Ginsenoside Rg1 alleviates the postprandial blood glucose by inhibiting α-glucosidase

One of the most effective therapeutic proposals for type 2 diabetes mellitus (T2DM) is regulation of postprandial blood glucose (PBG) level by inhibiting α-glucosidases. In this study, we firstly investigated the influence of ginsenoside Rg1 (Rg1) on activity of α-glucosidase in vitro. The results revealed that Rg1 had a reversible inhibition on α-glucosidase activity in an uncompetitive manner. Fluorescence spectrum and circular dichroism (CD) analysis indicated that the stable complex between Rg1 and α-glucosidase was mainly formed by hydrogen bonds and hydrophobic forces. In addition, the anti-hyperglycemic effect of Rg1 was confirmed by the sucrose tolerance test in normal and db/db mice. Caco-2 monolayer cell model further emphasized that decreasing effect of Rg1 on PBG may be achieved by reducing glucose uptake and transport which is accounted for inhibition of α-glucosidase. Taken together, those results suggested that Rg1 may be used as a promising α-glucosidase inhibitor to decrease PBG.