The antimicrobial effect of Rosmarinus officinalis extracts on oral initial adhesion ex vivo

Medicinal Plants Against Dental Caries: Research and Application of Their Antibacterial Properties

Dental caries remains one of the most widespread global health concerns, significantly affecting both oral and overall health. Conventional treatments typically rely on chemical-based products which, although effective, are often associated with undesirable side effects such as tooth staining, altered taste, and the development of antimicrobial resistance. As a response, plant-based natural alternatives have gained attention as promising strategies for the prevention and management of dental caries. This review highlights the antibacterial properties of medicinal plants and their potential applications in dentistry, with a particular focus on their activity against a broad range of bacteria and microorganisms involved in oral diseases. Numerous plant extracts and bioactive compounds-including polyphenols, flavonoids, and essential oils-have demonstrated antimicrobial, anti-inflammatory, and antioxidant properties that contribute to maintaining oral health. Although in vitro and in vivo studies support their therapeutic potential, clinical trials assessing long-term efficacy and safety remain scarce. Future research should prioritize the standardization of extraction methods, dosage, and formulations to facilitate the integration of these natural alternatives into conventional dental care practices.

Plant polyphenols, terpenes, and terpenoids in oral health

Introduction

Herbal products are increasingly being used for their potential to promote oral health. Phytochemicals can act as scavengers of reactive or toxic chemicals, selective growth factors for beneficial oral bacteria, fermentation substrates for beneficial oral bacteria, and selective inhibitors of harmful oral microflora. Plant-derived secondary metabolites encompass a variety of natural products, including alkaloids, polyphenols (including flavonoids and tannins), terpenes, terpenoids, steroids, saponins, quinones, coumarins, glycosides, and carotenoids.

Objectives

This review explores medicinal plant-based products for preventing and treating oral diseases, offering updated insights into the scientific basis for using herbs as active ingredients in oral health care. Hence, we focused on: (1) phenolic compounds, the most abundant and common phytochemicals and (2) terpenes and terpenoids, the most diverse and widely distributed group in the plant kingdom.

Methods

Several databases were queried to acquire peer-reviewed studies focusing on the major phytochemical compositions - phenolic compounds, terpenes, and terpenoids - and their oral health benefits.

Results

The review lists numerous medicinal herbs in various forms and applications for treating dental caries, gingivitis, and periodontitis.

Conclusion

This review explores the evidence supporting the oral health-promoting effects of specific constituents in herbs with the potential for incorporation into pharmaceutical formulations.

Antibiotic-potentiating efficacy of Rosmarinus officinalis L. to combat planktonic cells, biofilms, and efflux pump activities of extensively drug-resistant Acinetobacter baumannii clinical strains

Introduction

This research aimed to examine the action of commercial antibiotics against extensively drug-resistant (XDR) A. baumannii clinical strains when combined with Rosmarinus officinalis extracts.

Methods

Agar well diffusion and broth microdilution were used to screen the antibacterial activity of crude ethanol extract and its fractions (hexane, intermediate, ethyl acetate, and water). The interactions between the extracts and antibiotics (gentamicin, tetracycline, cefepime, and ciprofloxacin) were evaluated by checkerboard assay. The anti-biofilm and efflux pump inhibition activities were determined by the microtiter plate method and dye accumulation assay using flow cytometry, respectively. The potential phytochemicals that contribute to the antibacterial effects of R. officinalis were identified using the liquid chromatography-mass spectrometry (LC-MS).

Results

R. officinalis crude extract (CE) demonstrated the best antibacterial activity with MIC values ranging from 300 to 600 μg/mL. The combination of CE and tetracycline exhibited the highest overall synergistic effect. This combination hindered biofilm formation ranging from 21.4% to 57.31% and caused a significant increase (up to 14%) in the fluorescence intensity in 75% of the studied strains. The LC-MS analysis of CE exhibited eleven compounds in which rosmarinic acid (55.53%) was the most abundant phenolic compound followed by cirsimaritin (11.46%), and p-coumaroyl hexoside acid (10.5%).

Discussion

Overall, this is the first direct report that demonstrated the efficacy of R. officinalis when applied with conventional antibiotics on biofilm formation and efflux pump activity in XDR A. baumannii clinical strains.

Antibiofilm potential of plant extracts: inhibiting oral microorganisms and Streptococcus mutans

Introduction

A range of disinfectant mouthwashes are available for oral hygiene. The gold standard is Chlorhexidine digluconate (CHX), which, like other available products, cannot be used without side effects in the long term. However, in recent years, therapy with herbal products, often considered antiquated, has regained considerable interest. Therefore, the search for plant compounds as an alternative to existing oral disinfectants is meaningful.

Methods

In this study, eleven Mediterranean plant extracts were tested for their antimicrobial effect in vitro. Methanol extracts of the following plants were produced by the pharmaceutical faculty of the University of Athens: Mentha aquatica, Mentha longifolia, Sideritis euboea, Sideritis syriaca, Stachys spinosa, Satureja parnassica, Satureja thymbra, Lavandula stoechas, Achillea taygetea, Phlomis cretica, and Vaccinium myrtillus. The extracts were dissolved for microdilution experiments at concentrations ranging from 10 to 0.019 mg/ml. The oral pathogens tested were Streptococcus mutans, Streptococcus oralis, Streptococcus sobrinus, Prevotella intermedia, Fusobacterium nucleatum, Parvimonas micra, Porphyromonas gingivalis, and Candida albicans. Enterococcus faecalis, Staphylococcus aureus, and Escherichia coli were used as references.

Results

All extracts, except the methanol extract of V. myrtillus, showed an antibacterial effect at concentrations ranging from 10 to 0.15 mg/ml. None of the extracts exhibited a significant antifungal effect. In general, the anaerobic pathogens could be inhibited and killed at lower concentrations compared to the aerobic pathogens. S. oralis also showed good susceptibility to the extracts. Additionally, the extracts' ability to inhibit biofilm formation by S. mutans was tested. L. stoechas at a concentration of 0.3 mg/ml showed a moderate inhibitory effect. The extracts of L. stoechas, S. thymbra, S. parnassica, and the methanol extract of V. myrtillus were effective at concentrations up to 1.25 mg/ml. P. cretica was able to inhibit and kill S. mutans at a concentration of 0.6 mg/ml, but its effectiveness in biofilm inhibition significantly decreased at 2.5 mg/ml.

Discussion

The study's hypothesis that all extracts would exhibit an antimicrobial effect was thus confirmed.

Evaluation of early bacterial adhesion on CAD/CAM dental materials: an in situ study

The aim of this research was to determine if there are differences in early bacterial adhesion among CAD/CAM dental materials after 24 h exposure in the oral environment. One hundred twenty specimens were prepared according to the manufacturer's recommendations and divided into six groups: RBC (resin-based composite), PMMA (polymethyl methacrylate), PEEK (polyether ether ketone), ZP (zirconia polished), ZG (zirconia glazed), and cobalt-chromium alloy (CoCr alloy). Twenty healthy participants were instructed to carry an intraoral device with six specimens, one per group, for 24 h. Thereafter, real-time polymerase chain reaction (qPCR) and scanning electron microscopy (SEM) analyses enabled quantification and 2D view of biofilm formed on the specimens' surfaces. Kruskal-Wallis test and Dunn's post hoc analysis were used for inter-group comparison and data were presented as median (minimum-maximum). RBC specimens accumulated less bacteria, in comparison with ZG (p = 0.017) and PEEK specimens (p = 0.030), that dominated with the highest amount of adhered bacterial biofilm. PMMA, CoCr, and ZP specimens adhered more bacteria than RBC (p > 0.05), and less than ZG (p > 0.05) and PEEK (p > 0.05). The bacterial number varied considerably among participants. The obtained results enable a closer view into the susceptibility of CAD/CAM materials to microorganisms during the presence in the oral environment, which can be beneficial for a proper selection of these materials for a variety of dental restorations.

Exploring the therapeutic potential of medicinal plants and their active principles in dental care: A comprehensive review

Since the human population realized how important it was to maintain overall health and the weight of disease, they have been looking for therapeutic qualities in natural environments. The use of plants having medicinal qualities for the treatment and prevention of illnesses that may have an impact on general health is known as herbal medicine. There has been a noticeable increase in interest lately in the combination of synthetic contemporary medications and traditional herbal remedies. About 80 % of people rely on it for healthcare, particularly in developing nations. One important aspect of overall health is said to be oral healthcare. The World Health Organization views oral health as a crucial component of overall health and well-being. Because they are more readily available, less expensive, and have fewer adverse effects than pharmaceutical treatments, using natural medicines to treat pathologic oro-dental disorders can make sense. The current evaluation of the literature sought to investigate the range and scope of the use of herbal products and their secondary metabolites in maintaining oral health, encompassing several oral healthcare domains such as halitosis, gingivitis, periodontitis, and other oral disorders. Therefore, there are many herbs discussed in this work and their mechanism in the treatment and improvement of many oral ailments. Besides, compounds that are useful in oral treatment with their natural sources and the cases where they can be used. To prevent any possible side effects or drug interactions, a doctor's consultation is necessary before using dental medicine. Although herbal therapy is safe and with minimum side effects, it is also strongly advised to do a more thorough preclinical and clinical evaluation before using herbal medicines officially.

Plant-Derived Compounds: A Promising Tool for Dental Caries Prevention

There is a growing shift from the use of conventional pharmaceutical oral care products to the use of herbal extracts and traditional remedies in dental caries prevention. This is attributed to the potential environmental and health implications of contemporary oral products. This comprehensive review aims at the analysis of plant-derived compounds as preventive modalities in dental caries research. It focuses on data collected from 2019 until recently, trying to emphasize current trends in this topic. The research findings suggest that several plant-derived compounds, either aqueous or ethanolic, exhibit notable antibacterial effects against Streptococcus mutans and other bacteria related to dental caries, with some extracts demonstrating an efficacy comparable to that of chlorhexidine. Furthermore, in vivo studies using plant-derived compounds incorporated in food derivatives, such as lollipops, have shown promising results by significantly reducing Streptococcus mutans in high-risk caries children. In vitro studies on plant-derived compounds have revealed bactericidal and bacteriostatic activity against S. mutans, suggesting their potential use as dental caries preventive agents. Medicinal plants, plant-derived phytochemicals, essential oils, and other food compounds have exhibited promising antimicrobial activity against oral pathogens, either by their anti-adhesion activity, the inhibition of extracellular microbial enzymes, or their direct action on microbial species and acid production. However, further research is needed to assess their antimicrobial activity and to evaluate the cytotoxicity and safety profiles of these plant-derived compounds before their widespread clinical use can be recommended.

Rosemary - its biologically active compounds and their pharmacological effects

Rosemary - its biologically active compounds and their pharmacological effects Rosemary (Rosmarinus officinalis L.) has been used since ancient times for medicinal, cultic, and magic purposes. With the stress and diseases, it is increasingly popular today for many uses in both pharmacy and aromatherapy, as a spice in the kitchen and as a preservative. This plant has many interesting compounds (e.g. rosmarinic and carnosic acid, carnosol), which show a considerable amount of positive pharmacological effects.

Optimizing the use of low-frequency ultrasound for bacterial detachment of in vivo biofilms in dental research-a methodological study

OBJECTIVES

Low-frequency, low-intensity ultrasound is commonly utilized in various dental research fields to remove biofilms from surfaces, but no clear recommendation exists in dental studies so far. Therefore, this study aims to optimize the sonication procedure for the dental field to efficiently detach bacteria while preserving viability.

MATERIALS AND METHODS

Initial biofilm was formed in vivo on bovine enamel slabs (n = 6) which were worn by four healthy participants for 4 h and 24 h. The enamel slabs covered with biofilm were then ultrasonicated ex vivo for various time periods (0, 1, 2, 4, 6 min). Colony-forming units were determined for quantification, and bacteria were identified using MALDI-TOF. Scanning electron microscopic images were taken to also examine the efficiency of ultrasonications for different time periods.

RESULTS

Ultrasonication for 1 min resulted in the highest bacterial counts, with at least 4.5-fold number compared to the non-sonicated control (p < 0.05). Most bacteria were detached within the first 2 min of sonication, but there were still bacteria detached afterwards, although significantly fewer (p < 0.0001). The highest bacterial diversity was observed after 1 and 2 min of sonication (p < 0.03). Longer sonication periods negatively affected bacterial counts of anaerobes, Gram-negative bacteria, and bacilli. Scanning electron microscopic images demonstrated the ability of ultrasound to desorb microorganisms, as well as revealing cell damage and remaining bacteria.

CONCLUSIONS

With the use of low-frequency, low-intensity ultrasound, significantly higher bacterial counts and diversity can be reached. A shorter sonication time of 1 min shows the best results overall.

CLINICAL RELEVANCE

This standardization is recommended to study initial oral biofilms aged up to 24 h to maximize the outcome of experiments and lead to better comparability of studies.

Overview of strategies to improve the antibacterial property of dental implants

The increasing number of peri-implant diseases and the unsatisfactory results of conventional treatment are causing great concern to patients and medical staff. The effective removal of plaque which is one of the key causes of peri-implant disease from the surface of implants has become one of the main problems to be solved urgently in the field of peri-implant disease prevention and treatment. In recent years, with the advancement of materials science and pharmacology, a lot of research has been conducted to enhance the implant antimicrobial properties, including the addition of antimicrobial coatings on the implant surface, the adjustment of implant surface topography, and the development of new implant materials, and significant progress has been made in various aspects. Antimicrobial materials have shown promising applications in the prevention of peri-implant diseases, but meanwhile, there are some shortcomings, which leads to the lack of clinical widespread use of antimicrobial materials. This paper summarizes the research on antimicrobial materials applied to implants in recent years and presents an outlook on the future development.

Reduction of oral pathogens and oxidative damage in the CAL 27 cell line by Rosmarinus officinalis L. and Taraxacum officinale Web. Extracts

ETHNOPHARMACOLOGICAL RELEVANCE

Dandelion (Taraxacum officinale Web.) and rosemary (Rosmarinus officinalis L.) are treasured botanicals with a long usage history in traditional herbal practices worldwide. Dandelion was used to treat kidney, spleen, and liver disease, as well as cardiovascular disease, diabetes, and bacterial infections, whereas rosemary was used to treat pain, spasms, and to improve blood circulation.

AIM OF THE STUDY

The aim of this study was to determine the influence of rosemary and dandelion leaves aqueous extracts on the human tongue epithelial carcinoma cell line (CAL 27) at the level of interaction between oral microbiota and tongue epithelial cells, genomic damage, and H₂O₂ - induced oxidative damage protection.

MATERIALS AND METHODS

The polyphenolic composition of the extracts was determined by spectrophotometric and HPLC analyses. After extract treatment, cytotoxic impact and ROS generation in CAL 27 cells were measured using the MTT assay and the 2',7'-dichlorofluorescein-diacetate (DCFH-DA) assay, respectively. Microdilutions were applied to investigate the antimicrobial and adhesive properties against representatives of the oral microbiota. The single-cell gel electrophoresis (comet assay) and cytokinesis-blocked micronucleus cytome assay (CBMN cyt) were used to detect induced genomic damages.

RESULTS

Both extracts increased the adhesion of the lactic acid bacteria L. plantarum but decreased the adhesion of the bacterial pathogens S. enterica serovar Typhimurium LT21 and E. coli K-12 MG1655 adhesion onto CAL 27 cells. 1 h treatment with 5x concentrated dandelion extract and 1x, 2.5x, and 5x of rosemary extract caused an increase in comet tail intensity. CBMN cyt results demonstrated a significant increase in micronucleus formation even at concentrations several times lower than the usual bioactive compound concentrations found in a cup of beverage, with higher concentrations also inducing cell apoptosis and necrosis. Rosemary extract showed a protective effect against H₂O₂ - induced oxidative damage by decreasing the apoptotic cell number, probably preventing mutations leading to tumor aggressiveness, invasion, and metastasis.

CONCLUSIONS

Both tested extracts demonstrated their usefulness in maintaining good oral bacteria balance and their protective capability as powerful antitumor agents by causing a protective apoptotic effect in tumor cell line already at the dosage of an average daily cup.

The oral microbiota is a reservoir for antimicrobial resistance: resistome and phenotypic resistance characteristics of oral biofilm in health, caries, and periodontitis

BACKGROUND

Antimicrobial resistance (AMR) is an ever-growing threat to modern medicine and, according to the latest reports, it causes nearly twice as many deaths globally as AIDS or malaria. Elucidating reservoirs and dissemination routes of antimicrobial resistance genes (ARGs) are essential in fighting AMR. Human commensals represent an important reservoir, which is underexplored for the oral microbiota. Here, we set out to investigate the resistome and phenotypic resistance of oral biofilm microbiota from 179 orally healthy (H), caries active (C), and periodontally diseased (P) individuals (TRN: DRKS00013119, Registration date: 22.10.2022). The samples were analysed using shotgun metagenomic sequencing combined, for the first time, with culture technique. A selection of 997 isolates was tested for resistance to relevant antibiotics.

RESULTS

The shotgun metagenomics sequencing resulted in 2,069,295,923 reads classified into 4856 species-level OTUs. PERMANOVA analysis of beta-diversity revealed significant differences between the groups regarding their microbiota composition and their ARG profile. The samples were clustered into three ecotypes based on their microbial composition. The bacterial composition of H and C samples greatly overlapped and was based on ecotypes 1 and 2 whereas ecotype 3 was only detected in periodontitis. We found 64 ARGs conveying resistance to 36 antibiotics, particularly to tetracycline, macrolide-lincosamide-streptogramin, and beta-lactam antibiotics, and a correspondingly high prevalence of phenotypic resistance. Based on the microbiota composition, these ARGs cluster in different resistotypes, and a higher prevalence is found in healthy and caries active than in periodontally diseased individuals. There was a significant association between the resistotypes and the ecotypes. Although numerous associations were found between specific antibiotic resistance and bacterial taxa, only a few taxa showed matching associations with both genotypic and phenotypic analyses.

CONCLUSIONS

Our findings show the importance of the oral microbiota from different niches within the oral cavity as a reservoir for antibiotic resistance. Additionally, the present study showed the need for using more than one method to reveal antibiotic resistance within the total oral biofilm, as a clear mismatch between the shotgun metagenomics method and the phenotypic resistance characterization was shown.