Comparative study of radical scavenger activities of crude extract and fractions from Cuphea carthagenensis leaves.

This study investigated the superoxide anion and hydroxyl radical scavenger properties, as well as the inhibition of lipid peroxidation by the crude hydroalcoholic extract (CE) and the butanolic (BF) and ethyl acetate (EAF) fractions of Cuphea carthagenensis leaves. In a enzymatic system of O2- production (xanthine/xanthine oxidase system) the CE, EAF and BF (0.1-100 microg ml(-1)) were effective at inhibiting both uric acid formation and NBT reduction by O2(-1). In the non-enzymatic system of O2- generation, the CE and fractions were effective only at the concentration of 100 microg ml(-1). The CE, EAF and BF were also evaluated for their ability to scavenge hydroxyl radicals and/or to chelate iron. The results showed that CE, BF and EAF from C. carthagenensis (0.1-100 microg ml(-1)) were able to inhibit deoxyribose degradation in a concentration-dependent manner. CE was more potent than the fractions. In a hydrophobic system, increasing concentrations of CE, EAF and BF (0.1-100 microg ml(-1)) caused graded inhibition of lipid peroxidation of rat liver homogenate. The EAF displayed the lowest median inhibitory concentration. The present study suggests that an extract (CE) and fractions (EAF and BF) from C. carthagenensis leaves are significant sources of phenolic compounds with antioxidant activity in vitro and may have important health effects, for example, in cardiovascular disease.