Tetrahydrocannabinol (THC) is a cannabinoid found in cannabis. It is the principal psychoactive constituent of cannabis and one of at least 113 total cannabinoids identified on the plant. Although the chemical formula for THC (C21H30O2) describes multiple isomers, the term THC usually refers to the delta-9-THC isomer with chemical name (−)-trans-Δ9-tetrahydrocannabinol. It is a colorless oil.
Cannabinoids are several structural classes of compounds found in the cannabis plant primarily and most animal organisms or as synthetic compounds. The most notable cannabinoid is the phytocannabinoid tetrahydrocannabinol (THC) (delta-9-THC), the primary psychoactive compound in cannabis. Cannabidiol (CBD) is also a major constituent of temperate cannabis plants and a minor constituent in tropical varieties. At least 113 distinct phytocannabinoids have been isolated from cannabis, although only four have been demonstrated to have a biogenetic origin. It was reported in 2020 that phytocannabinoids can be found in other plants such as rhododendron, licorice and liverwort, and earlier in Echinacea.
Cannabinoid receptors, located throughout the body, are part of the endocannabinoid system of vertebrates– a class of cell membrane receptors in the G protein-coupled receptor superfamily. As is typical of G protein-coupled receptors, the cannabinoid receptors contain seven transmembrane spanning domains. Cannabinoid receptors are activated by three major groups of ligands:
Cannabinol (CBN) is a mildly psychoactive phytocannabinoid that acts as a low affinity partial agonist at both CB1 and CB2 receptors. This activity at CB1 and CB2 receptors constitutes interaction of CBN with the endocannabinoid system (ECS).
Cannabidiol (CBD) is a phytocannabinoid, one of 113 identified cannabinoids in cannabis plants, along with tetrahydrocannabinol (THC), and accounts for up to 40% of the plant's extract. Medically, it is an anticonvulsant used to treat multiple forms of epilepsy. It was discovered in 1940 and, as of 2022, clinical research on CBD included studies related to the treatment of anxiety, addiction, psychosis, movement disorders, and pain, but there is insufficient high-quality evidence that CBD is effective for these conditions. CBD is sold as an herbal dietary supplement and promoted with yet unproven claims of particular therapeutic effects.
Tetrahydrocannabivarin is a homologue of tetrahydrocannabinol (THC) having a propyl (3-carbon) side chain instead of pentyl (5-carbon), making it non-psychoactive in lower doses. It has been shown to exhibit neuroprotective activity, appetite suppression, glycemic control and reduced side effects compared to THC, making it a potential treatment for management of obesity and diabetes. THCV was studied by Roger Adams as early as 1942.
Cannabivarin (CBV), also known as cannabivarol, is considered a non-psychoactive cannabinoid — it does not produce the euphoric side effects found in THC. Minor amounts of CBV are found in the hemp plant Cannabis sativa. It is an analog of cannabinol (CBN) with the side chain shortened by two methylene bridges (-CH2-). CBV is an oxidation product of tetrahydrocannabivarin (THCV, THV).
11-Hydroxy-Δ9-tetrahydrocannabinol, usually referred to as 11-hydroxy-THC is the main active metabolite of tetrahydrocannabinol (THC), which is formed in the body after Δ9-THC is consumed.
Cannabigerol (CBG) is a non-psychoactive cannabinoid and minor constituent of cannabis. It is one of more than 120 identified cannabinoids found in the plant genus Cannabis. The compound is the decarboxylated form of cannabigerolic acid (CBGA), the parent molecule from which other cannabinoids are biosynthesized.
Δ9-Tetrahydrocannabutol is a phytocannabinoid found in cannabis that is a homologue of tetrahydrocannabinol (THC), the main active component of Cannabis. Structurally, they are only different by the pentyl side chain being replaced by a butyl side chain. THCB was studied by Roger Adams as early as 1942
An N-acylethanolamine (NAE) is a type of fatty acid amide where one of several types of acyl groups is linked to the nitrogen atom of ethanolamine, and highly metabolic formed by intake of essential fatty acids through diet by 20:4, n-6 and 22:6, n-3 fatty acids, and when the body is physically and psychologically active,. The endocannabinoid signaling system (ECS) is the major pathway by which NAEs exerts its physiological effects in animal cells with similarities in plants, and the metabolism of NAEs is an integral part of the ECS, a very ancient signaling system, being clearly present from the divergence of the protostomian/deuterostomian, and even further back in time, to the very beginning of bacteria, the oldest organisms on Earth known to express phosphatidylethanolamine, the precursor to endocannabinoids, in their cytoplasmic membranes. Fatty acid metabolites with affinity for CB receptors are produced by cyanobacteria, which diverged from eukaryotes at least 2000 Million years ago (MYA), by brown algae which diverged about 1500 MYA, by sponges, which diverged from eumetazoans about 930 MYA, and a lineages that predate the evolution of CB receptors, as CB1 – CB2 duplication event may have occurred prior to the lophotrochozoan-deuterostome divergence 590 MYA. Fatty acid amide hydrolase (FAAH) evolved relatively recently, either after the evolution of fish 400 MYA, or after the appearance of mammals 300 MYA, but after the appearance of vertebrates. Linking FAAH, vanilloid receptors (VR1) and anandamide implies a coupling among the remaining ‘‘older’’ parts of the endocannabinoid system, monoglyceride lipase (MGL), CB receptors, that evolved prior to the metazoan–bilaterian divergence, but were secondarily lost in the Ecdysozoa, and 2-Arachidonoylglycerol (2-AG).
Tetrahydrocannabinolic acid is a precursor of tetrahydrocannabinol (THC), an active component of cannabis.
The entourage effect is a hypothesis that cannabis compounds other than tetrahydrocannabinol (THC) act synergistically with it to modulate the overall psychoactive effects of the plant.
Tetrahydrocannabiphorol (THCP, pronounced ) is a potent phytocannabinoid, a CB1 and CB2 agonist which was known as a synthetic homologue of THC, but for the first time in 2019 was isolated as a natural product in trace amounts from Cannabis sativa. It is structurally similar to Δ9-THC, the main active component of cannabis, but with the pentyl side chain extended to heptyl. Since it has a longer side chain, its cannabinoid effects are "far higher than Δ9-THC itself." Tetrahydrocannabiphorol has a reported binding affinity of 1.2 nM at CB1, approximately 33 times that of Δ9-THC (40 nM at CB1).
Cannabigerolic acid (CBGA) is the acidic form of cannabigerol (CBG). It is a dihydroxybenzoic acid and olivetolic acid in which the hydrogen at position 3 is substituted by a geranyl group. It is a biosynthetic precursor to Delta-9-tetrahydrocannabinol, which is the principal psychoactive constituent of the Cannabis plant. It is also a meroterpenoid, a member of resorcinols and a phytocannabinoid. It derives from an olivetolic acid. It is a conjugate acid of a cannabigerolate.
Δ-8-tetrahydrocannabinol is a psychoactive cannabinoid found in the Cannabis plant. It is an isomer of delta-9-tetrahydrocannabinol, the compound commonly known as THC, with which it co-occurs in hemp; natural quantities of ∆8-THC found in hemp are low. Psychoactive effects are similar to that of Δ9-THC, with central effects occurring by binding to cannabinoid receptors found in various regions of the brain.
Δ9-Tetrahydrocannabiorcol (Δ9-THCC, (C1)-Δ9-THC) is a phytocannabinoid found in Cannabis pollen. It is a homologue of THC and THCV with the alkyl side chain replaced by a smaller methyl group. Unlike THC and THCV, THCC has negligible affinity for the CB1 and CB2 cannabinoid receptors because of the smaller methyl group and does not have psychoactive effects as a result, but conversely it is significantly more potent than THC or THCV as an activator of the TRPA1 calcium channel which plays an important role in pain perception, and it has been shown to produce analgesic effects via activation of spinal TRPA1 channels. THCC was studied by Roger Adams as early as 1942.
Hexahydrocannabinol (HHC) is a hydrogenated derivative of tetrahydrocannabinol (THC). It is a naturally occurring phytocannabinoid that has rarely been identified as a trace component in Cannabis sativa, but can also be produced synthetically by firstly acid cyclization of cannabidiol and then hydrogenation of tetrahydrocannabinol. The synthesis and bioactivity of HHC was first reported in 1940 by Roger Adams.
Cannabicitran (CBTC) is a phytocannabinoid first isolated in 1974 as a trace component of Cannabis sativa. Structurally related compounds can be found in some other plants. It is not psychoactive, but was found to reduce intraocular pressure in tests on rabbits, which may reflect agonist activity at the NAGly receptor that is known to be a target of many structurally related cannabinoids.
Cannabinoids are compounds found in the cannabis plant or synthetic compounds that can interact with the endocannabinoid system. The most notable cannabinoid is the phytocannabinoid tetrahydrocannabinol (THC) (Delta-9-THC), the primary intoxicating compound in cannabis. Cannabidiol (CBD) is another major constituent of some cannabis plants. Conversion of CBD to THC can occur when CBD is heated to temperatures between 250–300 °C, potentially leading to its partial transformation into THC.
