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

Abstract

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.

Exploiting Quorum Sensing To Confuse Bacterial Pathogens

“…Extracts of fruits (e.g., blackberries, cranberries, vanilla, and citrus) and herbs (e.g., rosemary and turmeric) and extracts and oils of other plant materials (garlic, clove, and cinnamon) and medicinal plants (e.g., betel nut and notoginsing) have all displayed QSI activity to some degree, typically found via inhibition of violacein production in the C. violaceum bioassay (137,138,(264)(265)(266)(267)(268)(269)(270)(271)(272)(273)(274)(275). In very few cases, however, have individual compounds been isolated or identified from these kinds of complex sources.…”

Anti-quorum sensing and antimicrobial activities of some traditional Chinese medicinal plants commonly used in South-East Asia

“…This contrast suggests that the anti-QS activity of TCM on bacteria may be more ubiquitous and diverse than previously thought and that there is distinct potential for further work on other TCM species in this area of research. Indeed, in a recent preliminary screen, seven out of 10 plants (70%) used commonly in TCM were shown to have QSI properties (Koh and Tham, 2011).…”

“…Much less attention has been given to its other possible anti-pathogenic properties. The inhibition of quorum sensing (QS), or bacterial cell-tocell communication, is one example of an anti-pathogenic effect of TCM that has been less investigated (Koh and Tham, 2011).…”

“…Most recently, there has also been indication that herbs used in TCM have QSI properties and could be targeted for further screening (Koh and Tham, 2011). As QSI does not kill or inhibit bacteria growth, QSI drugs that interfere with signaling may have an advantage because they do not impose strong selective pressure for development of resistance, as would antibiotics (Rasmussen and Givskov, 2006).…”

Plant food extracts and phytochemicals: Their role as Quorum Sensing Inhibitors

“…Although the capacity of pomegranate as QSI has received much less attention, some papers have already demonstrated the anti-QS capacity of pomegranate using the biosensor strain C. violaceum (Koh & Tham, 2011;Truchado, Gil, et al, 2012). Additionally, the ability of pomegranate to inhibit the AHL system of pathogenic bacteria such as Yersinia enterocolitica and Erwinia carotovora has been evidenced.…”