The effects of a thiol-containing quinazolinedione derivative (MECH) on the lipid oxidation in bilayer liposomes

Abstract

In order to investigate the radical chemistry of 3-(2-mercaptoethyl)quinazoline-2,4(1H, 3H)-dione (MECH) in homogeneous and liposomal solutions experiments were performed with pulse radiolysis, γ radiolysis and the chemical radical intiator 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH). It is shown that the thiol group represents the most sensitive group to radical attack. The thiyl radical originating from MECH is detected indirectly by product analysis and by pulse radiolysis. The thiyl radical can abstract bisallylic hydrogens from polyunsaturated fatty acids. This is shown by pulse radiolysis in homogeneous and liposomal solutions via the formation of the pentadienyl radical which has a strong and characteristic absorption band at 280 nm.