Antibacterial mode of action of Cinnamomum verum bark essential oil, alone and in combination with piperacillin, against a multi-drug-resistant Escherichia coli strain

Polly Soo Xi Yap, Thiba Krishnan, Kok Gan Chan, Swee Hua Erin Lim

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45 Citations (Scopus)

Abstract

This study aims to investigate the mechanism of action of the cinnamon bark essential oil (CB), when used singly and also in combination with piperacillin, for its antimicrobial and synergistic activity against beta-lactamase TEM-1 plasmid-conferred Escherichia coli J53 R1. Viable count of bacteria for this combination of essential oil and antibiotic showed a complete killing profile at 20 h and further confirmed its synergistic effect by reducing the bacteria cell numbers. Analysis on the stability of treated cultures for cell membrane permeability by CB when tested against sodium dodecyl sulfate revealed that the bacterial cell membrane was disrupted by the essential oil. Scanning electron microscopy observation and bacterial surface charge measurement also revealed that CB causes irreversible membrane damage and reduces the bacterial surface charge. In addition, bioluminescence expression of Escherichia coli [pSB1075] and E. coli [pSB401] by CB showed reduction, indicating the possibility of the presence of quorum sensing (QS) inhibitors. Gas-chromatography and mass spectrometry of the essential oil of Cinnamomum verum showed that trans-cinnamaldehyde (72.81%), benzyl alcohol (12.5%), and eugenol (6.57%) were the major components in the essential oil. From this study, CB has the potential to reverse E. coli J53 R1 resistance to piperacillin through two pathways; modification in the permeability of the outer membrane or bacterial QS inhibition.

Original languageEnglish
Pages (from-to)1299-1306
Number of pages8
JournalJournal of Microbiology and Biotechnology
Volume25
Issue number8
DOIs
Publication statusPublished - 2015
Externally publishedYes

Keywords

  • Antibacterial activity
  • Chemical composition
  • Cinnamomum verum
  • Essential oil
  • Membrane permeability
  • Quorum sensing

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