Tong Li ^* shoupeng fu ^* Di Qin ^* yuan ju ^* Zheyu Song ^* qiu Hui ^*

• Jilin University, Changchun, China

Phillyrin (PHY), also known as forsythin, is one of the active constituents isolated from the fruits of Forsythia suspensa (Thunb.) Vahl (Oleaceae). It exhibits antiinflammatory, antiviral, and antioxidant properties. However, the precise impact of PHY on colitis induced by dextran sodium sulfate (DSS) and its mechanism remains elusive. The present investigation revealed that PHY (12.5, 25, and 50 mg/kg) exhibited significant therapeutic efficacy in protecting mice against DSS-induced colitis. This effect was manifested as reduced weight loss, shortened colon, increased secretion of inflammatory factors, increased intestinal permeability, and enhanced disease activity index (DAI) in Ulcerative Colitis (UC) mice. Molecular investigations have elucidated that PHY mitigates the nuclear translocation of nuclear factor kappa B (NF-κB), thereby downregulating Myosin Light-chain kinase (MLCK)-driven MLC phosphorylation (p-MLC). This mechanism results in the preservation of the integrity of the intestinal barrier. The outcomes of 16S rRNA sequencing suggested that PHY (50 mg/kg) augmented the relative abundance of certain probiotic strains, including Lactobacillaceae and Lachnospiraceae. Additionally, PHY supplementation elevated the short-chain fatty acid contents within the intestinal contents of UC mice. In summary, pre-treatment with PHY may ameliorate the DSS-induced UC in mice by lowering the expression of inflammatory factors, protecting intestinal barrier function, and enhancing the structure of intestinal flora.