Identification of Isoliensinine as a Ferroptosis Suppressor with Iron-Chelating Activity

Ferroptosis is a type of regulated cell death driven by the iron-dependent accumulation of lipid peroxides. The high involvement of ferroptosis in diverse human diseases highlights the need for the identification of new chemotypes with anti-ferroptotic activity. Here, we performed a natural product library screening in HT1080 fibrosarcoma cells and identified licochalcone A (LA), isoeugenyl acetate (ISA), and isoliensinine (ISL) as suppressors of either RSL3- or IKE-induced ferroptosis. Mechanistically, ferroptosis resistance conferred by these compounds is mainly through GPX4/NRF2-independent mechanisms. Among them, only ISL could effectively rescue ferroptosis induced by FINO₂, which is a stable oxidant of ferrous iron, suggesting that ISL may have the properties of an iron chelator. Consistent with the hypothesis, both computational tools and X-ray photoelectron spectroscopy supported the binding between ISL and iron ions. And ISL greatly inhibited excessive iron-dependent ferroptotic cell death through limiting intracellular iron accumulation. Furthermore, its iron chelator activity also protected mice from organ injury in an acute iron overload model. In conclusion, this study provided valuable insights for developing effective anti-ferroptosis agents from natural products, which represent a potential therapeutic strategy for treating ferroptosis-associated organ damage.