Synthesis and Assessment of Antibacterial Activities of Ruthenium(III) Mixed Ligand Complexes Containing 1,10-Phenanthroline and Guanide

Abstract

In this work, two complexes of ruthenium(III) ([Ru(phen)₂Cl₂]Cl·2H₂O and [Ru(phen)₂(G)Cl]2Cl·H₂O) were synthesized from 1,10-phenanthroline alone as well as from both 1,10-phenanthroline and guanide. The synthesis was checked using halide test, conductance measurement, and spectroscopic (ICP-OES, FTIR, and UV/Vis) analysis. Their in vitro antibacterial activities were also investigated on two Gram-positive (<i>Staphylococcus aureus</i> (<i>S. aureus</i>) and methicillin resistant <i>Staphylococcus aureus</i> (MRSA)) and two Gram-negative (<i>Escherichia coli</i> (<i>E. coli</i>) and <i>Klebsiella pneumoniae</i> (<i>K. pneumoniae</i>)) bacteria. These complexes showed wide-range better activities than the commercially available controls (Chloramphenicol and Ciprofloxacin) against even the most drug resistant <i>K. pneumoniae</i>. [Ru(phen)₂(G)Cl]2Cl·H₂O inhibited <i>S. aureus</i>, MRSA, <i>E. coli</i>, and <i>K. pneumoniae</i> by 17.5%, 27.4%, 16%, and 52%, respectively, better than Chloramphenicol. It also inhibited these pathogens by 5.9%, 5.1%, 2.3%, and 17.2%, respectively, better than Ciprofloxacin. Similarly, [Ru(Phen)₂(Cl)₂]Cl·2H₂O inhibited these pathogens by 11%, 8.7%, 0.1%, and 31.2%, respectively, better than Chloramphenicol. Therefore, after in vivo cytotoxicity investigations, these compounds can be considered as potential antibiotic drugs.