The Extraction And Separation And Structural Identification Of Polysaccharides

In this paper,the coarse polysaccharide PP in Polygonum cuspidatum medicinal materials was extracted by water extract-alcohol precipitation.The DEAE-52 anion exchange chromatography and glucan gel chromatography were used to separate and purify the total polysaccharide,five homogeneous polysaccharide PP?-? were obtained.The physical and chemical properties of total polysaccharides and homogeneous polysaccharide were determined by spectrophotometry,the content of neutral sugar was determined by phenol-sulfuric acid method,the content of acid sugar was determined by between hydroxyl diphenyl method,and the content of protein was determined by coomassie brilliant blue method.The purity and molecular weight of homogeneous polysaccharide were measured by high exclusion chromatography method.The composition of monosaccharides were measured by PMP pre-column derivative method.The structures of three homogeneous polysaccharide were analyszed by IR?NMR and methylation.Inhibition of a-glycosidase activity of total polysaccharide and homogeneous polysaccharide was determined by a-glycosidase inhibitory activity assay.The molecular weights of five homogeneous polysaccharides were 8774,6502,5544,6502,5544 respectively.The content of neutral sugar and acid sugar increased,the content of protein decreased during the purification process.The content of neutral sugar,acid sugar,protein in Polygonum cuspidatum total polysaccharide PP were 54.52,9.35,10.01 respectively.Monosaccharide was mainly glucose,galactose,xylose,with the ratio of 23?2.2?1.The neutral sugar content of homogeneous polysaccharide was close to 100%,the acid sugar content was less and no protein content was detected.The composition of monosaccharide was mainly glucose by PMP pre-column derivation methord.The results showed that the structure of three homogeneous polysaccharides PP?-? all contained a large amount of ?-(1?4)glucoside keys,but the glycosidic bond type and proportion of repeat units were different.Active experiments showed that the Polygonum cuspidatum total polysaccharide had good ?-glycosidase enzyme inhibition activity,but homogeneous polysaccharides had almost no a-glycosidase enzyme inhibition activity,which indicated that the hypoglycemic activity of total PP due to the synergistic relationship with Polygonum cuspidatum pigment and protein.