Purification and structural characterization of a new water-soluble neutral polysaccharide GLP-F1-1 from Ganoderma lucidum

A water-soluble neutral polysaccharide (GLP-F1-1) was isolated from the fruiting bodies of Ganoderma lucidum by DEAE Sepharose Fast Flow and Sephacryl S-500 High Resolution Chromatography. The neutral polysaccharide had an average molecular weight (Mw) of approximately 2.5 × 106 kDa. GC analysis showed that this polysaccharide was mainly composed of glucose and galactose in the molar ratio of 34:1. 1H and 13C NMR spectroscopy in combination with GC–MS technique indicated that the new polysaccharide had a backbone chain of 1,4-disubstituted-β-glucoseopyranose and 1,4,6-trisubstituted-β-glucoseopyranosyl, while the branched chains were mainly composed of 1,6-disubstituted-β-glucopyranosyl and 1,4-disubstituted-β-galactoseopyranosyl residues.