“Antibiotics are used as the first line of treatment for bacterial infections. However, antibiotic resistance poses a significant threat to the future of antibiotics, resulting in increased medical costs, hospital stays, and mortality. New resistance mechanisms are emerging and spreading globally, impeding the success of antibiotics in treating common infectious diseases.

Recently, phytocannabinoids have been shown to possess antimicrobial activity on both Gram-negative and Gram-positive bacteria. The therapeutic use of phytocannabinoids presents a unique mechanism of action to overcome existing antibiotic resistance.

Future research must be carried out on phytocannabinoids as potential therapeutic agents used as novel treatments against resistant strains of microbes.”

https://pubmed.ncbi.nlm.nih.gov/36143430/

“Current antibiotic treatments have limited efficacy against multidrug-resistant bacteria, causing a significant challenge for prescribing physicians. A lack of effective therapies or new antibiotics requires the development of alternative antimicrobial therapies. Research has shown phytocannabinoids and CB2 agonists to exhibit antibiotic activity against a variety of Gram-positive and Gram-negative bacteria. Although their antimicrobial activity is limited in terms of Gram-negative bacteria, they offer therapeutic potential when administered as an adjunct treatment with an outer membrane perturbing molecule to facilitate the permeation of compounds that are effective on Gram-positive bacteria. Research has also shown synergy supporting the potential for combination therapy both in vivo and in vitro. Furthermore, CB2 agonists, such as β-caryophyllene, are widely used in industry as food additives and traditional medicine, and many are FDA approved and generally recognised as safe (GRAS), making them a good option for a novel therapeutic. The studies presented in this review suggest an attractive potential for cannabinoid-based antibacterial treatments.”

https://www.mdpi.com/2075-1729/12/9/1394/htm

“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.”

https://pubmed.ncbi.nlm.nih.gov/36009966/

“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.”

https://www.mdpi.com/2079-6382/11/8/1099/htm

“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.”

https://pubmed.ncbi.nlm.nih.gov/35440801/