Structural characterization and hydroxyl radicals scavenging capacity of a polysaccharide from the fruiting bodies of Auricularia polytricha

Abstract

Abstract One low molecular-weight polysaccharide (APP) of 2.8 × 10 4 Da was isolated from the fruiting body of Auricularia polytricha . Partial hydrolysis with acid, periodate oxidation–Smith degradation, acetylation, methylation analysis and NMR spectroscopy ( 1 H, 13 C) were conducted to elucidate its structure and the repeating unit of APP was established as: the backbone was composed of (1 → 3)-linked-β- d -mannopyranosyl, (1 → 3)-linked-β- d -galactopyranosyl and (1 → 3,6)-linked-β- d -mannopyranosyl residues in the ratio of 3:2:1, and terminated with one single terminal (1→)-β- d -glucopyranosyl at the O -6 position of (1 → 3,6)-linked-β- d -mannopyranosyl along the main chain. Preliminary antioxidant activity test in vitro showed APP could potentialize scavenging effect on hydroxyl radicals in a dose dependent manner.