Avaliação da atividade genotóxica de extratos e do alcaloide indol-monoterpênico obtidos das raízes de Galianthe thalictroides (Rubiaceae)

Abstract

In family Rubiaceae species are found with food, economic importance and pharmacological, several species of this family, are considered by traditional medicine as therapeutic to treat various diseases. Galianthe thalictroides belongs to the subgenus Galianthe that is unique in South America, in Brazil, were described 38 species of which 28 are endemic, found in regions of Savannah and grassland. G. thalictroides roots have been used in traditional medicine to treat and prevent cancer and how there is no data in the literature about the effects of cytotoxic and genotoxic, the present study aims to evaluate these activities, using in vitro assays (MTT and Comet) and in vivo (SMART). The genotoxic activity of aqueous extracts prepared in the temperature 100°C (CGQ) and 4°C (CGF); fraction ethanolic (BETER); fraction chloroform (BGTRC-6) and indole-monoterpene alkaloid (RC6-2) have been assessed by testing for the detection of Somatic Mutation and Recombination – SMART. The MTT assay and Comet were performed only with indole-monoterpene alkaloid (RC6-2). The results obtained in the SMART assay indicate that the aqueous extracts (CGQ) and (CGF), in different concentrations, not produced statistically significant increases in frequency spots mutants, when compared with the negative control, not showing genotoxic activity. Because of this result the aqueous extract (CGQ) was associated with doxorubicin (DXR) for evaluation of antigenotoxic. The results indicated that this extract did not reduce the events mutacionais caused DXR, not showing activity antigenotoxic. However, the fraction ethanolic (BETER), once presented genotoxic potential metabolised, dose response. The fraction chloroform (BGTRC-6) in the concentrations of 0.4 and 0.8mg/mL caused mutagenic events, expressed by simple stains increase small, statistically significant when compared to the negative control, and cytotoxic concentration was 1.6mg/mL. The indole-monoterpene alkaloid (RC6-1) obtained from the fraction chloroform (BGTRC-6), presented significant events mutacionais, but did not exhibit cytotoxic concentrations evaluated in SMART. However, in testing of MTT the alkaloid (RC6-2) presented in the concentrations of cytotoxicity (10, 50 and 100μg/mL), however, no assay Comet caused DNA tape breaks, not showing genotoxic activity. The results obtained with the SMART assay, added to those found in the Comet assay, suggest that the alkaloid (RC6-2), is a spindle inhibitor, causing aneugenic, potent cytotoxic activity presented against tumor cells lineage of human hepatoma (HepG2) and has not caused mitotic recombination and mutagenic activity in somatic cells of Drosophila melanogaster.