Ghaderi L, Moghimi R, Aliahmadi A, McClements DJ, Rafati H
Journal of Applied Microbiology, 2017
AIMS: Thymol rich medicinal plants have been used in traditional medicine to relieve infectious diseases. However, the application of essential oils as medicine is limited by its low water-solubility and high vapor pressure. The objective of this study was to produce stable nanoemulsions of Thymus daenensis oil in water by preventing Ostwald ripening and phase separation.
METHODS & RESULTS: The antibacterial activity of bulk and emulsified essential oil against selected pathogenic bacteria including Gram-negative (Haemophilus influenzae, Pseudomonas aeruginosa) and Gram-positive (Streptococcus pneumoniae) were investigated in the liquid and vapor phase. The optimum formulation (L2) contained 2% Tween 80 (surfactant) and 0.1% lecithin (co-surfactant) had a mean droplet diameter of 131 nm. In the liquid phase, the optimized nanoemulsion exhibited good antibacterial activity against Streptococcus pneumonia with MIC value of 0.0039 mg/mL. In the vapor phase, the MIC values against Streptococcus pneumonia were similar (<7.35 μL/L) for both bulk and emulsified essential oil. However, there was no antibacterial activity in the vapor phase against Haemophilus influenzae and Pseudomonas aeruginosa. Analysis of thymol concentration in the head-space indicated that the nanoemulsion retarded the release of thymol into the vapor phase.
CONCLUSIONS: These findings highlight the potential applications of nanoemulsions containing essential oils as antibacterial products.
SIGNIFICANCE AND IMPACT OF THE STUDY: The results of the current study highlight the advantages of nanoemulsification for improvement of the physicochemical properties and the antibacterial activity of Thymus daenensis EOs in the liquid and vapor phase for therapeutic purposes. This article is protected by copyright. All rights reserved.
Ghaderi L, Moghimi R, Aliahmadi A et al. Development of antimicrobial nanoemulsion-based delivery systems against selected pathogenic bacteria using a thymol rich Thymus daenensis essential oil. J Appl Microbiol. 2017 Jul 17. doi: 10.1111/jam.13541.