Purification and structural characterization of polysaccharides isolated from Auricularia cornea var. Li

Three main fractions, one neutral polysaccharide (ACPN-1a) and two acidic polysaccharides (ACPA-1a and ACPA-2a), were isolated from crude polysaccharides of Auricularia cornea var. Li. (ACP). The physicochemical properties and structural characteristics of these fractions were investigated using High Performance Gel Permeation Chromatography (HPGPC), High Performance Liquid Chromatography (HPLC), Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), and Nuclear Magnetic Resonance (NMR) spectra. The results showed that ACPN-1a with a higher molecular weight (∼2.18 × 10⁶ Da) was a β-(1→3)-glucan with (1→6)-linked β-Glcp residues for side chains. ACPA-1a was a heteropolysaccharide and had the backbone of (1→3)-linked β-Glcp and (1→6)-linked α-Manp and side chains with β-Xylp or β-GlcpA residues. ACPA-2a had the average molecular weight of 8.5 × 10⁵ Da and was composed of a (1→6)-linked α-Manp backbone and side chains with β-Xylp or β-GlcpA residues. The data provided useful information for further investigation on the structure-activity relationship of Auricularia cornea var. Li. polysaccharides.