Third generation fluoroquinolones antibacterial drug based mixed-ligand Cu(II) complexes: structure,antibacterial activity,superoxide dismutase activity and DNA–interaction approach

The copper(II) complexes of the type Cu(SPF)(Aⁿ)Cl]/Cu(PFL)(Aⁿ)Cl] (where SPF is sparfloxacin, PFL is pefloxacin and Aⁿ is 2,2′-dipyridylamine/pyridine-2-carboxalehyde/thiophene-2-carboxaldehyde) were synthesised and were found to have a pyramidal geometry with a square base. The superoxide dismutase (SOD) like activity of the complexes were measured using an NBT/NADH/PMS system, these were expressed in terms of the concentration of complex which termianates the formation of formazan by 50% (IC₅₀ value) and found to range from 0.781 to 1.354 μM. The interactions of the complexes with DNA were studied by absorption titration, viscosity measurement and gel electrophoresis under physiological conditions. The antimicrobial efficiency of the complexes were tested on five different microorganisms and showed good biological activity.