title: Macrocyclic copper(II) complexes: superoxide scavenging activity, structural studies and cytotoxicity evaluation.
abstract: Synthetic superoxide dismutase mimetics have emerged as a potential novel class of drugs for the treatment of oxidative stress related diseases. Among these agents, metal complexes with macrocyclic ligands constitute an important group. In this work we synthesized five macrocyclic copper(II) complexes and evaluated their ability to scavenge the superoxide anions generated by the xanthine-xanthine oxidase system. Two different endpoints were used, the nitro blue tetrazolium (NBT) reduction assay (colorimetric method) and the dihydroethidium (DHE) oxidation assay (fluorimetric method). IC(50) values in the low micromolar range were found in four out of five macrocyclic complexes studied, demonstrating their effective ability to scavenge the superoxide anion. The IC(50) values obtained with the NBT assay for the macrocyclic copper(II) complexes, were consistently higher, approximately threefold, than those obtained with the DHE assay. Spectroscopic and electrochemical studies were performed in order to correlate the structural features of the complexes with their superoxide scavenger activity. Cytotoxicity assays were also performed using the MTT method in V79 mammalian cells and we found that the complexes, in the range of concentrations tested in the superoxide scavenging assays were not considerably toxic. In summary, some of the presented macrocyclic copper(II) complexes, specially those with a high stability constant and low IC(50), appear to be promising superoxide scavenger agents, and should be considered for further biological assays.
authors: CECF, Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal.
authors: Ana S
authors: AS
authors: Fernandes
authors: Jorge
authors: J
authors: Gaspar
authors: M Fátima
authors: MF
authors: Cabral
authors: Cátia
authors: C
authors: Caneiras
authors: Rita
authors: R
authors: Guedes
authors: José
authors: J
authors: Rueff
authors: Matilde
authors: M
authors: Castro
authors: Judite
authors: J
authors: Costa
authors: Nuno G
authors: NG
authors: Oliveira
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003124:Colorimetry; D003300:Copper / Q000737:chemistry*; D006224:Cricetinae; D003412:Cricetulus; D004578:Electron Spin Resonance Spectroscopy; D004996:Ethidium / Q000031:analogs & derivatives / Q000737:chemistry; D005470:Fluorometry; D005562:Formazans; D016166:Free Radical Scavengers / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D047028:Macrocyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D009580:Nitroblue Tetrazolium / Q000737:chemistry; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D011199:Potentiometry; D013481:Superoxides / Q000737:chemistry*; D013778:Tetrazolium Salts
chemical_list: D005562:Formazans; D016166:Free Radical Scavengers; D047028:Macrocyclic Compounds; D009942:Organometallic Compounds; D013778:Tetrazolium Salts; C067883:dihydroethidium; D013481:Superoxides; C079782:MTT formazan; D009580:Nitroblue Tetrazolium; D003300:Copper; D004996:Ethidium