Compositional analysis and physicochemical characterization of a purified tremella fuciformis polysaccharide-rich fraction and its intestinal barrier- and microbiota-related effects in DSS-induced colitis.

Tremella fuciformis is a widely consumed edible fungus and a source of structurally diverse polysaccharides, but the intestinal biofunctionality of a purified Tremella polysaccharide-rich fraction remains insufficiently defined. In this study, a purified T. fuciformis polysaccharide-rich fraction (TPS) was obtained by hot-water extraction, ethanol precipitation, anion-exchange chromatography, and gel filtration. TPS was characterized using carbohydrate/protein analysis, gel permeation chromatography (GPC), monosaccharide composition analysis, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), 1H NMR, dynamic light scattering (DLS), zeta-potential analysis, and thermogravimetric analysis. TPS contained 96.13% total carbohydrate and 5.61% protein and showed features of a mannose-rich acidic heteropolysaccharide, including mainly amorphous organization, aggregated morphology, mixed anomeric proton signals, hydrated colloidal aggregates, negative surface charge, and staged thermal degradation behavior. Its intestinal effects were evaluated in a dextran sulfate sodium (DSS)-induced colitis mouse model. Oral TPS administration alleviated DSS-induced colonic injury, as indicated by improved disease activity and histological features, preservation of ZO-1 and Occludin expression, and reduced colonic TNF-α, IL-1β, and IL-6 levels. TPS was also associated with partial changes in DSS-disrupted gut microbiota profiles and with lower downstream inflammatory protein readouts in the TLR4/MyD88/NF-κB pathway. Molecular docking of TPS-associated monosaccharides was retained only as supplementary exploratory in silico context and was not interpreted as evidence of intact TPS binding, validated receptor engagement, or direct in vivo TLR4 targeting. Overall, this study connects fraction-level compositional and physicochemical characterization of a food-derived Tremella polysaccharide-rich fraction with measurable intestinal barrier-, inflammation-, and microbiota-related responses, providing a basis for future structure-function studies of edible fungal polysaccharides in intestinal health.