ABSTRACT. Salacia crassifolia (Mart. Ex. Schult.) G. Don., popularly known in Brazil as "bacupari", "cascudo", and "saputá", is a shrub of the Celastraceae family that is unique to the Brazilian Cerrado region. In folk medicine, this plant has been mainly used to treat skin cancer and gastric ulcers. In the present study, the genotoxic, cytotoxic, antigenotoxic, and anticytotoxic effects of S. crassifolia stem bark fractions (hexane, ethyl acetate, and hydroalcoholic extracts) were evaluated using the mouse bone marrow micronucleus test. Our results showed that none of the S. crassifolia fractions led to a significant increase in the frequency of micronucleated polychromatic erythrocytes (MNPCE) (P > 0.05), suggesting the absence of genotoxicity. In the antigenotoxicity assessment, a significant decrease in the MNPCE frequency was observed in all fractions of this plant (P < 0.05), demonstrating its protective action against genotoxicity induced by mitomycin C (MMC), which was used as the positive control. Only the hexane fraction of S. crassifolia significantly decreased the poly-and normochromatic erythrocyte ratio (PCE/NCE) in all doses tested (P < 0.05), demonstrating its cytotoxic activity. In association with MMC, both ethyl acetate and hydroalcoholic fractions significantly increased the PCE/NCE ratio in almost all doses tested (P < 0.05), demonstrating the protective action of S. crassifolia against the cytotoxic effect of the positive control. In contrast, the hexane fraction presented a significant decrease in the PCE/NCE ratio in all treatments (P < 0.05), demonstrating an increase in this plant's cytotoxicity in mouse bone marrow cells.

ABSTRACT. Cassia angustifolia Vahl. (senna) is commonly used in selfmedication and is frequently used to treat intestine constipation. A previous study involving bacteria and plasmid DNA suggested the possible toxicity of the aqueous extract of senna (SAE). The aim of this study was to extend the knowledge concerning SAE genotoxicity mechanisms because of its widespread use and its risks to human health. We investigated the impact of SAE on nuclear DNA and on the stability of mitochondrial DNA in Saccharomyces cerevisiae (wt, ogg1, msh6, and ogg1msh6) strains, monitoring the formation of petite mutants. Our results demonstrated that SAE specifically increased Can R mutagenesis only in the msh6 mutant, supporting the view that SAE can induce misincorporation errors in DNA. We observed a significant increase in the frequency of petite colonies in all studied strains. Our data indicate that SAE has genotoxic activity towards both mitochondrial and nuclear DNA.