Integrated microbiomic and metabolomics insight into the ameliorating mechanisms of dietary Polygonatum cyrtonema saponin on ulcerative colitis

The occurrence and evolution of colitis can cause prejudicial damage to the intestinal barrier, with studies reporting positive effects of saponins on intestinal inflammation. Nevertheless, there is a lack of evidence regarding whether Polygonatum cyrtonema Saponin (PCS) can be employed as a food supplement ingredient to restore the intestinal barrier caused by dextran sodium sulfate (DSS). Here, the potential repair mechanisms of PCS on the intestinal barrier were intensively investigated via 16 S rRNA sequencing and non-targeted metabolomics techniques. The results showed that PCS intake effectively alleviated symptoms such as weight loss and colonic injury in DSS mice, reduced excessive inflammation, and restored intestinal barrier integrities via diminishing intestinal permeability and enhancing tight junction protein expression. Moreover, 16 S rRNA sequence analysis demonstrated that PCS could ameliorate the DSS-disrupted gut microbiota imbalances, especially restoring the abundance of Lactobacillus. Simultaneously, the favorable regulation of the gut microbiota was further bolstered from the improved short-chain fatty acids (SCFAs) profile, with a remarkable improvement in the contents of SCFAs by PCS. In addition, alterations in metabolites caused by the PCS intervention correlated significantly with the gut microbiota and PCS intervention subsequently modulated inflammation-associated metabolic pathways, in terms of amino acid metabolisms, ascorbate and aldarate metabolisms, and pyrimidine metabolisms. Collectively, our findings demonstrated that PCS can effectively mitigate intestinal inflammation, which may offer important perspectives for the preventions and treatments of intestinal disorders.