In-vitro alpha-amylase and glucosidase inhibitory potential of leaf hexane, ethyl acetate and methanol fractions from Pterocarpus soyauxii Taub

Diabetes mellitus is a critical clinical condition characterized by hyperglycemia in which an accelerated amount of glucose circulates in the blood plasma. This work attempts to evaluate the α-amylase and α-glucosidase inhibitory activities of hexane, ethyl acetate and methanol fractions of Pterocarpus soyauxii at varying concentrations. 1.0 kg of milled leaf sample was first soaked in 5 L of methanol to obtain a percentage yield of 12%. The assay was carried out using standard procedures. The following IC50 values were obtained in the α-amylase inhibition: 0.0395, 0.05995, and 0.0509 mg/mL for hexane, ethyl acetate, and methanol, respectively compared to the standard drug acarbos (0.00812 mg/ mL). A dose-dependent increase in percentage inhibition was obtained for α-glucosidase with IC50 values of 0.052, 0.059, and 0.065 mg/mL for respective fractions compared to the standard drug used (0.0017 mg/mL). The hexane fraction showed the greatest percentage inhibition for both α-amylase and α-glucosidase, while appreciable inhibition activity was observed in other fractions. The Nigerian Pterocarpus soyauxii has been identified for the first time as a very potent anti-diabetic agent useful in management of postprandial hyperglycemia and related therapeutic interventions.