There are 50+ cannabinoids in cannabis, each with a unique chemical structure and potential effect(s) when consumed. The science of cannabinoids becomes complex when considering the nature of how cannabinoids interact with the ECS (endocannabinoid system).
Human Endocannabinoid System
The Endocannabinoid System (ECS) is the biochemical system of the human body that interacts with cannabinoids.
What does the ECS do? Though the ECS has not been exhaustively studied, we do know that it is involved in many physiological and cognitive processes governed by systems such as the central nervous system, cardiovascular functions, gastrointestinal functions, respiratory functions, certain hormone and peptide regulation, and immune functions.
What is the ECS made up of? The ECS is primarily composed of "endocannabinoid receptors" and "endocannabinoids". Endocannabinoid receptors are very small biochemical structures found on a variety of different cells that transmit a signal which can initiate certain physiological and cognitive functions. Endocannabinoids are the native chemicals produced by the body that cause the transmission of a signal at the endocannabinoid receptors.
How do cannabinoids fit into this? Not to be confused with endocannabinoids (which are produced by the human body), cannabinoids (also known as "phytocannabinoids" or “plant cannabinoids”) are the chemicals produced by the cannabis plant. It just so happens that these chemicals interact with the human endocannabinoid receptors in a very similar manner to endocannabinoids.
There is a wide variety of cannabinoids, most of which have not been extensively scientifically stidied and are thus not well understood. Cannabinoids act on both the CB1 and CB2 receptors (endocannabinoid receptors), present in the brain and the periphery. Binding to (interacting with) these receptors initiates pathways that directly affect a multitude of cognitive and physiological processes.
(+)-trans-Δ9-tetrahydrocannabinol (THC), C21H30O2, is the primary and best known psychoactive cannabinoid in cannabis which makes up anywhere from 12% to 30% of the plant's dry weight. THC primarliy acts on the CB1 receptors in the central nervous system. Although many cannabinoids contribute to the psychoactive effects experienced when consuming cannabis, in many strains, the effects of THC predominate. Because of this, THC is largely responsible for euphoria, changes in sensory experiences, changes in mood, alterations in perception, changes in anxiety, and relaxation.
Cannabinol (CBN), C21H26O2, is a non-psychoactive compound found only in trace amounts of the cannabis plant. CBN primarily acts on the CB1 and CB2 receptors but has a greater binding affinity for CB2. Although much less is known about CBN than THC, many studies have demonstrated its sedative effects. For those of us that prefer a clear minded night of "couch-lock", CBN is ideal.
Cannabidiol (CBD), C21H30O2, is a non-psychoactive compound that makes up 1% - 4% of the plant's dry weight. CBD acts on the CB1 and CB2 receptors, but binds with a higher affinity to CB2. Although there are many benefits to taking CBD, it is most often used to treat anxiety, insomnia, and drug withdrawals, decrease incidences of seizures, and to reduce inflammation.
Tetrahydrocannabivarin (THCV), C19H26O2, is a psychoactive compound when consumed in appropriate doses. Although not well characterized, it is thought to act on the CB1 receptor. Some believe that THCV raises the siezure threshold for those with epilepsy. In contrast to THC, THCV actually curbs appetite. Some think that this can potentiate the effects of THC.
Cannabichromene (CBC), C21H30O2, is a non-psychoactive cannabinoid and is structurally similar to the other cannabinoids. It has anti-antiinflammatory and anti-viral effects and may contribute to the overall anelgesic effects of cannabis.
Although much less prevalent in the cannabis plant than cannabinoids, terpenes are the chemicals (also found in many different plants, foods, and drinks) that give cannabis smell and flavor. Very little research has been conducted on the therapeutic effects of terpenes when combined with cannabinoids, but it is thought that when consumed with cannabinoids they can modify the effects produced in the body.
β-Caryophyllene: β-caryophyllene (BCP) can be found in abundance in some samples of Cannabis, while being largely absent in others. This terpene is found in a variety of other plants such as clove, lavender, and rosemary. Interestingly it has a surprising affinity for the human cannabinoid receptor 2 (CB2) making it the only phytocannabinoid found outside of the Cannabis genus. BCP has been shown to have strong anti-inflammatory properties in mice dependent upon the presence of the CB2 receptor. Given its potential neuroprotective properties it shows potential as a treatment for multiple sclerosis, Parkinson’s disease, and other neuroinflammatory diseases, but has yet to be investigated outside of mouse models.
Linalool: Linalool (LNL) is generally not a major terpene in cannabis, but can be present in a sizeable fraction of some strains. LNL is a predominant terpene in Lavender where it can constitute ~80% of present terpenes. Extensive mouse model experiments have shown LNL possesses a variety of biological activities as a sedative, anti-nociceptive (pain reliever), anti-inflamatory, and is suggested to possess many further properties. These effects have however, not been demonstrated in humans.
α-Pinene: α-Pinene (α-PN) outside of the context of Cannabis is the most commonly encountered terpene in nature, being found in large amounts in conifer trees. While it is used as base materials for synthesis of synthetic CB2 interacting-compounds, α-PN itself has no direct affinity for cannabinoid receptors. Studies have suggested an anti-tumor link, but the data is yet to be conclusive. Mouse model experiments have shown α-PN to be both an anti-inflammatory and anti-oxidant. Mouse models also show both anti-anxiety and sedative effects, and α-PN has been shown to function as a bronchodilator (opens up airways) in humans. These effects, with the exception of bronchodilation, have not been demonstrated in humans.
Myrcene: Myrcene (MYR) is the terpene generally found in the largest abundance in cannabis, upwards of 60-80% of present terpenes. Unlike cannabinoids myrcene is found in a variety of other plants including hops, lemon grass, wild thyme, and basil. Testing in mice, rats, and tissue culture have shown a wide variety of positive effects including protecting brain, heart, and skin tissue from oxidative and inflammation damage. Additionally, anti-nociceptive effects have been shown, i.e. pain reducing. These effects have not however been tested clinically in humans.
Limonene: Limonene (LIM) is sometimes the major terpene in Cannabis, but it is always the major terpene in citrus fruits. Cell culture and mouse model experiments suggest that LIM can reduce both inflammation and oxidative stress, as well as stress and depression. LIM has been evaluated in clinical trials for anti-cancer properties. However, outside of the clinical trials, little human investigations as to the activity of LIM have been performed.