Phenolics from Dendrobium officinale Leaf Ameliorate Dextran Sulfate Sodium-Induced Chronic Colitis by Regulating Gut Microbiota and Intestinal Barrier.

The increasing incidence of colitis and the side effects of its therapeutic drugs have led to the search for compounds of natural origin, including phenolics, as new treatments for colitis. In this study, the potential mechanism of Dendrobium officinale leaf phenolics (DOP) on the relief of dextran sulfate sodium (DSS)-induced colitis was explored. The results showed that DOP treatment for 36 days reduced the symptoms of colitis caused by DSS, including reduction of the disease activity index and alleviation of colonic tissue damage. In addition, DOP downregulated the expression of key proteins of the TLR4/NF-κB signaling pathway and reduced the production of inflammatory cytokines. Furthermore, DOP could enhance the expression of tight junction proteins including ZO-1, Occludin, and Claudin-1 to restore intestinal mucosal barrier function. DOP also effectively regulates disordered intestinal flora and enhances the production of short-chain fatty acids, which is also beneficial in modulating gut internal environmental homeostasis, inhibiting inflammation, and restoring the intestinal barrier. These findings indicated that DOP can ameliorate DSS-induced chronic colitis by regulating gut microbiota, intestinal barrier, and inflammation, and it is a promising ingredient from D. officinale.