The quest for new antibiotics has led researchers to a surprising candidate: the marijuana compound CBD.
A new study finds that CBD, or cannabidiol, is "remarkably effective" at killing bacteria, at least in a test tube, the researchers in the new study said. The results showed that CBD had antibiotic effects against a number of so-called Gram-positive bacteria, including types of staph and strep bacteria, as well as strains that had become resistant to other antibiotic drugs.
Still, the results are very preliminary, and people should absolutely not self-treat infections with CBD at this time, the researchers said.
"It needs a lot more work to show [that CBD] would be useful to treat infections in humans," said study lead author Mark Blaskovich, of The University of Queensland's Institute for Molecular Bioscience's Centre for Superbug Solutions in Brisbane, Australia. "It would be very dangerous to try to treat a serious infection with cannabidiol instead of one of the tried and tested antibiotics," Blaskovich told Live Science. [6 Superbugs to Watch Out For]
The study was conducted in collaboration with Botanix Pharmaceuticals Ltd., a drug-discovery company that's investigating uses of synthetic cannabidiol for a range of skin conditions. The company also helped fund the study.
The work will be presented today (June 23) in San Francisco at ASM Microbe, the annual meeting of the American Society for Microbiology; the research has not yet been published in a peer-reviewed journal.
CBD has garnered a lot of attention in recent years for its potential to provide therapeutic effects without producing the high typically associated with marijuana. But so far, the Food and Drug Administration (FDA) has approved CBD only in prescription-drug form for treating rare types of childhood epilepsy.
In addition, studies suggest that CBD may have anti-inflammatory effects, but whether it also has antibiotic effects has been unclear.
In the new study, the researchers tested whether a synthetically produced form of CBD could kill different types of bacteria.
In experiments in lab dishes, the synthetic CBD did just as well as the prescription antibiotics vancomycin and daptomycin in killing certain strains of Staphylococcus and Streptococcus bacteria. The compound even worked against strains of staph and strep bacteria that had become resistant to vancomycin and daptomycin, the authors said.
CBD also showed activity against bacterial biofilms, which form when bacteria secrete proteins to form films on surfaces. These biofilms can cause difficult-to-treat infections.
Experts cautioned that many different compounds appear to show antibiotic effects in lab dishes, known as "in vitro" experiments, but these findings don't always translate to people.
"Just because [CBD] has antibiotic activity in an in vitro assay doesn't mean it does in the human body," said Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security in Baltimore, who wasn't involved with the study. "Lots of different compounds … have [antibiotic] activity in a petri dish."
Many more studies will be needed to see if CBD could be used as an antibiotic in people. Research will need to determine the dose needed to kill bacteria in the body, whether this dose is safe and how the antibiotic might be delivered, Adalja said.
Still, Adalja said the research is promising. "[It's] more evidence that there [are] a lot of untapped avenues of research with CBD," he said.
The authors now plan to conduct animal studies to understand the types of infections CBD might treat, as well as how CBD may kill bacteria, Blaskovich said. In addition, Botanix plans to conduct a clinical trial in people to test whether CBD can effectively remove Staphylococcus aureus bacteria on the skin before surgeries, to prevent post-surgical infections, he said.
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Originally published on Live Science.
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Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.