Journal Article
Structure and antitumor activities of the water-soluble polysaccharides from Ganoderma tsugae mycelium [2005]
Peng, Y.; Zhang, L.; Zeng, F.; Kennedy, J.F.;
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Six water-soluble polysaccharides coded as GTM1 to GTM6 were extracted sequentially from the mycelium of Ganoderma tsugae with 0.2 M sodium phosphate buffer solution at 25, 40, and 80 degrees C, water at 120 degrees C, 0.5 M sodium hydroxide at 25 and 65 degrees C. The chemical structures were determined by using IR, EA, GC and 13C NMR. The weight-average molecular mass (M(w)) was characterized by size exclusion chromatography combined with laser light scattering (SEC-LLS). The results indicated that the samples GTM1 and GTM2 were heteropolysaccharide-protein complexes with the protein content of 13.5 and 20.1%, and apparent-mean M(w) of 62.8 x 10(4), 81.8 x 10(4), respectively. GTM3 and GTM4 contained (1 leads to 3)-beta-D-glucans and (1 leads to 4)-alpha-D-glucans, while GTM5 and GTM6 were mainly a (1 leads to 6)-branched (1 leads to 3)-beta-D-glucan. Two peaks were found in the SEC patterns of the four samples GTM1 to GTM4, representing fractions 1 composed of branched (1 leads to 4)-alpha-D-glucan with high M(w) and fraction 2 composed of galactose, glucose and mannose with relatively low M(w). With the progress of isolation, the content of fraction 2 decreased from 90.2 to 57.1%, accompanying with enhancing antitumor activity. The polysaccharides GTM1, GTM2 and GTM3 had significantly higher antitumor activity against solid tumor Sarcoma 180 with the inhibition ratio beyond 50%. The results suggested that the effects of the moderate content of galactos
e and bound protein, as well as relatively lower M(w), on the improvement of antitumor activities of polysaccharides could not be negligible.
