Screening for Free Radical Scavenging Activities of Extracts from Coccinia grandis and Centella asiatica
Abstract
Background : Coccinia grandis and Centella asistica are tropical vegetables and acclaimed in Thai folk medicind for treatment of various diseases. The mechanisms responsible for their pharmacological effects remain uncertain. The antioxidant activities. Are proposed to play role in th mechanism of action.
Objectives : To investigate the antioxidant activities of C.grandis and C.asiatica.
Method : Free radical scavenging activity was assessed by 1, 1 – Diphenyl – 2 picrylhydrazyl (DPPH) assay. Total antioxidant power (FRAP) assay. Intracellular oxygen radicals scavenging effect in rats peritoneal macrophages was evaluated by using fluorescent dichlorofluorescein probe.
Results: C.grandis and C.asiatica extracts showed ability to scavenge DPPH radical with EC 50 values of 164.78+5.63 and 172.33+9.13 ug/ml, respectively. It appeared that their potency were about 100 folds less than that of ascorbic acid and trolox. Total antioxidant power of wxtracts, as assayed by FRAP method revealed that 1 mg of C. Grandis extract had reducing power comparable to ascorbic acid 8.23 + 0.64 ug or FeCl2 11.4+0.92 ug. In addition, both plant extracts at the concentration of 100, 300 ug/ma and tiron 10, 30 ug/ml significantly decreased the formation of oxygen radicals generated in rat peritoneal macrophages.
Conclusins : Although both extracts had relatively low reducing power in these in vitro assays, however, thir antioxidant effects as shown in peritoneal macrophages may be of significance and worthwhile for further investigation.
