Effect of Astragalus membranaceus (Fisch) Bunge extract on streptozocin-induced diabetic in rats

Purpose: To investigate the effect of Astragalus membranaceus (Fisch.) Bunge. extract (AMBE) on streptozotocin-induced diabetic rats. Methods: The aqueous extract of AMB was obtained by steeping the dried Astragalus membranaceus (Fisch.) Bunge. in water at 60 degrees C three times, each for 1 h, before first drying in an oven at 100 degrees C and then freeze-drying the last extract thus obtained. Diabete model rats was induced by a single intraperitoneal injection of a freshly prepared solution of streptozotocin (50 mg/kg). The rats were randomly divided into 6 groups of ten rats each: negative control group, normal control group, reference group (glibenclamide1 mg/kg body weight) as well as AMB extract groups, namely, 40, 80 and 160 mg/ kg body weight. Antihyperglycemic effect was measured by blood glucose and plasma insulin levels. Oxidative stress was evaluated in liver and kidney by antioxidant markers, viz, lipidperoxidation (LPO), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx) and catalase (CAT), while blood serum levels of creatinine and urea were also determined in both diabetic control and treated rats. Results: Compared with diabetic rats, oral administration of AMBE at a concentration of 160 mg/ kg daily for 30 days showed a significant decrease in fasting blood glucose (109.438 +/- 3.52, p < 0.05) and increased insulin level (13.96 +/- 0.74, p < 0.05). Furthermore, it significantly reduced biochemical parameters (serum creatinine, 0.86 +/- 0.29, p < 0.05) and serum urea (45.14 +/- 1.79, p < 0.05). The treatment also resulted in significant increase in GSH (49.21 +/- 2.59, p < 0.05), GPx (11.96 +/- 1.16, p < 0.05), SOD (14.13 +/- 0.49, p < 0.05), CAT (83.25 +/- 3.14, p < 0.05) level in the liver and kidney of diabetic rats. Conclusion: The results suggest that AMBE may effectively normalize impaired antioxidant status in streptozotocin-induced diabetes in a dose-dependent manner. AMBE has a protective effect against lipid peroxidation by scavenging free radicals and is thus capable of reducing the risk of diabetic complications.