Ethanol extract of Peucedani Japonici Radix enhances intestinal barrier function via regulating tight junctions

Peucedanum japonicum Thunberg (PJT) has attracted attention as a potential therapeutic agent due to its antioxidant and anti-inflammatory properties. The roots of PJT are commonly referred to as Peucedani Japonici Radix (PJR). This study investigated the effects of Peucedani Japonici Radix ethanol extract (PJRE) on intestinal barrier integrity and the underlying molecular mechanisms, with a focus on tight junctions (TJs). Antioxidant activity of PJRE was confirmed, and cell cytotoxicity was assessed in Caco-2 cells, revealing no adverse effects. Barrier function was evaluated using transepithelial electrical resistance (TEER) and FITC-dextran 4 kDa permeability assays, and the expression of tight junction proteins (TJPs) was analyzed. PJRE significantly attenuated IL-6 induced barrier dysfunction and preserved the expression of TJPs in vitro. Therapeutic efficacy was further assessed in a dextran sodium sulfate (DSS)-induced ulcerative colitis mouse model. PJRE administration alleviated clinical symptoms, reduced histopathological damage, and downregulated pro-inflammatory cytokines, while enhancing TJP expression, as confirmed by Western blot analysis. Additionally, liquid chromatography–tandem mass spectrometry (LC-MS/MS) identified eight bioactive compounds in PJRE, and molecular docking analyses suggested their potential interactions with TJPs. In conclusion, this study demonstrates that PJRE effectively protects and restores intestinal barrier integrity through antioxidant and anti-inflammatory mechanisms. Overall, PJRE serves as an effective agent for preserving intestinal barrier function and regulating TJs, and is a promising natural therapeutic candidate for the management of IBD particularly UC.