Hypoglycemic Activity of the Extract and Fractions of Anthocleista vogelii (Planch) Stem Bark

Purpose: To investigate the hypoglycemic effect of the methanol extract and fractions of Anthocleista vogelii stem bark. Methods: The methanol extract of A. vogelii stem bark (ME) was subjected to gradient chromatographic separation using four solvents - chloroform, ethyl acetate, acetone and water - to afford the respective fractions - CF, EF, AF and WF. ME was administered orally to normoglycemic rats at 200 and 400 mg/kg and fasting blood glucose (FBG) monitored for 6 h. Alloxan-induced diabetic rats were also treated orally with ME and the various fractions (each at 200 mg/kg and 400 mg/kg), with glibenclamide (0.2 mg/kg) and normal saline (2 ml/kg) serving as standard and control, respectively. ME and the fractions were also subjected to phytochemical analysis following standard procedures. Results: The extract possessed comparable hypoglycemic effect to glibenclamide in healthy rats. The extract and its fractions also exhibited significant (p < 0.05) antidiabetic effect. ME, CF, EF, AF and WF each at 400 mg/kg, produced maximum reduction (64.10, 38.53, 36.50, 60.77 and 12.79 %, respectively) in FBG of the animals after 6 h, compared to 53.77 % for glibenclamide. Presence of alkaloids, carbohydrates, reducing sugars, saponins, flavonoids, glycosides, steroids, terpenoids, tannins, proteins, fats and oils were observed in ME, EF and AF. Alkaloids, flavonoids, steroids, terpenoids, fats and oil were also detected in CF while WF showed the presence of carbohydrates, glycosides, saponins and proteins. Conclusion: This study establishes the antidiabetic activity of the stem bark of A. vogelii. The acetone fraction is the most active antidiabetic fraction.