Essential Oils

Réné-Maurice Gattefossé is renowned as creating the modern discipline of the therapeutic application of essential oils with the publication of his seminal work Aromatherapie: Les Huiles essentielles, hormones végétales in 1937 in which he introduced the word “aromatherapy”.  However the use of essential oils dates back several millennia.  Mesopotamian distillation pots found at Tepe Gawra with traces of cedar wood oil show that Egyptians, specifically Mesopotamians, were distilling and using essential oils at least as far back as 3,500 BC. The use of aromatic plants in medicine and personal care is as old as humanity itself.

At Oxford Biosciences we have particular expertise in essential oil science and keep up to date with current research on uses, safety, and new distillations regularly presenting at and attending conferences in Europe and North America, and visiting farms and distillers worldwide.

wild-tisserand-smith2007aIn addition to the 26 allergens found in many essential oils which must be listed on product labels, Cosmetics Europe have placed restrictions on a few natural constituents of some essential oils.  Methyl eugenol, bergapten and carvone are a few examples.

Methyl eugenol

Commonly used essential oils that contain methyl eugenol include Rosa damascena (<3.5%, Rose), Laurus nobilis (⩽9%, Bay laurel), Myrtus communis (⩽1, Green myrtle), Cinnamomum camphora (⩽1%, Camphor), Salvia sclarea (⩽2%, Clary sage), Ocimum sanctum, Ocimum tenuiflorum (20%, Holy basil, Tulsi) and Melissa officinalis (⩽1%, Lemon balm). This list is certainly not exhaustive. Analyses of these oils from different countries indicate that an overall ban, or overall acceptance, of essential oils from varying species is not justifiable, apart from chemotypes or species that always contain very high quantities of methyl eugenol.

Natural variation, chemotypes (often poorly identified), cultivars, and the country of origin all have an important influence on essential oil chemistry. For example, both West Indian bay and rose are mentioned in the IFRA list as containing <15% and <3.5%, respectively. Some samples of rose oil contain no methyl eugenol whilst the content in bay can be as low as 0.3%. Depending on the quantity used, different samples may or may not breach the IFRA restriction.

Although inaccurate, it is commonplace to measure essential oils in drops. If the assumption is made that it is roughly 20-25 drops to a millilitre, then each drop would constitute approximately 33 mg. Blended within a base oil, if the entire quantity were to be used in a massage, then just one drop of an essential oil containing 0.5% methyl eugenol would be greater than the daily IFRA restriction of 150 μg.

Therefore, whenever possible, it is advisable to get a GC/MS analysis from your supplier for each essential oil you intend to use in your products.