Structural investigation of a novel water-soluble heteropolysaccharide from the fruiting bodies of Phellinus baumii Pilát

A novel water-soluble heteropolysaccharide termed PBF2 was isolated from the fruiting bodies of Phellinus baumii Pilát using hot water extraction and purified on Sephacryl S-1000. PBF2 was shown to be composed of l-fucose, d-mannose and d-glucose. Its structural characteristics were further investigated by FT-IR spectroscopy, sugar analysis, methylation analysis and NMR spectroscopy. Based on the data obtained, PBF2 was found to be a heteropolysaccharide containing a β-(1 → 6)-d-glucopyranose backbone with a fucosyl unit on O-3 of the 3,6-di-O-substituted-d-glucosyl units and it also contained a minor (1 → 3, 6)-β-d-mannose residue and terminal glucose residues.