Antioxidant and Antidiabetic Activity of Aqueous Ethanolic Extract of Momordica charantia L. (Cucurbitaceaevar Guti) Fruit in Streptozotocin (STZ) Induced Diabetes Rats

Background and Objective: Type 2 diabetes is caused by the failure of beta cells ($-cells) to compensate for insulin resistance.This leads to hyperglycaemia, which can in turn exert deleterious effects on $ cells.The current study aimed to assess the antioxidant activity and hypoglycemic effects of aqueous ethanolic extract of Momordica charantia L. fruit (MCE) in normal and streptozotocin induced diabetic rats.Moreover, the interacting effects of co-administration of MCE on the antidiabetic activity of metformin and glibenclamide were evaluated.Materials and Methods: Total phenolic content, DPPH radical-scavenging activity and oral glucose tolerance test (OGTT) for aqueous ethanolic extract of Momordica charantia L. fruit (MCE) were assayed.Albino rats were divided into five groups of six rats in each group: group 1 (NR): Normal rats, group 2 (DR): Diabetic rats, group 3 (DR administrated MCE at dose of 50 mg kgG 1 ), group 4 (DR administrated 600 µg kgG 1 glibenclamide and) lastly group 5 (DR administrated MCE at dose of 50 mg kgG 1 plus glibenclamide at dose of 600 µg kgG 1 ).The daily oral treatment was administered in between 08.00-09.00AM for 4 weeks.Data were analyzed by using Excel (Microsoft Office 2007) and SPSS Version 18.0.Results: The total phenolic content of aqueous ethanolic extract of MCE was 673.9 mg GAE/100 g dry extract.The aqueous ethanolic extract of MCE exhibited 78.08% DPPH radical-scavenging activity at 500 µg mLG 1 which was comparable to that of Butylatedhydroxytoluene (BHT) as positive standard at a concentration of 500 µg mLG 1 (86.1%).The results of the main experiment indicate that the highest reductions (20.68, 35.54, 38.18 and 55.09) were observed for those diabetic rats treated with a combination of aqueous ethanolic extract of MCE (50 mg kgG 1 ) and 600 µg kgG 1 of glibenclamide on 7th, 15th, 22nd and 30th day of treatment, respectively.Administration of MCE induced a significant protective effect reflected in the reductions of the serum levels of (AST and ALT), as well as kidney functions (urea and creatinine) in diabetic rats.Conclusion: These findings indicated that the hypoglycemic efficiency of the aqueous ethanolic extract of MCE at dose of 50 mg kgG 1 was similar to the glibenclamide (600 µg kgG 1 ).