Cyanidin inhibits quorum signalling pathway of a food borne opportunistic pathogen

Dai

et al. 2016

Sci Rep

An ethyl acetate (EtOAc) extract isolated from the marine bacterium, Rheinheimera aquimaris QSI02, was found to exhibit anti-quorum sensing (anti-QS) activity. A subsequent bioassay-guided isolation protocol led to the detection of an active diketopiperazine factor, cyclo(Trp-Ser). Biosensor assay data showed that the minimum inhibitory concentration (MIC) of cyclo(Trp-Ser) ranged from 3.2 mg/ml to 6.4 mg/m for several microorganisms, including Escherichia coli, Chromobacterium violaceum CV026, Pseudomonas aeruginosa PA01, Staphylococcus aureus, and Candida albicans. Additionally, sub-MICs of cyclo(Trp-Ser) decreased the QS-regulated violacein production in C. violaceum CV026 by 67%. Furthermore, cyclo(Trp-Ser) can decrease QS-regulated pyocyanin production, elastase activity and biofilm formation in P. aeruginosa PA01 by 65%, 40% and 59.9%, respectively. Molecular docking results revealed that cyclo(Trp-Ser) binds to CviR receptor more rigidly than C6HSL with lower docking energy −8.68 kcal/mol, while with higher binding energy of −8.40 kcal/mol than 3-oxo-C12HSL in LasR receptor. Molecular dynamics simulation suggested that cyclo(Trp-Ser) is more easy to bind to CviR receptor than natural signaling molecule, but opposite in LasR receptor. These results suggest that cyclo(Trp-Ser) can be used as a potential inhibitor to control QS systems of C. violaceum and P. aeruginosa and provide increased the understanding of molecular mechanism that influences QS-regulated behaviors.

Section: Discussionmentioning

confidence: 99%

A diketopiperazine factor from Rheinheimera aquimaris QSI02 exhibits anti-quorum sensing activity

Dai

et al. 2016

Sci Rep

“…The light microscopic analysis method described for biofilm formation on a glass cover slip was performed as described previously. 36 Briefly, the C. violaceum (CV12472) isolate was added to the fresh LB medium (supplemented with 0.2% (w/v) glucose) containing glass cover slips using a 6-well flat bottom microtitre plate with EA fruit extracts and along with appropriate control wells without the extracts. The plate was incubated in a static condition at 30 °C for 24 h. After incubation, the unbound planktonic cells from both treated and untreated glass cover slips were removed, rinsed with sterile distilled water, and stained with 0.2% crystal violet.…”

Section: Methodsmentioning

confidence: 99%

Inhibition of Quorum Sensing and Biofilm Formation in Chromobacterium violaceum by Fruit Extracts of Passiflora edulis

et al. 2020

Chromobacterium violaceum ( C. violaceum ) is a Gram-negative, rod-shaped facultatively anaerobic bacterium implicated with recalcitrant human infections. Here, we evaluated the anti-QS and antibiofilm activities of ethyl acetate extracts of Passiflora edulis ( P. edulis ) on the likely inactivation of acyl-homoserine lactone (AHL)-regulated molecules in C. violaceum both by in vitro and in silico analyses. Our investigations showed that the sub-MIC levels were 2, 1, and 0.5 mg/mL, and the concentrations showed a marked reduction in violacein pigment production by 75.8, 64.6, and 35.2%. AHL quantification showed 72.5, 52.2, and 35.9% inhibitions, inhibitions of EPS production (72.8, 36.5, and 25.9%), and reductions in biofilm formation (90.7, 69.4, and 51.8%) as compared to a control. Light microscopy and CLSM analysis revealed dramatic reduction in the treated biofilm group as compared to the control. GC–MS analysis showed 20 major peaks whose chemical structures were docked as the CviR ligand. The highest docking score was observed for hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester bonds in the active site of CviR with a binding energy of −8.825 kcal/mol. Together, we found that hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester remarkably interacted with CviR to inhibit the QS system. Hence, we concluded that hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester of P. edulis could likely be evaluated for treating C. violaceum infections.

“…Gopu and Shetty reported that the naturally occurring anthocyanin-cyanidin significantly inhibited QS-dependent phenotypes such as biofilm formation (72.43%), violacein production (73.96%), and EPS production (68.65%) in the opportunistic pathogen Klebsiella pneumoniae in a concentration-dependent manner. [ 47 ] Rosmarinic acid extracted from sweet basil bound to the QS-regulator RhlR of P. aeruginosa PAO1 and competed with the bacterial ligand N -butanoyl-homoserine lactone (C4-HSL). Furthermore, it stimulated a greater increase in RhlR-mediated transcription in vitro than that of C4-HSL.…”

Section: P Hytochemicals As Q Uorum mentioning

confidence: 99%

Anti-quorum sensing natural compounds

Asfour

2018

J Microsc Ultrastruct

235

109

Increasing extent of pathogenic resistance to drugs has encouraged the seeking for new anti-virulence drugs. Many pharmacological and pharmacognostical researches are performed to identify new drugs or discover new structures for the development of novel therapeutic agents in the antibiotic treatments. Although many phytochemicals show prominent antimicrobial activity, their power lies in their anti-virulence properties. Quorum sensing (QS) is a bacterial intercellular communication mechanism, which depends on bacterial cell population density and controls the pathogenesis of many organisms by regulating gene expression, including virulence determinants. QS has become an attractive target for the development of novel anti-infective agents that do not rely on the use of antibiotics. Anti-QS compounds are known to have the ability to prohibit bacterial pathogenicity. Medicinal plants offer an attractive repertoire of phytochemicals with novel microbial disease-controlling potential, due to the spectrum of secondary metabolites present in extracts, which include phenolics, quinones, flavonoids, alkaloids, terpenoids, and polyacetylenes. They have recently received considerable attention as a new source of safe and effective QS inhibitory substances. The objective of this review is to give a brief account of the research reports on the plants and natural compounds with anti-QS potential.