The Molecular Mechanism And Hypoglycemic Activity Of Exo-Polysaccharide Produced By Grifola Frondosa

Grifola frondosa is an important fungal research resources. Variety of active substances can be isolated and purified from the fruity body, fermentation solution and mycelium. And the hpyerglycemic effect of exo-polysaccharide (GFP) extracted from the liquid-cultured myceliumuse after deep liquid-ferment had been identified.However, there were not report about GFP of its hpyerglycemic effect through establishment of insulin rensistance cell model.In this study, the exo-polysaccharide was extracted by alcohol sedimentation after strain activating and fermentation culture. Component separation was conducted by Sephadex G-200 and ultrafiltration. One fraction (named GFP-2) was obtained after the inhibition of each segment on a-glucosidase.GFP-2 was a single-component and its molecular weight was about 45300Da which confirmed by sephadex G-75 and HPLC.The physicochemical properties of GFP-2 were investigated that GFP-2 was an non-starch polysaccharide contained beta type glyconsidic bond and pyranose ring. This paper is to study the high hpyerglycemic effect and relieve insulin rensistance of GFP-2 on an vitro HepG2 cell model induced by high concentration of insulin by means of pharmacological and molecular biological methods.The results of Western blot analysis showed that the cell model treated with GFP-2 activated the insulin receptor protein (IRS)in the cell membrane and promote 110-β one subunit of phosphatidyl inositol 3-kinase to transfer and induce a obvious activation of phosphorylated-AktSer473 which have an inhibition of glycogen synthase kinase (GSK-3). The down-regulation of GSK-3 will stimulate glycogen metabolism and synthetize glycogen. At the same time, detected the irreversible enzyme-catalyst of gluconeogenesis (glucose-6-phosphatase), glucolysis (pyruvate kinase) and the content of glycogen.The conclusion is that GFP-2 can obviously increase the metabolic rate of glucose and change to glycogen for storage and bring down blood sugar. This paper illustrated the ameliorative effeets of GFF-2 on insulin resistance of HepG2 cell model, providing for for exploiting auxiliary drug of hpyerglycemic and health prorection food.