Oat Avenanthramide-C Alleviates DSS-Induced Colitis Through Regulating Intestinal Immune Activity and Gut Microbiota in Mice.

Oat avenanthramide-C (AVN-C) exhibits notable anti-inflammatory and antioxidant properties, while its potential effects on inflammatory bowel disease (IBD) remain unclear. This study aimed to investigate the impact of AVN-C on dextran sulfate sodium (DSS)-induced colitis and explore the underlying mechanisms. Male C57BL/6J mice were treated with AVN-C (5 and 10 mg/kg BW) for 1 week prior to receiving 2.5% DSS in drinking water for 7 days to induce colitis. AVN-C treatment continued during the DSS period. The results showed that AVN-C ameliorated DSS-induced colitis symptoms and intestinal barrier dysfunction. AVN-C treatment also reduced neutrophil infiltration and prevented neutrophil extracellular traps (NETs) formation. Moreover, AVN-C elevated the relative abundance of Firmicutes and Akkermansia, while reducing Proteobacteria and Escherichia-Shigella, thereby shifting the gut microbial composition toward a more favorable state associated with reduced inflammation. Meanwhile, AVN-C consumption significantly enhanced intestinal immune activity and maintained gut microbiota balance by modulating primary bile acid biosynthesis through the FXR-SHP-NF-κB signaling pathway. Collectively, AVN-C exhibited a protective effect against DSS-induced colitis by modulating neutrophil function, gut microbiota, and bile acid metabolism. These findings highlight the potential of oat AVN-C as a therapeutic strategy for IBD, offering valuable insights into gastrointestinal health.