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Yam roots and other plants from Dioscorea genus have cultural, nutritional and economic importance to tropical and subtropical regions and have a great amount of diosgenin in its composition. In the present study the cytotoxic, genotoxic and mutagenic potential of diosgenin on HepG2 cells was investigated. Cytotoxicity was assessed using MTT and clonogenic assay. Genotoxic and mutagenic effects were performed using single cell gel electrophoresis and cytokinesis-block micronucleus assay, respectively. A reduction on cell viability was observed due to diosgenin treatment at concentrations higher than 30 μM. A genotoxic effect was shown by comet assay and CBMN. Besides, an increase in micronucleus frequency along with a significant cytostatic effect were observed. Diosgenin elicited DNA damage on HepG2 cells which could not be efficiently repaired contributing to the mutagenic effect observed. Those results suggest that diosgenin deleterious effect could take place through genetic instability, fact that affects the normal cell cycle, leading to cell's death., (Copyright © 2018. Published by Elsevier Ltd.)

Medicinal plants have been used in primary healthcare since the earliest days of humankind. Turnera subulata and Spondias mombin × Spondias tuberosa are widely used in the Brazilian Northeast to treat several diseases. The aim of this study was to evaluate the genotoxic effects of the leaf extracts of these species by the somatic mutation and recombination test in the somatic cells of Drosophila melanogaster wings. The experiments were performed using standard and high-bioactivation cross and three concentrations of the test substance [aqueous extract (AET and AES) at 5.0, 10.0, and 20.0 mg/mL and ethanolic extract (EET and EES) and ethyl acetate fraction (EAFT and EAFS) at 0.625, 1.25, and 2.5 mg/mL]. Results indicated that the extracts and fractions induced spontaneous frequencies of mutant spots in both D. melanogaster crosses. Nevertheless, the highest concentrations of the tested plant chemical agents were responsible for the statistically significant genotypic effect. T. subulata and S. mombin × S. tuberosa displayed genotoxic effect under the experimental conditions. The results from this study are crucial as they indicated the deleterious and side effects, considering the indiscriminate use of the extracts of these plants for disease treatment.

Lucrécia city, known to harbor a high cancer rate, is located in a semiarid region characterized by the presence of mineral reservoirs, facing a high exposure to metal and natural radioactivity. The present study aimed to assess the environmental scenario at a semiarid region located in Northeastern Brazil. Metal concentration, alpha and beta radiation, and cyanobacteria content in tap water along with indoor radon and gamma emitters (U, K and Th) concentrations were measured. In addition, mutagenic and nuclear instability effects were assessed using buccal micronucleus cytome assay. The study included five samplings corresponding to a period between 2007 and 2009. Drinking water from Lucrécia city presented levels of Mn, Ni and Cr along with cyanobacteria in concentrations one to four times higher than regulatory guidelines considered. Furthermore, high levels of all the tested radionuclides were found. A high percentage of the houses included in this study presented indoor radon concentrations over 100 Bq m -3 . The mean annual effective dose from Lucrécia houses was six times higher than observed in a control region. The levels of exposure in most of the Lucrécia houses were classified as middle to high. A significant mutagenic effect, represented as an increase of micronuclei (MN) frequency and nuclear abnormalities as nuclear buds (NB), binucleated cells (BN), and pyknotic cells (PYC) were found. The results obtained highlight the role of high background radioactivity on the observed mutagenic effect and could help to explain the exacerbated cancer rate reported in this locality., (Copyright © 2016. Published by Elsevier Ltd.)

The present study evaluated the mutagenic potential of surface water from the Lucrecia dam. The Tradescantia-micronucleus (Trad-MCN) test and CBMN assay in human peripheral blood lymphocytes were applied, corresponding to an in vivo and in vitro system, respectively. Heavy metals and some physicochemical properties were also measured. Water samples were collected in November 2009 (dry season) and May 2010 (rainy season) at three different points. Results of both assays for raw water showed positive responses for the points analyzed when compared to the negative control. The CBMN assay showed that diluted water was still able to induce a significant increase in micronucleus frequency. For both assays, the highest mean MN was observed in the dry season. Chemical analyses detected an increase in heavy metal levels at the sampling points and in the different seasons. These findings indicate the presence of genotoxins, such as heavy metals, in the water, which may be affecting the entire ecosystem, as well as human health. More prolonged monitoring is recommended in order to better characterize this public water supply.

The aim of this work was to analyze the genotoxicity in surface water from the Pitimbú River (Natal, Brazil) using a neotropical species Crenicichla menezesi as bioindicator for in situ evaluation. The genotoxicity was analyzed using the micronucleus (MN) and comet assays in erythrocytes. The animals were collected from five sites of the river. A significant increase of MN frequency and comet class L1 to L4 were observed only in specimens collected from three sampling sites (SS3, SS4 and SS5) located into urban areas. These same sites also presented high metals concentration. Correlation of DNA damage and concentrations of Cu (Spearman r=0.8080), Cr (Spearman r=0.9772), and Ni (Spearman r=0.9909) were observed. These data indicate the presence of genotoxic agents. Moreover the C. menezesi species showed to be a good indicator for prompt analyses since this species presents sedentary and carnivore habits., (Copyright © 2010 Elsevier B.V. All rights reserved.)

The micronucleus (MN) and nuclear abnormality (NA) tests were employed to evaluate the genotoxic potential of the Lucrecia dam (RN, Brazil) located in a semi-arid region and influenced by crop irrigation and irregular rainfall. The analyses of these water samples demonstrated the presence of several cyanobacteria as well as metals and radioactivity. The Nile Tilapia (Oreochromis niloticus) was used for micronucleus and nuclear abnormality assays and analysis of metal concentrations in gills and liver samples. Genotoxic assays in source water fish showed a significant increase in the frequency of nuclear damage (MN and NA) in relation to the negative control group. In conclusion, the results obtained with water surface and biological samples from the Lucrecia dam suggest that this important water resource contains a number of chemical and microbiological pollutants with genotoxic potential and that these substances may be compromising the species inhabiting this ecosystem. Particular care must be taken to prevent further degradation of this water supply. Capsule: A battery of assay was successfully applied to assess the water quality of Lucrecia dam from a Northeastern region of Brazil., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

In this study, the widespread environmental pollutants 1-nitronaphthalene (1NN), 1,5-dinitronaphthalene (1,5DNN), 2-nitrofluorene (2NF) and 9-nitroanthracene (9NA), were investigated for genotoxicity in the wing somatic mutation and recombination test (SMART) of Drosophila--using the high bioactivation (HB) cross. Our in vivo experiments demonstrated that all compounds assessed induced genetic toxicity, causing increased incidence of homologous somatic recombination. 2NF, 9NA and 1NN mutant clone induction is almost exclusively related to somatic recombination, although 1,5DNN-clone induction depends on both mutagenic and recombinagenic events. 1NN has the highest recombinagenic activity (approximately 100%), followed by 2NF (approximately 77%), 9NA (approximately 75%) and 1,5DNN (33%). 1NN is the compound with the strongest genotoxicity, with 9NA being approximately 40 times less potent than the former and 2NF and 1,5DNN approximately 333 times less potent than 1NN. The evidence indicating that the major effect observed in this study is an increased frequency of mitotic recombination emphasizes another hazard that could be associated to NPAHs--the increment in homologous recombination (HR).

The present study evaluates the clastogenic and/or aneugenic potential of maté (Ilex paraguariensis) - previously tested for the presence of 48 organophosphorous pesticides - in the culture of human lymphocytes in the absence of exogenous metabolic activation. Peripheral blood was obtained once from three healthy female donors for lymphocyte cell cultures. The cultures were treated with maté infusion (filtered in sterilized sartorius filter with a 0.22 mm pore membrane), distilled water (negative control), and 6 microg/ml bleomycin (positive control). For each experimental person, 3000 binucleated cells (BN) from two independent cultures (1000 cells from replicate cultures) were scored for the presence of micronuclei (MN). No statistical differences between maté infusion concentrations were observed: 1400 microg/ml (0.001+/-0.002), 700 microg/ml (0.0006+/-0.0015), 350 microg/ml (0.002+/-0.002), 175 microg/ml (0.002+/-0.003) and negative control (0.001+/-0.001). The present findings show that there is no clastogenic or/and aneugenic basis underlying maté action in the CBMN assay.

Vanillin (VA) modulates the genotoxicity of chemical and physical agents in a complex manner. Previous studies indicate that VA inhibits the mutagenicity but increases the mitotic homologous recombination caused by at least some genotoxic agents. In the present study, we have evaluated the effects of VA on the repair of lethal damage produced by three genotoxins, N-ethyl-N-nitrosourea (ENU), ethyl methanesulfonate (EMS), and mitomycin C (MMC), using the DNA repair test (DRT) in Drosophila melanogaster. VA, 0.25% and 0.5% (w/v), increased the toxicity of MMC and EMS in repair-deficient flies, as measured by a decrease in the proportion of male to female progeny in the DRT; sex ratios decreased from 18-48% for MMC and 21-97% for EMS. These effects may be caused by the inhibition of nonhomologous DNA end joining caused by VA. In contrast to the results with MMC and EMS, VA protected against the lethality of ENU in repair-defective flies, as measured by a 43-207% increase in the survival of male flies in the DRT. It was inferred that the protective effect was due to VA modulating stages prior to the induction of ENU lesions in DNA, including modulating the antioxidant properties of VA and/or to its interference with the metabolic activation and/or detoxification of specific genotoxins. The results from this study indicate that the characterization of VA as a promising agent for preventing damage to genes and chromosomes should be tempered by observations that VA can increase the toxicity of chemical agents.

Mutagenic and recombinagenic activity of surface waters in the Guaíba Hydrographic Region (RS, Brazil) was investigated using the SMART in Drosophila melanogaster. Two positive results in Caí River (September 2000 and August 2001) and in Taquari River (August 2001 and February 2002)--linked to direct recombinagenic toxicants were observed. In Jacuí samples, an indirect mutagenic and recombinagenic action was detected in a September 2000 collection and a direct recombinational activity was observed in February 2002. Also in February 2002--samples from Dilúvio Brook and Guaíba Lake (GPC) were able to induce wing spots by mitotic recombinagenesis. The former sampling site showed toxicants to have a direct action, and the latter an increment in mitotic recombination that depended on metabolic action. The SMART wing test shows that all positive responses were mainly related to homologous mitotic recombination.