Chapter 1: An Introduction to Essential Oils
physical and chemical properties of volatile aromatic compounds
allow them to quickly enter the gas state, move through the air, and
directly interact with olfactory sensors in the nose.
Essential oils can be made up of anywhere between 1 and
1000 different compounds with different chemical identities.
For example, Birch oil is almost
entirely composed of one
compound: methyl salicylate.
Spikenard, on the other hand,
contains hundreds of compounds.
Most oils fall somewhere in
between these two extremes. For
instance, Frankincense essential
oil contains over 65 distinct
chemical compounds in various
quantities.
The different compounds in an
essential oil are known as constituents. Each constituent has its own
distinct structure, meaning that the shape, size, and arrangement of
chemical bonds in that molecule is unique. The different constituents
in an essential oil determine both the oil’s aroma and the benefits it
offers.
The exact composition of an essential oil varies between plant
species. When speaking of essential oils, the word “composition”
refers to the oil’s constituent makeup or, in other words, what chemical
constituents it contains and how much of those constituents are
present. For instance, Bergamot essential contains over 35 different
compounds, but it has especially high levels of two constituents
called limonene and linalyl acetate. Blue Tansy essential oil, on
the other hand, contains over 50 compounds, with the two most
abundant constituents being chamazulene and sabinene.
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