Evaluation of Antidiabetic Potential of Gymnema Sylvestre and Metformin Combination in Streptozotocin-Induced Diabetic Rats

BACKGROUND: Type 2 diabetes mellitus (T2DM) is a progressive metabolic disorder characterized by insulin resistance and hyperglycemia. Although metformin remains a first-line therapy, interest in plant-based adjuncts like Gymnemasylvestre (GS) is increasing due to their potential antidiabetic properties. OBJECTIVES: The study aimed to assess the efficacy of the combination of Gymnemasylvestre (GS) and metformin in reducing blood glucose levels and body weight in streptozotocin-induced diabetic rats. Additionally, it sought to compare the effectiveness of this combination therapy with metformin alone in achieving glycemic control and weight reduction. The investigation also explored the potential benefits of the combination treatment on lipid profile and renal function, providing a broader understanding of its therapeutic impact in managing type 2 diabetes mellitus. METHOD: Thirty male Sprague Dawley rats (150 ± 20 g) were divided into five groups: normal control, diabetic control, metformin-treated, GS-treated, and combination-treated. T2DM was induced by administering a high-fat diet for 21 days followed by two low-dose intraperitoneal injections of streptozotocin (25 mg/kg, five days apart). Rats with fasting blood glucose (FBG) ≥250 mg/dL were selected for treatment, which continued for 28 days. RESULTS: All treatment groups showed significant improvements in biochemical parameters compared to diabetic controls (p < 0.05). Metformin and combination therapy groups demonstrated greater reductions in FBG, cholesterol, creatinine, and HbA1c levels. While GS alone had modest antidiabetic effects, its combination with metformin enhanced efficacy, especially in glycemic control and lipid profile. Metformin alone showed superior effects on renal function. CONCLUSION: Gymnemasylvestre exhibits antidiabetic activity, which is amplified in combination with metformin. Although metformin alone remains more effective, the combination therapy offers additional benefits in T2DM management.