| A water soluble polysaccharide has been isolated from the stem of the wild Cistanche salsa G.Beck. The crude polysaccharide was deproteinized by Sevage method, freezed-melted repeatedly, and fractionated by hydrogen peroxide solution and ultrafiltration, giving a polysaccharide fractions termed SPA. Its homogeneity was proved by HPLC etc. GC show it consists of Rha, Ara, Man, Gal and Glc with the molarity rate of 1:1.83:3.06:4.56:14.75 in turn. These indicated that SPA was a kind of neutral heteropolysaccharide, as well as it consisted mainly of glucose and some galactose, Ala, Rha and Man. Average molecular weight of SPA was around 0.76×104.In the structure analysis of SPA,13C-NMR, partial hydrolysis with acid, periodate oxidation, Smith degradation, I.R. ,G.C. and methylation etc. were the principal methods used. After acetylation, the methylated productions were analyzed by G.C.-M.S.The results revealed that SPA was a kind of low branched structure. The main chain was composed of (1 -- 6)-linked-Glc, and (1--6)-linked-Glc residues were substituted at O-3. On average, there are 1 branche among 7 main chain residues; A and Bwere side chains, they are composed of (1 --4)-linked-Gal, (1 — 4)linked-Man, (1 — 3)-linked-Gal and (1 — 2)-linked-Rha residues. So itd possible repeated unit was:The side chains were:... |
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