Fracitonation And Structural Analysis Of The Polysaccharides From Auricularia Auricala

Auricularia auricala(other names: Heicai, Ximuer and Maomuer), has been used as traditional food in China for a long time. It has immunomodulatory, reducing blood lipid, antithrombotic, anti-aging, hypoglycemic, anticoagulative and anti-tumor effects. In this articile, we studied the polysaccharides isolated from artificial cultivate Auricularia auricala..Crude water-soluble polysaccharides were isolated from the fruit bodies of Auricularia auricala by hot water extraction and precipitated by ethanol. The crude water-soluble polysaccharides (AA) were analyzed by high performance liquid chromatography (HPLC) to test the sugar compositions. It was consist of Man, GlcUA, Glc, Gal, Xyl in the ratio of 1:0.11:0.25:0.05:0.18.The polysaccharide fraction AA4HE2 was obtained from AA by successive ethanol fractionation, deproteination, acid hydrolysis and DEAE-cellulose column chromatography. AA4HE2 is white power. Homogeneity and molecular weight of AA4HE2 were determined by gel filtration and ion-exchange chromatography. The results showed that AA4HE2 was a homogeneous polysaccharide with a molecular weight of 22.8×104Da. The sugar composition analyzed by HPLC was Man, GlcUA, Glc, Gal, Xyl in the ratio of 1:0.22:0.15:0.06:0.29.The structure of AA4HE2 was elucidated by IR, GC, periodate oxidation, Smith degradation, 13C nuclear magnetic resonance (NMR), methylation analysis and GC-MS analysis. These analysis indicated that AA4HE2 has the following structure: the main linkage of AA4HE2 wasβ-(1→4)-D-linked Man, (81.86%), the side chains are composed ofα-(1→6)Glc,β-(1→3)Xyl, and (1→3),(1→4)or(1→6)α-D-GlcUA.