A Brief Introduction To Terpenes: Monoterpenes, Sesquiterpenes, And Terpenoids

The cannabis plant is chock full of various compounds that preliminary research suggests may have myriad therapeutic applications. Cannabinoids, like THC and CBD, are the most studied and perhaps most essential of these kinds of compounds. However, the industry has recently shifted some of its focus away from cannabinoids and onto another class of molecule abundantly found in the cannabis plant—terpenes.

These days, cultivation and marketing aren’t just about hitting high percentages of CBD and THC. Consumers are interested in a more holistic cannabis experience, placing increased value on the aromas and flavors of a particular strain, and the interplay of both the cannabinoid and terpene profile. In response, modern cultivators often include a terpene chart denoting the complete terpene profile on their product packaging. But what exactly are terpenes, and what do they have to do with cannabis?

What Are Terpenes?

Let’s start with the terpenes definition. Terpenes are aromatic molecules found in all kinds of vegetation, which give individual plants and flowers their unique scents. Originally, plants developed terpenes for evolutionary purposes. Sweet-smelling saccharine terpenes like linalool help attract pollinators, while bitter terpenes like humulene help ward off herbivorous predators.

As anyone who’s ever smelled cannabis can tell you, the plant itself has a complex fragrance. With pungent petrol and skunky aromas that are often complemented by notes of sweet fruit and musky, earthy undertones, the nuanced aroma of cannabis can sometimes be difficult to describe. That’s because the cannabis plant, in particular, produces a wide array of various terpenes.

What Are Monoterpenes

Terpenes can be classified differently depending on their chemical structure. Monoterpenes are the simplest kind of terpenes. Their chemical structure consists of 10 carbon atoms and 2 isoprene units. Common monoterpenes and their derivatives include:

• Myrcene
• Limonene
• Linalool
• Pinene  

Monoterpenes are some of the more volatile terpenes, which are more easily converted to vapor. Because of this, monoterpenes tend to contribute more to the aromatic properties of a given cannabis strain.

What Are Sesquiterpenes?

The Latin prefix sesqui translates to “one and a half,” so you might be able to put together that a sesquiterpene is made up of 15 carbon atoms and 3 isoprene units. Common sesquiterpenes and their derivatives include:

• Caryophyllene
• Humulene
• Longifolene
• Germacrene

With their extra isoprene unit, Sesquiterpenes are bulkier than monoterpenes and tend to be less fragile, holding up more reliably during the cannabis drying and curing process.

What Are Terpenoids?

The terms terpene and terpenoid are often used interchangeably in the cannabis industry, but each word actually has a distinct meaning.

Terpenoids are terpenes that have undergone oxidation, resulting in the addition of oxygen to the typical terpene chemical structure composed solely of carbon and hydrogen. Terpenoids have a much lower vapor pressure than terpenes, making them an overall less volatile compound.

Do Terpenes Get You High?

When discussing any cannabis compound, inevitably, the question of the given compound’s psychoactive qualities will arise. In the case of terpenes, no, they don’t get users high per se, but that doesn’t mean all they do is smell nice.

Burgeoning research into the efficacy of terpenes as therapeutic agents suggests that these fragrant compounds could have legitimate medicinal applications. Additionally, the entourage effect theory posits that cannabis terpenes could work in tandem with cannabinoids to enhance each compound’s individual benefit.

What Role Do Terpenes Play In Cannabis?

While there’s still some debate in the scientific community as to just how beneficial cannabis terpenes are, preliminary research strongly suggests that cannabis terpenes may have potential health benefits.

For example, various terpenes have antimicrobial properties which could help protect the body against pathogenic bacteria.

Research also suggests that some terpenes could have anti-stress and antidepressant qualities. A 2014 clinical trial using rodent models found that the sesquiterpene caryophyllene reduced symptoms of depression in mice, and, believe it or not, 25% of current antidepressant drugs are formulated using terpene-rich herbal extracts.

Additionally, scientists have found evidence that terpenes possess cancer-fighting properties. According to one 2018 paper, “limonene, and other dietary monoterpenes have demonstrated some degree of chemotherapeutic activity against lung, pancreatic, mammary, liver, colon, and prostatic tumor models.”

Terpenes And The Entourage Effect

While terpenes have the therapeutic potential all on their own, current cannabis research indicates that they may be even more effective when combined with cannabinoids. The entourage effect theory suggests that using both cannabinoids and terpenes enhances each compound’s individual benefit. Often, the entourage effect is used to describe the ways in which CBD could potentially mitigate unwanted side effects of THC. However, this theory also applies to the relationship between terpenes and cannabinoids.

A study from this year found that the terpenes humulene, linalool, geraniol, and pinene may increase the analgesic and pain-relieving effects provided by cannabis. Another 2018 study determined that patients with epilepsy using CBD as a seizure preventative had better success and fewer side effects using full-spectrum products compared to CBD isolate.

Perhaps the most comprehensive study investigating the entourage effect is Dr. Ethan Russo’s 2011 Study, Taming THC: Potential Cannabis Synergy and Phytocannabinoid-terpenoid Entourage Effects. In it, Russo determines, “selective breeding of cannabis chemotypes rich in ameliorative phytocannabinoid and terpenoid content offer complementary pharmacological activities that may strengthen and broaden clinical applications and improve the therapeutic index of cannabis extracts containing THC, or other base phytocannabinoids.”

Terpene research is still in its relative infancy. Only time will tell what other secrets scientists will unlock about this fascinating class of compounds.

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