ABSTRACT
Objective:To study the scavenging activity of macroporous resin isolate of gynostemma pentaphyllum on free radical DPPH. Methods:The extract of gynostemma pentaphyllum via water boiling and precipitation with ethanol was separated by macro-porous resin respectively eluted by water, 40% ethanol and 80% ethanol to obtain the corresponding isolates. The antioxidant activity of the three isolates was determined by free radical DPPH systematic method, and the results were compared with that of gallic acid and ascorbic acid. Results: The 50% inhibitory concentration on free radical DPPH of the three isolates was 0. 081 2, 0. 028 7 and 0. 541 0 g·L-1 ,respectively. The 40% ethanol isolate had the highest saponins concentration. Conclusion:The macroporous resin i-solate with different solvent all shows antioxidant activity and the 40% ethanol isolate has the strongest effect, suggesting saponins may be the active substances for the lipid-lowering, hypoglycemic and free radical scavenging activities.