Structural characterization and protective effects against DSS-induced injury of degraded polysaccharides from Sporisorium reilianum

Sporisorium reilianum has been commonly used for its high nutritional value, with its main active ingredient being polysaccharides. However, the high molecular weight (Mw) of polysaccharides limits their functionality, and reducing their Mw enhances activity. To improve the bioactivity of polysaccharides, this study degraded high-molecular-weight polysaccharides (SRPS) into low-molecular-weight polysaccharides (LSRP). Our results showed that LSRP was a neutral polysaccharide. The main chain was primarily composed of →4)-α-D-Glcp-(1→, while branched chains were suggested to consist of α-D-Glcp-(1 → 3) and α-D-Glcp-(1 → 6), which were likely attached to the C6 and C3 positions of the main chain. Subsequently, LSRP was identified a moderately absorbable compound that absorbed into Caco-2 cells via endocytosis, remaining in the small intestine for an extended period. Further studies confirmed LSRP stably bound with the core target BCL-2 and restored injury induced by dextran sulfate sodium (DSS), enhanced the expression of tight junction proteins, thereby improving intestinal barrier function. Overall, our research identified a novel low-molecular-weight polysaccharide and elucidated its structure, absorption characteristics, and protective effects on DSS-induced injury, providing new insights into the potential of LSRP to alleviate colitis.