Toosendanin Induces Hepatotoxicity by Facilitating ALOX5-Mediated Lipid Peroxidation and Sensitizing Cells to Ferroptosis.

: (FMT) is a traditional Chinese medicine used to treat ascariasis; however, its reported hepatotoxicity limits its application. Toosendanin (TSN), as a principal active component, is recognized as the primary toxic ingredient responsible for FMT-induced hepatotoxicity, but the underlying mechanisms remain elusive. : HepG2 cells were treated with TSN and analyzed using Western blotting and qPCR assays for related gene transcription and protein expression. Lipid peroxidation and ferroptosis markers were measured. Balb/c and C57BL/6 mice received various doses of TSN administration, and their liver function was assessed with serum biochemistry and histopathology. Network pharmacology and oxidative lipidomics were performed to identify key targets and metabolites. TSN triggered ferroptosis both in vitro and in vivo, accompanied by the elevated expression of 5-lipoxygenase (ALOX5) and its downstream metabolites. The ALOX5 level modulated hepatocyte sensitivity to TSN-induced ferroptotic damage. An ALOX5 knockdown alleviated TSN-induced liver injury and ferroptosis in vivo. : Our study demonstrated that TSN induces hepatotoxicity by facilitating ALOX5-mediated lipid peroxidation, thereby sensitizing cells to ferroptosis.