Avaliação do potencial antioxidante dos extratos de Uncaria tomentosa IN VITRO

Abstract

Considering the relationship between oxidative stress and the pathogenesis of human diseases, and of the presence of compounds with antioxidant activities in vegetable extracts, the objective of the present study was to investigate the mechanism(s) involved in the antioxidant potential of Uncaria tomentosa in vitro. For that, the scavenging activity against picrilhidrazil o 1'- 1 ' difenil- 2' (DPPH) and nitric oxide (NO) radicals; degradation of deoxyribose; interaction with the chemical redox of iron ions and effect on lipid peroxidation (measured as TBARS) were performed. Furthermore, phenolic compounds and flavonoids were measured by colorimetric methods. Our results clearly indicate that the aqueous and etanolic extracts of U. tomentosa present significant (p<0,05) scavenging activity against different free radicals. Moreover, the extracts presented significant (p<0,05) interaction with the redox chemistry of iron ions and prevents Fe2+-induced lipid peroxidation. In general, the effects of the plant extracts varies depending from the solvent used to prepare the extract (if etanolic or aqueous), the concentration and assay used. Considering our results, we suggest that, at least in part, U. tomentosa's antioxidant properties in vitro may be related with its ability to scavenge different free radical species and due to its capacity to interact with the redox chemistry of iron ions, thus interfering with the free radical generation systems.