Synthesis and characterization of new Cr(III), Fe(III) and Cu(II) complexes incorporating multi-substituted aryl imidazole ligand: Structural, DFT, DNA binding, and biological implications

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Mar 5:228:117700. doi: 10.1016/j.saa.2019.117700. Epub 2019 Nov 2.

Abstract

Designing new metal-based molecular antibiotics is an efficient approach to overcome the growing threat of antimicrobial resistance. In this paper, novel Cr(III), Fe(III) and Cu(II) complexes comprising substituted aryl imidazole ligand (MSEB), namely (2-(1-(2-hydroxyethyl)-4,5-diphenyl-1H-imidazole-2-yl)(4-bromophenol)) have been synthesized and characterized using infra-red (IR), ultraviolet-visible (UV-Vis) and 1H, 13C NMR spectroscopic techniques, together with elemental (CHN) and thermogravimetric analyses, molar conductance, and magnetic susceptibility measurements. The combined results along with the DFT calculations revealed a 1:1 (M: L) stoichiometric ratio and the complexes adopted distorted-octahedral geometries to afford [Cr(MSEB)Cl2(H2O)2], [Fe(MSEB)(NO3)2(H2O)2] and [Cu(MSEB)Cl(H2O)3] respectively. Biological studies showed that all complexes exhibited powerful antimicrobial activity against various strains of bacteria and fungi, S. aureus (+ve), E. coli (-ve) and P. aeruginosa (-ve) bacteria and T. Rubrum, C. albicans, and A. flavus fungi. Moreover, the three metal-complexes showed high in vitro cytotoxicity against Colon (HCT-116), Breast (MCF-7), and hepatic cellular (HepG-2) carcinoma cell lines, with MSEBCu complex being the most cytotoxic one. Finally the binding interactions of the complexes with CT-DNA were explored using UV-Vis spectroscopy, viscosity and gel electrophoreses measurements.

Keywords: Anticancer; Antimicrobial; Aryl imidazole metal chelates; DFT calculation; DNA interaction.

MeSH terms

  • Anti-Infective Agents / pharmacology
  • Antineoplastic Agents / pharmacology
  • Bacteria / drug effects
  • Carbon-13 Magnetic Resonance Spectroscopy
  • Cell Line, Tumor
  • Chromium / chemistry*
  • Coordination Complexes / chemical synthesis*
  • Copper / chemistry*
  • DNA / metabolism*
  • Density Functional Theory*
  • Electric Conductivity
  • Fungi / drug effects
  • Humans
  • Hydrogen-Ion Concentration
  • Imidazoles / chemical synthesis
  • Imidazoles / chemistry*
  • Inhibitory Concentration 50
  • Iron / chemistry*
  • Kinetics
  • Ligands
  • Magnetic Phenomena
  • Microbial Sensitivity Tests
  • Models, Molecular
  • Proton Magnetic Resonance Spectroscopy
  • Spectrophotometry, Infrared
  • Thermodynamics
  • Thermogravimetry
  • Viscosity

Substances

  • Anti-Infective Agents
  • Antineoplastic Agents
  • Coordination Complexes
  • Imidazoles
  • Ligands
  • Chromium
  • Copper
  • imidazole
  • DNA
  • Iron