Alleviating effect of Gardenia Fructus polysaccharide and its enzymatic hydrolysate on DSS-induced colitis.

Inflammatory bowel disease (IBD) is closely associated with gut microbiota dysbiosis and systemic manifestations. Pectic polysaccharides have recently become a research hotspot because of their therapeutic effects on IBD and safety. Previous in vitro studies indicated that polysaccharide from Gardenia Fructus (GFP) and its enzymatic hydrolysate (GFPE) modulated gut microbiota composition, but their in vivo effect and underlying mechanisms against colitis remained unknown. Therefore, this study investigated the effects of GFP and GFPE on DSS-induced colitis in mice. The results indicated that oral administration of GFP and GFPE significantly reduced the disease activity index and restored the colon length (p < 0.05). In addition, GFP and GFPE increased the number of goblet cells, decreased the levels of pro-inflammatory cytokines, up-regulated the expression of tight junction proteins, enhanced intestinal immunity, and mitigated oxidative stress. Moreover, GFP and GFPE significantly increased the relative abundance of beneficial genera (Akkermansia, Lachnospiraceae, etc.) and decreased the relative abundance of harmful or colitis-associated genera such as Escherichia-Shigella, etc. (p < 0.05), as well as regulated short-chain fatty acid production. Collectively, these findings suggested the protective effects of GFP and GFPE against colitis, providing a scientific basis for their development as novel functional foods.