Published: May 24th, 2018
During a conversation or brief internet search regarding cannabis, it’s likely that two cannabinoids are going to be mentioned: THC and CBD. Both of these compounds are known for their plethora of health benefits and potential to treat a vast array of conditions. THC is also responsible for the psychoactive high produced when marijuana is smoked, making it extremely popular among recreational users. CBD has risen to fame as a non-psychoactive element of the cannabis plant, and is legal in many countries where THC is not.
Despite the popularity of these two, cannabis research over the last few decades has been accelerating. Hundreds of compounds have been isolated from the cannabis plant, and at least 113 of these are cannabinoids, belonging to the same molecular family as THC and CBD. Many of these have been studied to some extent, with 70 of them having been well-described. However, revealing their true potential is dependent upon future in-depth study and analysis.
Cannabinoids are found within a viscous resin that is produced by small mushroom-shaped glands found on the flowers and leaves of cannabis/hemp plants known as trichomes. These small chemical factories are also responsible for the aromatic molecules that give cannabis its unique and diverse aromas, known as terpenes.
Cannabinoids are unique to cannabis and found nowhere else in nature, making the plant even more unique.
Some of these compounds are found within raw cannabis in their acidic form. THC is found as THCA and CBD is found as CBDA. When heat is applied, these molecules undergo a chemical reaction in which a carboxyl group is removed, resulting in the formation of THC and CBD. This process is known as decarboxylation.
Cannabinoids have a variety of effects, with some acting quite differently than others physiologically. Two common themes amongst most cannabinoids are their medicinal potential and how they interact with the body. Most cannabinoids appear to activate receptors sites within the body's endocannabinoid system. They achieve this mechanism of action due to their structural similarities with cannabinoids that are produced by the body, known as endocannabinoids.
This system is made up primarily of CB1 and CB2 receptors, which are found throughout the body on cells occupying the nervous system and immune system.
CBD is the major non-psychoactive cannabinoid found within cannabis and hemp derivatives. The cannabinoid is found in varying levels within cannabis strains bred for recreational and medicinal purposes, and is also sourced from industrial low-THC hemp. CBD has gained massive traction within the domains of medicine/health and wellness due to its therapeutic benefits and medical potential, which have been increasingly documented in scientific literature.
CBD has been found to exhibit anti-anxiety effects, possibly due to acting upon the limbic and paralimbic regions of the brain. The compound has also displayed anti-inflammatory, antioxidant, and immunomodulating actions. Research has also identified antiepileptic/anticonvulsant effects, which have been reported in large numbers in famous anecdotal accounts. CBD also exhibits antitumour activity in vitro.
The recent rise in popularity orientated around this cannabinoid has led breeders to develop strains that are becoming much higher in CBD, with lower levels of THC. Some of the highest CBD strains available provide a 1:1 ratio of CBD to THC, are much less psychoactive, and are often used to make extracts for medicinal uses. Non-psychoactive CBD is now even being administered to pets as a safe way to boost their daily health and wellness.
CBDA is the acidic precursor of CBD that exists within raw and processed plant matter prior to the process of decarboxylation. CBDA was the first cannabinoid acid to be isolated, having been first described in 1955. There is a lack of study regarding the complete actions of CBDA, and the pure compound has rarely been analysed for its physiological effects.
CBDA has been found to exhibit antimicrobial activity. During a study conducted on the constituents of hemp seed oil, extracts containing higher levels of CBDA where found to have more potent antimicrobial effects. However, it is known that hemp seeds do not contain cannabinoids, therefore, the cannabinoid content in this case is deemed to be the result of contamination.
CBDA has also been reported to exhibit anti-inflammatory and antiproliferative effects.
CBN has played a crucial role in the development of cannabis science, being the first ever cannabinoid to be isolated from the cannabis plant. This discovery occurred back in 1940. Interestingly, CBN is not formed via the metabolic process of the cannabis plant. Instead, the cannabinoid is formed due to the degradation of THC that occurs during drying, storing, and heating. CBN is weakly psychoactive, yet it may play a role in the effects felt after consuming cannabis. CBN is likely to interact with the effects of THC and may actually mediate its effects.
Aside from its minimal psychoactive properties, CBN has been found to possess several qualities that give it medicinal potential in-keeping with practically all studied cannabinoids. CBN exhibits significant anticonvulsant effects, making it a candidate for study when it comes to seizure and epilepsy therapeutics.
CBN also displays sedative effects, has the ability to decrease heart rate without affecting coronary blood flow, inhibits platelet aggregation, and decreases intestinal motility.
CBG is one of the major cannabinoids found within the cannabis plant, and we have it to thank for the existence of many of the cannabinoids we know and utilise. CBG is actually the precursor to many other cannabinoids, and is converted via enzymatic activity into THC, CBD, and other cannabinoids. This is one reason why CBG is present in such small amounts in hemp during the harvest window, as chemical reactions have converted the molecule into other members of the cannabinoid family.
As well as its important precursor functions, CBG has been found to display therapeutic action in its original cannabinoid form prior to conversion. CBG has a slight affinity for CB1 receptors, reported to be equal to that of CBD.
CBG has been shown to possess both analgesic and anti-inflammatory actions, placing it in the same category as CBD as a non-psychoactive cannabinoid with therapeutic potential. Research has also shown CBG to exhibit antitumour functions, and to inhibit platelet aggregation.
Very little research has been conducted upon CBC. However, the cannabinoid is found in significant concentrations within cannabis in its acidic form, CBCA. CBC displays sedative effects, and has also shown some analgesic effects in mice. Further, it may help boost the analgesic action of THC when both cannabinoids are used together.
THC is one of the most famous cannabinoids, and is the primary substance that gives cannabis its psychoactive effects. THC is the subject of much controversy and debate in many countries due to its psychoactive nature, and remains mostly illegal despite its proven medicinal properties.
THC exists in various different forms. Prior to decarboxylation, THC exists in its acidic form known as THCA. THCA is non-psychoactive and has been shown to generate medicinal actions. This cannabinoid acid has displayed neuroprotective properties, making it a candidate for the development of drugs to treat neurodegenerative diseases. THCA also has anti-inflammatory, antiemetic, and antiproliferative effects.
THC is formed after THCA is subject to adequate heat, such as when smoked. THC, or delta-9-tetrahydrocannabinol, binds to both CB1 and CB2 cannabinoid receptors. THC is known to have sustain sensory, somatic, and cognitive effects on humans.
The psychoactive effects of THC may be medicinal for some users, with research showing potential anxiolytic and antidepressant effects.
THC is also recognised to decrease intraocular pressure and improve blood circulation in the eyes, presenting therapeutic potential in cases of glaucoma. THC also displays immunomodulating, anticonvulsant, and antitumour activity. The cannabinoid also shows promise for irritable bowel syndrome and Crohn's disease.
Delta-8-THC is a positional isomer of delta-9-THC. It has similar physiological effects, but is less potent when it comes to psychoactivity. This cannabinoid is believed to be produced in a similar way to CBN, in that it isn’t produced by the metabolic processes of cannabis plants, but is the result of degradation of delta-9-THC.
When tested in mice, delta-8-THC causes increased food consumption, leading to the possibility that it is responsible for the “munchies” when cannabis is ingested.
THCV, or tetrahydrocannabivarin, is molecularly similar to THC, yet has a shortened side chain. Evidence suggests that THCV binds to both CB1 and CB2 receptors. Although research is still in its infancy, THCV has displayed medicinal potential and may help to aid in the treatment of diseases such as epilepsy.