Metabolic Activation-Dependent Anti-Liver Cancer Activity and Organ-Specific Toxicity of Retrorsine From Fanhuncao (Jacobaea cannabifolia and J. litvinovii).

Fanhuncao (Jacobaea cannabifolia and J. litvinovii) is a traditional Chinese herb with reported antitumor potential. Retrorsine, a pyrrolizidine alkaloid from Fanhuncao, requires CYP3A4‑mediated metabolic activation, but its dual outcomes (anti‑liver cancer efficacy vs. organ‑specific toxicity) remain unclear. To elucidate how CYP3A4-dependent activation of retrorsine drives both anti-liver cancer activity and organ-specific toxicity, and to identify differential cell death pathways in target organs. UPLC-HRMS profiled pyrrolizidine alkaloids in Fanhuncao. Cytotoxicity screening, molecular docking, and molecular dynamics identified retrorsine as the lead compound. Network pharmacology/toxicology predicted targets of dehydro-retrorsine. In vitro assays and Western blotting were performed on hepatoma cells. In vivo efficacy and toxicity were evaluated in H22 tumor-bearing mice. Retrorsine achieved significant tumor growth inhibition at high dose. Mechanistically, it simultaneously inhibited EGFR/PI3K/AKT/mTOR and NF-κB pathways while activating intrinsic mitochondrial apoptosis (altered Bax/Bcl-2, cytochrome c release, Caspase-9/3 activation). Retrorsine upregulated CYP3A4 in tumor cells, suggesting a potential self‑amplifying metabolic loop that requires further validation. However, this efficacy was accompanied by dose-dependent hepatorenal toxicity with organ-specific mechanisms: liver injury via oxidative stress and mitochondrial apoptosis; kidney injury via Caspase-3/GSDME-dependent pyroptosis. Retrorsine is a potent multi-target anti-liver cancer natural product, but its therapeutic window is narrowed by inseparable organ-specific toxicities (hepatic apoptosis vs. renal pyroptosis) arising from CYP3A4-dependent metabolic activation. Future decoupling strategies should focus on targeted delivery, structural modification, or combination therapies.