A Canadian study looked at whether cannabis extracts might play a role in connection with the coronavirus.
A research team from Canada examined extracts from at least 13 high-CBD varieties of Cannabis sativa in the lab. The researchers observed that some of these extracts changed the amount of the protein ACE2 in tissue cells. ACE2 is the protein the coronavirus SARS-CoV-2 uses to dock onto cells. What this means for humans, however, cannot be concluded from lab results like these.
Research into cannabis compounds in connection with viruses is nothing new. Ever since the outbreak of the SARS virus in 2002, studies have looked at individual terpenes that also occur in cannabis and examined their properties in the lab.
In the discussion forum for the Canadian publication, which had been online for about a month at the time, the results were hotly debated. One comment from the head of the study, Professor Igor Kovalchuk, is particularly interesting. Replying to a critical question, he said, in essence, that the team had never claimed CBD was responsible for reducing the ACE2 protein, because they simply did not know. It was true, though, that the effect was probably not due to CBD alone, and future research would include more varieties with a broader spectrum of cannabinoids.*
On the one hand, Professor Kovalchuk thus underlines how little research still knows about how the compounds in cannabis interact. Much remains to be investigated. On the other hand, he indirectly points to the so-called entourage effect. This hypothesis states that a mixture of plant compounds can have a different biological activity than an isolated pure substance. According to this idea, it would not be CBD alone that is responsible for the observed effects, but the interplay of the plant's own compounds such as CBD, THC, terpenes and flavonoids.
So does cannabis help against COVID-19? That cannot be concluded from this study. These are lab results from a preprint, and cannabis or CBD products are not a means of preventing or treating COVID-19.
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* Original comment by Igor Kovalchuk, 25 May 2020: «Thank you for your comments Amanda, I appreciate you took time to read the paper. Few things to get straight. We have never stated that CBD is being responsible for decreasing ACE2 protein, as we simply don't know it. What you are right about is that the effect is likely not due to CBD alone and yes, future research will include more lines, with broader spectrum of cannabinoids.»
Link to the study: «In Search of Preventative Strategies: Novel Anti-Inflammatory High-CBD Cannabis Sativa Extracts Modulate ACE2 Expression in COVID-19 Gateway Tissues»