Evaluation of Anti-Diabetic and Anti-lipidemic Activities of Aqueous Leaf Extract of Millettia aboensis and Its Effect on Pancreatic Histology of Alloxan-Induced Diabetic Rats

Abstract

Plants provide a potential source of anti-diabetic drugs and are widely used in several traditional systems of medicine to prevent diabetes. This study evaluated the anti-diabetic and anti-lipidemic activities of oral administration of aqueous leaf extract of Milletia aboensis in, and its effect on pancreatic histology of, alloxan-induced diabetic rats. Eighty rats were grouped into eight based on average body weights. Diabetes similar to that of type 1 in human was induced by a single intra-peritoneal injection of alloxan monohydrate a -diabetogenic agent (160 mg kg-1). After 120 hours of alloxan injection, the rats from Groups 2 – 8 were confirmed diabetic having baseline fasting blood sugar levels >8.5mmol/L. Group 1 served as normal control. The extract was administered twice daily for 21 days at doses of 500 mg kg-1 – 2500 mg kg-1 in Groups 4 – 8. Group 2 was treated with a standard diabetic drug, ‘Metformin’, while Group 3 (untreated and negative control) was diabetic with increased Total cholesterol (CHOL), low density lipoproteins (LDL), triacylglycerol (TAG) levels and reduced high density lipoproteins (HDL) level throughout the experiment. Glucose was assayed for on the 7th, 14th and 21st day while CHOL, HDL, LDL, and triglyceride were assayed on the 21st day. A significant reduction (p<0.05) in the fasting blood glucose levels of rats in Groups 4-8 was observed when compared to the normal control. Similarly, there was a significant decrease (p<0.05) in TAG and LDL and a significant increase (p<0.05) in HDL levels in groups treated with the extract when compared to Group 1 (normal control). A photomicrograph of the pancreatic cells was taken before and after treatment with aqueous leaf extract. The photomicrograph before treatment showed atrophic pancreatic islet with vacuolations which indicates significant damaged Islets of langerhans in the beta cells. After treatment the photomicrograph indicates significant cell regeneration and repair. The present investigation suggests that leaf extract of M. aboensis exhibits anti-diabetic and anti-lipidemic activities and positively affected pancreatic functions in alloxan-induced diabetes rats.