The antibiotic potential of CBD

Researchers from The University of Queensland’s (UQ) Institute for Molecular Bioscience and Botanix Pharmaceuticals have shown that synthetic cannabidiol — better known as CBD — can kill the bacteria responsible for gonorrhoea, meningitis and Legionnaires’ disease, in a breakthrough that could lead to the first new class of antibiotics for resistant bacteria in 60 years.

UQ Associate Professor Mark Blaskovich said CBD — the main non-psychoactive component of cannabis — can penetrate and kill a wide range of bacteria including Neisseria gonorrhoeae, which causes gonorrhoea. In Australia, gonorrhoea is the second most common sexually transmitted infection and there is no longer a single reliable antibiotic to treat it because the bacteria is particularly good at developing resistance.

“This is the first time CBD has been shown to kill some types of gram-negative bacteria,” Dr Blaskovich said. “These bacteria have an extra outer membrane, an additional line of defence that makes it harder for antibiotics to penetrate.”

The team’s study, published in the journal Communications Biology, also showed that CBD was widely effective against a much larger number of gram-positive bacteria than previously known, including antibiotic-resistant pathogens such as MRSA (methicillin-resistant Staphylococcus aureus) or ‘golden staph’. Dr Blaskovich said CBD was particularly good at breaking down biofilms — the slimy build-up of bacteria, such as dental plaque on the surface of teeth — which help bacteria such as MRSA survive antibiotic treatments.

Dr Blaskovich said his team at the Centre for Superbug Solutions mimicked a two-week patient treatment in laboratory models to see how fast the bacteria mutated to try to outwit CBD’s killing power. He said, “Cannabidiol showed a low tendency to cause resistance in bacteria even when we sped up potential development by increasing concentrations of the antibiotic during ‘treatment’.

“We think that cannabidiol kills bacteria by bursting their outer cell membranes, but we don’t know yet exactly how it does that, and need to do further research.”

Additionally, the team discovered that chemical analogues — created by slightly changing CBD’s molecular structure — were also active against the bacteria. Dr Blaskovich said this is “particularly exciting because there have been no new molecular classes of antibiotics for gram-negative infections discovered and approved since the 1960s, and we can now consider designing new analogues of CBD within improved properties”.

Vince Ippolito, President and Executive Chairman of Botanix, said the research showed vast potential for the use of synthetic CBDs as antimicrobials. “Our company is now primed to commercialise viable antimicrobial treatments which we hope will reach more patients in the near future,” he said. “This is a major breakthrough that the world needs now.”

Dr Blaskovich said collaborating with Botanix has sped up the research, with Botanix contributing formulation expertise that has led to the discovery that how CBD is delivered makes a huge difference in its effectiveness at killing bacteria. The collaboration has also enabled Botanix to progress a topical CBD formulation into clinical trials for decolonisation of MRSA before surgery.

“Those Phase 2a clinical results are expected early this year and we hope that this will pave the way forward for treatments for gonorrhoea, meningitis and Legionnaires’ disease,” Dr Blaskovich said.

“Now we have established that cannabidiol is effective against these gram-negative bacteria, we are looking at its mode of action, improving its activity and finding other similar molecules to open up the way for a new class of antibiotics.”

Image credit: ©stock.adobe.com/au/HQUALITY

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