Abstract: Objective: To further explore and develop tartary buckwheat (Fagopyrum tataricum), a specialty agricultural product of Liangshan, Sichuan province, this study investigated the effect and mechanism of action of tartary buckwheat seedling powder (TBSP) on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) and the gut microbiota in mice. Methods: A mouse model of UC was established using 3% DSS. The mice received TBSP via gavage at doses of 100 or 400 mg/kg. Changes in body mass, disease activity index (DAI) score, organ indices, colon length, histopathological damage, colonic inflammatory cytokine levels, protein expression of nuclear factor kappa B (NF-κB) and inhibitor of nuclear factor kappa B alpha (IκBα), alterations in the gut microbiota, and short-chain fatty acid (SCFA) contents were evaluated. Results: TBSP significantly ameliorated pathological states in UC mice, including body mass loss, increased DAI score, colon shortening, intestinal barrier damage, elevated inflammatory cytokine levels, and overactivation of the NF-κB signaling pathway, in a dose-response manner. TBSP modulated the structure of the gut microbiota in UC mice. At the phylum level, it decreased the relative abundances of Proteobacteria and Desulfobacterota while increasing that of Verrucomicrobiota. At the genus level, it increased the relative abundances of barrier repair-associated genera such as Akkermansia and Lactobacillus. Conclusion: TBSP alleviated colitis symptoms by regulating the gut microbiota, reducing inflammatory cytokine levels, and repairing the colonic mucosal barrier in UC mice. Therefore, TBSP is a promising functional food resource.

Key words: tartary buckwheat seedling powder; ulcerative colitis; inflammatory cytokines; nuclear factor κB signaling pathway; gut microbiota; correlation analysis