Assessment of the genotoxic and antigenotoxic potential of crude extracts and fractions of Schwartzia brasiliensis (Choisy) Bedell ex Giraldo-Caas

Schwartzia brasiliensis (Marcgraviaceae) is a native Brazilian shrub species with neotropical distribution in shoal environments. Recent studies have revealed its medicinal potential for some human diseases; therefore, this study aimed to evaluate the genotoxic and antigenotoxic potential of extracts and fractions obtained from different organs of S. brasiliensis. To accomplish this, plant extracts at different concentrations (25, 125 and 250 µg/ml) were incubated with plasmid DNA, either alone, or in the presence of stannous chloride as a positive control. Samples were then examined to detect any plasmid strand breaks or the absence of such breaks, which would indicate protection of these molecules against stannous chloride-induced lesions. Methanol and aqueous extracts of leaves and stems showed the ability to withstand the effects of stannous chloride in that no DNA damage was observed. Moreover, no other extracts or fractions used in the experimental conditions assayed resulted in DNA damage. These findings suggest that S. brasiliensis has antigenotoxic properties, indicating, in turn, that its biological activities deserve further study given the medicinal relevance of this plant.   Key words: Medicinal plant, Marcgraviaceae, stannous chloride, flavonoids.