Lockdowns and social distancing have been the norm for over a year now, and we’ve all had just about enough of the coronavirus pandemic. In the search for an effective treatment against the virus, scientists have turned their attention to cannabis, hoping to find some answers in the plant’s potent anti-inflammatory and anti-microbial properties. While speculation about the efficacy of cannabis to protect against covid has been rife for some time, a group of researchers has now finally published a study indicating that certain high-CBD cultivars do indeed appear to prevent the virus from entering human cells.
How Cannabis Stops COVID
Since the early days of the pandemic, researchers have been seeking a way to prevent the virus from entering cells. In doing so, they have focussed the majority of their attention on a protein called angiotensin-converting enzyme 2, or ACE2, which is found on cell membranes acts as a kind of receptor onto which the virus binds in order gain entry to these cells.
In other words, ACE2 is a kind of cellular gateway, through which the coronavirus is able to infect human cells. Worryingly, ACE2 is highly expressed in lung tissue, as well as in the mucous of the oral and nasal cavities – all of which makes the human respiratory system highly susceptible to covid. Fortunately, however, cannabis may offer a solution.
Publishing their work in the journal Aging, the study authors describe how they created 800 high-CBD cannabis strains and tested them on models of human tissue that had been infected with covid. Using whole plant extracts, they found that a number of these cultivars caused ACE2 to become downregulated in oral, airway and intestinal tissue[i].
By reducing the expression of ACE2 in the cells of these tissues, high-CBD cannabis may therefore significantly inhibit the ability of covid to infect cells.
The Entourage Effect May Be Responsible
Of all the extracts used in the study, four were found to be the most effective at reducing ACE2 in human tissues. Each of these had a CBD:THC ratio of roughly 30:1, although one of the four had a ratio that was close to 40:1. More good news came when the researchers found that some of these high-CBD strains downregulated a second enzyme called TMPRSS2, which has also been found to assist covid as it enters a cell.
However, when the team then repeated the experiment using pure CBD, they found no such reductions in either ACE2 or TMPRSS2. Similarly, pure cannabigerol (CBG) was ineffective at curtailing the expression of these proteins.
This led the authors to conclude that only whole plant extracts are apt to bring about these effects, while isolated cannabinoids appear to be of little use.
“We may indeed be observing the entourage effect in action, and the effects of extracts on ACE2 expression may not necessarily be attributed to CBD,” write the researchers. “In the future, it would be important to identify the cannabinoids and terpenes responsible for these observed effects, although, based on the entourage effect, one could predict that whole flower extracts may be more potent than single compounds.”
To add weight to this claim, the team discovered that the down-regulation of ACE2 was directly correlated with total terpene levels in each of the extracts used in the study.
While all of this is very positive and highly exciting, it’s important to remember that the researchers did not investigate how different modes of cannabis administration might alter this effect, so it shouldn’t be assumed that smoking a joint can protect against covid.
[i] Wang B, Kovalchuk A, Li D, Rodriguez-Juarez R, Ilnytskyy Y, Kovalchuk I, Kovalchuk O. In search of preventive strategies: novel high-CBD Cannabis sativa extracts modulate ACE2 expression in COVID-19 gateway tissues. Aging. 2020;12(22):22425-44. – https://www.aging-us.com/article/202225/text