The Antimicrobial Properties of Cannabis and Cannabis-Derived Compounds and Relevance to CB2-Targeted Neurodegenerative Therapeutics


“Cannabinoid receptor 2 (CB2) is of interest as a much-needed target for the treatment or prevention of several neurogenerative diseases. However, CB2 agonists, particularly phytocannabinoids, have been ascribed antimicrobial properties and are associated with the induction of microbiome compositional fluxes. When developing novel CB2 therapeutics, CB2 engagement and antimicrobial functions should both be considered. This review summarizes those cannabinoids and cannabis-informed molecules and preparations (CIMPs) that show promise as microbicidal agents, with a particular focus on the most recent developments. CIMP-microbe interactions and anti-microbial mechanisms are discussed, while the major knowledge gaps and barriers to translation are presented. Further research into CIMPs may proffer novel direct or adjunctive strategies to augment the currently available antimicrobial armory. The clinical promise of CIMPs as antimicrobials, however, remains unrealized. Nevertheless, the microbicidal effects ascribed to several CB2 receptor-agonists should be considered when designing therapeutic approaches for neurocognitive and other disorders, particularly in cases where such regimens are to be long-term. To this end, the potential development of CB2 agonists lacking antimicrobial properties is also discussed.”

Antibacterial, Antibiofilm, and Antioxidant Activity of 15 Different Plant-Based Natural Compounds in Comparison with Ciprofloxacin and Gentamicin


“Plant-based natural compounds (PBCs) are comparatively explored in this study to identify the most effective and safe antibacterial agent/s against six World Health Organization concern pathogens. Based on a contained systematic review, 11 of the most potent PBCs as antibacterial agents are included in this study. The antibacterial and antibiofilm efficacy of the included PBCs are compared with each other as well as common antibiotics (ciprofloxacin and gentamicin). The whole plants of two different strains of Cannabis sativa are extracted to compare the results with sourced ultrapure components. Out of 15 PBCs, tetrahydrocannabinol, cannabidiol, cinnamaldehyde, and carvacrol show promising antibacterial and antibiofilm efficacy. The most common antibacterial mechanisms are explored, and all of our selected PBCs utilize the same pathway for their antibacterial effects. They mostly target the bacterial cell membrane in the initial step rather than the other mechanisms. Reactive oxygen species production and targeting [Fe-S] centres in the respiratory enzymes are not found to be significant, which could be part of the explanation as to why they are not toxic to eukaryotic cells. Toxicity and antioxidant tests show that they are not only nontoxic but also have antioxidant properties in Caenorhabditis elegans as an animal model.”

“Some of the PBCs tested, including THC, CBD, cinnamaldehyde, and carvacrol, showed quite promising antibacterial and antibiofilm potency in comparison with common antibiotics (ciprofloxacin and gentamicin). They are not only non-toxic but also have antioxidant properties as well.”

Cannabis sativa CBD Extract Shows Promising Antibacterial Activity against Salmonella typhimurium and S. newington


“Products derived from Cannabis sativa L. have gained increased interest and popularity. As these products become common amongst the public, the health and potential therapeutic values associated with hemp have become a premier focus of research. While the psychoactive and medicinal properties of Cannabis products have been extensively highlighted in the literature, the antibacterial properties of cannabidiol (CBD) have not been explored in depth. This research serves to examine the antibacterial potential of CBD against Salmonella newington and Styphimurium. In this study, we observed bacterial response to CBD exposure through biological assays, bacterial kinetics, and fluorescence microscopy. Additionally, comparative studies between CBD and ampicillin were conducted against Styphimurium and Snewington to determine comparative efficacy. Furthermore, we observed potential resistance development of our Salmonella spp. against CBD treatment.”

Cannabidiolic acid in Hemp Seed Oil Table Spoon and Beyond


“Cannabidiolic acid (CBDA) is the main precannabinoid in industrial hemp. It represents a common constituent of hemp seed oil, but mainly abundant in the aerial parts of the plant (including their processing waste). Thus, the optimization of fast and low-cost purification strategies is mandatory, as well as a deep investigation on its nutraceutical and cosmeceutical properties. To this purpose, CBDA content in hemp seed oil is evaluated, and its recovery from wasted leaves is favorably achieved. The cytotoxicity screening towards HaCaT cells, by means of MTT, SRB and LDH release assays, suggested it was not able to decrease cell viability or perturb cell integrity up to 10 μM concentration. Thus, the ability of CBDA to differentially modulate the release of proinflammatory cytokines and chemokines mediators has been evaluated, finding that CBDA decreased IFN-γ, CXCL8, CXCL10, CCL2, CCL4 and CCL5, mostly in a dose-dependent manner, with 10 μM tested concentration exerting the highest activity. These data, together with those from assessing antimicrobial activity against Gram(+) and Gram(-) bacteria and the antibiofilm formation, suggest that CBDA is able to counteract the inflammatory response, also preventing bacteria colonization.”

Potential cannabidiol (CBD) repurposing as antibacterial and promising therapy of CBD plus polymyxin B (PB) against PB-resistant gram-negative bacilli

“This study aimed to assess the ultrapure cannabidiol (CBD) antibacterial activity and to investigate the antibacterial activity of the combination CBD + polymyxin B (PB) against Gram-negative (GN) bacteria, including PB-resistant Gram-negative bacilli (GNB). We used the standard broth microdilution method, checkerboard assay, and time-kill assay. CBD exhibited antibacterial activity against Gram-positive bacteria, lipooligosaccharide (LOS)-expressing GN diplococcus (GND) (Neisseria gonorrhoeae, Neisseria meningitidis, Moraxella catarrhalis), and Mycobacterium tuberculosis, but not against GNB. For most of the GNB studied, our results showed that low concentrations of PB (≤ 2 µg/mL) allow CBD (≤ 4 µg/mL) to exert antibacterial activity against GNB (e.g., Klebsiella pneumoniae, Escherichia coli, Acinetobacter baumannii), including PB-resistant GNB. CBD + PB also showed additive and/or synergistic effect against LOS-expressing GND. Time-kill assays results showed that the combination CBD + PB leads to a greater reduction in the number of colony forming units per milliliter compared to CBD and PB alone, at the same concentration used in combination, and the combination CBD + PB was synergistic for all four PB-resistant K. pneumoniae isolates evaluated. Our results show that CBD has translational potential and should be further explored as a repurposed antibacterial agent in clinical trials. The antibacterial efficacy of the combination CBD + PB against multidrug-resistant and extensively drug-resistant GNB, especially PB-resistant K. pneumoniae, is particularly promising.”

Anti-Microbial Activity of Phytocannabinoids and Endocannabinoids in the Light of Their Physiological and Pathophysiological Roles

“Antibiotic resistance has become an increasing challenge in the treatment of various infectious diseases, especially those associated with biofilm formation on biotic and abiotic materials. There is an urgent need for new treatment protocols that can also target biofilm-embedded bacteria. Many secondary metabolites of plants possess anti-bacterial activities, and especially the phytocannabinoids of the Cannabis sativa L. varieties have reached a renaissance and attracted much attention for their anti-microbial and anti-biofilm activities at concentrations below the cytotoxic threshold on normal mammalian cells. Accordingly, many synthetic cannabinoids have been designed with the intention to increase the specificity and selectivity of the compounds. The structurally unrelated endocannabinoids have also been found to have anti-microbial and anti-biofilm activities. Recent data suggest for a mutual communication between the endocannabinoid system and the gut microbiota. The present review focuses on the anti-microbial activities of phytocannabinoids and endocannabinoids integrated with some selected issues of their many physiological and pharmacological activities.”

Anti-Bacterial Properties of Cannabigerol Toward Streptococcus mutans

Frontiers in Microbiology: Multidrug Resistance in Pasteurellaceae“Streptococcus mutans (S. mutans) is a gram-positive facultatively anaerobic bacterium and the most common pathogen associated with tooth caries. The organism is acid tolerant and can undergo physiological adaptation to function effectively in acid environments such as carious dental plaque.

Some cannabinoids have been found to have potent anti-microbial activity against gram-positive bacteria. One of these is the non-psychoactive, minor phytocannabinoid Cannabigerol (CBG). Here we show that CBG exhibits anti-bacterial activities against S. mutans.

In summary, we present here data showing the mechanisms by which CBG exerts its anti-bacterial effect against S. mutans.”

“Cannabigerol (CBG) is a non-psychotropic Cannabis-derived cannabinoid (CB). In summary, the present study demonstrates an anti-bacterial effects of the Cannabis component CBG toward the cariogenic bacteria S. mutans. The interference of CBG with the caries causative S. mutans may provide a novel innovative way to combat dental caries.”

Chemical and Bioinformatics Analyses of the Anti-Leishmanial and Anti-Oxidant Activities of Hemp Essential Oil

biomolecules-logo“Industrial hemp is a multiuse crop that has been widely cultivated to produce fibers and nutrients. The capability of the essential oil (EO) from inflorescences as antimicrobial agent has been reported. However, literature data are still lacking about the hemp EO antiprotozoal efficacy in vivo.

The present study aims to unravel this concern through the evaluation of the efficacy of hemp EOs (2.5 mL/kg, intraperitoneally) of three different cultivars, namely Futura 75Carmagnola selezionata and Eletta campana, in mice intraperitoneally infected with Leishmania tropica. A detailed description of EO composition and targets-components analysis is reported.

Myrcene, α-pinene and E-caryophyllene were the main components of the EOs, as indicated by the gas-chromatographic analysis. However, a prominent position in the scenario of the theoretical interactions underlying the bio-pharmacological activity was also occupied by selina-3,7(11)-diene, which displayed affinities in the micromolar range (5.4-28.9) towards proliferator-activated receptor α, cannabinoid CB2 receptor and acetylcholinesterase. The content of this compound was higher in Futura 75 and Eletta campana, in accordance with their higher scavenging/reducing properties and efficacy against the tissue wound, induced by L. tropica.

Overall, the present study recommends hemp female inflorescences, as sources of biomolecules with potential pharmacological applications, especially towards infective diseases.”

Comparative Investigation of Composition, Antifungal, and Anti-Inflammatory Effects of the Essential Oil from Three Industrial Hemp Varieties from Italian Cultivation

antibiotics-logo“Industrial hemp is characterized by a huge amount of by-products, such as inflorescences, that may represent high-quality sources of biomolecules with pharmaceutical interest.

In the present study, we have evaluated the phytochemical profile, including terpene and terpenophenolic compounds, of the essential oils (EOs) of Futura 75Carmagnola selezionata and Eletta campana hemp varieties.

The EOs were also tested for antifungal properties toward Trichophyton mentagrophytes, Trichophyton rubrum, Arthroderma crocatum, Arthroderma quadrifidum, Arthroderma gypseum, Arthroderma curreyi, and Arthroderma insingulare. In parallel, we investigated the inhibitory effects of the EOs against tyrosinase, and the production of prostaglandin E2 in isolated mouse skin exposed to hydrogen peroxide.

In human H1299 lung adenocarcinoma cells, we also evaluated the influence of the EOs on the gene expression of angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2), which are involved in SARS-CoV-2 entry in human host. E-caryophyllene and α-pinene were the prominent terpenes in the EOs, whereas the cannabidiolic acid was the terpenophenol present at higher concentration.

The EOs inhibited the growth of all tested dermatophytes species. In isolated skin specimens, EOs prevented the hydrogen-peroxide-induced synthesis of prostaglandin E2, consistent with the intrinsic antityrosinase activity. Finally, in H1299 cells, all tested EOs reduced the gene expression of ACE-2 and TMPRSS2, as well.

Therefore, the present findings highlight the rationale for the use of the present EOs against infectious diseases.”

Industrial, CBD, and Wild Hemp: How Different Are Their Essential Oil Profile and Antimicrobial Activity?

molecules-logo“Hemp (Cannabis sativa L.) is currently one of the most controversial and promising crops. This study compared nine wild hemp (C. sativa spp. spontanea V.) accessions with 13 registered cultivars, eight breeding lines, and one cannabidiol (CBD) hemp strain belonging to C. sativa L.

The first three groups had similar main essential oil (EO) constituents, but in different concentrations; the CBD hemp had a different EO profile. The concentration of the four major constituents in the industrial hemp lines and wild hemp accessions varied as follows: β-caryophyllene 11-22% and 15.4-29.6%; α-humulene 4.4-7.6% and 5.3-11.9%; caryophyllene oxide 8.6-13.7% and 0.2-31.2%; and humulene epoxide 2, 2.3-5.6% and 1.2-9.5%, respectively.

The concentration of CBD in the EO of wild hemp varied from 6.9 to 52.4% of the total oil while CBD in the EO of the registered cultivars varied from 7.1 to 25%; CBD in the EO of the breeding lines and in the CBD strain varied from 6.4 to 25% and 7.4 to 8.8%, respectively. The concentrations of δ9-tetrahydrocannabinol (THC) in the EO of the three groups of hemp were significantly different, with the highest concentration being 3.5%.

The EO of wild hemp had greater antimicrobial activity compared with the EO of registered cultivars.

This is the first report to show that significant amounts of CBD could be accumulated in the EO of wild and registered cultivars of hemp following hydro-distillation. The amount of CBD in the EO can be greater than that in the EO of the USA strain used for commercial production of CBD. Furthermore, this is among the first reports that show greater antimicrobial activity of the EO of wild hemp vs. the EO of registered cultivars.

The results suggest that wild hemp may offer an excellent opportunity for future breeding and the selection of cultivars with a desirable composition of the EO and possibly CBD-rich EO production.”