There are many well-known medical benefits of CBD, and the antifungal benefits of CBD have been known since the early 1980s, although little research has been done since that time. CBD and two other phytocannabinoids (plant cannabinoids), cannabigerol (CBG) and cannabichromene (CBC), have demonstrated noteworthy antifungal properties along with well-known and highly potent antibacterial properties.
The evolutionary function of this trait has to do with protecting leaves and flowers of cannabis plants from bacterial or fungal infections. Consequently, cannabis and hemp (hemp is any cannabis plant or strain with less than 0.3% THC) crops are preferred by farmers and botanists for their lack of need for pesticides and other dangerous chemicals that can poison the soil.1,4
In addition to these cannabinoids, the terpene caryophyllene oxide is a common constituent of cannabis plants. Not only is this terpene the specific chemical that drug-sniffing dogs respond to in cannabis, but it also has the ability to inhibit fungal growth in both cannabis plants and humans.1,4
What are terpenes?
Terpenes refer to a class of compounds which are found in nearly every species of plant. They produce the vast majority of “smells” that humans are receptive to, and they also have many biological activities including reduction of inflammation, reduced sensitivity to pain, and reduced anxiety.
All of these properties are possible because terpenes and cannabinoids share a common biochemical precursor, and this gives all of them the ability to bind with different biological substances, including receptors and enzymes.1
How do antifungal medications work?
Fungal infections can range from annoying to deadly. While bacteria are prokaryotes with no nucleus, fungi are eukaryotes, with a DNA-containing nucleus, just like all plants and animals. This means that it’s more difficult to find ways to kill fungal cells that won’t also harm human cells.
Consequently, almost all antifungal medications on the pharmaceutical market work the same way.
Just like cholesterol is necessary for human health and cellular membranes (it acts like cement, giving the membrane integrity and flexibility), a similar compound called ergosterol serves the same function in fungal cells: maintaining the structure of the cell membrane.
Pharmaceutical antifungals work by inhibiting the production of ergosterol (necessary for microbes), but not cholesterol (necessary for humans). This prevents the cell membranes of fungi from forming properly, causing fungal death without harming the human host.5
Antifungal benefits of CBD and other cannabinoids
CBD is known by many as the medicinal part of the cannabis plant, but this is a serious oversimplification. Almost every cannabinoid including THC is a potent anti-inflammatory modulator, and many others share properties ranging from the ability to reduce cancer growth to the ability to increase brain growth.
One of the medically valuable properties of cannabis that is shared by other cannabinoids in addition to CBD is the antimicrobial factor that CBG and CBC represent. In addition, the terpene caryophyllene oxide is a potent antifungal agent as well as the cannabinoid 8-hydroxy cannabinol, a metabolite of THC.1, 2, 4
While CBD dosage has a mild antifungal effect, CBC and CBG are moderate antifungal agents and their activities are shown to be potentiated by caryophyllene oxide. In a clinical study, CBG and CBC both caused eradication of onychomycosis, a common fungal infection in humans, at rates comparable to cyclopiroxolamine and sulconazole, two common pharmaceutical antifungals. Furthermore, caryophyllene oxide by itself was equipotent at the inhibition of growth of several fungi as amphotericin, another antifungal medication.1, 2, 3, 4
While the exact mechanism of cannabinoid antifungal activity is not entirely understood, there are some similarities between the cannabinoids found to have antifungal properties and the pharmaceutical agents which they were compared to.
- Most cannabinoids have a hydroxyl group, consisting of one oxygen atom with a single hydrogen attached to it (O-H), that allow them to attract other oxygen-containing molecules. This antioxidant activity is possible because the OH group is highly reactive. It is presumed that it binds with and oxidizes enzymes in the ergosterol pathway in fungi, thus preventing the formation of ergosterol and killing the cell. 2, 4, 5, 6
In addition, CBD, CBC, and CBG all moderate the expression of genes that are involved in immunity and the metabolism of sterols, like cholesterol and ergosterol. Research is now focused on the differences between cholesterol and ergosterol, and how they can be exploited by certain mixtures of plant cannabinoids with broad-spectrum qualities (broad spectrum = including many active (cannabinoid) ingredients, not just CBD alone), for the purpose of killing fungi without harming human cells.
We already know that the chemicals have around the same efficacy as pharmaceutical drugs, now it’s just about fine-tuning the mixtures and spreading the word so that people are aware of the antifungal benefits of CBD, CBG, and CBC.
- Russo, E. B. (2011). Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects. British Journal of Pharmacology, 163(7), 1344–1364. http://doi.org/10.1111/j.1476-5381.2011.01238.x
- Radwan, M. M., ElSohly, M. A., Slade, D., Ahmed, S. A., Khan, I. A., & Ross, S. A. (2009). Biologically Active Cannabinoids from High-Potency Cannabis sativa. Journal of Natural Products, 72(5), 906–911. http://doi.org/10.1021/np900067k
- Ghannoum, M. A., & Rice, L. B. (1999). Antifungal Agents: Mode of Action, Mechanisms of Resistance, and Correlation of These Mechanisms with Bacterial Resistance. Clinical Microbiology Reviews, 12(4), 501–517.
- TURNER, C. E. and ELSOHLY, M. A. (1981), Biological Activity of Cannabichromene, its Homologs and Isomers. The Journal of Clinical Pharmacology, 21: 283S–291S. doi:10.1002/j.1552-4604.1981.tb02606.x
- Yang, D., Michel, L., Chaumont, JP. et al. Mycopathologia (2000) 148: 79. https://doi.org/10.1023/A:1007178924408
- “Cannabinoids—Advances in Research and Application: 2012 Edition.” Edited by Q. Ashton Acton, Google Books, Scholarly Editions, 2012, books.google.com/books?id=UhDNQVEevjwC&source=gbs_navlinks_s.