Antidiabetic and Antioxidant Effects of Vernonia amygdalina (Bitter Leaf) Extract in Streptozotocin-Induced Diabetic Rats

Background: Vernonia amygdalina, commonly known as bitter leaf and widely consumed in South East and South South Nigeria, has been attributed antidiabetic properties in traditional medicine. Scientific validation of these properties through rigorous animal models is needed to support its therapeutic application or development. This study evaluated the antidiabetic and antioxidant effects of V. amygdalina aqueous leaf extract in streptozotocin (STZ)-induced diabetic rats. Methods: Diabetes was induced in male Wistar rats via a single intraperitoneal injection of STZ (60 mg/kg). Forty-two rats were grouped into: normal control, diabetic control, metformin-treated (200 mg/kg), and three extract-treated groups (100, 250, 500 mg/kg orally for 28 days). Fasting blood glucose was monitored weekly. At termination, serum insulin, lipid profile, and antioxidant enzymes (SOD, CAT, GPx, MDA) were assayed. Histopathological examination of pancreatic tissue was performed. Results: V. amygdalina extract at 500 mg/kg significantly reduced fasting blood glucose by 47 percent from week 2 (p less than 0.01). Insulin levels increased dose-dependently. Dyslipidaemia was significantly reversed, and antioxidant enzyme activity was restored to near-normal levels. Pancreatic histology showed partial regeneration of islet cells at the highest dose. Conclusion: V. amygdalina demonstrates significant antidiabetic and antioxidant properties in STZ-induced diabetes. These findings provide scientific support for further phytopharmaceutical development. Keywords: Vernonia amygdalina, antidiabetic, streptozotocin, oxidative stress, herbal pharmacology