A 2011 study further explain that while CBD, CBG and CBC are all just moderate antifungal agents, these three cannabinoids may increase the power of caryophyllene oxide, a highly effective antifungal. According to the study, CBG and CBC both eradicated a common fungal infection in humans in 15 days. This is a comparable rate to many pharmaceutical antifungal drugs.
These results seem to, in part, back up a 1981 study in which CBC was tested as an antibacterial and antifungal on rats. The researchers concluded that CBC has strong antibacterial activity and mild to moderate antifungal properties.
In one study from 2008, researchers concluded that four major cannabinoids:
all show “potent activity” against bacteria like MRSA.
Cannabis’s Anti-Itch & Anti-inflammatory Properties Can Ease Vaginal Infection Symptoms
The biofilms formed by C. albicans in the absence or presence of CBD (6.25, 12.5, and 25 μg/mL) as described above were washed with PBS and resuspended in PBS to a final density of OD600 = 0.1. A total of 100 μL cell suspension was mixed with the same volume of BacTiter-Glo TM reagent (Promega, Madison, WI, USA) and incubated for 5 min at room temperature prior to reading the luminescence in the Infinite M200 PRO plate reader (Tecan). Data are presented as percentage of the untreated control. The assay was performed in triplicates.
In conclusion, we demonstrate here that CBD exhibits specific anti-biofilm activity against C. albicans without significantly affecting either planktonic fungal growth or viability. We propose that CBD exerts its anti-biofilm activity towards C. albicans biofilm through a multi-target mode of action, which differs from commonly used antimycotics. Thus, CBD should be explored for further development as an alternative treatment to combat fungal infections.
2.6. Determination of Minimal Fungicidal Concentration (MFC)
1 Biofilm Research Laboratory, Faculty of Dental Medicine, Institute of Dental Sciences, The Hebrew University of Jerusalem, Jerusalem 9112002, Israel; [email protected] (R.V.S.); [email protected] (D.S.)
Next, we wanted to study the effect of CBD on pre-formed biofilms. Biofilms were allowed to form by an overnight incubation, then washed and exposed to increasing concentrations of CBD. Pre-formed fungal biofilm was dose-dependently affected by CBD. Already at the low dose of 1.56 μg/mL, mature biofilm was decreased by 28% as compared to untreated control ( Figure 1 B). Increasing the CBD dose to 3.12 μg/mL further enhanced its anti-biofilm activity by disrupting biofilm by 44% ( Figure 1 B). Finally, the metabolic activity in mature biofilm dropped to 32–46% when treated with higher concentrations (6.25–100 μg/mL) of CBD ( Figure 1 B).
Higher magnification analysis of cell morphology and structure of calcofluor white (CFW)-stained biofilms revealed a dose-dependent reduction in chitin fluorescence staining intensity with increasing concentrations of CBD [ Figure 3 (Ab’–Ae’)]. The CBD-treated hyphae appeared with thinner cell wall and septa [ Figure 3 (Ab’–Ae’)] than the control fungi ( Figure 3 (Aa’)). A similar pattern of CBD activity was observed after calculating the total chitin synthesis ( Figure 4 B). At sub-MBIC90 of 12.5 and 25 μg/mL, CBD reduced chitin content by 37% and 53%, respectively, while CBD at a dose of 50 μg/mL was able to diminish total chitin composition in biofilm by 90% as compared to the untreated control ( Figure 3 B). Along with the reduction in chitin content, the morphology of the fungal cell was notably altered by CBD. While control fungi [ Figure 3 (Aa,a’)] represented uniform true hyphae with true septa (red arrows), CBD-treated fungi [ Figure 3 (Ab–e,b’–e’)] appeared as pseudohyphae characterized by long elliptic branched forms with constrictions at the septal junctions (white arrows). In addition, true hyphae in the untreated control displayed parallel-sided walls [ Figure 3 (Aa,Aa’)], whereas the width of each segment of the pseudohyphae in CBD-treated biofilms was uneven, being wider at the center than at the septum [ Figure 3 (Ab–Ae,Ab’–Ae’)].