The Antibacterial Activity of 17 Essential Oils against Escherichia coli

Abstract

Purpose: The purpose of this study was to investigate the effects of 17 essential oils (EOs) on Escherichia coli (E. coli), including their antibacterial activity according to the concentration used and its extraction site.Methods: All 17 EOs were prepared by step dilution at concentrations of 0.5% (v/v) and 1% (v/v). EOs were dispensed into 96-well plates with bacterial culture aliquots and incubated for 18 h; then, their absorbance was measured using a microplate reader.Results: Culture absorbance showed that thyme white (TM), palmarosa (PR) and rosemary verbenone (RM) at concentrations of 0.5% (v/v) and 1% (v/v) showed high antibacterial activity, similar to that of ampicillin. Melisa true (MS), RM, PR, lavender Bulgarian (LV), lemon (LM), peppermint premium (PM) and eucalyptus bluegum (EC) also showed increased antibacterial activity in a concentration-dependent manner. Finally, TM, MS, RM, PR, and lemongrass (LG) extracted from leaves showed higher antibacterial activity than extracts from other organs.Conclusion: TM extracted from leaves showed an excellent antibacterial effect; it exhibited bacterial growth at the same level of ampicillin. It is a natural substance that suppresses the action of bacteria in the inflammatory reaction of the skin and that may be used as a raw material for customized cosmetics.