Antiviral efficacy and mechanisms of action of oregano essential oil and its primary component carvacrol against murine norovirus

D. H. Gilling, M. Kitajima, J. R. Torrey, Kelly R Bright

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Aims: To investigate the antiviral efficacy of oregano oil and its primary active component, carvacrol, against the nonenveloped murine norovirus (MNV), a human norovirus surrogate. Methods and Results: Along with an observed loss in cell culture infectivity, the antiviral mechanisms of action were determined in side-by-side experiments including a cell-binding assay, an RNase I protection assay and transmission electron microscopy (TEM). Both antimicrobials produced statistically significant reductions (P ≤ 0·05) in virus infectivity within 15 min of exposure (c. 1·0-log10). Despite this, the MNV infectivity remained stable with increasing time exposure to oregano oil (1·07-log10 after 24 h), while carvacrol was far more effective, producing up to 3·87-log10 reductions within 1 h. Based on the RNase I protection assay, both antimicrobials appeared to act directly upon the virus capsid and subsequently the RNA. Under TEM, the capsids enlarged from ≤35 nm in diameter to up to 75 nm following treatment with oregano oil and up to 800 nm with carvacrol; with greater expansion, capsid disintegration could be observed. Virus adsorption to host cells did not appear to be affected by either antimicrobial. Conclusions: Our results demonstrate that carvacrol is effective in inactivating MNV within 1 h of exposure by acting directly on the viral capsid and subsequently the RNA. Significance and Impact of the Study: This study provides novel findings on the antiviral properties of oregano oil and carvacrol against MNV and demonstrates the potential of carvacrol as a natural food and surface (fomite) sanitizer to control human norovirus.

Original languageEnglish (US)
Pages (from-to)1149-1163
Number of pages15
JournalJournal of Applied Microbiology
Volume116
Issue number5
DOIs
StatePublished - 2014

Fingerprint

Origanum
Norovirus
Volatile Oils
Antiviral Agents
Capsid
Oils
Pancreatic Ribonuclease
Viruses
Transmission Electron Microscopy
Fomites
RNA
Adsorption
carvacrol
Cell Culture Techniques
Food

Keywords

  • Human norovirus
  • Mechanism of action
  • Nonenveloped viruses
  • Plant antimicrobials
  • Sanitizer

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Biotechnology
  • Medicine(all)

Cite this

Antiviral efficacy and mechanisms of action of oregano essential oil and its primary component carvacrol against murine norovirus. / Gilling, D. H.; Kitajima, M.; Torrey, J. R.; Bright, Kelly R.

In: Journal of Applied Microbiology, Vol. 116, No. 5, 2014, p. 1149-1163.

Research output: Contribution to journalArticle

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