Eugenol exhibits anti-virulence properties by competitively binding to quorum sensing receptors

Biofouling. 2017 Sep;33(8):624-639. doi: 10.1080/08927014.2017.1350655. Epub 2017 Aug 9.

Abstract

The primary objective of this study was to ascertain the anti-biofilm and anti-virulence properties of sub-minimum inhibitory concentration (MIC) levels of eugenol against the standard strain PAO1 and two multi-drug resistant P. aeruginosa clinical isolates utilizing quorum sensing inhibition (QSI). Eugenol at 400 μM significantly reduced biofilm formation on urinary catheters and the virulence factors (VF) including extracellular polysaccharides, rhamnolipid, elastase, protease, pyocyanin, and pyoverdine (p < 0.001). Further, eugenol exhibited a marked effect on the production of QS signals (AIs) (p < 0.001) without affecting their chemical integrity. In silico docking studies demonstrated a stable molecular binding between eugenol and QS receptor(s) in comparison with respective AIs. Investigation on reporter strains confirmed the competitive binding of eugenol to a QS receptor (LasR) as the possible QSI mechanism leading to significant repression of QS associated genes besides the VF genes (p < 0.001). This study provides insights, for the first time, into the mechanism of the anti-virulence properties of eugenol.

Keywords: Catheter associated urinary tract infections; Pseudomonas aeruginosa; biofilm; eugenol; quorum sensing; virulence factors.

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Binding, Competitive
  • Biofilms / drug effects*
  • Eugenol / pharmacology*
  • Microbial Sensitivity Tests
  • Molecular Docking Simulation
  • Pseudomonas aeruginosa / drug effects*
  • Pseudomonas aeruginosa / metabolism
  • Pseudomonas aeruginosa / pathogenicity
  • Quorum Sensing / drug effects*
  • Urinary Catheters / microbiology
  • Virulence
  • Virulence Factors / metabolism*

Substances

  • Anti-Bacterial Agents
  • Virulence Factors
  • Eugenol