Introduction to Essential Oils: Chemotypes
Chemotypes: The aromatic oils found in plants are built from three basic elements: carbon, hydrogen and oxygen. Depending on the type of molecules they contain, volatile oils are classified into different chemical groups. These chemical groups are called chemotypes. Chemotypes are a phenomena of nature when plants from the same genus and species produce different aromatic molecules. The specific molecules produced by each plant are determined by genes and enzymes.
Phenols are the most stimulating, bactericidal and immune-modulating of all the aromatic groups. Phenols are usually irritating to the skin and toxic to the liver, and therefore should be used with caution and in low dilution for short periods of time. The oils in this group are clove, oregano, savory, and certain thymes.
Terpenes: Terpenes are antiseptic and stimulating and can be irritating to the skin in concentrated amounts. Essential oils in this group include lemon, orange, mastic, nutmeg, angelica, pine, black pepper and bergamot. A subgroup of terpenes is the sesquiterpenes and are mainly distilled from the root or wood of the plant and can contain anti-inflammatory, antiviral, antibacterial, analgesic, antispasmodic and sedative qualities. This group includes clove, rose, chamomile, tansy, yarrow, valerian and carrot seed.
Alcohols: This group contains essential oils that are toning, stimulating, antibacterial, antiviral, and are generally non-toxic. The oils in this group are geranium, ravensara, rosewood, rose, and tea tree. Others in this group that are anti-inflammatory and stimulate immune response are neroli, chamomile, carrot seed, sandalwood, vetiver, ginger, patchouli and rose.
Ketones: The action of ketones is mucolytic or dissolves mucous, wound healing, and dissolves fats. They are found in sage, hyssops, pennyroyal and thuja The are potentially toxic due to the possible epileptic, abortifacient and convulsive effects. Nontoxic oils in this group are jasmine fennel and to some extent peppermint.
Esters: These are the most balancing of all the chemical families of the essential oils. They are soothing and have anti-fungal and antispasmodic effects. They tend to smell nice and include lavender, bergamot, clary sage, ylang-ylnag, Roan chamomile and marjoram.
Ethers: Antispadmodic effects. Included in this group are basil, tarragon and cedar.
Oxides: Essential oils in this group are tea tree, naiouli, rosemary, cajeput, hyssop, bay laurel and eucalyptus. Within this group are potentially harmful toxic molecules found in wormseed oil and some peppermint if it was harvested during flowering season.
Aldehydes: These oils are anti-inflammatory, calming, antiseptic and sedating. They can be a bit irritating to the skin if used undiluted. They include the lemony plants like lemongrass, Melissa, lemon verbena, citronella, and eucalyptus citriodora
Coumarins: Are potentially toxic and can cause liver damage or photosensitivity. They are also blood thinners and should be used with caution. The oils are bergamot, ammi visnaga, angelica, citruses and to some extent, lavender.
Acids: Some of the essential ils contains acids but they are primarily found in hydrosols. They are anti-inflammatory, antiseptic and moisturizing.
Each plant is comprised of specific chemicals that are classified in the above major groups. Because we know the effect these specific chemicals have on the body we can do a reverse application when choosing an oil. For example, caryophyllen, a chemical in the terpene group, is a constituent found in clove therefore we know that clove is anti-inflammatory and antiviral. If we've identified a situation that warrants the application of an anti-viral agent then we may consider clove.
Understanding the classification of essential oils is critical when using them therapeutically. Proper applications and safety guidelines must be understood due to the potential of a such a concentrated substance to induce harm when in direct contact with delicate mucous membranes found in the digestive tract and other sensitive tissues such as those in the nasal passages, vagina and lungs. Tomorrow we will start to explore methods of application and proper dilution when using essential oils for promoting health and well being.