Modulatory effects of Gymnema montanum leaf extract on alloxan-induced oxidative stress in Wistar rats

OBJECTIVES: In light of evidence that some complications of diabetes mellitus may be caused or exacerbated by oxidative damage, we investigated the effect of Gymnenia montanum leaf extract (GLEt) on tissue antioxidant defense systems in alloxan-induced diabetes in rats. METHODS: GLEt was administered orally at a doses of 50, 100, and 200 mg/kg of body weight for 30 d, after which liver and kidney tissues were assayed for the degree of lipid peroxidation by means of markers, reduced glutathione content and activities of catalase, superoxide dismutase, glutathione peroxidase, and glutathione-S-transferase. RESULTS: Treatment of diabetic rats with GLEt increased the antioxidant levels. Liver and kidney from diabetic animals exhibited disturbances in antioxidant defense when compared with normal rats. GLEt at a dose of 200 mg/kg of body weight exhibited a significant effect as compared with 50 and 100 mg/kg of body weight. These effects were compared with glibenclamide, a reference drug. CONCLUSIONS: It may be concluded that, in diabetes, liver and kidney tissues are more vulnerable to oxidative stress and show increased lipid peroxidation. The antioxidant responsiveness mediated by G. montanum may be anticipated to have biological significance in eliminating reactive free radicals that may otherwise affect normal cell functioning and provide a scientific rationale for the use of G. montanum as an antidiabetic plant. (C) Elsevier Inc. 2004.