Effects of Cinnamomum zeylanicum and Ocimum basilicum essential oils on the growth of Staphylococcus aureus ATCC 29213 and gene expression of enterotoxins A, C and E

Abstract

This study was conducted to determine the minimum inhibitory concentrations (MIC) of Cinnamomum zeylanicum and Ocimum basilicum essential oils on Staphylococcus aureus and assess their effects at sub MIC levels on the growth and production of enterotoxins A, C and E. EOs were obtained by hydrodistillation extraction using a Clevenger apparatus and characterized by gas chromatography/mass spectrometry. The MICs of EOs were found to be 1% and 0.2% (v/v) for cinnamon and basil, respectively. After incubation for 360 minutes at 35°C, 50% and 75% MIC of basil (B) and 75% MIC of cinnamon (C) EO decreased the growth rate of S. aureus significantly (p < 0.05). When cultured with EOs at 75% MIC, the transcriptional levels of the enterotoxin genes and the amount of enterotoxins secreted by S. aureus decreased significantly. The inhibitory effect of basil EO against S. aureus, both in growth and enterotoxin secretion, was higher than cinnamon (p < 0.05).

Keywords:

• Cinnamomum zeylanicum
• Ocimum basilicum
• essential oil
• Staphylococcus aureus
• enterotoxin
• gene expression

Acknowledgements

We are grateful to Dr. Andrew MacCabe of the Agrochemistry and Food Technology Institute (IATA), Valencia, Spain for critical reading of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work has been supported by the Amol University of Special Modern Technologies, Amol, Iran [grant number 8.2709].