Synthesis of Mixed Ligand Ruthenium (II/III) Complexes and Their Antibacterial Evaluation on Drug-Resistant Bacterial Organisms

Authors:
Open Access
Publisher website
Google Scholar
Abstract
The potential antimicrobial properties of a tridentate polypyridyl ligand 4-butoxy-N,N-bis(pyridin-2-ylmethyl)aniline (BUT) 1 and its corresponding mixed ligand ruthenium complexes were investigated on drug-resistant and non-drug-resistant bacterial species. The ligand and its complexes were synthesized and successfully characterized by1H NMR, UV/Vis, and FTIR spectra; ESI-MS; and magnetic susceptibility. Electronic spectra and magnetic susceptibility of these Ru(II)/(III) complexes suggest that they are of a low spin crystal field split, where the Ru(III) is ad5and Ru(II)d6low spin. These compounds were tested for antibacterial activity on two bacterial species:Staphylococcus aureus(S. aureus) andKlebsiella pneumoniae(K. pneumoniae), as well as their drug-resistant strains methicillin-resistantStaphylococcus aureus(MRSA) and multidrug resistantKlebsiella pneumoniae(MDRK. pneumoniae). All the compounds inhibited growth of the two non-drug-resistant bacteria and only one drug-resistant strain MRSA. However, only the ligands BUT and 2,2-dipyridylamine showed activity against MRSA, while all complexes did not show any antibacterial activity on MRSA. We observed large zones of inhibition for the Gram-positiveS. aureusand MRSA bacteria, compared to the Gram-negativeK. pneumoniaebacteria. DNA cleavage studies with gel electrophoresis showed denatured bacterial DNA on the gel from all the complexes, with the exception of the ligand, suggesting DNA nuclease activity of the complexes in the bacterial DNA.
Funding Information
  • Botswana International University of Science and Technology
  • University of Botswana Office of Research and Development

This publication has 30 references indexed in Scilit: