McMaster researchers find cannabis has antibiotic potential

“We were motivated obviously by the excitement around cannabis for medical use,” said Brown, who is a biochemistry and biomedical professor at McMaster.  

Similar to the well-known cannabinoids CBD and THC, CBG is another compound produced by marijuana plants. 

“One of the obstacles for the use of cannabis or cannabinoids is the lack of evidence about what these things might be good for,” said Brown, adding that he reasoned the plant was producing the substances for a purpose, possibly to protect itself against bacteria. 

The Staphylococcus aureus bacterial strain is recognized as a leading cause of infections and a major perpetrator of illness and death on the World Health Organization’s list of “priority pathogens” released in 2017.  

“It’s one of the superbugs which is causing considerable problems with drug resistant infections in the clinic and in the community,” he said, noting that it can cause minor irritations like pimples or boils, but can also lead to respiratory or blood infections in severe cases. 

The strain has become increasingly resistant to antibiotics currently on the market, but Brown’s study, ‘Uncovering the Hidden Antibiotic Potential of Cannabis,’ highlights the possibility of alternative drug therapies.

Over a span of two years, Brown tested several different commercially available cannabis compounds in mice. He said his team worked in collaboration with Jakob Magolan, an associate professor of biochemistry and biomedical sciences at McMaster who produced synthetic CBG for the study.

Across several trials, CBG showed the strongest antibiotic potential, effectively targeting the resilient bacteria. The cannabinoid was able to penetrate the bacteria’s biofilm, a robust film-layer that the microorganism develops to protect itself, according to Brown. 

Other trials found that CBG in combination with the antibiotic polymyxin B, which can be used to treat pneumonia or urinary tract infections, could tackle the increasingly antibiotic-resistant gram-negative bacterial class. This bacteria differs in its structure and is common in wound or surgical site infections, pneumonia and meningitis.

Despite these findings, Brown said the cannabinoid is nowhere near ready to go on the market.  

In extremely high doses he found CBG actually damaged healthy human cells. Additionally, the substance was only tested against MRSA in mice, meaning it’s unclear if it would have the same results in humans. 

The complete study findings were published Feb.4 in the American Chemical Society Infectious Diseases journal.  

The next step, according to Brown, is to play around with the CBG compound and possibly combine it with another substance to reduce its toxicity. 

While the antibiotic potential of cannabis may be in the early stages, Brown is positive about where the field is headed. 

“I think all of the stigma is gone out of medical uses of cannabis or at least it’s waning and I think there’s growing interest in a budding technology community in Canada that gives me some hope that maybe this will go somewhere.”