title: Eugenol inhibits quorum sensing at sub-inhibitory concentrations.
abstract: In bacteria, quorum sensing (QS) is a process of chemical communication involving the production, release, and subsequent detection of signaling molecules. QS regulates the production of key virulence factors in pathogens. During the screening of herbal extracts, clove extract was found to inhibit QS-controlled gene expression in Pseudomonas aeruginosa QSIS-lasI and Chromobacterium violaceum CV026 biosensors. Using a bioautographic TLC assay, preparative TLC, and HPLC analysis, eugenol, the major constituent of clove extract, exhibited QS inhibitory activity. Eugenol at sub-inhibitory concentrations inhibited the production of virulence factors, including violacein, elastase, pyocyanin, and biofilm formation. Using two Escherichia coli biosensors, MG4/pKDT17 and pEAL08-2, we confirmed that eugenol inhibited the las and pqs QS systems. Our data identified eugenol as a novel QS inhibitor.
  
  
  OBJECTIVE
  The purpose of this study was to track the quorum sensing inhibitor (QSI) in herbal extracts by effective screening systems and evaluate its biological activity. The QSIs from herbal extracts are potential agents for the treatment of bacterial infections.
authors.affiliation: Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, People's Republic of China. zhouliman88@126.com
authors.forename: Liman
authors.initials: L
authors.lastname: Zhou
authors.forename: Hongda
authors.initials: H
authors.lastname: Zheng
authors.forename: Yidan
authors.initials: Y
authors.lastname: Tang
authors.forename: Wengong
authors.initials: W
authors.lastname: Yu
authors.forename: Qianhong
authors.initials: Q
authors.lastname: Gong
mesh_terms: D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D002861:Chromobacterium / Q000187:drug effects* / Q000502:physiology; D004926:Escherichia coli / Q000187:drug effects* / Q000502:physiology; D005054:Eugenol / Q000302:isolation & purification / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000502:physiology; D053038:Quorum Sensing / Q000187:drug effects*; D027842:Syzygium / Q000737:chemistry; D037521:Virulence Factors / Q000096:biosynthesis
chemical_list: D000900:Anti-Bacterial Agents; D037521:Virulence Factors; D005054:Eugenol