01 NOV 2013
Contributing Author Claire Duplan
The search for potential medical applications for the compounds that are present in the marijuana or cannabis plant has included studies into the efficacy of various compounds for the treatment of a range of diseases, including cancer, multiple sclerosis, anxiety and depression. However, although advances have been made in strategies to limit the addictive effects of drugs like cannabis, the use of these compounds in medicine has been hampered by the potential for adverse effects.
Medical Research into Cannabis-Derived Compounds
Much of the research has involved isolating compounds found in the cannabis plant and testing their efficacy as medical treatments. Researchers isolated the primary active component of cannabis, tetrahydrocannabinol (THC) in 1964, but any potential medical applications of this compound must take into account its negative side effects, including its hallucinogenic and addictive properties. Addiction is a significant consideration for pharmaceutical drugs as well as illegal substances, since it can lead to serious additional health and social problems, as described by DrugAbuse.com. Researchers have therefore attempted to find non-addictive substances in the cannabis plant that might have similar medicinal effects, leading to the discovery of a cannabinoid that may help to treat multiple sclerosis (MS) just as effectively as THC, as well as to the recent research into the anti-cancer properties of cannabinoids.
Cannabinoids for Multiple Sclerosis Treatment
A study of cannabidiol (CBD), which is the second most plentiful cannabinoid in the marijuana plant, after THC, found that it could effectively reduce the type of inflammation associated with MS, without risking the same mind-altering side effects. The researchers treated mouse immune cells of the type that can attack and damage the brain and spinal cord, with either THC or CBD, and found that both chemicals reduced production of inflammatory molecules. The effect was particularly strong for the production of interleukin 17, a molecule that has been associated with the nerve cell damage that occurs in MS, a disease in which the immune system attacks the nervous system. Both THC and CBD appeared to prevent the immune cells from producing the inflammatory molecules that can harm the nerve cells, suggesting that they might be useful for the treatment of MS. The therapeutic potential of CBD is particularly exciting, since it does not carry the same risk of side effects as THC.
Cannabinoids for Cancer Treatment
A similarly important result was obtained in a study that looked at the potential for non-THC compounds from the marijuana plant to act against cancer cells. THC had previously been found to have significant anti-cancer properties, but as in the case of MS, the addictive and mind-altering qualities of the chemical had offset these benefits and raised concerns about its use in medicine. The new study examined the efficacy of a selection of other cannabis-derived compounds as anti-cancer agents.
The study was conducted by a group based at St George’s, University of London, which has previously undertaken research into the potential medical uses of cannabis-derived compounds. The current work explored the anti-cancer activity of six cannabinoid compounds. Two of these were different forms of cannabidiol, two were cannabigevarins, and two were cannabigerols. Together, these six compounds represent the most abundant forms of cannabinoids in the marijuana plant, other than the hallucinogenic THC. All of these cannabinoids lack the mind altering properties of THC, making them potentially more useful chemicals for medical treatment.
The researchers, led by Dr Wai Liu, tested the anti-cancer activity of these compounds against leukemia cells. Each of the six cannabinoids that was studied was found to be just as effective against cancer cells as THC, and when used in combination with one another, they were found to produce even greater effects. The cannabinoids were able to prevent the growth and development of the cancer cells, and even to kill them when applied in specific dosages.
Dr Liu believes that these cannabinoids show great promise as anti-cancer drugs, and are likely to produce minimal side effects, especially when compared to a compound like THC, which is known to have potential negative effects in addition to its anti-cancer properties. Cannabinoids can be produced easily and inexpensively, making them a potential source of new, lower cost cancer treatments. He describes this study as “a critical step in unpicking the mysteries of cannabis as a source of medicine”, a mystery that his research group will continue to explore in the future, particularly by testing the use of cannabinoids in combination with existing cancer treatments.