Terpenes: Not Just a Pretty Fragrance
Chemical composition of cannabis
When it comes to medicinal cannabis, the main therapeutic benefits of the plant are heavily-linked to molecules called cannabinoids. Varying concentrations of phytocannabinoids, such as cannabidiol (CBD) and tetrahydrocannabinol (THC), are present in a whole range of cannabis plants and products. They are associated with health benefits such as analgesia, anti-inflammation, improvements in mood, and many more.
But cannabinoids aren’t the only pharmacologically active molecules that can be extracted from cannabis. While there are over 100 different species of cannabinoids that can be found within the plant, molecules such as terpenes and flavonoids are also present within the chemical composition of cannabis.
With the endocannabinoid system and the effects of individual cannabinoids under constant investigation, researchers have proposed that these additional molecules could also play a part in the wide-ranging effects of cannabis. It is thought that terpenes, in particular, play a large role in contributing to the ‘Entourage Effect’. This phenomenon describes the way in which these chemical components work together synergistically to provide these health benefits.
Currently, there are lots of studies on various terpenes, the physiological effects they produce, and how they contribute to the Entourage Effect. But what exactly are terpenes?
Terpenes are aromatic oils that can be found in a wide range of organisms, including plants such as cannabis. There are over 100 different terpenes that have been identified in the cannabis plant, with each different strain of cannabis having a unique terpene composition.
Terpenes are formed inside cannabis trichomes and are responsible for the aroma and flavours of the plant. It is thought that the development of terpenes within plants is an evolutionary adaption to lure pollinators and to repel predators.
This isn’t their only function however, as scientists believe that terpenes can produce a wide variety of physiological effects within humans. As terpenes are hydrocarbons with a variable structure, these effects are often linked to their molecular ‘skeletons’. Units within their molecular structure are acted upon by various enzymes, which causes oxidation and added functionality.
For this reason, it should come as no surprise that terpenes are the primary components of essential oils. These aromatic oils are responsible for a plant’s regeneration, oxidation, defence mechanisms, and immunity. Furthermore, they have been extracted from plants and utilised for their medicinal purposes by humans for thousands of years.
As cannabinoids have received most of the attention from the scientific community, further research is required to understand the full extent of cannabis terpenes and their remedial effects. Even so, one thing that is clear is that cannabis terpenes support other cannabis-derived molecules in producing these effects. This is why they are included in so many full-spectrum cannabis extracts and products and, in some cases, completely isolated and sold separately.
Let’s explore some of the main terpenes found within the cannabis plant and cannabis-based medicinal products.
Myrcene is the most common terpene found within cannabis and is estimated to make up 20% of most commercial strain’s terpene profiles. In fact, close to 40% of all cannabis strains on the legal market are myrcene-dominant.
This terpene is also abundant in a range of plants and fruits, such as parsley, thyme, lemongrass, hops, and mango. Myrcene is recognisable by the earthy and musky balsam scent that it provides to these plants and also the peppery flavour it gives to hops in beer.
Myrcene has a long history of use as a sleep aid in some traditional medicines around the world. Teas that are infused with myrcene-rich lemongrass are used as a sedative in Mexico, and myrcene-rich hops preparations are commonly used as sleep aids in Germany.
Currently, there is no clinical evidence to support these claims, however, one study has found that high concentrations of myrcene may have a sedative effect on mice. As rodent studies don’t always translate perfectly into human-drug interactions, further research is needed in this area to determine the significance of these apparent sedative effects.
Another one of myrcene’s potential health benefits is anti-inflammation. A 2015 study found that myrcene had an anti-inflammatory influence on human cartilage cells while slowing deterioration and disease progression.
Myrcene also has antioxidant and anti-microbial properties, which are consistent with many other terpenes present in plants such as cannabis. Recent studies have also investigated myrcene’s anti-tumour properties and its ability to block the carcinogenic effects of certain toxins while protecting against DNA damage.
Caryophyllene, also referred to as beta-caryophyllene, is the second-most common terpene found in commercial cannabis strains and products. It can also be found in many herbs and spices, including black pepper, cinnamon, cloves, basil, oregano, and hops. It has a diverse aromatic profile that includes floral and earthy notes but is most commonly associated with the spicy aroma and flavour of black peppercorns.
Caryophyllene has displayed a wide variety of therapeutic benefits, with the most prominent being its anti-inflammatory and analgesic effects. This terpene’s anti-inflammatory effects could prove useful in the treatment of a range of conditions, such as arthritis, as seen in some rodent studies, and inflammatory bowel disease.
Caryophyllene has also shown promise as a sedative and diabetic aid. A 2012 study found that mice administered with caryophyllene experienced longer sleep times, and a 2014 study found that caryophyllene can help to balance the glucose levels of diabetic mice, in conjunction with standard diabetic medicines.
Limonene is the third-most common terpene found in commercial cannabis strains and products. It has a characteristic fragrance of zesty citrus and can be found in many fruits, such as lemon, lime, orange, and grapefruit. This popular scent is also included in many cosmetic and cleaning products.
Limonene is one of the most researched terpenes around, due to the variety of effects it can have on the immune systems of plants and humans. It has well-established anti-bacterial and anti-microbial effects and has also displayed potential in combatting mood disorders, inflammation, pain, and diabetes.
Essential oils that contain high traces of limonene often claim to have anxiolytic properties. Evidence for this claim was supported in a 2013 rodent study, where limonene was able to improve anxiety-like states in mice. Furthermore, inhalation of limonene vapour has been found to increase serotonin and dopamine levels in the regions of the brain that are associated with anxiety, depression, and OCD.
Several studies have also investigated limonene’s prospective anti-tumour properties. Limonene has proven somewhat effective at inhibiting the growth and metastasis of tumours in breast cancer, as well as promoting tumour apoptosis in lung, colon, and brain cancer. Even with these positive results, more evidence is needed to determine the efficacy of limonene in cancer treatment.
While pinene-dominant cannabis strains are uncommon, this is one of the most abundant terpenes in many different cannabis plants and products. As its name would suggest, pinene is responsible for the fragrance associated with pine trees. It can also be found in plants such as conifer trees, rosemary, dill, basil, and parsley.
There are two forms of pinene that exist naturally: alpha-pinene and beta-pinene. Alpha-pinene is the most abundant terpenoid found in nature and is thought to be more clinically relevant than beta-pinene, with researchers mostly interested in its neuroprotective effects. These effects could be beneficial in combatting conditions such as Alzheimer’s disease, amnesia, dementia, and cognitive dysfunction.
Another novel use for pinene is in the treatment of respiratory illnesses, such as chronic bronchitis. One study found that both types of pinene inhibited viral cell activity and acted as a bronchodilator in animal models.
Like other terpenes, pinene also has anti-inflammatory and anti-microbial properties. Pinene’s role as an anti-cancer agent is also under investigation, with both alpha-pinene and beta-pinene displaying tumour-inhibiting effects in various animal models.
Humulene is a fairly common terpene in numerous cannabis strains but is normally present in smaller quantities than the aforementioned terpenes. It shares some traits with caryophyllene, as they are both found in hops, with humulene being the main terpene responsible for their herbaceous aroma and the bitter taste of beer. Humulene can also be found in many herbs and spices such as ginseng, sage, and coriander.
Many essential oils contain humulene, and this terpene also has a history of use in some traditional medicines, such as ancient Chinese remedies that utilise Chinese ginseng and sage oil. As such, there are several studies on the therapeutic potential of this terpene, with promising results in displaying anti-inflammatory, anti-fungal, and anti-bacterial effects.
As is the case with other terpenes, humulene’s potential anti-tumour properties are also under investigation. Humulene is present in balsam fir oil, which has been studied to determine its efficacy in fighting cancerous cells. One study found that balsam fir oil may kill cancer cells by turning off their antioxidant processes and inhibiting tumour growth, but more research is required in this area.
Terpinolene is found in a variety of cannabis strains but is normally only present in small amounts. This terpene contributes to a diverse aromatic profile that contains floral, herbaceous, and citrus notes. This aroma is often referred to as a ‘fresh’ scent, which is why terpinolene is used as an additive in certain soaps and perfumes. Terpinolene can also be found in lilac, nutmeg, cumin, and apples.
Besides its scent, another reason terpinolene is included in many essential oils and soaps is due to its therapeutic benefits. These include anti-fungal and anti-bacterial effects. It has also been suggested that terpinolene is a popular additive in commercial cleaning products not just for its fresh scent, but also its ability to repel pests, such as mosquitoes and weevils.
There also several studies that detail some other potential benefits of terpinolene. A 2013 study found that terpinolene had potent anti-proliferative and anti-inflammatory effects. Another 2013 study investigated terpinolene’s effectiveness as a sleep aid when included in an essential oil and found that a sedative effect was present after nasal absorption. All of these effects require further research for these claims to be reliable.
Ocimene is another terpene that isn’t likely to be the dominant terpene in a cannabis strain’s profile but can sometimes be the second- or third-most abundant. This terpene produces a sweet, earthy, and herbaceous aroma with citrus undertones, making it a popular additive in some perfumes.
Outside of perfumes, ocimene can also be found in a variety of herbs and fruits, including hops, mint, parsley, tarragon, basil, bergamot, mangoes, and kumquats. Not everyone is a fan of this aroma, however. Similar to terpinolene, pests such as aphids and other insects steer clear of ocimene-containing cannabis species, which helps to explain why this terpene can sometimes be an additive in a range of insecticides.
Ocimene also has other uses, displaying antioxidant, anti-fungal, anti-inflammatory and anti-viral properties across several studies, as well as the potential for use as a decongestant. Another novel effect of ocimene that has been studied is its ability to inhibit key enzymes that are associated with conditions such as type 2 diabetes and hypertension.
There are very few cannabis strains that contain high concentrations of linalool, but it can still feature as the third- or fourth-most abundant terpene in some. Linalool isn’t just specific to cannabis though, it is common in over 200 types of plants. The most notable of these plants is lavender, as its characteristic smell is attributed to the presence of linalool. It can also be found in herbs and fruits, such as cinnamon, coriander, mint, cloves, lemons, and mandarins.
Lavender oil is an extremely popular essential oil, and linalool is a common constituent in a variety of commercial products due to the therapeutic benefits of this terpene, which have been extensively researched. Similar to many other terpenes, linalool has both anti-inflammatory and anti-microbial properties.
However, linalool’s most notable therapeutic benefits are its stress-relieving and sedative effects, which are the main reasons behind the popularity of lavender oil. A 2013 study also found that linalool in topicals can facilitate a decrease in breathing and heart rates, which are important in stress relief, while potentially boosting the immune system.
The potential of linalool as a therapeutic neurological agent is another research focus. The hope is that linalool could be beneficial in the treatment of Alzheimer’s disease, due to its ability to reverse the neurological and behavioural impairments in mice with this condition.
In order to create terpene-infused products, individual terpenes must first be extracted from cannabis plants. Terpene extraction methods are constantly being developed or improved, and are a crucial part of cannabis compound isolation. The technology and processes for extracting terpenes have become widely available to cannabis product manufacturers, who have benefitted from the R&D conducted by the fragrance industry.
Terpenes are delicate molecules, and they require a high degree of care in order to preserve their aromas, flavours and potential therapeutic effects. Conventional cannabis extraction methods can be unsuitable for these products and reduce the overall quality of the end product. There is more than one method of terpene extraction, with each having their own pros and cons. These methods are split into two categories: solvent-based and solventless.
Solventless extraction methods are the ones that have typically been used to create essential oils and perfumes for many years. The main solventless extraction method is steam distillation. In this process, the cannabis plant matter is placed over a container filled with boiling water. When steam starts to pass through the plant matter, the oils that contain terpenes are transported to a condensation flask, where this oil-water mixture begins to cool. The terpene-containing oils float to the top of the water, where they are easily collected.
As steam distillation doesn’t require a solvent, there is no risk of diluting the extract with external chemical residues. The major downside of this method is that it requires a significant amount of sustained heat. Any changes in temperature or timing can lead to the alteration or destruction of terpenes.
Solvent-based methods are usually more efficient when it comes to compound extraction. They utilise much lower boiling points and solvents such as butane, ethanol, nitrogen, and CO2. In order to reduce the potential of terpene degradation, vacuums are used to reduce heat.
The most popular solvent-based method amongst manufacturers is supercritical CO2 extraction. This method involves using heat and pressure to convert gaseous CO2 into a supercritical liquid, which is then used as a solvent. The liquid CO2 is passed through cannabis plant matter, resulting in the production of a resin concentrate. A vacuum drying oven is then used to refine this extract so that individual terpenes can be isolated and extracted.
The refining step is necessary to ensure the purity of these terpene extracts, as there should be no remaining traces of water or any other solvents. This method is often viewed as not just effective but safe and exempt from the quality issues that can arise when using solventless methods, such as steam distillation.
Full-spectrum extracts & terpene-infused products
After extraction, these terpenes can be sold in their isolated form, or as part of a concentrate containing other cannabis compounds. Most cannabis concentrates contain terpenes, along with a range of other potentially therapeutic molecules, such as cannabinoids and flavonoids. These products are known as full-spectrum extracts, and their goal is to retain all the desirable compounds within cannabis, in order to enhance any health benefits.
Another type of cannabis extract available on the market that contains terpenes are ‘high-terpene full-spectrum extracts’, also known as HTFSE. As the name suggests, these extracts have a higher concentration of terpenes than the average full-spectrum extract, with terpenes making up anywhere from 13% to 40% of their composition. For some consumers, these extracts can provide more therapeutic benefits and less intoxication than other full-spectrum extracts, but this is ultimately down to personal preference.
The development of processes that allow terpenes to be isolated and then extracted individually has lead to a variety of terpene isolate products hitting the market. For example, terpenes such as pinene and limonene can be sold separately and utilised in different ways. You can diffuse these terpene isolates, as you would with any other essential oil, or infuse them into a range of other products such as topicals, candles, and even vape cartridges.
In some cases, manufacturers will attempt to combine isolated terpenes according to specific ratios in order to imitate the terpene profile of different cannabis strains. These manufacturers can also combine different terpenes in order to enhance a certain therapeutic benefit that their product is trying to produce. For example, a product may contain high concentrations of caryophyllene, limonene, and humulene to enhance analgesic effects, or high concentrations of linalool and terpinolene to enhance sedative effects.
High concentrations of these terpenes are usually required to produce significant health benefits. Some cannabis strains can have low terpene concentrations, and, as they are fragile molecules, terpenes can be lost or damaged during the extraction process. To combat this, manufacturers often re-infuse isolated terpenes into their products to increase the concentration of terpenes and enhance their effects.
The bottom line on terpenes
While there is both anecdotal and clinical evidence to suggest that terpenes can provide a range of therapeutic effects, researchers are just beginning to scratch the surface of how terpenes interact with our bodies. It is clear that high concentrations are needed before any significant effects are felt, hence the inclusion of many additional terpenes in cannabis-derived medicinal products.
Future research will investigate how these terpenes can affect processes within our body on both an individual basis and when working together with other terpenes and phytochemicals. Through the unlimited combinations of potential synergistic effects, terpene-infused products will open up new pathways for cannabis research and medicinal product formulations.
These terpene-infused and terpene isolate products have taken the world by storm and are widely available in most markets. There is a wide range to choose from, so it shouldn’t be hard to find the right product for your needs.