Capilliposide A alleviates DSS-induced colitis by regulating the intestinal flora and its metabolites of origin

Ulcerative colitis is a chronic idiopathic inflammatory disease that impacts the mucous membrane of the colon. Lately, the incidence and prevalence of UC has been increasing globally. However, there are significant side effects of existing drugs for UC intervention. Accordingly, there is a pressing demand to explore novel bioactive substances for addressing UC. Natural product saponins have attracted great attention due to their obvious anti-colitis potential. Capilliposide A is a triterpenoid saponin, which is derived from Lysimachia capillipes Hemsl., exhibits good anti-inflammatory activity. Nonetheless, the impact and mechanism of CPS-A on ulcerative colitis remains obscure. This study aimed to investigate the therapeutic effects of CPS-A on the dextran sulphate sodium induced colitis mouse model and explore its mechanism. The efficacy and safety of CPS-A were evaluated in a well-established dextran sodium sulfate (DSS)-induced colitis mice model. Disease progression was monitored via clinical symptoms, histopathological examination, quantification of inflammatory cytokines, and epithelial barrier function evaluation. Plasma samples and intestinal contents were collected for non-targeted metabolomics and 16sRNA sequencing, respectively, to jointly evaluate the mechanism of action. CPS-A alleviated colitis by improving weight, Disease activity index score, histopathology, goblet cell, colon length, and expression of inflammatory factors. Moreover, CPS-A effectively preserved the integrity of the intestinal barrier by enhancing the expression of tight junction proteins and mucin in the colonic tissue of mice. Furthermore, CPS-A exerted a regulatory effect on the composition of the gut microbiota, promoting bacterial richness and diversity. It not only suppressed the abundance of detrimental bacteria while enhancing the abundance of advantageous bacteria, but also modulated the metabolites derived from the intestinal flora. Importantly, correlation analysis shows that these indicators are highly correlated. This study revealed that CPS-A exhibits a favorable therapeutic efficacy against colitis, primarily attributed to its ability to modulate the gut microbiota their associated metabolites as the key mechanisms of action.