September 25, 2019

What Are Terpenes?

The cannabis plant has a variety of recreational and medicinal benefits, making it the subject of intensive research and the center of an ever-expanding industry. In other words, cannabis is hot right now! That means everyone is examining it much more closely to understand precisely how this amazing plant breaks down. For example, identifying all the various compounds present in cannabis distillate, for example terpenes, allows researchers to understand exactly how the final product will affect the users. It also means that cannabis distillate manufacturers can target specific compounds in order to increase or decrease certain effects.

Over the years, researchers have tried to pinpoint precisely how many natural compounds are present in the plant. A landmark study in 1980 identified 423; interestingly enough, this is where many people mistakenly believe the term 420 comes from when referencing cannabis and its consumption. Another influential study in 1995 identified 483, thereby adding 60 compounds to the total number known.

Researchers continued to find more and more constituents, and as of 2014 there are now over 545 that have been identified. Although these various compounds can be categorized into a variety of different types, let’s examine the three fundamental components:

  1. Cannabinoids – Everyone knows about these! As you can see, they are so instrumental in the chemical makeup of the cannabis plant that they were actually named after it. Current research has concluded that approximately 104 of the total compounds are cannabinoids. The two most widely known cannabinoids are tetrahydrocannabinol (THC) and cannabidiol (CBD), and most of the known psychoactive and physiological effects of cannabis distillate are attributed to these compounds.
  2. Terpenes – These are aromatic hydrocarbons that are found in significant quantities in cannabis as well as a wide variety of other plants. In fact, essential oils (EOs) that are extracted from plants are largely made up of terpenes, thus giving them their signature scents. With over 140 different terpenes found in cannabis, these compounds play a crucial role in the variety and diversity of different strains. It’s also important to note that most terpenes vaporize at about the same temperature as THC (157 degrees C or 315 degrees F).
  3. Flavonoids – Also known as bioflavonoids, this is a diverse group of phytonutrients (a fancy word for “plant chemicals”) found in nearly all fruits and vegetables. These are the compounds responsible for the vivid colors you find in plants, with approximately 20 different types of flavonoid present in various cannabis strains. In fact, of all the chemical constituents identified in cannabis, approximately 10% of these are flavonoids. Much like cannabinoids and terpenes, these are also found in cannabis distillate as well.

So these are the basic building blocks of the cannabis plant. It should be noted that it is the interplay between these various chemical constituents that gives cannabis its telltale effects, although this article will be focusing exclusively on terpenes. This is also true for cannabis products that focus on one specific cannabinoid, including THC distillate.

Furthermore, terpenes are responsible for that unique and distinct aroma of cannabis that we’re all familiar with. They’re not called aromatic hydrocarbons for nothing! Remember, they’re also the primary components in essential oils (EOs), which are extracted from plants via steam distillation or vaporization.

Where Are Terpenes Produced Within the Cannabis Plant?

Well, that’s a good question. They are synthesized inside glandular trichomes and then secreted by specialized cells. Their production is increased over time and is triggered by exposure to light, especially light in the ultraviolet spectrum (otherwise known as UV rays). The highest concentrations of terpenes are found in unfertilized female flowers of the cannabis plant until the onset of senescence (which is just a fancy way of saying “old age” in plants).

Furthermore, if the extraction process is done properly, then these terpenes will be preserved in the final cannabis or THC distillate. This is a good thing, as these terpenes have a wide variety of benefits, both in addition to and independently of the underlying cannabinoids.

Terpenes vs. Terpenoids – What’s the Difference?

In a lot of the cannabis literature, the terms terpene and terpenoid are used interchangeably. Strictly speaking, this is not entirely accurate. So let’s take a moment to look at the functional differences:

  1. Terpenes – As mentioned above, these are hydrocarbons. So what exactly does this mean? Well, in chemistry, a hydrocarbon is any compound that is only made up of carbon and hydrogen. These are usually long chains of these elements that have a specific three-dimensional shape that affect their function.
  2. Terpenoids – These are terpenes that have undergone denaturation. This is just a fancy way of saying that they have lost their three-dimensional shape and are now just a string of carbon and hydrogen atoms, held together by chemical bonds. This is usually caused by oxidation, which is a chemical process by which atoms lose their electrons. In terms of cannabis, this is usually caused by drying or curing the flowers.

This all may seem a bit complex, but just imagine a terpene like a bundle of yarn (where the string itself is a sequence of carbon and hydrogen atoms). If you take that bundle of yarn and pull it apart, thereby straightening it, then that is basically like the process of denaturation. It’s almost as if you are flattening the biomolecular structure, thereby greatly affecting its function.

All Together Now – The Entourage Effect in Cannabis Distillate

Let’s take a moment to discuss the entourage effect. This is a type of synergy, by which the various compounds contained within cannabis or THC distillate complement each other and work better in tandem than in isolation. This is also known as potentiation and just means that the psychoactive and medicinal qualities of the cannabinoids are strongest when combined with terpenes (and flavonoids, though that’s a subject for another article).

In fact, renowned organic chemist and cannabis researcher Raphael Mechoulam stated in an influential 1999 paper that, “[The entourage effect] may play a role in the widely held view that in some cases plants are better drugs than the natural products isolated from them.” For example, this groundbreaking 1974 study found that full-spectrum cannabis extracts (with all compounds present) had effects that were two to four times greater than THC distillate alone.

Just A Quick Note – How Do Terpenes Interact with the Brain?

Before we go on a deep dive of the most common terpenes found in cannabis, let’s quickly note that these aromatic compounds also act directly on the central nervous system (CNS) by interacting with receptors and neurotransmitters in the following ways:

  1. As serotonin uptake inhibitors, similar to antidepressants like Prozac. The neurotransmitter serotonin is responsible for a variety of physiological processes as well as learning, reward, cognition, memory, and mood.
  2. They enhance the activity of norepinephrine, similar to tricyclic antidepressants like Elavil. This neurotransmitter and hormone mobilizes the body and brain, particularly in dangerous or stressful situations (the fight or flight response). In other words, norepinephrine increases alertness or arousal, focuses attention, and is crucial in the formation and retrieval of memories.
  3. They increase dopamine activity; this is a big part of why cannabis makes the user feel so euphoric. In popular culture and media, dopamine is frequently reduced to being a “pleasure chemical”, but it would be more accurate to describe it as the main neurotransmitter responsible for motivation and reward.
  4. They augment GABA neurotransmitters, much like the class of anti-anxiety medications known as benzodiazepines. GABA is the primary inhibitory neurotransmitter, meaning that it acts like a downer (as opposed to glutamate, which is more of an upper).

Remember, terpenes reach full efficacy and function when combined with the other cannabis compounds due to the entourage effect.

Breaking It Down – What Are The Various Terpenes In Cannabis Distillates?

So let’s get down to brass tacks and break terpenes down on a more detailed level. The cannabis plant is remarkably versatile in its chemical composition; in fact, it’s best to think of each strain as a unique combination of its constituent cannabinoids, terpenes, and flavonoids. It’s almost like a chemical fingerprint, with no two strains being totally identical.

The chemical complexity of this plant is truly remarkable, but that makes total sense considering the long history and lineage of cannabis cultivation. Remember, people have selected for certain characteristics when they cross-breed or hybridize different strains, resulting in a rich tapestry of chemical constituents.

Remember that there are 140 different terpenes present in unprocessed cannabis; we can’t go over all of these, so let’s just examine the most common and widely researched:

Myrcene

This is the most abundant terpene in cannabis. In fact, research has indicated that myrcene makes up nearly 65% of the total terpene profile in certain cannabis strains. Remember that terpenes are highly aromatic compounds, and myrcene is no exception: it has a musky, earthy smell reminiscent of cloves. Cannabis strains that have at least 0.5% of myrcene are almost always indica – consequently, myrcene is known for its strong sedating effects.

Studies have also shown that it is useful for treating chronic pain and inflammation throughout the body. As a result, myrcene-heavy indica strains are usually used during radiation or chemo-therapy. Interestingly enough, mango also contains a high concentration of myrcene, so eating one about 45 minutes before cannabis consumption will potentiate the effects of the indica.

Additionally, this 2002 study concluded that myrcene has sedative effects on rodents, including:

  1. Suppressing locomotor activity
  2. Inducing sleep
  3. Reducing motor coordination

This makes total sense, as pretty much all of these effects are present in indica strains that are consumed by humans. Furthermore, do you remember those GABA receptors we discussed earlier? Well, this 2014 study concluded that much of myrcene’s sedating qualities was due to its ability to potentiate GABA receptors.

Finally, this 2000 study also showed that myrcene had anticonvulsant effects and suppressed seizure activity.

Limonene

This is the second most abundant terpene in cannabis, although not every strain will have any present. Furthermore, if you look closely at the name, you can probably see why it has a citrus-like aroma that is similar to lemons. This makes perfect sense as all citrus fruits contain high concentrations of limonene. As a result, it is frequently found in cleaning products and cosmetics.

Additionally, limonene reduces stress and boosts mood as well as having antibacterial and antifungal properties. Certain studies have even found that it is useful in reducing tumor size, especially in breast cancer. If you’re looking for a cannabis strain with lots of limonene, then look for the words sour or lemon in the name!

Linalool

It’s likely that you know the telltale smell of cannabis; it’s an unmistakable scent that is really unique. Well, myrcene and linalool are the two terpenes that give cannabis its signature spicy, pungent, and floral aroma. In fact, the majority of cannabis strains have significant amounts of this particular terpene as well as cinnamon, coriander, lavender, and mint plants. Much like the essential oils extracted from those plants, cannabis that is high in linalool produces relaxation and sedation. Additionally, this terpene has brought relief to patients suffering from arthritis, insomnia, depression, cancer, and seizures.

Pinene

This terpene comes in two forms: alpha-Pinene and beta-Pinene, both of which are especially abundant in various species of pine trees. It can also be found in basil, orange peels, parsley, and rosemary. Studies have indicated that the anti-inflammatory effects of pinene make it useful in helping to treat arthritis and Crohn’s disease. It may also reduce tumor size in patients suffering from cancer and limit the amnestic effects of excessive THC consumption. Furthermore, this 2016 study also indicates that it has the same GABA activity as myrcene, thereby making it an effective sedative and anxiolytic.

Alpha-bisabolol

With a pleasant and flowery aroma, this terpene is found in the chamomile flower and candeia tree. Alternately known as bisabolol or levomenol, it has traditionally been used cosmetics. However, the recent explosion of research into cannabis and its constituent compounds has indicated that it likely has a wide variety of medicinal benefits, including as a:

  1. Antibacterial (making it a great antiseptic for wounds or cuts)
  2. Antioxidant
  3. Anti-inflammatory
  4. Analgesic

Eucalyptol

If you look closely at the name, it’s easy to see why this is the primary terpene found in the eucalyptus tree. It’s also known as cineole and has a minty aroma, although it makes up only about 0.06% of the terpene profile in cannabis. Again, like many of the other terpenes discussed, it has been used in cosmetics for quite some time. Despite its relatively low concentration, however, it does exhibit extensive medicinal benefits, including as an:

  1. Antibacterial
  2. Antifungal
  3. Analgesic

Additionally, according to this 2003 study and this 2005 study, it has been used to treat bronchitis, sinusitis, chronic rhinitis as well as asthma due to its anti-inflammatory effects.

Caryophyllene

Seeing as how this terpene is found basil, black pepper, cinnamon, cloves, oregano, and rosemary, it has a signature peppery and spicy smell. It is the only terpene that binds directly with cannabinoid receptors; in fact, its high reactivity with CB2 receptors in the ECS make it an exceptionally effective as an analgesic, anxiolytic, and anti-inflammatory agent. Based on a 2014 study performed on mice, it may reduce cravings for alcohol for patients suffering from a substance abuse disorder and the researchers even indicated that it could be used to reduce alcohol withdrawal symptoms.

Humulene

This compound is one of the primary terpenes found in hops, cloves, sage, and black pepper, giving it an earthy, spicy, and woody aroma. Like most of the other terpenes discussed, it is a powerful anti-inflammatory, antimicrobial, and analgesic. However, it is unique in that it is an appetite suppressant, making it a potentially powerful tool for weight loss and treating medical obesity.

Nerolidol

Also known as peruviol and penetrol, nerolidol is found in citronella, ginger, and niaouli. Its wooden, earthy, and bark-like aroma makes it a popular ingredient in perfumes. It is also known for its antimicrobial properties and its ability to inhibit the growth of certain parasites (most notably Leishmaniasis). Additionally, this 2007 study found that it can reduce lesions in certain fungal infections and this 2003 study concluded that it potentiates the effects of antibiotics. Remember, terpenes are known for their entourage effect, and it appears as if this goes beyond just cannabis consumption. In other words, they’re good for you in a variety of ways!

It has two isomer forms: cis- and trans-nerolidol, with the latter being more common. It is found in jasmine, tea tree oil, and lemongrass and it has an aroma that is a combination of citrus and wood with notes of apple, lemon, and rose. It also has antifungal, antioxidant, antiparasitic, anticancer, and antimicrobial properties.

Ocimene

This compound is responsible for the sweet, citrusy, woody, and herbaceous aromatic tones of certain cannabis strains and its distinctly pleasant smell makes it a popular ingredient in the perfume industry. This is a specific type of terpene known as a monoterpene and is found in:

  1. Hops
  2. Kumquats
  3. Mangoes
  4. Tomato plants
  5. Bergamot
  6. Citrus unshiu (also known as satsuma mandarin)
  7. Lavender
  8. Basil
  9. Orchids
  10. Pepper

Interestingly enough, ocimene appears to be a crucial part of these plants’ defense mechanisms against harmful pests, especially aphids.

But let’s not forget that ocimene, like all the other terpenes, has its fair share of medicinal properties too. This 2014 study concluded that it was an immensely effective anti-inflammatory and this 2013 study concluded that it was not only a potent antioxidant, but that it also inhibited crucial enzymes connected to the development of hypertension and type 2 diabetes.

Terpinolene

This is an interesting terpene because it is found in a wide number of strains, but usually in lower amounts. It is sometimes jokingly referred to as the least-common common terpene. Its aroma is defined by its herbal, floral, and piney notes and it is also found in nutmeg, tea tree, various conifer species, apples, lilacs, and cumin.

According to this 2014 study (which also analyzed linalool, eucalyptol, and pinene), terpinolene has potent antibacterial and antioxidant properties. Additionally, strains that are rich in terpinolene have highly sedating qualities – this 2013 study indicates that it acted as a strong sedative when administered to laboratory mice. Also, this 2005 study concluded that terpinolene can reduce the risk of heart disease by preventing oxidation in low-density lipoproteins (LDLs) and this 2012 study indicated that it inhibits the growth of cancer cells by downregulating Protein kinase B (also known as Akt).

Terpineol

This terpene is superficially very similar to terpinolene, although it is not quite so omnipresent in various strains. Its strong floral scent is frequently compared to apple blossoms or lilacs with a smidge of citrusy lemon while it tastes kind of like minty anise. This pleasant combination of smell and taste makes it a common ingredient in cosmetics, perfumes, and sweet foods.

This is one of the more heavily sedating terpenes and is most often found in indica strains. Much like myrcene and pinene, terpineol also increases GABA activity in cells and even exhibits the qualities of an anesthetic. It is also a potent antioxidant and antimicrobial.

Delta-3 Carene

This terpene has a sweet, cypress-like smell and is found in basil, bell peppers, cedar, pine, and rosemary. It is unique amongst terpenes, however, in that it stimulates the growth and repair of bone tissue, potentially acting as a treatment for patients suffering from arthritis, fibromyalgia, and osteoporosis.

Camphene

The smell of camphene can be best described by the word loamy or in general terms as damp woodlands, fir needles, and earth. In terms of other terpenes, it is most frequently confused with myrcene.

When it is combined with ascorbic acid (widely known as vitamin C), it becomes a potent antioxidant and is frequently used in topical medicines to treat eczema and psoriasis. It is also unique in that it can help treat cardiovascular disease by lowering the levels of triglycerides and bad cholesterol.

Borneol

Borneol can be found in camphor, mint, and rosemary, thereby giving it a minty, herbal aroma. This fascinating terpene is a naturally effective insect repellent, meaning that it can be effective at preventing the spread of blood-borne diseases like West Nile virus that are carried by mosquitoes, fleas, or ticks. Also, this 2014 study indicated that this terpene, in a form known as bornyl caffeate, inhibits breast cancer cells via a cellular process known as apoptosis.

Valencene

This terpene is can be found in high concentrations in sweet Valencia oranges – hence the name, naturally. Much like borneol, it is a natural insect repellent, although its smell is more accurately described as a sweet citrus scent. Little is known about this compound, although it is likely that it has various medicinal benefits just like the other terpenes found in cannabis.

Geraniol

Much like the other terpenes we’ve discussed, look closely at the name geraniol to deduce a defining factor about this compound: it is most frequently found in geraniums! Additionally, it can be found in tobacco or lemon plants and it has a scent that is a mix of peaches, plums, and rose grass. Due to its highly pleasing aroma, it is frequently used in cosmetics, body lotions, and bath products. Much like valencene, it can repel insects like mosquitoes.

It is still the subject of extensive research, but so far studies have indicated that its medicinal benefits include:

  1. Antioxidant
  2. Anti-cancer
  3. Antimicrobial (bacteria, fungus, and viruses)
  4. Anti-spasmodic
  5. Neuroprotectant

The 3 Simple Reasons Why Terpenes Matter

So, in conclusion, let’s quickly break down why terpenes matter:

  1. They directly contribute to the efficacy of cannabis distillate via the entourage effect.
  2. In addition their synergy with cannabinoids, they also have medicinal benefits, ranging from antidepressant-like qualities to sedation and antimicrobial properties.
  3. They give cannabis products their distinct smell and flavor.

It’s also important to note that there is a growing body of research supporting the notion that various terpenes may be valuable in treating neurodegenerative brain diseases like Alzheimer’s. For example, see this 2012 study, this 2017 study, and this 2018 study.

So that, in a nutshell, is why terpenes are so important. They greatly enhance the effects of cannabis and THC distillate, both medicinally and recreationally. Remember, they do so both in isolation and as “part of the team”; all of these various compounds are working together, making cannabis an invaluable addition to our lives.

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