Structural characterization and protective effect against oxidative stress of Volvariella volvacea polysaccharide

In the present study, a homogeneous polysaccharide (HVP-2) was isolated and purified from (Chinese mushroom) Volvariella volvacea. The structural characteristics and protective effect of HVP-2 were investigated. The results showed that HVP-2 was composed of mannose, glucose, galactose and arabinose in a molar ratio (mol%) of 59.58: 19.63: 18.28: 2.51. The HVP-2 backbone structure was consisted of →4)-β-D-Galp-(1 → 4)-β-D-Manp-(1 → 4,6)-β-D-Manp-(1 → 3)-β-D-Glcp-(1 →. The branched structure of α-L-Araf-(1 →, →6)-α-D-Glcp-(1 → and → 6)-β-D-Manp-(1 → was attached to the main chain via the O-4 position of →4,6)-β-D-Manp-(1→. Antioxidant activity experiments demonstrated that HVP-2 improved cell viability by inhibiting reactive oxygen species (ROS) production, up-regulating the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). The western blotting results showed that HVP-2 activated the Nrf2/HO-1 signaling pathway, up-regulated the expression of heme oxygenase 1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1) expression to prevent hydrogen peroxide-induced oxidative damage. These results suggested that HVP-2 may be a natural antioxidant.