Polysaccharides from Rosa roxburghii Tratt fruit: The effect of extraction solvent on their chemical structure, bioactivities, in vitro simulated digestion and fecal fermentation characteristics

Polysaccharides extracted from Rosa roxburghii Tratt fruit (RTFPs) using hot water, 0.9 % NaCl, 5 % NaOH/0.05 % NaBH 4 or citric acid (pH 3.0) were systematically compared for their structure, antioxidant and hypoglycemic capacities, simulated gastrointestinal stability, and human-fecal fermentation behavior. Citric-acid extraction yielded a low-molecular-weight, uronic-acid-rich fraction that exhibited the strongest DPPH, ABTS, hydroxyl and superoxide radical-scavenging activities and the lowest IC 50 values against α-glucosidase and α-amylase. During in-vitro digestion RTFPs remained largely intact, yet fermentation of the citric fraction selectively enriched Bacteroides , Phascolarctobacterium and Dialister , enhanced acetate, propionate and butyrate production and markedly reduced pH. Structure-function correlation analyses highlighted uronic acid content and molecular weight as key drivers of bioactivity. These findings demonstrate that solvent engineering tailors RTFPs architecture and orchestrates distinct metabolic benefits, positioning citric-acid-derived RTFPs as a promising antioxidant, antidiabetic and prebiotic ingredient for functional foods. The study guides formulation for diabetes management and gut health.