Isolation, Purification And Structural Investigation Of Polysaccharides From Calvatia Gigantea

In this work, isolation, purification, structure and physicochemical properties analysis of Calvatia gigantea polysaccharides were investigated, which was academically and practicably important for opening out relationship between structure and bioactivity of Calvatia gigantea polysaccharides, making full use of this resources. The main contents and conclusions are listed as follows: Calvatia gigantea is a popular Chinese medicine of mycetes. One thousand years ago, it has been used. Calvatia gigantea polysaccharides CGP was extracted by hot water, precipitated by ethanol. Three water-soluble polysaccharides CGPⅠ-1, CGP-Ⅱand CGP-Ⅲwere isolated and purified by ionexchange chromatographies on DEAE-sepharose fast flow and Sephacryl S-300. Three fractions were shown to be homogeneous by agarose electrophoresis and Sephacryl S-300 chromatographies. The apparent average molecular weight of CGPⅠ-1, CGP-Ⅱ, and CGP-Ⅲwas estimated to be approximately 9.12×10~4 Dal, 18.6×104 Dal, and 15.6×10~4 Dal respectively. The component of three kinds of polysaccharides were identified by GC-MS: mannose, glucose and galactose were found to be in the molar radio of 1.22: 11.28: 3.92 in CGPⅠ-1; mannose,glucose and galactose were found to be in the molar radio of 1.74: 26.45: 0.36 in CGP-Ⅱand mannose,glucose and galactose were found to be in the molar radio of 1.06: 9.9: 3.29 in CGP-Ⅲ. Periodate oxidation, Smith degradation, IR and NMR were used on the structure analysis of CGP. The results revealed that CGPⅠ-1 was neutral polysaccharides which was mainly composed of pyranose and had bothβ-andα-epimer, CGP-Ⅱ, CGP-Ⅲwere acidic polysaccharides which was composed of pyranose and hadβ-epimer. The main chain of three polysaccharides both has Glc(1→3). The ratio of 1→6(1→)linkage and 1→4(1→4, 6)linkage was 7.8: 5.5 in CGPⅠ-1, 7.4: 7.9 in CGP-Ⅱand 8.4: 9.3 in CGP-Ⅲ.