Cobalt(II) complexes with 1,10-phenanthroline alone and mixed with cytoside: Synthesis and antibacterial activities

Abstract

Cobalt can bind to a range of biomolecules forming complexes that are suitable for use in various biological applications. Different ligands could be used to tune the properties of cobalt compounds whose ligand exchange rates become close to those of cellular processes.  In this study, two complexes were synthesized from 1,10-phenanthroline alone as [Co(phen)₂(H₂O)₂]Cl₂ and from both 1,10-phenanthroline and cytoside as [Co(phen)₂(Cyt)H₂O]Cl. The synthesis was checked using halide test, conductance measurement as well as spectroscopic (AAS, FTIR, Uv-vis) analysis. In vitro antibacterial activities of the two metal complexes were tested against Staphylococcus aureus, methicilin resistant staphylococcus aureus (MRSA), Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae and Shegella boydii. These complexes showed better activities than the commercially available control drugs (chloramphenicol and ciprofloxacin) against certain strains of bacteria. Better inhibition zones were exhibited by [Co(phen)₂(Cyt)(H₂O)]Cl on MRSA (4.8%) and E. coli (21.4%) than chloramphenicol. Likewise, 11.9% and 22.8% more zones of inhibition than ciprofloxacin were shown against MRSA and E. coli, respectively. On the other hand, [Co(Phen)₂(H₂O)₂]Cl showed 5.3% and 3.0% more zones of inhibition against S. aurous and S. boydii,  respectively, better than ciprofloxacin.