In vitro evaluation of Zn-norfloxacin complex as a potent cytotoxic and antibacterial agent, proposed model for DNA binding

Appl Biochem Biotechnol. 2013 Jun;170(4):988-1009. doi: 10.1007/s12010-013-0255-6. Epub 2013 May 1.


A tetrahedral Zn(II) complex with the second generation fluoroquinolone, norfloxacin, was prepared and characterized (NOR-Zn complex, NZC). The antibacterial efficiency of the NZC was tested on two Gram-positive and four Gram-negative bacteria by minimum inhibitory concentration method. The cytotoxic potential of NZC on MDA (human breast adenocarcinoma), Caco-2 (human colon adenocarcinoma), and Hela (human cervix carcinoma) cell lines was studied. The DNA interaction property of the NZC has been investigated using UV-vis, fluorescence, Fourier transform infrared, as well as cyclic voltammetry methods. Intrinsic binding constant (K(b)), thermodynamic, and other spectroscopic and voltammetric data indicate that the NZC has more affinity for DNA than for norfloxacin and interacted with DNA via two modes: electrostatic and outside hydrogen binding. The proposed DNA binding mode supports the large enhancement in the cytotoxicity and antibacterial activity of NZC.

MeSH terms

  • Animals
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology*
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Caco-2 Cells
  • Drug Screening Assays, Antitumor
  • Enterococcus faecalis / drug effects
  • HeLa Cells
  • Humans
  • Hydrogen Bonding
  • Macromolecular Substances / pharmacology
  • Microbial Sensitivity Tests
  • Models, Molecular
  • Norfloxacin / chemistry
  • Norfloxacin / pharmacology*
  • Proteus mirabilis / drug effects
  • Static Electricity
  • Zinc / chemistry
  • Zinc / pharmacology*


  • Anti-Bacterial Agents
  • Antineoplastic Agents
  • Macromolecular Substances
  • Zinc
  • Norfloxacin