Quorum Sensing Inhibition in Pseudomonas aeruginosa PAO1 by Antagonistic Compound Phenylacetic Acid

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

“…The chemical compound PAA shows a structural similarity with the previously reported anti-QS compound salicylic acid (Bandara, Zhu, Sankaridurg, & Willcox, 2006;Yang et al, 2009;Yuan et al, 2007). Thus, based on this similarity, the inhibitory activity of PAA might be due to the inhibition of AHLregulated behaviors by binding competitively to the AHL receptor protein (Musthafa et al, 2012) (Fig. 1).…”

“…4) is an organic compound considered as a very active auxin (a type of plant hormone), which can be predominantly found in fruits. The capacity of this compound to interfere with QS has been recently reported due to its capacity for reducing the production of AHLdependent factors in P. aeruginosa PAO1 (pyocyanin, exopolysaccharide, and protease and elastase production) (Musthafa, Sivamaruthi, Pandian, & Ravi, 2012). In swimming inhibition assay, PAA-treated PAO1 cells exhibited poor motility in swimming agar plate, while in in vivo analysis, PAO1-preinfected C. elegans showed enhanced survival when treated with PAA.…”

In vitroantibiofilm activity ofMurraya koenigiiessential oil extracted using supercritical fluid CO2method againstPseudomonas aeruginosaPAO1

“…In this study, M. koenigii EO significantly inhibited the EPS production (86.85%) at a concentration of 0.3% v/v ( Figure S2). Similarly, Musthafa et al (2012) have reported significant reduction in the production of EPS to the level of 54% in P. aeruginosa PAO1 when treated with phenylacetic acid.…”

“…P. aeruginosa possesses notorious ability to produce a variety of toxins and extracellular enzymes which aid in pathogenesis. This includes virulence factors such as elastase, alkaline protease, exotoxin A and biofilm formation (Musthafa et al 2012). Biofilms are conglomerates of microbes enclosed in a self-secreted exopolymeric substance (EPS) (Vu et al 2009).…”

Beyond Traditional Antimicrobials: A Caenorhabditis elegans Model for Discovery of Novel Anti-infectives

“…Other natural inhibitors that have been tested for their anti-virulence effect in vivo using the C. elegans – P. aeruginosa infection model are the methanolic extract of Terminalia chebula fruit (Sarabhai et al, 2013), extract and active compound of Dalbergia trichocarpa bark (Rasamiravaka et al, 2015), tea polyphenols extracted from the leaf of Camellia sinensis L. (Yin et al, 2015), the methanolic extract of Trigonella foenum-graecum L. seed (Husain et al, 2015b), Syzygium aromaticum (clove) oil (Husain et al, 2013), and Mentha piperita (peppermint) oil (Husain et al, 2015a). In addition to targeting quorum sensing circuits, chemical compounds such as phenylacetic acid (Musthafa et al, 2012b), 2,5-piperazinedione (Musthafa et al, 2012a) and meta-bromo-thiolactone (O’Loughlin et al, 2013) as well as the hormonal therapy drug raloxifene (Ho Sui et al, 2012) inhibited P. aeruginosa pyocyanin production and reduced bacterial virulence in the nematode model. Other virulence determinants, including biofilm, proteases and elastase, as well as bacterial motility, were also suppressed by most of these molecules.…”