A water-eluted polysaccharide fraction from Chinese yam alleviates DSS-induced colitis in association with gut microbiota remodeling and attenuation of ferroptosis-related alterations

Dietary polysaccharides interact with the gut microbiota, but their relationship with ferroptosis-related alterations during colitis remains incompletely understood. This study investigated a water-eluted polysaccharide fraction from Chinese yam ( Dioscorea polystachya Turcz.; PDO) in dextran sodium sulfate (DSS)-induced colitis and examined the transferability of its associated protective phenotype using fecal microbiota transplantation (FMT). PDO-treated mice showed lower disease activity and histopathological injury, decreased colonic iron and malondialdehyde. These changes were accompanied by increased GPX4 and SLC7A11 immunofluorescence signals, decreased ferritin light chain and transferrin receptor 1 signals, and fewer mitochondrial ultrastructural abnormalities. PDO also increased fecal concentrations of acetate, propionate, and butyrate, preserved epithelial junction-protein expression, and altered gut microbial composition, including the relative abundance of Lactobacillus. Fecal transfer from PDO-treated donors reproduced several protective features in recipient mice, including lower colitis severity, changes in redox and iron-handling markers, higher fecal SCFA concentrations, and preservation of junction proteins. These findings associate PDO administration with microbiota remodeling and attenuation of ferroptosis-related biochemical and molecular alterations. They do not establish direct inhibition of ferroptotic cell death, SCFA-mediated causality, or restoration of functional intestinal permeability. PDO warrants further characterization and mechanistic evaluation as a food-derived polysaccharide fraction.