Inhibition of dextran sodium sulfate-induced colitis in mice by baker’s yeast polysaccharides

Most of the reported yeast polysaccharides are a mixture of chitin, β-glucan and mannoprotein, leading to different biological activities. Herein, we report the structures and the anti-inflammation of the purified baker's yeast polysaccharides (BBG1-BBG4). Experimental data indicated that BBG1 was a highly branched β-(1,6)-glucan linked to mannoprotein; BBG2 was a linear β-(1,3)-glucan; BBG3 and BBG4 were mixtures of a β-(1,6)-branched β-(1,3)-glucan and a linear β-(1,3)-glucan. Of these, BBG1 exhibited stronger inhibition of pro-inflammatory mediators of NO/iNOS, IL-6, IL-1β, etc. at protein and/or mRNA levels in LPS-stimulated RAW264.7 cells through inhibiting MAPK signalling pathways. Orally administered BBG1 and BBG2 significantly decreased the pro-inflammatory mediators of IL-6, iNOS and IL-1β at protein and/or mRNA levels, as well as colonic mucosal damage and macrophages infiltration in DSS-induced colitis mice. All these findings suggest that yeast polysaccharides have potentials as anti-inflammatory drugs or adjuvants in the intestinal inflammation therapy.