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Anti-tumor potential and acute toxicity of Jacaranda puberula Cham. (Bignoniacea)
Abstract
Cancer chemotherapy is an important strategy to treat this leading cause of death worldwide and plants may constitute a source of new antineoplastic agents. This work fractionated the ethanolic extract of Jacaranda puberula leaves and studied the in vitro antitumoral action and some toxicological effects of the most bioactive fraction. Cell lines related to worldwide cancers were used. The Dichloromethane (DCM) and PP fractions were the most bioactive ones. The anti-tumoral action of the DCM fraction was higher than that of the crude EtOH extract while that of PP fraction was higher than the original one (DCM) for both breast (MCF-7), prostate (PC3) and lung (A549) tumor cells, chronic leukemia cells. The K562 cells were the most sensitive cell line. The PP fraction (20 μg/mL) cytotoxicity for these cells was similar to that of the ursolic acid triterpene or the antineoplastic ethoposide. The PP fraction inhibited K562 cell proliferation without cell cycle arrest in a specific phase or apoptosis. PP increased the mitochondrial reduction activity of lymphocytes. After a single dose by oral route, PP fraction did not induce intrinsic acute toxicity or animal death. This work demonstrated that the J. puberula fraction (PP) present high in vitro anti-tumoral effect with no cytotoxicity for immune system cells or oral acute toxicity, improving the Jacaranda puberula ethnopharmacology and reporting new biological effects for the genus Jacaranda.
... Natural products such as polyphenols, alkaloids and terpenes are important sources of compounds able to treat several diseases due to their diverse pharmacological properties, including cytotoxic and cancer chemo preventives effects (De Almeida et al., 2013). The vast diversity of the Brazilian flora stimulates the exploration of plant extracts with medical and biological activities (Rennó et al., 2008) including with anticancer properties. ...
... A highly important chemical class is the triterpenes, mainly because of their medicinal properties. Different kinds of triterpenes are correlated to anti-cancer activities, such as the pentacyclic skeletons (de Almeida et al., 2013;Hao et al., 2013). Moreover, the research for new anti-cancer drugs shows that natural pentacyclic triterpenes rarely exhibit severe side effects (Lemos et al., 2012). ...
... In addition to the oleanane type triterpenes, other classes have already been isolated from Passiflora species, such as the cicloartanes triterpenes (passiflorine and ciclopassifloside) (Arechabala et al., 1999). The maslinic acid is an important compound recognized to induce apoptosis and, for blocking the growth of the Ehrlich HeLa carcinoma (de Almeida et al., 2013;Rusiecka et al., 2016). Concerning the phytosterols stigmasterol and β-sitosterol, identified in P. mucronata on the present study, we highlight that, unexpectedly, this is the first report describing their presence in the Passiflora genus. ...
Cancer is one of the most prevalent diseases worldwide and the natural products could be a source of bioactive compounds. Passiflora mucronata (PM) belongs to a very known vegetal genus, although, there are no studies about cytotoxic activity or isolated compounds. Different extracts from PM were obtained by liquid-liquid partition (P), Soxhlet (Sox) and supercritical fluid (SFE1-5) extraction techniques, being compared concerning their yields, chemical profile and cytotoxicity. The Sox extracts showed the highest yields (6.03%: hexane; 2.51%: dichloromethane) followed by SFE (from 4.34 to 1.63%) and partitions (1.06 and 2.26%). The hexane partition (HP) showed the best cytotoxic activity against K562 cell line (IC50 = 18.72 µg.mL-1). From HP, the following compounds were identified and analysed its cytotoxic activities: β-amyrin (IC50 = 3.92 µg.mL-1), β-sitosterol (IC50 = 3.37 µg.mL-1), stigmasterol (IC50 = 3.31 µg.mL-1) and oleanolic acid. Stigmasterol induced about 75% of K562 total apoptosis. The compounds were tested against MA-104 cell line and the selective index (SI) attributed (SI >10 for all compounds). This indicates good selectivity to K562 cell line at the expense of MA-104. This is the first time, identifying those compounds to PM .
... From these results, it can be concluded that the cytotoxicity of grape pomace extract increases with concentration. This result has been previously reported with plant extracts with high content of phenolic compounds [41,42]. The same analysis was done with combinations of grape pomace extract with ciprofloxacin, chloramphenicol and ampicillin, using the minimum concentration of extract (47 μg/mL) in which a synergistic effect was observed. ...
Synergy could be an effective strategy to potentiate and recover antibiotics nowadays useless in clinical treatments against multi-resistant bacteria. In this study, synergic interactions between antibiotics and grape pomace extract that contains high concentration of phenolic compounds were evaluated by the checkerboard method in clinical isolates of Staphylococcus aureus and Escherichia coli. To define which component of the extract is responsible for the synergic effect, phenolic compounds were identified by RP-HPLC and their relative abundance was determined. Combinations of extract with pure compounds identified there in were also evaluated. Results showed that the grape pomace extract combined with representatives of different classes of antibiotics as β-lactam, quinolone, fluoroquinolone, tetracycline and amphenicol act in synergy in all S. aureus and E. coli strains tested with FICI values varying from 0.031 to 0.155. The minimal inhibitory concentration (MIC) was reduced 4 to 75 times. The most abundant phenolic compounds identified in the extract were quercetin, gallic acid, protocatechuic acid and luteolin with relative abundance of 26.3, 24.4, 16.7 and 11.4%, respectively. All combinations of the extract with the components also showed synergy with FICI values varying from 0.031 to 0.5 and MIC reductions of 4 to 125 times with both bacteria strains. The relative abundance of phenolic compounds has no correlation with the obtained synergic effect, suggesting that the mechanism by which the synergic effect occurs is by a multi-objective action. It was also shown that combinations of grape pomace extract with antibiotics are not toxic for the HeLa cell line at concentrations in which the synergistic effect was observed (47 μg/mL of extract and 0.6–375 μg/mL antibiotics). Therefore, these combinations are good candidates for testing in animal models in order to enhance the effect of antibiotics of different classes and thus restore the currently unused clinical antibiotics due to the phenomenon of resistance. Moreover, the use of grape pomace is a good and low-cost alternative for this purpose being a waste residue of the wine industry.
... The present study showed a reduction in the mitochondrial membrane potential and an increase in caspase-3 activation, with a decrease in cell viability and an increase in cell death through late apoptosis at the highest concentrations of E-Jds evaluated. The cytotoxic action observed in this study corroborates that observed by De-Almeida et al., [48] for the hydroethanolic extract of Jacaranda puberula Cham in K562 erythroleukemia cells, although the mechanism of death indicated in that study was apoptosis. E-Jds also induced death through necrosis, an alternative mode of death for cells resistant to apoptosis that occurs with some conventional chemotherapeutic agents [49]. ...
Background and Purpose
Leaves of Jacaranda decurrens are used in traditional Brazilian medicine to treat metabolic diseases related to increased reactive oxygen species. The present study evaluated the antioxidant and cytotoxic potential of hydroethanolic extract from the leaves of Jacaranda decurrens subsp. symmetrifoliolata.
Experimental Approach
Phenolic compounds, flavonoids and saponins were evaluated in an ethanol∶water (80∶20, v/v) extract from the leaves of Jacaranda decurrens subsp. symmetrifoliolata (E-Jds). The antioxidant activity of E-Jds was investigated by assessing the following: 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity; protection against 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced hemolysis of erythrocytes; in vitro and in vivo malondialdehyde dosage; and the ability to activate antioxidant enzymes. K562 leukemia cells were used for the cytotoxic evaluation of E-Jds and for the assessment of the cell death profile through flow cytometry.
Key Results
Phenolic and flavonoid compounds were quantified as 14.38% and 2.15%, respectively, of E-Jds. These phenolic and flavonoid compounds proved to be able to scavenge DPPH free radicals with an IC50 of 9.3±3.3 µg/mL, to protect up to 50% of erythrocytes against AAPH-induced hemolysis and to reduce in vitro and in vivo malondialdehyde levels up to 84% and 22%, respectively. E-Jds also increased glutathione peroxidase enzyme activity, with a concomitant decrease in superoxide dismutase and catalase activity, and exhibited dose-dependent cytotoxic activity on K562 erythroleukemia cells with cell death occurring via both late apoptosis and necrosis.
Conclusions
E-Jds exhibits in vitro and in vivo antioxidant potential, which may be the mechanism mediating the metabolic activities reported in folk medicine. Furthermore, the cytotoxic activity identified in this study contributes with the knowledge of antiproliferative activities that have been described in the literature for the genus Jacaranda.
... This finding corroborates the concern on the Livro Vermelho da Flora do Brasil about J. macrantha and J. puberula, flagged as species "with a verified and projected decline". It is worth mentioning that the chemical and biological activities of Jacaranda puberula have been studied (Passero et al., 2007;Martins et al., 2008, De-Almeida et al., 2013. Martinelli and Moraes (2013) point that, among the species considered as endangered on the Livro Vermelho da Flora do Brasil, only 5,2% (244) of them have particular information about their use shown on the literature and that their most common use is related to their ornamental value, followed by the bioactive properties and timber value. ...
Medicinal plants have been used for many years and are the source of new active substances and new drugs of pharmaceutical interest. The popular knowledge contained in the open- air markets is studied through urban ethnobotany, and is a good source of information for ethnobotanical research. In this context, we surveyed the literature on works concerning open-air markets in the State of Rio de Janeiro to gather knowledge of the commercialized plants therein. A literature search resulted in ten studies with 376 listed species, distributed in 94 families and 273 genera. Asteraceae family had the greater representation, followed by Lamiaceae and Fabaceae. Solanum was the most frequent genus. Two hundred and twenty four species could be considered potentially toxic or potentially interact with other drugs/medicines. Eighteen species are referred as “not for use during pregnancy”, and 3 “not for use while nursing”. These results are a source of concern since in Brazil, as it is worldwide, there is the notion that plants can never be harmful. The results for the Sørensen Coefficient showed greater similarity between works performed in very close study areas. Other studies presented low similarity, mainly because of the difficulty in plant identification or a very specific focus in methodology.
This study aimed to evaluate the medicinal potential of tree species in Araucaria Forest (FOM) remnants in Santa Catarina Plateau, highlighting those with therapeutic actions attested in scientific trials, as well as those with medicinal potential according to ethnobotanical records. The floristic composition was sampled through the point-centered quarter method, registering the individuals with DBH ≥ 5 cm closest to the center point. Sampling was conducted in Permanent Preservation Areas (APP’s) and/or Legal Reserve, with the help of 20 transects with 20 points quadrants each, totaling 2.61 hectares. Among the species recorded and identified, 16 of them, classified into 13 plant families, have medicinal potential described and attested in literature and 12 species within 10 families, are suggested as potential, according to ethnobotanical concepts. The present study showed that these sites may contribute to the maintenance of species of FOM and to base future studies on medicinal plants and/or other bioactive potential.
In the search for possible new anti-cancer agents, we investigated the effects of 75 aqueous and methanol extracts from 41 Argentinean plant species. The effect in cell growth was evaluated in the LM2 mammary adenocarcinoma cells. In a second stage, the highly active selected extracts were assayed in 3 other tumour cell lines: melanoma B16, bladder MB49 and lung A549; and 3 normal cell lines: mammary Hb4a and keratinocytes PAM212 and HaCat. Eight methanol extracts were found to be highly cytotoxic: Collaea argentina leaf, Iochroma australe leaf, Ipomoea bonariensis flower, Jacaranda mimosifolia flower, Solanum amygdalifolium flower, Solanum chacoense leaf, Solanum sisymbriifolium flower and Solanum verbascifolium flower. However, extract inhibition on cell growth was highly dependent on cell type. In general, except for the highly resistant cell lines, the inhibitory concentrations 50% were in the range of 10-150 μg/ml The eight extracts highly inhibited cell growth in a concentration-dependent manner, and in general the methanol extracts were always more active than the aqueous. Murine cells appear to be more sensitive than human cells to the cytotoxic action of the plant extracts. The human melanoma B16 line was the most resistant to four of the extracts. In terms of selectivity, S. verbascifolium was the species which showed most selectivity for tumour cells. Overall, this is one of the first studies focusing on southern South American native plants and their biological effects. Since some species of 5 genera analyzed have been reported to possess different degrees of alkaloid content, we examined microtubule structures after extract treatments. The eight extracts induced destabilization, condensation and aggregation of microtubules in LM2 cells, although no depolarization, typical of Vinca alkaloids damage was observed. In a near future, antitumour activity of purified fractions of the extracts administered at non-toxic doses will be assayed in transplantable murine tumour models.
The control of cancer, the second leading cause of death worldwide, may benefit from the potential that resides in alternative therapies. The primary carcinogens stem from a variety of agricultural, industrial, and dietary factors. Conventional therapies cause serious side effects and, at best, merely extend the patient's lifespan by a few years. There is thus the need to utilise alternative concepts or approaches to the prevention of cancer. This review focuses on the many natural products that have been implicated in cancer prevention and that promote human health without recognisable side effects. These molecules originate from vegetables, fruits, plant extracts, and herbs.
Detection of antiproliferative activity and bioactivity-guided fractionation of viscin, a lipophilic extract from Viscum album L., led to the isolation of betulinic acid, oleanolic acid and ursolic acid as active components. Viscin, betulinic acid, oleanolic acid and ursolic acid inhibited growth and induced apoptotic cell death in Molt4, K562 and U937 leukaemia cells. The growth inhibitory effect of viscin was more pronounced in Molt4 and U937 cells (IC50 (concentration that inhibited cell proliferation by 50%): 118 +/- 24 and 138 +/- 24 microg mL(-1)) than in K562 cells (IC50: 252 +/- 37 microg mL(-1)). Oleanolic acid was the least effective in all cell lines (7.5-45.5% inhibition at 10 microg mL(-1)) and ursolic acid the most active in Molt4 and U937 cells (81.8 and 97.8% inhibition, respectively, at 5 microg mL(-1)). A dose-dependent loss of membrane phospholipid asymmetry associated with apoptosis was induced in all cell lines as shown in flow cytometry by the externalization of phosphatidylserine and morphological changes in cell size and granularity. There were differences in individual cell lines' response towards the apoptosis-inducing effect of viscin, betulinic acid, oleanolic acid and ursolic acid. The triterpenoids beta-amyrin, beta-amyrinacetate, lupeol, lupeolacetate, beta-sitosterol and stigmasterol, and the fatty acids oleic acid, linoleic acid, palmitic acid and stearic acid were also present in the lipophilic extract.
Bidens pilosa (L.) (Asteraceae) is a medicinal plant traditionally used in Brazil for treating conditions that can be related to cancer. Therefore the present study was carried out to evaluate the antitumor activity of extracts obtained from the aerial parts of this plant species.
The crude hydroalcoholic extract (HAE) (water:alcohol, 6:4) and solvent fractions (chloroform=CHCl3,ethyl acetate=EtOAc, methanol=MeOH) were assessed for cytotoxicity assay by the brine shrimp and hemolytic, MTT and NRU assays. The antiproliferative potential of the crude extract and fractions was investigated in vivo using the Ehrlich ascites carcinoma (EAC) in isogenic Balb/c mice that were administered intraperitoneally 150 and 300 mg/kg body weight per day for nine days beginning 24 h after tumor inoculation.
In in vitro cytotoxicity using Ehrlich ascites carcinoma cell line assay CHCl3 extract proved to be more toxic than the crude HAE with an IC(50) of 97+/-7.2 and 83+/-5.2 microg/mL to NRU and MTT, respectively. Histomorphological evaluations indicated that the treatment with CHCl3 and HAE extracts significantly reduced (P<0.05) body weight, abdominal circumference, tumor volume, packed cell volume and viable cell count, when compared to EAC control group. Furthermore, nonviable tumor cell count increased significantly (P<0.01) only under treatment with CHCl3 or HAE, and this was accompanied by a marked percentage increase in life span (54.2 and 41.7%, respectively). Biochemical assays revealed that CHCl3 and HAE extracts were also able to decrease serum LDH activity (39.5 and 30.6%) and GSH concentration (94.6 and 50.7%) in ascitic fluid, respectively.
The chloroform fraction showed the best and methanolic the worst antitumor activity.
The antioxidant activity of leaf extracts from Jacaranda puberula Cham., Bignoniaceae, was assayed by the DPPH (2,2-diphenyl-1-picryl-hydrazyl) free radical scavenging method. Three phytomedicines (F1, F2, and F3) used as blood depurative, were tested by the same method. The free radical scavenger potential was measured by the discoloration of the solution. The EC(50) values from Gingko biloba EGb 761(R) extract and rutin, used as antioxidant for medical purposes, were used as reference. The ethanol extract (EE), ethyl acetate (EA), butanol (EB), aqueous (EAq) and the sample A (obtained from extract EB), showed lower EC(50) values than other extracts and phytomedicines. The antioxidant activity (AA) of the extracts was related with the presence of the polyphenol compounds such as verbascoside (1) and cis-caffeoyl aldehyde (2). These structures were determined by chemical and spectroscopic methods and comparison with literature data.
Cancer is a leading global cause of death and disability, responsible for approximately 7.6 million deaths each year. Around one-third of cancers are attributable to a small number of preventable risk factors - including smoking and the harmful consumption of alcohol - for which effective interventions exist at the population level. Despite this, progress in global cancer control has been slow and patchy, largely due to the weak and fragmented nature of both the global and national responses. This has been exacerbated by the economic crisis and the tendency for other challenges involving food, energy security and climate change to overshadow cancer on the global policy agenda. This paper reviews the global burden of cancer, and summarizes knowledge about effective interventions. Responding to the global challenge of cancer requires a comprehensive and integrated approach that includes legislation and regulation. A re-invigorated approach to global cancer prevention, within the broader context of non-communicable disease prevention, is an important pathway to global health and development.
To investigate the proliferation-inhibiting and apoptosis-inducing effects of ursolic acid (UA) and oleanolic acid (OA) on multi-drug resistance (MDR) cancer cells in vitro.
UA and OA in different concentrations (0-100 μmol/L) were added separately to cultures of different cancer cell lines, including the human colon cancer cell lines SW480 and SW620, human acute myelocytic leukemia cancer cell lines HL60 and HL60/ADR, human chronic myelogenous leukemia cell lines K562 and K562/ADR, and the human breast cancer cell lines MCF-7 and MCF-7/ADR. Effects of UA and OA on cell proliferation were detected by 3-(4,5-dimethyl-2-thiazole)-2-5-biphenly-tetrazole bromide (MTT) method and effects on cell apoptosis were tested by flow cytometry (FCM) and Western blot at 24, 48, and 72 h after treatment.
Both UA and OA showed significant inhibition on parent and MDR cell lines in a time- and concentration-dependent manner; the drug-resistant multiple of them on K562 and K562/ADR as well as on HL60 and HL60/ADR was 1; the effects of UA were better than those of OA in inhibiting cell growth of solid colonic cancer and breast cancer. After SW480 cells were treated by UA at the concentrations of 0-40 μmol/L for 48 h, FCM showed that annexin V (AV) positive cells and hypodiploid peak ratio increased along with the increase in the drug's concentrations; and Western blot found that expressions of Bcl-2, Bcl-xL and survivin decreased in a concentration-dependent manner.
Both UA and OA have antitumor effects on cancer cells with MDR, and the optimal effect is shown by UA on colonic cancer cells. Also, UA shows cell apoptosis-inducing effect on SW480, possibly by way of down-regulating the expressions of apoptosis antagonistic proteins, Bcl-2, Bcl-xL, and survivin.
This research aimed to investigate erythrodiol, uvaol, oleanolic acid, and maslinic acid scavenging capacities and their effects on cytotoxicity, cell proliferation, cell cycle, apoptosis, reactive oxygen species (ROS) level, and oxidative DNA damage on human MCF-7 breast cancer cell line. The results showed that erythrodiol, uvaol, and oleanolic acid have a significant cytotoxic effect and inhibit proliferation in a dose- and time-dependent manner. At 100 μM, erythrodiol growth inhibition occurred through apoptosis, with the observation of important ROS production and DNA damage, whereas uvaol and oleanolic acid growth inhibition involved cell cycle arrest. Moreover, although all tested triterpenes did not show free radical scavenging activity using ABTS and DPPH assays, they protected against oxidative DNA damage at the concentration 10 μM. Uvaol and oleanolic and maslinic acids, tested at 10 and 100 μM, also reduced intracellular ROS level and prevented H(2)O(2)-induced oxidative injury. Overall, the results suggest that tested triterpenes may have the potential to provide significant natural defense against human breast cancer.
Plant secondary metabolites and their semi-synthetic derivatives continue to play an important role in anticancer drug therapy. In this short review, selected single chemical entity antineoplastic agents from higher plants that are currently in clinical trials as cancer chemotherapy drug candidates are described. These compounds are representative of a wide structural diversity. In addition, the approaches taken toward the discovery of anticancer agents from tropical plants in the laboratory of the authors are summarized. The successful clinical utilization of cancer chemotherapeutic agents from higher plants has been evident for about half a century, and, when considered with the promising pipeline of new plant-derived compounds now in clinical trials, this augurs well for the continuation of drug discovery research efforts to elucidate additional candidate substances of this type.
Apoptotic effects of oleanolic acid (OA) and ursolic acid (UA) on human liver cancer HepG2, Hep3B, Huh7 and HA22T cell lines were examined. OA or UA at 2, 4, 8 micromol/L were used and their effects on cell viability, DNA fragmentation, mitochondrial membrane potential (MMP), activity of Na(+)-K(+)-ATPase, caspase-3 and caspase-8, cell adhesion, level of intercellular adhesion molecule (ICAM)-1 and vascular endothelial growth factor (VEGF) in these cell lines were determined. OA or UA treatments concentration-dependently decreased cell viability and increased DNA fragmentation in HepG2 and Hep3B cell lines (P<0.05). However, these two compounds reduced viability and increased DNA fragmentation in Huh7 cell only at 4 and 8 micromol/L (P<0.05). OA or UA treatments concentration-dependently lowered MMP in HepG2, Hep3B and HA22T cell lines (P<0.05). These two compounds also concentration-dependently diminished Na(+)-K(+)-ATPase activity and VEGF level in four test cell lines (P<0.05). Besides Huh7 cell, OA or UA treatments concentration-dependently elevated caspase-3 and caspase-8 activities in other three cell lines (P<0.05). Besides HA22T cell, these two compounds concentration-dependently inhibited cell adhesion and decreased ICAM-1 level in other three cell lines (P<0.05). These findings support that OA and UA are potent anti-cancer agents to cause apoptosis in these liver cancer cell lines.
Cancer is a leading cause of death worldwide. Cancer chemoprevention is one of the promising strategies to decrease its incidence and both plant extracts and natural products may constitute sources of new chemoprevention agents. Some Brazilian species popularly used to treat inflammatory conditions were selected for evaluation for cancer chemoprevention. A total of 32 extracts/fractions from Hancornia speciosa, Davilla elliptica, Jacaranda caroba, Mansoa hirsuta, Remija ferrugina, Solanum paniculatum and Xyris pterygoblephara, along with a mixture of ursolic and oleanolic acids obtained from J. caroba and a dihydroisocoumarin isolated from aerial parts of X. pterygoblephara were tested for their cancer chemoprevention activity [inhibition of 12-O-tetradecanoyl-13-acetate (TPA)-mediated NF-kappaB activation, ornithine decarboxylase (ODC) and cyclooxygenase-1 (COX-1); induction of antioxidant response element (ARE)]. Several extracts/fractions were active in more than one assay and those from H. speciosa, M. hirsuta and J. caroba mediated strong responses with NF-kappaB, COX-1 and ARE, respectively.
The genus Jacaranda, an important representative of the tribe Tecomeae in the family Bignoniaceae, is interesting from both biological and chemical perspectives. In this review, a contemporary summary of biological and pharmacological research on Jacaranda species will be presented and critically evaluated. Significant findings in the treatment of protozoa-caused diseases as well as of skin illnesses have been presented in ethnobotanical reports and recent studies were performed on crude extracts for certain Jacaranda species. Jacaranone, the most important constituent isolated is known to possess anti-cancer activity. Recently, high cutaneous toxicity together with moderate activity against leishmaniasis was described. Very few additional data are available on the biological activities and cytotoxicity of pure compounds from Jacaranda. Thirteen of the forty-nine distinguished species of Jacaranda have been reported in scientific literature as ethnobotanically used or phytochemically investigated. However, information about a chemical profile is available only for six species. The following article gives a critical assessment of the literature to date and aims to show that the pharmaceutical potential of this genus has been underestimated and deserves closer attention.
A tetrazolium salt has been used to develop a quantitative colorimetric assay for mammalian cell survival and proliferation. The assay detects living, but not dead cells and the signal generated is dependent on the degree of activation of the cells. This method can therefore be used to measure cytotoxicity, proliferation or activation. The results can be read on a multiwell scanning spectrophotometer (ELISA reader) and show a high degree of precision. No washing steps are used in the assay. The main advantages of the colorimetric assay are its rapidity and precision, and the lack of any radioisotope. We have used the assay to measure proliferative lymphokines, mitogen stimulations and complement-mediated lysis.
A 250-cGy whole-body γ-radiation dose was used to induce thymus regression in mice, and to study the expression and function of extracellular matrix (ECM) receptors in distinct thymocyte subsets emerging during repopulation of the organ. The onset of regeneration was detected from day 2 to 3 postirradiation (P-lr), when a remarkable increase in the absolute counts of CD3-CD25(hi)CD44+ and CD3-CD25(in/hi)CD44- cells occurred. Enhanced expression of L-selectin, α4, and α5 integrin chains (L-sel(hi) α4(hi) α5(hi)) was also exhibited by these cells. This pattern of expression was maintained until the CD4+CD8+ (DP) young stage was achieved. Afterward, there was a general downregulation of these ECM receptors in DP as well as in CD4+ or CD8+ single positive (SP) thymocytes (L-sel(in) α4(in) α5(in)). In some recently generated SP cells, α4 expression was downregulated before the α5 chain, and L-selectin was upregulated in half of more mature cells. The expression of the α6 integrin chain was downregulated only in maturing CD4+ cells. Importantly, the increased expression of L- selectin and α4 and α5 chains in thymocytes was strongly correlated with their adhesiveness to thymic epithelial cells (TEC) in vitro. Blocking experiments with monoclonal antibody or peptides showed the following: (1) that the LDV rather than the REDV cell attachment motif in the IIIC segment of fibronectin is targeted by the α4 integrin during thymocyte/TEC-adhesion; (2) that the RGD motif of the 120-kD fragment of fibronectin, a target for α5 integrin, has a secondary role in this adhesion; and (3) that the YIGSR cell attachment motif of the β1 chain of laminin/merosin recognized by a nonintegrin receptor is not used for thymocyte adherence. In conclusion, our results show that an upregulated set of receptors endows CD25+ precursors and cells up to the young DP stage with a high capability of interacting with thymic ECM components.
The oil of Pterodon pubescens seeds (PpSO) is known for its cercaricidal and anti-inflammatory effects. Its anti-rheumatic activity was recently reported using mice with collagen II-induced arthritis treated with a hydroalcoholic extract of PpSO, mimicking the wine infusion used in popular medicine. In the present study, PpSO was tested for acute toxicity, mutagenic activity and cytotoxicity for human peripheral blood mononuclear cells (PBMNC). PpSO was obtained after seed extraction with 100% ethanol and evaporation. Cytotoxicity was estimated using the tetrazolium salt reduction test (MTT assay) by PBMNC (2.5 x 10(5) cells/ml) after exposure to 0.07, 0.7 and 7 microg PpSO/ml for 24 and 48 h. In the mutagenesis assay, the Salmonella/mammalian microsome assay was employed with or without metabolization. Acute toxicity was studied on 30 (n = 10/group) male DBA1/J mice (20 +/- 2 g) after a single oral dose of 2, 4, and 8 g PpSO/kg b.w. The animals were observed for 24 h, anesthetized, sacrificed and autopsied. The organs were processed for histopathology by staining with hematoxylin-eosin. The IC50 of PpSO to PBMNC in RPMI 1640 supplemented with 5% fetal calf serum (FCS) was 2 and 1 microg PpSO/ml after 24 and 48 h, respectively. The mutagenic test performed with or without metabolic activation of PpSO did not show mutagenic activity for the concentrations tested (7 and 70 microg/ml). Mouse mortality or significant signs of acute toxicity (ocular, cardiovascular, gastrointestinal, motor or respiratory signs) for the PpSO doses tested was not observed. The organs did not show any macroscopic alterations. Histopathologic analysis of the tissues also did not demonstrate any lesions. The present study provides data to classify PpSO as non-cytotoxic to PBMNC, non-mutagenic, and non-toxic after acute administration since the PpSO doses tested were extremely higher than those used by the population.
Echinodorus macrophyllus is a medicinal plant, popularly known in Brazil as "chapéu de couro", used to treat rheumatic diseases, which are usually characterized by exacerbated T and B lymphocyte response. We have evaluated the effects of the aqueous extract of Echinodorus macrophyllus (AEEm) on these cell functions, proliferation, and nitric oxide production. Mice treated orally for 7 days with AEEm had inhibited B cell antibody production (0.5mg/kg b.w.) and delayed type hypersensitivity (0.5 and 5mg/kg b.w.) mediated by T cells, reducing subcutaneous tissue leukocyte infiltration. AEEm inhibited, in vitro, NO production by stimulating J774 cells in a dose-dependent manner, with no cytotoxicity. We have demonstrated, for the first time, its immunosuppressive effect. This immunosuppressive effect supports a potential therapeutic use of AEEm to control exacerbated humoral and/or cellular immune response, as in autoimmune rheumatic diseases. However, it is important to be cautious about its indiscriminate popular use to avoid side effects, mainly in immunodeficiency diseases.