Hypoglycemic polysaccharides from the tuberous root of Liriope spicata.

Previous studies showed that the water extract and crude polysaccharides from the tuberous root of Liriope spicata var. prolifera showed high hypoglycemic and hypolipidemic activities. In the present study, two new water-soluble polysaccharides, named LSP1 and LSP2, were isolated from the active crude polysaccharides by DEAE-cellulose 52 and AB-8 macroporous resin chromatography and tested for their hypoglycemic effects. On the basis of the chemical and physical data obtained, LSP1 and LSP2 are two fructans with the molecular weights 3.20 and 4.29 kDa, respectively, which both have a backbone structure of beta-(1-->2)-fructosyl residues that branches at O-6 with fructosyl residues and terminates with a glucosyl residue and a fructosyl residue. Preliminary activity tests revealed that both LSP1 and LSP2 caused a significant decrease of the fasting blood glucose (FBG) and a significant improvement on glucose tolerance in type 2 diabetic mice. These results suggest that LSP1 and LSP2 show high potential to be explored as natural oral hypoglycemic agents.