Structure Investigation Of Water Soluble Polysaccharide GLP₂ And GLP₃ From Spores Of Ganoderma Lucidum

The spores of Ganoderma lucidum were previously defatted with petroleum ether andgot rid of monosaccharides and oligosaccharides with 70% methanol. Then the residue wasdecocted with hot water. The water soluble crude polysaccharide GLP was extracted from theresulting aqueous mixture by the method of ethanol precipitation. G.C. analysis illustrated thatGLP consisted of Glc and Gal in the molar ratio of 14.9:1.00.GLP was purified by freeze thawing and Sepharose CL-6B gel filitration. Two fractionswere obtained: GLP2 and GLP3. The Sepharose CL-6B gel filitration,DEAE-Sephadex A-25and HPLC analysis indicated that GLP2 and GLP3 were both homogeneous polysaccharideson molecular weight and polarity because of their single strait symmetry apex. Their molecularweight is 5.37×104 and 1.41×104 respectively. GLP2 and GLP3 are both composed of Glc andGal. The molar ratio is 12.31:1.00 and 4.46:1.00 respectively.By means of partial hydrolysis with acid, periodate oxidation, Smith degradation,methylation, IR, GC, GC-MS and 13C-NMR, the structures of GLP2 and GLP3 were identified.GLP2 is mainly made up of β configuration glycosidic bond and is a lowly branchedmolecule with basic structure composed of (1→3)-linked-Glc and (1→6)-linked-Glc residuesin the main chain. Some of (1→6)-linked-Glc residues are substituted at 3-O or 4-O. Onaverage, there are 2 branches among 10 units. The side chain is composed of(1→4)-linked-Gal. The nonreduced end is Glc.GLP3 is mainly made up of β configuration glycosidic bond and is a lowly branchedmolecule also. The main chain is made up of (1→3)-linked-Glc and(1→6)-linked-Gal.Some of (1→3)-linked-Glc residues are substituted at 6-O and some of (1→6)-linked-Galare substituted at 2-O and 4-O. On average, there are 2 branches among 10 units. The(1→4)-linked-Gal and (1→6)-linked-Glc are on the side chain. The nonreduced end is Glc.