Eugenol inhibits quorum sensing at sub-inhibitory concentrations
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Updated: May 15, 2026

Quantification of Violacein in Chromobacterium violaceum and Its Inhibition by Bioactive Compounds
Published on: August 8, 2025
Liman Zhou1, Hongda Zheng, Yidan Tang
1Key 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
Unlabelled:
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.
Purpose Of The Work:
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.
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