Down-regulatory effects of green coffee on pseudomonas aeruginosa lasi/lasr quorum-sensing system

Sepideh Benvari,1,* Hossein jamalifar,2

1. Department of Microbiology, Faculty of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran
2. Department of Drug and Food Control, Tehran University of Medical Sciences, Tehran, Iran



The lasi/lasr quorum sensing (qs) system plays an important role in pseudomonas aeruginosa pathogenicity and mechanism of aggression. inhibition of the qs system in p. aeruginosa can be a novel strategy for discovery of antimicrobials. green coffee extract (gce) is a good source of chlorogenic acid, a polyphenolic natural compound reported to possess antibacterial activity. the aim of this study is to evaluate the effect of gce on lasi/lasr expression in p. aeruginosa.


A total of 5 p. aeruginosa strains which were resistant to most of the commonly used antibiotics, were included. susceptibility to gce investigated through minimum inhibitory concentration (mic) and minimum bactericidal concentration (mbc). multiplex pcr was performed to detect lasi and lasr genes and the expression levels were quantified using real-time pcr method.


The mic and mbc values for gce ranged from 64 to 128 µg/ml. based on the result of multiplex pcr, lasi and lasr genes were detected in all strains. in the presence of gce, real-time pcr revealed a 2-fold and 1.5-fold decrease in the expression of lasi and lasr, respectively.


The data from this study support the notion that gce has a promising in vitro antibacterial effect against p. aeruginosa.


Green coffee, pseudomonas aeruginosa, quorum sensing