The antihyperglycemic effect of Bridelia ndellensis ethanol extract and its fractions is mediated by an insulinotropic action

Backgroung: Bridelia ndellensis (Euphorbiaceae) is used as a traditional plant treatment of diabetes. The aim of the present study was to investigate the mechanism involved in the antihyperglycemic effects of this plant. Methods: An intestinal perfusion technique was used to study the effect of the ethanol extract of B. ndellensis on the intestinal absorption of glucose in normal rats fasted for 36 h. The effect of the extract (50 and 100 mg/kg) on Insulin secretion was evaluated using BRIN-BD11 pancreatic cells. Results: In a perfused rat intestinal preparation in situ, the plant extract at a concentration of 5 mg/ml did not show any inhibitory effects on glucose absorption when compared with control animals. Ouabain which is an inhibitor of glucose transport across the small intestine significantly (p < 0.001) decreased the glucose absorption during the whole perfusion period compared with the control group. On the other hand, the plant extract inhibited the gastrointestinal motility induced by Barium sulphate milk in rats. The ethanol extract of B. ndellensis at concentrations of 50 and100mg/ml stimulated in a concentration-dependent manner the insulin secretion from BRIN-BD11 cells in vitro. The induction of insulin release was significantly different when compared to control with the concentration of 100 μg/ml (P < 0.001). Alanine (10 mM) used as positive control, significantly (p < 0.001) stimulated insulin release from BRIN-BD11 cells. Conclusion: The present study has revealed that B. ndellensis ethanol extract stimulates insulin secretion and does not affect the glucose absorption, and it has suggested that the antihyperglycemic effects of B. ndellensis is partly mediated by the stimulation of insulin secretion.