Tripartite synergy in fermented barley: probiotic-driven enhancement of bioactive metabolites restores the gut barrier and microbiota in colitis

The clinical management of Inflammatory Bowel Disease (IBD) requires novel intervention strategies, and functional fermented foods hold unique promise due to their multi-target modulatory effects. This study systematically evaluated the colitis-alleviating properties of <i>Lactiplantibacillus plantarum</i> dy-1 fermented barley (LFBE) compared with raw barley flour (RBE) and heat-inactivated strain and raw barley flour (HLFBE), emphasizing both the individual and synergistic roles of the functional matrices in LFBE. In a DSS-induced colitis model, the three interventions exhibited a clear gradient of efficacy (LFBE > HLFBE > RBE), with the LFBE group showing the most pronounced therapeutic benefits, including minimal body weight loss (14.12% <i>vs.</i> 15.56% in HLFBE, 17.47% in RBE and 24.86% in Model) and a significantly lower disease activity index (2.37 <i>vs.</i> 2.59 in HLFBE, 2.96 in RBE and 3.29 in Model). Notably, LFBE uniquely enriched phenolic compounds and carbohydrates, reducing pro-inflammatory cytokine levels. Moreover, its probiotic components activated <i>KLF4</i>/<i>ATOH1</i>-mediated goblet cell differentiation, thereby enhancing mucin production. Gut microbiota analysis further revealed that LFBE promoted the proliferation of <i>Akkermansia</i> (+61.93%) and <i>Lachnospiraceae</i> (+130.85%) while inhibiting the colonization of <i>Escherichia</i>-<i>Shigella</i> (-69.84%). These findings highlight the synergistic contributions of probiotic compounds, fermentation-enhanced bioactive compounds, and the prebiotic barley matrix in LFBE. Collectively, this work provides a theoretical foundation and innovative avenues for developing precision fermentation-based, targeted interventions for IBD management.