Quercetin alleviates ulcerative colitis via regulating gut microbiota and tryptophan metabolism

Abstract

Ulcerative colitis is a chronic inflammatory disease with limited effective therapeutic options. In this study, quercetin—a flavonoid commonly found in traditional Chinese medicinal herbs—was shown to relieve colitis symptoms by reshaping gut microbiota and restoring tryptophan metabolism. Notably, the increase in indolelactic acid, a key microbial metabolite, led to activation of the aryl hydrocarbon receptor, which supports intestinal barrier integrity and dampens inflammation. These findings reveal a gut microbiota-derived metabolite-host signaling axis as a central mechanism of action, highlighting the potential of quercetin as a microbiota-targeted therapeutic approach for UC.