Sulfated mulberry (Morus atropurpurea Roxb.) leaf polysaccharide ameliorates dextran sodium sulfate-induced colitis via regulation of gut microbiota and intestinal barrier integrity

Ulcerative colitis (UC), a chronic inflammatory bowel disease with increasing global incidence, necessitates novel dietary interventions from sustainable sources. This study investigated a dietary polysaccharide (MLP) extracted from mulberry ( Morus atropurpurea Roxb.) leaf and its sulfated derivative (SMLP) synthesized via the sulfur trioxide-pyridine method. SMLP significantly ameliorated dextran sodium sulfate (DSS)-induced colitis in mice, attenuating weight loss, disease activity index, colon shortening, and histopathological damage compared to MLP. Mechanistically, SMLP enhanced intestinal barrier integrity (upregulated ZO-1 and MUC2 expression), increased the IL-10, decreased TNF-α and IL-1β expression, and targeted modulation of the gut microbiota-metabolite axis. SMLP specifically enriched Akkermansia muciniphila (Verrucomicrobiota) and augmented immunoregulatory short-chain fatty acids (SCFAs: acetate, propionate). Crucially, sulfation modification significantly potentiated the efficacy of MLP. This work establishes a mechanistic basis for utilizing edible plant polysaccharides, particularly through structure-guided chemical modification like sulfation, as high-value functional food ingredients against inflammation-related gastrointestinal disorders.