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-1 a 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-la with a higher molecular weight (similar to 2.18 x 10(6) Da) was a beta-(1 -> 3)-glucan with (1 -> 6)-linked beta-Glcp residues for side chains. ACPA-1a was a heteropolysaccharide and had the backbone of (1 -> 3)linked beta-Glcp and (1 -> 6)-linked alpha-Manp and side chains with beta-Xylp or beta-GlcpA residues. ACPA-2a had the average molecular weight of 8.5 x 10(5) Da and was composed of a (1 -> 6)-linked alpha-Manp backbone and side chains with beta-Xylp or beta-GlcpA residues. The data provided useful information for further investigation on the structure-activity relationship of Auricularia cornea var. Li. polysaccharides.