Cannabis Compounds Show Promise Against Dangerous Fungus

A particularly dangerous fungal pathogen has found an unexpected foe in what might be one of the most beneficial plants around.

Researchers examining the chemical characteristics of cannabis have discovered that it can eliminate one of the world’s most harmful fungal pathogens, at least under laboratory conditions.

Cryptococcus neoformans, the fungus responsible for illnesses like cryptococcosis and cryptococcal meningitis, seems to be susceptible to topical treatments using cannabidiol and cannabidivarin, which are active compounds in Cannabis sativa.

“When Cryptococcus neoformans invades the central nervous system, it can lead to life-threatening meningitis,” notes biologist Hue Dinh from Macquarie University in Australia. “The mortality rate is alarmingly high and treatment can be quite a challenge.”

Fungal pathogens greatly threaten human health, with about 300 species known to cause diseases of varying severity. As these fungi, along with bacteria, develop resistances to existing medications, there’s a constant need for new treatment approaches.

One way to tackle this issue is by exploring medications that are already approved for other human conditions. Dinh and her team focused on cannabis, isolating five compounds to test against C. neoformans and certain other pathogens.

In the lab, they isolated the fungus and applied the compounds. Both cannabidiol (CBD), which doesn’t produce psychoactive effects, and cannabidivarin (CBDV), which is psychoactive, effectively killed C. neoformans quickly, even outpacing current antifungal treatments. They also showed effectiveness against fungi that cause conditions like jock itch and athlete’s foot.

“Proteomics analysis found that the antifungal properties of CBD and CBDV were tied to destabilizing membranes, changes in ergosterol biosynthesis, disruptions in metabolic pathways, and selective involvement of proteins associated with mitochondria,” the researchers reported in their study.

However, showing that a substance can kill fungus in controlled lab conditions is one thing; assessing its effectiveness in living systems is another matter. To further investigate their findings, the scientists turned to Galleria mellonella, the greater wax moth.

The larvae of this moth possess an immune response that’s quite similar to mammals. They’re not only inexpensive to acquire but also have short lifespans and require minimal maintenance, making them superb models for studying infectious pathogens and the treatments against them.

In the experiment, the moth larvae were given small burn wounds and separated into different groups. One group served as a control with just the open wounds; the others were infected with C. neoformans and treated with various substances.

One group received CBD dissolved in dimethyl sulfide, while another group received just dimethyl sulfide. The last group was treated with Amphotericin B, a medication typically used for severe fungal infections in humans.

The findings were impressive. The survival rate of larvae treated with CBD was significantly better than those treated with dimethyl sulfide alone and even higher than that of the Amphotericin B group.

In fact, their survival was nearly on par with the control group — the larvae that weren’t infected with the fungus at all.

While treating infections that reach the lungs and brain can be more complex, these results indicate that topical application of cannabidiol could effectively treat various fungal skin infections.

“If we can show that these treatments work well for common infections,” Dinh suggests, “you might just use some CBD oil directly on your skin for relief.”

This research has been published in PLOS Neglected Tropical Diseases.