Anti-Bacterial Properties of Cannabigerol Toward Streptococcus mutans

Preventive effects of taxifolin on dental caries in vitro and in vivo

OBJECTIVES

The present study aimed to explore the inhibitory effect of taxifolin (TAX) on Streptococcus mutans (S. mutans) in vitro and evaluated the anti-caries efficacy of TAX in vivo.

DESIGN

The anti-microbial and anti-biofilm properties of TAX were examined on the S. mutans, and the results were preliminarily verified by quantitative real-time PCR. Polarized light microscopy and transverse microradiography were used to detect the effect of TAX on inhibiting enamel demineralization. The effect of TAX on the remineralization of demineralized enamel was analyzed by a microhardness tester, atomic force microscope, and transverse microradiography. The rat dental caries model was constructed to explore the anti-caries effect of TAX in vivo.

RESULTS

The minimum inhibitory concentration of TAX against S. mutans was 1 mg/mL. The 1 mg/mL TAX impeded the biofilm formation, destroyed the biofilm structure, and effectively prevented enamel demineralization caused by S. mutans. Both the 0.5 mg/mL and 1 mg/mL TAX-treated groups exhibited a higher percentage of surface microhardness recovery, along with lower surface roughness, mineral loss, and lesion depth. Additionally, 1 mg/mL TAX demonstrated the ability to inhibit the initiation and progression of caries in rats, while also proving to be biologically safe.

CONCLUSIONS

TAX had a significant inhibitory effect on S. mutans, could inhibit enamel demineralization and promote remineralization of demineralized enamel, and showed a promising anti-caries effect in vivo.

Minor Cannabinoid Profile of Unregulated Cannabidiol Products

Background: Although the majority of cannabinoid research has focused on delta-9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD), there is increasing interest in the therapeutic effects of other phytocannabinoid compounds (i.e., minor cannabinoids), as there is little known about their effects or interaction with CBD. The current study objective was to determine the concentrations of 15 minor cannabinoids in unregulated, over-the-counter CBD products. Methods: A cross-section sample of 80 local and national brands of hemp-derived oil products was purchased both online and in local retail outlets in central Kentucky. Epidiolex® was included as a regulated control. Samples from each product were extracted by solvent extraction and quantified by liquid-chromatography tandem mass-spectrometry. The targeted cannabinoids were: cannabidiolic acid (CBDA), cannabidivarin (CBDV), cannabidivarinic acid, Δ9-tetrahydrocannabivarin, Δ9-tetrahydrocannabivarinic acid, Δ9-tetrahydrocannabinolic acid-A, Δ8-tetrahydrocannabinol (Δ8-THC), cannabigerol (CBG), cannabigerolic acid, cannabinol (CBN), cannabinolic acid, cannabicyclol (CBL), cannabicyclolic acid, cannabichromene (CBC) and cannabichromenic acid. Results: Among the unregulated products included in this analysis, the most frequently detected minor cannabinoids were CBDV (100% of samples tested), CBG (77%), CBC (72%), CBN (67%), CBL (67%), and CBDA (51%). Δ8-THC was not detected in any of the products tested. Concentrations of these cannabinoids varied widely from trace concentrations to several mg/mL (e.g., CBDA: 0.006-12.258 mg/mL). Conclusions: These data indicate CBD products often contain minor cannabinoids, although the array and concentrations of these cannabinoids vary widely across products. The concentrations of these minor cannabinoids are largely absent from product labels, leaving consumers uninformed about product contents.

Evaluation of the antibacterial activity and mechanism of cannabigerol against drug-resistant Streptococcus iniae in vitro

This study aimed to investigate the antibacterial effects and mechanism of cannabigerol against drug-resistant Streptococcus iniae. The determination of antibacterial activity was based on the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), growth curve analysis, time-kill assay, biofilm inhibition and eradication assessments. The antibacterial mechanism was explored by DNA leakage assay, assessment of cell membrane permeability, evaluation of cell membrane integrity, measurement of membrane potential, determination of respiratory chain dehydrogenase activity, and examination by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results demonstrated that cannabigerol effectively inhibited the growth and biofilm formation of Streptococcus iniae in vitro. Mechanistically, cannabigerol induced DNA leakage, impaired cell membrane integrity, hyperpolarized membrane potential, and reduced respiratory chain dehydrogenase activity in S. iniae. In conclusion, these findings suggest that cannabigerol inhibited the growth of S. iniae by disrupting the cell membrane.

Extraction of Cannabinoids and Terpenes from Hemp Flowers and Leaves (Cannabis sativa L., Futura 75): Chemical Profiling and Evaluation of Anticancer Properties

This study investigated efficient extraction methods for cannabinoids and terpenes from the above-ground parts of Futura 75, focusing on two techniques: pressurized extraction and magnetic stirrer-assisted extraction. The effects of solvent type, temperature, time, and pressure were evaluated using five organic solvents and two binary solvent systems. Cannabinoid profiles of obtained extracts were analyzed using gas chromatography coupled with mass spectrometry (GC-MS), while terpene profiles were characterized through solid-phase microextraction (SPME) combined with GC-MS. Next, two selected extracts with the highest content of cannabinoid and terpene fractions (Futu1 and Futu2) were tested for antiproliferative activity toward cancer cell lines (MV4-11, AGS, HT-29, MDA-MB-468, MCF-7) and their cytotoxicity was evaluated on non-tumorigenic MCF-10A cells. Extract Futu1 contained 51.57% cannabinoids, 9.8% monoterpenes, and 90.2% sesquiterpenes in the terpene fraction. Futu2 exhibited a higher proportion of monoterpenes in the terpene fraction (19.6% monoterpenes and 80.4% sesquiterpenes) and consisted of 49.49% cannabinoids. Both extracts exhibited higher selectivity for cancer cells over non-tumorigenic cells, with Futu2 demonstrating stronger antiproliferative properties. Interestingly, lower concentrations of extracts and tested free, single cannabinoids stimulated the growth of leukemia (MV4-11) and breast cancer (MDA-MB-468) cell lines while their higher concentrations suppressed proliferation.

Alisol A 24-Acetate combats Methicillin-Resistant Staphylococcus aureus infection by targeting the mevalonate biosynthesis

Infections caused by Methicillin-resistant Staphylococcus aureus (MRSA) have emerged as one of the most pressing global public health challenges. In concert with global rise of antimicrobial resistance at alarming rate, there is an urgent need for alternative strategies to combat MRSA. Here, the high throughput screening indicated that the Alisol A 24-acetate (AA) effectively inhibits the mevalonate (MVA) synthesis in MRSA. The mechanistic analysis revealed that AA competitively inhibits the 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMGR) protein to blockade the MVA pathway, thereby disrupting the bacterial membrane integrity and functions. Further investigations showed that this disruption consequently restores the β-lactam susceptibility in MRSA by retarding the expression of PBP2a protein and dampens the virulence of MRSA by reducing the exotoxins secretion. In addition to the effect on MRSA, AA has been found to exert host-acting activity to reduce the MRSA-induced inflammation. The promising anti-MRSA activity of AA was further confirmed in vivo. Collectively, the current study highlighted the potential of AA as a proposing drug for combating MRSA and emphasize the MVA pathway as an ideal therapeutic target for MRSA treatment.

Cannabis Uses in Dentistry: A Bibliometric Analysis

Background: This bibliometric review seeks to understand metrics of papers, authors, journals, and universities, about the benefits of the therapeutic application of Cannabis sativa (CS), as well as the most harmful effects associated to its use. Methods: The main search strategy applied to the topic was conducted in Web Of Science Core Collection on February 2024. A crossmatch of the number of citations was performed in Scopus and Google Scholar. The analyses were carried out in VOSviewer and Altmetric for PubMed and Google Scholar. Results: Of a total of 196 records, 53 articles were included for analysis. There were 25 publications on either therapeutic or harmful effects. In the ranking of subjects, those of greatest interest were general oral health and periodontics, with 53% of the total. The most cited paper was authored by Thomson et al. (2008) with 85 citations, allowing the University of Otago to be the most cited. Although JAMA was the most cited journal, in the dental field this corresponded to the Journal of Clinical Periodontology. In relation to the distribution by country, the United States received the largest number of citations and New Zealand second. Related to dentistry, in the cluster analysis, keywords more occurrent were "periodontal disease" and "periodontitis". Conclusions: In the past 4 years, there has been a superlative growth in CS papers related to oral health effects. This growth follows the social and political events related to CS legalization in some countries and reveals that the use of CS in dentistry is an emerging research field.

Inhibitory Potential of Cannabis Biomass Extracts on Livestock-Associated Staphylococcal and Streptococcal Pathogens

Diseases caused by staphylococci and streptococci are a serious burden on livestock production, causing significant losses. In addition, the associated antibiotic resistance of these pathogens often makes treatment impossible or prolonged. Cannabis sativa L. contains many compounds with antibacterial properties and shows great potential as a natural antimicrobial agent for agricultural use against both of these bacterial species. The aim of this study was to compare the in vitro antibacterial activity of ethanol extracts from five cultivars of hemp, namely, Bialobrzeskie, Felina 32, Futura 75, mixed and Santhica 27, against Staphylococcus aureus, Streptococcus agalactiae and Streptococcus dysgalactiae. All five cultivars exhibited a certain degree of inhibitory effect against all the pathogens tested with minimum inhibitory concentrations (MICs) ranging from 128 to 2048 μg/mL. The extract from the Santhica 27 cultivar was the most effective antibacterial agent with the lowest MIC value of 128 μg/mL against Str. agalactiae and two clinical isolates of S. aureus, followed by Bialobrzeskie and mixed cultivars with the same growth-inhibitory potential against Str. agalactiae. The extracts from the Felina 32 and Futura 75 cultivars presented only weak activity with MIC values ranging from 256 to 2048 μg/mL. The extract from the Santhica 27 cultivar appears to be a promising product for future use in the treatment of staphylococcal and streptococcal infections in livestock.

Hexane extract from Lindera communis roots: wound healing properties and membrane-disruptive activities against methicillin-resistant Staphylococcus aureus

Introduction

The extensively used Lindera communis Hemsl. (Lauraceae) in traditional Chinese medicine has been specifically employed for wound healing and treating skin diseases in cattle and horses, suggesting its potential antibacterial properties. To explore the antibacterial activities of L. communis plants, we investigated the chemicals, antibacterial activities and wound healing and of the n-hexane fraction of L. communis roots (LCH).

Methods

Our study included detecting phytochemical constituents, determining minimum inhibitory concentration (MIC) for different extract fractions, analyzing growth curves, assessing membrane integrity, monitoring potential changes in the membrane using scanning electron microscopy, and evaluating wound healing in rat excisional wounds.

Results

Based on our findings, humulene-type sesquiterpenes, guaiane-type sesquiterpenes, and lauric acid were identified from the LCH, responsible for antibacterial and wound healing activities. The results are that LCH affected the growth of methicillin-resistant Staphylococcus aureus (MIC: 0.1 mg/mL) through morphological alterations and disrupting cell surface structures, causing membrane hyperpolarization and altering membrane integrity. This result was subsequently validated through SEM analysis and cytotoxicity against HaCaT cells (IC50 1.83 ± 0.21 mg/mL). LCH also has exhibited remarkable effectiveness in healing rat excisional wounds, reinforcing its traditional use as a wound-healing agent.

Discussion

The findings substantiate the scientific essence of traditional applications, while also exhibiting significant potential as a promising candidate for the development of innovative and readily accessible wound healing agents.

Antimicrobial Potential of Cannabinoids: A Scoping Review of the Past 5 Years

In the scenario of fighting bacterial resistance to antibiotics, natural products have been extensively investigated for their potential antibacterial activities. Among these, cannabinoids-bioactive compounds derived from cannabis-have garnered attention for their diverse biological activities, including anxiolytic, anti-inflammatory, analgesic, antioxidant, and neuroprotective properties. Emerging evidence suggests that cannabinoids may also possess significant antimicrobial properties, with potential applications in enhancing the efficacy of conventional antimicrobial agents. Therefore, this review examines evidence from the past five years on the antimicrobial properties of cannabinoids, focusing on underlying mechanisms such as microbial membrane disruption, immune response modulation, and interference with microbial virulence factors. In addition, their synergistic potential, when used alongside standard therapies, underscores their promise as a novel strategy to address drug resistance, although further research and clinical trials are needed to validate their therapeutic use. Overall, cannabinoids offer a promising avenue for the development of innovative treatments to combat drug-resistant infections and reduce the reliance on traditional antimicrobial agents.

Cannabidiol (CBD) Acts as an Antioxidant on Gardnerella vaginalis, Resulting in Reduced Metabolic Activity, Loss of Survivability, and Elimination of Biofilms

Background: Gardnerella vaginalis is a natural inhabitant of the vagina, but when an imbalance occurs in the vaginal microbiota, this bacterium can cause vaginosis, a condition that must be treated when symptomatic and prior to a gynecological intervention. Cannabidiol (CBD) is an anti-inflammatory compound that also has antibacterial activities against several Gram-positive and certain Gram-negative bacteria. Objectives: Since G. vaginalis is an opportunistic pathogenic Gram-variable bacterium, we investigated its response to CBD. Methods: The antibacterial activity of CBD was studied by broth dilution assay, changes in intracellular ATP levels, and the ability of bacteria to recover on chocolate agar plates. The antibiofilm activity was investigated by MTT metabolic assay, crystal violet staining, and HR-SEM. Flow cytometric analyses were performed to measure changes in membrane potential, membrane perforation, and metabolic activity. Reactive oxygen species (ROS) production was analyzed using the nitro blue tetrazolium (NBT) reagent. Gene expression was determined by semi-quantitative real-time PCR, while protein composition was determined by LC-MS/MS analysis. Results: We observed that G. vaginalis clinical isolates exhibited high susceptibility to CBD with a minimum inhibitory concentration (MIC) of 2.5 µg/mL CBD. CBD induced rapid membrane hyperpolarization and caused cytoplasmic leakage of ATP without increasing propidium iodide uptake. This was accompanied by reduced metabolic activity and loss of survivability. Proteomic analysis revealed decreased expression of some ribosomal-associated proteins. CBD exhibited antioxidant activity by reducing intracellular ROS levels in a dose-dependent manner. The antibacterial effect was neutralized by the free radical scavenger α-tocopherol, suggesting the involvement of radicals in executing the antibacterial effect. Importantly, CBD not only prevented the biofilm formation of G. vaginalis but also reduced the metabolic activity and biofilm biomass of preformed, mature biofilms. Real-time PCR analysis of G. vaginalis treated with CBD for 6 h showed an increase in the expression of biofilm-associated genes, suggesting that the antibiofilm activity of CBD is mainly due to its antibacterial effect. CBD did not alter the ability of G. vaginalis to adhere to HeLa cervical carcinoma cells and CBD-treated bacteria were still phagocytosed by RAW264.7 macrophages. Conclusions: Our study shows that CBD exhibits antibacterial and antibiofilm activities against G. vaginalis clinical isolates and is thus a potential drug for the treatment of vaginosis caused by this bacterium.

Twin-screw extrusion retains industrial hemp byproduct (hemp flakes) functionality

Consumer recognition of the health benefits of industrial hemp cannabidiol (CBD) products has increased its value to consumers. Consequently, there is a need to explore industrial hemp byproducts to improve sustainability and foster a circular economy. Extrusion processing was conducted with formulations made with hemp flakes, a byproduct of CBD oil extraction based on corn flour with 5%, 10%, and 15% hemp flakes replacement using a laboratory-scale conical twin-screw extruder. The impacts of formulation, barrel temperature, and screw speed on extrudates were evaluated. Cannabichromene (CBC), cannabinol (CBN), cannabidiolic acid (CBDA), cannabigerol (CBG), and CBD were determined with high-performance liquid chromatography before and postextrusion. Antioxidant potential (total polyphenol content [TPC] and 1,1-diphenyl-1-picrylhydrazyl radical scavenging assay [DPPH]) and ferric-reducing antioxidant potential (FRAP) were determined similarly. Increasing hemp flakes in the formula reduced pasting properties significantly (p ≤ 0.05). Expansion ratio (ER) showed significant linear effects with the amount of hemp flakes in the formula (p ≤ 0.05) and die temperature (p ≤ 0.05), while the 10% hemp formula recorded the highest ER of 3.24 (p ≤ 0.05). Extrusion generally reduced TPC, DPPH, FRAP, and cannabinoids compared to raw formulas. Low screw speeds and medium barrel temperatures displayed high retention of cannabinoids and antioxidants. Low screw speeds might have allowed adequate shearing, mixing, and an extended high-pressure exposure leading to the release of bound polyphenols, antioxidants, and cannabinoids. Some extrusion parameters can maintain cannabinoids and antioxidants in hemp byproducts while transforming them into puffed food products. These findings directly affect the industry, providing valuable insights for practical application. PRACTICAL APPLICATION: Extrusion cooking remains one of the most economical methods of valorizing agricultural byproducts. This work developed extrusion parameters applicable to the food industry for making quality puffed food products. It could apply to snacks, breakfast cereals, animal feed, and others with desirable consumer properties and retained functionality for improving health and wellness.

Laurdan in living cells: Where do we stand?

Laurdan is a valuable tool for analyzing phase transitions and general behavior in synthetic lipid membranes. Its use is very straightforward, thus, its application in cells has expanded rapidly in recent years. It has been demonstrated that Laurdan is very useful for analyzing membrane trends when cells are subjected to some treatment, or when different cell mutations are compared. However, a deep interpretation of the data is not as straightforward as in synthetic lipid bilayers. In this review, we complied results found in mammalian and bacterial cells and noted that the use of Laurdan could be improved if a comparison between publications could be done. At the moment this is not easy, mainly due to the lack of complete information in the publications, and to the different methodologies employed in the data recording and processing. We conclude that research in cell membrane topics would benefit from a better use of the Laurdan probe.

Antibacterial phenolic compounds from the flowering plants of Asia and the Pacific: coming to the light

CONTEXT

The emergence of pan-resistant bacteria requires the development of new antibiotics and antibiotic potentiators.

OBJECTIVE

This review identifies antibacterial phenolic compounds that have been identified in Asian and Pacific Angiosperms from 1945 to 2023 and analyzes their strengths and spectra of activity, distributions, molecular masses, solubilities, modes of action, structures-activities, as well as their synergistic effects with antibiotics, toxicities, and clinical potential.

METHODS

All data in this review was compiled from Google Scholar, PubMed, Science Direct, Web of Science, and library search; other sources were excluded. We used the following combination of keywords: 'Phenolic compound', 'Plants', and 'Antibacterial'. This produced 736 results. Each result was examined and articles that did not contain information relevant to the topic or coming from non-peer-reviewed journals were excluded. Each of the remaining 467 selected articles was read critically for the information that it contained.

RESULTS

Out of ∼350 antibacterial phenolic compounds identified, 44 were very strongly active, mainly targeting the cytoplasmic membrane of Gram-positive bacteria, and with a molecular mass between 200 and 400 g/mol. 2-Methoxy-7-methyljuglone, [6]-gingerol, anacardic acid, baicalin, vitexin, and malabaricone A and B have the potential to be developed as antibacterial leads.

CONCLUSIONS

Angiosperms from Asia and the Pacific provide a rich source of natural products with the potential to be developed as leads for treating bacterial infections.

Skin cells protection against UVA radiation - The comparison of various antioxidants and viability tests

This study compares the effects of vitamins - including ascorbic acid, its derivative 3-O-ethyl-ascorbic acid (EAA), and tocopherol - as well as the main non-psychoactive phytocannabinoids on the viability of various skin cells, including healthy (keratinocytes/melanocytes/fibroblasts) and cancer cells (melanoma/SCC), under standard culture conditions and after the exposure to UVA radiation. All the conducted tests (MTT, SRB, and LDH) consistently indicate that the regenerative effect of EAA is stronger than that of ascorbic acid, while tocopherol acts selectively on healthy/cancer cells, inducing or inhibiting their proliferation, respectively. In the case of phytocannabinoids, only cannabidiol shows protective/regenerative properties for healthy cells. Moreover, the response of melanocytes to cannabigerol is divergent; however, only the LDH test indicates that cannabigerol strongly increases the membrane permeability of those cells. In summary it should be emphasized that various tests may give partially divergent results due to a variety of measured parameters. Nevertheless, despite the positive viability test results for the potential protective compound, caution should be taken as it may promote healthy skin cells but also protect cancer cells.

Cannabigerol (CBG): A Comprehensive Review of Its Molecular Mechanisms and Therapeutic Potential

Cannabigerol (CBG), a non-psychoactive cannabinoid found in cannabis, has emerged as a promising therapeutic agent with a diverse range of potential applications. Unlike its well-known counterpart tetrahydrocannabinol (THC), CBG does not induce intoxication, making it an attractive option in the clinic. Recent research has shed light on CBG's intriguing molecular mechanisms, highlighting its potential to modulate multiple physiological processes. This review delves into the current understanding of CBG's molecular interactions and explores its therapeutic power to alleviate various conditions, including cancer, metabolic, pain, and inflammatory disorders, amongst others. We discuss how CBG interacts with the endocannabinoid system and other key signaling pathways, such as CB1, CB2, TPR channels, and α2-adrenoceptor, potentially influencing inflammation, pain, neurodegeneration, and other ailments. Additionally, we highlight the ongoing research efforts aimed at elucidating the full spectrum of CBG's therapeutic potential and its safety profile in clinical settings. Through this comprehensive analysis, we aim to provide a deeper understanding of CBG's role in promoting human health and pave the way for future research endeavors.

Anticaries and Antigingivitis Properties of Cannabinoid-Containing Oral Health Products: A Review

To evaluate the anticaries and antigingivitis properties of cannabinoid-containing oral health products. A systematic research strategy was employed. Specific search terms were used, including "Cannabinoids AND dental caries," "Cannabinoids AND oral health," "Cannabinoids AND dental plaque," "Cannabinoids AND gingivitis AND periodontitis," "Cannabinoids AND S. mutans," "Cannabidiol AND oral health," and "Cannabidiol AND oral biofilm." The search was conducted in PubMed, Cochrane, and EBSCO Host databases. The search yielded a total of 73 articles, out of which 15 articles (20.5%) were relevant to the scope of this systematic review. Among the relevant articles, only eight (10.9%) directly addressed the research question. The findings from these articles suggest that cannabinoids have the potential to reduce the metabolism of cariogenic bacteria, specifically Streptococcus mutans, and decrease the number of bacterial colonies in dental plaque. In vitro studies also demonstrated a significant inhibitory effect of cannabinoids on oral biofilms and create a considerable inhibitory zone of growth when investigated on oral biofilms in vitro. Furthermore, CBD exhibited antibacterial properties against Porphyromonas gingivalis, a primary pathogen associated with periodontal disease. The current review shows insufficient data to conclude on the anticaries and antigingivitis effects of cannabinoids. Despite extensive research on their systemic therapeutic benefits, their oral health impact remains underexplored, lacking clinical trials and primary research.

Cannabinoids in Integumentary Wound Care: A Systematic Review of Emerging Preclinical and Clinical Evidence

This systematic review critically evaluates preclinical and clinical data on the antibacterial and wound healing properties of cannabinoids in integument wounds. Comprehensive searches were conducted across multiple databases, including CINAHL, Cochrane library, Medline, Embase, PubMed, Web of Science, and LILACS, encompassing records up to May 22, 2024. Eighteen studies met the inclusion criteria. Eleven were animal studies, predominantly utilizing murine models (n = 10) and one equine model, involving 437 animals. The seven human studies ranged from case reports to randomized controlled trials, encompassing 92 participants aged six months to ninety years, with sample sizes varying from 1 to 69 patients. The studies examined the effects of various cannabinoid formulations, including combinations with other plant extracts, crude extracts, and purified and synthetic cannabis-based medications administered topically, intraperitoneally, orally, or sublingually. Four animal and three human studies reported complete wound closure. Hemp fruit oil extract, cannabidiol (CBD), and GP1a resulted in complete wound closure in twenty-three (range: 5-84) days with a healing rate of 66-86% within ten days in animal studies. One human study documented a wound healing rate of 3.3 cm2 over 30 days, while three studies on chronic, non-healing wounds reported an average healing time of 54 (21-150) days for 17 patients by oral oils with tetrahydrocannabinol (THC) and CBD and topical gels with THC, CBD, and terpenes. CBD and tetrahydrocannabidiol demonstrated significant potential in reducing bacterial loads in murine models. However, further high-quality research is imperative to fully elucidate the therapeutic potential of cannabinoids in the treatment of bacterial skin infections and wounds. Additionally, it is crucial to delineate the impact of medicinal cannabis on the various phases of wound healing. This study was registered in PROSPERO (CRD42021255413).

The antimicrobial activity of tea tree oil (Melaleuca alternifolia) and its metal nanoparticles in oral bacteria

Tea tree (Melaleuca alternifolia) oil (TTO) is an antimicrobial agent, and hence, its use in fabricating nanoparticles (NP) may be useful in providing more efficacious antimicrobial agents. The current research aimed to test the antimicrobial efficacy of TTO and its TTO-Metal-NPs against oral microbes: Porphyromonas gingivalis, Enterococcus faecalis, and Streptococcus mutans. The antimicrobial activity of TTO and zinc (Zn) and iron (Fe) nanoparticles (NPs) and the combined effects of antimicrobial agents were investigated using agar well diffusion assays. Fourier-transform infrared spectroscopy (FT-IR) was used to identify the phyto-constituents of TTO. Field emission scanning electron microscopy (FE-SEM), dynamic light scatter (DLS), and zeta potential were utilized to analyze the biogenic nanoparticles' morphology, size, and potential. The antimicrobial mode of action was determined by assessing the morphological changes under scanning electron microscopy (SEM). The TTO extracts converted Zn and Fe ions to NPs, having an average size of 97.50 (ZnNPs) and 102.4 nm (FeNPs). All tested agents had significant antibacterial efficacy against the tested oral microbes. However, the TTO extract was more efficacious than the NPs. Combination treatment of TTO with antibiotics resulted in partial additive effects against P. gingivalis and partial antagonistic effects against E. faecalis, S. mutans, and common mouthwashes (Oral B and chlorhexidine). TTO and NP-treated bacteria underwent morphological changes on treatment. M. alternifolia phytochemicals could be useful for further research and development of antimicrobial NPs. The current study highlights the variance in activity observed for different types of bacteria and antagonistic effects seen with common mouthwashes, which represent a threat to therapeutic efficacy and heighten the risk of clinical microbial resistance.

Phytochemical Analysis and Anti-Biofilm Potential That Cause Dental Caries from Black Cumin Seeds (Nigella sativa Linn.)

The oral cavity is an excellent place for various microorganisms to grow. Spectrococcus mutans and Spectrococcus sanguinis are Gram-negative bacteria found in the oral cavity as pioneer biofilm formers on the tooth surface that cause caries. Caries treatment has been done with antibiotics and therapeutics, but the resistance level of S. mutans and S. sanguinis bacteria necessitates the exploration of new drug compounds. Black cumin (Nigella sativa Linn.) is known to contain secondary metabolites that have antioxidant, antibacterial, anti-biofilm, anti-inflammatory and antifungal activities. The purpose of this review article is to present data on the potential of Nigella sativa Linn seeds as anti-biofilm. This article will discuss biofilm-forming bacteria, the resistance mechanism of antibiotics, the bioactivity of N. sativa extracts and seed isolates together with the Structure Activity Relationship (SAR) review of N. sativa compound isolates. We collected data from reliable references that will illustrate the potential of N. sativa seeds as anti-biofilm drug.

Spent Material Extractives from Hemp Hydrodistillation as an Underexplored Source of Antimicrobial Cannabinoids

Hemp (Cannabis sativa L.) has been used for millennia as a rich source of food and fibers, whereas hemp flowers have only recently gained an increased market interest due to the presence of cannabinoids and volatile terpenes. Currently, the hemp flower processing industry predominantly focuses on either cannabinoid or terpene extraction. In an attempt to maximize the valorization of hemp flowers, the current study aimed to evaluate the phytochemical composition and antimicrobial properties of several extracts obtained from post-distillation by-products (e.g., spent material, residual distillation water) in comparison to the essential oil and total extract obtained from unprocessed hemp flowers. A terpene analysis of the essential oil revealed 14 monoterpenes and 35 sesquiterpenes. The cannabinoid profiling of extracts showed seven acidic precursors and 14 neutral derivatives, with cannabidiol (CBD) reaching the highest concentration (up to 16 wt.%) in the spent material extract. The antimicrobial assessment of hemp EO, cannabinoid-containing extracts, and single compounds (i.e., CBD, cannabigerol, cannabinol, and cannabichromene) against a panel of 20 microbial strains demonstrated significant inhibitory activities against Gram-positive bacteria, Helicobacter pylori, and Trichophyton species. In conclusion, this work suggests promising opportunities to use cannabinoid-rich materials from hemp flower processing in functional foods, cosmetics, and pharmaceuticals with antimicrobial properties.

Mitigation of oxidative stress and inflammatory factors, along with the antibrowning and antimicrobial effects of cassia seed microbial fermentation solution

Introduction

Cassia seeds, originating from the mature seeds of leguminous cassia species, possess pharmacological effects attributed to their rich composition of various active ingredients, notably anthraquinones. While current research predominantly focuses on pharmaceutical extractions, there has been limited progress in fermentation studies.

Methods

Our study aimed to enhance the content of active compounds such as anthraquinones, flavonoids, and polyphenols using microbial fermentation techniques. We specifically optimized a fermentation system through a single-factor experimental design.

Results

The antioxidant properties of the fermentation solution were validated through assays involving HaCaT cells and zebrafish. We observed effective suppression of inflammatory reactions in both RAW264.7 cells and transgenic zebrafish by the fermentation solution. Moreover, significant inhibition of tyrosinase activity and melanin production was evident in B16-F10 cells and zebrafish. Positive outcomes were also obtained in antibacterial assays and chick embryo experiments.

Discussion

These findings highlight the potential of cassia seed fermentation solution as a safe and eco-friendly material in food chemistry and biomedical sciences.

Effects of UV/H2O2 Degradation on the Physicochemical and Antibacterial Properties of Fucoidan

The applications of fucoidan in the food industry were limited due to its high molecular weight and low solubility. Moderate degradation was required to depolymerize fucoidan. A few studies have reported that fucoidan has potential antibacterial activity, but its antibacterial mechanism needs further investigation. In this study, the degraded fucoidans were obtained after ultraviolet/hydrogen peroxide treatment (UV/H2O2) at different times. Their physicochemical properties and antibacterial activities against Staphylococcus aureus and Escherichia coli were investigated. The results showed that the average molecular weights of degraded fucoidans were significantly decreased (up to 22.04 times). They were mainly composed of fucose, galactose, and some glucuronic acid. Fucoidan degraded for 90 min (DFuc-90) showed the strongest antibacterial activities against Staphylococcus aureus and Escherichia coli, with inhibition zones of 27.70 + 0.84 mm and 9.25 + 0.61 mm, respectively. The minimum inhibitory concentrations (MIC) were 8 mg/mL and 4 mg/mL, respectively. DFuc-90 could inhibit the bacteria by damaging the cell wall, accumulating intracellular reactive oxygen species, reducing adenosine triphosphate synthesis, and inhibiting bacterial metabolic activity. Therefore, UV/H2O2 treatment could effectively degrade fucoidan and enhance its antibacterial activity.

Antibiofilm and Immune-Modulatory Activity of Cannabidiol and Cannabigerol in Oral Environments-In Vitro Study

OBJECTIVE

To evaluate the in vitro antimicrobial and antibiofilm properties and the immune modulatory activity of cannabidiol (CBD) and cannabigerol (CBG) on oral bacteria and periodontal ligament fibroblasts (PLF).

METHODS

Cytotoxicity was assessed by propidium iodide flow cytometry on fibroblasts derived from the periodontal ligament. The minimum inhibitory concentration (MIC) of CBD and CBG for S. mutans and C. albicans and the metabolic activity of a subgingival 33-species biofilm under CBD and CBG treatments were determined. The Quantification of cytokines was performed using the LEGENDplex kit (BioLegend, Ref 740930, San Diego, CA, USA).

RESULTS

CBD-treated cell viability was greater than 95%, and for CBG, it was higher than 88%. MIC for S. mutans with CBD was 20 µM, and 10 µM for CBG. For C. albicans, no inhibitory effect was observed. Multispecies biofilm metabolic activity was reduced by 50.38% with CBD at 125 µg/mL (p = 0.03) and 39.9% with CBG at 62 µg/mL (p = 0.023). CBD exposure at 500 µg/mL reduced the metabolic activity of the formed biofilm by 15.41%, but CBG did not have an effect. CBG at 10 µM caused considerable production of anti-inflammatory mediators such as TGF-β and IL-4 at 12 h. CBD at 10 µM to 20 µM produced the highest amount of IFN-γ.

CONCLUSION

Both CBG and CBD inhibit S. mutans; they also moderately lower the metabolic activity of multispecies biofilms that form; however, CBD had an effect on biofilms that had already developed. This, together with the production of anti-inflammatory mediators and the maintenance of the viability of mammalian cells from the oral cavity, make these substances promising for clinical use and should be taken into account for future studies.

Anti-staphylococcal activity of soilless cultivated cannabis across the whole vegetation cycle under various nutritional treatments in relation to cannabinoid content

Antibiotic resistance in staphylococcal strains and its impact on public health and agriculture are global problems. The development of new anti-staphylococcal agents is an effective strategy for addressing the increasing incidence of bacterial resistance. In this study, ethanolic extracts of Cannabis sativa L. made from plant parts harvested during the whole vegetation cycle under various nutritional treatments were assessed for in vitro anti-staphylococcal effects. The results showed that all the cannabis extracts tested exhibited a certain degree of growth inhibition against bacterial strains of Staphylococcus aureus, including antibiotic-resistant and antibiotic-sensitive forms. The highest antibacterial activity of the extracts was observed from the 5th to the 13th week of plant growth across all the nutritional treatments tested, with minimum inhibitory concentrations ranging from 32 to 64 µg/mL. Using HPLC, Δ9-tetrahydrocannabinolic acid (THCA) was identified as the most abundant cannabinoid in the ethanolic extracts. A homolog of THCA, tetrahydrocannabivarinic acid (THCVA), reduced bacterial growth by 74%. These findings suggest that the cannabis extracts tested in this study can be used for the development of new anti-staphylococcal compounds with improved efficacy.

The transcriptomic response to cannabidiol of Treponema denticola, a phytocannabinoid-resistant periodontal pathogen

AIM

The use of cannabis, which contains multiple antimicrobials, may be a risk factor for periodontitis. We hypothesized that multiple oral spirochetes would be phytocannabinoid-resistant and that cannabidiol (CBD) would act as an environmental stressor to which Treponema denticola would respond transcriptionally, thereby providing first insights into spirochetal survival strategies.

MATERIALS AND METHODS

Oral spirochete growth was monitored spectrophotometrically in the presence and absence of physiologically relevant phytocannabinoid doses, the transcriptional response to phytocannabinoid exposure determined by RNAseq, specific gene activity fluxes verified using qRT-PCR and orthologues among fully sequenced oral spirochetes identified.

RESULTS

Multiple strains of oral treponemes were resistant to CBD (0.1-10 μg/mL), while T. denticola ATCC 35405 was resistant to all phytocannabinoids tested (CBD, cannabinol [CBN], tetrahydrocannabinol [THC]). A total of 392 T. denticola ATCC 35405 genes were found to be CBD-responsive by RNAseq. A selected subset of these genes was independently verified by qRT-PCR. Genes found to be differentially activated by both methods included several involved in transcriptional regulation and toxin control. Suppressed genes included several involved in chemotaxis and proteolysis.

CONCLUSIONS

Oral spirochetes, unlike some other periodontal bacteria, are resistant to physiological doses of phytocannabinoids. Investigation of CBD-induced transcriptomic changes provided insight into the resistance mechanisms of this important periodontal pathogen. These findings should be considered in the context of the reported enhanced susceptibility to periodontitis in cannabis users.

LiaSR two-component system modulates the oxidative stress response in Streptococcusmutans

Many commensal bacteria of the human oral microbiome can produce reactive oxygen species (ROS). ROS will inhibit the colonization of Streptococcusmutans (S.mutans), a major pathogenic bacteria in dental caries. The LiaSR two-component system in S.mutans can sense and respond to environmental oxidative stress. However, the molecular details of the LiaSR two-component system and oxidative stress response have been unclear. In this study, we aimed to elucidate the underlying mechanisms of the LiaSR two-component system and the mediated oxidative stress response in S.mutans. We performed the H2O2 killing assay, Confocal laser scanning microscopy, and 2,7-Dichlorofluoresce diacetate staining assay to evaluate the sensitivity of S.mutans to H2O2. The propidium iodide probe and TUNEL kit were used to detect the membrane permeability and DNA fragmentation. Quantitative real-time PCR was conducted to analyze the expression level of underlying regulated genes. The liaS and liaR deficient mutants were particularly sensitive to H2O2 compared to their wild strain S.mutans 593, which was previously isolated from a caries-active patient. The intracellular levels of ROS and membrane permeability increased in the mutants. The TUNEL assay showed that the rate of DNA fragmentation in the liaR mutant was higher compared to the wild strain and liaS mutant. Relative expression of the spxA2 gene in the mutants was lower than in the wild strain. The dpr and dinB genes were downregulated in the liaR mutant. These results indicated that the LiaSR two-component system mediated influence on spxA2 expression in S.mutans and contributed to membrane homeostasis, which was involved in the oxidative response process. S.mutans could also elevate the dpr and the dinB genes, which depend on the liaR component in the LiaSR system, may help reduce the DNA damage caused by ROS. This study provides valuable insights into the mechanisms of the LiaSR two-component system in the oxidative stress response of S.mutans.

The Role of Bacterial, Dentinal, Salivary, and Neutrophil Degradative Activity in Caries Pathogenesis

Until recently, it was widely accepted that bacteria participate in caries pathogenesis mainly through carbohydrate fermentation and acid production, which promote the dissolution of tooth components. Neutrophils, on the other hand, were considered white blood cells with no role in caries pathogenesis. Nevertheless, current literature suggests that both bacteria and neutrophils, among other factors, possess direct degradative activity towards both dentinal collagen type-1 and/or methacrylate resin-based restoratives and adhesives, the most common dental restoratives. Neutrophils are abundant leukocytes in the gingival sulcus, where they can readily reach adjacent tooth roots or gingival and cervical restorations and execute their degradative activity. In this review, we present the latest literature evidence for bacterial, dentinal, salivary, and neutrophil degradative action that may induce primary caries, secondary caries, and restoration failure.

Informing the Cannabis Conjecture: From Life's Beginnings to Mitochondria, Membranes and the Electrome-A Review

Before the late 1980s, ideas around how the lipophilic phytocannabinoids might be working involved membranes and bioenergetics as these disciplines were "in vogue". However, as interest in genetics and pharmacology grew, interest in mitochondria (and membranes) waned. The discovery of the cognate receptor for tetrahydrocannabinol (THC) led to the classification of the endocannabinoid system (ECS) and the conjecture that phytocannabinoids might be "working" through this system. However, the how and the "why" they might be beneficial, especially for compounds like CBD, remains unclear. Given the centrality of membranes and mitochondria in complex organisms, and their evolutionary heritage from the beginnings of life, revisiting phytocannabinoid action in this light could be enlightening. For example, life can be described as a self-organising and replicating far from equilibrium dissipating system, which is defined by the movement of charge across a membrane. Hence the building evidence, at least in animals, that THC and CBD modulate mitochondrial function could be highly informative. In this paper, we offer a unique perspective to the question, why and how do compounds like CBD potentially work as medicines in so many different conditions? The answer, we suggest, is that they can modulate membrane fluidity in a number of ways and thus dissipation and engender homeostasis, particularly under stress. To understand this, we need to embrace origins of life theories, the role of mitochondria in plants and explanations of disease and ageing from an adaptive thermodynamic perspective, as well as quantum mechanics.

Synthetic Pathways to Non-Psychotropic Phytocannabinoids as Promising Molecules to Develop Novel Antibiotics: A Review

Due to the rapid emergence of multi drug resistant (MDR) pathogens against which current antibiotics are no longer functioning, severe infections are becoming practically untreatable. Consequently, the discovery of new classes of effective antimicrobial agents with novel mechanism of action is becoming increasingly urgent. The bioactivity of Cannabis sativa, an herbaceous plant used for millennia for medicinal and recreational purposes, is mainly due to its content in phytocannabinoids (PCs). Among the 180 PCs detected, cannabidiol (CBD), Δ⁸ and Δ⁹-tetrahydrocannabinols (Δ⁸-THC and Δ⁹-THC), cannabichromene (CBC), cannabigerol (CBG), cannabinol (CBN) and some of their acidic precursors have demonstrated from moderate to potent antibacterial effects against Gram-positive bacteria (MICs 0.5-8 µg/mL), including methicillin-resistant Staphylococcus aureus (MRSA), epidemic MRSA (EMRSA), as well as fluoroquinolone and tetracycline-resistant strains. Particularly, the non-psychotropic CBG was also capable to inhibit MRSA biofilm formation, to eradicate even mature biofilms, and to rapidly eliminate MRSA persiter cells. In this scenario, CBG, as well as other minor non-psychotropic PCs, such as CBD, and CBC could represent promising compounds for developing novel antibiotics with high therapeutic potential. Anyway, further studies are necessary, needing abundant quantities of such PCs, scarcely provided naturally by Cannabis plants. Here, after an extensive overture on cannabinoids including their reported antimicrobial effects, aiming at easing the synthetic production of the necessary amounts of CBG, CBC and CBD for further studies, we have, for the first time, systematically reviewed the synthetic pathways utilized for their synthesis, reporting both reaction schemes and experimental details.

Acidic Microenvironment-Sensitive Core-Shell Microcubes: The Self-assembled and the Therapeutic Effects for Caries Prevention

OBJECTIVES

 The aim of this study was to develop a new material with integrated interface design that could achieve the purpose of environmental-sensing controlled release against cariogenic bacteria. Furthermore, this material can rebalance oral flora and serve as a preventive and reparative measure of dental caries.

MATERIALS AND METHODS

 NaF@PAA@HA@polyelectrolytes@HA@PAA particles were synthesized using the method of two-solution phases precipitation followed by biocompatible polymers coating layer by layer. The structure of the particles was confirmed by transmission electron microscope. The fluoride release profile was measured by fluoride ion electrode. Antimicrobial activity against the cariogenic microorganisms was analyzed by scanning electron microscopy and energy dispersive spectrum. The efficacy experiments were conducted on tooth enamel slides to evaluated fluoride absorption and antibacterial activity of the prototype toothpaste containing microcube particles RESULTS:  The structure of NaF@PAA@HA@polyelectrolytes@HA@PAA particles showed a core surrounded by tooth-adhesion polymer layers in thin fin or filament structure. The loaded concentration of fluoride in the particles' core was 148,996 ± 28,484 ppm. NaF@PAA@HA@polyelectrolytes@HA@PAA particles showed selective inhibition of cariogenic microorganisms over probiotic strains and stronger fluoride adhesion on tooth enamel. A burst release (over 80%) of fluoride from the particle-containing toothpaste was observed under cariogenic acidic environment (pH < 5), while it remained extremely low under neutral environment. Compared with the best results of commercial toothpastes, our prototype toothpaste increased enamel fluoride uptake by 8-fold in normal enamel slides and by 11-fold in the slides with induced white spot lesions after either 1- or 7-day treatment. The prototype toothpaste also showed better inhibition of cariogenic microorganisms than the commercial brands. The coverage area of cariogenic bacteria under our toothpaste treatment was 73% on normal enamel slides compared with the commercial brands, while it was 69% in the induced white spot lesions.

CONCLUSIONS

 In our study, an intelligent toothpaste was developed that selectively inhibits cariogenic bacteria by microenvironment proton-triggered fluoride release. Such novel design would accomplish a favorable flora balance for optimal long-term oral health.

pH-Responsive Biomaterials for the Treatment of Dental Caries-A Focussed and Critical Review

Dental caries is a common and costly multifactorial biofilm disease caused by cariogenic bacteria that ferment carbohydrates to lactic acid, demineralizing the inorganic component of teeth. Therefore, low pH (pH 4.5) is a characteristic signal of the localised carious environment, compared to a healthy oral pH range (6.8 to 7.4). The development of pH-responsive delivery systems that release antibacterial agents in response to low pH has gained attention as a targeted therapy for dental caries. Release is triggered by high levels of acidogenic species and their reduction may select for the establishment of health-associated biofilm communities. Moreover, drug efficacy can be amplified by the modification of the delivery system to target adhesion to the plaque biofilm to extend the retention time of antimicrobial agents in the oral cavity. In this review, recent developments of different pH-responsive nanocarriers and their biofilm targeting mechanisms are discussed. This review critically discusses the current state of the art and innovations in the development and use of smart delivery materials for dental caries treatment. The authors' views for the future of the field are also presented.

Polyglactin 910 Meshes Coated with Sustained-Release Cannabigerol Varnish Inhibit Staphylococcus aureus Biofilm Formation and Macrophage Cytokine Secretion: An In Vitro Study

Synthetic surgical meshes are commonly used in abdominal wall reconstruction surgeries to strengthen a weak abdominal wall. Common mesh-related complications include local infection and inflammatory processes. Because cannabigerol (CBG) has both antibacterial and anti-inflammatory properties, we proposed that coating VICRYL (polyglactin 910) mesh with a sustained-release varnish (SRV) containing CBG would prevent these complications. We used an in vitro infection model with Staphylococcus aureus and an in vitro inflammation model of lipopolysaccharide (LPS)-stimulated macrophages. Meshes coated with either SRV-placebo or SRV-CBG were exposed daily to S. aureus in tryptic soy medium (TSB) or macrophage Dulbecco's modified eagle medium (DMEM). Bacterial growth and biofilm formation in the environment and on the meshes were assessed by changes in optical density, bacterial ATP content, metabolic activity, crystal violet staining, spinning disk confocal microscopy (SDCM), and high-resolution scanning electron microscopy (HR-SEM). The anti-inflammatory effect of the culture medium that was exposed daily to the coated meshes was analyzed by measuring the release of the cytokines IL-6 and IL-10 from LPS-stimulated RAW 264.7 macrophages with appropriate ELISA kits. Additionally, a cytotoxicity assay was performed on Vero epithelial cell lines. We observed that compared with SRV-placebo, the segments coated with SRV-CBG inhibited the bacterial growth of S. aureus in the mesh environment for 9 days by 86 ± 4% and prevented biofilm formation and metabolic activity in the surroundings for 9 days, with respective 70 ± 2% and 95 ± 0.2% reductions. The culture medium that was incubated with the SRV-CBG-coated mesh inhibited LPS-induced secretion of IL-6 and IL-10 from the RAW 264.7 macrophages for up to 6 days without affecting macrophage viability. A partial anti-inflammatory effect was also observed with SRV-placebo. The conditioned culture medium was not toxic to Vero epithelial cells, which had an IC₅₀ of 25 µg/mL for CBG. In conclusion, our data indicate a potential role of coating VICRYL mesh with SRV-CBG in preventing infection and inflammation in the initial period after surgery.

Anti-Bacterial and Anti-Biofilm Activities of Anandamide against the Cariogenic Streptococcus mutans

Streptococcus mutans is a cariogenic bacterium in the oral cavity involved in plaque formation and dental caries. The endocannabinoid anandamide (AEA), a naturally occurring bioactive lipid, has been shown to have anti-bacterial and anti-biofilm activities against Staphylococcus aureus. We aimed here to study its effects on S. mutans viability, biofilm formation and extracellular polysaccharide substance (EPS) production. S. mutans were cultivated in the absence or presence of various concentrations of AEA, and the planktonic growth was followed by changes in optical density (OD) and colony-forming units (CFU). The resulting biofilms were examined by MTT metabolic assay, Crystal Violet (CV) staining, spinning disk confocal microscopy (SDCM) and high-resolution scanning electron microscopy (HR-SEM). The EPS production was determined by Congo Red and fluorescent dextran staining. Membrane potential and membrane permeability were determined by diethyloxacarbocyanine iodide (DiOC2(3)) and SYTO 9/propidium iodide (PI) staining, respectively, using flow cytometry. We observed that AEA was bactericidal to S. mutans at 12.5 µg/mL and prevented biofilm formation at the same concentration. AEA reduced the biofilm thickness and biomass with concomitant reduction in total EPS production, although there was a net increase in EPS per bacterium. Preformed biofilms were significantly affected at 50 µg/mL AEA. We further show that AEA increased the membrane permeability and induced membrane hyperpolarization of these bacteria. AEA caused S. mutans to become elongated at the minimum inhibitory concentration (MIC). Gene expression studies showed a significant increase in the cell division gene ftsZ. The concentrations of AEA needed for the anti-bacterial effects were below the cytotoxic concentration for normal Vero epithelial cells. Altogether, our data show that AEA has anti-bacterial and anti-biofilm activities against S. mutans and may have a potential role in preventing biofilms as a therapeutic measure.

Identification of histone acetyltransferase genes responsible for cannabinoid synthesis in hemp

BACKGROUND

Histone acetyltransferases (HATs) play an important role in plant growth and development, stress response, and regulation of secondary metabolite biosynthesis. Hemp (Cannabis sativa L.) is famous for its high industrial, nutritional, and medicinal value. It contains non-psychoactive cannabinoid cannabidiol (CBD) and cannabinol (CBG), which play important roles as anti-inflammatory and anti-anxiety. At present, the involvement of HATs in the regulation of cannabinoid CBD and CBG synthesis has not been clarified.

METHODS

The members of HAT genes family in hemp were systematically analyzed by bioinformatics analysis. In addition, the expression level of HATs and the level of histone acetylation modification were analyzed based on transcriptome data and protein modification data. Real-time quantitative PCR was used to verify the changes in gene expression levels after inhibitor treatment. The changes of CBD and CBG contents after inhibitor treatment were verified by HPLC-MS analysis.

RESULTS

Here, 11 HAT genes were identified in the hemp genome. Phylogenetic analysis showed that hemp HAT family genes can be divided into six groups. Cannabinoid synthesis genes exhibited spatiotemporal specificity, and histones were acetylated in different inflorescence developmental stages. The expression of cannabinoid synthesis genes was inhibited and the content of CBD and CBG declined by 10% to 55% in the samples treated by HAT inhibitor (PU139). Results indicated that CsHAT genes may regulate cannabinoid synthesis through altering histone acetylation.

CONCLUSIONS

Our study provides genetic information of HATs responsible for cannabinoid synthesis, and offers a new approach for increasing the content of cannabinoid in hemp.

Improved Anti-Biofilm Effect against the Oral Cariogenic Streptococcus mutans by Combined Triclosan/CBD Treatment

Streptococcus mutans is a Gram-positive bacterium highly associated with dental caries, and it has a strong biofilm-forming ability, especially in a sugar-rich environment. Many strategies have been undertaken to prevent dental caries by targeting these bacteria. Recently, we observed that a sustained-release varnish containing triclosan and cannabidiol (CBD) was more efficient than each compound alone in preventing biofilm formation by the fungus Candida albicans, which is frequently involved in oral infections together with S. mutans. It was therefore inquiring to study the effect of this drug combination on S. mutans. We observed that the combined treatment of triclosan and CBD had stronger anti-bacterial and anti-biofilm activity than each compound alone, thus enabling the use of lower concentrations of each drug to achieve the desired effect. The combined drug treatment led to an increase in the SYTO 9^low, propidium iodide (PI)^high bacterial population as analyzed by flow cytometry, indicative for bacteria with disrupted membrane. Both triclosan and CBD induced membrane hyperpolarization, although there was no additive effect on this parameter. HR-SEM images of CBD-treated bacteria show the appearance of elongated and swollen bacteria with several irregular septa structures, and upon combined treatment with triclosan, the bacteria took on a swollen ellipse and sometimes oval morphology. Increased biofilm formation was observed at sub-MIC concentrations of each compound alone, while combining the drugs at these sub-MIC concentrations, the biofilm formation was prevented. The inhibition of biofilm formation was confirmed by CV biomass staining, MTT metabolic activity, HR-SEM and live/dead together with exopolysaccharide (EPS) staining visualized by spinning disk confocal microscopy. Importantly, the concentrations required for the anti-bacterial and anti-biofilm activities toward S. mutans were non-toxic to the normal Vero epithelial cells. In conclusion, the data obtained in this study propose a beneficial role of combined triclosan/CBD treatment for potential protection against dental caries.

Cannabidiol and Cannabigerol Exert Antimicrobial Activity without Compromising Skin Microbiota

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.

Diarylureas: New Promising Small Molecules against Streptococcus mutans for the Treatment of Dental Caries

Dental caries is a biofilm-mediated disease that represents a worldwide oral health issue. Streptococcus mutans has been ascertained as the main cariogenic pathogen responsible for human dental caries, with a high ability to form biofilms, regulated by the quorum sensing. Diarylureas represent a class of organic compounds that show numerous biological activities, including the antimicrobial one. Two small molecules belonging to this class, specifically to diphenylureas, BPU (1,3-bis[3,5-bis(trifluoromethyl)phenyl]urea) and DMTU (1,3-di-m-tolyl-urea), showed interesting results in studies regarding the antimicrobial activity against the cariogenic bacterium S. mutans. Since there are not many antimicrobials used for the prevention and treatment of caries, further studies on these two interesting compounds and other diarylureas against S. mutans may be useful to design new effective agents for the treatment of caries with generally low cytotoxicity.

Comparing proteome changes involved in biofilm formation by Streptococcus mutans after exposure to sucrose and starch

Streptococcus mutans is a main organism of tooth infections including tooth decay and periodontitis. The aim of this study was to assess the influence of sucrose and starch on biofilm formation and proteome profile of S. mutans ATCC 35668 strain. The biofilm formation was assessed by microtiter plating method. Changes in bacterial proteins after exposure to sucrose and starch carbohydrates were analyzed using matrix-assisted laser desorption/ionization mass spectrometry. The biofilm formation of S. mutans was increased to 391.76% in 1% sucrose concentration, 165.76% in 1% starch, and 264.27% in the 0.5% sucrose plus 0.5% starch in comparison to biofilm formation in the media without sugars. The abundance of glutamines, adenylate kinase, and 50S ribosomal protein L29 was increased under exposure to sucrose. Upregulation of lactate utilization protein C, 5-hydroxybenzimidazole synthase BzaA, and 50S ribosomal protein L16 was formed under starch exposure. Ribosome-recycling factor, peptide chain release factor 1, and peptide methionine sulfoxide reductase MsrB were upregulated under exposure to sucrose in combination with starch. The results demonstrated that the carbohydrates increase microbial pathogenicity. In addition, sucrose and starch carbohydrates can induce biofilm formation of S. mutans via various mechanisms such as changes in the expression of special proteins.

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

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.

Phytocannabinoids regulate inflammation in IL-1β-stimulated human gingival fibroblasts

OBJECTIVES

Billions of individuals worldwide suffer from periodontal disease, an inflammatory disease that results in hard-tissue and soft-tissue destruction. A viable therapeutic option to treat periodontal disease may be via cannabinoids that exert immunomodulatory effects, and the endocannabinoid system (ECS) is readily present in periodontal tissues that exhibit cannabinoid type 1 and 2 receptors (CB1R and CB2R). Phytocannabinoids (pCBs), which are a part of a heterogeneous group of molecules acting on cannabinoid receptors (CBR) derived from the cannabis plants, have been attributed to a wide variety of effects including anti-inflammatory activity and some pro-inflammatory effects depending on the cell type. Thus, this study aims to examine the effects of pCBs on primary human gingival fibroblasts (HGFs) in IL-1β stimulated (simulated periodontal disease) HGFs.

MATERIALS AND METHODS

Human gingival fibroblasts (HGFs) obtained from ATCC were cultured per the manufacturer's recommendation. The functional activity of cannabinoid receptors was measured using ACTOne (cAMP)-based CB1R and CB2R assay. The effects of three pCBs (0.1-10 μg/ml or 10^-4.5 -10^-6.5  M) on cell viability were assessed using the CCK-8 cellular dehydrogenase assay. IL-1β (1 ng/ml) was added an hour before the treatment to stimulate inflammation in the HGFs before the addition of cannabinoid ligands. After 24-h incubation, the production of INF-γ, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, and TNF-α was measured using Mesoscale Discovery (MSD) Human Pro-Inflammatory kit. To measure prostaglandin E 2 levels (PGE2), Cisbio HTRF PGE2 assay kit was used per the manufacturer's recommendation to measure after 24-h incubation. The data were analyzed using GraphPad Prism 6.0. The analytes for each group were compared using a one-way ANOVA test with Bonferroni's correction.

RESULTS

Cannabidivarin (CBVN or CBDV) (EC₅₀  = 12 nM) and cannabigerol (CBG) (EC₅₀  = 30 nM) exhibited agonist activity on CB2R with intermediate efficacy. Cannabidiol (CBD) did not exhibit activation of the CB2R, and the CB1R activation was not observed with any of the pCBs. Cytotoxicity results showed that concentrations of 2.50 μg/ml or greater for the pCBs were toxic except for CBVN. Lower concentrations of CBD and CBG (0.1-0.75 μg/ml), and CBVN at 2.50 μg/ml exhibited significant effects on HGF proliferation. In IL-1β-stimulated HGFs, prostaglandin E2 (PGE2) production was significantly suppressed only by CBG and CBVN. CBD and CBG treatment alone did, however, elevate PGE2 production significantly compared to control. IL-1β stimulation resulted in a robust increase in the production of all cytokines tested. Treatment of IL-β-stimulated HGF with the three pCBs (1 μg/ml) significantly reduced INF-ɣ, TNF-α, and IL-2. The significant suppression of IL-4 was seen with CBD and CBVN, while only CBVN exerted suppression of IL-13. The three pCBs significantly increased IL-6, IL-10, and IL-12 levels, while none of the pCBs reduced the expression of IL-8 in IL-1β-stimulated HGF.

CONCLUSION

The effective inhibition of IL-1β-stimulated production of PGE2 and cytokines by the pCB in HGFs suggests that targeting the endocannabinoid system may lead to the development of therapeutic strategies for periodontal therapy. However, each pCB has its unique anti-inflammatory profile, in which certain pro-inflammatory activities are also exhibited. The pCBs alone or in combination may benefit and aid in improving public oral health.

Pharmacological Aspects and Biological Effects of Cannabigerol and Its Synthetic Derivatives

Cannabigerol (CBG) is a cannabinoid from the plant Cannabis sativa that lacks psychotomimetic effects. Its precursor is the acidic form, cannabigerolic acid (CBGA), which is, in turn, a biosynthetic precursor of the compounds cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC). CBGA decarboxylation leads to the formation of neutral cannabinoid CBG, through a chemical reaction catalyzed by heat. On the basis of the growing interest in CBG and with the aim of highlighting scientific information on this phytocannabinoid, we focused the content of this article on its pharmacokinetic and pharmacodynamic characteristics and on its principal pharmacological effects. CBG is metabolized in the liver by the enzyme CYP2J2 to produce hydroxyl and di-oxygenated products. CBG is considered a partial agonist at the CB1 receptor (R) and CB2R, as well as a regulator of endocannabinoid signaling. Potential pharmacological targets for CBG include transient receptor potential (TRP) channels, cyclooxygenase (COX-1 and COX-2) enzymes, cannabinoid, 5-HT1A, and alpha-2 receptors. Pre-clinical findings show that CBG reduces intraocular pressure, possesses antioxidant, anti-inflammatory, and anti-tumoral activities, and has anti-anxiety, neuroprotective, dermatological, and appetite-stimulating effects. Several findings suggest that research on CBG deserves to be deepened, as it could be used, alone or in association, for novel therapeutic approaches for several disorders.

Antibacterial Effects of Phytocannabinoids

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.

Strategies for dispersion of cariogenic biofilms: applications and mechanisms

Bacteria residing within biofilms are more resistant to drugs than planktonic bacteria. They can thus play a significant role in the onset of chronic infections. Dispersion of biofilms is a promising avenue for the treatment of biofilm-associated diseases, such as dental caries. In this review, we summarize strategies for dispersion of cariogenic biofilms, including biofilm environment, signaling pathways, biological therapies, and nanovehicle-based adjuvant strategies. The mechanisms behind these strategies have been discussed from the components of oral biofilm. In the future, these strategies may provide great opportunities for the clinical treatment of dental diseases. Graphical Abstract.

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.

Targeting the Holy Triangle of Quorum Sensing, Biofilm Formation, and Antibiotic Resistance in Pathogenic Bacteria

Chronic and recurrent bacterial infections are frequently associated with the formation of biofilms on biotic or abiotic materials that are composed of mono- or multi-species cultures of bacteria/fungi embedded in an extracellular matrix produced by the microorganisms. Biofilm formation is, among others, regulated by quorum sensing (QS) which is an interbacterial communication system usually composed of two-component systems (TCSs) of secreted autoinducer compounds that activate signal transduction pathways through interaction with their respective receptors. Embedded in the biofilms, the bacteria are protected from environmental stress stimuli, and they often show reduced responses to antibiotics, making it difficult to eradicate the bacterial infection. Besides reduced penetration of antibiotics through the intricate structure of the biofilms, the sessile biofilm-embedded bacteria show reduced metabolic activity making them intrinsically less sensitive to antibiotics. Moreover, they frequently express elevated levels of efflux pumps that extrude antibiotics, thereby reducing their intracellular levels. Some efflux pumps are involved in the secretion of QS compounds and biofilm-related materials, besides being important for removing toxic substances from the bacteria. Some efflux pump inhibitors (EPIs) have been shown to both prevent biofilm formation and sensitize the bacteria to antibiotics, suggesting a relationship between these processes. Additionally, QS inhibitors or quenchers may affect antibiotic susceptibility. Thus, targeting elements that regulate QS and biofilm formation might be a promising approach to combat antibiotic-resistant biofilm-related bacterial infections.

Cannabigerol Effect on Streptococcus mutans Biofilms—A Computational Approach to Confocal Image Analysis

Biofilms are complex bacterial structures in which bacterial cells thrive as a community. Many bacterial species, including pathogens, form biofilms of high complexity and adaptability to a wide range of environmental conditions. One example of these is Streptococcus mutans, a gram-positive bacterium that has been associated with caries. Cannabigerol, a non-psychoactive cannabinoid, has been shown to affect S. mutans biofilms. In order to better characterize the effect of cannabigerol on biofilms of S. mutans, this paper provides a series of computational assays for biofilm analysis, applied on confocal images of S. mutans biofilms treated with cannabigerol. Confocal images are ubiquitous in biofilm analysis—they are often used to visualize the complex structure and molecular composition of biofilm macrocolonies. In this article, we demonstrate how confocal imaging data can be used to reveal more comprehensive insights into biofilm structure and measure specific anti-biofilm effects. This is accomplished by a series of computational assays, each focusing on a different aspect of biofilm structure.

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.

Identification of Antibacterial Components in the Methanol-Phase Extract from Edible Herbaceous Plant Rumex madaio Makino and Their Antibacterial Action Modes

Outbreaks and prevalence of infectious diseases worldwide are some of the major contributors to morbidity and morbidity in humans. Pharmacophageous plants are the best source for searching antibacterial compounds with low toxicity to humans. In this study, we identified, for the first time, antibacterial components and action modes of methanol-phase extract from such one edible herbaceous plant Rumex madaio Makino. The bacteriostatic rate of the extract was 75% against 23 species of common pathogenic bacteria. The extract was further purified using the preparative high-performance liquid chromatography (Prep-HPLC) technique, and five separated componential complexes (CC) were obtained. Among these, the CC 1 significantly increased cell surface hydrophobicity and membrane permeability and decreased membrane fluidity, which damaged cell structure integrity of Gram-positive and -negative pathogens tested. A total of 58 different compounds in the extract were identified using ultra-HPLC and mass spectrometry (UHPLC-MS) techniques. Comparative transcriptomic analyses revealed a number of differentially expressed genes and various changed metabolic pathways mediated by the CC1 action, such as down-regulated carbohydrate transport and/or utilization and energy metabolism in four pathogenic strains tested. Overall, the results in this study demonstrated that the CC1 from R. madaio Makino are promising candidates for antibacterial medicine and human health care products.

Anti-Biofilm Activity of Cannabigerol against Streptococcus mutans

Streptococcus mutans is a common cariogenic bacterium in the oral cavity involved in plaque formation. Previous studies showed that Cannabigerol (CBG) has bacteriostatic and bacteriocidic activity against S. mutans. The aim of the present study was to study its effect on S. mutans biofilm formation and dispersion. S. mutans was cultivated in the presence of CBG, and the resulting biofilms were examined by CV staining, MTT assay, qPCR, biofilm tracer, optical profilometry, and SEM. Gene expression was determined by real-time qPCR, extracellular polysaccharide (EPS) production was determined by Congo Red, and reactive oxygen species (ROS) were determined using DCFH-DA. CBG prevented the biofilm formation of S. mutans shown by reduced biofilm biomass, decreased biofilm thickness, less EPS production, reduced DNA content, diminished metabolic activity, and increased ROS levels. CBG altered the biofilm roughness profile, resulting in a smoother biofilm surface. When treating preformed biofilms, CBG reduced the metabolic activity of S. mutans with a transient effect on the biomass. CBG reduced the expression of various genes involved in essential metabolic pathways related to the cariogenic properties of S. mutans biofilms. Our data show that CBG has anti-biofilm activities against S. mutans and might be a potential drug for preventive treatment of dental caries.