Cannabis Compounds Successfully Stop Coronavirus In Test Tubes, Can Treat COVID-19?

JAKARTA - Early research showing a popular non-psychoactive compound derived from marijuana could help prevent or treat COVID-19 requires further investigation in rigorous clinical trials, researchers say.

Several recent laboratory studies on cannabidiol, or CBD, have shown promising results, attracting media attention.

However, many other promising potential COVID-19 treatments in test tubes, from hydroxychloroquine to various drugs used to treat cancer and other diseases, ultimately failed to show benefit for COVID-19 patients after being studied in clinical trials.

Marsha Rosner of the University of Chicago led the team that discovered CBD, apparently helping to curb SARS-CoV-2 in infected cells in laboratory experiments.

"Our findings don't say this will work in patients. Our findings make a strong case for clinical trials," he said.

Using small doses of highly purified CBD, which is close to what patients receive in an oral drug already approved for severe epilepsy, Rosner and colleagues found CBD did not prevent the coronavirus from infecting cells in test tubes.

Instead, it acts as soon as the virus enters the cell, blocking it from making copies of itself in part through its effects on the inflammatory protein interferon. They found a similar effect in infected mice, according to a report in 'Science Advances'.

When they looked at a group of adults with severe epilepsy, the researchers found that those taking the approved CBD drug had lower rates of COVID-19.

However, looking back on a small number of patients yields no conclusive information. Only randomized clinical trials can do that, Rosner said.

"I know my message is not something people want to hear," he said.

Meanwhile, small doses of tetrahydrocannabinol (THC), the cannabis ingredient that causes high cannabidiolic acid (CBDA), cannabidivarin (CBDV), cannabichromene (CBC) and cannabigerol (CBG) did not prevent the virus from leaving cells or preventing it from replicating, the research team found.

"Not only does THC not work, but combining it with CBD prevents CBD from working," explains Rosner.

A separate team recently reported in the 'Journal of Natural Products' that high doses of CBG and CBDA prevented the coronavirus from breaking into cells.

Richard van Breemen of Oregon State University told Reuters the dose his team tested was not toxic to cells. It's not yet clear whether the same high doses would be safe for humans, his team said.

"You want the lowest possible effective dose," says Rosner, because of the potential for side effects when the drug is filtered through the liver.

The CBD his team tested was more than 98 percent pure, while the purity in commercial products was much lower. "People should not run out and get CBD from their favorite pharmacy," he explained.

CBD products are widely available in many forms and have been touted, often without evidence from clinical trials, as a treatment for pain and other ailments.

Meanwhile, small trials of CBD in humans with COVID-19 are ongoing.

Separately, in one completed study, researchers in Brazil randomly assigned 105 patients with mild or moderate COVID-19 to receive either CBD or a placebo for 14 days along with standard care. CBD has no apparent effect, according to an October report in 'Cannabis and Cannabinoid Research'.

In an agreed-upon concept study at Sheba Medical Center, Israel, researchers randomly assigned patients with mild COVID to receive either CBD or a placebo.

An early-stage trial at Rabin Medical Center, also in Israel, aims to test the effects of CBD in seriously ill or critically ill patients. However, study leader Dr. Moshe Yeshurun ​​told Reuters the difficulty of gathering participants, due to the wave of the coronavirus being driven by the Omicron variant, is currently 'consisting mostly of patients with mild to moderate disease.'

Rosner's team is exploring the possibility of clinical trials that are likely to focus on asymptomatic or mild cases of COVID. Meanwhile, he fears media reports exaggerating the potential of cannabinoids will lead people to self-medicate with CBD, stop wearing masks and avoid vaccines.

"We would love to be able to say specifically, certain doses of cannabinoids are helpful, but at this point, vaccine-induced antibodies and antibody drugs are much more effective at blocking infection."