Hypoglycaemic and amylase inhibitory activities of leaves of Spondias mombin Linn.

Suppressing the production of glucose by inhibiting a-amylase / a-glucosidase activity is one of the therapeutic approaches for decreasing postprandial hyperglycaemia and a strategy for evaluating antidiabetic activity. We investigated leaves of Spondias mombin because our previous ethnobotanical survey showed that it is used by traditional healers to manage diabetes in South West Nigeria. We report a bioactivity-guided study of S. mombin using glucose loading (1 g/kg) alloxan-induced diabetic rats and inhibition of a-amylase as basis for isolation of active constituents. Hyperglycaemia was induced in albino rats and blood glucose levels monitored for 180 mins using a glucometer. Powdered leaves were macerated with 80% Methanol. The active extract was fractionated on column chromatography packed with silica gel G6OA eluting with gradient mixtures of pet. ether and ethylacetate. The most active a-amylase inhibiting fraction was purified on thin layer chromatography (TLC) and pure compound identified by spectroscopy. Peak decrease in blood glucose of 41.4% (p < 0.05) was recorded after 60 mins. This activity-guided study produced an active TLC band (69.8% amylase inhibition, p < 0.05) from which a-sitosterol was characterized as the main inhibitor. This is first report of hypoglycaemic and amylase inhibitory activities of S. mombin. The role of phytosterols in control of diabetes mellitus is discussed. This study justifies the ethnopharmacological use of this species in recipes for management of diabetes mellitus.