Effects of Aqueous Extract ofMyrtus Communis L. Leaves on Streptozotocin-Induced Diabetic Rats

Background: Leaves, oil and fruit of Myrtus communis L. (MC) have therapeutic effects on diabetes mellitus (DM). Aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) are liver enzymes associated with hepatic injury caused by DM. Aims: In this study, we aimed to investigate the antidiabetic and antioxidant effects of the aqueous extract of MC leaves on normal and diabetic rats induced with streptozotocin (STZ). Material &Methods: A total of thirty rats divided into six groups as each composed of five rats were used. DM was induced by a single 40 mg/kg dose of STZ in diabetic control group (Group II) and DM groups (Group IV,V and VI). Three different doses (150, 300 and 600 mg/kg) of aqueous extract of MC leaves were administered to the DM groups for 14 days. Serum samples and liver homogenates were obtainedin order to determine serum glucose levels and superoxide dismutase (SOD) activity, glutathione (GSH) and malondialdehyde levels (MDA), serum alanine aminotransferase (ALT), alkaline phosphatase (ALP), and aspartate aminotransferase (AST) levels. Serum glucose levels were determined by a commercial glucose monitor with disposable dry reagent strips. SerumSOD activity, GSH and MDA levels were measured by commercial ELISA kits. Serum ALT, ALP, and AST levels were measured by biochemical and immune-enzyme analyzers with respective standard kits. Results: Serum glucose, AST, ALT and ALP levels were reduced by MC administration in all diabetic groups. MC administration provided significance increment in SOD activity and GSH level, and significant reduction in MDA levels compared to controls (p<0.05) in all diabetic groups for all parameters, being highest at the dose of 600 mg/kg (p<0.001). Conclusion: Aqueous extracts of MC leaves at the doses of 150, 300 and 600 mg/kg decreased blood glucose, serum ALT, AST and ALP levels. Besides, all extracts have antioxidant effects being highest at 600 mg/kg dose. Key Words: Myrtus communis L., leaves, diabetes mellitus, antioxidant