Oleanolic acid 28-O-β-D-glucopyranoside: A novel therapeutic agent against ulcerative colitis via anti-inflammatory, barrier-preservation, and gut microbiota-modulation.

Ulcerative colitis (UC), an incurable and recurrent inflammatory bowel disease, presents a significant threat to health and highlights the need for novel therapeutic strategies. Oleanolic acid 28-O-β-D-glucopyranoside (OAG) is a naturally occurring pentacyclic triterpenoid found in ginseng. In this study, we demonstrated that OAG exhibited remarkable anti-UC activity in LPS-induced Caco-2 cells and DSS-induced model mice. First, OAG alleviated the symptoms of UC by mitigating weight loss, reducing the DAI score, and increasing colon length. Second, the inflammatory response was inhibited after OAG intervention, evidenced decreases in the spleen coefficient, cytokine levels, and inflammatory cell infiltration in colon tissue. Thirdly, OAG also enhanced intestinal epithelial barrier function, as evidenced by elevated TEER values, increased expression of tight junction proteins, diminished bacterial translocation, and maintained intact ultrastructure of colonic mucosal cells. Notably, compared with 5-aminosalicylic acid, OAG demonstrated superior efficacy in enhancing mucosal barrier function. Fourth, OAG increased microbial diversity, promoted the abundance of beneficial bacteria, reduced the abundance of harmful bacteria, and rebalanced the gut microbiome. Finally, the PI3K-AKT and MAPK signaling pathways were identified as crucial mechanisms underlying the therapeutic effects of OAG against UC through multi-omics. In summary, we identified OAG as a novel therapeutic agent against UC, demonstrating anti-inflammatory, barrier-preserving, and gut microbiota-modulating effects, highlighting its promising potential as a candidate UC drug.