α-Glucosidase Inhibitory Activity of Sophora japonica L.

In order to investigate the α-glucosidase inhibitory activity of Sophora japonica,the total extract acetone-water extract and those extracts including petroleum ether,ethyl acetate and n-BuOH were screened by α-glucosidase inhibitory model in vitro.The relationship between the inhibitory ratio and the extract concentration was assayed and the inhibitory kinetics was also investigated.The ethyl acetate extract(IC50=1.25 μg·mL-1),n-Butanol extract(IC50=16.14 μg·mL-1) and acetone-water extract(IC50=50.56 μg·mL-1)showed a strong inhibitory activity,which is higher than that of Acarbose(IC50=1081.27 μg·mL-1).All of them the shown noncompetitive type model on α-glucosidase with Ki value of 652.5 μg·mL-1,62.38 μg·mL-1 and 4.53 μg·mL-1.Quercetin(IC50=8.86 μg·mL-1) and kaempferol(IC50=73.69 μg·mL-1) were isolated from the ethyl acetate extract.The ethyl acetate extract can be further screened as the active fraction of the decreased postprandial blood glucose in vivo.The novelty of this work has been confirmed in the Technology Novelty Search Report No.CX200906242 provided by the library of Henan University on June 24,2009.