DESARROLLO DE LA VISITA

In a nice environment, people feel better. This is hardly a discovery, but some ex- perts have actually proved this connection using scientific methods. Even the symp- toms of sick people feel less severe if the surroundings are pleasant, and the scents

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of essential oils can contribute to this. Aromatherapy certainly improves the emo- tional states of people, but does it actually heal?

Aromatherapy is medical treatment with essential oils. Essential oils are volatile liquids obtained mostly by distillation (occasionally by pressing, extraction with a solvent or supercritical extraction) from plants. Some families of plants have a high content of essential oils and have a scent similar to that of the plant.

Although the name essential oil and its variation ‘ethereal oil’ both refer to the volatility of these compounds, this is not always accurate since the strong scent is in fact caused by evaporating molecules even if they are less volatile than e.g. wa- ter. Most components in essential oils are hydrocarbons with 10–15 carbon atoms. Their composition is very different from those of fixed (or fatty) oils (sunflower oil, olive oil), which are glycerol esters of fatty acids. These fatty oils are not volatile and they do not have pleasant (or other) scents, either.

A number of ancient cultures used essential oils or the plants containing them. The first distillation of suitable oils was found in today’s Pakistan and is estimated to be about 7000 years old. China and Egypt have had a written history of essential oil use for several thousand years. Aromatic plants and their oils or extracts played an important role in both medicine and religious ceremonies. The first cosmetics were mixtures of essential oils, which is true even today, although some compo- nents are produced synthetically. Scented incense was also commonly used. This is the origin of the word ‘perfume’ as the Latin preposition per means ‘through or along’, and fumo means ‘to smoke’.

Plants producing essential oils were used in medicine, both externally and orally. Ancient Greek physician Hippocrates of Kos (c. 460 BC—c. 370 BC) recorded that scented plants were burned during a plague in Athens. Today, it is clear that several essential oils are active against bacteria, but the plague was not stamped out because

Fig. 3.14  High Pressure Liquid Chromatograms of an allopathic ( upper blue trace) and a homeo-

pathic ( lower black trace) medicine. The peaks labeled with A correspond to agnuside, C to casti- cin, respectively. (Authors’ own work)

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of this effect. It is more likely that the strong scent was too much for rats, which are the hosts of the fleas spreading the plague pathogen.

Essential oils are evaporated today for medicinal purposes in the same manner as in ancient and medieval times. Yet aromatherapy does not truly have such long traditions. Today’s method was invented less than 100 years ago. The creator was French chemist René-Maurice Gattefossé (1881–1950), who burned his hand very badly in a 1910 laboratory accident and later claimed he treated it effectively with lavender oil. His pain was promptly relieved and the burn healed much faster than expected and without notable scarring. After this “miraculous recovery”, Gattefossé devoted his life to studying essential oils. In 1937, he published his findings in a French book titled Aromathérapie: Les Huiles Essentielles, Hormones Végétales. This was also the first time the word aromatherapy appeared in print. The book is still considered the Bible of the method, which became very popular, especially in the French-speaking world. An English translation was only recently published in 1993.

Due to a kind of Renaissance in alternative medicine today, aromatherapy is ex- periencing a golden age. Numerous books and innumerable (often self-proclaimed) traditional healing experts recommend aromatherapy, but as is often the case, the real value and limitations of aromatherapy remain unknown to patient and healing expert alike.

Aromatherapy relies on interviewing the patient in order to select the suitable essential oil. The application of the oil follows, and this can be done by evaporation and inhalation, but more often it means skin massage. For massage, the essential oil is always diluted with a neutral fatty oil such avocado, olive, or peanut oil, because the essential oil alone often has an irritating effect on the skin. The massage takes one or two hours. The personalized treatment and the interview usually build up trust between patient and therapist, which has psychological advantages. The es- sential oil massage provides a nice, calming effect on most people, so it is hardly surprising that most patients report feeling better and relief of some symptoms.

Books do not only recommend aromatherapy to simply relax people, they claim real physiological effects as well against acute (ear ache, bronchitis, migraine) and chronic symptoms (hypertension, eczema). An examination of the clinical trials re- veals that very few of the claimed effects were scientifically tested. The Cochrane Library database contains 121 studies related to aromatherapy. Most of these fo- cused only upon distress and depression, and the selection of essential oils studied was also quite narrow: lavender oil seems to be immensely popular among scien- tists.

From these scarce data, it is clear the most practices in aromatherapy are not based on science, and to make a clear distinction, several experts have proposed that experimentally proven methods should be called aromachology.

Lavender, as the flagship of aromatherapy, deserves more explanation. The relax- ing effect of this essential oil has been studied and confirmed by a number of animal tests and in vitro (outside living organism) experiments. The physiological effect resembles that of some known medicines, and one possible mechanism relies upon inhibiting the binding of glutamic acid to a receptor. Glutamic acid is an essential

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amino acid and is known to cause stimulation of the nerve cell. Another contribut- ing aspect might be the enhanced receptor binding of sedative gamma-aminobutyric acid. The active ingredients of lavender oil are lipophylic, which means they can ex- ert their effect directly upon the brain after uptake through the mucous membrane of the nose (inhalation) or by skin absorption (massage). A particularly valuable study monitored the blood levels of lavender components. The two most significant in- gredients, linalool (Fig. 3.15) and linalyl acetate, were detectable both in blood and brain tissue 15 min after inhalation. Similar results were obtained when lavender oil was absorbed through the skin in a massage. Although the connection between blood concentrations and clinical effects was not studied, these data alone show that the effect of lavender must be more than just a placebo with a pleasant scent.

The relaxing and sedating effects of orally taken or inhaled lavender oil have been proved in a number of animal tests showing lengthened sleep times or de- creased movement intensity. Pure linalool or linalyl acetate had effects similar to those of the oil. Linalool was even studied in human tests. Only ( R)-(–)-linalool was active and this represents more than 90 % of the linalool in lavender. The other enantiomer, ( S)-( + )-linalool did not have a similar effect. This is also evidence of some tangible therapeutic effect as receptors are expected to bind the two enantio- mers (which do not have the same scent either) in different ways.

Paradoxically, the pleasant aroma of lavender makes the scientific study of its effects quite difficult. It is next to impossible to carry out a placebo-controlled test, as the characteristic scent makes the presence of the active ingredient obvious. The effect of lavender oil in bath water or massage oil was also investigated in a handful of studies, and these also turned out to be positive. In addition, EEG tests have also proved the oil’s effects on the central nervous system.

In contrast to lavender oil, scientific data are very rare for other essential oils used in aromatherapy. Some of them seem to have real pharmacological effects on the central nervous system, but the evidence is not as strong as in the case of laven- der oil. Joint and muscle pains can be relieved by massage-aromatherapy, but avail- able evidence does not demonstrate anything more than just the result of improved blood circulation. As scientific studies are seldom carried out on other essential oils, their application has no confirmed role in modern medicine. As this is a case of absence of evidence, and not evidence of the absence of effect, further and more detailed studies may change the current professional zeitgeist.

Fig. 3.15  Enantiomers (mir-

ror image molecule pairs) of linalool, a major ingredient of lavender oil: ( S)-( + )-linalool and ( R)-(–)-linalool. The former has a sweet smell, the latter is characteristic of lav- ender. (Authors’ own work)

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