Anti-diabetic activity evaluation of a polysaccharide extracted from Gynostemma pentaphyllum

In current study, a polysaccharide (GPP) was successfully extracted from Gynostemma pentaphyllum herb. Monosaccharide composition of GPP was rhamnose, arabinose, galactose, glucose, xylose, mannose, galacturonic acid and glucuronic acid in a molar ratio of 4.11: 734: 1331: 20.99:1.07: 0.91: 4.75: 036. Molecular weight and polydispersity (Mw/Mn) of GPP were 4.070 x 10(4) Da and 1.037, respectively. Primary structure features of GPP were determined to be a polysaccharide by FT-IR and NMR. Fasting blood sugar of diabetic mice decreased from 17.56 mmol/L to 7.42 mmol/L by orally administration of 0.5 mL GPP (1 mg/mL) for 30 days. GPP exhibited a dose-dependent inhibition effect on alpha-glucosidase activity. Moreover, GPP could inhibit the glucose absorption and affect the protein expression of GLUT2, but not the protein expression of SGLT1. These results indicated GPP could be used as an effective ingredient to prevent and cure diabetes. (C) 2018 Published by Elsevier B.V.