Chronic Exposure to Sunset Yellow Promotes Susceptibility to Experimental Colitis in Mice through Gut Microbiota

Sunset yellow (SY) is a widely used food additive. However, its impacts on ulcerative colitis (UC) development remain unclear. Here, SY exposure exacerbated dextran sulfate sodium (DSS)-induced UC symptoms in mice, including body weight loss, elevated disease activity index, histological damage, inflammation, gut barrier impairment, disruption of gut microbiota composition, and sulfur metabolism. Moreover, fecal microbiota transplantation from SY-exposed mice also exacerbated colitis in the recipient mice. Notably, SY exposure both in vivo and in vitro inhibited the growth of Akkermansia muciniphila (AKK). Nontargeted metabolomics revealed that SY exposure impaired glutathione (GSH) metabolism, as evidenced by reduced GSH and glutathione disulfide levels in both normal and colitis mice. In AKK, SY exposure significantly decreased GSH content, suppressed glutathione S-transferase activity, and disrupted sulfur metabolism. Importantly, GSH supplementation markedly reversed the SY-induced AKK growth inhibition. Collectively, these findings suggest that long-term SY exposure promotes experimental colitis in mice through gut microbiota-dependent GSH metabolic dysregulation.