Structural characterization of a branched (1 → 6)-α-mannan and β-glucans isolated from the fruiting bodies of Cantharellus cibarius

• The chanterelle cell wall contains an (1 → 6)-α-mannan, (1 → 6)- and (1 → 3)-β-glucans.
• The α-mannan is a water soluble polysaccharide extracted in boiling water.
• The release of β-glucans requires treatment with hot alkali solution.

A comprehensive characterization of polysaccharides from the chanterelle was performed. Experiments included both linkage analysis by methylation and GC–MS, monosaccharide composition analysis by methanolysis, SEC-MALLS and several NMR experiments including COSY, HSQC, TOCSY, HSQC-TOCSY, NOESY, and HMBC. A 671 kDa (1 → 6)-linked α-d-mannan with single and short (1 → 2)-linked side chains (WCcF1b) was isolated from the hot water extract, after protease treatment and fractionation by size exclusion chromatography. The hot 1 M NaOH extract contained two types of β-glucan; a water soluble (1 → 6)-linked β-d-glucan with single and short (1 → 3)-linked β-glucan side chains (ACcSw) and a less branched (1 → 3)-linked β-d-glucan (ACcIw/ACcId), proposed to contain short side chains in O-4. Chemical shifts assignments of the α-mannan and β-glucan are presented as well as chemical shift values obtained from a (1 → 6)/(1 → 3)-β-d-glucan derived from Saccharomyces cerevisiae which was used as reference.