Terpenes represent a wide variety of hydrocarbons produced by a large number of plants and some insects. They are the main components of any resin or essential oil plant and play an important role in the plant kingdom, from discouraging insect predation to protecting against environmental stress, to building more complex chemical building blocks such as cannabinoids, certain hormones, vitamin A, pigments and sterols.
Generally , Terpenoids contribute to the smell of eucalyptus, the scent of cinnamon, cloves, ginger and the color of yellow flowers. The best-known terpenoids include citral (the main constituent of citronella oil), menthol and also cannabinoids.
Terpenoid plants are widely used for their aromatic qualities. They play also a role in traditional herbal remedies and are currently under scientific scrutiny to confirm their antibacterial or antineoplastic properties (which prevents or inhibits the development of a tumor).
In fact , the cannabis plant contains various components. However , about 140 of them belong to a broad class of aromatic organic hydrocarbons called terpenes. Some people confuse terpenes with terpenoids. The main difference between terpenes and terpenoids is that terpenes are hydrocarbons (composed only of carbon and hydrogen), whereas terpenoids are oxidized or chemically modified.
Terpenes are synthesized in cannabis by secretory cells within glandular trichomes. Their production indeed increases with exposure to light. These terpenes are mainly observed in high concentrations on the flowers of female plants not fertilized before senescence. The essential oil is extracted from the plant by distillation or vaporization. Most terpenes vaporize at a temperature similar to that of THC (which boils at 157°C), but some terpenes are more volatile than others. Terpenes also play an important role in providing the plant with a natural means of protection against bacteria and fungi, insects and various environmental stresses.
Basically ,Cannabis can affect the mind, emotions, and behavior. Therefore, the main psychotropic cannabinoid, delta-9-tetrahydrocannabinol (THC), has been extensively studied. However, most other cannabinoids, terpenoids, and flavonoids in cannabis play a large role in the effects of cannabis and remain under-studied.
So ,Terpenes are the main constituents of aromas and odors. They act on receptors, the neurotransmitters. In addition , they combine or dissolve in lipids or fats. They also act as inhibitors of serotonin reuptake, improve norepinephrine activity, increase dopamine activity and increase GABA, a neurotransmitter that inhibits the nervous system. However, more research is needed to clarify how cannabis terpenes can be used medically to treat certain symptoms or conditions.
The Carlini study showed that there may be potentiation of the effects of THC by other substances present in cannabis. So , the double-blind study found that cannabis with equivalent or higher levels of CBD and CBN relative to THC would induce effects two to four times greater than expected with THC alone. The effects of using twice the amount of cannabis of a THC-only variety were no different from those of placebo.
This suggestion was reinforced by a study by Wilkinson which sought to determine whether there was an advantage in using cannabis extracts compared to THC alone. A standardized cannabis extract consisting of THC, CBD and CBN (SCE), one pure THC, and one without THC but with CBD, was tested on mice with multiple sclerosis and a rat with epilepsy.
In the epileptic model, ECS was more potent and also acted faster than THC alone. CBD also showed anticonvulsant activity. CBD did not prevent seizures and did not modulate THC activity.
Therefore, for certain actions of cannabis (e.g. anti-spasticity), THC was the active constituent, which can be modified by the presence of other components. However, for other effects (e.g. anticonvulsant properties), THC, although active, may not be necessary for the effect observed. Above all, these results have shown that not all therapeutic actions of cannabis are due to THC.
Dr. Ethan Russo later supported this theory with scientific evidence by demonstrating that non-cannabinoid components such as terpenes served as inhibitors to the intoxicating effects of THC while increasing the therapeutic potential of THC. This “terpenophytocannabinoid synergy” increases the potential of cannabis extracts to treat pain, inflammation, bacterial and fungal infections, depression, anxiety, addiction, epilepsy or even cancer.
The medical and recreational uses of cannabis are known, but the most subtle aspect of the plant, its smell, is largely unknown. In fact , the aromatic herbs we use in cooking are made up of special terpenes that give them a distinct smell. Cannabis is so complex from this point of view that the combinations of terpenes are limitless, creating an infinite spectrum of aromas and fragrances. But this also explains why some varieties of cannabis have smells similar to well-known fruits or essences (pine, blueberry, lemon, etc.).
Terpenes, however, are more than just the smell. Many terpenes act synergistically, and some act as catalysts or inhibitors for other compounds in the plant. So ,understanding the role of certain terpenes will allow scientists to manipulate cannabinoid levels. For example ,certain terpenes are thought to modulate the psychoactive and physiological effects of cannabis.
For example, cannabis contains a certain amount of a terpene called caryophyllene (BCP) that contributes to the aroma and scent of the plant. Early studies show that this terpene, which is also found in other legal herbs such as black pepper (plays on the spiciness of the pepper), activates CB2 receptors and acts as a non-psychoactive anti-inflammatory. Because it is bound to a cannabinoid receptor, and because caryophyllene is present in foods approved by the FDA (the US food regulatory authority), BCP is the first dietary cannabinoid.
Further studies are needed, however, to find out how all these substances contribute to the medicinal properties of cannabis.
What are flavonoids?
Flavonoids are one of the largest families of nutrients known to scientists and include more than 6,000 identified members. About 20 of them, including apigenin, quercetin, cannflavin A and cannflavin B (found only in cannabis), β-sitosterol, vitexin, isovitexin, kaempferol, luteolin, and orientin have been identified in cannabis. Flavonoids are known for their antioxidant and anti-inflammatory properties, as well as for their contribution to the colors of the food we eat (blueberry blue or raspberry pink).
Some flavonoids extracted from cannabis have been studied for their pharmacological effects. Initial findings are promising, but more research is needed to fully understand the role of flavonoids in the medical use of cannabis, in particular how they interact with cannabinoids, either synergistically increasing or decreasing.
The terpene wheel
Generally ,Terpenes are essential for the manufacture of pigments, sterols, hormones, and even plant cannabinoids. Terpenes are also responsible for the pleasant or unpleasant odors of cannabis and its physiological effects. Cannabis users often ask to smell the weed before choosing it. The smell can identify to some extent the variety of cannabis, and thus its effects.
As the Casano study showed, cannabis varieties differ greatly from one variety to another, and even from one crop to another. Varieties with a high concentration of very specific terpenes are more identifiable by smell than others.
Varieties with musk or clove scents thus deliver more sedative and relaxing effects, due to their high levels of myrcene. Varieties with a more pine scent tend to act more on the mind and memory (terpene pinene). And lemon aromas promote good mood (limonene).
Myrcene, and specifically β-myrcene, is a monoterpene and the most common terpene produced by cannabis. Its aroma , therefore, is described as musky, earthy, grassy, almost clove-like. A high level of myrcene (above 0.5%) causes a “couch-lock” effect, typical of Indica strains. Myrcene can be found in hop oil, lemon fruits, berry leaves, eucalyptus, wild thyme, lemongrass…
It has also specific medicinal properties, including lowering the barriers between the blood and the brain, allowing many compounds, including cannabinoids, to act more quickly. Myrcene also causes maximum saturation levels of the CB1 receptor to increase, promoting psychoactive effects.
Moreover , Myrcene has analgesic, anti-inflammatory, antibiotic and antimutagenic properties. It blocks the action of certain carcinogens such as cytochrome or aflatoxin B.
As myrcene exist in lemon fruit essential oils, legend has it that eating a mango 45 minutes before consuming cannabis increases the effects of the latter. Above all, the mango must be ripe for myrcene levels to make a difference.
As its name suggests, pinene has pine or fire aromas. Basically ,it exist in 2 forms: α-pinene and β-pinene, both of which are constituents of pine resin. α-pinene is most often found as a terpenoid in nature.
Pinene can also present in balsamic resins, pinewood and lemon fruits. Both pine isomers are the main ingredient of turpentine. It tends to react with other chemical compounds, forming a variety of other terpenes such as limonene and other compounds.
Pinene serves medicinally to act both as an anti-inflammatory, expectorant, bronchodilator, as well as a topical antiseptic. α-pinene has shown anticancer properties and has been used for this purpose in traditional Chinese medicine for years. The effects of THC could also be lessened with pinene.
Limonene is a monocyclic monoterpene also one of the 2 main terpenes formed from pinene. As its name suggests, cannabis varieties with high limonene content have a strong citrusy odor. They generally produce a good mood. This lemon terpene is the main constituent of citrus peel, rosemary, juniper or peppermint, and several pine needles oils.
Limonene is easily absorbed by inhalation and passes quickly into the bloodstream. In addition , it helps other terpenes absorption via the skin and any other corporal tissues. Limonene inhibits the growth of many species of fungi and bacteria, making it particularly effective for infections such as plantar fungi. It is also believed to promote weight loss.
Botanicals use limonene like a traditional pesticide in order to repel pests. Limonene was originally used in cooking and perfumes.
Beta-caryophyllene is a sesquiterpene usually found in Thai basil, cloves, cinnamon leaves, and black pepper, and small amounts in lavender. Its aroma flavor characterized either as peppery, spicy and/or woody. Caryophyllene is the only terpene which interact with the endocannabinoid system (CB2-R).
In fact ,several studies have focused on the effects of caryophyllene. Fine/Rosenfeld has shown that in combination with other phytocannabinoids, notably cannabidiol (CBD), when ingested orally, it shows promise in the treatment of chronic pain.
The Horváth study suggests that β-caryophyllene is an excellent therapeutic agent to prevent nephrotoxicity caused by chemotherapy.
The Jeena, Liju, study looked at black pepper extracts, which showed antioxidant, anti-inflammatory and antinociceptive properties. Varieties of cannabis containing caryophyllene could, therefore, be efficient to treat arthritis or neuropathic pain.
Linalool is a non-cyclic monoterpenoid with floral and lavender scents. Therefore, cannabis strains loaded with linalool bring calm and relaxation.
Linalool has been used for centuries to help sleep. Linalool soothes anxiety caused by THC, making it also useful in the treatment of psychosis and anxiety. Studies also suggest that linalool boosts the immune system, significantly reduces inflammation in the lungs and can restore emotional and cognitive functions (in the treatment of Alzheimer’s for example).
Linalool has been isolated from several hundred plants, such as mint, laurel, cinnamon, rosewood… Although technically they are not plants, some fungi also produce linalool.
So , Linalool is a critical precursor for the formation of vitamin E.
Terpinolene is a common compound of sage and rosemary. It is widely used in soaps and perfumes, and also scares off insects. Terpinolene has pine aromas, with hints of flowers and herbs.
Terpinolene is a central nervous system depressant, which induces drowsiness or sleep or reduce psychological arousal or anxiety. Also, terpinolene believed to significantly reduce the expression of the AKT1 protein in K562 cells and inhibit the proliferation of cancer cells.
Camphene is a monoterpene that emits the scent of damp forest and fir needle. It may therefore, play an important role in cardiovascular disease.
The Vallianou study showed that camphene reduced plasma cholesterol and triglycerides in overweight rats. In fact , overweight is one of the main causes of heart attacks. Camphene could, therefore, used as a lipid-lowering agent.
It exists in camphor oil, turpentine, lemongrass oil or ginger oil. It also used in cooking to add flavor. Moreover , it is produced industrially by catalytic isomerization of α-pinene.
The α-terpineol, terpinen-4-ol, and 4-terpineol are 3 closely related monoterpenes. The aroma of terpineol is indeed similar to the smell of Lilac flowers. Terpineol generally observed in varieties with high levels of pinene, which masks the smell of terpineol.
Terpineol, and in particular α-terpineol, is famous with calming and relaxing effects. It has also shown some antibiotic, antioxidant and antimalarial properties.
Phellandrene generally described as having a peppermint odor with a slight lemon return. It is uses in traditional Chinese medicine to treat digestive disorders. It is the main ingredient in turmeric leaf oil, in order to prevent and treat systemic fungal infections.
Phellandrene is probably the easiest terpene to identify in the laboratory. When a solution of phellandrene in a solvent is treated with a concentrated solution of sodium nitrate and a few drops of acetic acid, large crystals of phellandrene nitrate form.
Phellandrene was first discovered in eucalyptus oil. However, it exists in many herbs and spices, including cinnamon, garlic, dill, ginger, and parsley. The recognizable odors of some essential oils depend almost entirely on the presence of phellandrene.
Delta-3-carene is a bicyclic monoterpene with a sweet and pungent smell. It is naturally exist in cypress, juniper and fir oil. At high concentrations, Δ³-carene can be a central nervous system depressant. It is often efficient to dry out excess body fluids, such as tears, musk or sweat.
Carene is non-toxic but can irritate when inhaled. Cannabis varieties with a lot of hulling could potentially cause coughing or itchy throats.
Humulene is a sesquiterpene present in hops, Cannabis Sativa varieties or Vietnamese coriander. It is also what gives the hoppy aroma to beer.
Humulene considered to be anti-tumoral, anti-bacterial, anti-inflammatory and an anorexic (it limits appetite). It has commonly mixed with caryophyllene and used as a remedy for inflammation.
Pulegone, a monoterpenoid monocyclic, which is a small compound in cannabis. It’s present widely in rosemary. Rosemary breaks down acetylcholine in the brain, allowing nerve cells to communicate more effectively with each other.
Pulegone has sedative and fever-reducing properties. It may also reduce some of the side effects of THC such as short-term memory loss.
Pulegone has a pleasant peppermint aroma and is considered a good insecticide.
Sabinene is a bicyclic monoterpene whose aromas are reminiscent of Christmas, a mixture of pine and citrus. The latest studies suggest that sabinene is antioxidant and anti-inflammatory.
Sabinene exist in Norway spruce, black pepper or basil.
Geraniol produces an odor similar to that of roses. This makes geraniol a good choice for shower and bath products. It is also famous as a good mosquito repellent. On the medical side, geraniol is promising in the treatment of neuropathy.