Superoxide Dismutase-Mimicking Activities of Dinuclear Cu(II) Complexes with Ligands Containing a Tetrathioether-Tetraamino Moiety


GUNER S., KARABÖCEK S.

JOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, cilt.12, ss.53-59, 1998 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 12 Konu: 1
  • Basım Tarihi: 1998
  • Dergi Adı: JOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY
  • Sayfa Sayıları: ss.53-59

Özet

The superoxide scavenging activities of copper(II) complexes with the ligands, 6,6'-methylene-bis(5'-amino-3',4'-benzo-2'-thiapentyl)-1,11-diamino-2,3:9,10-dibenzo-4,8-dithiaundecane (H4L), and 6,6'-bis(5'-amino-3',4'-benzo-2'-thiapentyl)-1,11-diamino-2,3:9,10-dibenzo-4,8-dithiaundecane (H4L ''), were investigated by xanthine xanthine oxidase (X/XO) assays using nitroblue tetrazolium (NBT) as indicator molecule, and the results were compared with respect to the particular type of anion (ClO4 center dot, Cl-center dot, NO3 center dot) on the apical site of the copper(II) complexes. All of the complexes inhibited the reduction of NBT by superoxide radicals, with the [Cu-2(L')](ClO4)(2) complex exhibiting the highest scavenging activity against superoxide radicals among the complexes examined. The catalytic efficiency of the complexes for dismutation of superoxide radicals depends on the particular anion liganded to Cu(II) ion in the complexes, and the order of potency was observed to be ClO4 > Cl > NO3 center dot in phosphate buffer at pH 7.40. The Cu(II)-H4L' complexes had the lowest IC50 and catalytic rate constant values indicating that the distorted geometry of the Cu(II)-H4L' complexes influence their catalytic activities for dismutation of superoxide radicals more efficiently. The difference in the activities of the complexes toward superoxide radicals can also be attributed to the nature of the anions on the apical site of the copper(II) complexes and the superoxide dismutase-like activity. (C) 1997 John Wiley & Sons, Inc. J Biochem Toxicol 12: 53-59, 1998