Structural analysis of an alkali-extractable and water-soluble polysaccharide (ABP-AW1) from the fruiting bodies of Agaricus blazei Murill

An alkali-extractable and water-soluble polysaccharide (ABP-AW1) was isolated by 5% sodium hydroxide solution from the fruiting bodies of Agaricus blazei. ABP-AW1 (Mw = 50 kDa), was composed of Gal, Glc, Fuc, Ara and Man with the molar ratio of 29: 20: 6: 2: 2. According to the combination of chemical and instrumental analysis, the results indicated that ABP-AW1 had a backbone consisting of (1 → 6)-linked-β-d-galactopyranosyl, (1 → 6)-linked-β-d-glucopyranosyl and (1 → 3, 6)-linked-β-d-glucopyranosyl, which was terminated with (1→)–linked Fuc, Ara and Man residues at the O-3 position of (1 → 3, 6)-linked-β-d-glucopyranosyl in the proportion of 29: 10: 10: 6: 2:2.