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Volume 44, Number 2, April 2011

Screening of traditional Chinese medicinal plants for quorum-sensing inhibitors activity


Khee Hoon Koh, Foong-Yee Tham


Received: April 20, 2009    Revised: September 13, 2009    Accepted: October 29, 2009   

 

Corresponding author:

Department of Natural Sciences and Science Education, Nanyang Technological University, 1, Nanyang
Walk, Singapore 637616, Singapore.
E-mail address: foongyee.tham@nie.edu.sg (F.-Y. Tham).



 

Background and purpose: 

The misuse of antibiotics has contributed to widespread development of antimicrobial resistance among clinically significant bacterial species. Alternative approaches other than those using antibiotics are needed in the fight against infectious diseases. Quorum sensing (QS) is an intercellular signaling and gene regulatory mechanism, which is used by a number of opportunistic pathogenic bacteria in determining virulence gene expression. The study of QS may yield another strategy for disease control by interference with QS signals. Scientific research on complementary therapies such as traditional Chinese medicine (TCM) has focused mainly on its antibacterial properties. To test for anti-QS activity, 10 TCM herbs were screened using two biomonitor strains, Chromobacterium violaceum CV026 and Pseudomonas aeruginosa PA01. Interference with violacein (purple pigment) production in CV026 (exogenously supplied with homoserine lactone signals), and swarming in PA01, both QS-regulated phenomena, was used as indication of anti-QS activity. Eight of the selected TCM (80%) yielded QS inhibitors: Prunus armeniaca, Prunella vulgaris, Nelumbo nucifera, Panax notoginseng (root and flower), Punica granatum, Areca catechu, and Imperata cylindrica. Compounds that interfere with QS are present in TCM herbs and these medicines may be a rich source of compounds to combat pathogenic bacteria and reduce the development of antibiotic resistance.



 

Key words:

Medicinal plants, Quorum-sensing inhibitors, Traditional Chinese medicine