Background: Extract of leaves from the Stevia rebaudiana Bertoni have been used in the traditional treatment of diabetes in Paraguay and Brazil. Stevia is a natural, non-caloric sweetener that is rich in pharmacologically important glycosides. These glycosides have many potential benefits in the mangment of the complications of diabetes. The treatment of type 2 diabetes mellitus (T2DM) is currently unsatisfactory. Therefore, we investigated the possible effects of stevia on treatment of T2DM when concurrently given with common antidiabetic agents in a trial to provide a safe and effective therapeutic antidiabetic combination.
Methods: Type 2 diabetes mellitus was induced in albino rats by IP administration of 230 mg/kg of nicotinamide (NA) followed by 65 mg/kg of streptozotocin (STZ). Albino rats were divided into five groups including normoglycemic, diabetic and three diabetic groups in which, the first was treated with aqueous extract of stevia (300 mg/kg), the second was treated with metformin (250 mg/kg), and the third was treated with a combination of metformin and stevia extract with the same doses for the period of 21 days. The rats were dissected; blood samples, liver and kidney were further used for detecting biochemical and histopathological changes. BG, insulin, adiponectin, TG, cholestrol, HDL, ALT, AST, urea, creatinine, total protein and TNFα levels were measured in sera. MDA concentration was detected in the liver and kidney.
Results: The aqueous extract of stevia significantly reduced the BG, triglycerides, cholesterol, ALT, AST, urea and creatinine levels in treated rats compared with diabetic rats (p<0.05). In addition to this, stevia surprisingly, increased insulin and adiponectin levels and decrease TNFα Level in treated rats (p<0.05). stevia extract also reduced the MDA concentration in the hepatic and renal tissue. Furthermore, stevia compensated for the histopathological damage in diabetic rats. All of these changes were more significant when the stevia extract was combined with metformin.
Conclusion: It is concluded that the stevia alone and/or in combination with other antidiabetic agents can be a new putitive drug used for the treatment of type 2 diabetes mellitus. Moreover, the combination of stevia and metformin has synergistic positive effects on type 2 diabetes mellitus.
