The edible mushroom Albatrellus ovinus contains a α-l-fuco-α-d-galactan, α-d-glucan, a branched (1 → 6)-β-d-glucan and a branched (1 → 3)-β-d-glucan

Abstract

Albatrellus ovinus, the sheep polypore, is a large, dense mushroom being rich in cell wall material. Polysaccharides were isolated by sequential extraction, enzymatic treatment and analyzed with respect to monosaccharide composition, glycosidic linkages by methylation and GC-MS as well as NMR spectroscopy. A fucogalactan composed of an (1 → 6)-α-d-galactan backbone with single α-l-Fucp residues attached at O-2 was identified in the hot water extract obtained after treatment with a protease and size exclusion chromatography. Both the hot water extract and the hot alkali extract contained an (1 → 4)-α-d-glucan whereas β-d-glucans were mainly present in the latter. Structural analysis suggested the presence of two different β-d-glucan backbone structures; a (1 → 6)-linked β-d-glucan with single β-d-Glcp residues at O-3 and also a (1 → 3)-linked β-d-glucan with branches in O-6. In addition there were identified short (1 → 2)-linked β-d-xylan and (1 → 3)-α-d-mannan chains.

Keywords: Albatrellus ovinus; Fucogalactan; α-glucan; β-glucan.