Discovery and Optimization of A 2-Phenyl-1,2,4-triazolidin-3-one Scaffold as Potent Ferroptosis Inhibitors for Hepatoprotection

Ferroptosis is a regulated form of cell death that plays a critical role in the initiation and progression of various liver diseases. Identifying novel ferroptosis inhibitors may therefore offer promising therapeutic benefits for ferroptosis-related liver diseases. Through screening of a small-molecule compound library, we identified 7,7,9-trimethyl-2-(o-tolyl)-1,2,4-triazaspiro[4.5]decan-3-one as a hit with moderate ferroptosis inhibitory activity (EC 50 = 84 nM). Its core scaffold, 2-Phenyl-1,2,4-triazolidin-3-one (TZN), was subsequently optimized via a rapid synthetic route. Among the resulting derivatives, TZN-23 potently suppressed ferroptosis across multiple cell lines (EC 50 = 13 nM) and counteracted cell death induced by diverse ferroptosis inducers. Mechanistic studies demonstrated that TZN-23 directly scavenges lipid peroxidation in vitro , thereby suppressing ferroptosis. DMPK studies revealed that TZN-23 exhibited favorable microsomal stability with slow phase I metabolism, along with good plasma exposure and oral bioavailability in mice. Moreover, the high drug concentrations observed in both liver and brain suggest its potential for controlling ferroptosis in hepatic or cerebral contexts. Accordingly, TZN-23 effectively alleviated concanavalin A (ConA)-induced acute liver injury in mice by inhibiting ferroptosis. Collectively, this work identifies a series of novel ferroptosis inhibitors, serving as potent tool molecules for investigating ferroptosis and offering potential therapeutic strategies for ferroptosis-related diseases.