Practical Aromatherapy - Learning About Using Essential Oil Chemistry.
Chemistry. Already
getting nervous? The chemistry chapters of essential oil texts are the
most frequently skipped, even by natural health professionals. But it
can be fun and useful...really! Knowing what essential oils are made
of, and how this affects their aroma and therapeutic value can have a
big impact on the efficacy of your aromatherapy practice. Understanding
the basics can help you
make better choices in
essential oils, and better choices in their application. Plus, this can
give you the foundation for further understanding of true 'medical
aromatherapy', as practiced in much of the rest of the world. So here's
a primer on the chemistry of essential oils, with some common examples
and important tips to help you grow as a holistic medicine practitioner.
So what is it that makes an essential oil different than every other
oil we're familiar with? They don't feel the same, they don't act the
same, and they certainly don't smell the same. Essential oils and the
so-called 'fixed' oils (you may also know them as carrier or base oils
- like Sweet Almond, Apricot Kernel, Evening Primrose, etc) are
distinctly different in their molecular structure. While both essential
and fixed oils share common basic atomic elements of Carbon and
Hydrogen, that's really where the similarity ends. Fixed oils are made
of triglyceride structures - three long chains of carbon atoms, with
hydrogens bonded at various places. The length of the chains and the
position and number of hydrogens define the nature of the oil; if
hydrogens are bonded to every available location, the oil is
'saturated', for example. One missing hydrogen is 'mono-unsaturated',
more than one is 'poly-unsaturated'. The long chains and relative
consistency of the molecular structures makes fixed oils 'oily', and
does not allow them to evaporate quickly.
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.
The therapeutic action of an essential oil is primarily determined by
the functional groups found in the molecules that make up that oil
(here, many folks might be responding with "Say what?!?"). An essential
oil is actually made up of many liquid chemicals; sometimes more than
one hundred distinct chemicals are found in one pure essential oil.
Each of these chemicals is formed of a carbon-hydrogen structure with a
functional group attached - it is the combination of the base structure
AND the attached functional group that makes a single, unique molecule.
And MANY of these unique molecules combine to form ONE essential oil.
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.
What does this mean to the lay-practitioner? That it's important to
find a nice smelling lavender oil! Each of the individual chemicals has
a distinct smell, talked about in terms of 'notes' within the overall
lavender aroma. Some of these are sweet, some citrusy, some are
herbaceous, and some can be camphorous. A precise amount of each will
create a certain lavender aroma. Some lavenders are more sweet (and
therefore more relaxing), others are more herbaceous (and more
anti-microbial). Three important points should be noted regarding
selecting by aroma: First, there can be significantly different aromas
from the same species of plant, even when the essential oils are of the
highest quality. You can often use your intuition to select the best
variety for your needs (as between the sweeter more relaxing, or the
herbaceous more 'medicinal' lavenders). Sedond, some plants (e.g.
Rosemary and Thyme) have chemotypes - this specifies a predominant
chemical in the essential oil - each being used for a certain
therapeutic application. Know which chemotype is best suited to your
needs before making a selection. Finally, it is most often the
essential oil that smells the most 'true' to you that will be the most
beneficial. Your senses can naturally detect what is good for you and
what is not, if you're willing to listen to them impartially.
All essential oils are subject to similar variations in production
methods or the manipulation of their molecular make-ups through the
addition of synthetic chemicals. For the most therapeutic benefit, it
is always best to use true, carefully-made essential oils. To do this,
find a source that is dedicated to supplying only the highest grades of
oils. Examine their product's aromatic quality and business practices
and so that you are comfortable with their dedication to your health,
not just their bottom line. Listen to your intuition and your own nose;
they won't lie to you! With experience, your ability to discern between
subtly different grades of oils will become more astute. With even more
education and skill, you'll start to recognize individual chemicals
within an oils aroma, and make the best decisions as to which oils will
have the most profound therapeutic affects for you, your family, or in
your professional practice.
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