Evaluation of the anti-diabetic effect of the methanol leaf extract and fractions of Dennettia tripetala G. Bak (Annonaceae) in alloxan- induced diabetic mice

Abstract

This study evaluated the anti-diabetic properties of the methanol extract and fractions of Dennettia tripetala leaves in alloxan diabetic rats. The crude  methanol extract (ME), n-hexane  (NF), ethyl acetate  (EAF), butanol  (BF) and water  (WF) fractions,  were tested for anti-diabetic activity in  alloxan-induced diabetic mice. The extracts and its fractions were screened for phytochemical constituents. Glibenclamide was used as the standard anti-diabetic treatment   Fasting blood glucose (FBG) levels were determined using a glucometer.  Lipid profile parameters were also assessed.  Histopathological examination of the pancreas was performed. The presence of glycosides, saponins, reducing sugars, fats and oil, alkaloids, carbohydrates, flavonoids, proteins and tannins were detected in ME, and the fractions. Treatment of the rats with the extract and its fractions reduced FBG levels significantly (p < 0.05) within 10 hours of acute treatment and 14 days short term treatment.  The highest reduction was by the crude extract,( ME 500 mg/kg) with percentage reduction of 62.89 %. The study revealed  significant (p < 0.05) reductions in serum triglyceride, serum cholesterol and LDL levels  by the extracts and its fractions  while a significant (p <  0.05) increase  in HDL levels was evident .  The effect of the extract and fractions on body weight indicated a moderate weight gain. Treatment with high dose of the extract and fractions (500 mg/kg) resulted in marked rejuvenation of the pancreatic β cells. The results of this study suggest that the leaves of Dennetia tripetala are endowed with potent anti-diabetic and antilipidemic properties.   Keywords: Dennetia tripetala, Antidiabetic, Alloxan, Lipid profile, Histopathplogy.