Molecular weight and helix conformation determine intestinal anti-inflammatory effects of exopolysaccharide from Schizophyllum commune

Intestinal anti-inflammatory activities of exopolysaccharide from S. commune were assessed using dextran sulfate sodium (DSS)-induced colitis in mice model. The changes of molecular weight (MW), atomic force microscope morphology, X-ray diffraction, particle size distribution, and viscosity were recorded after sonication treatment. The results indicated that the triple helical structure of exopolysaccharide was dissociated into single helical structure and random coiled structure by ultrasonication via breaking of inter- and intramolecular hydrogen bonds. The medium (936 kDa) and high MW (1437 kDa) exopolysaccharide had the mixture of triple helix and single helix conformation, while the low MW (197 kDa) exopolysaccharide exhibit random coiled conformation. The intestinal anti-inflammatory activity study showed that oral administration of medium and high MW (1437 kDa) exopolysaccharide significantly recovered DSS-induced colitis in inflamed tissues and reduced inflammation induced infiltration of macrophages. These results showed that medium (936 kDa) and high MW (1437 kDa) exopolysaccharide had intestinal anti-inflammatory activity. The intestinal anti-inflammatory activity of exopolysaccharide was related to helical structure and molecular weight.