Detecting traces of methyl eugenol in essential oils: tea tree oil, a case study

Abstract

Methyl eugenol is a naturally occurring flavour and fragrance found in a variety of different food sources, including spices, herbs and fruit and also as a component of natural essential oils. Commonly used oils with more than 0.1% of methyl eugenol include calamus, rosewood, elemi, ylang ylang, cymbopogon, star anise, lovage, verbena, nutmeg, basil, pimento, bay leaf, rose and clove. In addition there are other potential sources of exposure to methyl eugenol, including agriculture, wine consumption and ambient background in air and water. Because high doses of some allyl alkoxybenzenes have induced tumours in rats and mice, use is recommended as either restricted or, in the case of safrole, prohibited. Many reviewers and researchers present clear evidence that these restrictions are excessive, especially those who accept that carcinogenesis is a threshold phenomenon. This paper describes suitable gas chromatographic methods for the determination of trace amounts of methyl eugenol in the essential oil of tea tree, Melaleuca alternifolia, terpinen-4-ol type. Published 'trace' amounts were interpreted as being as high as 0.3-0.9% by one regulator. Peak assignment by GC-MS and co-elution with a standard facilitated the GC-FID determination of 128 commercial samples. Inter-laboratory confirmation was achieved using GC-MS with selected ion monitoring. These determinations indicated that the methyl eugenol content of tea tree oil ranged from less than 0.01% to 0.06% (mean 0.02%), i.e. 20-fold lower than the regulator's interpretation and one million times lower than the logarithmic scale levels known to cause carcinomas in rats.

Electrochemical Oxidation of Fragrances 4-Allyl and 4-Propenylbenzenes on Platinum and Carbon Paste Electrodes

“…[1][2][3][4][5] Fragrances that are air-sensitive may form peroxides, respiratory irritants, and aerosol particles that cause inflammatory responses in the lungs. The photochemistry of some allylic compounds such as cis-trans isoeugenol and citral, were oxidized in the presence of atmospheric oxygen or photosensitized species (O 3 , OH, NO 3 , etc.). [6][7][8] However, most reports have focused on the photochemical reaction of eugenol derivatives to for the synthesis of new flavors chemicals.…”

Chemical Composition and Antibacterial Activity of Melaleuca bracteata Essential Oil from India: A Natural Source of Methyl Eugenol

“…Most of the industrial uses of the methyl eugenol, as flavor or fragrance, meet out by synthetic route. [7,8,[20][21][22][23][24][25]. In spite of these natural sources, most of the commercial product utilizes synthetic methyl eugenol.…”

Conversion of eugenol to methyleugenol: Computational study and experimental

“…Methyleugenol is a component of some essential oils are usually used in massage oil and alternative medicines, also as a agent of food flavor in jellies, baked goods, chewing gum, candy, pudding, relish, and ice cream [3]. Other benefits used as aromatherapy, fragrance in the perfume [4], cosmetics [5], toiletries and detergents [6]. Methyleugenol has been used as an anesthetic [7] even as towing insects in combination with insecticides [8].…”