Structural characterization of polysaccharide from an edible fungus Dictyophora indusiata and the remodel function of gut microbiota in inflammatory mice.

Dictyophora indusiata is an edible fungus, which is known as bamboo fungus. D. indusiata polysaccharide is considered as the most important bioactive component. The aim of this study was to investigate the structure of a polysaccharide fraction from D. indusiata and the effects of D. indusiata polysaccharide on gut microbiota and metabolites in inflammatory mice. Here, the DIP1, a polysaccharide fraction from D. indusiata, was obtained by isolation and purification using Cellulose DE-52 column and Sephadex G-200 gel column. The results showed that DIP1 is a heteropolysaccharide consisting of glucose, mannose, galactose and xylose in the ratio of 55.2 %, 28.6 %, 10.3 % and 5.9 %, which mainly linked by →3)-Glcp-(1 → glycosidic bonds. In addition, D. indusiata polysaccharide restored the colonic length reduction, modulated the secretion of cytokine and mitigated histological damage. It is remarkable that D. indusiata polysaccharide enhanced the abundance of beneficial bacteria Blautia and Roseburia, and increased the levels of short-chain fatty acids including acetic acid and propionic acid. Our findings indicated that D. indusiata polysaccharide remodeled gut microbiota and enhanced short-chain fatty acids levels to alleviate the inflammation.