Understanding Essential Oils

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What Are Essential Oils?

essential oil photo
Essential oils are highly concentrated plant produced compounds that are effective in protecting plants and promoting the reproduction of plants. Essential oils typically protect a plant from disease (such as bacteria and fungus), repel dangerous bugs or other wildlife, and attract bees and other pollinators to help ensure survival of the species.

For humans, essential oils perform much the same functions. They can protect people from bacteria and fungus, repel unwanted bugs, and produce pleasant aromas. Science and experience have also found that essential oils affect your mood and many bodily organs.

Essential oils are usually steam-distilled from parts of a plant. The essential oils are natural mixtures of organic compounds. Each compound, separately, has unique properties that benefit plants and humans.

Essential oils are extracted from roots, leaves, buds, flowers, seeds, fruit, wood, twigs and the bark of plants. The extracted essential oils are highly concentrated. Before use, essential oils are normally mixed with a “carrier” oil such as sweet almond oil, coconut oil or olive oil to dilute the essential oil.

Over 3000 different essential oils are known, but, only about 300 have commercial importance. They are primarily used in the flavors and fragrances market.

Essential oils are often slippery like oil. And they contain the essence of the odor and flavor of the plant. Hence the name essential oil.

Compounds Make the Difference Between Essential Oils

Each essential oil is composed of a number of organic compounds. The difference between essential oils is the various compounds that are present and how much of each compound is found in each essential oil.

Essential oils are organic mixtures of low molecular weight chemical compounds. They are typically extracted from plants by steam distillation, though sometimes various solvents are used to recover the oils. The most important types of compounds are terpenoids and phenylpropanoids which supply the smell and biological properties to the oils.

The compounds can be detected with scientific instruments like a gas chromatograph or mass spectrometer. Some of the compounds found in essential oils are listed below.

α-bergamotene
bicyclogermacrene
borneol
bornyl acetate
bicyclogermacrene
β-bisabolene
γ-bisabolene
α-bisabolol
β-cadinene
cadinol, epi-α
α-cadinol
calamennene
camphene
camphor
δ-3-carene
carvacrol
β-caryohpyllene
caryophyllene oxide
1,8,cineole
α-copaene
β-cubebene
p-cymene
decanol acetate
estragol
trans-dihydrocarvone
β-eudesmol
fenchone
geraniol
cis-geraniol
geranyl acetate
germacrene D
α-humulene
linalool
linalool acetate
linalyl acetate
limonene
p-menth-2-en-1-ol
methyl eugenol
γ-muurolene
myrcene
neryl acetate
3-octanol
octanol acetate
3-octanone
octen-3-ol
octen-3-yl acetate
cis-β-ocimene
cis-ocimene
trans-ocimene
β-phellandrene
phenylacetaldehyde
α-pinene
β-pinene
cis-pinene hydrate
trans-piperitol
sabinene
β-selinene
spathulenol
α-terminene
γ-terpine
γ-terpinene
terpin-1-o
1 terpine-2-ol
terpin-4-o
α-terpinene
α-terpineol
terpinene4-0ol
terpinolene
α-thujene
thymol
verbenone
viridiflorol

These compounds are of interest to scientists who have studied their properties. But, what’s important for us is what specific compounds make up each essential oil. For, example, the major components (comprising > 1%) of peppermint essential oil are:

Compound Percentage
Menthone 33.34%
Menthol 29.54%
Isomenthone 7.58%
1,8-Cineol 6.99%
Menthyl acetate 3.17%
beta-Caryophyllene 2.34%
Limonene 2.00%
Caryophyllene oxide 1.76%
Menthofurane 1.63%
β-Pinene 1.4%
α-Pinene 1.11%
trans-Sapinen hydrate 1.01%

So, it becomes clear that only a few of the most prevalent compounds are really important and have a significant effect in peppermint essential oil.

Most often, several of the organic compounds in an essential oil work together to maximize the effectiveness. Many times the biological activity of the oil cannot be attributed to any of the compounds working alone. An example would be rosemary oil’s effect against insect larvae while the individual compounds have littler or no effect.

And, you should know that the exact amounts of each compound in an essential oil vary depending of the source. Differences may be caused by different climates, seasons of cultivation, soil nutrients, or methods of preparation. In addition, the different parts of a plant (roots, stems, leaves, fruits, flowers and fruit-peels) have different chemical components.

Here are the analysis results from four samples obtained from four commercial sources:

Compound Source 1 Source 2 Source 3 Source 4
Menthone 27.9% 21.2% 27.2% 18.4%
Menthol 27.5% 42.3% 39.9% 34.6%
Isomenthone 3.5% 2.9% 3.8% 2.9%
1,8-Cineol 5.3% 4.0% 3.4% 4.0%
β-Caryophyllene 4.2% 1.8% 1.6% 1.5%
Limonene 1.9% 1.3% 1.0% 2.1%
Pulegone 6.4% 1.0% 1.9% 14.4%
Menthofuran 5.5% 3.8% 1.3% 3.2%
Terpinen-4-ol 1.2% 3.4% 3.8% 2.1%
α-Terpinoll/borneol 6.4% 1.6% 1.7% 0.7%
Linalool 2.5% 4.4% 4.18% 4.8%

So, we must understand that essential oils are not “standardized.” They come from real living plants that react to the environment around them. When you find an essential oil that helps you, continue to obtain it from the same source to help ensure uniform results.

Scientists continue to study essential oils in a variety of clinical trails. For example, 48 studies are currently ongoing or preparing to start. Some of these studies include:

Significant research continues on essential oils in spite of lack of funding by pharmaceutical companies which cannot patent and profit from natural substances.

References

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