Background: The bark of Ailanthus altissima (Mill.) Swingle (BAA), a widely used Chinese medicinal herb in traditional remedies for bowel disorders, has yet to be explored in the context of ulcerative colitis (UC), and its therapeutic mechanisms remain unclear.

Objective: This study integrated network pharmacology and experimental validation to investigate the effects and underlying mechanisms of BAA in treating UC.

Methods: First, UPLC-MS/MS analysis was employed to identify the chemical constituents of BAA. Network pharmacology was then applied to analyze the potential mechanisms of BAA based on these identified compounds. Lastly, a dextran sulfate sodium (DSS)-induced UC mouse model was utilized to assess BAA's therapeutic efficacy, with Western blotting performed to examine changes in protein expression within the key pathway influenced by BAA.

Results: UPLC-MS/MS and SwissADME analysis identified 223 active compounds in BAA. Network pharmacology suggested that the PI3K/AKT pathway may serve as a primary mechanism by which BAA exerts its anti-UC effects. In the DSS-induced UC mouse model, BAA significantly mitigated colonic injury, reduced DAI scores, and promoted weight recovery in mice. Additionally, BAA downregulated pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6, thereby suppressing inflammatory responses in the colon. Western blot analysis further demonstrated that BAA primarily inhibited the PI3K/AKT pathway in UC mouse colon tissue.

Conclusions: This study highlights that BAA effectively reduces colonic inflammation and preserves intestinal mucosal integrity, likely through the inhibition of PI3K/AKT pathway activity, positioning it as a potential treatment for UC.