After decades-long search, antibiotics could come from marijuana — study

The last new class of antibiotics was discovered more than 30 years ago — and that is a problem. Misuse and overuse of antibiotics over the years has left medicine with a desperate need for new drugs.

After years of searching, a new study suggests that a potential new treatment may have been under our noses the entire time

The need for these drugs is critical. In the United States alone, drug-resistant infections now kill more than 35,000 people every year. If new therapies are not found, scientists predicted the annual global death toll due to antimicrobial resistance could reach 10 million by 2050 – more than cancer.

As a result, scientists have begun looking for new drugs in the most unorthodox of places: from Komodo dragon blood to 4-million-year-old caves to 10 Downing Street. The search may finally be over.

A new study suggests that a potential solution may lie in cannabis. Researchers found that a cannabinoid called cannabigerol (CBG) was effective at controlling control methicillin-resistant Staphylococcus aureus (MRSA) infections in mice. MRSA, one of the most common hospital superbugs, was responsible for the death of an estimated 20,000 people in 2017.

The study was published this week in the journal ACS Infectious Diseases.

Medical marijuana

The cannabis plant contains over 400 different chemical compounds, including cannabinoids, as well as terpenoids, flavonoids, and alkaloids. CBG is one of the 120 cannabinoids in the cannabis plant, and is of the non-psychoactive variety – meaning it won’t get you high. The two most well-known and research cannabinoids are THC and CBD, the former being the infamous high-inducing component of marijuana.

The medicinal application of cannabis dates back millennia; as far back as 2,600 BC. It has long been known to hold antibacterial properties, but research testing its potential to create new antibiotics has only just begun. This new work builds on a study from 2019 found that CBD, cannabis’s “cure-all”, showed promise as a potential antibiotic.

In the new study, the researchers from McMaster University, in Canada, found that CBG stopped MRSA bacteria from forming biofilms, which can often develop on the skin and medical implants and which harbor the bug, ready to transmit it to a human host. It also broke up preformed biofilms.

CBG worked by targeting the cytoplasmic membrane of gram-positive bacteria. Surprisingly, the cannabinoid appears to work as well as vancomycin — often referred to as the drug of last resort, reserved for the most dangerous of infections.

The science is still in the early stages, and the compound's effectiveness has yet to be tested in humans.

“There is much work to do to explore the potential of the cannabinoids as antibiotics from the safety standpoint,” Eric Brown, a microbiologist who led the work, said in an interview with The Guardian following the study's publication.

Back on the frontlines of the antibiotic crisis, the situation remains critical — but these findings open the door to a potentially viable therapy at a time when it seems as if all the doors are locked.

Abstract: The spread of antimicrobial resistance continues to be a priority health concern worldwide, necessitating the exploration of alternative therapies. Cannabis sativa has long been known to contain antibacterial cannabinoids, but their potential to address antibiotic resistance has only been superficially investigated. Here, we show that cannabinoids exhibit antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), inhibit its ability to form biofilms, and eradicate preformed biofilms and stationary phase cells persistent to antibiotics. We show that the mechanism of action of cannabigerol is through targeting the cytoplasmic membrane of Gram-positive bacteria and demonstrate in vivo efficacy of cannabigerol in a murine systemic infection model caused by MRSA. We also show that cannabinoids are effective against Gram-negative organisms whose outer membrane is permeabilized, where cannabigerol acts on the inner membrane. Finally, we demonstrate that cannabinoids work in combination with polymyxin B against multidrug resistant Gram-negative pathogens, revealing the broad-spectrum therapeutic potential for cannabinoids.