NEW BIOMIMETIC ANTIOXIDANTS WITH CATALASE AND SUPEROXIDE DISMUTASE ACTIVITY

DAIER, VERÓNICA; CLAUDIA PALOPOLI,; HERNÁN BIAVA,; DIEGO MORENO,; SANDRA SIGNORELLA,

BIOCELL

INST HISTOL EMBRIOL-CONICET

Año: 2007 vol. 31 p. 145 - 145

0327-9545

In a variety of pathological situations the production of reactive oxygen species overwhelms the activity of endogenous defence systems (catalases (CAT) and superoxide dismutases (SOD)). Re- newed interest has recently been stimulated by reports of catalytic antioxidants as novel therapeutics based on their ability to seques- ter oxidants at a much higher rate than stoichiometric antioxidants. Particularly attractive are complexes exhibiting combined CAT and SOD activity because they offer a possible therapeutic advantage arising from their multiple mechanism of action. With this in mind, we have evaluated the SOD and CAT activity of new Mn com- plexes of 1,3-bis(2-hydroxybenzyl-2-methylpyridylamino)propan- 2-ol (H3L1), 1,4-bis(salicylidenamino) butan-2-ol (H3L2), 1,5-bis(5- sulphonatesalicilidenamino)pentan-3-ol (H 3L 3) and 1,5-bis(2- hydroxybenzyl-2-methylpyridylamino)pentan-3-ol (H3L3 ). These ligands afford Mn complexes of different nuclearity, that are good structural mimics of MnSOD and MnCAT. The catalase activity was determined polarographically by measuring the oxygen con- centration of H2O2 + catalyst mixtures with a Clark-type oxygen electrode. The SOD activity was assayed by measuring the inhibi- tion of the photoreduction of nitro blue tetrazolium in the presence of the catalyst. Complexes Mn2 L1 and Mn2L4 , with Mn ions pos- sessing saturated coordination spheres, showed moderate CAT ac- tivity. Complex Mn2L 3 was found to be highly efficient to dispro- portionate H2 O2 in aqueous basic medium and is the most efficient MnCAT mimic known up to date. Complex MnL 2 was found to be an excellent catalyst with combined SOD/CAT activity.