Centipeda minima (L.) A. Braun & Asch. and its representative active compound alleviate DSS-induced ulcerative colitis via inhibition of NLRP3 inflammasome activation and regulation of gut microbiota

Ulcerative colitis (UC) is a prevalent chronic inflammatory bowel disease (IBD), which is related to the occurrence of inflammation and intestinal flora disorder. Centipeda minima (L.) A. Braun & Asch. (CM for short hereafter) is commonly used to treat IBD in folk medicine. However, the anti-UC mechanisms of CM and its representative active compound(s) are not yet fully understood. Here, we sought to investigate the mode of action and the underlying mechanism of CM as an anti-UC agent, as well as to identify its potential bioactive compound(s). Results showed that 50% ethanol extract of CM (CME) significantly improved the pathological morphology and reduced the protein levels of NLRP3 both in DSS-induced UC mice model and lipopolysaccharide (LPS)-stimulated RAW264.7 cell model. Additionally, it decreased the release of proinflammatory cytokines including TNF-α, IL-18 and IL-1β. These results suggest that the anti-UC effect of CM is at least partially attributed to the inhibition of NLRP3 inflammasome activation. Furthermore, luteolin, a representative active compound in CM, exhibited significant improvement of the pathological changes, reduced the release the of proinflammatory cytokines, downregulated NLRP3 inflammasome activation, enhanced intestinal barrier, and modulated gut microbiota in vivo. This study provides a molecular rationale for the traditional use of CM in treating UC, and offers a pharmacological basis for the development of modern anti-UC agents derived from CM.