Astragaloside IV from Astragalus membranaceus Fisch. ex Bunge Mitigates DSS-Induced Colitis via Anti-Inflammatory and Antioxidant Modulation of the Gut–Liver–Brain Axis

BACKGROUND: Fisch. ex Bunge has long been used in East Asian medicine for gastrointestinal disorders and immune modulation. Astragaloside IV (AS-IV), a major bioactive saponin from its roots, exhibits potent anti-inflammatory and antioxidant activities, yet its protective effects against inflammatory bowel disease (IBD)-associated multi-organ damage via the gut-liver-brain axis remain unclear. METHODS: Experimental colitis was induced in C57BL/6N mice by administering 5% dextran sulfate sodium (DSS) in drinking water for seven days. AS-IV (100 mg/kg/day) was orally administered during DSS exposure. Disease severity was evaluated using body weight, colon length, disease activity index, and histopathology. Inflammatory cytokines and oxidative stress markers were measured using ELISA, and NF-κB and MAPK signaling were analyzed through Western blotting and immunohistochemistry in colonic, hepatic, and brain tissues. RESULTS: AS-IV significantly alleviated DSS-induced weight loss, disease activity, and colon shortening, while improving intestinal histopathological damage. AS-IV also reduced systemic pro-inflammatory cytokine levels and oxidative stress. Mechanistically, AS-IV was associated with a reduced expression of phosphorylated NF-κB and MAPK proteins, including p-NF-κB, p-IκBα, p-ERK, p-JNK, and p-p38, across the colon, liver, and brain. CONCLUSIONS: AS-IV attenuates DSS-induced multi-organ inflammation via gut-liver-brain axis modulation through NF-κB and MAPK pathway inhibition in experimental colitis models.