Chemical characterization of Callingcard Vine (Entada polystachya (L.) DC. var. polystachya) aqueous seed extract and evaluation of its cytotoxic, genotoxic and mutagenic properties.

Callingcard Vine (Entada polystachya (L.) DC. var. polystachya - Fabaceae) is a common plant in coastal thickets from western Mexico through Central America to Colombia and Brazil, especially in Amazon biome. It has been popularly used as a urinary burning reliever and diuretic. However, the plant chemical constituents are poorly understood and Entada spp. genotoxic potential have not been previously investigated. In the present study we determined the chemical composition of the aqueous E. polystachya crude seed extract (EPCSE) and evaluated the cytotoxic, genotoxic and mutagenic properties of EPCSE in Salmonella typhimurium and Chinese hamster fibroblast (V79) cells. Cytotoxic activity was also evaluated in tumor cell lines (HT29, MCF7 and U87) and non-malignant cells (MRC5). The chemical analysis by High Resolution Mass Spectrometry (HRMS) of EPCSE indicated the presence of saponin and chalcone. The results of the MTT and clonal survival assays suggest that EPCSE is cytotoxic to V79 cells. Survival analysis showed higher IC50 in non-tumor compared with tumor cell lines. EPCSE showed induction of DNA strand breaks as revealed by the alkaline comet assay and micronucleus test. Using the modified comet assay, it was possible to detect the induction of oxidative DNA base damage by EPCSE in V79 cells. Consistently, the extract induced increase lipid peroxidation (TBARS), superoxide dismutase (SOD) and catalase (CAT) activities in V79 cells. In addition, EPCSE induced mutations in S. typhimurium TA98 and TA100 strains, confirming a mutagenic potential. Taken together, our results suggest that EPCSE is cytotoxic and genotoxic to V79 cells and mutagenic to S. typhimurium. These properties can be related to the pro-oxidant ability of the extract and induction of DNA lesions. Additionally, EPCSE could inhibit the growth of tumor cells, especially human colorectal adenocarcinoma (HT29) cell line, and can constitute a possible source of antitumor natural agents.

Chemical characterization and cytotoxic, genotoxic, and mutagenic properties of Baccharis trinervis (Lam, Persoon) from Colombia and Brazil.

PHARMACOLOGY RELEVANCE: Baccharis trinervis (Lam, Persoon) leaves are used in the traditional medicine for the treatment of high fevers, edema, inflammation, sores and muscle cramps, snakebites and as antiseptic. AIM OF THE STUDY: To investigate the cytotoxic, genotoxic, and mutagenic effects of extracts and fractions of B. trinervis from Brazil and Colombia in Chinese Hamster Ovary (CHO) cells, and to examine the mutagenic activity in Salmonella typhimurium. MATERIAL AND METHODS: Aqueous extracts (AE) of aerial parts of B. trinervis from Brazil (B) and Colombia (C) were fractioned in ethyl acetate fraction (EAF), butanol extract (BF), and aqueous residue fraction (ARF). Qualitative chemical screening and determination of total flavonoid content were made. Identification of chemical constituents was performed by High Performance Liquid Chromatography (HPLC) and High Resolution Mass Spectrometry (HRMS). For the in vitro tests, CHO cells were treated for 3h with extracts and fractions. The cytotoxic activity was evaluated by clonal survival and 3-(4.5-dimethylthiazole-2-yl)-2.5-biphenyl tetrazolium bromide reduction assay (MTT). Genotoxic and mutagenic effects were evaluated by the alkaline comet assay and Cytokinesis-blockage micronucleus test (CBMN), respectively. Additionally, Salmonella/microsome assay was carried out to determinate the mutagenic effects in EAF from Brazil and Colombia. RESULTS: Phytochemical analyses indicated the presence of saponins and flavonoids. AE and EAF were the samples with the highest quantity of total flavonoids. HPLC showed the presence of luteolin only in AEC, and caffeic acid, ellagic acid, rosmarinic acid, and rutin were identified in AEB and AEC (AEC>AEB). The HRMS in positive mode of EAFB and EAFC showed presence of two carboxylic acids, coumarin, and two terpenoids. In addition, were identified one terpenoid and two carboxylic acids in AE, BF and ARF of B. trinervis from both countries in negative mode. Dose-dependent cytotoxic effects were observed in CHO cells treated with B. trinervis extracts and fractions by using clonal survival and MTT at concentrations higher than 0.05mg/mL. All the extracts and fractions induced DNA strand breaks in CHO cells with dose-dependent response, mostly EAFB and EAFC. The EAF from Brazil and Colombia showed mutagenic effect at 0.5mg/mL, while the other fractions did not show a significant difference in relation to the control. No mutagenic effects were found in EAF from both countries by the Salmonella/microsome assay. CONCLUSIONS: Cytotoxic and genotoxic effects were demonstrated in all extracts and fractions used, although only EAF showed mutagenic effects by CBMN, but not by Salmonella/microsome assay. Our results suggest that flavonoids, phenylpropanoids, coumarins, and diterpenes may be responsible for the cytotoxic, genotoxic and mutagenic effects observed.

Antimutagenic and antioxidant properties of the aqueous extracts of organic and conventional grapevine Vitis labrusca cv. Isabella leaves in V79 cells.

Grapes are one of the most commonly consumed fruit, in both fresh and processed forms; however, a significant amount is disposed of in the environment. Searching for a use of this waste, the antigenotoxic, antimutagenic, and antioxidant activities of aqueous extracts from organic and conventional Vitis labrusca leaves were determined using V79 cells as model. The antigenotoxic activity was analyzed by the alkaline comet assay using endonuclease III and formamidopyrimidine DNA glycosylase enzymes. The antimutagenic property was assessed through the micronucleus (MN) formation, and antioxidant activities were assessed using 2',7'-dichlorodihydrofluorescin diacetate (DCFH-DA) assay and 2,2-diphenyl-1-picrylhydrazyl (DPPH(●)) radical scavenging, as well as with superoxide dismutase (SOD) and catalase (CAT) activity assays. In addition, phenolic content and ascorbic acid levels of both extracts were determined. Data showed that both organic and conventional grapevine leaves extracts possessed antigenotoxic and antimutagenic properties. The extract of organic leaves significantly reduced intracellular reactive oxygen species (ROS) levels in V79 cells, and displayed greater ability for DPPH(●) scavenging and higher SOD and CAT activities than extract from conventional leaves. Further, the extract from organic leaves contained higher phenolic and ascorbic acid concentrations. In summary, extracts from organic and conventional grape leaves induced important in vitro biological effects.

Chemical Characterization and Cytotoxic Activity of Blueberry Extracts (cv. Misty) Cultivated in Brazil.

Vaccinium corymbosum (L.) varieties cultivation is relatively recent in Brazil, but its production has been intensified given its good adaptability to the Southern Brazil climate. Blueberries are a rich source of phenolic compounds and contain significant levels of anthocyanins, flavonols, chlorogenic acids, and procyanidins, which lead to different biological activities. Chemical identification of skin and whole hydroalcoholic blueberry extracts (ExtSB and ExtWB) revealed the presence of anthocyanins concentrated in the skin and others chemicals compounds as quercetin glycosides, proanthocyanins dimers, citric, and chlorogenic acid in the pulp. Selectivity for tumor cell lines (Hep-2, HeLa, HT-29) using ExtSB and ExtWB extracts was observed through MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay after 24 h of treatment when compared to nontumor cells (MRC-5). Morphological changes and late stages of apoptotic and necrosis process were seen in HT-29 cell line after ExtWB treatment, compared to nontumor cell line MRC-5. These results are in agreement with other studies that indicate the activity of compounds such as anthocyanins and other molecules found in Southern Highbush blueberry variety, attributed to promote beneficial effects on health that may respond as cytotoxic natural agent and contribute to cancer treatment.

Evaluation of Safety of Arrabidaea chica Verlot (Bignoniaceae), a Plant with Healing Properties.

Arrabidaea chica Verlot (Bignoniaceae) has been used as a medicinal herb to treat anemia, hemorrhage, inflammation, intestinal colic, hepatitis, and skin infections in the Brazilian Amazon region. Studies have demonstrated the healing properties of extracts obtained from A. chica leaves, which contain anthocyanins and flavonoids. However, few investigations have assessed the safe use of this plant species. In this study, mutagenic and genotoxic effects of a crude aqueous extract, a butanolic fraction, and aqueous waste from A. chica leaves were evaluated using the Salmonella/microsome assay in TA98, TA97a, TA100, TA102, and TA1535 strains and the alkaline comet assay in Chinese hamster ovary (CHO) cell culture with and without metabolic activation. The crude aqueous extract, butanolic fraction, and aqueous waste were not mutagenic in any of the Salmonella typhimurium strains tested, and showed negative responses for genotoxicity in CHO cells. High-performance liquid chromatography (HPLC) analysis indicated the presence of phenolic acids and flavonoids such as rutin and luteolin. The lack of mutagenic/genotoxic effects might be due to phytochemical composition with high concentrations of known anti-inflammatory compounds. Thus, the crude aqueous extract, butanolic fraction, and aqueous waste from A. chica leaves do not appear to pose short-term genotoxic risks.

Proteomic analysis identifies differentially expressed proteins after red propolis treatment in Hep-2 cells.

Here we investigated alterations in the protein profile of Hep-2 treated with red propolis using two-dimensional electrophoresis associated to mass spectrometry and apoptotic rates of cells treated with and without red propolis extracts through TUNEL and Annexin-V assays. A total of 325 spots were manually excised from the two-dimensional gel electrophoresis and 177 proteins were identified using LC-MS-MS. Among all proteins identified that presented differential expression, most were down-regulated in presence of red propolis extract at a concentration of 120 µg/mL (IC50): GRP78, PRDX2, LDHB, VIM and TUBA1A. Only two up-regulated proteins were identified in this study in the non-cytotoxic (6 µg/mL) red propolis treated group: RPLP0 and RAD23B. TUNEL staining assay showed a markedly increase in the mid- to late-stage apoptosis of Hep-2 cells induced by red propolis at concentrations of 60 and 120 µg/mL when compared with non-treated cells. The increase of late apoptosis was confirmed by in situ Annexin-V analysis in which red propolis extract induced late apoptosis in a dose-dependent manner. The differences in tumor cell protein profiles warrant further investigations including isolation of major bioactive compounds of red propolis in different cell lines using proteomics and molecular tests to validate the protein expression here observed.

Orange juice and cancer chemoprevention.

Orange juice (OJ) is among the most consumed fruit juices worldwide, and its chemopreventive action is fairly addressed in the literature. This review critically presents the available evidence linking OJ with cancer chemoprevention and on discussing the putative mechanisms and negative health effects. The chemopreventive action of OJ is related to its effect on metabolic enzymes and its antiinflammatory, cytoprotective/apoptotic, hormonal, cell signaling-modulating, antioxidant, and antigenotoxic effects. Most studies on OJ are in vitro, and few are conducted in vivo. Results from in vitro studies must be interpreted carefully because these findings do not consider in vivo bioavailability. However, such results are useful for studying the impact of different processing and storage methods on OJ's chemopreventive effect. Evidence of OJ's chemoprevention in humans is limited. OJ is antimutagenic in bacteria and antigenotoxic in humans and rodents. Studies using rodent cancer models showed that OJ is cancer chemopreventive, influencing either the induction stage or the promotion stage. The composition and, therefore, the chemopreventive action of OJ might be influenced by different cultivars, climates, extraction methods, packaging, storage temperatures, and shelf lives, among other factors. Epidemiological studies and randomized controlled intervention studies in humans evaluating the chemopreventive effect of OJ, taking into consideration variability in OJ composition, are needed.

The influence of micronutrients in cell culture: a reflection on viability and genomic stability.

Micronutrients, including minerals and vitamins, are indispensable to DNA metabolic pathways and thus are as important for life as macronutrients. Without the proper nutrients, genomic instability compromises homeostasis, leading to chronic diseases and certain types of cancer. Cell-culture media try to mimic the in vivo environment, providing in vitro models used to infer cells' responses to different stimuli. This review summarizes and discusses studies of cell-culture supplementation with micronutrients that can increase cell viability and genomic stability, with a particular focus on previous in vitro experiments. In these studies, the cell-culture media include certain vitamins and minerals at concentrations not equal to the physiological levels. In many common culture media, the sole source of micronutrients is fetal bovine serum (FBS), which contributes to only 5-10% of the media composition. Minimal attention has been dedicated to FBS composition, micronutrients in cell cultures as a whole, or the influence of micronutrients on the viability and genetics of cultured cells. Further studies better evaluating micronutrients' roles at a molecular level and influence on the genomic stability of cells are still needed.

Evaluation of the mutagenicity and genotoxicity of Arrabidaea chica Verlot (Bignoneaceae), an Amazon plant with medicinal properties.

Arrabidaea chica Verlot (Bignoniaceae) is an important folk medicine plant native to the Amazon region and used to treat anemia, hemorrhage, inflammation, intestinal colic, hepatitis, and skin affections. Although studies showed its therapeutic properties, little knowledge regarding genotoxic properties of this plant is available. The aim of this study was to determine the potential mutagenic and genotoxic/antigenotoxic effects of an A. chica chloroformic fraction (Ac-CF) obtained from leaves containing bioactive metabolites. The mutagenic effects were evaluated using the Salmonella mutagenicity assay, with TA98, TA97a, TA100, TA102, and TA1535 strains, with and without metabolic activation. In vivo mutagenic and genotoxic/antigenotoxic effects were investigated using the micronucleus (MN) test in bone marrow and alkaline comet assay in blood and liver after administration of 100, 500, or 1000 mg/kg Ac-CF in CF-1 mice by gavage (once a day for 3 d). In vitro antioxidant potential was evaluated using DPPH and xanthine/hypoxanthine assays. Ac-CF was not mutagenic in any of the Salmonella typhimurium strains tested and showed negative responses for mutagenicity and genotoxicity in mice. Further, Ac-CF displayed antigenotoxic effects by decreasing the oxidative DNA damage induced by hydrogen peroxide by greater than 50% in blood and liver. The antioxidant action detected in the in vitro assays demonstrated IC50 of 0.838 mg/ml in the xanthine/hypoxanthine assay and IC50 of 28.17 µg/ml in the DPPH assay. In conclusion, Ac-CF did not induce mutagenic and genotoxic effects and was able to protect DNA against oxidative damage in vivo, suggesting that this fraction may not pose genetic risks, although further toxicology assays are necessary.

Bioguided Fractionation Shows Cassia alata Extract to Inhibit Staphylococcus epidermidis and Pseudomonas aeruginosa Growth and Biofilm Formation.

Plant extracts have a long history to be used in folk medicine. Cassia alata extracts are known to exert antibacterial activity but details on compounds and mechanism of action remain poorly explored. We purified and concentrated the aqueous leaf extract of C. alata by reverse phase-solid phase extraction and screened the resulting CaRP extract for antimicrobial activity. CaRP extract exhibited antimicrobial activity for Pseudomonas aeruginosa, Staphylococcus epidermidis, S. aureus, and Bacillus subtilis. CaRP also inhibited biofilm formation of S. epidermidis and P. aeruginosa. Several bacterial growth-inhibiting compounds were detected when CaRP extract was fractionated by TLC chromatography coupled to bioautography agar overlay technique. HPLC chromatography of CaRP extract yielded 20 subfractions that were tested by bioautography for antimicrobial activity against S. aureus and S. epidermidis. Five bioactive fractions were detected and chemically characterized, using high-resolution mass spectrometry (qTOF-MS/MS). Six compounds from four fractions could be characterized as kaempferol, kaempferol-O-diglucoside, kaempferol-O-glucoside, quercetin-O-glucoside, rhein, and danthron. In the Salmonella/microsome assay CaRP showed weak mutagenicity (MI < 3) only in strain TA98, pointing to a frameshift mutation activity. These results indicate that C. alata leaf extract contains a minimum of 7 compounds with antimicrobial activity and that these together or as single substance are active in preventing formation of bacterial biofilm, indicating potential for therapeutic applications.

Neuroprotective and anticonvulsant effects of organic and conventional purple grape juices on seizures in Wistar rats induced by pentylenetetrazole.

Epilepsy is the most common neurological disorder worldwide. Studies have shown that recurrent seizures may increase the concentration of reactive oxygen species, which can lead to oxidative stress and neuronal damage. These seizures result in substantial deleterious effects on an individual's health. Organic and conventional grape juices are rich in polyphenols, compounds with important antioxidant activity. However, these juices could have differences in their polyphenol content. The aim of this study was to investigate the neuroprotective and anticonvulsant effects of organic and conventional grape juice treatments in Wistar rats against pentylenetetrazole (a convulsant drug)-induced damage. In addition, we evaluated potential behavioral changes in rats treated with the juices and the polyphenolic profile of those samples. Animals (n=16 in each group) received treatment with saline, organic or conventional grape juice for 17 days. On the eighteenth day, behavioral changes were evaluated by an open field test. Afterwards, half of the rats from each group received pentylenetetrazole and were observed for 30 min to evaluate possible seizure characteristics. The animals were subsequently killed by decapitation and their hippocampus, cerebellum and cerebral cortex tissues were isolated. The results of this study showed that neither organic nor conventional grape juice altered the behavior parameters, and no statistical differences were observed in the seizure characteristics of the groups. Nevertheless, both juice types were able to protect from lipid and protein oxidative damage, decrease nitric oxide content and increase enzymatic (superoxide dismutase and catalase) and non-enzymatic (sulfhydryl protein) antioxidant defenses in brain tissues following pentylenetetrazole-induced seizures. In general, organic juice showed superior results in each test, probably due to its higher polyphenol content relative to conventional juice. These results indicate that grape juices can provide further insight into natural neuroprotective compounds and may lead to the development of new therapeutic strategies for epileptic patients.

Antioxidant and antigenotoxic activities of purple grape juice--organic and conventional--in adult rats.

Oxidative damage to biomolecules occurs by the accumulation of molecular damage due to free radicals and/or a diminution of antioxidant protection. The aim of this study was to evaluate the protection of organic and conventional purple grape juices in brain, liver, and plasma from adult Wistar rats (7 months old) against the oxidative damage provoked by carbon tetrachloride (CCl(4)). Adult rats were divided into three groups (control, conventional purple grape juice, and organic purple grape juice). Half of the rats received CCl(4), and the other half received the vehicle (vegetable oil). The chemical analytical determination showed that the highest levels of total phenolic, resveratrol, and catechins were seen in organic purple grape juices. Considering the treatment groups, it was observed that in all tissues (brain structures and liver) and plasma, CCl(4) treatment increased the lipid peroxidation (LP) levels. Both grape juices were capable to reduce LP levels in cerebral cortex and hippocampus; however, in the striatum and substantia nigra only the organic grape juice reduced LP level. CCl(4) caused an increase in catalase activity in cerebral cortex, hippocampus, and substantia nigra and in superoxide dismutase activity in substantia nigra. This increase was reduced by both juices in substantia nigra and hippocampus structures (P < .05). In the alkaline version of the comet assay performed on whole blood, it was observed that CCl(4) was capable of inducing mainly DNA damage class 4 and 3 frequencies, which was significantly reduced in groups that received both purple grape juices. This implies that both grape juices have an important antigenotoxic activity.

Protective effects of three extracts from Antarctic plants against ultraviolet radiation in several biological models.

The photoprotective effect of the methanolic extracts of three Antarctic plant species - Deschampsia antarctica Desv., Colobanthus quitensis (Kunth) Bartl., and Polytrichum juniperinum Hedw. against UV-induced DNA damage was investigated in hamster lung fibroblasts (V79 cells) and in a biomonitor organism Helix aspersas, using comet assay. The protective, mutagenic, and antimutagenic profiles of these extracts were also evaluated using haploid strains of the simple eukaryote Saccharomyces cerevisiae, and antioxidant activity were investigated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay, as well as the hypoxanthine/xanthine oxidase assay. At the concentration range employed, the extracts were not cytotoxic or mutagenic to S. cerevisiae. In addition, the treatment with these extracts enhanced survival, and decreased induced reverse, frameshift, and forward mutations in a dose-response manner in all UVC doses employed. The plants extracts did not generate DNA strand breaks in V79 cells, and the treatment significantly decreased DNA damage induced by UVC. Extracts significantly decreased UVC-induced lipid peroxidation in V79 cells, showing a clear antioxidant property. Moreover, results of comet assay in V79 cells, employing Fpg, Endo III, and Endo V enzymes, demonstrated significant reduction of UVC-induced DNA damage after pre-incubation with these extracts. The treatment with all tested extracts were much less efficient against UVC-induced cytotoxicity in the yeast strain defective in photolyase as compared to the wild type strain, suggesting that this DNA repair pathway is stimulated by substances present in the extracts. All extracts showed a significant inhibitory effect in the hypoxanthine/xanthine oxidase assay, and they had the ability to scavenge DPPH. In H. aspersas, the treatment was able to protect against UVC-induced damage. In conclusion, D. antarctica, C. quitensis, and P. juniperinum extracts present photoprotective properties, which can be attributed to molecules, such as flavonoids and carotenoids, which act as UV-absorbing molecules and as antioxidants, as well as stimulate DNA-repair processes.

Mangifera indica extract (Vimang) impairs aversive memory without affecting open field behaviour or habituation in rats.

Vimang is an aqueous extract of Mangifera indica L, used in Cuba for the treatment of immunopathological disorders. Increasing evidence from preclinical studies indicates that Vimang displays antioxidant, antiallergic, analgesic and antiinflammatory actions. The present study investigated the effects of systemic administration of Vimang on behavioural outcomes of neurological function in rats. A single oral administration of Vimang produced an impairment of short- and long-term retention of memory for aversive training when given either 1 h pretraining or immediately posttraining, but not 8 h posttraining. Vimang did not affect open field behaviour or habituation. The results indicate that Vimang might induce deficits of emotionally motivated memory without affecting nonassociative memory, locomotion, exploratory behaviour or anxiety.

Protective effects of Hibiscus tiliaceus L. methanolic extract to V79 cells against cytotoxicity and genotoxicity induced by hydrogen peroxide and tert-butyl-hydroperoxide.

Plants of the genus Hibiscus thrives produce a diversity of molecules with bioactive properties. In a previous study of Hibiscus tiliaceus L. methanolic extract (HME) using bacteria and yeast, as test media, it has been shown that HME strongly inhibited the mutagenic action of H(2)O(2) or tert-butyl-hydroperoxide (t-BHP). Here, our interest is to evaluate the genotoxicity and the antigenotoxic/antimutagenic properties of HME using oxidative challenge with H(2)O(2) and t-BHP in V79 cells. We determined cytotoxicity using clonal survival assay; evaluated DNA damage using the comet assay and the micronucleus test in binucleated cells besides of the lipid peroxidation degree and the reduced glutathione content. We examined the ability of HME in quenching hydroxyl radical by means of a HPLC-based method utilizing the hypoxanthine/xanthine oxidase assay. At concentrations ranging from 0.001 to 0.1mg/mL, HME was not cytotoxic, genotoxic or mutagenic. Treatment with non-cytotoxic concentrations of HME increased cell survival after H(2)O(2) and t-BHP exposure and prevented DNA damage. The pre-treatment with HME also was able to decrease the mutagenic effect of these genotoxins, evaluated using the micronucleus test. HME prevented the increase in lipid peroxidation and decrease in GSH content in response to the oxidative challenge. Therefore, the ability in preventing against H(2)O(2)- and t-BHP-induced GSH depletion and lipid peroxidation was probably a major contribution to the cytoprotective effects. Moreover, HME acts as a hydroxyl radical scavenger. In summary, HME did not have a harmful or inhibitory effect on the growth of V79 cells and presented antioxidant activity, consequently, both antigenotoxic and antimutagenic effects against oxidative DNA damage.

Evaluation of genotoxicity and toxicity of water and sediment samples from a Brazilian stream influenced by tannery industries.

This paper reports results of genotoxicity and toxicity studies of water and sediment samples collected from the Estância Velha stream of southern Brazil, a stream transporting both domestic sewage and effluents from regional factories working in the leather industry. Three sites were selected: in the stream headwaters (Site 1), located downstream of an urban area (Site 2), and near the basin outfall (Site 3). Results obtained with Allium cepa showed no evidence of chromosomal mutation, either in water or in sediment, during winter or summer seasons, but samples collected below Site 1 showed high toxicity. Physical and chemical analyses showed high concentrations of pollutants at these sites. Ecotoxicity tests with Daphnia magna and Ceriodaphnia dubia measured toxicity in water from Sites 2 and 3 in summer 2004. A toxic effect on Hyalella azteca was only found in sediment from Site 3 during winter 2003 and summer 2004. The results suggest that the synergy among different compounds in domestic and industrial sewage discharges can make it difficult to maintain system stability.

Antioxidant and antimutagenic properties of Hibiscus tiliaceus L. methanolic extract.

The genus Hibiscus thrives in a variety of climates and produces a diversity of natural compounds with bioactive properties. We have studied the chemical composition and the in vivo antioxidant properties of Hibiscus tiliaceus L. methanolic flower extract, as well as its mutagenic/antimutagenic effects. Vitamin E and some stigmasterol derivatives that might confer an antioxidant effect to the extract were present. Treatment with this extract protected several Saccharomyces cerevisiae strains defective in antioxidant defenses against H2O2 and t-BOOH cytotoxicities, showing a clear antioxidant activity. The effect is the same for all strains used, independent of the antioxidant defense disrupted, suggesting that protection may be due to molecules that act as versatile and wide spectrum nonenzymatic antioxidants, such as vitamins or phytosterols. The extract was not mutagenic in either Salmonella typhimurium or S. cerevisiae and showed a significant antimutagenic action against oxidative mutagens in S. cerevisiae.

Effects of beta-carboline alkaloids on the object recognition task in mice.

beta-carboline alkaloids are found in several medicinal plants and display a variety of actions on the central nervous, muscular and cardiovascular systems. The aim of the present study was to evaluate the effects of systemic administration of beta-carboline alkaloids on object recognition in mice. Adult Swiss mice received an intra-peritoneal injection (i.p.) of alkaloids (1.0, 2.5 or 5.0 mg/kg) 30 min before training in an object recognition task. The fully aromatic beta-carbolines, harmine and harmol, induced an enhancement of short-term memory (STM) at all doses tested when compared to controls. Harmaline, a dihydro beta-carboline and inverse agonist of the MK-801 binding site on the N-methyl-d-aspartate (NMDA) receptor, also induced an enhancement of both short-term memory (STM) and long-term memory (LTM). These results demonstrate that systemic administration of beta-carboline alkaloids can improve object recognition memory in mice.

Influence of orange juice in the levels and in the genotoxicity of iron and copper.

World consumption of natural juices is increasing as a consequence of the human search for a healthier life. The juice production industry, especially for orange juice, is expanding in several countries and particularly in Brazil. Despite scientific data reporting beneficial properties derived from juice consumption, some components of juices have been identified as mutagenic or carcinogenic. Carcinogenic or genotoxic effects may be mediated by the interaction of juice components with transition metals or by sub-products of juice auto-oxidation. In this study, the mutagenic potential of orange juice and two metallic agents used in dietary supplementation, FeSO(4) and CuSO(4), were investigated using the comet assay in mouse blood cells (in vivo). Both metal compounds were genotoxic for eukaryotic cells after 24h treatment at the doses used. Significant damage repair was observed after 48h of treatment with the same compounds. Orange juice had a modulating effect on the action of metallic sulfates. In the case of iron treatment, the presence of the orange juice had a preventive, but not restorative, effect. On the other hand, in the case of copper treatment, the effects were both preventive and restorative. PIXE (particle induced X-ray emission) analysis indicated a positive correlation between DNA damage and the hepatic levels of iron and a negative correlation between whole blood copper and DNA damage. A negative correlation between hepatic iron and whole blood copper content was also seen in the treatment with both ferrous and cupric sulfates.

Mutagenic and antioxidant activities of Croton lechleri sap in biological systems.

The sap of Croton lechleri Muell.-Arg (Euphorbiaceae), called Dragon's blood, is used in folk medicine as a cicatrizant, anti-inflammatory and to treat cancer. In this research, the antioxidant activity of Croton lechleri sap was evaluated against the yeast Saccharomyces cerevisiae and against maize plantlets treated with the oxidative agents apomorphine and hydrogen peroxide. The mutagenic activity of the sap was also analyzed using the Salmonella/microsome assay (Salmonella typhimurium TA97a, TA98, TA100, TA102, TA1535) and in cells of the yeast Saccharomyces cerevisiae. The results showed that Croton lechleri sap possesses significant antioxidant activity against the oxidative damages induced by apomorphine in Saccharomyces cerevisiae under all the conditions studied. However, in the case of hydrogen peroxide, antioxidant activity of the sap was detected only in cells in the stationary phase of growth. The sap was also able to protect cells of the maize plantlets from the toxic effect of apomorphine. This sap showed mutagenic activity for strain TA1535 of Salmonella typhimurium in the presence of metabolic activation and a weak mutagenic activity for strain TA98. These strains detect base pair substitutions and frameshift mutations, respectively. Mutagenicity was also observed in a haploid Saccharomyces cerevisiae strain XV185-14c for the lys1-1, his1-7 locus-specific reversion and hom3-10 frameshift mutations.