21.10.2017 Feature Article

Terpenoids: What are they?

Terpenoids: What are they?
21.10.2017 LISTEN

Terpenes are fragrant oils that give cannabis its aromatic diversity. They're what give Blueberry its signature berry smell, Sour Diesel its funky fuel flavor, and Lavender its sweet floral aroma. These oils are secreted in the flower's sticky resin glands, the same ones that produce THC, CBD, and other cannabinoids. As science and technology carry us to better understandings of cannabis, we’re beginning to see that there’s a lot more to marijuana than its cannabinoid content.

The term “cannabinoid” refers to one of a number of chemical compounds found in the weed plant. If we want to get technical about things, the proper name for these plant-based molecules is “phytocannabinoid”. When you smoke or ingest marijuana, these are the chemicals that interact with cells in your body to produce medical benefits.

Cannabis at its turn contains a wide range of terpenes (over 200) that are thought to interact synergistically with the cannabinoids in the plant, and to enhance its health effects.

BCP (beta-caryophyllene) for example is a terpene found in the cannabis plant that is known to activate the CB2 receptor in the endocannabinoid system and to exert anti-inflammatory effects. It’s non-psychoactive, and is the first FDA approved dietary cannabinoid, being used as food additive.

Vitamin A is also a terpene, although we don’t generally think of it this way. Conifers produce large amounts of these compounds, and most plants produce higher quantities of terpenes in the warmer seasons.

Others also called it terpenoids. The words terpene and terpenoid are increasingly used interchangeably, although these terms do have different meanings. The main difference between terpenes and terpenoids is that terpenes are hydrocarbons (meaning the only elements present are carbon and hydrogen); whereas, terpenoids have been denatured by oxidation (drying and curing the flowers) or chemically modified.

Terpenes are synthesized in cannabis in secretory cells inside glandular trichomes, and production is increased with light exposure. These terpenes are mostly found in high concentrations in unfertilized female cannabis flowers prior to senescence (the condition or process of deterioration with age). The essential oil is extracted from the plant material by steam distillation or vaporization. Many terpenes vaporize around the same temperature as THC (which boils at about 157°C), but some terpenes are more volatile than others. Terpenes also play an incredibly important role by providing the plant with natural protection from bacteria and fungus, insects and other environmental stresses.


It is well established that cannabis is capable of affecting the mind, emotions and behavior. The main psychotropic cannabinoid, delta-9-tetrahydrocannabinol (THC) has been intensely studied. However, many of the other cannabinoids, terpenoids and flavonoids found in medical marijuana that play a big role in boosting the therapeutic effect of cannabis remain understudied.

Terpenes are common constituents of flavorings and fragrances. Terpenes, unlike cannabinoids, are responsible for the aroma of cannabis. The FDA and other agencies have generally recognized terpenes as “safe.” Terpenes act on receptors and neurotransmitters; they are prone to combine with or dissolve in lipids or fats; they act as serotonin uptake inhibitors (similar to antidepressants like Prozac); they enhance norepinephrine activity (similar to tricyclic antidepressants like Elavil); they increase dopamine activity; and they augment GABA (the “downer” neurotransmitter that counters glutamate, the “upper”). However, more specific research is needed for improved accuracy in describing and predicting how terpenes in cannabis can be used medicinally to help treat specific ailments / health conditions.

What is a Cannabinoid?
There are over 480 natural components found within the Cannabis sativa plant, of which 66 have been classified as "cannabinoids;" chemicals unique to the plant. The most well-known and researched of these, delta-9-tetrahydrocannabinol (Δ9-THC), is the substance primarily responsible for the psychoactive effects of cannabis.

The effects of THC are believed to be moderated by the influence of the other components of the plant, most particularly the cannabinoids.

The cannabinoids are separated into subclasses. These are as follows:

Cannabigerols (CBG);
Cannabichromenes (CBC);
Cannabidiols (CBD);
Tetrahydrocannabinols (THC);
Cannabinol (CBN) and cannabinodiol (CBDL);
Other cannabinoids (such as cannabicyclol (CBL), cannabielsoin (CBE), cannabitriol (CBT) and other miscellaneous types).

What Do Cannabinoids Do?
Like opiates (substances derived from the opium poppy such as heroin), cannabinoids affect the user by interacting with specific receptors, located within different parts of the central nervous system. Two kinds of cannabinoid receptors have been found to date and are termed CB1 and CB2. A substance that occurs naturally within the brain and binds to CB1 receptors was discovered in 1992 and termed "anandamide." Additional naturally occurring substances that bind to CB1 have since been discovered, and these, together with the receptors are termed the "endogenous cannabinoid system."

The actual effects that the cannabinoids have reflect the areas of the brain they interact with. Interactions tend to occur in our limbic system (the part of the brain that affects memory, cognition and psychomotor performance) and mesolimbic pathway (activity in this region is associated with feelings of reward) and are also widely distributed in areas of pain perception.

We are still learning about the endogenous cannabinoid system. Much of the research however, has focused on the many potential medical uses of man-made cannabinoids, called "synthetic analogues."

What is the Difference Between Cannabinoids?

The major differences between the cannabinoids are determined by the extent to which they are psychologically active. Three classes of cannabinoids, the CBG, CBC and CBD are not known to have such an effect. THC, CBN, CBDL and some other cannabinoids on the other hand are known to be psychologically active to varying degrees.

CBD is probably the most abundant cannabinoid, contributing up to 40% of cannabis resin. Interestingly, CBD may actually have anti-anxiety effects and lessen the psychoactive effects of THC. This means that a plant with a greater percentage of CBD may reduce the intensity of the effects of the THC, which in effect lowers the potency of the plant. Use of a cannabis plant with less CBD has been shown to have an increased psychological impact and result in unwanted effects such as anxiety.

When THC is exposed to air it oxidizes and forms CBN. CBN is only very weakly psychoactive and not unlike CBD interacts with THC to reduce its effects. This is why cannabis that has been left out unused will have increasing amounts of CBN and decreasing amounts of THC and thus lose potency.

Synergistic Effects


The Carlini et al study demonstrated that there may be potentiation (a form of synaptic plasticity that is known to be important for learning and memory) of the effects of THC by other substances present in cannabis. The double-blind study found that cannabis with equal or higher levels of CBD and CBN to THC induced effects two to four times greater than expected from THC content alone. The effects of smoking twice as much of a THC-only strain were no different than that of the placebo.

This suggestion was reinforced by a study done by Wilkinson et al to determine whether there is any advantage in using cannabis extracts compared with using isolated THC. A standardized cannabis extract of THC, CBD and CBN (SCE), another with pure THC, and also one with a THC-free extract (CBD) were tested on a mouse model of multiple sclerosis (MS) and a rat brain slice model of epilepsy.

Scientists found that SCE inhibited spasticity in the MS model to a comparable level of THC alone, and caused a more rapid onset of muscle relaxation and a reduction in the time to maximum effect than the THC alone. The CBD caused no inhibition of spasticity. However, in the epilepsy model, SCE was a much more potent and again more rapidly-acting anticonvulsant than isolated THC; however, in this model, the CBD also exhibited anticonvulsant activity. CBD did not inhibit seizures, nor did it modulate the activity of THC in this model. Therefore, as far as some actions of cannabis were concerned (e.g. anti-spasticity), THC was the active constituent, which might be modified by the presence of other components. However, for other effects (e.g. anticonvulsant properties) THC, although active, might not be necessary for the observed effect. Above all, these results demonstrated that not all of the therapeutic actions of cannabis herb is due to the THC content.


Dr. Ethan Russo further supports this theory with scientific evidence by demonstrating that non-cannabinoid plant components such as terpenes serve as inhibitors to THC’s intoxicating effects, thereby increasing THC’s therapeutic index. This “phytocannabinoid-terpenoid synergy,” as Russo calls it, increases the potential of cannabis-based medicinal extracts to treat pain, inflammation, fungal and bacterial infections, depression, anxiety, addiction, epilepsy and even cancer.

Traditional medical practitioners have known for millennia that plants have the power to prevent, treat or otherwise improve a number of medical conditions. Plants contain bioactive phytochemicals, such as tocopherols, polyphenols and ascorbic acid, which perform important functions in both plants and humans.

Terpenoids (aka isoprenoids) are another beneficial phytochemical — one that many people haven’t heard of before. Out of the seemingly countless compounds in plants, terpenoids represent the largest and most diverse class of beneficial chemicals. More than 40,000 individual terpenoids exist, and new ones are discovered every year says Dr.Mercola.

Plants use terpenoid metabolites to support basic functions like growth, repair and development. However, according to research published in Advances in Biochemical Engineering and Biotechnology, they “use the majority of terpenoids for more specialized chemical interactions and protection.”


Among humans, terpenoids have long been valued for medicinal purposes in traditional Indian and Chinese medicines, and they’ve also been used for food, pharmaceutical and chemical purposes. The cancer drug Taxol and the antimalarial drug artemisinin are both terpenoid-based drugs, but the plant compounds are perhaps most well-known for being the main constituents of the essential oils in many plants.

Because they’re responsible for the wide variety of plant flavors and aromas — from flowery and fruity notes to woody undertones — they’re a sought-after commodity by the flavor and fragrance industries. Further, as noted by a study in the journal Recent Patents on Food, Nutrition & Agriculture:

“Terpenoids represent the oldest known biomolecules, having been recovered from sediments as old as 2.5 billion years. Among plant secondary metabolites, they are the most abundant and diverse class of natural compounds. The diversity of terpenoids is probably a reflection of their many biological activities in nature, which has made them a widely used resource for traditional and modern human exploitation.”

Eating Terpenoids Daily May Benefit Metabolic Disorders, Including Diabetes


As they pertain to your health, there’s evidence that these powerful plant compounds play a beneficial role in metabolism. According to researchers at Kyoto University in Japan, terpenoids can modulate the activities of ligand-dependent transcription factors, particularly peroxisome proliferator activated receptors (PPARs). PPARs help regulate genes involved in the metabolism of fat and glucose, and PPAR activation has a beneficial effect on blood pressure, cholesterol levels, diabetes, heart disease and stroke.

“Because PPARs are dietary lipid sensors that control energy homeostasis, daily eating of these terpenoids might be useful for the management for obesity-induced metabolic disorders, such as Type 2 diabetes, hyperlipidemia, insulin resistance and cardiovascular diseases,” the researchers wrote, adding:

“Dietary patterns rich in vegetables and fruit are associated with a lower prevalence of metabolic syndrome. Because most of the terpenoids are of plant origin and they are contained in vegetables and fruit, dietary terpenoids may contribute to a decrease in risk of metabolic syndrome. Moreover, because the terpenoids constitute one of the largest families of natural products, more potent and useful PPAR activators may exist.”

Terpenoids May Be Valuable as Cancer-Fighting Antioxidants and More

Terpenoids are classified into several classes of chemicals including monoterpenes, diterpenes, triterpenes and tetraterpenes, the latter of which contain the more familiar carotenoids, including lutein and lycopene. Many of them are known for their antioxidant properties as well as their potential for fighting cancer. Lycopene, for instance, may play a role in breast and prostate cancer prevention.

A review published in the journal Vitamins and Hormones also noted, “The monoterpenes limonene and perillyl alcohol may be promising substances in cancer therapy,” noting that combinations of antioxidants, in particular, may exert synergistic effects.


Terpenoids have also been singled out as having potential to prevent and treat liver cancer. According to a study in the World Journal of Hepatology, “A large number of terpenoids exhibit cytotoxicity against a variety of tumor cells and cancer preventive as well as anticancer efficacy in preclinical animal models.”

Ten new terpenoids, along with 15 known terpenoids, were even shown to reverse multidrug resistance in a multidrug-resistant tumor cell line. And nimbolide — a bioactive terpenoid compound found in neem — may shrink prostate tumors by as much as 70 percent while suppressing metastasis by about 50 percent when taken orally for three months. The plant compounds have also shown potential as anti-colon cancer agents, with researchers explaining:

“Anticancer properties of terpenoids are associated with various mechanisms like counteraction of oxidative stress, potentiating endogenous antioxidants, improving detoxification potential, disrupting cell survival pathways and inducing apoptosis.”

In addition, structurally some terpenoids are similar to human hormones, and a diet rich in terpenoids is inversely related with the risk of chronic diseases like cancer, according to research published in Current Drug Targets — including hormone-related cancers like breast and prostate cancers. “[Pr]e-clinical studies support clinical application of … naturally occurring terpenoids in treatment of hormone-related human cancers,” the researchers noted.

Terpenoids Are Anti-Inflammatory, Pain-Relieving and More

Beyond their cancer preventive effects, terpenoids also have the following beneficial properties:

Analgesic (pain relieving)
They may also help explain why essential oil therapy can be so effective, as terpenoids are known to affect animal and human behavior when inhaled from ambient air. As terpenoids are also found in cannabis, it’s been suggested that terpenoids may work synergistically with cannabinoids to produce some of the beneficial effects of medical marijuana. According to a study in the British Journal of Pharmacology:

“[Terpenoids] display unique therapeutic effects that may contribute meaningfully to the entourage effects of cannabis-based medicinal extracts … phytocannabinoid-terpenoid interactions … could produce synergy with respect to treatment of pain, inflammation, depression, anxiety, addiction, epilepsy, cancer, fungal and bacterial infections (including methicillin-resistant Staphylococcus aureus).”


Scientifically Speaking, What Are Terpenoids?

Natural Products Chemistry & Research describes terpenoids as “a large and diverse class of naturally-occurring organic compounds similar to terpenes,” and “any group of hydrocarbons that contain terpenes, derived from five-carbon isoprene units.” They can form cyclic structures such as sterols. Further:

“Most are multicyclic structures that differ from one another not only in functional groups but also in their basic carbon skeletons. These lipids can be found in all classes of living things, and are the largest group of natural products …”

Most have a fragrance but no color, are lighter than water and volatile with steam (aka “at steam”), at which point it volatilizes, or changes into a gas. A few terpenoids are solids, such as camphor, but all are soluble in organic solvent and usually insoluble in water. Most of them are optically active and many are open-chain or connected, cyclic unsaturated compounds (that form a ring) with one or more double bonds.

Terpenes and hemp oil
Unlike marijuana, hemp does not have a strong flavor and is not referred to as an aromatic plant, therefore the terpene profile of hemp is a bit less significant than that of marijuana. But the plant still contains such compounds, and none of them are psychoactive. Terpenes in hemp have anti-inflammatory, anti-bacterial and anti-viral properties, the most known of them being caryphyllene and myrcene.

The hemp plant contains 120 terpenes, but depending on the processing method, these can or cannot be found in the CBD oil. Oil made of hemp seeds is less abundant in terpenes than the similar product obtained from other portions of the plant (Hendriks et al, 1978).

Hemp contains mostly monoterpenes and sesquiterpenes (Turner et al, 1980), which can be concentrated into essential oils through steam distillation methods. Cannabinoids have no smell, so the flavor and aroma of hemp products depends on their terpenes profile.

Plants Containing the Most Terpenoids
Terpenoids are found in many living organisms throughout nature, especially plants, fungi and marine animals. If you want to increase your intake of these beneficial compounds via your diet, eating more whole plant foods is an excellent way to start. By eating a wide variety, you can be sure you’re consuming a variety of different terpenoids. For example, a list of dietary terpenoids being evaluated for anticancer activity, and their dietary sources, was published in the journal Frontiers in Bioscience:

Monoterpenes: Lemons, oranges, grapefruit, caraway, bergamot, peppermint, spearmint, dill, tomatoes

Diterpenes: Carrots, spinach, pumpkin, broccoli, mango, papaya, cherries, tomatoes, oranges, cabbage, watermelon, lettuce

Triterpenoids: Olives, mangos, strawberries, grapes, figs

Terpenoid chromanols: Almonds, walnuts
Carotenoids: Tomatoes, oranges, carrots, peas, sprouts, greens

In addition, thyme and coriander seed oil, which contains up to 70 percent linalool (a terpenoid), are also good sources, as are mushrooms and chamomile. Black seed oil, which is rich in the terpenoid thymoquinone, is another excellent option. Thymoquinone is known to have anticancer effects. Research published in Drug Discovery Today concluded thymoquinone has a long history of battling cancer in vitro and in vivo (in "test tube" experiments and animal studies), and modulates 9 of the 10 hallmarks of cancer.

Thymoquinone extract from black cumin appears to be effective against cancers in the blood, lung, kidney, liver, prostate, breast, cervix, colon and skin. Black cumin oil is popular in the health food scene, but for optimum nutrition it may be better to use the seeds because essential fatty acids are easily destroyed by heat or prolonged exposure to air. One problem with extracting oil from seeds is that processing is required, so damage is done.

I soak the seeds overnight, then put them in a smoothie. They're a little on the bitter side, so putting sweetener in it such as monk fruit or stevia gives it a tasty boost. Research is ongoing looking into the effects of various terpenoid extracts, such as that from the Siberian fir, a coniferous evergreen tree, which has shown potential anti-aging and anti-cancer effects says mercola

The bottom line is that terpenoids appear to be phenomenal for your health, and if you’d like to consume more of them, the easiest way to do so is to eat more vegetables, herbs and fruits. Beyond that, many plant extracts, essential oils and medicinal plants also contain high concentrations, and working with a holistic health care practitioner who is familiar with some of the different varieties, and their individualized uses, may help you to determine the best sources for you.

Dr. Raphael Nyarkotey Obu is a research Professor of Prostate Cancer and Holistic Medicine at Da Vinci College of Holistic Medicine, Larnaca city, Cyprus and President of Men's Health Foundation Ghana. You can reach him on 0541234556