Some cannabinoids, substances found in cannabis, may be useful against Covid-19 by treating and suppressing the development of the severe form of the disease, two studies suggest.
The idea that these components could be useful in the treatment of the disease had already been discussed before because of their anti-inflammatory medicinal properties, explains Fabrício Pamplona, a cannabinoid pharmacologist and PhD in pharmacology from UFSC (Federal University of Santa Catarina).
However, the new research indicates that cannabinoids can be useful not only in the treatment when inflammation already affects the patient, but also to prevent the evolution of the disease to more severe conditions.
One of these studies, published as a preprint on the medRxiv platform and signed by researchers at the University of Waterloo, Canada, analyzed the effect of CBD (cannabidiol) on the ORF8 and ORF10 genes and on the M protein, all of the coronavirus.
Using cells in the laboratory, the scientists observed that CBD boosted an immune process called apoptosis — an immune response to a viral infection that serves to prevent the pathogen from replicating and, consequently, inhibit the spread of the virus.
It is this boost in apoptosis that would indicate the possibility of cannabidiol being used against Covid-19 at an early stage of the infection, since the invaded cells would not undergo the replication of the virus.
“The finding suggests that CBD may help limit an initial infection by promoting the removal of infected cells, thereby limiting spread,” the researchers state in the paper, which is yet to undergo peer review before eventual publication in an academic journal.
The study even compared the action of CBD on cells that lacked the genetic markers of the coronavirus. When analyzing this point, they noticed that cannabidiol did not boost the immune process, indicating that the substance encourages the response only in those cells that have suffered the infection.
Likewise, the scientists analyzed whether the three genetic markers of the coronavirus alone would already be a factor in stimulating apoptosis. If this were to happen, the action of CBD would not have a beneficial impact, as the body itself would develop the immune response upon contact with the virus.
However, the researchers write that this did not occur, as cells with the genetic markers only accelerated the apoptosis process when injected with CBD.
Pamplona states that “killing [por apoptose] only cells that are infected [é uma estratégia] very elegant from the point of view of pharmacology against this disease”.
Even so, the pharmacologist points out that the study was done in the laboratory and that further tests are needed to see if cannabidiol is really beneficial in delaying a more serious coronavirus infection.
Pamplona makes the same reservation for a second study on the topic that was published in the scientific journal Journal of Natural Products, carried out by researchers at Oregon State University (USA).
In this research, the scientists observed that cannabigerolic (CBGA) and cannabidiolic (CBDA) acids, substances found in Cannabis, acted against the binding of the S protein (or spike) of the coronavirus with human cells. In this way, the acids could prevent the virus from invading human cells.
To reach this conclusion, the study also took place in the laboratory. The researchers used pseudoviruses that expressed the Sars-CoV-2 spike protein. From there, it was noticed that the two acids had a preventive action against the invasion of these pseudoviruses in human cells in the laboratory.
Pamplona explains that this is not immunity per se “because immunity is an ability of the body to fight the virus, but in a certain way [essa descoberta] It would be a protection.”
“I mean, people become resistant — even if they had contact with the virus, it would not enter the cells. Therefore, it would not be able to infect or cause symptoms”, he comments.
The researchers point out that this action of acids was seen in the alpha and beta variants of the coronavirus. For the omicron, which has a large number of mutations in the S protein, there are no data.
Still on this study, Pamplona says that there is a certain degree of impediment because it was done with acids. According to him, cannabinoids can be found in two forms — neutral and acidic.
The neutral is the most common in the drugs already available in Brazil, while the acid ones are more similar to the natural form produced by the plant and, therefore, are also more difficult to be manipulated at an industrial level.
“There are products with acidic forms, but they are [mais recentes], at most in the last five years”, he explains. In addition, he says that “the effects of cannabinoids that we know are [normalmente os da] neutral form.
Thus, for Pamplona, the two studies suggest preventive mechanisms for more severe forms of Covid, but it is still too early to say whether they would, in fact, work in the human body.
“Both studies were carried out in cells, and there is a great distance between a phenomenon that happens in the cell and a phenomenon in the organism as a whole”, he reiterates. “It is not possible to guarantee that even these effects described [nos artigos] would take place in a normal infection in a human patient.”