Characterization and hypoglycemic effect of a polysaccharide extracted from the fruit of Lycium barbarum L.

Diabetes mellitus is a group of complicated metabolic disorders characterized by high blood glucose level and inappropriate insulin secreting capacity due to decreased glucose metabolism and pancreatic beta cell mass or dysfunction of beta cells. Thus, improving glucose metabolism and preserving beta cell mass and function might be useful for the treatment of diabetes. In this study, a novel acidic polysaccharide LBP-s-1 extracted from Lycium barbarum L. was obtained by purification using macroporous resin and ion-exchanged column. Monosaccharide composition analysis indicated that LBP-s-1 was comprised of rhamnose, arabinose, xylose, mannose, glucose, galactose, galacturonic acid in the molar ratio of 1.00:8.34:1.25:1.26:1.91:7.05:15.28. The preliminary structure features of LBP-s-1 were investigated by FT-IR, H-1 NMR and C-13 NMR. In vitro and in vivo hypoglycemic experiments showed that LBP-s-1 had significant hypoglycemic effects and insulin-sensitizing activity through increasing glucose metabolism and insulin secretion and promoting pancreatic beta cell proliferation. Preliminary mechanisms were also elucidated. (C) 2013 Elsevier Ltd. All rights reserved.