Cannabis has had a long history of being used as medicine before it was added to the Canada’s Act to Prohibit the Improper Use of Opium and other Drugs in 1923. After the federal government legalized recreational use of this drug in 2017, the country’s researchers have found themselves in the privileged position of being able to learn much more about what its medical potential might be. Dr. Eric Brown, who holds the Canada Research Chair in Microbial Chemical Biology at McMaster University, is among those exploring this pharmaceutical frontier.
While cannabis is typically associated with psychotropic and sedative effects, a group of bioactive compounds known as cannabinoids do not display either of those properties. In fact, some yield antibacterial activity, which Brown and his colleagues have been studying in his lab at McMaster’s DeGroote Institute for Infectious Disease Research.
He has devoted much of his career to the challenge of bacteria that become immune to antibiotic compounds, which poses a serious threat to modern health care. In addition to increasing the patient recovery time, medical costs, and mortality rates, drug resistance highlights the fact that the most recent class of antibiotics was approved more than three decades ago.
“It’s a research area that has a tremendous amount of failure,” says Brown. “I think in part because there is this inherent need to create a chemical that has a toxicity to the bug but is tolerated by the host.”
He recently co-authored a paper outlining marijuana’s prospects for meeting that need. The findings have emerged from his ongoing fascination with the drug’s bioactive compounds and a desire to add scientific insights to the abundance of anecdotal evidence from bloggers and other cannabis users.
“Maybe these compounds are being made by the plant not necessarily to get the humans high but rather there’s a utility for the plant in terms of anti-bacterial and anti-fungal activities,” he hypothesizes.
Since cannabis compounds for testing can now be sourced commercially, Brown’s lab can study a range of cannabinoids that exhibit this antibacterial activity. One in particular, cannabigerol (CBG) showed the highest antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). The researchers found that CBG can eradicate the biofilm that forms around this bacterium and protects it from our body’s immune system. By inhibiting and killing the cells in this casing, CBG directly attacks the MRSA cell membrane, something most antibiotics do not do. Given the fundamental nature of the cell membrane structure, it will be much less likely that future generations of this bacterium will evolve an effective resistance to such medicine.
“We think it’s a drug discovery project right now,” says Brown, who is already envisioning the next steps. “We’d like to turn CBG into a lead, which has the right stuff to be a drug. We’re at a pre-clinical stage and we’re trying to do chemistry around the CBG scaffold to improve the compound.”
Meanwhile, Brown and his colleagues must obtain enough cannabinoids to do the job. Canada may be setting a regulatory standard as just the second country in the world to legalize recreational cannabis, but the process of releasing these products for science has been slow.
Currently, researchers require a granting license to work with the plant or with cannabis derivatives. The Brown Lab collaborated with the McMaster lab of synthetic chemist Jakob Magalon, which provided enough cannabinoids to carry out the research.
Brown emphasizes that these are among the growing pains that even the retailers experience.
“We’re well positioned in Canada to take advantage of any medical applications of cannabinoids that other countries cannot,” he concludes. “It is really exciting. There’s lot of work to do.”