Avaliação do efeito modulador da levedura de cerveja (Saccharomyces cerevisiae M.) sobre a genotoxicidade induzida pela doxorrubicina em Drosophila melanogaster

O teste de mutação e recombinação somática (SMART) em Drosophila melanogaster foi utilizado para avaliar o potencial de genotoxicidade e antigenotoxicidade do produto comercial levedura de cerveja (Saccharomyces cerevisiae). Este composto é uma mistura complexa usada pela população para manter o equilíbrio orgânico por ser rico em vitaminas do complexo B, proteínas, minerais e carboidratos. O SMART foi usado na versão padrão (ST - fêmeas flr3 x machos mwh) para verificar compostos de ação direta e, na versão alta bioativação (HB - fêmeas ORR;flr3 x machos mwh), para verificar compostos de ação indireta, em três diferentes quantidades de levedura de cerveja (10,0%, 20,0% ou 40,0% p / p). A essas quantidades foram adicionadas 1,5g de purê de batata e hidratados com 5 ml de água ou doxorrubicina (DXR) (0,125 mg / mL). As larvas obtidas dos cruzamentos ST e HB foram submetidos ao tratamento crônico e feita a análise das asas dos adultos emergentes. A levedura de cerveja não foi genotóxica em ambos os cruzamentos, porém, possui efeitos moduladores sobre a genotoxicidade da DXR, como também exibiu uma atividade sinergistica. Portanto, são necessárias mais pesquisas para determinar os possíveis riscos que podem estar associados com a exposição de organismos a esta mistura complexa

Antigenotoxic effects of Mandevilla velutina (Gentianales, Apocynaceae) crude extract on cyclophosphamide-induced micronuclei in Swiss mice and urethane-induced somatic mutation and recombination in Drosophila melanogaster

A Mandevilla velutina crude extract was investigated using the mouse micronucleus test (MNT) and the Drosophila melanogaster somatic mutation and recombination test (SMART) using standard (ST) and high bioactivation (HB) crosses. The MNT used 10 mg, 20 mg or 40 mg per 100 g of body weight (bw) of extract with and without 0.2 mg per 100 g bw peritoneal cyclophosphamide. There was no genotoxicity in the negative control or extract only groups and, compared to the cyclophosphamide control, there was a significant reduction in micronucleated polychromatic erythrocytes in all the groups given extract plus cyclophosphamide. For SMART larvae were fed 5 or 10 mg mL-1 of extract for seven days with and without 0.89 mg mL-1 of urethane given on day seven. The ST and HB flies showed no significant differences in spots between the negative control and the extract only groups. The number of urethane-induced spots was reduced by the highest concentration of extract for the ST flies and by both concentrations of extract for the HB flies. The results suggest that M. velutina extract is not genotoxic but is antigenotoxic.ISSN:1415-4757ISSN:1678-468

Modulatory effects of the antioxidant ascorbic acid on the direct genotoxicity of doxorubicin in somatic cells of Drosophila melanogaster

In this study two different crosses involving the wing cell markers mwh and flr³ (standard (ST) cross and high bioactivation (HB) cross, the latter being characterized by a high constitutive level of cytochrome P450 which leads to an increased sensitivity to a number of promutagens and procarcinogens) were used to investigate the modulatory effects of ascorbic acid (AA) combined with the antitumor agent doxorubicin (DXR) in Drosophila melanogaster. We observed that the two different concentrations of AA (50 or 100 mM) had no effect on spots frequencies, while DXR treatments (0.2 or 0.4 mM) gave positive results for all types of spots, when compared to negative control. For marker-heterozygous (MH) flies, a protective effect was observed with the lower concentration of AA (50 mM) that was able to statistically decrease the frequency of spots induced by DXR (0.2 mM), while an enhanced frequency of spots induced by DXR was observed with the higher concentration of AA (100 mM), when compared to DXR treatment (p < 0.05). These results suggest that AA may interfere with free radicals generated by DXR and with other possible reactive metabolites. The efficiency of AA in protecting the somatic cells of D. melanogaster against mutation and recombination induced by DXR is dependent on the dose used and the protection is directly related to the activity of cytochrome P450 enzymes