Abstract
Efficacy of several plant extracts in the clinical research for modulating oxidative stress correlated with diabetes mellitus (DM) is well documented. In the present study, we investigated the in vitro antioxidant activity, toxicity, and anti-diabetic activity of methanolic extract of Hippophae salicifolia leaves in normal and alloxan-induced diabetic wistar rats. H. salicifolia leaves were found to be rich in antioxidants. The acute toxicity test of methanolic extract of H. salicifolia leaves revealed that the median lethal dose (LD(50)) was found to be 3.92 g/kg body weight in mice. Administration of H. salicifolia leaves at 200 mg/kg and 400 mg/kg in alloxan-induced diabetic rats illustrated significant reduction (22% and 39%, respectively) in fasting blood glucose compared to diabetic control. Both the doses were found to be effective when compared to diabetic rats. The Hippophae-treated diabetic rats showed significant increase in the endogenous antioxidant enzymes, superoxide dismutase (50% and 74%, respectively), glutathione peroxidase (57% and 41%, respectively) and decrease in malondialdehyde (33% and 15%, respectively) levels. These results suggested that the methanolic leaf extract of H. salicifolia enhanced the antioxidant defence against reactive oxygen species produced under hyperglycaemic conditions.