Procuring the polysaccharides with anti-inflammatory bioactivity from Russula vinosa Lindblad by citric acid extraction

Russula vinosa Lindblad is a wildly edible fungus that has been used as the health food due to its high content of bioactive constituents. This study investigated the anti-inflammatory bioactivity of two kinds of low-molecular-weight polysaccharides (CA-S and CA-L) extracted by citric acid (CA) from Russula vinosa Lindblad. The structure of CA-S and CA-L were identified using different characterization techniques. Structural characterization revealed that both CA-S and CA-L possessed a similar structure for the backbone but differed in the substitution sites and residues. CA-S and CA-L demonstrated the ability to ameliorate the damage of intestinal tissue in dextran sulfate sodium (DSS)-induced ulcerative colitis mice in vivo, the DAI values of CA-S and CA-L fed mice decreased by 36.84% and 31.58% respectively. This might be attributed to CA-S's higher Mw, increased content of OH groups, and an enriched mannose fraction. Immuno-analysis revealed that CA-S better reduced inflammation and oxidative-state-related stress by scavenging the endogenous reactive oxygen species through the activation of Nrf2 and suppression of the NFκB signaling pathways.