Elm Ear Water-soluble Polysaccharide Structure

The water solube crude polysaccharide had been exacted by 6%Carbamide(GI) from Gloeostereum.Insarnatum.The crude polysaccharide GI was analysed by G.C.It is consist of Xyl,Man,Gal,Glc.The molar ratio is 5.2:1.0:5.5:2.8.GI had been fractionated by ethanol and purified by Sepharose CL-6B gel filitration.Three fractions were obtained: GI1, GI2 and GI3.The structure of GI3 was determined in this experiment. GI3 is brown power.G.C analysis indicates that GL3 is composed of Xyl,Gal,Glc.The molar ratio is 1.0:18.0:5.0.After being checked by Sephadex G-75 column chromatogram, DEAE-Sephadex A-25 chromatogram and HPLC,it was proved to be homogeneous polysaccharide on molecular weight and polarity as well.The totle sugar content of GI3 is 95.5%. Its average molecular weight is 18kd by means of HPLC.Through IR,G.C,partial hydrolysis with acid, periodate oxidation,Smith degradation, 13C-NMR ,methylation and G.C-MS analysis.They reveal that GI3 is a kind of lowly branched structure.There are major a -configuration and minor # -configuration.The main chain is mainly made up of Gal,Glc, There are (1 -6) Gal and (1-6) Glc, (1- 3) Gal and (1-3) Glc resudues are substituted at 6-0.On average,there are 2 branches among 10 main chain residues.The side chains are composed of (I-3) Gal and (1-3 ) Glc .The nonreduced end is composed of Xyl,Man and Glc.