Extraction, Structural Investigation Of Polysaccharides And Oligosaccharides From Polygonatum Sibiricum Redoute

Polygonatum is dried root of Liliacous plant, it has been used as food and medicine for thousands years of history. It is well-known for anti-bacterial, antiviral, anti-tumor, and anti-aging function, it is also efficacious in reducing glucose and lipids of blood. Based on previous study, this project explored the chemical constitution and structural characteristics of pure polysaccharide and oligosaccharide compounds of Polygonatum.The precipitate and supernatant fluid are extracted from Polygonatum by the method of water extraction-alcohol precipitation, 3 polysaccharides could be isolated from the precipitate degreased in consequence through DEAE-cellulose, sephacryl S-400 HR, HW-55F and ODS-AQ column chromatography. Then 2 Polygonatum oligosaccharides could be isolated from the supernatant fluid through macroporous resin, MCI, HW-40F and ODS-AQ column chromatography.After isolation, monosaccharide composition, bonding method and other structural features of pure polysaccharide compounds are studied by monosaccharide composition analysis and 13C-NMR, 135DEPT-NMR nuclear magnetic resonance spectral analysis:1) PolysaccharideⅠis consists of four sugars, the main chain of polysaccharideⅠwas ketose which linked byβ-(1→2) bond, the glucose was linked to the main chain byαbond.2) PolysaccharideⅡis mainly constituted of mannose and galactose which linked by 1→6 bond.3) PolysaccharideⅢis pectin partly with carbethoxyl group.PolysaccharideⅠwhich mainly constituted of fructose is rarely found in Polygonatum, in addition, polysaccharideⅡand polysaccharideⅢare reported for the first time too.The structural features of pure oligosaccharide compounds are also partly understood by nuclear magnetic resonance 13C-NMR and 135DEPT-NMR spectral analysis:1) OligosaccharideⅠis consists of three sugars, glucopyranose, pyran-type fructose and pyran-type fructose, glucopyranose and pyran-type fructose are connected byβ-(1→2) bond, and furan-type fructose linked on 6-O of glucopyranosyl, and this structure of oligosaccharide is first reported in the country.2) OligosaccharideⅡis impure, it is a symmetrical structure which belongs to inositol category, the specific structural features to be studied further.