Extracts of Cordia gilletii de wild (Boraginaceae) quench the quorum sensing of Pseudomonas aeruginosa PAO1

Aim: The fight against infectious diseases and antimicrobial resistances needs the exploration of new active compounds with new proprieties such as disrupting quorum sensing (QS) mechanisms, which is a cell-to-cell communication that regulates bacterial virulence factors. In this work, leaves and root barks extracts of a Congolese medicinal plant, Cordia gilletii, were investigated for their effect on the production of Pseudomonas aeruginosa major virulence factors regulated by QS. Material and methods: The effect of Cordia gilletii extracts on virulence factors of Pseudomonas aeruginosa PAO1 was studied by the evaluation of the production of pyocyanine, elastase and biofilm; and by the measurement of the expression of QS-related genes. Results: The dichloromethane extract from root barks was found to quench the production of pyocyanin, a QS-dependent virulence factor in P. aeruginosa PAO1. Moreover, this extract specifically inhibits the expression of several QS-regulated genes (i.e. lasB, rhlA, lasI, lasR, rhlI and rhlR) and reduces biofilm formation by PAO1. Conclusion: This study contributes to explain the efficacy of Cordia gilletii in the traditional treatment of infectious diseases caused by P. aeruginosa.