Amid the swirl of information or misinformation being aired and shared regarding the outbreak of the COVID-19 coronavirus pandemic has been discussion about whether cannabinoids — mostly CBD — has the capacity to kill the virus or stop its contagion.
Is there any truth to such claims? If not, what leads people to make or repeat them?
The short answer is that as of now, there is no cure, treatment, or vaccine for the COVID-19 disease from the coronavirus. Does that mean that cannabinoids are completely ineffective against the virus specifically, or against viruses in general? What about things like bacteria and fungus?
First things first: Cannabinoids have been found to be potent antimicrobials, meaning they work well against many types of bacteria and fungus, with the main “killer app” (pun intended) being the demonstration that cannabinoids can fight superbugs like MRSA and many common fungal infections including Candida. It is a well-known concept that goes back hundreds if not thousands of years and is recently supported by modern science and medicine. Second, cannabinoids do help certain types of viral infections. So, everything’s good, right?
Well, no. Unfortunately, a little knowledge is dangerous, and decades of prohibition of foundational investigative research on Cannabis and cannabinoids have bred some misleading assumptions, including some topics covered elsewhere:
- Is CBD an Anti-Viral for Coronavirus, SARS, MERS, and Influenza?
- Is CBD an Anti-Viral Agent for Coronavirus, Influenza, MERS, and SARS Plus Key Antiviral Supplements?
- FALSE: Cannabis ‘kills coronavirus’
Alas, bits and pieces of otherwise very valid cannabis science can be taken out of context and presented in ways that make people jump to conclusions or on bandwagons claiming that cannabinoids are able to cure every variety of illnesses, including the very unfortunate and scary Covid-19 disease. Conversely, relying on incomplete or bad information could potentially prove to be harmful or even lethal if followed as fact.
The truth is that cannabinoids and terpenes are potent small molecules that act by binding and signaling through the G-coupled master protein receptors (GCPR). The GCPR network includes hundreds of receptors that interact to modulate intracellular cascade signaling networks that are responsible for promoting cellular homeostasis or balance. Cannabinoids, terpenes, and hundreds of other phytochemicals interact through the network, triggering different interactions, via the second messenger (or cascade) system, which elicit responses from the pathways that control a number of different important functions in cells. One such function is a buzzword these days: Apoptosis (i.e., programmed cell death) is how our bodies turn over old cells, kill cancer cells, and use other cells such as macrophages and other killer cells to capture invading cells, viruses, or antigens and render them as non-harmful/nonpathogenic.
There are a host of second messenger systems (e.g., cAMP, AKT, AMPK, Mapk, NF-kappaB, notch, tgfB, etc.), each of which has many control proteins that then respond to trigger or affect other pathways/proteins to achieve the necessary outcome. One of these key pathways is tied to inflammation (of which we know CBD is extremely beneficial): as previously alluded to, apoptosis is involved in anything that is necessary to kill diseased cells, including microbial or virally infected cells. While providing a complete review of cannabinoids and second messenger signaling is beyond the scope of this brief article, suffice it to say that cannabinoids and the endocannabinoid system are like the proverbial “one ring to rule them all”: The endocannabinoid system, through cannabinoids (plant or endo), interact with every other system in the body via second messenger signaling to bring everything into balance.
So, if cannabinoids do work, what is the issue?
Part of the problem is that in some cases specific cannabinoids can in fact help against certain types of viruses, at least in vitro. Some studies have forwarded claims of efficacy in mice or monkeys. Unfortunately, no such studies have been allowed on humans, and the number of viruses studied were small and very specific to types of viruses that are not the novel coronavirus now causing casualties and concern. The viruses that have been studied include mouse hepatitis C (a betacorona virus), human and simian immunodeficiency virus (HIV or SIV), herpes simplex virus (HSV), and influenza viruses. The silver lining is that certain cannabinoids were in fact found able to inhibit the replication of a betacorona virus (MHV) in vitro, so that should motivate further investigation.
The issue remains that there just is not sufficient information. CBD helps with some viruses, but not all. CBD helps reduce inflammation. Some viruses need and cause systemic inflammation in the process of taking over the hosts and easing their transmission to the next set of cells for infection. For those viruses that need and cause inflammation, CBD may indeed help reduce the severity of infection. Is coronavirus a virus that causes or needs systemic inflammation? The answers are not yet clearly known.
Cannabinoids can also be immunosuppressive. Unfortunately, use of CBD or another cannabinoid which reduces inflammation against a virus that doesn’t need inflammation as a mode of host invasion causes a degree of immunosuppression in the host, ergo making any chances of beating the virus worse. That is a vital problem. So, without further study and understanding of the full route of infection, or more understanding of each and every pathway that cannabinoids trigger (including immunosuppression or inhibition of inflammation) — much less all the potential cross interactions — it is premature and potentially hazardous to assume that all cannabinoids will work the same way and achieve the desired effect, based on the premise that someone might have shown a connection in a petri plate or a monkey that a certain cannabinoid is effective against a certain type of virus.
CBD also has been shown to inhibit cytochrome P450 enzymes, which exist in the liver and are responsible for metabolizing up to 60% of currently prescribed pharmaceutical drugs. Combined with the fact that many people do not tell their medical practitioners about their use of cannabinoids, and adding pharmaceuticals that may be prescribed by doctors, the potential to have compounds working at odds with each other increases significantly.
Cannabis is an amazing plant, and it is highly likely that methods can be found to trigger the systems as intended, to achieve desired effects; it is also likely that potent antivirals can be found. Cannabis has potential for products effective against viruses, and the very short list of data presented here should be encouraging toward a call for increased cannabis/cannabinoid research on many different medical fronts. That is especially true in the U.S., whose researchers have been hamstrung by cruel restrictions against researching some of the most fascinating set of molecular assets to present themselves to modern medicine. Science just needs to keep looking for answers and follow the proper route toward new drug discovery and evaluation of new medicines.