It’s worth noting that the study was conducted in collaboration with Botanix Pharmaceuticals, a biopharmaceutical company that produces CBD-based products.
Despite these limitations, the study goes to show how CBD is a largely unexplored realm for science. Although many of its more lofty claims have the potential to fall flat, there are undoubtedly some fascinating insights to uncover from this long-overlooked compound.
“The combination of inherent antimicrobial activity and potential to reduce damage caused by the inflammatory response to infections is particularly attractive.”
Needless to say, this doesn’t mean you should be treating your infections with CBD oil or any other cannabis-related product. These findings have so far only been tested on the tissues of mice and in a petri dish, so it’s still very early days for the research. Equally, the researchers have no real grasp of the mechanism of action. It also remains unseen whether these effects will actually be seen in humans. After all, honey has well-known antimicrobial properties , but it’s hardly recommended to use it like Bactine on a cut.
Presenting their findings at the annual meeting of the American Society for Microbiology, scientists from the University of Queensland suggest that their work shows how CBD could be used to develop new treatments against gram-positive bacterial infections and even superbugs that have become resistant to conventional antibiotics.
“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 quest for new antibiotics has led researchers to a surprising candidate: the marijuana compound CBD.
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.
Lone and Lone investigated and compared the protein yield and antimicrobial and antioxidant effects of C. sativa following both aqueous and acetone extraction . From 500 g samples, protein extraction from aqueous methodologies yielded 4.8 g of crude extract and 3.2 g from acetone. When compared with the aqueous extract, the acetone extract displayed fractionally superior bactericidal properties. A concentration-dependent response was observed against all strains, with V. cholera being marginally the most responsive bacteria, closely followed by P. aeruginosa. The fungal response was slightly more pronounced in C. albicans compared to C. neoforms. Additionally, this study found that C. sativa has antioxidant properties, thus widening its potential for clinical use.
An interesting application for C. sativa-derived compounds is to use them for water filtration and purification purposes. Nadir et al. immobilized a mixture of cannabinoids and terpenes onto a polyethersulfone hybrid membrane. Bacterial decline was observed for both Gram-positive and Gram-negative pathogens. For example, an 88% decrease bacterial load for S. aureus was measured for the hybrid membrane compared to 30% for the standard membrane. Similar results were reported for several other species, including for Pseudomonas aeruginosa and Escherichia coli. This study represents a cost-effective solution for water filtration and antibacterial purification . All these examples highlight the great potential of C. sativa and its antimicrobial properties for applications in food, agriculture and drug discovery.
Cannabis sativa is an herbaceous plant that belongs to the family Cannabinaceae . It has been used by humans for over 5,000 years for medicinal and recreational uses, firstly in Central and Northeast Asia and subsequently spreading worldwide . Cannabis, or marijuana, is undoubtedly one of the most widely used illicit drugs . It has a complex chemical composition that includes cannabinoids , which are a group of secondary metabolites, several of which are responsible for the psychotropic effects [10,11]. Metabolic fingerprinting of C. sativa unveiled more than 480 compounds, including many terpenes and approximately 180 cannabinoids . Their biosynthesis involves the alkylation of olivetolic acid with geranyl diphosphate, which is catalyzed via geranyl transferase . This reaction leads to the formation of cannabigerolic acid (CBGA, Figure 1 A), which is a precursor molecule for numerous other cannabinoids, such as Δ 9 -tetrahydrocannbinol (Δ 9 -THC), cannabidiol (CBD), cannabigerol (CBG), cannabinol (CBN) and cannabichromene (CBC) (see Figure 1 B–F) [14,15].
2. Antibacterial Effects of C. sativa Extracts
Novak and co-workers evaluated the essential oils of five different cultivars of C. sativa against a large panel of Gram-positive and Gram-negative pathogens. The most abundant compounds in each oil sample were α-pinene, myrcene, trans-β-ocimene, α-terpinolene, trans-caryophyllene and α-humulene. The antimicrobial activity was in general poor, with only modest activity against Acinetobacter calcoaceticus and Brevibacterium linens. No ∆ 9 -THC and very low levels of CBD and CBN were detected in all the essential oils, which suggests a role of these compounds in the antimicrobial activity of C. sativa . A later study evaluated the oil of the seeds from the whole plant, extracted by petroleum ether and methanol. It was found (via the cup–plate agar diffusion method) that each extract exhibited an antimicrobial effect against Gram-positive pathogens. This is consistent with the study by Van Klingeren et al. , although the cannabinoid content of the plant specimen was not characterized. No significant antifungal activity was observed. Intriguingly, minor activity against Gram-negative bacteria was also reported, albeit a modest effect (note that the petroleum ether extract was inactive against Pseudomonas aeruginosa) . Hot water and ethanol leaf extracts have also been shown to possess an inhibitory effect against Gram-negative pathogens .
The first reports detailing the antibacterial activity of cannabinoids date back to the 1950s [41,42]. These experiments were conducted before the phytochemistry of cannabis was well characterized, which means that the bactericidal effect of C. sativa could not be directly attributed to a specific constituent. This was achieved in 1976, where it was found that ∆ 9 -THC and CBD are bacteriostatic as well as bactericidal against a panel of Gram-positive pathogens (see below) . There has also been great interest in the antibacterial properties of the essential oils and various extracts from C. sativa, such as those derived from petroleum ether, methanol and hot water. Various methods for isolating C. sativa extracts have also been applied. Traditional techniques include cold-pressing and solvent extraction, however higher yielding technologies which generate superior products are now emerging . Pressurized liquid extraction circumvents the need for filtration, whereas ultrasonic-assisted extraction (UAE) methods use less solvent and have short processing times, with higher yields and equivalent quality. “Green” methods include microwave-assisted extraction and supercritical fluid extraction, however up-scaling is challenging for the latter process .
Chemical structures of the most common cannabinoids: (A) CBGA; (B) Δ9-THC, with the numbering convention included; (C) CBD, also numbered; (D) CBG; (E) CBN; and (F) CBC.
Recently, Iseppi and co-workers conducted an extensive phytochemical characterization of 17 hemp essential oils from different varieties. Seventy-one compounds were identified, with the terpenes β-myrcene, α-pinene, α-terpinolene, β-pinene, trans-ocimene and limonene being the most abundant. CBDV, CBC and CBD were also detected, but below 0.05% of the percentage area in each chromatogram. The minimum inhibitory concentration (MIC) values of each oil were determined against a panel of Gram-positive pathogens and were found to have moderate to good antimicrobial activity. To determine the source of the observed antibacterial effect, the afore-mentioned terpenes and CBD were also evaluated. In general, good to moderate activity was observed against Listeria monocytogenes and Enterococcus isolates, but slightly less so for Staphylococcus and Bacillus isolates. Therefore, the antimicrobial effect is likely to be due to synergism between several compounds that are present in the essential oils .