Re-evolution of the 2-phenylquinolines: ligand-based design, synthesis, and biological evaluation of a potent new class of Staphylococcus aureus NorA efflux pump inhibitors to combat antimicrobial resistance

J Med Chem. 2013 Jun 27;56(12):4975-89. doi: 10.1021/jm400262a. Epub 2013 Jun 13.

Abstract

Overexpression of efflux pumps is an important mechanism by which bacteria evade the effects of antimicrobial agents that are substrates. NorA is a Staphylococcus aureus efflux pump that confers reduced susceptibility to many structurally unrelated agents, including fluoroquinolones, biocides, and dyes, resulting in a multidrug resistant (MDR) phenotype. In this work, a series of 2-phenylquinoline derivatives was designed by means of ligand-based pharmacophore modeling in an attempt to identify improved S. aureus NorA efflux pump inhibitors (EPIs). Most of the 2-phenylquinoline derivatives displayed potent EPI activity against the norA overexpressing strain SA-1199B. The antibacterial activity of ciprofloxacin, when used in combination with some of the synthesized compounds, was completely restored in SA-1199B and SA-K2378, a strain overexpressing norA from a multicopy plasmid. Compounds 3m and 3q also showed potent synergistic activity with the ethidium bromide dye in a strain overexpressing the MepA MDR efflux pump.

MeSH terms

  • Anti-Bacterial Agents / chemical synthesis
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology
  • Bacterial Proteins / antagonists & inhibitors*
  • Chemistry Techniques, Synthetic
  • Computer-Aided Design
  • Drug Design*
  • Drug Evaluation, Preclinical
  • Drug Resistance, Bacterial / drug effects*
  • Inhibitory Concentration 50
  • Ligands
  • Microbial Sensitivity Tests
  • Models, Molecular
  • Molecular Conformation
  • Multidrug Resistance-Associated Proteins / antagonists & inhibitors*
  • Quinolines / chemical synthesis
  • Quinolines / chemistry*
  • Quinolines / pharmacology*
  • Staphylococcus aureus / drug effects*
  • Structure-Activity Relationship

Substances

  • 2-phenylquinoline
  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Ligands
  • Multidrug Resistance-Associated Proteins
  • Quinolines
  • NorA protein, Staphylococcus