Animated Helpers: A reminder
Many animated helpers, like Jerry, the tour guide, are on this journey. If they block your ability to move forward in a lesson, hover over the animated figure with your cursor until an x appears. Press the x, and the helper will temporarily disappear. You may get the animated helper back by pressing the refresh button at the top of your screen. Also, the helper sometimes talks when you are trying to watch a video or read. If you hover over the character, a mute button will appear. Press the mute symbol, and the animation will stop speaking. Press it again to resume its speech.
Orientation–
First, could you listen to your animated helper tell you about this lesson? They will always be the ones who orient you.
Then, head to the Ship’s Projection Room, where Robert will hold this class.
When you get settled, read the material on the page and look at the pictures.
Watch Robert’s video on chemistry and make notes. Merlin the Magician has a short video to share his approach to chemistry. At the end of the page, there is also an animated video about Aromatic Chemistry personalities.
The videos may have different material than the write-ups. Taking notes is worthwhile.
Please study the aromatic chemicals in this lesson and take breaks whenever you need them.
Finally, could you download the Journal/Workbook and chart at the bottom of the page and do the exercises?
Setting a Comfortable Pace
Remember, some lessons are very comprehensive. Please break them down into chunks that allow you to work at your own pace.
Explore the Wizard Behind the Curtain.
Learn the Science and The Makeup of Essential Oils.
See what happens chemically when you use essential oils. Chemistry provides part of the scientific proof of how essential oils work. It also illuminates the similar traits of oils in certain families. When you can see the chemistry of an essential oil, you will always have a hint at its purpose—disinfecting, anti-inflammatory, cooling, irritating, etc.
THE CHEMISTRY OF ESSENTIAL OILS
Chemistry makes an excellent handmaid but the worst possible mistress.
STEPHEN BUHNER
Essential oils are composed of terpenoids and non-terpenoid hydrocarbons. The basic combination of carbon and hydrogen is a framework for attaching oxygen, nitrogen and other molecules to form unique oils and scents. Each molecule must be looked at in its whole form and not just as a functional group.
Thanks to Pierre Franchomme’s work, essential oil molecules can be viewed for their ability to attract or donate electrons. They also have an affinity for lipids (fats) or water, helping define their activity.
When the properties of the essential oils are discussed, we do not advise internal use, as these can be toxic to some oils. However, it is fascinating to note the applications.
If you think of a square box, the upper part defines compounds that give off electrons. For example, citral (an aldehyde) is in the upper part of the box and is on the left side because of its hydrophilic water-loving properties. Thymol, from thyme, is found on the same left side but produces a current that suggests the uptake of an electron.
As we will see below, monoterpenes, monoterpene alcohols, and phenols take up electrons and are stimulating. Ketones, aldehydes, esters, and some unsaturated sesquiterpenes give up electrons.
The Chemistry of Essential Oils Video
with Robert Rogers
TERPENES
The largest class of compounds are terpenes, made up of isoprene molecules or units.
Monoterpenes are the simplest, comprising two isoprenes or ten carbon units. Sesquiterpenes have 15 carbon units, and diterpenes have 20.
Terpenes can be acyclic, meaning they are linear. An example is alpha or beta-myrcene. Or cyclic, as in a ring, such as p-cymene. If two rings are joined, you have a bicyclic terpene like thujane.
Note that terpenes end in–ene.
Monoterpenes are commonly found in citrus peels and conifer needles. The cyclic form of monoterpene D-limonene is called limonene. Many books drop the D-enantiomer and call it limonene. Monoterpenes evaporate quickly, often called “top notes” in perfume blending. They also degrade or oxidize quickly. For example, D-limonene becomes a skin irritant when exposed to light, heat, and oxygen.
L-limonene is found in pine and spearmint oil.
Both d- and l-limonene increase systolic blood pressure, but only the d-form creates subjective alertness and restlessness.
Limonene from citrus and dillweed, alpha and beta-pinene from conifer needles, and ocimene from basil are some basic examples.
Myrcene and para-cymene are analgesics.
Energetically, the terpenes are placed in the bottom right corner of a chart that defines placement based on hot, cold, wet and dry properties.
All monoterpenes are antiseptic and disinfecting, general tonics with stimulating effects.
They are psychologically uplifting. Studies have found that limonene and alpha-pinene possess anti-tumor properties. In one study, limonene was found to dissolve gallstones.
Limonene has been found to relieve heartburn and gastric esophageal reflux disease (GERD) because it neutralizes gastric acid and supports peristalsis. Alpha-pinene is also found in cardamom essential oil.
Monoterpenes have hormone-like activity and act on the hypothalamic/pituitary/adrenal axis (HPAA), increasing or decreasing production.
The aroma of various citrus oils varies widely because of minor constituents. Lemon oil is comprised mainly of limonene, but its 3.5% citral gives it the characteristic scent.
Grapefruit oil contains 90% monoterpenes, but the aroma comes from trace amounts of nootkatone (C15 ketone) and paramenthenthiol. Another citrus fruit oil, from mandarin, is also 90% monoterpenes but derives its scent from methyl anthranilate, which gives it a calming effect. Sweet orange is similar but has traces of the aldehyde sinensal and other minor compounds to provide its characteristic aroma.
Sesquiterpenes are less volatile than monoterpenes and often have more pungent odours. They are in the top right quadrant of an energetic chart, with more cooling and dry qualities. Because of their smaller molecules, they are more viscous and often have a yellow or darker colour than the monoterpenes.
They are strongly anti-inflammatory with some anti-bacterial properties. They can help to counter histaminic reactions.
They also oxidize over time, but with patchouli, the odour improves.
One exciting and well-known sesquiterpene, chamazulene, possesses only 14 carbon atoms but is included in the class. It is found in German chamomile and yarrow essential oils and gives a deep, dark blue colour.
Other examples of sesquiterpenes are beta-caryophyllene, found in ylang-ylang, and a-bisabolene, found in black pepper.
Alpha-farnesene, from eucalyptus, may be effective against the bacterial biofilm associated with dental decay. Please don’t drink eucalyptus under any circumstances. Only 3 mls taken internally is fatal to children. Farnesene also possesses hormonal influence.
Another example is alpha-zingiberene, which possesses antioxidant activity, reduces inflammation and increases glutathione production.
Diterpenes are giant, heavy 20-atom molecules. They have a high boiling point and often need more after steam distillation.
They are often present in resins, such as alpha camphorene. Sclareol, found in clary sage oil, is another example.
ALCOHOLS
Terpene or monoterpene alcohols (terpenols) are widely found in essential oils. Their names end in –ol.
They have a hydroxyl (OH) group attached to one of the carbon atoms.
Monoterpenols are antiseptic and have antibacterial, antifungal, and antiviral properties.
They can be soothing or uplifting and are found in the bottom left quadrant of energetic essential oil charts. They are stimulating and wet.
Essential oils containing these compounds are suitable for everyday use and are gentle on the skin.
Terpinen-4-ol, found in tea tree oil, is antiseptic, while l-linalool from lavender is more sedative. The former is effective against multi-drug resistant Staphylococcus aureus (MRSA) and resistant Pseudomonas species. It has also been found to prevent the influenza virus from entering host cells by disrupting viral membrane integrity.
The compound has also been found to inhibit the growth of melanoma cells.
Oils that contain a high level of monoterpenols are generally safe for the skin, even undiluted. Geraniol, found in a high percentage in palmarosa, does not irritate in neat doses. It has been found effective against Escherichia coli (E. coli) and possesses antitumour and anti-cancer activity.
Dear Pleasure Cruise and Apprentice Ship Adventurers-
There are many riches for you to explore on this journey. Be sure to do just what is necessary, but instead, set a pace that is just right for your lifestyle. Take breaks when you need them!
Linalool, found in basil and lavender, is soothing and anti-spasmodic. Other linalool oils are coriander, ho leaf, petitgrain, and thyme’s chemotype linalool.
Menthol, from the mint family, is another monoterpenol.
Sesquiterpenols or sesquiterpene alcohols have several uses. One of the better-known is alpha-bisabolol, found in German chamomile. It possesses anti-inflammatory properties and anodyne activity.
Nerolidol is present in Melaleuca quinquenervia. It has been found to enhance the activity of 0.5% tea tree oil against hair lice nits.
Sclareol, found in clary sage, and patchoulol in patchouli essential oil are other examples.
Santalol from sandalwood is another calming constituent that tones the heart.
Sesquiterpene alcohols tone the nerves and muscles and reduce congestion in the venous and lymphatic systems. Cedrol, found in Atlas Cedar, is a venous tonic. Carotol from carrot seed oil stimulates liver cell regeneration.
Video-Merlin on Chemistry
PHENOLS
Phenols, sometimes known as phenolic terpenes, are found in the bottom left corner of energetic essential oil charts. They are hot and wet.
They are formed by adding a hydroxyl group to one of the six carbon atoms of a benzene ring.
Like alcohols, their names end in –ol, but that is where any comparison ends.
Phenols are common in nature, including adrenaline and THC from marijuana.
Thymol and carvacrol are the two significant phenols in thyme, oregano, and other aggressive essential oils. Another example is Eugenol (the picture below) from clove bud and holy basil.
Summer and winter savoury are also phenols.
Be cautious when using phenols, as they can irritate the skin and mucous membranes.
They are some of the most potent anti-bacterial compounds and stimulate the nervous and immune systems.
NOTE- Phenol, the synthetic compound, is a carcinogen derived from petroleum. They are not related.
ETHERS
Ethers, known as phenylpropanoids, can vary in their placement on the energetic chart.
Also known as phenylmethyl ethers or phenolic ethers, they contain either methyl or ethyl groups attached to a benzene ring via an oxygen molecule.
Anethole, apiol, eugenol, estragole, myristicin, and safrole are well-known ethers. Estragole, found in tarragon, is also known as methyl chavicol.
Anethole (anise) and methyl chavicol are in the middle of the energetic chart (wet/dry neutral) and lower because of their stimulating nature.
It should be noted that anise contains 97% anethole and, although anti-spasmodic, has a calming effect on the nervous system.
Trans-anethole from sweet fennel and myristicin from nutmeg are other examples. The latter has a similar structure to MMDA, a precursor to MDMA (ecstasy).
Some phenylpropenes, such as cinnamic aldehyde (cinnamon) and eugenol (clove bud), are placed on the lower part of the chart but to the far left due to their hydrophilic nature.
These are very aggressive and should never be used undiluted. They stimulate antibacterial activity and are skin irritants.
ALDEHYDES
Aldehydes are partially oxidized alcohols. At the end of the carbon chain, an oxygen atom is double-bonded to a carbon atom.
The fourth bond is always a hydrogen atom.
Aldehydes usually end in–al and possess calming, relaxing and sedative properties.
They are found in the top half of the chart and far left for their water-loving nature.
The anti-inflammatory effect is most noticeable when diluted and used in low concentrations by aerosol or carrier oil.
They are highly aromatic. Some examples include citral and citronellal in lemon balm, beta citronellal in lemongrass, geranial in Eucalyptus citriodora, and neral in lemon verbena.
.Geranial and neral are isomers with similar molecular structures, but the carboxyl molecule is placed differently.
Recent work suggests citronellal may increase olfactory sensitivity in Parkinson’s patients. Citral is anti-fungal and antiviral, especially for herpes virus outbreaks.
Cinnamaldehyde, a compound found in cinnamon, decreases muscle soreness after exercise and is antifungal and antimicrobial. This compound benefits type 2 diabetes by increasing insulin sensitivity.
ESTERS
Esters combine an acid and alcohol and are named accordingly—for example, acetic acid and linalool form linalyl acetate.
Acids are not found in essential oils but do find their way into hydrosols.
Esters end in –ate.
They are calming and antispasmodic, occupying the chart’s top right/centre part. They are slightly lipophilic (fat-loving) and give off an electron.
They tend to have a fruit-like odour. Linalyl acetate is found in lavender, clary sage, and bergamot, while geranyl acetate is found in sweet marjoram.
Roman chamomile comprises 85% esters of five carbon atoms and is a calming and soothing oil physiologically and psychologically.
Esters with seven carbon atoms are the most robust anti-spasmodic oils in ylang-ylang and petitgrain.
Esters are balancing and anti-spasmodic.
Esters of formic acid (one carbon atom) are found in geranium. Esters of acetic acid, known as acetates, are found in everlasting, rosemary (verbenone), laurel leaf and cardamom.
Geranyl acetate in sweet marjoram and geranium is helpful for fungal and yeast infections.
One exception is the compound methyl salicylate found in sweet birch. As we will learn, sweet birch is 98% methyl salicylate, a chemical that is readily synthesized in chemical labs. It is also found in wintergreen. Both should be used with extreme caution.
Methyl anthranilate found in mandarin peel essential oil possesses antiandrogenic potential, suggesting use in PCOS and even prostate cancer.
Bornyl acetate, from black spruce, is another example of an ester.
KETONES
Ketones are related to aldehydes and contain the carbonyl group. Both ketones and aldehydes are found in progesterone and testosterone molecules.
Ketones generally end in–one, except camphor. This substance has no relation to the camphor plant.
Ketones are resistant to metabolism and thus are not easily broken down by the liver and removed from the body.
D-pulegone, from European pennyroyal essential oil, is the most well-known toxic ketone due to a well-publicized death. A 23-year-old woman drank 15 ml of undiluted pennyroyal essential oil.
Some oils containing ketones are caraway, frankincense, hyssop, peppermint, rosemary, sage, wormwood, mugwort, and spearmint.
Some ketones are helpful to the skin, including jasmone (jasmine) and isomethone (geranium). D-carvone in spearmint, fenchone in sweet fennel, and verbenone in rosemary.
Note that carvone occurs in two enantiomers or mirror images. Imagine your hand in front of a mirror. It is the same hand but looks reversed.
R(-)-carvone (also known as L(-)-carvone smells like spearmint, while its mirror image S-(+)-carvone (D-carvone) smells like caraway.
Life Everlasting or Immortelle (Helichrysum italicum) oil contains two unusual ketones. These contribute to the very distinctive odour and its anti-hematoma properties. This makes it a remarkable oil, in combination with arnica carrier oil, for application to bruises and contusions.
Externally, ketones are strongly anti-viral, including herpes and human papillomaviruses.
Thujone from cedar is strongly anti-viral but also heals wounds and promotes the regeneration of new skin and mucosal tissue.
Ketones are also mucolytic, help attract moisture and soften, loosen and expectoratie mucus.
OXIDES
In chemistry, an oxide is an ether or peroxide. However, the term oxide is used because ethers (above) have different properties.
In aromatherapy, an oxide has an oxygen atom in a chain of carbons that forms a non-aromatic ring.
The most common oxide is cineole, a powerful expectorant. Both 1,4-cineole and 1,8-cineole are expected, with the latter known as eucalyptol. This is found in Eucalyptus globulus, Rosemary (R. officinalis CT cineole), and laurel leaf (Laurus nobilis).
Members of the eucalyptus and melaleuca genera are rich in oxides.
It is a possible anti-inflammatory for neurodegenerative conditions.
Rose oxide is found in geranium and rose. Linalol oxide found in Hyssopus officinalis var. decumbens has antiviral and expectorant effects, making it especially useful for bronchial infections.
LACTONES
Lactones are found mainly in expressed citrus peel oils and in jasmine absolute.
They are cyclic esters derived from lactic acid. They have an oxygen atom double-bonded to a carbon atom attached to another oxygen atom in a closed ring.
They tend to end in–lactone or -ine.
Although the amounts of lactone in total oil composition are low, they are believed to play an important role as mucolytics.
Alantolactone from elecampane shows activity against staphylococcus and some cancer cell lines.
The most well-known catnip ingredient is nepetalactone, a mosquito repellant and a feline attractant. We cut our cat Ceres off of catnip, as she has a severe addiction.
Coumarins are a subgroup of lactones. Umbelliferone, for example, is commonly found in many oils of the Umbelliferae family. Coumarin may have potential use in Alzheimer’s disease as an acetylcholinesterase inhibitor.
Conversely, furanocoumarins are found in many citrus peel oils, including bergamot, bitter orange, grapefruit, lemon, lime, and steam-distilled angelica root.
You can head down to the bottom of the page to access downloads and get your Chemistry notes from the Practical Potions Accompanying Journal.
Aromatic Chemistry- Animated Video