Antimicrobial Activity of Ternary Essential Oil Mixtures in Topical Cosmetic Preparations Against Acne Vulgaris-Associated Bacteria.

Date
2017
Authors
Owen, Lucy
Grootveld, M.
Arroo, R. R. J.
Ruiz-Rodado, Victor
Price, Penny
Laird, Katie
Journal Title
Journal ISSN
ISSN
DOI
Volume Title
Publisher
Phytochemical Society of Europe
Peer reviewed
Yes
Abstract
Acne vulgaris is a chronic skin condition associated with overgrowth of Propionibacterium acnes and Staphylococcus epidermidis. Antibiotics are commonly prescribed to control acne; however, resistance has emerged, indicating the need for new antimicrobial therapies1. Several essential oils (EOs) are antimicrobial, including against antibiotic-resistant isolates, indicating that antimicrobial formulations may be developed using EOs2. The aim of this study was to develop a topical preparation incorporating EOs to control acne-associated bacteria, and compare its efficacy with the topical antibiotic formulations Dalacin T® and Stiemycin®. The antimicrobial activity of litsea (Litsea cubeba), rosewood (Aniba rosaeadora) and clove bud (Syzigum aromaticum) EOs was identified using the Kirby-Bauer disc diffusion method3 and the minimum inhibitory concentrations (MICs) were determined using a broth microdilution assay3.The MICs of clove bud and rosewood were 1.38 mg/ml against S. epidermidis and P. acnes. The MIC of litsea was 1.11 mg/mL against S. epidermidis and 2.23 mg/mL against P. acnes. The antimicrobial activity of a ternary combination of these EOs was further investigated using the checkerboard method with calculation of fractional inhibitory concentration index (FICI)4. Synergy was observed against both test species (FICI < 0.5). The EOs were characterised by both GC-MS and NMR. The antimicrobial efficacy of a cosmetic preparation containing the ternary EO combination was then compared to that of the current prescription medicines Dalacin T® and Stiemycin®. A combination of 0.53 mg/mL litsea, 0.11 mg/mL rosewood and 0.11 mg/mL clove bud EOs was formulated into a neroli herbal distillate with 0.5% (v/v) ethanol. Survival of P. acnes and S. epidermidis (types and clinical isolates) after a 24 h contact with the formulations was determined and compared to Dalacin T® and Stiemycin®. The formulation completely inhibited P. acnes (7 log10 reduction) and S. epidermidis (6 log10 reduction), and was equivalent in activity to Dalacin T® and Stiemycin®, including erythromycin-resistant isolates. The EO combination alone was either more antimicrobial (p ≤ 0.05) or equivalent in activity to the active ingredients of Dalacin T® and Stiemycin® (10 mg/mL clindamycin phosphate and 20 mg/mL erythromycin, respectively). The formulation may be useful as an alternative to antibiotic preparations for the control of acne-associated bacteria.
Description
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Citation
Owen, L. et al. (2017) Antimicrobial activity of ternary essential oil mixtures in topical cosmetic preparations against acne vulgaris-associated bacteria. Phytochemical Society of Europe Meeting.
Research Institute
Leicester Institute for Pharmaceutical Innovation - From Molecules to Practice (LIPI)