The antibacterial effects of Zanthoxylum limonella, Zanthoxylum bungeanum Maxim, and Zingiber montanum (J. Koenig) Link ex A. Dietr. essential oils and their combinations were tested against two bacterial strains including Staphylococcus aureus and Escherichia coli which are generally known for their implication on wound healing infections. The disc diffusion method with the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were employed to evaluate their antibacterial activity. The combined antibacterial effect of essential oils against the tested bacteria was evaluated by the checkerboard method and the fractional inhibitory concentration index (FICI) calculation. The results of the dissemination method demonstrated that all essential oils have antibacterial activity against tested bacteria with MIC and MBC ranging from 0.31-1.25 µg/mL and 0.62-5.00 µg/mL, respectively. The volatile compounds of Z. limonella, Z. bungeanum, and Z. montanum essential oils were analysed using gas chromatography-mass spectrometry. 1,8-Cineole and limonene were major compounds in the Z. limonella essential oil whereas 2,4-dimethylether-phloroacetophenone and terpinene-4-ol were major compounds in the Z. bungeanum and Z. montanum essential oils, respectively. The evaluation of the essential oils in combination revealed that the combination of Z. limonella and Z. montanum essential oils showed a synergistic effect against all tested bacteria. The synergistic effect of this combination could be resulted from major compounds in the combination such as 1,8-cineole, limonene, and terpinene-4-ol which were evaluated to possess strong antibacterial activity.
Audience Take Away Notes:
- Synergistic antibacterial effect is significantly detected in some mix essential oils.
- New products from mix essential oils may be extensively consumed.
- Mix essential oils may be applied in other applications due to its synergistic effect.