There are over 100 different phytocannabinoids in the cannabis plant that interact with the body’s endocannabinoid system (ECS). The best known is the psychotropic tetrahydrocannabinol (THC), while cannabidiol (CBD) is the most common non-intoxicating cannabinoid. In addition, among the numerous phytocannabinoids, cannabichromene (CBC), cannabigerol (CBG) and cannabinol (CBN) have important therapeutic effects.
The chemical structure of tetrahydrocannabinol (THC) was deciphered in 1964. About 30 years later, researchers discovered the endocannabinoids N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol (2-AG) . These milestones led to the discovery of the endocannabinoid system (ECS), which has an important role in the regulation of physiological processes such as appetite, pain perception, mood and memory.
THC – Tetrahydrocannabinol
Tetrahydrocannabinol (THC), or more precisely delta-9-tetrahydrocannabinol, is primarily known for its psychotropic effect, which is mediated via CB1 receptors. The cannabinoid also has numerous medical effects. Indications with a good study record include, for example: Spasticity in multiple sclerosis, nausea and vomiting in cancer patients, neuropathic pain and loss of appetite in HIV and cancer patients. THC can also be effective in other diseases, for example Tourette’s syndrome .
When THC is combined with other cannabinoids, the effect can be enhanced: In a study by the University of London from 2017, THC and CBD in combination were shown to fight prepared human leukaemia cells more effectively than the individual substances. Leukaemia is cancer of the hematopoietic system . THC lowers intraocular pressure and could therefore be an anti-glaucoma agent .
CBD – Cannabidiol
Cannabidiol (CBD), the best-known cannabinoid after THC, does not trigger psychotropic effects and also has many positive medical effects. CBD binds only weakly on CB1- and CB2-receptors of the encocannabinoid system. On CB1-receptors CBD acts as negativ allosteric modulator, making it more difficult for THC to bind to the receptor. In this way the psychotropic effect are modulated by CBD . A finished drug containing CBD has already been approved for the treatment of rare forms of childhood epilepsy (Lennox-Gaustaut and Dravet syndromes), as well as seizures associated with tuberous sclerosis (TSC) .
Promising studies are also available for the treatment of anxiety and for antipsychotic effects in schizophrenia . CBD has antidepressant properties . Due to its antioxidant and anti-inflammatory effects, CBD can be helpful in diseases associated with oxidative stress, such as cancers, neurodegenerative diseases (e.g. Alzheimer’s disease) or metabolic diseases (e.g. diabetes mellitus) .
CBC – Cannabichromen
Cannabichromene (CBC) belongs to the non-psychotropic cannabinoids of the cannabis plant. Plants that produce a lot of CBD are bred by selective crossing. CBC acts on CB2 receptors, but not on CB1 receptors. It also affects TRP channels, which play a role in pain and inflammation. In studies on mice, CBC reduced pain and enhanced the analgesic effect of THC . CBC also shows antidepressant , antibacterial and antifungal properties . The anti-inflammatory effects of CBC were first described in 1980 in an animal model. CBC reduced the formation of oedema (water retention) in inflamed rat paws.
In experiments, CBC was also able to stabilise the cell membrane of red blood cells. The anti-inflammatory effect was compared with that of the non-steroidal anti-inflammatory drug phenylbutazone: At similar doses, CBC was more effective than phenylbutazone. In addition, CBC is better tolerated . In 2013, an Italian research team showed that CBC can have a positive effect on the viability of isolated mouse stem cells by interacting with adenosine A1 receptors .
CBG – Cannabigerol
Cannabigerol (CBG) is the precursor substance from which the cannabis plant forms the cannabinoids THC, CBD and CBC. The non-psychotropic cannabinoid is a so-called partial agonist at CB1 and CB2 receptors, i.e. it binds to the receptors, but exerts only a weak effect. Therefore, CBG reduces the psychotropic effects of THC . In addition, CBG also acts at alpha2-adrenoreceptors and 5-HT1A-receptors, a certain serotonin receptor. Research on CBG is still in its infancy, but recent studies show positive effects in various diseases. According to current studies, CBG can be effective in neurological diseases (e.g. Huntington’s disease, Parkinson’s disease, multiple sclerosis) and chronic inflammatory bowel diseases.
CBG has a blood pressure-lowering effect by binding to the alpha2-adrenoreceptor and could therefore be used in metabolic syndrome . It has also been shown that CBG can lower intraocular pressure, which makes the substance interesting for the treatment of glaucoma . CBG can also be effective in skin diseases such as psoriasis. CBG inhibits the pathologically increased formation of horn cells in psoriasis .
CBN – Cannabinol
Cannabinol (CBN) is an oxidation product of THC, i.e. it is formed by the influence of heat and oxygen and is mainly found in aged cannabis products. It was discovered as early as 1899 and is thus the first cannabinoid to be researched. Studies on humans have shown that CBN has a slightly psychotropic effect, which is intensified when combined with THC . Medically, CBN can be used due to its sedative and anticonvulsant (antispasmodic) effects. In addition, studies indicate anti-inflammatory and antibiotic effects, which could also combat multi-resistant germs such as MRSA (methicillin-resistant Staphylococcus aureus).
CBN could also be an option for external applications in the future. By inhibiting the formation of horny cells, CBN could be helpful in psoriasis. Since CBN also acts on heat sensors (TRPV2), the cannabinoid can potentially be used for the local therapy of burns . In 2019, a Canadian research team found in a study on rats that CBN alone or in combination can relieve chronic muscle pain, such as that experienced in fibromyalgia .
Researchers continue to work on gaining more knowledge about the effects of cannabinoids through scientific studies. Science will continue to answer questions about these and other phytocannabinoids in the coming years.
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