Chemical structure and effects of antioxidation and against alpha-glucosidase of natural polysaccharide from Glycyrrhiza inflata Batalin.

GIBP, a homogeneous polysaccharide extracted from Glycyrrhiza inflata Batalin with a molecular weight 1.96x10(3)kDa, had a triple helix structure, smooth and sheet-like structure. Comprehensive analysis showed that the main chain of GIBP was composed of alpha-D-1,4 linked glucose, branch points were composed of alpha-D-1,3,6 and alpha-D-1,2,3,6 linked glucoses, and side chains were composed of alpha-D-1,3 and beta-D-1,6 linked galactose, beta-L-1,2 linked arabinose, alpha-D-1,3 and beta-D-1,3 mannose. The scavenging abilities of GIBP (3mg/mL) against DPPH radical, OH radical, O(2)(-) radical and ABTS were 50.75+/-0.13% and 52.32+/-0.13, 25.84+/-0.35% and 44.57+/-0.15% and it also demonstrated an obvious dose-effect relationship. The inhibitory activity of alpha-glucosidase showed that the inhibitory effect of GIBP was enhanced with the increase of concentration. When the concentration reached 6mg/mL, the inhibition rate of alpha-glucosidase activity reached 64.77%. And the ka, kd and KD were 6.472x10(4) 1/Ms., 2.934x10(-3) 1/s and 4.534x10(-8)M.