and therefore (to some!) ‘valueless’ terpenes. The terpenes limonene and alpha-pinene, for example, oxidize readily and this alters their composition, resulting in changes to the aroma and to the therapeutic effects. This tendency of some constituents to oxidize makes storage of certain oils rather difficult. Also, having only slight solubility in alcohol, they give a cloudy appearance to the end product – a drawback to the perfumer and flavourist. De-terpenated essential oils are therefore ‘more soluble, more stable and much stronger in odour’.8a
Terpeneless oils are not recommended for use in aromatherapy, because not only is the wholeness (and therefore the natural synergy) of the oil destroyed, but it now contains a higher percentage of the other chemical components; some of these may be the more powerful ones with which an aromatherapist has to take care even when present in lesser quantities in a whole oil!
Terpenes are removed by distilling under reduced pressure; as these are the smallest molecules present in essential oils they are the first to evaporate, eventually leaving the terpene-free oil in the distilling flask.
2. Folded Essential Oils
These are concentrated oils, differing from terpeneless oils in that they still contain varying amounts of terpenes. The process is halted wherever the perfumer wishes, with varying, known, percentages of terpenes being removed. The oils are referred to as singlefold, twofold – up to fivefold (where the greatest percentage of terpenes have been removed).8b
Essential oils are fractionated to remove other constituents too, e.g. bergapten (or bergaptene) which is a furocoumarin, not a terpene (see chapter 3). Fractionated oils are of use only in perfumery and the food industry, although some aromatherapists use bergapten-free bergamot oil because bergapten is the chemical responsible for photo-sensitization (yet use in sunlight is its only contra-indication! – see chapter 6). In my opinion this goes against the basic belief in aromatherapy that the whole, natural, synergistic mix of components, as extracted from the plant, should be used for maximum therapeutic benefit.
Rectification
Rectification (‘putting right’, or ‘cleaning up’) is carried out by redistilling an essential oil which either has been contaminated with undesirable plant products (such as plant dust) through careless distillation procedure, or contains colour or aroma molecules undesirable for the perfumer. The end product is not necessarily an improvement in quality8c but is what the perfumer wants.
Synthetic Oils
Apart from adding synthetic components to an essential oil, a chemist can put together only synthetic molecules, to simulate the aroma of an essential oil, and, whatever plant name may be bestowed upon them, many cheap perfumes (and ‘aromatherapy’ toiletries) are totally synthetic (as indeed are many flavourings). It would be wrong of me to say that these have no effect whatsoever, as any smell, from whatever source, has an effect on the mind – even a bad smell – and can make one feel relaxed, awake, hungry or nauseous (for example, new-mown grass, frying bacon, nail polish remover, etc.)
However, a synthetic smell cannot, in my opinion, help a health problem without leading to side effects, as is often the case with synthetic drugs. There are scientists today who would argue with this and I believe such people are forgetting certain principles.
When science removes the therapeutic molecules or components from plants or essential oils, the administered result seems to give side effects. It is now appreciated that in the whole plant, or whole essential oil, there are many apparently useless components, including several that we cannot identify. These are believed to be ‘quenchers’ of the side effects which therapeutic agents in isolation could, and indeed do, cause. A good example of this is cinnamon bark oil. Cinnamic aldehyde, a major constituent of this oil, was found to be a severe irritant and the oil was therefore branded as an irritant. However, the complete oil, when tested, was found to be an irritant only on certain people – and to a much lesser degree.9 The other components or constituents of the whole oil were quenching the irritant quality of the aldehyde, no-one knowing exactly which ones or how. (The whole oil may, however, be a sensitizer for some people – see chapters 3 and 6.)
If an essential oil can be made using synthetic versions of the chemicals that are known to occur naturally in the plant, the unidentifiable ones will be absent, therefore the result will not be a complete and whole essential oil. Thus it will most likely produce side-effects, as do other unnatural drugs. Nature always knows best!
There are scientists who believe that essential oils made in the laboratory will have exactly the same therapeutic effect as those made by Mother Nature; it is true that tea tree, the simplest essential oil, can be made in a laboratory and may help a health problem (though perhaps producing side effects with prolonged use). If asked whether there is any difference between synthetic and distilled tea tree, the scientist is bound to admit that there is a slight measurable difference in the carbon atoms, therefore giving a clue as to whether the oil is synthetic or not. He will also tell us that despite this, the properties are exactly the same! With more complicated oils, there are many unidentified components present in very small quantities, which cannot be imitated; hence such an oil would not be ‘whole’ as we know the meaning of the word.
This brings us to the question of vital force in essential oils. Almost every aromatherapist believes in this subtle, invisible, intangible quality that is not susceptible to any scientific proof. ‘Life force’ is thought to be due to some indefinable process (perhaps comparable to photosynthesis) whereby some part of the electro-magnetic energy of the sun’s rays is converted into an energy which is stored in the essential oil cells in the plant.
The scientific community will quote the dictionary definition of vital force; ‘the force on which the phenomena of life in animals and plants depend – distinct from chemical and mechanical forces operating in them’. In other words, once a plant is harvested it is dead.
The only difference between a living human being and a body in the immediate moment of death is this ‘vital’ or ‘life’ force. At that particular moment, nothing else has changed. The spirit or soul is a different matter for consideration; many religions, including Christianity, believe this lives on. In my opinion, the spirit of a plant (its energy) ‘lives on’ in its synergy (it is no longer living) and it is this special and unique mix of natural chemicals – which no human has been able to put together – which gives an essential oil its subtle, invisible, intangible, vibrant quality.
Quality
I have to be honest and admit that synthetic and adulterated oils will ‘work’ to a certain extent (in the latter there could be a high percentage of the natural oil present). It is the quality which is different. Optimum quality is paramount not only in order to get the best results, but also to avoid the risk of possible harmful side effects. A bonus is that less essential oil is then needed in order to be effective, a fact often forgotten by people who buy oils on the false economy of price. Organic oils are best of all (see below).
Despite the fact that we obtain most oils direct from the farming community, tests are carried out to determine the levels of the constituent components,
