Making up one of the largest family of chemical compounds, herbalists and apothecaries alike use terpenes in compounding remedies and medicine.
Isoprene is a five carbon long molecule that is the basis of all terpenes. Think of each five carbon isoprene as a single chain link. Terpenes are constructed of these chain links, such that most terpenes are 5, 10, 15, up to 40 carbons long. Limonene and Linalool are both ten carbons long, or contain two isoprene chain links, whereas Phytol, being a larger more oily molecule, contains 20 carbons or 4 isoprene links.
Any given terpene can be found to exist in an incredible variety of different plants. For instance, ß-Caryophyllene is found in black pepper, cloves, some cannabis Sativa strains, rosemary and hops.
Cannabinoids were initially believed to only exist in family Cannabaceae, but have since been found in other families of plants such as family Linaceae (Flax), and Asteraceae (Echinacea and Helichrysum). Not surprisingly, the heated/vapourised smoke of cannabis contains up to 50% terpenes, with cannabinoids accounting for 10-20% and the other terpenes accounting for another 10-30%.
In most cases, the larger the terpene molecule, the more viscous and less vaporous it is. Limonene evaporates very quickly, with a pungent fragrance: similar to acetone. Cannabinoids, on the other hand, are much larger molecules, are nearly solid at room temperature and have only a faint odour: similar to pine pitch. The size and structure of the terpene also determine factors such as how soluble it is in water, ethyl alcohol, oil, or other solvents, how easily it decomposes from heat, light and air, along with many other factors.
How plants use terpenes
Plants use terpenes in several ways. Individual fragrant terpenes attract bees and other animals that carry the plant’s pollen to other plants; this is not the case for cannabis since its pollen is carried in the wind. Other terpenes are utilised defensively, either as an irritating warning to drive away herbivores that would eat the plant, or to attract predators of the herbivore. After hundreds of millions of years of evolutionary refinement of terpenes in plants, it’s no wonder that humans are so strongly attracted to some terpenes and repulsed by others.
Citronellol is a monoterpenoid found in roses, commonly used as a concentrated oil in perfumes.
Limonene can create different odours from the original three, though this is dependent on the ratio and amounts used. More than any other industry, the perfume industry is well versed in these facts and has researched and documented similarities and differences between terpenes.
Each terpene has many medical benefits which give rise to overlapping synergies between them. Herbalists are well aware of this. By deliberately overlapping these benefits treatment has a much better chance at success.
Myrcene is also found often in the highest concentrations. Myrcene is found in large amounts in hops, aged mango, bay leaves, and lemongrass. The odour varies but is described to have an herbal, balsamic, rooty, and spicy aroma. Its medicinal properties are well known, particularly used to treat pain and inflammation. Myrcene is known to have a calming effect both mentally and physically, which is why it has been used to treat psychosis and muscle spasms. The properties it encompasses has synergistic effects with other terpenes, like THC for pain, THC-A for inflammation, CBD and Linalool as an antipsychotic. Myrcene, THC, THC-A and CBD together treat muscle spasms.
The second most abundant terpene in cannabis are the Limonenes
Limonenes are terpenes found in the peel of citrus fruit, as well as in other fruits and flowers. Wearing a sweet, fresh fruity odour: the citrus aroma is unmistakable. Limonenes carry benefits including antidepressant, anxiety-relief, immuno-stimulant (similar to garlic), antitumour, and bacterial / anti-fungal properties. Limonenes aid in treating gastric reflux and treat oesophagal ulcers.
Limonenes can be used topically as an antiseptic agent and are quite effective to repel insects: the leaves of the lemon or grapefruit tree are used for this purpose. Limonenes have synergies with THC-A, CBD-A, CBC-A, CBC, CBC, CBG, Caryophyllene-Oxide, and Linalool.
The medicinal value of Phytol
Phytol is another interesting terpene, different from most others, offering yet other medicinal options to a patient. Phytol is one of the breakdown products of decomposed chlorophyll. Its aroma is floral and balsamic in nature. It is an immunosuppressant and impedes the activity of Aflatoxin (a mycotoxin) in the body. It is used as a topical to reduce itching (thereby reducing the urge to scratch) and to treat slow-healing tissue wounds. Phytol is a non-toxic yellow pigment suitable for dying foodstuffs.
Terpenes are utilised in many commercial products that we come into contact with daily such the fragrances in the air, cosmetics (as solvents and scents), medicine, candy, breakfast cereal and even in air fresheners. Their anti-bacterial/fungal abilities are used as preservatives and stabilisers.