Biochemical analysis and hypoglycemic activity of a polysaccharide isolated from the fruit of Lycium barbarum L

Purification, characterization and hypoglycemic activities of polysaccharide from Lycium barbarum L. were investigated in this study. A water soluble polysaccharide (LBP) was obtained with ultrafiltration membranes separation, which was further purified by chromatography of DEAE cellulose column and Sephadex G-150 to get LBP3a and LBP3b. The high performance permeation chromatography (HPGPC) analysis showed that the average molecular weight (Mw) of LBP3b was 4.92 kDa. Monosaccharide composition analysis revealed that the LBP3b was comprised of mannose, rhamnose, glucose, galactose and xylose with a molar ratio of 5.52:5.11:28.06:1.00:1.70. The preliminary structure features of LBP3b were investigated by UV, FT-IR, NMR and SEM. In vitro cell experiments showed that LBP3b had significantly inhibited the absorption of glucose in a dose-dependent manner. The study showed that LBP3b had potential use as an anti-diabetic agent.