Essential Oil Chemistry: Why Aroma Matters

Uh oh. Chemistry - the word itself can make one's eyes glaze over. But wait, this is 'essential oil chemistry'. MUCH more fun! While even beginning aromatherapy students are put off by the mere mention of the subject, they eventually realize the importance of understanding at least the fundamentals. The basics of essential oil chemistry will help you appreciate what gives a fine oil its unique aroma, help you more carefully discern a good oil from a second-rate one, and can improve your practice of using essential oils therapeutically. The greatest benefits of essential oils lies in their potential for true medicinal applications, where their antiviral, antimicrobial and anti-inflammatory properties are effectively utilized. And it is the understanding of their chemistry that enables the practitioner to select the right oils and use them most appropriately. Convinced? Well here's a primer to get you started...

So, why are essential oils called 'oils' anyway? They don't feel greasy, and they tend to evaporate completely, unlike common 'fixed' oils (such as olive, grapeseed, hazelnut and the like). Essential oils and fixed oils share a similar chemical foundation: their structures are based on the linking of carbon and hydrogen atoms in various configurations. But this is really where the similarity ends. Fixed oils are made up of molecules comprised of three long chains of carbon atoms bound together at one end, called a triglyceride. Every fixed oil is made up of just a few different triglyceride arrangements - olive oil, for example, is primarily made up of oleic, linoleic and linolenic acids (the names of particular carbon-hydrogen chains forming the triglycerides). Their long-chain shape holds them in a liquid state which does not easily evaporate.

Essential oils are 'volatile' oils - oils that DO easily evaporate. Their chains of carbon atoms to which the hydrogens attach are not as long or heavy, and are much more complex. Many essential oil structures are not really chains, but ring, or multi-ringed shapes with diverse sub-units - called 'functional groups' - sticking out in various directions. Like their fixed oil counterparts, essential oils are lipophillic - meaning 'fat liking'. The fat-liking nature of both fixed and essential oils makes them easily absorbed by our bodies. Because of their typically smaller structures however, essential oils are absorbed more rapidly than fixed oils, and can easily penetrate deep into the body. Despite their plant origins, this lipophillic nature of essential oils makes their profound healing action on the human body possible.

Most of the therapeutic activity of an essential oil can be attributed to the functional groups of the individual chemicals that make up the oil. There can be over a hundred identifiable molecules in one essential oil. Each of these molecules, as mentioned earlier, is a chain or ring (or multiple-ring) structure of carbon atoms linked together with hydrogen atoms bonded to them in various configurations. Every chain or ring has a functional group attached - a functional group is defined by Salvatore Battaglia in 'The Complete Guide to Aromatherapy' as: "a single atom or group of atoms that...has a profound influence upon the properties of the molecule as a whole. It is often referred to as the chemically active center of the molecule".

The extremely complex nature of essential oils becomes apparent from this description. There are an almost infinite number of molecular combinations that can be formed from the building blocks of chains, rings and functional groups. And any SINGLE essential oil is made of many, sometimes even hundreds of these molecular combinations. Yet while this may sound complex, you needn't know ALL the chemical details to use oils therapeutically. It IS helpful to know that each oil is made of many molecular forms, that all the molecules within each oil exert some biologic effect, and that it is the SYNERGY of ALL these molecules together that create the sum total of an oil's therapeutic action AND its aroma. Nearly every laboratory study comparing complete, pure essential oils to one singled-out molecule that was thought the 'active ingredient' shows the essential oil to be more active.

Many factors in an essential oil's production affect the total number and relative amounts of individual chemicals found in the final product. These include where the plant was grown, soil and climate conditions, time of harvest, distillation equipment, plus the time, temperature and pressure of distillation. This can give you an idea as to why two varieties of the same oil can smell so different: The full, beautiful bouquet of a fine essential oil will contain a myriad of notes, telling you that all natural components are present and in balanced amounts. Poorly distilled oils may lose some of the secondary constituents during production, and adulterated or synthetic oils may not have some of the trace components at all, detectable by your nose as a flat or uninteresting aroma.

As an example, let's look at Lavender, the most commonly used of all essential oils. More than 50 individual molecules are present in a high-quality Lavender. As noted earlier, all of these chemicals work together to produce a therapeutic effect. For example, 'linalool' is antiviral and antibacterial; 'linalyl acetate' is also emotionally calming; other constituents including cineol, limonene, alpha-pinene and others are all noted for specific biologic and aromatic activity. It is the combined, balanced action of these chemicals that make lavender such a useful healing agent - no one chemical can be singled out and used to give the same profound results.

So how is this synergy reflected in Lavender's aroma? Each of these chemicals has a unique smell; some are sweet, some are camphorous, some citrusy and some herbaceous. It is all these chemicals together, a precise amount of each, that gives each lavender variety its distinct aroma. And your nose knows this! One can tell the difference between a well-made, complex lavender oil with many notes within the aroma, and one that is flat or plain, which may be chemically imbalanced or missing some trace constituents. One can easily tell the difference, for example, between common Lavendula officinalis, and the finer Lavendula angustifolia, which contains a higher proportion of sweet-smelling linalyl acetate and less sharp-smelling camphor. Further, lower quality lavender plants may occasionally be sprayed with linalool before harvest to enhance the production of linalyl acetate by the flowers. While the end-product may smell sweeter, the process actually creates an imbalance in the overall healing synergy of the primary and trace molecules. All these oils will be labeled 'Lavender' on the store shelf, yet the finer, natural lavender will have a more beautiful, balanced aromatic bouquet, and is considered the most holistically healing variety by the world's leading aromatherapy practitioners.

A balanced approach in aromatherapy, as in all of natural medicine, is best. The most effective practitioner will have a well-developed 'internal pendulum' combined with a solid education. Significant variations exist in the quality of essential oils; it is really cost effective to buy the higher grades of oil, as their synergy of expertly distilled chemicals will have the greater therapeutic action. Use your nose, knowledge and intuition to find a source you trust, that delivers consistently high-grade oils for a reasonable cost. Use these same faculties to skillfully select and apply the appropriate oil for each circumstance. Essential oils are complex by nature; at the same time, they have an exceptionally broad scope of therapeutic applications. Hopefully, this little bit of aromatherapy chemistry will enrich your ability to support your own health, and the health of those around you.

The author is a natural health professional utilizing vibrational medicine in his personal and professional practice. He is the co-owner of the Ananda Apothecary, specializing in wildcrafted and organic essential oils and essential oil blends.

Article Source: http://www.wellnessarticlelibrary.com

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