Characterization of transient species produced from laser flash photolysis of a new cardioprotective drug: S-propargyl-cysteine

S-propargyl-cysteine (SPRC), a sulfur-containing amino acid, was proved to have cardioprotective effect mediated by the CSE/H2S pathway. In this study, photo-ionization of SPRC was investigated by 266 nm laser flash photolysis. Irradiated by 266 nm laser pulse, SPRC in aqueous solution experienced photo-ionization via a bi-photon process to produce hydrated electron, anion radical (SPRC−), and neutral radical (SPRC(–H)). The reaction of SPRC with SPRC− was found and the pKa of SPRC+ was determined. Oxidation of SPRC by SO4− not only confirmed the assignment of SPRC(–H), but also provided an evidence for the antioxidant activity of SPRC.