Protocol for determining minimum inhibitory concentrations of essential oils against bacterial pathogens using broth...

Area of Science:

• Microbiology
• Natural Products Chemistry
• Pharmacology

Background:

• Essential oils (EOs) show significant antimicrobial potential.
• Lack of a standardized assay hinders comparability of minimum inhibitory concentration (MIC) data for EOs.
• Harmonized methods are crucial for reproducible antimicrobial research.

Purpose of the Study:

• To establish a reproducible and harmonized protocol for determining the MIC of EOs against aerobic bacterial pathogens.
• To enable cross-study comparability of antimicrobial activity data for essential oils.
• To provide a detailed method for essential oil broth microdilution assays.

Main Methods:

• Broth microdilution technique using Tween 80 for EO dispersion.
• Preparation of standardized bacterial inoculum.
• Two-fold serial dilution of EOs in 96-well plates.
• Visual determination of the minimum inhibitory concentration (MIC) endpoint.

Main Results:

• A detailed protocol for MIC determination of essential oils is presented.
• The method addresses challenges in EO dispersion and inoculum standardization.
• The protocol facilitates consistent MIC endpoint determination.

Conclusions:

• The presented protocol offers a standardized approach for evaluating the antimicrobial activity of essential oils.
• This method will improve the reliability and comparability of MIC data in essential oil research.
• Adoption of this protocol can advance the scientific understanding of essential oil antimicrobial properties.