Profiling terpenes
Terpenes are often overlooked in cannabis, as the cannabinoids get most of the attention; however, terpenes have long been an important class of compounds for those seeking various types of botanical therapies. Terpenes are the compounds associated with the many different flavors and aromas found in cannabis and other botanicals.
Terpenes are essentially essential oils
In fact, while many people may not be as familiar with the term terpenes, almost everyone has heard of essential oils. Essential oils are essentially terpene mixtures. Terpenes are made from isoprene units in the methylerythritol pathway. Most terpenes in cannabis are either mono terpenes, made from geranyl pyrophosphate (GPP), or sesquiterpenes, made from farnesyl pyrophosphate (FPP). The difference is that GPP has 2 isoprene units and FPP has 3 isoprene units.
In the formation of terpenes, positive charges are created on carbon atoms which become the driving force for the inter- and intramolecular reactions that result in terpenes. This explains both why the terpenes are such a diverse class of biosynthetic compounds, as well as why there are so many key similarities between the various terpenes made in plants.
The fact that terpenes are so ubiquitous throughout the plant kingdom means that there is often more known about the terpenes in cannabis than many of the cannabinoids. This is because for every terpene found in cannabis plants, you are sure to find some other plant that also produces the same terpene. Since essential oils have long been studied for their therapeutic effects, often associated with aromatherapy, there is often plenty of information to find on a wide variety of terpenes. Here, we will highlight a few of the most common terpenes found in cannabis strains.
Myrcene is the most common terpene found in cannabis, and it is often associated with having a very musky taste and smell. Not only is myrcene found in a wide variety of cannabis strains, but for many strains it is also the terpene found in the highest amount among the entire terpene profile. Some have compared the flavor and aroma to the forest itself as the taste tends to be very woody and the aroma very clove-like. The smell of myrcene is quite appealing and it is often used as a fragrance for products such as soaps and detergents. Chemically speaking, myrcene is one of the many monoterpenes made from GPP.
Myrcene is the most common terpene in cannabis
Myrcene is found in a wide range of plants: from cannabis and hops, to mangoes, lemongrass, cardamon and basil. In cannabis strains, the amount of myrcene in the terpene profile can be as high as 78%, such as in the blueberry strain. Other strains that can be found containing high levels of myrcene include Blue Dream, OG Kush and Grand Daddy Purps. Hops strains have also shown myrcene making up more than 50% of the overall terpene profile. This can be observed in the hint of peppery flavor in some beers.
Myrcene has a variety of effects on the body
While it has been claimed that myrcene has sedative properties, the evidence for this seems to be lacking. However, there are a variety of biochemical responses that myrcene does effect. In cannabis based mixtures, myrcene has shown to contribute to the entourage effect through modulation at the TRPV1. This is a Transient Receptor Potential ion channel receptor that is associated with analgesia. In other studies involving mice, myrcene has shown the potential for increasing the stimulation of the a2 adrenal receptors by their natural binding molecule.
Limonene is another very common terpene found in cannabis that is easily identified for its citrus like scent and flavor. As the name would suggest, the smell of limonene is very lemon-like. Indeed, it is the presence of limonene that contributes to the taste and smell of many citrus fruits such as lemons, limes and oranges. “Invigorating” and “refreshing” are words commonly used to describe the smell of limonene. It is also quite frequently used in cleaning agents. The structure of limonene is quite similar to that of myrcene, and like myrcene, it is a monoterpene made from GPP.
Limonene is packing the flavor in these strains
Limonene is found in a wide variety of strains, and is one of the more commonly found terpenes in cannabis. Unsurprisingly, many fruity flavored strains contain high amounts of limonene, including Lemon OG, Strawberry Banana and Dos Si Dos. In the strains Blackberry Kush, Cherry Chem and Sour Diesel, limonene is the second most common terpene following myrcene; making up around 10% of the terpene content of each. In White Cookies, limonene is the terpene with the highest concentration, making up around ⅓ of the terpene content. Even more impressive is the 56% of terpene content found in the famous strain Girl Scout Cookies. As impressive as all of this may sound, we can compare this to the 97% of limonene in orange rinds and lemon peels to see that citrus fruits still dominate in limonene production.
The effects of limonene include regulation of key proteins
Fortunately though, the prevalence of limonene in other plants and therefore common everyday products, means that there is quite a bit known about this terpene. Limonene has been shown to affect a number of biochemical pathways, each with varying biological effects; this includes protecting healthy cells and aiding in the programmed cell death of unhealthy cells. Limonene has also shown to affect the expression levels of critical cell signalling proteins called Ras and Raf. These cell signalling proteins are a vital part of the signalling cascades involved with the g-coupled protein receptors class of cell receptors, to which both of the endocannabinoid receptors belong.
Although not commonly found as the dominant terpene in cannabis strains, linalool is nevertheless found in small amounts in a wide variety of cannabis strains. Known for its floral scent, linalool is perhaps most noted for its contribution to lavender oil, as it typically makes up around 30-50% of the lavender oil aroma profile. Chemically, linalool is in a special class of terpenes called terpineols, due to the presence of an alcohol group on the compound. It is still a monoterpene because it is still made from GPP, however it is slightly different because the final positive charge is satisfied by electrons from water rather than from a proton loss. This final cation quenching step is what differentiates the fates of myrcene and linalool.
That floral linalool flavor is found in these strains
While linalool is not typically the dominant terpene found in most cannabis varieties, it is still found in a number of strains that you may be familiar with. Unsurprisingly, the strain Lavender has high amounts of linalool. As does the strain Sour OG, whose terpene profile is approximately ¼ linalool. As mentioned, however, this is still less than what is found in the lavender flower.
Linalool plays a role in regulating apoptotic proteins
Like limonene, linalool has shown to have important effects on programmed cell death (apoptosis) pathways which are vital to healthy tissue maintenance. Linalool does this through different mechanisms than limonene however, as linalool has been shown to increase the genetic expression of Bax and Bak, both of which are important apoptosis activators. Caspase proteins also play an important part in the regulation of apoptosis, and linalool has been shown to affect the activity of these proteins as well.
Like limonene, just the name pinene almost immediately makes one think about the scent of its namesake. Even when just hearing the name pinene, it’s hard not to immediately think of the refreshing smell of pine trees in the forest.The invigorating pine smell given by pinene has been used extensively in crafting the scent for air fresheners and cleaning products. Also like limonene and myrcene, pinene is yet another one of the terpenes that falls into the monoterpene category.
Pinene can be found all over the place
Similar to what we saw in the case of linalool, pinene is rarely the dominant terpene found in cannabis strains, however it is very common as a secondary terpene. Pinene is the dominant terpene in the strain Bubba Hash however, as it makes up 48% of the terpene content. Other strains with high amounts of pinene include Green Crack and Purple Punch. Overall pinene is perhaps the most common botanical terpene in the world due to the high amounts produced by conifers. The pine needles strewn across the forest floor make pinene the official scent of the outdoors.
Pinene a potent antioxidant
Given how common pinene is throughout nature, it is no surprise that it has been used as an herbal therapy dating back to the beginnings of Traditional Chinese Medicine. Pinene has shown to have effects in antioxidant and antiinflammatory pathways. In antioxidant pathways pinene has the effect of increasing the production of several important antioxidant enzymes including CAT and SOD. In the antiinflammatory pathways pinene acts to reduce the expression of COX-2 in certain mouse models.
Breaking from what we have seen so far, we will look at a couple of the sesquiterpenes. Caryophyllene is the most common sesquiterpene found in cannabis strains, and is overall right behind myrcene as one of the most common terpenes found in cannabis. Caryophyllene is a very unique terpene due to its chemical structure. Caryophyllene has a 4 carbon ring structure that is uncommon. As such caryophyllene is able to bind to CB2 receptors in the endocannabinoid system making it the only phytocannabinoid that is made in plants other than cannabis!
Caryophyllene, the most common phytocannabinoid in the plant kingdom
Caryophyllene’s ability to interact with CB2 receptors makes it a very unique terpene. The fact that it is also found in other plants makes it a very unique phytocannabinoid. Caryophyllene is found in hops at 15% of the total terpene content, but is also found in a wide variety of other plants including pepper, rosemary, and cloves. In cannabis, caryophyllene can be found as the predominant terpene in some strains as seen in Gorilla Glue, where it is present as high as 64% of the total terpene content. Other strains that have high ratios of caryophyllene include Death Star, Chemdog, Bubba Kush and one of my all time favorite strains Master Kush!
The unique CB2 agonism of Caryophyllene
As mentioned, caryophyllene interacts with the CB2 receptors of the endocannabinoid system in an agonistic way. These CB2 receptors are spread throughout the peripheral nervous system, and play a role in inflammation pathways. Aside from the interactions with CB2 receptors, caryophyllene has shown to have effects in other cell processes. There are a number of proteins involved in cell cycle regulation that are affected by caryophyllene, including p53, caspase 8 and caspase 9. These proteins all ensure the programmed cell death at the end of a cell’s life cycle.
Having a structure very much like caryophyllene, humulene is a sesquiterpene that is common in cannabis strains. Unlike caryophyllene however, it has not yet shown the ability to interact with the CB2 receptors. Humulene has an earthy aroma and is found in the spices coriander and basil. Hops also has high amounts of humulene, and any time a craft beer drinker raves about how hoppy a beer is, it is humulene to which they should be singing their praise.
Humulene for your taste, your vapes and your space
Overall humulene is a rather common terpene in the plant kingdom. Humulene is often the predominant terpene in many of the hemp cannabis varieties, having ratios as high as 52% of the total terpene content. Not only is humulene found in the hemp strains of cannabis however, other cannabis strains that are high in humulene include Headband, White Widow, and Sour Diesel. Outside of cannabis and culinary spices, the desert brush commonly burned in ritual cleansings, sage, is also high in humulene.
Humulene displaying some similar effects
Similarly to what we saw in some of the other terpenes common in cannabis, humulene has shown to have a variety of effects in pathways associated with inflammation and healthy cell cycling. Like we saw in pinene, in the inflammation pathway humulene interacts the COX-2, which is a target of non steroidal anti inflammatory drugs. Given the similarities between so many of the terpenes it is not surprising that they would work in similar pathways. Humulene also affects programmed cell death through regulation of caspase proteins like we saw in caryophyllene and linalool.
Final thoughts
Terpenes are common throughout the plant kingdom, and are responsible for the many smells and tastes of nature. From the refreshing zest of citrus fruit to the relaxing comfort of lavender, we have terpenes to thank for it all. In a world where more and more cannabis consumers are purchasing their cannabis products based on THC content, don’t overlook the value of terpenes! Not only do they contribute to the entourage effect, but they are also responsible for the amazing smells and tastes of your favorite cannabis strains.
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