Synthesis and pharmacological screening of novel meso-substituted porphyrin analogs.

A novel series of mesotetrakis[aryl]-21H,23H-porphyrin derivatives 2a-j was synthesized from the condensation of aldehyde derivatives 1a-j with pyrrole in the presence of p-toluenesulfonic acid. The synthesized porphyrins were considered as a model to study the free radical-induced damage of biological membranes and the protective effects of these porphyrins. It was found that these compounds effectively inhibit the free radical-induced oxidative hemolysis of red blood cells. Compounds 2c and 2d which bear a sulfur atom, a nitro group, and a chlorine atom exhibited markedly higher antihemolysis activity than the other analogous. Compounds 2a, 2c, 2d, and 2j showed the highest protection activity against DNA damage induced by the bleomycin-iron complex. Compounds 2d, 2f, 2i, and 2j were proved to exhibit antioxidative activity.