Inhibitory Effect of Five Naturally Occurring Compounds on the Expression of Genes Associated with the QS System and some Virulence Factors in P. aeruginosa

Abstract

Pseudomonas aeruginosa is an opportunistic nosocomial pathogen with a pathogenicity that is an important factor in public health and is the result of the functioning of the Quorum Sensing (QS) system. Currently, compounds of natural origin have shown promising biological effects on certain pathogens in recent years. The aim of the present study was to determine the possible inhibitory effect of five naturally occurring molecules on some genes associated with two pathways of the QS system, as well as on elastase protease and pyocyanin production in two resistant strains of P. aeruginosa. For this purpose, RT-qPCR assays were performed to know the expression of some QS-associated genes (lasR, rhlR, lasI, aprA and lasB) and spectrophotometric assays to evaluate the production of elastase, protease and pyocyanin in the presence or absence of the molecules. It was found that sesamin and ferulic acid were the molecules with the highest inhibitory effect, higher than 40 %, on most of the genes evaluated (lasR, rhlR, aprA and lasB) in the two P. aeruginosa strains BAA-47 and 27853. Likewise, ferulic acid was the most active compound on two of the three virulence factors evaluated even though in general the effect of the molecules was not greater than 50 %. Therefore, these compounds are considered to have a possible multitarget effect by inhibiting the expression of genes associated with the two main systems of P. aeruginosa.

Keywords:
Quorum sensing; Pseudomonas aeruginosa; virulence; natural compounds

HIGHLIGHTS

Sesamin and ferulic acid had the highest inhibitory effect on the genes evaluated in P. aeruginosa

These compounds have a possible multitarget effect on the two main systems of QS in P. aeruginosa.

Ferulic acid was the most active compound on two of the three virulence factors evaluated

GRAPHICAL ABSTRACT