Antioxidant activity of Hypericum hookerianum Wight and Arn

Methanolic extracts of leaf, root, flower and aerial parts of Hypericum hookerianum were assessed for in vitro antioxidant activity using eight different models. Total antioxidant capacity, phenol and flavanol content of the extracts were determined to correlate between their antioxidant activity and constituents present therein. Results of in vitro antioxidant study suggest that extracts from leaf and flower have strong antioxidant potential. Leaf extract (100 & 200 mg kg(-1) b.w. p.o.) that showed maximum activity was selected for in vivo antioxidant studies using a CCl(4)-intoxicated rat model. The effects of extracts on lipid peroxidation (LPO), superoxide dismutase (SOD) and catalase (CAT) in serum and liver homogenate were analysed. CCl(4) treatment caused a significant increase in the level of CAT and SOD and a significant decrease in the level of LPO in a dose-dependent manner when compared to CCl(4) treated control. The results indicate the strong antioxidant nature of H. hookerianum leaf extract.