The principles of aromatherapy Aromatherapy techniques
  • The principles of aromatherapy
  • Aromatherapy techniques

The principles of aromatherapy

The term aromatherapy indicates the use of essential oils derived from the botanical kingdom (in some cases also from the animal kingdom) for medical use for the purpose of prevention and treatment.

Archeology has shown that since the most remote antiquity, particularly in the Mesopotamian and Chinese civilizations and, later, during the Egyptian and Greco-Roman era, the art of distilling and preparing essential oils for use was practiced therapeutic, for well-being, for personal and environmental hygiene, for massage therapy and, above all, cosmetic purposes.

The discovery of the optimal distillation technique is traced back to the Arab doctor Avicenna (Abu Ali Ibn Sina, 980-1037). Throughout the Middle Ages and until the eighteenth century the various schools of medicine recommended the use of aromatic essences to restore the "corruption of air and body" for preventive or curative purposes, especially in times of pestilence.

The fundamental treatise on the subject, the Book of true art of distillation (Das nüve distilier buoch der recten kunst, 1531) was written by the German physician Hieronymus Brunschwig.

In modern times, at the turn of the 19th and 20th centuries, the studies of the experimental doctors M. Chamberland, B. Cadéac, A. Meunier and E. Cavel, who directed their research especially in the field of antiseptic aromatherapy, should be remembered, identifying dozens of plant essences with antimicrobial activity; in fact, these pioneers anticipated the current flourishing of scientific studies on the subject by decades.

The term aromatherapy was introduced only later, in the book Aromathérapie: les huiles essentiales, hormones végétales (1937), by the French chemist René Maurice Gattefosse; this researcher hoped to deepen the studies on the pharmacological aspects of essential oils and their therapeutic application in modern medicine.

The next step was taken by Dr. Jean Valnet, who deepened the science of aromatherapy and described it in the fundamental book Aromatherapy. Traitement des maladies par les essences de plantes (1964). In 1971 Valnet founded the first company for studies and research in aromatherapy and phytotherapy and in 1981 established the French College of Phyto and Aromatherapy.

The use of essential oils with antimicrobial activities in the therapy of infectious states has been meticulously exposed by Dr. Paul Belaiche in the Traité de phytothérapie et d'aromathérapie (1979); in L'aromathéraphie exactement (1990) Pierre Franchomme and Daniel Pénoël, on the other hand, developed further aspects of medical aromatherapy.

The scientific bibliography is rich in works in the field of aromatherapy, and in every part of the world many scientific studies are underway concerning the properties, especially antimicrobial and antiseptic, of natural essences.

The function that essential oils play in the life of plants is manifold and important. They are produced for various reasons, which include the defense against insects and pests or harmful microorganisms and fungi, the "recall" of insects useful for the transport of their reproductive principles, environmental communication with other plants, survival in areas of strong botanical competition, the protection from dehydration phenomena in very dry areas or in adverse climates. These substances are concentrated in different parts of the plant: flowers, leaves, roots, fruits (both inside and in the outer skin), wood, bark, resin.

Laboratory analyzes have identified a series of active ingredients making up essential oils, including terpenes, esters, aldehydes, ketones, alcohols, phenols and oxides. The mechanism of action of essential oils is investigated through pharmacological studies conducted on the individual isolated components since, given the chemical complexity of whole oils, it is practically impossible to determine the exact and complete pharmacognosy on them. It should be noted that each essential oil is characterized by a complex composition, in which the various ingredients act according to particular synergies, which entails additional levels of difficulty in the exact evaluation of the clinical effects produced.

In ancient times, the extraction process from plants involved immersing branches or leaves in water in containers covered with wool or cotton fibers; heating produced the evaporation of the volatile parts of the oils, which impregnated the fabric; the fibers were then squeezed, by hand or press. Both the ancient Chinese, and the Mesopotamian and Egyptian civilizations then developed distillation techniques which, albeit with subsequent progress and improvements, remained substantially unchanged for centuries.

Modern technology employs the extractive methods listed below.

Steam distillation Takes back and updates the ancient system and is performed using multiple containers. It starts by boiling the water in an alembic, in which the shredded plants are immersed. The steam dissolves the aromatic parts, which are then conveyed into a cooled coil. The distillate, lighter than water, floats, but in certain circumstances settles on the bottom; in any case, it is separated and collected. The process is perfected by successive distillations and purifications, which involve different degrees of quality and concentration of the essential oil thus obtained.

Hydrodiffusion and percolation This is a technique that involves the diffusion of steam from above inside the container where the parts of the plant are placed. The product is collected at the bottom, through a coil immersed in a cooling water bath, and then separated.

Extraction with chemical solvents Generally the solvents used are hexane, petroleum ether, methane tetrachloride and benzene. The substance produced with this technique, called concrete, is subsequently subjected to alcohol treatment processes that enhance its aromatic properties: this residue is said to be absolute and for therapeutic use it should not be marketed in concentrations higher than 5 ppm (parts per million) . The extraction with chemical solvents is mainly used by the cosmetic industry, for obvious reasons related to saving time and money, but it has unpleasant disadvantages, due to the residues of the solvents themselves and of other non-volatile substances, and it is certainly not appreciated by the " purists ”of aromatherapy; it can also produce skin irritating or allergenic oils, and lends itself to adulterations.

Resin extraction Toluene or alcohol is used as a solvent, so as to separate the heavy and odorless part from the essence. Unfortunately, the solvent is only partially recovered.

Extraction according to the method of enfleurage It is a method of ancient tradition, perfected today and nevertheless used exceptionally as it is very expensive. It has the advantage of obtaining excellent and precious quality oils and is mainly used to prepare delicate essences, that is, those of flowers. The plants, as was done in the past, are immersed in oil or pork fat in order to separate their essential oils. The flowers need to be renewed approximately every two days and the process takes weeks. At the end of the following steps the essential oil is extracted with alcohol.

Extraction by cold pressure It is obtained by a mechanical press, which acts on the peels of the chopped citrus fruits, and in the presence of scarce water. The mixture produced is then separated in a centrifuge.

Carbon dioxide extraction Method recently introduced, it consists in the use of carbon dioxide or butane under pressure, which liquefy by separating the essential oils from the plants.

A delicate aspect concerns the authenticity of essential oils. The quality of the products on the market is often rather poor and, alongside very high-cost pure preparations, there are many batches of counterfeit or diluted oils, "cut" with artificial essences, of variable and uncontrollable efficacy and toxicity. The essential oils used for therapeutic use must be of origin and of impeccable quality, and for this reason the exact definition of the chemotype, the natural origin, the distillation method and purity are of fundamental importance.

The term chemotype defines the diversity between botanical individuals of the same species. Even if the external appearance and the chemical composition could suggest that the plants are all the same, and therefore indistinguishable in terms of the therapeutic effects produced, on careful examination they are instead quite different, as each originates from adaptation processes to various soil, climate and environmental conditions. Therefore, the same species, for example lavender or thyme, shows particular chemotypes suitable for survival in the specific habitat in which the single plant grows, and this entails a different synthesis, but also different qualities and concentrations of essential oils and active substances., to be studied carefully in relation to possible therapeutic applications.

The field of application of essential oils is vast. First of all, we must remember the antimicrobial properties used in the treatment of infections of the nasopharyngeal, bronchial and pulmonary pathways, but also those used in the dermatological, gastroenterological and urological fields. Further proven effects concern analgesia, anti-inflammatory, antifungal, mucolytic, expectorant, spasmolytic, cicatricial, diuretic, toning activity (a certain hormonal and immune modulating action also seems to be ascertained). To these indications, aimed at both organic and functional pathologies, must be added anticonvulsant neurological therapeutic effects: since the thirties of the twentieth century, in fact, many scientific studies have examined the use, in the context of psychotherapy, of essential oils, of which they are influences on mood, tiredness, anxiety, depression have been investigated; they also affect dreamlike aspects and the appearance of suggestive or hallucinatory emotional states.

In the common imagination, the sense of smell is somehow the most mysterious of the five senses. The nose represents only the external and peripheral part of that sophisticated system which presides over the collection of odorous sensations, as its mucous membranes and its vibrating hairs put the environment in direct contact with the central nervous system.

Each breath involves the registration of the infinite molecules dispersed in the air and the immediate translation into electrical impulses, conveyed to specialized areas of the brain. These signals are not mediated by the cerebral cortex, but immediately reach the brain, the deepest and oldest part of our brain. This system, called limbic, reacts to electrical stimuli related to odor, producing neurochemical stimulating or relaxing, sexual, immunomodulating and pain-relieving substances: these are instincts that belong to the animal nature and show our sympathy or sensory aversion towards other people, environment, food.

The scents and smells induce complex moods and strong reactions. The olfactory memory remains imprinted in the memory and is linked to the specific sensations that involved it. The scents indissolubly fix memories and are able to recall them directly, indelibly over time, without rational intermediation: this property allows memories to emerge and awaken from the deep, combined with the original sensations experienced at the time of the olfactory and emotional experiences lived . These are subtle perceptions connected with the aerial nature of the soul. Heraclitus, in a fragment of his, writes: "In Hades souls perceive by sniffing".

If it is true that the nose is in charge of deep knowledge of things, it is necessary to consider its ability to grasp the "ethereal" spirit of what it is recording, the value of the intimate memories that move within us. The sense of smell is responsible for bringing truth to our conscience in a varied palette of sensations ranging from disgust to ecstasy; for example, it can evoke disturbing perceptions of unease, manifest something non-verbal that belongs to refusal, to intolerance.

The scents stimulate deep influences in man: in the form of pleasant or unpleasant olfactory sensations, they determine sympathy and aversion, thus inducing many sexual behaviors and choices. The unconscious is impressed by the various essential oils that come to modify its mood and mood, relaxation or emotional tension. In addition, perfumes warn about any dangers hidden in food or the environment.

Their ability to stimulate creativity is well known: not a few artists have used specific aromas to enhance their skills of concentration and inspiration. Finally, perfumes manage to influence automatic body functions, such as breathing, digestion, heart rate and hormone production.

Essential oils have peculiar characteristics that are connected with their action and determine their correct use. They have the prerogative of being easily absorbed by the skin and conveyed from there through the circulatory stream.

Aromatherapy, of all natural medicines, is perhaps the least "sweet", as it uses very concentrated and active substances, some even potentially toxic if poorly managed or administered in excessive doses: in cases of allergic patients, children, pregnant women (some oils cross the placenta) or breastfeeding, therefore extreme attention must be paid to their use.

Certain substances contained in essential oils, for example ketones, are able to overcome the blood brain barrier and cause neurotoxicity phenomena; others, such as phenols, can create liver or kidney damage, and still others, including aldehydes, present oncogenic risks.

The oral and cutaneous routes of administration are particularly delicate to manage and should be practiced only under the strict supervision of an expert doctor.

Essential oils are very sensitive to physical factors, and therefore should be kept away from sources of heat and light, protected in dark glass bottles.

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