Terpenes are aromatic compounds found in many plants. However, many people associate them with cannabis because cannabis plants contain high concentrations of terpenes.
These aromatic compounds create the signature scent of many plants, such as cannabis, pine, and lavender, as well as fresh orange peel. The scent of most plants is due to a combination of terpenes. In nature, these terpenes protect plants from animal damage or infectious agents.
However, terpenes can also offer some health benefits to the human body. As cannabis regulations become less stringent, scientists continue to research these potential benefits.
What are terpenes?
Terpenes are highly aromatic compounds that determine the smell of many plants and herbs such as rosemary and lavender, but also some animals.
Manufacturers use isolated terpenes to create the flavors and fragrances of many everyday products like perfumes, personal care products, and even food.
Terpenes play an important role in plants. In some plants, terpenes attract pollinators, while in other plants they elicit a powerful response to deter predators such as insects or animals in search of food.
Some terpenes play a protective role in the plant, helping it recover from damage; others act as part of the plant's immune system to fight off infectious germs.
Some people also use the term terpenoids. However, terpenes and terpenoids are not the same thing.
Terpenes are the natural form of these compounds when they are in the living plant.
On the other hand, when a plant dries and hardens, the terpenes oxidize and become terpenoids.
How are they different from cannabinoids?
Cannabinoids are chemical compounds in cannabis.
Cannabinoids, such as tetrahydrocannabinol (THC), activate receptors in the body's endocannabinoid system. This creates the “high” that people experience when consuming cannabis.
Cannabidiol (CBD) is another cannabinoid that is gaining popularity for its medicinal properties. Although CBD acts on some of the same receptors as THC, it affects them differently and does not induce euphoria.
While THC and CBD are the most well-known cannabinoids, they are just two of over 100 cannabinoids found in the cannabis plant.
The cannabis plant also contains terpenes, which are among the most abundant compounds found in nature.
Terpenes are primarily responsible for the smell of most plants and some animal compounds. However, some can also act on the endocannabinoid system in the body in a similar way to cannabinoids. The main difference is that the body absorbs and uses these compounds in different ways.
Do Terpenes Affect Humans?
Many terpenes are bioactive, meaning they can affect the body. This effect depends on the concentration of the terpene itself and how a person uses it.
Because terpenes create vibrant smells, they form the basis of many essential oils and are an essential part of many alternative therapies, such as aromatherapy. Inhaling the scents of some plants and essential oils can affect a person's mood and stress levels.
Some people believe that terpenes affect or enhance the high a person gets from consuming cannabis. This is called the "entourage effect," meaning that terpenes enhance or alter the effects of THC and CBD in the body.
Some research supports these claims. For example, a review in Frontiers in Neurology found that people with epilepsy who took an extract rich in CBD had better symptoms and fewer side effects than those taking pure CBD. This suggests that the other components of cannabis, such as terpenes, can affect the way the body uses CBD.
There is a lot of medical research on isolated terpenes themselves, and some may even find their way into medicinal applications. A study in the journal Chemico-Biological Interactions points out that many terpenes have been shown to have beneficial effects on the body.
Although there are many terpenes in nature, scientists have only studied a handful of them.
Examples of more well-known terpenes are:
Limonene is a common terpene that most people can identify by its smell. As the name suggests, limonene gives the citrus-like smell to the peels of fruits like lemons and oranges.
A study in the journal Chemico-Biological Interactions notes that limonene possesses the following therapeutic properties:
Limonene appears to modulate the behavior of certain immune cells, which can protect the body from a range of diseases.
Pinene is another naturally abundant terpene. There are two forms of pinene: a-pinene and b-pinene. Pinene provides the fresh, bright scent of many plants, including pine needles, rosemary, and basil. Pinene may also have some therapeutic benefits.
Shirin-yoku, which means "forest bathing," is a Japanese therapy that involves taking leisurely walks in the forest, soaking up the atmosphere and enjoying the scent. Shirin-yoku can have preventive and strengthening effects on the human psyche and physiology.
A study in Acta Salus Vitae states that the amount of pine in the air of a healthy forest is sufficient to be therapeutic. Pinene has a bronchodilator effect and allows more air into the lungs. It also has anti-inflammatory effects and can act against some infectious agents when inhaled.
Linalool is most commonly found in the lavender plant and is what gives the flower its intense fragrance. Linalool is one of the most important compounds used in aromatherapy and is responsible for the calming effects many people feel when smelling lavender or its essential oil.
A study published in Colloids and Surfaces B: Biointerfaces notes that linalool can act on the body in a variety of ways due to a number of properties, including:
- Anti-anxiety drugs
Linalool appears to work on the body, but researchers need to study its effects further to understand how people can use it for their health.
Myrcene is a terpene commonly found in plants like hops, lemongrass, and thyme. The flowers of the cannabis plant also contain myrrhen.
Mycren is a powerful antioxidant. A study in Sourcein mice concludes that mycrene may help protect the brain from oxidative damage after a stroke.
Another study in mice found myrrene to have a similar protective effect on heart tissue. The researchers determined that mycrene could be a useful treatment alternative after an ischemic stroke.
However, it is important to remember that very high concentrations of myrcene, up to 200 milligrams (mg) per kilogram (kg) of body weight, were used in these studies.
Another study, conducted on a cell model of osteoarthritis, found that myrrene appears to have anti-inflammatory effects and may prevent some cartilage cells from breaking down. This could make it a useful remedy for osteoarthritis.
Beta caryophyllene is found in many herbs and vegetables such as cloves and black pepper.
Similar to other terpenes, beta-caryophyllene may have anti-inflammatory effects on the body that could reduce pain in some people.
In an animal study that was conducted, beta-caryophyllene reduced pain due to inflammation and nerve pain. Researchers noted that this anti-inflammatory analgesic effect could be of use in the management of long-term chronic pain, as the body shows no signs of developing tolerance to these effects.
Humulene is a main component of the hop plant. It is also found in other plants such as cloves and ginger.
A study published in Frontiers in Pharmacology suggests that terpenes, including humulene, may prevent allergic reactions and asthma. In animal models, humulene reduced allergic inflammation in the airways. This could make it a helpful compound for future natural asthma treatments.
Another study in the journal Food an Chemical Toxicology found that humulene may also have protective effects in some cells. This protective effect could protect against cancer. However, these are only preliminary findings, and researchers need to investigate further the effects of humulene to support these claims.
The above terpenes are some of the most abundant active terpenes you are likely to encounter. Some other common terpenes are:
Terpenes are the compounds responsible for the smell of most plants. They are abundant in cannabis and many other plants, fruits, and herbs.
They can play a role in the health and survival of the plants in which they are found.
In some cases, smelling certain essential oils, ingesting terpene-rich plants, or staying in areas high in terpenes can provide health benefits to humans.
Researchers need to study terpenes further to fully understand their potential therapeutic and medicinal uses.