Terpenoids or terpenes are aromatic compounds that are found in many plants. Terpenes are key to the flavour and smell of plants, however, they are commonly associated with cannabis, as cannabis plants contain high concentrations of terpenes.

What are terpenes?

Terpenes are high aromatic compounds that determine the flavour and smells of many herbs and plants such as lavender and rosemary. Terpenes also play a vital role in plants. In some plants, the terpenes ward off pathogens, predators, and even competitors of the organism they thrive in.

There is a wide range of terpenes in nature, but only a tiny percentage of them have been investigated.

As of today, cannabis terpenes are one of the most researched topics medically. It is no surprise that cannabis terpenes are included among the most medically sourced flora like tea, thyme, Spanish sage, and citrus fruits [2].

How do terpenes work?

Most terpenes are bioactive. This means they are capable of demonstrating favourable properties such as antioxidant effect, induction or inhibition of enzymes, inhibition of receptor activities, and inhibition and induction of gene expression. Terpenes are also capable of modulating metabolic processes. The International Journal of Neuroscience suggests that terpenes’ effect can be described in two ways: psychological or pharmacological [3].

Psychological effect:

The psychological effect of terpenes is regarded as a person’s perceptions, emotions and so on. Terpenes are primarily fragrant oils, which naturally appeal to our sense of smell. A certain scent may have a domino effect on moods, emotions and so on.

Pharmacological effect:

The pharmacological effect of terpenes translates to the physical aspect of the human body. E.g. Terpenes can interact with the endocrine system (produces hormones) and with the nervous system.

Do terpenes affect people?

A lot of terpenes are bioactive, which means that they could potentially affect the body. The effect will vary based on how the person uses it and the concentration of the terpene itself.

Because terpenes produce vibrant smells, they are an integral part of many alternative therapies and form the basis of many essential oils. Inhaling the scents from certain essential oils and plants may affect a person’s stress levels and mood.

There is a plethora of medical research on isolated terpenes themselves, and some may even make their way into medical use. One study found that terpenes have demonstrated beneficial effects on the body and could even serve as a potential alternative therapy for some.[i]

Types of terpenes and their benefits

The effect and medicinal benefits of terpenes vary depending on the type of terpenes used, concentration, and manner of administration.

Below are some of the most common terpenes found in different types of plants:

Limonene

Limonene is a common terpene that is easily recognised by its scent. Limonene is the citrusy smell found in the rinds of oranges and lemons.

A study found that limonene contains the following therapeutic properties:

  • antioxidant
  • antiviral
  • antidiabetic
  • anti-inflammatory
  • anticancer

Limonene modulates the way certain immune cells behave, which may protect the body from certain disorders.

Linalool

Linalool is most rich in the lavender plant and gives the flower its powerful scent.

A study found that linalool could potentially affect the body in a variety of ways due to a range of properties, including:

  • neuroprotective
  • antidepressant
  • anticancer
  • anti-anxiety
  • anti-inflammatory
  • antimicrobial

Linalool appears to act on the body, however, more research is required to understand its effects and how it can be used for a person’s health.

Humulene

Humulene is a key component of the hop plant. Other plants, such as ginger and clove, also contain it.

A study noted that terpenes, including humulene, may have potential in the prevention of asthma and allergic reaction. In animal models, humulene reduced allergic inflammation in airways. Humulene may potentially be a helpful compound for a natural asthma treatment in the future.

Myrcene

Myrcene is commonly found in plants such as mangos, lemongrass, thyme, cannabis flowers and hops.

Myrcene is a powerful antioxidant. A study conducted on mice concluded that myrcene could help protect the brain from oxidative damage following a stroke, however, more research is required.

It is also important to bear in mind that these studies used very high concentrations of myrcene, up to 200 milligrams (mg) per kilogram (kg) (mg/kg) of weight.

Another study discovered that in a cell model of osteoarthritis noted that myrcene appeared to have an anti-inflammatory effect and could potentially prevent the breakdown of some cartilage cells.

Beta-caryophyllene

Beta-caryophyllene exists in many vegetables and herbs, such as black pepper and cloves.

Similarly, to other terpenes, beta-caryophyllene may have an anti-inflammatory effect on the body that could reduce pain levels in some people.

In an animal study, beta-caryophyllene was shown to reduce pain from nerve pain and inflammation. The researchers noted that this analgesic and anti-inflammatory effect may prove useful for treating long-term chronic pain due to the body showing no signs of developing a tolerance to these effects.

Other terpenes

The terpenes mentioned above among the most common terpenes that people are likely to come across. Over 25,000 different types of terpenes have been identified in nature, of which 200 are known to be produced by cannabis.

Link Between Terpenes and Cannabinoids​

Cannabinoids and terpenes share the same basic molecules, which means that they have similar construction and applications. For instance, they both interact with neurotransmitter receptors in order to create a variety of physical responses.​

One of the most important factors in terpenes’ potency is what scientists refer to as the entourage effect — this refers to the combined impact of a plant’s terpenes, cannabinoids, and other chemical compounds. Findings suggest that terpenes are most effective when consumed as a part of a whole plant or high-quality CBD product.​

It’s typical for a plant’s terpene levels to alter as the plant ages and/or dries. Although the terpene concentration can increase as the plant decays, it is typical for it to decrease, which is why dried herbs tend to lose their smell after a while.

Summary

Terpenes are the compounds responsible for the way most plants smell. They are not unique to cannabis, they are found in many other fruits, plants and herbs.

In some cases, smelling ingesting terpene-rich plants, specific essential oils, , or spending time in areas with high terpene content may provide some health benefits to humans.

Researchers must continue to study terpenes to understand their potential therapeutic and medicinal uses fully.

Disclaimer: This is not an inducement to use Medicinal Cannabis. Medical Cannabis doesn’t work for everyone, and it may not work for you. How Cannabis affects a person depends on many things, including their size, weight, age and health, dosage and tolerance, and the results can vary. Some people may experience side effects when taking Cannabinoid medication. The information provided by CDA Clinics is for educational and informational purposes only. For medical advice, please check with your doctor and request a referral.

Citations

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[1] https://www.sciencedirect.com/science/article/abs/pii/S0009279717310487