Background: Quorum sensing or the bacterial information flow in an orchestrated
manner is an essential feature of many pathogenic bacteria. Quorum
quenching molecules (QQ) can inhibit the growth of such bacteria.
Objective: The purpose of this study is to evaluate the potential of plant extracts as
quorum quenchers and monitor the recent patents.
Methods: Many available reports and patents are on synthetic ligand molecules or
even compounds isolated from cyanobacteria (Honaucin A) and other microorganisms
inhibiting quorum sensing molecules. Molecules with Quorum quenching (QQ)
ability isolated from plants could inhibit violacein and pyocyanin production in
Chromobacterium violaceum and Pseudomonas aeruginosa respectively.
Results: Studies leading to patents are initiated in this comparatively new topic. Hydrolysable tannins
such as vescalagin and castalagin isolated from Conocarpus erectus are reported to have anti- quorum
sensing activity. The gene product of agr D in gram positive bacteria is modified by endopeptidase to
thiolactone peptide which is equivalent to acyl homoserine lactone of gram negative bacteria. General
pathways suggested for the quorum sensing inhibition by plant extracts focuses on such autoinducers.
Conclusion: Medicinal plants and plant extracts are the leading sources of quorum sensing inhibitors.
Patents related to quorum sensing inhibitors are taking new leaps in medicine, especially applications
relating to the addition of quorum sensing inhibitors on to the surface of implantable or indwelling devices
that are helpful in eradicating the trouble of infection in health care industry.
Keywords: Phytochemicals, quorum quenchers, QSI, autoinducer, acyl-homoserine lactone, AHLlactonase,
receptors, autoinducing peptide, thiolactone peptide, agrD, RNA III, plant extract, chromobacterium
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