title: Neutral and cationic mononuclear copper(II) complexes with enrofloxacin: structure and biological activity.
abstract: The mononuclear copper complexes with the quinolone antibacterial drug enrofloxacin (=Herx) in the presence or not of a nitrogen donor heterocyclic ligand 1,10-phenanthroline (=phen) and 2,2'-bipyridine (=bipy) have been prepared and characterized. Interaction of copper(II) with deprotonated enrofloxacin leads to the formation of the neutral complex Cu(erx)2(H2O), 1, while the presence of phen or bipy leads to the formation of a neutral or a cationic mononuclear complex, respectively. The crystal structures of (chloro)(1,10-phenanthroline)(enrofloxacinato)copper(II), 2, and (aqua)(2,2'-bipyridine)(enrofloxacinato)copper(II) chloride, 3, have been determined with X-ray crystallography. The complexes have been studied with X-band electron paramagnetic resonance in aqueous solutions at liquid helium temperature. The study of the interaction of the complexes with calf-thymus DNA has been performed with diverse spectroscopic techniques and has showed that all complexes are bound to DNA by the intercalative mode. The antimicrobial efficiency of the complexes has been tested on three different microorganisms and the available evidence supports that the best inhibition is provided by Cu(erx)2(H2O) (minimum inhibitory concentration=0.125 microg mL(-1)) against Escherichia coli and Pseudomonas aeruginosa.
authors.affiliation: Institute of Physical Chemistry, NCSR "Demokritos", 15310 Aghia Paraskevi Attikis, Greece.
authors.forename: Eleni K
authors.initials: EK
authors.lastname: Efthimiadou
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Sanakis
authors.forename: Maria
authors.initials: M
authors.lastname: Katsarou
authors.forename: Catherine P
authors.initials: CP
authors.lastname: Raptopoulou
authors.forename: Alexandra
authors.initials: A
authors.lastname: Karaliota
authors.forename: Nikos
authors.initials: N
authors.lastname: Katsaros
authors.forename: George
authors.initials: G
authors.lastname: Psomas
mesh_terms: D000890:Anti-Infective Agents / Q000138:chemical synthesis* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D002412:Cations; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D000077422:Enrofloxacin; D024841:Fluoroquinolones / Q000737:chemistry* / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D013055:Spectrophotometry, Infrared
chemical_list: D000890:Anti-Infective Agents; D002412:Cations; D024841:Fluoroquinolones; D000077422:Enrofloxacin; D003300:Copper; D004247:DNA