compounds in fiber-rich foods (i. e. cereals, legumes, and nuts). Among spices, saffron displayed the highest antioxidant capacity, whereas among dried fruits, prune exhibited the highest value. The TAC values of all the chocolates analyzed were far higher than the other sweet extracts measured. Among cereal products, whole meal buckwheat and wheat bran had the greatest TAC. Among pulses and nuts, broad bean, lentil and walnuts had the highest antioxidant capacity, whereas chickpeas, pine nuts and peanuts were less effective. The contribution of bound phytochemicals to the overall TAC was relevant in cereals as well as in nuts and pulses. The complete TAC database could be utilized to properly investigate the role of dietary antioxidants in disease prevention.
Thermal processing of food results in the formation of various novel compounds, among others advanced glycation endproducts (AGEs). AGEs result from nonenzymatic glycation reactions between reducing sugars and free amino groups of proteins, peptides, or amino acids. Due to their potential noxious effects, alimentary AGEs are also called glycotoxins. This review provides a summary of the available evidence on the health effects of exaggerated intake of thermally treated food. Data from experimental studies in rodents and from clinical studies in healthy volunteers and in patients suffering from selected diseases in which AGEs are of pathogenetic importance (diabetes, chronic renal failure) are summarized. It is concluded that, an exaggerated intake of thermally processed foods may exert in vivo diabetogenic and nephrotoxic effects, induce low‐grade inflammation, enhance oxidative stress, and promote atherosclerosis.
Contra arguments: http://dx.doi.org/10.1002/mnfr.200600304
The dietary fatty acid cis9,trans11 conjugated linoleic acid (cis9,trans11 CLA) has been shown to modify the function of endothelial cells, monocytes, and platelets, all of which are involved in the development of atherosclerosis. Potential mechanisms for the platelet effects have not been assessed previously. In this study, we assessed how supplementation of the diet with an 80:20 cis9,trans11 CLA blend affects the platelet proteome.
In a double-blind, randomized, placebo-controlled, parallel-group trial, 40 overweight but apparently healthy adults received either 4 g per day of cis9,trans11 CLA-enriched oil or placebo oil, consisting of palm oil and soybean oil, for 3 months. Total platelet proteins were extracted from washed platelets, separated using two-dimensional gel electrophoresis and differentially regulated protein spots were identified by LC-ESI-MS/MS. Supplementation with the CLA blend, compared with placebo, resulted in significant alterations in levels of 46 spots (p < 0.05), of which 40 were identified. Network analysis revealed that the majority of these proteins participate in regulation of the cytoskeleton and platelet structure, as well as receptor action, signaling, and focal adhesion.
The platelet proteomics approach revealed novel insights into regulation of cellular biomarkers of atherogenic and thrombotic pathways by an 80:20 cis9,trans11 CLA blend.
The 9cis,11trans-conjugated linoleic acid (9c,11t-CLA) is reported to have anti-atherogenic properties in animal models and to modulate protein expression in unstimulated human platelets in vivo. Platelet function was therefore investigated after dietary supplementation with 9c,11t-CLA enriched oil (CLA80:20) in a randomized, baseline-controlled cross-over trial.
Forty-three healthy adults at low to moderate risk of cardiovascular disease received 4 g/d of CLA80:20 or placebo for two weeks each. Platelet function, inflammation and endothelial activation were assessed before and after each phase. Compared with placebo, supplementation had no significant effects on platelet function measured by Platelet Function Analyzer-100. Inhibitory effects on collagen-induced aggregation were sex-dependent (P = 0.005) which reached significance only in women (P = 0.045). Thrombin receptor-activating peptide (TRAP)-induced P-selectin expression was higher after supplementation in all subjects (P = 0.017). TRAP-induced platelet fibrinogen binding was also dependent on sex (P = 0.015), with fibrinogen binding after CLA80:20 being higher in males (P = 0.035). Plasma monocyte chemoattractant protein-1 was higher (P = 0.041) after CLA80:20.
No clear evidence was found for inhibition or activation of platelet function as well as inflammation by CLA80:20 in a low to moderate cardiovascular risk group. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
One major health problem in westernized countries is dysregulated fatty acid and cholesterol metabolism that causes pathologies such as metabolic syndrome. Previous studies from our group have shown that proanthocyanidins, which are the most abundant polyphenols in the human diet, regulate lipid metabolism and are potent hypolipidemic agents. The noncoding RNAs, miR-33 and miR-122, regulate genes that are involved in lipid metabolism.
Here, we show that grape seed proanthocyanidins rapidly and transiently repressed the expression of miR-33 and miR-122 in rat hepatocytes in vivo and in vitro. Furthermore, the miR-33 target gene ATP-binding cassette A1 and the miR-122 target gene fatty acid synthase were also modulated by proanthocyanidins. Specifically, ATP-binding cassette A1 mRNA and protein levels were increased, and fatty acid synthase mRNA and protein levels were reduced after the miRNA levels were altered.
These results suggest that proanthocyanidin treatment increased hepatic cholesterol efflux to produce new HDL particles by repressing miR-33, and it reduced lipogenesis by repressing miR-122. These results highlight a new mechanism by which grape seed proanthocyanidins produce hypolipidemia through their effects on miRNA modulators of lipid metabolism.
Tea has been shown to possess several health beneficial properties primarily due to its polyphenolic content. The major polyphenolic compounds in black tea leaves are theaflavins (TFs) formed by oxidative coupling of catechins in tea leaves during its processing. In this paper, we report the characterization of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear inflammatory model and the inhibitory effects of major black tea TFs derivatives on this inflammation. In addition, the effect on inflammatory biomarkers, such as proinflammatory cytokines and arachidonic acid metabolites, are reported as well. A single topical application of TPA to ears of CD-1 mice induced a time- and dose-dependent increase in edema as well as formation of proinflammatory cytokine proteins interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) in mouse ears. A single topical application of equimolar of black tea constituents (TF, theaflavin-3-gallate, theaflavin-3'-gallate, and theaflavin-3,3'-digallate) strongly inhibited TPA-induced edema of mouse ears. Application of TFs mixture to mouse ears 20 min prior to each TPA application once a day for 4 days inhibited TPA-induced persistent inflammation, as well as TPA-induced increase in IL-1beta and IL-6 protein levels. TFs also inhibited arachidonic acid (AA) metabolism via both cyclooxygenase (COX) and lipoxygenase pathways. This observation was substantiated by decreased amounts of AA metabolites prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels. Combined application of TF and sulindac, a nonsteroidal anti-inflammatory drug resulted a significant synergetic anti-inflammatory effect. Oral administration of TFs or the hot water extract of black tea leaves also significantly inhibited TPA-induced edema in mouse ears. In conclusion, proinflammatory cytokines, IL-1beta and IL-6, as well as the intermediated metabolites of AA, PGE2, and LTB4 are good biomarkers for inflammation. Black tea constituents, TF and its derivatives, had strongly anti-inflammatory activity in vivo which may be due to their ability to inhibit AA metabolism via lipoxygenase and COX pathways.
Matrix metalloproteinase (MMP) plays an important role in the invasion and metastasis of cancer cells. The inhibitory effects of bergamottin, a cytochrome P450 inhibitor from Citrus paradis (grapefruit), on tumor invasion and migration and the possible mechanisms involved in this inhibition were investigated in human fibrosarcoma HT-1080 cells. Bergamottin reduced phorbol-12-myristate-13-acetate (PMA)-induced activation of MMP-9 and MMP-2 and further inhibited cell invasion and migration. Bergamottin suppressed PMA-enhanced expression of MMP-9 protein, mRNA and transcription activity levels through suppression of nuclear factor-kappaB (NF-kappaB) activation without changing the tissue inhibitor of metalloproteinase 1 level. Bergamottin also reduced PMA-enhanced MMP-2 expression through suppression of membrane-type 1 MMP, but did not alter tissue inhibitor of metalloproteinase 2 levels. Bergamottin inhibited PMA-induced NF-kappaB nuclear translocation and IkappaBalpha degradation, which are upstream of PMA-induced MMP-9 expression and invasion. Furthermore, bergamottin strongly repressed the PMA-induced phosphorylation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase (JNK), which are dependent on the protein kinase C-delta pathway. In conclusion, we demonstrated that the anti-invasive effects of bergamottin might occur through inhibition of protein kinase C-delta, p38 mitogen-activated protein kinase, and JNK phosphorylation and reduction of NF-kappaB activation, leading to downregulation of MMP-9 expression. These results suggest that the suppression of MMP expression contributes, at least in part, to the antitumor activity of bergamottin.
We previously reported that 6-shogaol strongly suppressed lipopolysaccharide-induced overexpression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in murine macrophages. In this study, we further compared curcumin, 6-gingerol, and 6-shogaol's molecular mechanism of action and their anti-tumor properties. We demonstrate that topical application of 6-shogaol more effectively inhibited 12-O-tetradecanoylphorbol 13-acetate (TPA)-stimulated transcription of iNOS and COX-2 mRNA expression in mouse skin than curcumin and 6-gingerol. Pretreatment with 6-shogaol has resulted in the reduction of TPA-induced nuclear translocation of the nuclear factor-kappaB subunits. 6-Shogaol also reduced TPA-induced phosphorylation of IkappaBalpha and p65, and caused subsequent degradation of IkappaBalpha. Moreover, 6-shogaol markedly suppressed TPA-induced activation of extracellular signal-regulate kinase1/2, p38 mitogen-activated protein kinase, JNK1/2, and phosphatidylinositol 3-kinase/Akt, which are upstream of nuclear factor-kappaB and AP-1. Furthermore, 6-shogaol significantly inhibited 7,12-dimethylbenz[a]anthracene/TPA-induced skin tumor formation measured by the tumor multiplicity of papillomas at 20 wk. Presented data reveal for the first time that 6-shogaol is an effective anti-tumor agent that functions by down-regulating inflammatory iNOS and COX-2 gene expression in mouse skin. It is suggested that 6-shogaol is a novel functional agent capable of preventing inflammation-associated tumorigenesis.
Resveratrol, a phytoalexin present in grapes, has been reported to inhibit multistage mouse skin carcinogenesis. Recent studies showed that topically applied resveratrol significantly inhibited cyclooxygenase-2 (COX-2) expression and activation of nuclear factor-kappaB (NF-kappaB) induced by tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) in mouse epidermis. The aim of the present study was to further explore the effect of resveratrol on TPA-induced signaling pathways in mouse epidermis and to compare with its dimethylether, pterostilbene. Resveratrol and pterostilbene significantly reduced activator protein 1 (AP-1) and NF-kappaB activation. In the case of AP-1, the binding of c-Jun subunit was particularly affected, while only slight effect on c-Fos binding to TPA-responsive element (AP-1 binding consensus sequence) (TRE) site was observed. Both stilbenes inhibited the activation of NF-kappaB by blocking the translocation of p65 to the nucleus and increasing the retention of IkappaBa in the cytosol. The latter might be related to decreased activity of IkappaB kinase and/or proteasome 20S. Reduced activation of transcription factors decreased the expression and activity of COX-2 and inducible nitric oxide synthase (iNOS). In most assays, pterostilbene was either equally or significantly more potent than resveratrol. Pterostilbene might show higher biological activity due to its possible better bioavailability, since substitution of hydroxy with methoxy group increases lipophilicity.
Cell cycle regulation is a critical issue in cancer treatment. Previously, gallic acid (GA) has been reported to possess anticancer ability. Here, we have evaluated the molecular mechanism of GA on cell cycle modulation in a human bladder transitional carcinoma cell line (TSGH-8301 cell).
Using flow cytometer analysis, exposure of the cells to 40 μM GA resulted in a statistically significant increase in G2/M phase cells, which was accompanied by a decrease in G0/G1 phase cells. GA-treated cells resulted in significant growth inhibition in a dose-dependent manner accompanied by a decrease in cyclin-dependent kinases (Cdk1), Cyclin B1, and Cdc25C, but significant increases in p-cdc2 (Tyr-15) and Cip1/p21 by western blotting. Additional mechanistic studies showed that GA induces phosphorylation of Cdc25C at Ser-216. This mechanism leads to its translocation from the nucleus to the cytoplasm resulting in an increased binding with 14-3-3β. When treated with GA, phosphorylated Cdc25C can be activated by ataxia telangiectasia-mutated checkpoint kinase 2 (Chk2). This might be a DNA damage response as indicated by Ser-139 phosphorylation of histine H2A.X. Furthermore, treatment of the cells with a Chk2 inhibitor significantly attenuated GA-induced G2/M phase arrest.
These results indicate that GA can induce cell cycle arrest at G2/M phase via Chk2-mediated phosphorylation of Cdc25C in a bladder transitional carcinoma cell line.
IL-6 is well recognized to be a potent bone resorptive agent and thus in the development of periodontal disease. Epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), the major catechins in green tea, and theaflavin-3,3'-digallate (TFDG), polyphenol in black tea, have multiple beneficial effects, but the effects of catechins and theaflavins on IL-6 production in human gingival fibroblasts (HGFs) are not known. In this study, we investigated the mechanisms by which EGCG, ECG, and TFDG inhibit tumor necrosis factor superfamily 14 (TNFSF14)-induced IL-6 production in HGFs. We detected TNFSF14 mRNA expression in human diseased periodontal tissues. TNFSF14 increased IL-6 production in HGFs in a concentration-dependent manner. EGCG, ECG, and TFDG prevented TNFSF14-mediated IL-6 production in HGFs. EGCG, ECG, and TFDG prevented TNFSF14-induced extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and nuclear factor-kappaB activation in HGFs. Inhibitors of ERK, JNK, and nuclear factor-kappaB decreased TNFSF14-induced IL-6 production. In addition, EGCG, ECG, and TFDG attenuated TNFSF14 receptor expression on HGFs. These data provide a novel mechanism through which the green tea and black tea polyphenols could be used to provide direct benefits in periodontal disease.
Studies on the effect of the artichoke extract (AE) on oxidation of palmitic-1-14C acid administered intravenously to rats at a dose 25 and 50 mg/kg bw demonstrated marked enhancement of both 14CO2 expiration rate and 14CO2 recovery in the expired air. The extract suppressed accumulation of palmitic-1-14C acid in serum lipids and epididymal fat pad tissue as well. The effects of the extract on 14CO2 expiration rate, 14CO2 recovery, as well as accumulation of palmitic-1-14C acid were dose dependent. Total14CO2 recovery in expired air during 60 min was elevated by 17.3% (p < 0.05) and 52.1% (p < 0.001) in rats administered the extract at a dose of 25 and 50 mg/kg, respectively. The rats supplemented with the AE at a dose of 25 and 50 mg/kg bw were characterized by 10.0% (not significant) and 19% (p < 0.05) decrease in( 14)C radioactivity of serum lipids as well as reduction of epididymal fat tissue 14C radioactivity by 8.7 and 17.5% (p < 0.05), respectively, in comparison with the control rats. Thus, the results demonstrate that the AE possess stimulatory properties with respect to oxidation of palmitic acid administered to rats, and provide new information on the mechanism of antilipemic activity of the extract associated with activation of lipid oxidation in the organism.
Acrylamide (AA) is formed during heating of carbohydrate rich foods in the course of the Maillard reaction. AA has been classified as probably carcinogenic to humans. Storage experiments with roasted coffee have shown that AA levels decrease depending on storage time and temperature. In the present study the fate of AA lost during storage of roasted and ground (R&G) coffee was studied, using 14C-labeled AA as radiotracer. Radiolabel was measured in coffee brew, filter residue, and volatiles. In the brew, total (14)C-label decreased during storage of R&G coffee, while activity in the filter residue built up concomitantly. [2,3-14C]-AA (14C-AA) was the only 14C-related water extractable low molecular compound in the brew detected by radio-HPLC. No formation of volatile 14C-AA-related compounds was detected during storage and coffee brewing. Close to 90% of the radiolabel in the filter residue (spent R&G coffee, spent grounds) remained firmly bound to the matrix, largely resisting extraction by aqueous ammonia, ethyl acetate, chloroform, hexane, and sequential polyenzymatic digest. Furanthiols, which are abundant as aroma components in roasted coffee, have not been found to be involved in the formation of covalent AA adducts and thus do not contribute substantially to the decrease of AA during storage.
In humans, varying amounts of absorbed β-carotene are oxidatively cleaved by the enzyme β,β-carotene 15,15'-monooxygenase 1 (BCMO1) into two molecules of all-trans-retinal. The other carotenoid cleavage enzyme β,β-carotene 9',10'-dioxygenase (BCDO2) cleaves β-carotene at the 9',10' double bond forming β-apo-10'-carotenal and β-ionone. Although the contribution of BCDO2 to vitamin A formation has long been debated, BCMO1 is currently considered the key enzyme for retinoid metabolism. Furthermore, BCMO1 has limited enzyme activity towards carotenoids other than provitamin A carotenoids, whereas BCDO2 exhibits a broader specificity. Both enzymes are located at different sites within the cell, with BCMO1 being a cytosolic protein and BCDO2 being located in the mitochondria. Expression of BCMO1 in tissues other than the intestine has recently revealed its function for tissue-specific retinoid metabolism with importance in embryogenesis and lipid metabolism. On the other hand, biological activity of BCDO2 metabolites has been shown to be important in protecting against carotenoid-induced mitochondrial dysfunction. Single-nucleotide polymorphisms (SNPs) such as R267S and A379V in BCMO1 can partly explain inter-individual variations observed in carotenoid metabolism. Advancing knowledge about the physiological role of these two enzymes will contribute to understanding the importance of carotenoids in health and disease.
Ginger, the rhizome of Zingiber officinale, is a traditional medicine with anti-inflammatory and anticarcinogenic properties. This study examined the growth inhibitory effects of the structurally related compounds 6-gingerol and 6-shogaol on human cancer cells. 6-Shogaol [1-(4-hydroxy-3-methoxyphenyl)-4-decen-3-one] inhibits the growth of human cancer cells and induces apoptosis in COLO 205 cells through modulation of mitochondrial functions regulated by reactive oxygen species (ROS). ROS generation occurs in the early stages of 6-shogaol-induced apoptosis, preceding cytochrome c release, caspase activation, and DNA fragmentation. Up-regulation of Bax, Fas, and FasL, as well as down-regulation of Bcl-2 and Bcl-X(L )were observed in 6-shogaol-treated COLO 205 cells. N-acetylcysteine (NAC), but not by other antioxidants, suppress 6-shogaol-induced apoptosis. The growth arrest and DNA damage (GADD)-inducible transcription factor 153 (GADD153) mRNA and protein is markedly induced in a time- and concentration-dependent manner in response to 6-shogaol.
The effectiveness of low gamma-irradiation doses in the destruction of Escherichia coli O 157 : H7 and Listeria monocytogenes in raw beef sausages was investigated. Raw samples of fresh manufactured beef sausage were subjected to gamma-irradiation at doses of 0, 1, 2, and 3 kGy. Then samples were cold-stored (4 +/- 1 degrees C) for 12 days and the effects of irradiation and storage on the counts of these harmful bacteria were studied. Moreover, the effects of irradiation and storage on the percentages of free fatty acids (FFAs) in lipids, on the p-anisidine values of lipids, solubility of sarcoplasmic and myofibrilar proteins, and water-holding capacity (WHC) were also determined. The results showed that gamma-irradiation at 1 and 2 kGy significantly reduced the counts of E. coli O 157 : H7 and L. monocytogenes, while 3 kGy dose effectively eliminated these bacteria by more than 4 log and 3 log units, respectively, and could keep their counts below the detection level during storage. Gamma-irradiation had no significant effects on the percentages of FFAs in lipids, solubility of sarcoplasmic and myofibrilar proteins, and WHC of samples, while it significantly increased the p-anisidine value of lipids. During storage, significant increases in the percentages of FFAs and p-anisidine values were observed for lipids of irradiated and nonirradiated sausages, while the solubility of sarcoplasmic and myofibrilar proteins showed no significant changes. Moreover, samples of irradiated and nonirradiated sausages showed significant decreases in their WHC during the first 6 days of storage at 4 +/- 1 degrees C, then showed no significant changes. Finally, gamma-irradiation at a dose of 3 kGy appeared to be sufficient to improve the microbiological safety of raw beef sausages without adverse effects on their chemical properties.
Selenium is an essential micronutrient. In the present study, trace amount of selenite (0.01 μM) was evaluated for oxidative stress resistance and potential associated factors in Caenorhabditis elegans.
Selenite-treated C. elegans showed an increased survival under oxidative stress and thermal stress compared to untreated controls. Further studies demonstrated that the significant stress resistance of selenite on C. elegans could be attributed to its in vivo free radical-scavenging ability. We also found that the oxidative and thermal stress resistance phenotypes by selenite were absent from the forkhead transcription factor daf-16 mutant worms. Moreover, selenite influenced the subcellular distribution of DAF-16 in C. elegans. Furthermore, selenite increased mRNA levels of stress-resistance-related proteins, including superoxide dismutase-3 and heat shock protein-16.2. Additionally, selenite (0.01 μM) upregulated expressions of transgenic C. elegans carrying sod-3::green fluorescent protein (GFP) and hsp-16.2::GFP, whereas this effect was abolished by feeding daf-16 RNA interference in C. elegans. Finally, unlike the wild-type N2 worms, the oxidative stress resistance phenotypes by selenite were both absent from the C. elegans selenoprotein trxr-1 mutant worms and trxr-1 mutants feeding with daf-16 RNA interference.
These findings suggest that the antioxidant effects of selenite in C. elegans are mediated via DAF-16 and TRXR-1.
Xanthohumol (XN) is one of the major prenylflavonoids found in hop cones (Humulus lupulus L.). In this study, we investigated the cell growth inhibitory potential of XN on cultured human colon cancer cells. Cell proliferation was measured by sulforhodamine B staining. Poly(ADP-ribose)polymerase (PARP) cleavage, activation of caspases-3, -7, -8, and -9, and Bcl-2 family protein expression were detected by Western blot analyses. XN significantly reduced proliferation of the HCT 116-derived colon cancer cell line 40--16. Half-maximal inhibitory concentrations decreased from 4.1 microM after 24 h treatment to 3.6 and 2.6 microM after 48 and 72 h incubation, respectively. Treatment with 15 microM XN for 48 h and with 5 microM for 72 h led to the detection of the cleaved 89 kDa fragment of 116 kDa PARP as an indication of apoptosis induction. Concomitantly, we observed activation and cleavage of the effector caspases-3 and -7, induced by activation of the initiator caspases -8 and -9. Expression of anti-apoptotic Bcl-2 was down regulated when the cells were treated with XN for 48--72 h. We conclude that induction of apoptosis by downregulation of Bcl-2 and activation of the caspase cascade may contribute to the chemopreventive or therapeutic potential of XN.
Phytochemicals have been proposed to offer protection against a variety of chronic ailments including cardiovascular diseases, obesity, diabetes, and cancer. As for cancer protection, it has been estimated that diets rich in phytochemicals can significantly reduce cancer risk by as much as 20%. Phytosterols are specific phytochemicals that resemble cholesterol in structure but are found exclusively in plants. Phytosterols are absorbed from the diet in small but significant amounts. Epidemiological data suggest that the phytosterol content of the diet is associated with a reduction in common cancers including cancers of the colon, breast, and prostate. The means by which dietary phytosterols may be achieving these effects is becoming clearer from molecular studies with tumorigenic research models. Phytosterols affect host systems potentially enabling more robust antitumor responses, including the boosting of immune recognition of cancer, influencing hormonal dependent growth of endocrine tumors, and altering sterol biosynthesis. In addition, phytosterols have effects that directly inhibit tumor growth, including the slowing of cell cycle progression, the induction of apoptosis, and the inhibition of tumor metastasis. This review summarizes the current state of knowledge regarding the anticancer effects of phytosterols.