Polysaccharides of basidiomycetes. Alkali-soluble polysaccharides from the mycelium of white rot fungus Ganoderma lucidum (Curt.: Fr.) P. Karst

摘要

Two polysaccharides were isolated from submergedly cultured mycelium of the basidiomycete Ganoderma lucidum by extraction with alkali followed by fractionation with Fehling reagent. The polysaccharides were shown to be a linear (1[arrow right]3)-α-D-glucan and a highly branched xylomannan containing a backbone built up of (1[arrow right]3)-linked α-D-mannopyranose residues, the majority of which are substituted at O-4 by single β-D-xylopyranose residues or by disaccharide fragments β-D-Manp-(1[arrow right]3)-β-D-Xylp-(1[arrow right]. Polysaccharide structures were elucidated by NMR spectroscopy in combination with methylation analysis and periodate oxidation. An interesting feature of the xylomannan is the simultaneous presence of α-D-mannopyranose and β-D-mannopyranose residues, the first forming the backbone, and the second being the non-reducing terminal units of disaccharide side chains. [PUBLICATION ABSTRACT]