Isolation,Purification and Structural Characteristics of Water Soluble Polysaccharide PMEP-1 from Morchella esculenta (L.) Pers.

The polysaccharide PMEP-1 was isolated from Morchella esculenta (L.) Pers. through hot-water extraction and subjected to Sevag deprotein,dialysis,ethanol precipitation,DEAE-52 cellulose ion-exchange column chromatographic analysis and Sephadex G-100 column chromatographic analysis. This polysaccharide was found to be highly homogeneous with a relative molecular mass of 43600 and a specific rotation of +257.0 (C = 0.001,H2O) and the yield reached 1.58%. The chemical structure of PMEP-1 was analyzed by chemical methods (including partial hydrolysis with acid,methylation reaction,periodate oxidation,and Smith degradation) and instrument analysis methods (using IR,GC-MS,1H-NMR,and 13C-NMR). The polysaccharide PMEP-1 was found to be composed of Ara,Man,Glc and Gal with a molar ratio of 1:2.37:4.79:3.09 and be a complex heteropolysaccharide with highly ramified structure,whose main chain was formed by a mixing linkage of α-1,4-glucose,α-1,6-galactose,α-1,2-mannose and α-1,5-arabose and whose side chains were attached at α-1,2,6-mannose,α-1,4,6-glucose and α-1,2,6-galactose.