Structure characterization of the mannofucogalactan isolated from fruit bodies of Quinine conk Fomitopsis officinalis

The mannofucogalactan as a major component of water extract was obtained from fruit bodies of Fomitopsis officinalis by extraction with boiling water followed by deproteination, decoloration, and purification using anion-exchange chromatography and size exclusion chromatography. Its structure was characterized using the data of monosaccharide composition, methylation analysis, one- and two-dimensional NMR spectroscopy. The studied polysaccharide was a branched mannofucogalactan with a backbone composed of partially 3-O-methylated 1,6-O-linked α- D -galactopyranosyl residues. Almost every second residue in the backbone was substituted at O-2 by 3-O-α- D -mannopyranosyl-α- L -fucopyranosyl and β- D -galactopyranosyl residues. The non-reducing terminal α- L -fucopyranosyl units, which were identified by GC–MS analyses, appeared to be the part of mannofucogalactan side chains also.