Essential Oils are concentrated forms of plants. To understand why any given essential oil effects change, it is important to understand the chemical compounds that make up each plant. Plants contain hundreds of identifiable chemical compounds. One of the most important classes of chemical compounds is called terpenes. Here we’ll break down what they are.
Terpenes are a large and diverse class of organic compounds produced by a variety of plants, particularly conifers, and by some insects. They are often strong-smelling and protect the plants that produce them by deterring herbivores and by attracting predators and parasites of herbivores. Terpenes are the primary constituents of the essential oils of many types of plants and flowers.
Structural Diversity
Chemically, terpenes are hydrocarbons, derived from the basic molecular formula (C5H8)_n, where n is the number of linked isoprene units. This isoprene rule is the basis for the classification of terpenes. Depending on the number and the nature of the rearrangement of their isoprene units, terpenes can be classified into various groups:
- Monoterpenes: made of two isoprene units and have the molecular formula C10H16. Example: limonene, found in citrus fruit peel.
- Sesquiterpenes: consist of three isoprene units and have the formula C15H24. Example: caryophyllene, found in black pepper.
- Diterpenes: composed of four isoprene units; they have the molecular formula C20H32. Example: phytol, a constituent of chlorophyll.
- Triterpenes: made up of six isoprene units. Example: squalene, a precursor to steroids.
- Tetraterpenes: contain eight isoprene units and include carotenoids such as beta-carotene.
Functional Roles
In nature, terpenes have a vast array of functions:
- Defense Mechanisms: As mentioned, many terpenes can repel insects and animal grazers and can also attract the predators and parasites of these herbivores.
- Attractants: Terpenes are responsible for the aroma of many plants and flowers, and they can attract pollinators like bees, butterflies, and hummingbirds.
- Building Blocks: Some terpenes are precursors to certain important compounds such as vitamins, pigments, and steroids.
Applications
Beyond their natural roles in plant life, terpenes have been found to have a variety of uses in human industry including:
- Aromatherapy: exploiting the fragrant properties of terpenes for psychological and physical well-being.
- Flavoring: enhancing flavors in food and beverages.
- Perfumery: as fragrances in perfumes and personal care products.
- Medicine: some terpenes are being researched for their potential therapeutic effects.
Human interest in terpenes has been growing due to their versatility and their potential benefits, stimulating much research in the field of organic chemistry and pharmacology.
Top Ten Beneficial Terpenes and Their Attributes
Here is a list of some more common terpenes, where they come from, and some common uses.
1. Limonene
Pleasantly Citrus-Scented, Elevates Mood
Limonene is renowned for its bright citrus aroma, prevalent in the peels of oranges and lemons. Believed to have uplifting and stress-relieving effects, limonene is a favorite in both aromatherapy and household cleaning products for its refreshing scent.
2. Caryophyllene
Spicy Note, Gastroprotective Properties
Found in black pepper, cloves, and cinnamon, caryophyllene offers a warm, spicy note and is unique for its ability to interact with the endocannabinoid system, possibly aiding in reducing inflammation and offering gastroprotective benefits.
3. Myrcene
Earthy Fragrance, Enhances Relaxation
Myrcene, with its musky, earthy fragrance reminiscent of ripe mangoes, is said to help in relaxation and has sedative properties. It is one of the most abundant terpenes in cannabis and widely used in the perfume industry.
4. Pinene
Refreshing Pine, Aids Memory
As the name suggests, pinene has the fresh scent of pine and finds its way into numerous cleaning products and air fresheners. It’s being studied for its potential to aid memory retention and respiratory health.
5. Linalool
Floral Lavender, Calms the Nerves
Linalool boasts a delicate floral scent, primarily associated with lavender, known for its calming effects on the nervous system. It’s also used in many skin care products for its anti-inflammatory properties.
6. Humulene
Woody and Earthy, Anti-Inflammatory
Humulene imparts a subtle, earthy aroma found in hops and coriander. Valued for its anti-inflammatory and appetite-suppressing properties, humulene is the subject of research for various therapeutic applications.
7. Terpinolene
Piney and Herbal, Antioxidant Effects
Terpinolene combines scents of pine, herbs, and floral, with a hint of citrus. Found in tea tree, nutmeg, and conifers, it’s reputed for its antioxidant effects and is being researched for its potential to reduce the risk of various diseases.
8. Eucalyptol
Eucalyptus Refreshment, Respiratory Relief
Also known as cineole, eucalyptol is the primary component of eucalyptus oil and is recognized for its minty, cooling qualities. It’s used in various respiratory remedies and may have potential memory-enhancing properties.
9. Geraniol
Sweet Rose-Like, Natural Insect Repellent
Geraniol, with a sweet, rose-like aroma, is found in geraniums and used in flavoring and perfumery. Beyond its fragrant profile, geraniol is studied for its effectiveness as a natural insect repellent.
10. Bisabolol
Delicate Chamomile, Skin Healing
Present in chamomile and candeia trees, bisabolol is known for its delicate, sweet aroma. It has been used in cosmetics for its skin-healing properties, including anti-irritation and anti-inflammatory effects.
