Antiradical activity of morpholine- and piperazine-functionalized triphenylantimony(V) catecholates

The antiradical activity of the functionalized triphenylantimony(V) catecholates Ph3Sb[4-O(CH2CH2)2N-3,6-DBCat] (I), Ph3Sb[4,5-Piperaz-3,6-DBCat] (II), and Ph3Sb[4-PhN(CH2CH2)2N-3,6-DBCat] (III) (where [4-O(CH2CH2)2N-3,6-DBCat]2−, [4,5-Piperaz-3,6-DBCat]2−, and [4-PhN(CH2CH2)2N-3,6-DBCat]2− are the dianionic ligands 3,6-di-tert-butyl-4-(morpholin-1-yl)-, 3,6-di-tert-butyl-4,5-(piperazine-1,4-diyl)-, and 3,6-di-tert-butyl-4-(4-phenylpiperazin-1-yl)catecholates, respectively) was studied in reactions with the diphenylpicrylhydrazyl radical during autooxidation of unsaturated fatty (oleic and linoleic) acids with lipid peroxidation of Russian sturgeon (Acipenser gueldenstaedti B.) sperm and human blood erythrocytes in vitro as examples. The EC50 and n DPPH values obtained indicate the high antiradical activity of complexes II and III in the reactions with the stable radical. On the whole, complexes I–III inhibit the lipid peroxidation in both model (oxidation of unsaturated fatty acids) and in vitro experiments. The inhibiting effects of the complexes are comparable with and even, in some cases, higher than those of the known antioxidant ionol.