Bangia fusco-purpurea polysaccharides attenuate DSS-induced colitis in mice through gut microbiota and its metabolism modulation

• Bangia fusco-purpurea polysaccharides (BFP) ameliorated the symptoms of DSS induced colitis in mice. • BFP enhanced the integrity of the intestinal barrier and mitigated the inflammation induced by DSS. • BFP modulated the composition and metabolism of the gut microbiota and reverses gut microbiota dysbiosis. • BFP effectively mitigated colitis by suppressing the expression of TLR - 4/MyD88 genes and modulating the AMPK signaling pathway. This study explored the alleviation of Bangia fusco-purpurea polysaccharides (BFP) on the symptoms of colitis in a mouse model induced by dextran sulfate sodium (DSS), with a focus on intestinal microbiota and related metabolism pathways. Findings demonstrated that treatment with BFP reduced colon shortening and body mass loss induced by DSS administration. Furthermore, BFP treatment decreased concentrations of inflammatory cytokine TNF-α and IL-22 in serum and colon tissues, and upregulated transcription of barrier-related genes, e.g., MUC2, Tff3 , and Klf4 . Moreover, BFP intervention tended to increase abundance of beneficial microbes, including Lachnoclostridium, Lacrimispora, Ruminococcus, and Akkermansia , as well as alter metabolic pathways associated with tryptophan metabolism, biosynthesis of phenylalanine, tyrosine, and tryptophan, and the citric acid cycle, suggesting its potential role in improving intestinal homeostasis. Additionally, BFP intervention was associated with activation of the AMPK signaling pathway, enhanced expression of tight junction proteins, and downregulated TLR-4/MyD88 expression. These molecular and pathway alterations may represent potential mechanisms underlying the alleviation of colitis symptoms. These observations lay a preliminary experimental groundwork for considering BFP as a potential prebiotic agent for mitigating disorders associated with colitis.