Structural characterization and protective effect on PC12 cells against HO-induced oxidative damage of a polysaccharide extracted from mycelia of Lactarius deliciosus Gray.

The crude polysaccharide LDP was extracted from mycelia of Lactarius deliciosus Gray and then purified by DEAE-52 cellulose and Sephadex G-200 to obtain a novel polysaccharide named LDP-CP. LDP-CP was mainly composed of mannose, glucose and galactose with an average molecular weight of 2.33 × 10 kDa. The structure of LDP-CP was determined by FT-IR, methylation and NMR analysis, and the results showed that the sugar linkage units of LDP-CP were composed of (1 → 3)-linked β-D-Manp, (1 → 2,4)-linked α-D-Manp, (1→)-linked α-D-Manp, (1 → 4)-linked β-D-Glcp, (1 → 2)-linked β-D-Manp, (1 → 4,6)-linked α-D-Manp, (1 → 4)-linked α-D-Galp, (1 → 2,3)-linked α-D-Glcp and (1→)-linked α-D-Glcf. The protective effects of LDP and LDP-CP on PC12 cells against HO-induced oxidative injury were exhibited by enhancing cell viability and morphological protection. The improvement to the level of LDH, SOD and GSH further indicated that LDP and LDP-CP had ability to alleviate HO-induced oxidative damage on PC12 cells. The polysaccharides in Lactarius deliciosus Gray mycelia exhibited the great advantages in the management of oxidative toxicity, which indicated that the polysaccharides can be further developed in application of natural functional food source.