Aqueous bark extract of Cinnamomum zeylanicum: A potential therapeutic agent for streptozotocin- induced type 1 diabetes mellitus (T1DM) rats

Abstract

Purpose: To investigate the anti-diabetic, hepatoprotective and lipid homeostatic activity of Cinnamomum zeylanicum aqueous bark extract on streptozotocin (STZ)-induced type-I diabetic rats. Methods: The animals were divided into three groups (n = 6). of normal rats; streptozotocin-induced diabetic rats; and diabetic rats treated with 200 mg/kg of the aqueous bark extract, respectively. Treatment was via the oral route for 15 days. Various biochemical parameters, including lipid profile and glycogen biosynthesis were analysed. Similarly, differential regulation and expression of glucose homeostatic enzymes were evaluated in order to validate the anti-diabetic activity of the extract. Results: Total cholesterol (TC), triglyceride (TG), LDL-cholesterol (LDL) and VLDL-cholesterol (VLDL) levels decreased significantly (p < 0.05) in the diabetic animals by 12.5, 23.86, 14.96 and 20 %, respectively, compared to their initial values. The extract increased HDL-cholesterol (HDL) and tissue glycogen levels by 25.0 and 172.3 %, respectively, in diabetic rats. Similarly, differential regulation and expression of glucose homeostatic enzymes, namely, glucokinase (GK), glucose-6-phosphatase (G6Pase), phosphoenol pyruvate carboxykinase (PEPCK), glucose-6-phosphate dehydrogenase (G-6- PDH) and Insulin II (Ins II), showed significant improvement upon extract treatment in STZ-induced diabetic rats. Conclusion: These results demonstrate the anti-diabetic, and hypolipidemic activities of Cinnamomum zeylanicum aqueous bark extract in diabetic rats. © Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria.