A novel glucomannan from Bletilla striata ameliorates colitis: Restores intestinal barrier, alleviates inflammation, and modulates the gut flora

Background Ulcerative colitis (UC) involves intestinal barrier dysfunction, immune dysregulation, and microbiota imbalance. Bletilla striata polysaccharide (BSP) shows anti-inflammatory potential, but its UC mechanisms remain unclear. Purpose To purify Bletilla striata polysaccharide (BSP-1), characterize its structure, and elucidate its multi-target UC therapeutic mechanisms. Methods This study purified a novel structure of neutral glucomannan with a small amount of acetylation (BSP-1). Together with tight junction protein analysis, oxidative stress markers, 16S rRNA sequencing, cytokine quantification, and molecular ecological network examination, the team used a UC mouse model created using dextran sodium sulfate (DSS). Results BSP-1 alleviated colitis by inhibiting TLR4/MyD88/NF-κB signaling (elevating IL-10; lowering IL-6, TNF-α, and IL-1β) and restoring integrity of the intestinal barrier via upregulating Occludin, ZO-1, MUC2, and Claudin-1. It reduced oxidative stress (lower MDA; higher SOD) and modulated gut microbiota (enriched Lactobacillus , suppressed Escherichia - Shigella ). Molecular ecological network analysis showed that BSP-1 restored microbial community stability by enhancing bacterial competition. Conclusion BSP-1 exerts integrated anti-inflammatory, barrier-repairing, and microbiota-regulating effects, highlighting its potential as a multi-target UC therapy and intestinal microecological regulator.