Scutellaria baicalensis Georgi polysaccharide ameliorates DSS-induced ulcerative colitis by improving intestinal barrier function and modulating gut microbiota

The aim of this study was to investigate the effect of a polysaccharide from Scutellaria baicalensis Georgi on UC. Gut microbiota dysbiosis is a worldwide problem associating with ulcerative colitis. One homogeneous polysaccharide, named SP2-1, was isolated from Scutellaria baicalensis Georgi. SP2-1 comprised mannose, ribose, rhamnose, glucuronic acid, glucose, xylose, arabinose, fucose in the molar ratio of 5.06:21.24:1.00:20.25:3.49:50.90:228.77:2.40, with Mw of 3.72 × 106 Da. SP2-1 treatment attenuated body weight loss, reduced DAI, ameliorated colonic pathological damage, and decreased MPO activity of UC mice induced by DSS. SP2-1 also suppressed the levels of proinflammatory cytokines. Additionally, the intestinal barrier was repaired due to the up-regulated expressions of ZO-1, Occludin and Claudin-5. SP2-1 remarkably enhanced the levels of acetic acid, propionic acid, and butyric acid in DSS-treated mice. Furthermore, as compared with model group, the abundance of Firmicutes, Bifidobacterium, Lactobacillus, and Roseburia were significantly increased with SP2-1 treatment. And SP2-1 could significantly inhibit the levels of Bacteroides, Proteobacteria and Staphylococcus. In conclusion, SP2-1 might serve as a novel drug candidate against UC.