Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2015 Aug 11;10(8):e0135495.
doi: 10.1371/journal.pone.0135495. eCollection 2015.

Effect of Cinnamon Oil on Quorum Sensing-Controlled Virulence Factors and Biofilm Formation in Pseudomonas aeruginosa

Manmohit Kalia  1 , Vivek Kumar Yadav  1 , Pradeep Kumar Singh  1 , Deepmala Sharma  2 , Himanshu Pandey  3 , Shahid Suhail Narvi  4 , Vishnu Agarwal  1
Affiliations

Effect of Cinnamon Oil on Quorum Sensing-Controlled Virulence Factors and Biofilm Formation in Pseudomonas aeruginosa

Manmohit Kalia et al. PLoS One. .

Abstract

Quorum sensing (QS) is a system of stimuli and responses in bacterial cells governed by their population density, through which they regulate genes that control virulence factors and biofilm formation. Despite considerable research on QS and the discovery of new antibiotics, QS-controlled biofilm formation by microorganisms in clinical settings has remained a problem because of nascent drug resistance, which requires screening of diverse compounds for anti-QS activities. Cinnamon is a dietary phytochemical that is traditionally used to remedy digestive problems and assorted contagions, which suggests that cinnamon might contain chemicals that can hinder the QS process. To test this hypothesis, the anti-QS activity of cinnamon oil against P. aeruginosa was tested, measured by the inhibition of biofilm formation and other QS-associated phenomena, including virulence factors such as pyocyanin, rhamnolipid, protease, alginate production, and swarming activity. To this end, multiple microscopy analyses, including light, scanning electron and confocal microscopy, revealed the ability of cinnamon oil to inhibit P. aeruginosa PAO1 biofilms and their accompanying extracellular polymeric substances. This work is the first to demonstrate that cinnamon oil can influence various QS-based phenomena in P. aeruginosa PAO1, including biofilm formation.

PubMed Disclaimer

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Growth curves of P. aeruginosa PAO1 (1a), C. violaceum CV026 (1b) and E coli pJN105LpSC11 (1c) at a sub-lethal concentration of cinnamon oil, plotted with respect to the controls (no cinnamon oil).
Fig 2
Fig 2. QS inhibition of C. violaceum CV026 by cinnamon oil.
(a) The zone of inhibition with increasing concentrations of oil (a-control, b-0.1, c-0.2, d-0.4, e-0.6 μl/ml). (b) A decrease in violacein production was observed. The color change was measured at 590 nm. The error bars indicate the standard deviations of three measurements, and the data were normalized according to the OD600 of CV026.*, P<0.05 compared with the control. **, P<0.001 compared with the control.
Fig 3
Fig 3. Effects of different concentrations of cinnamon oil (control, 0.1, 0.2, 0.4, 0.6 μl/ml) on the concentration of 3-oxo-C12HSL produced by P. aeruginosa PAO1grown up to 24h.
Fig 4
Fig 4. Effects of different concentration (0.1–0.6 μl/ml) of cinnamon oil on the production of pyocyanin.
Error bars indicate the standard deviations for three measurements, and the data were normalized according to the OD600.*, P<0.05 compared with the control.
Fig 5
Fig 5. Swarming motility of P. aeruginosa PAO1.
(a) Untreated (b) treated with 0.2 μl/ml cinnamon oil.
Fig 6
Fig 6. Effect of cinnamon oil on the production of alginate by P. aeruginosa PAO1.
Error bars indicate the standard deviation of three measurements, and the data were normalized according to the OD600.**, P<0.001 compared with the control.***,P<0.0001 compared with the control.
Fig 7
Fig 7
(a) Detection of the inhibition of protease production by cinnamon oil on skimmed milk agar plates (a-control, b-0.1, c-0.2, d-0.4, e-0.6 μl/ml). (b) Effects of different concentrations of cinnamon oil on the production of protease. Error bars indicate the standard deviations of three measurements, and the data were normalized according to the OD600. **, P<0.001 compared with the control. *** P<0.0001 compared with the control.
Fig 8
Fig 8. Quantification of PAO1 biofilms in the presence of various concentrations of cinnamon oil.
The biofilms were quantified after 24 h of incubation and are represented as adhesion units (OD590/OD600). The error bars indicate the standard deviations of three measurements, and the data were normalized according to the OD600. ***, P<0.0001 compared with the control. ****, P<0.00001 compared with the control.
Fig 9
Fig 9. Microscopy images of P. aeruginosa PAO1 biofilms that formed with (right) 0.8 μl/ml and without (left) cinnamon oil.
Scanning electron microscopy (a-b) and light microscopy images (c-d). Inhibition of GFP-PAO1 biofilm formation (e-f). Significant reduction in the DNA content of the GFP-PAO1 biofilm (g-h). Overlay of (e-f, g-h) images displaying the reduction in extracellular DNA associated with the GFP-PAO1 biofilm (i-j). In the image (i), extracellular DNA is indicated with an arrowhead. A reduction in EPS production was observed after staining P. aeruginosa PAO1 with FITC-conA. This effect is evident from the scattered appearance of the cells in the treated samples (k-l).
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Fuqua WC, Winans SC, Greenberg EP. Quorum sensing in bacteria: the Lux R- Lux I family of cell density—responsive transcriptional regulators. J Bacterol. 1994; 176:269–275. - PMC - PubMed
    1. Rutherford ST, Bassler BL. Bacterial Quorum Sensing: its role in virulence and possibilties of its control. Cold Spring Harbor Prespect Med. 2012; 2(11): a012427. - PMC - PubMed
    1. Christopher M, Bassler W, Bassler LB. Quorum Sensing: Cell- to- Cel Communication in Bacteria. Annu Rev Cell Dev Biol. 2005; 21:319–346. - PubMed
    1. Lyczak JB, Cannon CL, Pier GB. Lung infections associated with cystic fibrosis. Clin Microbiol Rev. 2002;15:194–222. - PMC - PubMed
    1. Parsek MR,Val DL, Hanzelka BL, Cronan JE, Greenberg EP. Acyl homoserine lactone quorum sensing signal generation. Proc Natl Acad Sci. 1999;96: 4360–4365. - PMC - PubMed

Publication types

MeSH terms

Grants and funding

The Department of Science and Technology and Department of Biotechnology, Government of India, and TEQIP-II are acknowledged for research funding and fellowship for enabling this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

LinkOut - more resources