There are over one hundred described cannabinoids in the Cannabis sativa plant, the most well known of which are THC and CBD. These are the two that get the most attention, and are being marketed to consumers. But in reality, scientists still do not know which cannabinoid, or what consortium of cannabinoids, is responsible for the observed medical and health benefits in humans. In addition to the cannabinoid CBDV that we reported on last week, another cannabinoid that is currently getting attention is CBN, or cannabinol. Preliminary reports have suggested that CBN may have beneficial properties, including antibacterial or antifungal effects and can aid in the treatment of cancers, psoriasis, glaucoma, arthritis, ALS, and other diseases. However, the science behind these claims is currently in the elementary stages, and many more studies are needed before the actual effects of CBN on human health can be elucidated and proven. In this article we will review some of the preliminary studies driving these claims in order to highlight some of the areas researchers are currently exploring to understand and find uses for CBN.
What is CBN?
CBN, or cannabinol, is not synthesized directly in the cannabis plant, but is actually a derivative of the cannabinoid THC. As THC ages, or is exposed to light and heat, it undergoes a chemical breakdown that leads to the formation of CBN. Although CBN is non-psychoactive, it may cause a drug test for THC to come back positive. This makes CBN quite complex, as researchers are still unsure to what degree it interacts with CB1 and CB2 receptors.
So, CBN does not exist in new weed, but only begins to appear when THC starts to breakdown. This means that cannabis which has been stored for longer periods of time will have higher levels of CBN. The chemical structure of CBN varies, and there are 7 different subtypes. Chemical analysis of CBN have found it to be an agonist of the body’s CB-2 receptors, and thus is likely to have immunosuppressive properties without any psychoactive effects, similar to CBD. However, some studies have claimed it may work synergistically with THC to increase the euphoric high and sedative effects from cannabis smoking, although this remains to be proven conclusively and no mechanistic explanation has yet been offered.
Health claims made for CBN
Increasingly, cannabis products are being made available that include CBN, in addition to THC or CBD, under the assumption that it has added benefits in the treatment of certain health conditions. One marker for the compound’s potential is the effort that researchers have been putting into synthesizing the molecule, which was achieved in 2019. Because we can now create pure forms of the molecule that can be used in studies, the science of CBN should start to take off quite rapidly. Today we are going to look at several potentiall areas of research that are being undertaken for CBN, and note where the research is today.
The most prominent claim for CBN from cannabis product retailers today is as a sleep aid. As we have discussed previously the effects of THC [ link to article from this week: Does THC improve sleep] and CBD on sleep, are still not fully understood. Claims have been made regarding the sleep-aiding properties of CBN for some time, and now it is included in edibles, patches, and transdermal gels specifically for that purpose. This is most likely based on the user hypothesis that Indica strains have a higher proportion of CBN (a theory which is largely unfounded). This theory was originally advanced by a 1973 study which concluded that CBN increased the effectiveness of THC in aiding in sleep. However, no subsequent studies have been done to collaborate this claim, and the original study was not well designed and has been largely questioned. But that has not stopped companies from making claims that CBN will help you get to sleep and stay asleep.
Antibacterial and Antifungal Effects
A 2009 study found that CBN had “moderate” antimicrobial activity in regards to the bacteria Mycobacterium intracellulare which causes tuberculosis. It also showed “good” Staphylococcus aureus activity (the cause of many upper respiratory and skin Staph infections). Lastly, it exhibited “good” antifungal activity against Candida albicans, a fungus that often affects cancer patients undergoing chemotherapy and those on immunosuppressive drugs for which few effective medications are currently available. At this time, no other studies have been completed to collaborate these claims.
A 1973 study looked at the anti-convulsant effects of cannabinoids in seizures induced in rats through electroshocks. It was found that THC, CBD, and CNB all had anticonvulsant effects in the rats, however the effects were more pronounced with THC and CBD then with CBN. Further studies have shown cannabis to be an effective treatment for some types of seizures, however no other studies are currently available on the role that CBN plays in regards to other cannabinoids in the plant, and most studies point to CBD as the stronger anti-convulsant.
Like THC and CBD, CBN has been described as an analgesic. In fact, it was mentioned in the patent applications for both the cannabis patch in 2000, and a new transdermal gel in 2018. A recent study using mice to test pain response in facial muscles found that CBD and CBN, or a combination of the two, were equally effective at decreasing muscle pain. However, at this point, unlike CBD or THC, the types of pain that CBN can effectively treat have yet to be understood.
More and more, the anti-cancer properties of CBN are being explored. In studies it has been indicated that it may assist in the cancer fighting abilities of chemotherapy drugs such as Ara-C. A 1975 study found that mice treated with CBN had reduced tumor size and increased survival time over control in the treatment of a type of tumor known as Lewis Lung Adenocarcinoma. More recently, CBN was shown to induce cell cycle arrest and apoptosis in glioblastoma, hepatocellular carcinoma and breast cancer cells, a study which still needs to be replicated in vivo. It may however be useful in the treatment of the symptoms associated with cancer treatment by acting as an appetite stimulant. A 2012 study in rats found that CBN “significantly” increased appetite and food consumption, while CBD reduced it, so in addition to actual cancer fighting properties, it may also aid in the symptoms of treatment, as with THC.
ALS, or Lou Gehrig’s Disease
ALS is a degenerative motor neuron disease for which there is usually no known cause, and currently no cure. A 2005 Study using mice found that CBN administered subcutaneously was effective in delaying the onset of disease. However, no decrease in overall mortality rates was observed. No human trials have yet been published, according to our research.
CBN has been thought to aid in decreasing interocular pressure in patients suffering from glaucoma, as was briefly mentioned in a 2007 review although no comprehensive studies have been undertaken.
CBD has been shown to reduce inflammation and pain associated with rheumatoid arthritis through interaction with the CB-2 Receptors in the peripheral nervous system. Similar action is suspected with CBN, and a 2016 review indicated that it has been shown to reduce symptoms of collagen-induced arthritis. However, no controlled clinical trials have been completed to confirm or refute this claim.
Negative Findings Regarding CBN
A study conducted in 1983 looked at the bronchodilatory effects of different cannabinoids abundant in the cannabis plant. Bronchodilators are helpful in the treatment of asthma and other respiratory issues. It was concluded that THC was an effective bronchodilator, however both CBD and CBN were not.
It has been claimed that cannabis consumption reduces testosterone levels in men, and in a 1976 study involving extracted mice testicles it was found that CBN decreased plasma testosterone levels. A follow-up study in 2019 found similar results when administering mice CBN for extended periods of time, while this has been shown in mouse models, this has still not been shown in humans.
Aging cannabis to Increase CBN?
Because CBN is the degradation product of THC, if cannabis flower is left in warm conditions the ratio of CBN to THC will increase. This has led to the theory that you can store, or ‘age’ cannabis in order to improve its effect as a sleep aid. It should be noted that these claims are unproven, and may be dangerous. Molds can grow on weed over time if not stored properly, and there is even one case study of a near fatal incident where a 17-year old buried his weed before smoking because he heard it would improve its quality.
The evidence for the medicinal and health benefits of the cannabis is growing rapidly, and controlled clinical trials involving THC and CBD are leading to more widespread acceptance in the scientific community. CBN appears to be the next cannabinoid that will be widely marketed to consumers, with several companies entering the market, including industry leaders such as Mary Medicinals and Medical Marijuana Inc.. Researchers are getting on board with CBN, and new studies are being completed to understand just how strong of a role this molecule plays in the medicinal and health effects realized with the Cannabis sativa plant.