Evaluation of Antidiabetic and Antioxidant Effects of Seabuckthorn (Hippophae rhamnoides L.) in Streptozotocin-Nicotinamide Induced Diabetic Rats

Abstract

The present investigation was undertaken to evaluate the antidiabetic and antioxidant effect of Seabuckthorn (Hippophae rhamnoides L.) in streptozotocin-nicotinamide induced type-2 diabetic rats. Experimental diabetes was induced by single intraperitonial injection of streptozotocin (60mg/kg), 15 minutes after i.p. administration of 120mg/kg nicotinamide. Seabuckthorn was orally administered to normal and diabetic rats for a period of 21 days. Fasting plasma glucose, glycosylated haemoglobin, thiobarbituric acid reactive substances and tissue glutathione in pancreas were estimated following the established procedures to assess the pancreatic function. Biochemical observations were supplemented with histological examination of pancreatic tissue. Fasting plasma glucose, glycosylated haemoglobin, TBARS were significantly (P<0.05) increased, whereas insulin, total haemoglobin, protein levels and glutathione were decreased significantly (P<0.05) in diabetic rats. Oral administration of Seabuckthorn to diabetic rats significantly decreased (P<0.05) fasting plasma glucose, glycosylated haemoglobin and increased insulin, haemoglobin and protein levels. Administration of Seabuckthorn also decreased TBARS and increased the non- enzymatic antioxidants significantly (P<0.05). An oral glucose tolerance test was also performed in which we found a significant improvement in glucose tolerance in rats treated with Seabuckthorn. Treatment of normal rats with Seabuckthorn did not significantly (P<0.05) alter any of the parameters studied. Degenerative changes of pancreatic beta cells in STZ- diabetic rats were minimized to near normal morphology by administration of Seabuckthorn as evident by histological examination. The results of the study indicate the role of oxidative stress in the induction of diabetes and suggest a protective effect of Seabuckthorn in this animal model.