About Essential Oils
God of his infinite goodness and bounty hath by the medium of Plants, bestowed almost all food, clothing and medicine upon man.' Gerarde's Herbal (1636)
Aromatic oils are used in three Classes of consumer good: foods, toiletries, and medicines. In Foods they are used as natural flavorings, such as oils of lemon, orange, and lime in marmalades. In cosmetics they are incorporated both in perfumes and, less often, as natural active ingredients; they are also widely used in toothpaste flavorings. In medicine they are used not only as flavorings agents but as therapeutic ingredients in their own right. The use of clove oil for toothache, peppermint oil for indigestion, and eucalyptus for inhalations is well known. Essences are also used in a number of patented medicinal products, including antiseptic creams and ointments, inhalations (such as friar's balsam, hair tonics (bay rum) ointments for skin diseases, rubefacient liniment for rheumatic pain, and so on.
Primarily they are included in preparations for external application, although recently a UK patent was taken out for a gallstone-dissolving product which contains a number of essences. Essential oils are odorous and highly volatile (they readily evaporate in the open air). They are quite different from fatty oils, and have a consistency more like water than oil. Their chemistry is complex, but they generally contain alcohols, esters, keytones, aldehydes, and terpenes. The odoriferous materials are formed in the chloroplasts of the leaf. Here they combine with glucose to form glucosides, which are transported around the plant structures.Most essences are clear, although a few (especially) the absolutes ) are colored, some red (benzoin), others green (bergamot) yellow (lemon), or blue (chamomile). They are soluble in alcohol, ether, and fixed oils, but insoluble in water.
The oils are present in tiny droplets in a large number of plants, especially those most commonly used for their culinary and medicinal properties. They occur in roots (calamus), leaves (rosemary), flowers (lavender), barks (cinnamon), resins (myrrh) and the rind of fruits. The presence of essential oil in oranges can be demonstrated by squeezing a section of the peel next to a lighted match: the oil droplets will spray out and briefly ignite as they pass through the flame. The scent of flowers and herbs is due to their essential oil content, as in the spiciness of spices. Essences are usually extracted by distillation. This involves placing the plant material in a vat and passing steam through it. The essences evaporate along with water and other substances. The distillate is then cooled, and the essences (which are not water -soluble) are easily separated from the water.
Sometimes other methods are favored , the most common alternative being extraction by volatile solvents, The plant material (usually flowers) is washed in a suitable solvent, such as alcohol, until the essence is dissolved in the solvent. It is then separated by being distilled at a precise temperature which condenses the oil but not the solvent: the oils thus obtained is known as an 'absolute'. Yet another method, which is usually employed for citrus fruits, is carried out completely by hand. The peel is cut off from the pulp, and then squeezed over a bucket, which collects the oil along with the juice. This has now been largely superceded by mechanized pressing, and distillation is also sometimes used.
While they bare in the plant the essences are constantly changing their chemical composition, and move from one part of the plant to another according to the time of day and the seasons. this is why plants destined for oil extraction must be picked at a certain time of year, in certain weather conditions, and usually at a certain time of day. The odor and chemical constituents of essences change with different soil conditions, variations in climate, and methods of cultivation. This is why oils from certain countries like Bulgarian Rose and Ceylonese cinnamon, are considered to be of a higher quality than those from other countries.The amount of essence present in the plant varies from about 0.01% up to 10% or even more. Rose petals, for instance, contain very little essence, and up to 2'000 kg petals may be needed to produce 1kg of oil. Some oils, like those from rose, jasmine, carnation and tuberose, are particularly heavy and concentrated (and so expensive) very little is needed. Some essences, such as Bulgarian rose Otto, are solid at room temperature and need to be warmed before they assume the usual fluidity of essences.
The effects of heat, light, air, and moisture generally have a damaging effect on essential oils. They should therefore always be kept in the dark, airtight bottles and in cool, dry conditions. There are hundreds of aromatic plants only some of which are used to produce essences commercially. About a third of the plants traditionally used in herbal medicine are aromatic. No two of them are exactly alike, and the properties of each are unique. The essence of a plant is like it's personality. All animals, including humans, have their own characteristic smell, quite apart from what we call body odor. We are not commonly aware of our own scent, nor usually of other people's. We may, however, perceive it on a subconscious level, and it may influence our feelings towards each other more than we realize.
There is little doubt that scent has some practical use in the plant kingdom. Animals (and probably humans) are sexually attracted by aromatic substances called pheromones. It is suggested by Peter Tomkins and Christopher Bird in their Book The Secrets Life Of plants that essences have a similar role:
'Flowers that remain unfertilized emit a strong fragrance for as many as eight days or until the flower withers and falls; yet once impregnated the flower ceases to exude its fragrance, usually in less than half an hour.'
This idea places plants is more sexual or animal light than has so far been generally accepted. Nevertheless, there are plants which exhibit other animal traits, such as carnivorous plants, which eat insects. A more commonly accepted idea is that the scent of a plant attracts certain insects which, by moving from plant to plant, cause fertilisation to take place. Essential oils are in fact used commercially to attract or repel certain insects. The essences of many plants are a natural defence mechanism, repelling insects which would otherwise harm the plant.
It has also been said of essences that they are mere waste product of plant metabolism. Surely if its use becomes known it ceases to be a mere waste product? I find it hard to believe that essences, which are in general highly complex and pleasant substances are merely waste products. I prefer to believe that aromatic plants were created for man to use and enjoy, as perfumes and as medicines, and that the aromatic principle also serves as aid to plant fertilisation. After all, it is merely coincidence that we find flowers pleasing to look at and to smell?
'From inside comes the voice and from inside comes the scent. Just as one can tell human beings in the dark from the tone of voices, so in the dark, every flower can be recognized by its scent. Each carries the soul of its progenitor.'
The above lines were written by a nineteenth-century German doctor, Gustav Fechner. he was a man of great spiritual insight, and could see the aura of plants. It seemed to him that 'plant people', calmly living their lives in one spot, might well wonder why we humans were so keen on rushing about. He wrote:
'in addition to souls which run and shriek and devour, might there not be souls which bloom in stillness, exhale fragrance and satisfy their thirst with dew and their impulses by their burgeoning?'
Could not flowers, Fechner asked, communicate with each other by the very perfumes they excude, becoming aware of each other's presence in a way more delightful than by means of the verbiage of humans which is seldom delicate or fragrant except, by coincidence, in lovers?.
Reference: The Art of Aromatherapy: Robert Tisserand 1979-1987
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