Effect of the hydro-methanolic (2:3) extract of the bark of Tectona grandis L. on the management of hyperglycemia and oxidative stress in streptozotocin-induced diabetes in rats

Abstract

Background: Natural products are considered to be effective and safe alternative treatment for the management of diabetes. So, the aim of this study was to fi nd out the antihyperglycemic and antioxidative effi cacy of the hydro-methanolic (2:3) extract of the bark of Tectona grandis in experimental diabetic rats. Materials and Methods: All chemicals were purchased from Sigma (USA). Diabetes was induced in rats by a single intramuscular injection of streptozotocin. The hydro-methanolic extract of the bark of T. grandis was prepared according to the standard method. The fasting blood glucose (FBG) level was measured by a glucometer. Activities of carbohydrate metabolic enzymes, antioxidant enzymes, and glycogen levels in liver, kidney, and skeletal muscular tissues were measured biochemically. Activities of serum glutamate oxaloacetate transaminase and serum glutamate pyruvate transaminase were assessed spectrophotometrically. Results: The FBG level, activities of carbohydrate metabolic enzymes like glucose-6-phosphatase, glucose-6-phosphate dehydrogenase, hexokinase in liver along with the quantity of glycogen in the liver and skeletal muscles were signifi cantly (P < 0.05) recovered by the extract compared to untreated diabetic rats. A signifi cant recovery (P < 0.05) was observed in the activities of antioxidant enzymes, i.e. catalase, peroxidase as well as the levels of conjugated diene and thiobarbituric acid reactive substances in the liver and kidney of extract-treated diabetic rats compared with untreated diabetic rats. Extract-treated diabetic animals also showed a signifi cant (P < 0.05) correction in the activities of glutamate oxaloacetate transaminase and glutamate pyruvate transaminase in the serum compared to untreated diabetic animals. The antidiabetic effi cacy of the extract was compared with glibenclamide. Conclusion: The results indicated that the hydro-methanolic extract of the bark of T. grandis has remedial effects on hyperglycemia and oxidative stress in diabetic rats.