title: Anti-quorum sensing activity of the traditional Chinese herb, Phyllanthus amarus.
abstract: The discovery of quorum sensing in Proteobacteria and its function in regulating virulence determinants makes it an attractive alternative towards attenuation of bacterial pathogens. In this study, crude extracts of Phyllanthus amarus Schumach. & Thonn, a traditional Chinese herb, were screened for their anti-quorum sensing properties through a series of bioassays. Only the methanolic extract of P. amarus exhibited anti-quorum sensing activity, whereby it interrupted the ability of Chromobacterium violaceum CVO26 to response towards exogenously supplied N-hexanoylhomoserine lactone and the extract reduced bioluminescence in E. coli [pSB401] and E. coli [pSB1075]. In addition to this, methanolic extract of P. amarus significantly inhibited selected quorum sensing-regulated virulence determinants of Pseudomonas aeruginosa PA01. Increasing concentrations of the methanolic extracts of P. amarus reduced swarming motility, pyocyanin production and P. aeruginosa PA01 lecA::lux expression. Our data suggest that P. amarus could be useful for attenuating pathogens and hence, more local traditional herbs should be screened for its anti-quorum sensing properties as their active compounds may serve as promising anti-pathogenic drugs.
authors.affiliation: Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia. kokgan@um.edu.my.
authors.forename: Kumutha
authors.initials: K
authors.lastname: Priya
authors.forename: Wai-Fong
authors.initials: WF
authors.lastname: Yin
authors.forename: Kok-Gan
authors.initials: KG
authors.lastname: Chan
mesh_terms: D018829:Adhesins, Bacterial / Q000032:analysis / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001681:Biological Assay; D049109:Cell Proliferation / Q000187:drug effects; D002861:Chromobacterium / Q000187:drug effects; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D000432:Methanol; D029803:Phyllanthus / Q000737:chemistry*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D011710:Pyocyanine / Q000032:analysis / Q000378:metabolism; D053038:Quorum Sensing / Q000187:drug effects*
chemical_list: D018829:Adhesins, Bacterial; D000900:Anti-Bacterial Agents; D004365:Drugs, Chinese Herbal; C102929:LecA protein, bacteria; D011710:Pyocyanine; D000432:Methanol