Supernatants of Water Extraction-Ethanol Precipitation from Roots of Rosa davurica Pall. Ameliorate Ulcerative Colitis in Mice: From Gut Microbes to Metabolites.

Background

Safe treatment options for ulcerative colitis, a chronic relapsing inflammatory bowel disease, remain limited, and the bioactive fraction of Rosa davurica Pall. root associated with its protective activity against Ulcerative colitis (UC) has not been characterized.

Methods

This study evaluated the protective effects of the total root aqueous extract (WRP) and two process-defined fractions prepared by ethanol precipitation: the supernatant fraction (SRP) and crude polysaccharide precipitate fraction (PRP). These fractions were administered concurrently with Dextran sulfate sodium (DSS) during acute colitis induction in mice. Assessments included disease activity index, colon histopathology, intestinal barrier proteins, RT-qPCR analysis, fecal metabolomics, 16S rRNA sequencing, and UHPLC-MS/MS.

Results

Compared to PRP, SRP significantly alleviated DSS-induced weight loss, colon shortening, perianal bleeding, and histological injury. SRP also reduced the mRNA levels of TNF-α, IL-6, IL-1β, MPO, NF-κB, NLRP3, GSDMD, and IL-18. SRP treatment increased Claudin-1 and ZO-1 protein expression, whereas Occludin expression showed no significant change. SRP treatment was associated with shifts in fecal metabolic profiles and gut microbiota composition in DSS-treated mice, including a change in the Firmicutes/Bacteroidota ratio toward the CON group pattern. UHPLC-MS/MS profiling resulted in the tentative annotation of 68 nonredundant constituents in SRP.

Conclusions

Under the present experimental conditions, SRP demonstrated protective activity in DSS-induced acute colitis and represents a potentially important bioactive fraction of the R. davurica root aqueous extract. Its protective effects were accompanied by reduced inflammatory gene expression, partial enhancement of barrier-associated protein expression, and alterations in gut microbiota composition and fecal metabolic profiles.