Efeito de extratos de folhas de barbatimão sobre o dano oxidativo e a genotoxicidade induzida por ciclofosfamida

Abstract

The aim of the present study was to determine the antioxidant and antigenotoxic effect of leaf extracts of Styphnodendron adstringens (“barbatimão”). The aqueous (AEB), water fraction (WFB) and ethanolic (EEB) extracts of leaves were obtained. We analyzed the antioxidant activity in vitro and in vivo and the effect against a genotoxic agent, cyclophosphamide (CP), of the extracts. The extracts presented high content of phenolic compounds, flavonoids and proanthocyanidins. All of the extracts tested exhibit antioxidant activity. The total antioxidant capacity of the extracts was: 147.85±12.68, 124.36 ± 7.18 and 148.64 ± 8.41 mg ascorbic acid/g extract, for AEB, WFB and EEB respectively. The free radical DPPH scavenging activity of the extracts was concentration-dependent and the maximum activity was achieved with 62 μg/mL. The extracts presented Fe3+reducing capacity similar to ascorbic acid and higher than BHT and it was also concentration-dependent. The maximum reducing power was achieved with 250 mg/mL. The AEB and EEB were most efficient in brain, reducing TBARS formation while the WFB was most active in liver, decreasing protein oxidation. As for DNA fragmentation, it can be seen that CP induced apoptosis, confirmed by the DNA ladder pattern. The AEB neither induce apoptosis nor protected cells from the effects of CP. The WFB was antigenotoxic, as it did not induce apoptosis and protected cells from the apoptotic effect of CP. The EEB induced necrosis, as seen by the intense DNA lesion (smear). In conclusion all extracts presented antioxidant activity and WFB was antigenotoxic. WFB may be useful as cancer chemopreventive and/or anticarcinogenic agent.