9.
Edgar Selvaag, Jan
Řivind Holm & Per Thune (1995) "Allergic Contact Dermatitis in an
Aroma Therapist with Multiple Sensitisations to Essential Oils" Contact
Dermatitis 33, 354-5.
The authors don’t make a good start to this article when they state: "essential oils consist of terpenes, hydrocarbons with the general formula C10H16, related structurally to cymol (methyl-isopropyl-benzol)".
This is not a scientifically correct statement.
para-Cymol is the old discarded non-systematic name for para-cymene, which is an aromatic hydrocarbon, not a monoterpene hydrocarbon. Under IUPAC guidelines compounds which end in "- ol" are nowadays termed alcohols, and so the name "cymol" should not really be used, as it is confusing. It is inaccurate to say that C10 H16 hydrocarbons relate to para-cymene (4-isopropyltoluene) – which incidentally structurally is C10H14, not C10H16 as stated - although many monocyclic monoterpene hydrocarbons may possess a para-menthane skeleton. It is also arguable that in any case, the occurrence of para-cymene in essential oils is purely as an artefact from the oxidation or re-arrangement of monoterpene hydrocarbons such as a -terpinene or g -terpinene.
A better and more factually accurate introduction might have been to say that "essential oils consist of complex mixtures of mono- and sesqui-terpene hydrocarbons, and oxygenated materials biogenically derived from them. Other common essential oil constituents include phenyl propanoids from the Shikimic acid pathway, and their biotransformation products, and other compounds from the metabolism of fatty acids and amino acids."
The article goes on to describe the patch test results to twenty applied essential oils (no botanical names, chemotypes or geographic origins mentioned in the article) tested at 1% and 5% in petrolatum. This resulted in the authors reporting seventeen positive results out of twenty. The authors speculate that a developed multiple sensitivity to essential oils, and chronic hand eczema associated with handling household cleaners, sealing wax and paints, was originally caused by sensitivity following exposure to lemongrass oil.
Copyright © 2002 by Tony Burfield. All Rights Reserved.