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.

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.

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.

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.

To promote the high-value utilization and industrial development of tartary buckwheat and to develop functional products based on tartary buckwheat bran (TBB), this study analyzed the basic composition and investigated the ameliorative effect of TBB on dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) in mice and its anti-inflammatory mechanism.

The contents of protein, fat, total dietary fiber, ash, and starch in TBB were determined. The ameliorative effect on UC induced by 3% DSS in mice was evaluated by hematoxylin and eosin staining of colon sections, enzyme-linked immunosorbent assay (ELISA), Western blotting, gas chromatography (GC), and 16S rDNA high-throughput sequencing.

Compared with the model group, TBB significantly alleviated body mass loss, reduced appetite, shortened colon length, and rectal bleeding in mice suffering from UC, mitigated colon crypt damage and goblet cell reduction, suppressed the secretion of pro-inflammatory cytokines, and reduced inflammation through inhibiting nuclear factor kappa-B (NF-κB) signaling pathway. It also restored the levels of acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and total short-chain fatty acids in the intestine while modulating the gut microbiota composition, especially enhancing the relative abundance of g__Akkermansia and g__Lactobacillus.

TBB contains a high level of dietary fiber, which can significantly alleviate UC. This finding provides a scientific basis for the high-value utilization of TBB as a functional food ingredient.