Exploring the Antibacterial Potential of Semisynthetic Phytocannabinoid: Tetrahydrocannabidiol (THCBD) as a Potential Antibacterial Agent against Sensitive and Resistant Strains of Staphylococcus aureus

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“Antimicrobial resistance (AMR) is one of the most challenging problems and is responsible for millions of deaths every year. We therefore urgently require new chemical entities with novel mechanisms of action. Phytocannabinoids have been adequately reported for the antimicrobial effect but not seriously pursued because of either stringent regulatory issues or poor drug-like properties. In this regard, the current work demonstrated the antibacterial potential of tetrahydrocannabidiol (THCBD, 4), a semisynthetic phytocannabinoid, against Staphylococcus aureus, the second-most widespread bug recognized by the WHO. THCBD (4) was generated from cannabidiol and subjected to extensive antibacterial screening. In in vitro studies, THCBD (4) demonstrated a potent MIC of 0.25 μg/mL against Gram-positive bacteria, S. aureus ATCC-29213. It is interesting to note that THCBD (4) has demonstrated strong effectiveness against efflux pump-overexpressing (SA-1199B, SA-K2191, SA-K2192, and Mupr-1) and multidrug-resistant (MRSA-15187) S. aureus strains. THCBD (4) has also shown a good effect in kill kinetic assays against ATCC-29213 and MRSA-15187. In the checkerboard assay, THCBD (4) has shown additive/indifference effects with several well-known clinically used antibiotics, tetracycline, mupirocin, penicillin G, and ciprofloxacin. THCBD (4) also exhibited good permeability in the artificial skin model. Most importantly, THCBD (4) has significantly reduced CFU in mice’s in vivo skin infection models and also demonstrated decent plasma exposure with 16-17% oral bioavailability. Acute dermal toxicity of THCBD (4) suggests no marked treatment-related impact on gross pathophysiology. This attractive in vitro and in vivo profile of plant-based compounds opens a new direction for new-generation antibiotics and warrants further detailed investigation.”

https://pubmed.ncbi.nlm.nih.gov/38051636/

https://pubs.acs.org/doi/10.1021/acsinfecdis.3c00154

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Graphene quantum dots based on cannabis seeds for efficient wound healing in a mouse incisional wound model: Link with stress and neurobehavioral effect

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“Graphene quantum dots (GQDs) are promising biomaterials with potential applicability in several areas due to their many useful and unique features. Among different applications, GQDs are photodynamic therapy agents that generate single oxygen and improve antimicrobial activity. In the present study, and for the first time, GQD were isolated from the Cannabis sativa L. seeds to generate C-GQD as a new biomaterial for antibacterial and wound healing applications. Detailed characterization was performed using FTIR, UV-vis, Raman spectra, photoluminescence, TEM examination, HRTEM, ζ-potential, and XRD. Our results revealed in vitro and in vivo antibacterial activity of C-GQDs against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) with reduced minimal inhibitory concentration (MIC) of 236µg/mL for both strains. In addition, the C-GQDs confirmed the in vitro analysis and exhibited anti-inflammatory activity by reducing the level of neutrophils in blood and skin tissue. C-GQDs act by accelerating re-epithelization and granulation tissue formation. In addition, C-GQDs restored neurobehavioral alteration induced by incisional wounds by reducing oxidative stress, decreasing cortisol levels, increasing anxiolytic-like effect, and increasing vertical locomotor activity. The wound-healing effects of C-GQDs support its role as a potential therapeutic agent for diverse skin injuries.”

https://pubmed.ncbi.nlm.nih.gov/38042382/

“In the present work, Cannabis sativa L. seeds GQDs (termed here as C-GQDs) were generated through a novel eco-friendly approach using cannabis seeds as precursor and without the addition of strong oxidants, thus avoiding the production of toxic gases.

Cannabis seeds offer an opportunity in regard to versatility, cost, and availability. They are a rich source of fiber and have significant medicinal value. They contain antibacterial cannabinoids with the potential to kill antibiotic-resistant bacteria. They also possess analgesics and anti-inflammatory effects that can be used in various biomedical applications.

More importantly, we found that C-GQDs accelerate the healing process by killing S. aureus and E. coli implicated in skin wound infection.

The C-GQDs, via their antibacterial, anti-inflammatory, anti-stress, anxiolytic-like effects showed an accelerative potential of wound closure in mice models of incisional wounds.”

https://www.sciencedirect.com/science/article/abs/pii/S0378517323010803?via%3Dihub

Aqueous Extracts from Hemp Seeds as a New Weapon against Staphylococcus epidermidis Biofilms

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“This study investigated the antibiofilm activity of water-soluble extracts obtained under different pH conditions from Cannabis sativa seeds and from previously defatted seeds. The chemical composition of the extracts, determined through GC-MS and NMR, revealed complex mixtures of fatty acids, monosaccharides, amino acids and glycerol in ratios depending on extraction pH. In particular, the extract obtained at pH 7 from defatted seeds (Ex7d) contained a larger variety of sugars compared to the others. Saturated and unsaturated fatty acids were found in all of the analysed extracts, but linoleic acid (C18:2) was detected only in the extracts obtained at pH 7 and pH 10. The extracts did not show cytotoxicity to HaCaT cells and significantly inhibited the formation of Staphylococcus epidermidis biofilms. The exception was the extract obtained at pH 10, which appeared to be less active. Ex7d showed the highest antibiofilm activity, i.e., around 90%. Ex7d was further fractionated by HPLC, and the antibiofilm activity of all fractions was evaluated. The 2D-NMR analysis highlighted that the most active fraction was largely composed of glycerolipids. This evidence suggested that these molecules are probably responsible for the observed antibiofilm effect but does not exclude a possible synergistic contribution by the other components.”

https://pubmed.ncbi.nlm.nih.gov/38003214/

https://www.mdpi.com/1422-0067/24/22/16026

Proteomic Changes in Methicillin-Resistant Staphylococcus aureus Exposed to Cannabinoids

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“Methicillin-resistant Staphylococcus aureus (MRSA) is a major human pathogen that causes a wide range of infections. Its resistance to β-lactam antibiotics complicates treatment due to the limited number of antibiotics with activity against MRSA. To investigate development of alternative therapeutics, the mechanisms that mediate antibiotic resistance in MRSA need to be fully understood. In this study, MRSA cells were subjected to antibiotic stress from methicillin in combination with three cannabinoid compounds and analyzed using proteomics to assess the changes in physiology. Subjecting MRSA to nonlethal levels of methicillin resulted in an increased production of penicillin-binding protein 2 (PBP2). Exposure to cannabinoids showed antibiotic activity against MRSA, and differential proteomics revealed reduced levels of proteins involved in the energy production as well as PBP2 when used in combination with methicillin.”

https://pubmed.ncbi.nlm.nih.gov/37411021/

https://pubs.acs.org/doi/10.1021/acs.jnatprod.3c00064

Antifungal and antibacterial activities of Cannabis sativa L. resins

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“Ethnopharmacological relevance: Cannabis sativa L. (Cannabaceae) is a plant native to Eastern Asia spread throughout the world because of its medicinal properties. Despite being used for thousands of years as a palliative therapeutic agent for many pathologies, in many countries research on its effects and properties could only be carried out in recent years, after its legalization.

Aims of the study: Increasing resistance to traditional antimicrobial agents demands finding new strategies to fight against microbial infections in medical therapy and agricultural activities. Upon legalization in many countries, Cannabis sativa is gaining attention as a new source of active components, and the evidence for new applications of these compounds is constantly increasing.

Methods: Extracts from five different varieties ofCannabis sativa were performed and their cannabinoids and terpenes profiles were determined by liquid and gas chromatography. Antimicrobial and antifungal activities against Gram (+) and Gram (-) bacteria, yeast and phytopathogen fungus were measured. To analyze a possible action mechanism, cell viability of bacteria and yeast was assessed by propidium iodide stain.

Results: Cannabis varieties were grouped into chemotype I and II as a consequence of their cannabidiol (CBD) or tetrahydrocannabinol (THC) content. The terpenes profile was different in quantity and quality among varieties, with (-)b-pinene, b-myrcene, p-cymene and b-caryophyllene being present in all plants. All cannabis varieties were effective to different degree against Gram (+) and Gram (-) bacteria as well as on spore germination and vegetative development of phytopathogenic fungi. These effects were not correlated to the content of major cannabinoids such as CBD or THC, but with the presence of a complex terpenes profile. The effectiveness of the extracts allowed to reduce the necessary doses of a widely used commercial antifungal to prevent the development of fungal spores.

Conclusion: All the extracts of the analysed cannabis varieties showed antibacterial and antifungal activities. In addition, plants belonging to the same chemotype showed different antimicrobial activity, demonstrating that the classification of cannabis strains based solely on THC and CBD content is not sufficient to justify their biological activities and that other compounds present in the extracts are involved in their action against pathogens. Cannabis extracts act in synergy with chemical fungicides, allowing to reduce its doses.”

https://pubmed.ncbi.nlm.nih.gov/37400009/

https://www.sciencedirect.com/science/article/abs/pii/S0378874123007079?via%3Dihub

Cannabidiol reduces LPS-induced nociception via endocannabinoid system activation

“Bacterial infections are often accompanied by fever and generalized muscle pain. However, the treatment of pain with an infectious etiology has been overlooked. Thus, we investigated the impact of cannabidiol (CBD) in bacterial lipopolysaccharide (LPS)-induced nociception.

Male Swiss mice received intrathecal (i.t.) LPS injection, and the nociceptive threshold was measured by the von Frey filaments test. Spinal involvement of the cannabinoid CB2 receptor, toll-like receptor 4 (TLR4), microglia and astrocytes were evaluated by i.t. administration of their respectively antagonists or inhibitors. Western blot, immunofluorescence, ELISA and liquid chromatography-mass spectrometry were used to assess Cannabinoid CB2 receptors and TLR4 spinal expression, proinflammatory cytokines and endocannabinoid levels. CBD was administered intraperitoneally at 10 mg/kg.

The pharmacological assay demonstrated TLR4 participation in LPS-induced nociception. In addition, spinal TLR4 expression and proinflammatory cytokine levels were increased in this process.

CBD treatment prevented LPS-induced nociception and TLR4 expression.

AM630 reversed antinociception and reduced CBD-induced endocannabinoids upregulation. Increased spinal expression of the cannabinoid CB2 receptor was also found in animals receiving LPS, which was accompanied by reduced TLR4 expression in CBD-treated mice.

Taken together, our findings indicated that CBD is a potential treatment strategy to control LPS-induced pain by attenuating TLR4 activation via the endocannabinoid system.”

https://pubmed.ncbi.nlm.nih.gov/37076976/

https://onlinelibrary.wiley.com/doi/10.1111/bcpt.13876

Cannabidiol and Cannabigerol Exert Antimicrobial Activity without Compromising Skin Microbiota

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“Cannabidiol (CBD) and cannabigerol (CBG) are two pharmacologically active phytocannabinoids of Cannabis sativa L. Their antimicrobial activity needs further elucidation, particularly for CBG, as reports on this cannabinoid are scarce. We investigated CBD and CBG’s antimicrobial potential, including their ability to inhibit the formation and cause the removal of biofilms.

Our results demonstrate that both molecules present activity against planktonic bacteria and biofilms, with both cannabinoids removing mature biofilms at concentrations below the determined minimum inhibitory concentrations. We report for the first time minimum inhibitory and lethal concentrations for Pseudomonas aeruginosa and Escherichia coli (ranging from 400 to 3180 µM), as well as the ability of cannabinoids to inhibit Staphylococci adhesion to keratinocytes, with CBG demonstrating higher activity than CBD. The value of these molecules as preservative ingredients for cosmetics was also assayed, with CBG meeting the USP 51 challenge test criteria for antimicrobial effectiveness. Further, the exact formulation showed no negative impact on skin microbiota.

Our results suggest that phytocannabinoids can be promising topical antimicrobial agents when searching for novel therapeutic candidates for different skin conditions. Additional research is needed to clarify phytocannabinoids’ mechanisms of action, aiming to develop practical applications in dermatological use.”

https://pubmed.ncbi.nlm.nih.gov/36768709/

“This report compares CBD and CBG’s antimicrobial effectiveness and further cements phytocannabinoids’ potential to be used as antimicrobial agents. Both molecules’ antimicrobial capacity strongly depends on the target microorganism, namely whether it is Gram-negative or Gram-positive. Nonetheless, we were able to determine MICs for all tested strains, including S. pyogenesE. coli, and P. aeruginosa. It is of note that CBG revealed a stronger antimicrobial effect than CBD, particularly in the challenge test and in the antibiofilm assay. Further studies are needed to understand these discrepancies, as they may be connected to structural differences, receptor-binding affinity, or another mechanism other than a receptor-mediated one. Since no significant impact on the skin microbiota was observed and given its current widespread use, both CBD and CBG might be considered safe. Thus, we can assume that the development of topical formulations with active concentrations of CBG and/or CBD might represent a promising approach to tackle skin conditions where microorganisms and inflammation play a fundamental role, including psoriasis, atopic dermatitis, and acne.”

https://www.mdpi.com/1422-0067/24/3/2389

Cannabis sativa CBD Extract Exhibits Synergy with Broad-Spectrum Antibiotics against Salmonella enterica subsp. Enterica serovar typhimurium

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“New generation antibiotics are needed to combat the development of resistance to antimicrobials. One of the most promising new classes of antibiotics is cannabidiol (CBD). It is a non-toxic and low-resistance chemical that can be used to treat bacterial infections.

The antibacterial activity of Cannabis sativa L. byproducts, specifically CBD, has been of growing interest in the field of novel therapeutics. As research continues to define and characterize the antibacterial activity that CBD possesses against a wide variety of bacterial species, it is important to examine potential interactions between CBD and common therapeutics such as broad-spectrum antibiotics.

In this study it is demonstrated that CBD-antibiotic (combination of CBD and antibiotic) co-therapy can effectively fight Salmonella typhimurium (S. typhimurium) via membrane integrity disruption. This research serves to examine the potential synergy between CBD and three broad-spectrum antibiotics (ampicillin, kanamycin, and polymyxin B) for potential CBD-antibiotic co-therapy. In this study, it is revealed that S. typhimurium growth is inhibited at very low dosages of CBD-antibiotic.

This interesting finding demonstrates that CBD and CBD-antibiotic co-therapies are viable novel alternatives to combating S. typhimurium.”

https://pubmed.ncbi.nlm.nih.gov/36557613/

“The decrease in antibiotic development over the 21st century has exacerbated the need for new antibacterial agents as well as new methodologies designed to retain the efficacy of current antibiotics. CBD extract from C. sativa has been presented as a promising antibacterial agent with in vitro efficacy against several relevant bacterial pathogens including Staphylococcus aureusStreptococcus pneumoniaeSalmonella spp. Clostridium difficileNeisseria spp., Moraxella catarrhalis, and Legionella pneumophila. This antibacterial activity achieved through membrane disruption of both Gram-positive and Gram-negative bacterial species presents CBD as a unique and particularly effective class of antibacterial agents.”

https://www.mdpi.com/2076-2607/10/12/2360

Anti-Bacterial Effect of Cannabidiol against the Cariogenic Streptococcus mutans Bacterium: An In Vitro Study

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“Dental caries is caused by biofilm-forming acidogenic bacteria, especially Streptococcus mutans, and is still one of the most prevalent human bacterial diseases. The potential use of cannabidiol (CBD) in anti-bacterial therapies has recently emerged.

Here we have studied the anti-bacterial and anti-biofilm activity of CBD against S. mutans. We measured minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC). The bacterial growth and changes in pH values were measured in a kinetic study. The biofilm biomass was assessed by Crystal Violet staining and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) metabolic assay. Spinning Disk Confocal Microscopy (SDCM) was used to assess biofilm structure, bacterial viability and extracellular polysaccharide (EPS) production.

CBD inhibited S. mutans planktonic growth and biofilm formation in a dose-dependent manner, with similar MIC and MBIC values (5 µg/mL). CBD prevented the bacteria-mediated reduction in pH values that correlated with bacterial growth inhibition. SDCM showed a decrease of 50-fold in live bacteria and EPS production. CBD significantly reduced the viability of preformed biofilms at 7.5 µg/mL with an 80 ± 3.1% reduction of metabolic activity. At concentrations above 20 µg/mL, there was almost no bacterial recovery in the CBD-treated preformed biofilms even 48 h after drug withdrawal.

Notably, precoating of the culture plate surfaces with CBD prior to incubation with bacteria inhibited biofilm development. Additionally, CBD was found to induce membrane hyperpolarization in S. mutans. Thus, CBD affects multiple processes in S. mutans including its cariogenic properties.

In conclusion, we show that CBD has a strong inhibitory effect against cariogenic bacteria, suggesting that it is a potential drug adjuvant for reducing oral pathogenic bacterial load as well as protecting against dental caries.”

https://pubmed.ncbi.nlm.nih.gov/36555519/

“We have shown that the mode of action of CBD against S. mutans is multifactorial and attributed to: inhibition of bacterial growth and subsequently hindrance of biofilm formation, diminished biofilm metabolic activity and prevention of bacterial recovery within the biofilms following CBD treatment. Some of these effects can be attributed to the membrane hyperpolarization caused by CBD. The combined anti-bacterial and anti-metabolic effects of CBD contribute to the prevention in pH drop with implications for being a potential adjuvant drug in protecting against dental caries.”

https://www.mdpi.com/1422-0067/23/24/15878

Antimicrobial and Cytotoxic Effects of Cannabinoids: An Updated Review with Future Perspectives and Current Challenges

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“The development of new antibiotics is urgently needed to combat the threat of bacterial resistance. New classes of compounds that have novel properties are urgently needed for the development of effective antimicrobial agents.

The extract of Cannabis sativa L. has been used to treat multiple ailments since ancient times. Its bioactivity is largely attributed to the cannabinoids found in its plant. Researchers are currently searching for new anti-infective agents that can treat various infections. Although its phytocannabinoid ingredients have a wide range of medical benefits beyond the treatment of infections, they are primarily associated to psychotropic effects.

Different cannabinoids have been demonstrated to be helpful against harmful bacteria, including Gram-positive bacteria. Moreover, combination therapy involving the use of different antibiotics has shown synergism and broad-spectrum activity. The purpose of this review is to gather current data on the actions of Cannabis sativa (C. sativa) extracts and its primary constituents such as terpenes and cannabinoids towards pathogens in order to determine their antimicrobial properties and cytotoxic effects together with current challenges and future perspectives in biomedical application.”

https://pubmed.ncbi.nlm.nih.gov/36297340/

“C. sativa is a plant with an untapped potential. This versatile plant can be used for various purposes. Given its complex metabolic profile and excessive use as a recreational substance, its therapeutic benefits should not be ignored or overshadowed. Due to the limited effectiveness of antibiotics against MDR bacteria, the use of these drugs can be limited. This is why the discovery of an antimicrobial agent that can be used by plants has been regarded as a great step in the development of anti-infectives [8]. Multiple cannabinoids have been shown to have potent antimicrobial properties against Gram-positive pathogens, such as MRSA. In vitro studies have shown that cannabinoids can be useful in the removal of harmful microbes from the environment. Combination therapy with antibiotics that have different modes of action has shown broad-spectrum activities and synergism. There is also evidence that compounds found in C. sativa can have antimicrobial properties. This suggests that further investigations are needed to understand their potential. As the development of antibiotic resistance continues, cannabinoids have the potential to become a new source of treatment for bacterial infections.”

https://www.mdpi.com/1424-8247/15/10/1228/htm