Synthesis and antioxidant activity of new tetraarylpyrroles

The synthesis and in vitro antioxidant activity of 17 new tetraarylpyrroles are investigated by 2 tests highly documented in the literature: capabilit y to prevent Fe2+-induced Lipid peroxidation on microsomes, which is a memb rane preparation rich in polyunsaturated fatty acids, and direct scavenging effect on a stable free radical, 1,1-diphenyl-2-picryl-hydrazyl (DPPH). Fo r the Fe2+-induced microsomal lipid peroxidation system, the results show t hat molecules which possess 2-pyrazinyl or 2-pyridyl in the 3- and 4-positi ons on the pyrrole ring are the most efficient. Introduction of methoxy gro ups on the phenyl ring in the 2- and 5-positions increases the effects but the higher activity is obtained with 2-furyl or 2-thienyl. The only compoun ds which possess a direct scavenger effect on trapping the stable free radi cal DPPH are those which have 2-pyridyl in the 3- and 4-positions and 2-fur yl or 2-thienyl in the 2- and 5-positions. (C) 1999 Editions scientifiques et medicales Elsevier SAS.