alpha-Glycosidase inhibitory activity of hexagalloylglucose from the gallsof Quercus infectoria

Hexagalloylglucose (3-O-digalloyl-1,2,4,6-tetra-O-galloyl-beta-D-glucose), which was isolated from the methanol extract of the galls of Quercus infect oria, significantly inhibited alpha-glycosidases such as sucrase, maltase a nd isomaltase. Its inhibitory activity was comparable to acarbose being use d as a hypoglycemic agent, while the inhibitory activity on alpha-amylase w as approximately 10 times lower than that of acarbose. The results indicate that, when compared to acarbose, hexagalloylglucose might reduce the side effects by reducing inhibition of alpha-amylase.