Rhamnogalacturonan-I-rich polysaccharide from Malus prunifolia attenuates dextran sulfate sodium-induced colitis and improves the gut microenvironment.

In our previous study, we identified and characterized a rhamnogalacturonan-I (RG-I)-rich polysaccharide (MP-PE-I) derived from Malus prunifolia (MP), which exhibited notable immunomodulatory activity in IL-1β-stimulated intestinal epithelial cells. This study assessed the protective potential of MP-PE-I in a murine model of intestinal inflammation induced by dextran sulfate sodium (DSS). MP-PE-I was administered orally for three consecutive weeks, during which it was well tolerated and markedly alleviated colitis-related clinical symptoms and pathological features, including colon shortening and splenomegaly. MP-PE-I treatment effectively modulated the DSS-triggered dysregulation of inflammatory cytokines and chemokines, while restoring gene expression related to tight and adherens junctions. Histological evaluation confirmed that MP-PE-I mitigated DSS-induced structural damage in colonic tissue, including preservation of mucin-producing goblet cells. These protective effects were associated with alterations in MAPK- and NF-κB-related signaling pathways. Furthermore, MP-PE-I treatment significantly restored the DSS-induced reduction in short-chain fatty acid levels, accompanied by overall improvements in the gut microenvironment. Collectively, these findings demonstrate the anti-colitic potential of MP-derived RG-I-rich polysaccharides and support their further development as functional agents for intestinal health maintenance.