Polysaccharides From Bombax ceiba Flower by Deep Eutectic Solvent Based Three-Phase Partitioning and Their Protective Effects Against DSS-Induced Colitis in Mice.

A deep eutectic solvent (DES)-based three-phase partitioning (TPP) was developed for efficient and green extraction of Bombax ceiba flower polysaccharide (BCFP). DES-1 (lauric acid and decanoic acid) was chosen as the optimal solvent. The extraction yield of BCFP reached 13.53% under optimal conditions: 5% (w/v) mass fraction of (NH4)2SO4, 25:1 (v/w) of DES-1 to crude powder, Lauric acid to decanoic acid ratio of 1:1, 10 min and 40°C. The main monosaccharides of BCFP included mannose, rhamnose, glucuronic acid (GluA), galacturonic acid (GalA), glucose, xylose, galactose, and arabinose. The obtained BCFP was characterized as acidic heteropolysaccharide with an average molecular weight of 2.15 kDa, composed of galactose, arabinose, mannose, glucose, galacturonic acid (GalA), rhamnose, xylose, and glucuronic acid (GluA). In a dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) mouse model, BCFP administration significantly attenuated DSS-induced disease activity index (DAI), body weight loss, colon shortening, spleen coefficient decreasing and histological changes. Moreover, BCFP suppressed inflammatory cytokine levels, reduced oxidative stress, and restored intestinal barrier function by enhancing mucus secretion and tight junction protein expression. This study provides an economical and environmentally friendly separation of bioactive polysaccharides from B. ceiba flower, which has potential for functional food and pharmaceutical applications in colitis management.