A chemical found in live cannabis plants could help protect human cells against coronavirus infections, research suggests.
A study by scientists at Oregon State University (OSU) and Oregon Health and Science University found that two acids present in hemp, a type of cannabis plant used widely in cloth, paper and as a drug, were able to jam the gears of the virus that causes Covid-19.
The researchers said the two compounds can bind onto the SARS-Cov-2 virus' spike protein, which it uses to invade and commandeer human cells and which gives the coronavirus family its name.
However, the compounds probably cannot be consumed via any of the traditional methods of taking cannabis as a drug, meaning they would have to be harvested separately to make a specific medicine.
“These cannabinoid acids are abundant in hemp and in many hemp extracts,” said lead author Richard van Breemen of OSU's Global Hemp Innovation Center.
“They are not controlled substances like THC, the psychoactive ingredient in marijuana, and have a good safety profile in humans. And our research showed the hemp compounds were equally effective against variants of SARS-Cov-2."
The study, published in the peer-reviewed Journal of Natural Products on Monday, examined numerous plant extracts such as red clover, wild yam, hops and licorice for potential affinity with the Covid spike protein.
The spike protein is a microscopic structure protruding from the body of the virus, featuring chemical receptor sites that have evolved to bind onto the outer parts of human cells. If another chemical binds to those receptors, it can block them, making them useless.
The two compounds that worked best were cannabigerolic acid, known as CBG-A, and cannabidiolic acid, known as CBD-A, both precursors to the better-known chemicals in cannabis drugs.
The former exists only while the cannabis plant is growing, while the latter is converted into CBD, one of the key ingredients in recreational and medicinal cannabis, through burning, vaping or baking.
The chemicals worked well against both the alpha and beta variants of coronavirus, raising the prospect that they might also function against Omicron and other mutations.
"Our data show CBDA and CBGA are effective against the two variants we looked at, and we hope that trend will extend to other existing and future variants," said Mr van Breemen.