In vitro anticariogenic and antibiofilm activities of toothpastes formulated with essential oils

Screening and selection of essential oils for an intranasal spray against bovine respiratory pathogens based on antimicrobial, antiviral, immunomodulatory, and antibiofilm activities

Introduction

The rise in antibiotic resistant pathogens associated with bovine respiratory disease (BRD) poses a serious challenge, particularly to the beef feedlot industry, as they currently depend on antibiotics to prevent BRD to mitigate the financial burden (approx. $1 billion annual loss) inflicted by BRD-associated high mortality and morbidity in feedlot cattle. Thus, there is an impetus need for the development of antimicrobial alternative strategies against BRD. This study aimed to screen and select candidate essential oils (EOs) for the development of an intranasal EO spray that can inhibit BRD pathogens and promote microbiota-mediated respiratory health.

Methods

The effects of selected EOs (ajowan, cinnamon leaf, citronella, grapefruit, fennel, and thyme) on a bovine nasopharyngeal microbiota culture were evaluated using 16S rRNA gene sequencing. The microbiota culture was enriched by incubating nasopharyngeal swabs obtained from finishing beef heifers in brain heart infusion broth with and without EOs (0.025%, v/v). These EOs were then also evaluated for their immunomodulatory effects on bovine turbinate (BT) cells by analyzing the concentrations of 15 cytokines and chemokines in cell culture after 24 h incubation. The crystal violet assay was done to assess the antibiofilm activity of EOs against Escherichia coli UMN026 strain. Finally, 15 EOs were screened for their antiviral activity against the bovine viral diarrhea virus 1 (BVDV-1) using BT cells and a fluorescence-based method.

Results

Ajowan, fennel, and thyme resulted in a moderate reduction of overall nasopharyngeal microbiota growth with significant alterations of both alpha and beta diversity, and the relative abundance of predominant bacterial families (e.g., increasing Enterobacteriaceae and decreasing Moraxellaceae) compared to the control (p < 0.05). Co-incubation of BT cells with selected EOs resulted in minimal alterations in cytokine and chemokine levels (p > 0.05). Ajowan, thyme, fennel, and cinnamon leaf exhibited antibiofilm activity at concentrations of 0.025 and 0.05%. Reduction of BVDV-1 replication in BT cells was observed with thyme (strong), and ajowan and citronella (moderate) at 0.0125% concentration.

Discussion

Accordingly, ajowan, thyme, fennel, cinnamon leaf, and citronella EOs were selected for further development as an intranasal EO spray to prevent and control of BRD pathogens in feedlot cattle.

Seasonal Variation in Essential Oil Composition and Antioxidant Capacity of Aniba canelilla (Lauraceae): A Reliable Source of 1-Nitro-2-phenylethane

Aniba canelilla (Kunth) Mez essential oil has many biological activities due to its main compound 1-nitro-2-phenylethane (1N2F), followed by methyleugenol, a carcinogenic agent. This study analyzed the influence of seasonality on yields, antioxidant capacity, and 1N2F content of A. canelilla leaf and twig essential oils. Essential oils (EOs) were extracted with hydrodistillation and analyzed with gas chromatography coupled to mass spectrometry and a flame ionization detector. Antioxidant capacity was measured using the free radical scavenging method (DPPH). Chemometric analyses were carried out to verify the influence of climatic factors on the production and composition of EOs. 1-Nitro-2-phenylethane was the major constituent in A. canelilla EOs throughout the seasonal period (68.0-89.9%); methyleugenol was not detected. Essential oil yields and the 1N2F average did not show a statistically significant difference between the dry and rainy seasons in leaves and twigs. Moderate and significant correlations between major compounds and climate factor were observed. The twig oils (36.0 ± 5.9%) a showed greater antioxidant capacity than the leaf oils (20.4 ± 5.0%). The PCA and HCA analyses showed no statistical differences between the oil samples from the dry and rainy seasons. The absence of methyleugenolin in all months of study, described for the first time, makes this specimen a reliable source of 1N2F.

The performance of plant essential oils against lactic acid bacteria and adverse microorganisms in silage production

Plant essential oils have played an important role in the field of antibiotic alternatives because of their efficient bacteriostatic and fungistatic activity. As plant essential oils are widely used, their activity to improve the quality of plant silage has also been explored. This review expounds on the active ingredients of essential oils, their bacteriostatic and fungistatic activity, and mechanisms, as well as discusses the application of plant essential oils in plant silage fermentation, to provide a reference for the development and application of plant essential oils as silage additives in plant silage fermentation feed.

Antimicrobial and mechanical assessment of cellulose-based thermoformable material for invisible dental braces with natural essential oils protecting from biofilm formation

Controlling biofilm formation in the oral cavity during orthodontic treatments is crucial. Therefore, antimicrobial surfaces for invisible dental appliances are of interest to both therapists and patients. Here we present a cellulose-based thermoformable material used for invisible braces that can be loaded with essential oils (EOs) having antibacterial and antifungal properties. We hypothesize that this material can absorb and release EOs, thus providing an antimicrobial effect without compromising the safety and mechanical properties necessary for dental invisible braces. Conventional microbiology and isothermal microcalorimetry analyses revealed that the thermoformable material loaded with essential oils significantly delayed the biofilm formation of oral streptococci (S. mutans and S. mitis) under static conditions (p < 0.05) and while simulating saliva flow (p < 0.05). In addition, cytotoxicity tests (ISO 10993-5), revealed that the loaded material is well tolerated by human gingival fibroblasts. Finally, the loading with antibacterial agents did not significantly alter the mechanical properties and stability of the material (initial force (p = 0.916); initial stress (p = 0.465)). Compared to gold-standard clear aligner materials, this material offers a reliable transmission of forces for orthodontic treatments. Moreover, this approach exhibits the potential for acting as an oral drug delivery platform for multiple compounds.

Antibacterial activity of oregano essential oils against Streptococcus mutans in vitro and analysis of active components

BACKGROUND

Streptococcus mutans (S. mutans) is considered the most relevant bacteria during the transition of the non-pathogenic commensal oral microbial community to plaque biofilms that promote the development of dental caries. Oregano (Origanum vulgare L.), is a universally natural flavoring and its essential oil has been demonstrated to have good antibacterial effects. However, the specific antibacterial mechanism of oregano essential oil (OEO) against S. mutans is still not completely understood.

METHODS

In this work, the composition of two different OEOs was determined by GC‒MS. Disk-diffusion method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined to assess their antimicrobial effect on S. mutans. The inhibition of acid production, hydrophobicity, biofilm formation and real-time PCR for gtfB/C/D, spaP, gbpB, vicR, relA and brpA mRNA expression by S. mutans were assessed to preliminarily investigate the mechanisms of action. Molecular docking was performed to simulate the interactions with the virulence proteins and active constituents. MTT test using immortalized human keratinocytes cells was also performed to investigate cytotoxicity.

RESULTS

Compared with the positive drug Penicillin /streptomycin 100X (DIZ: 34.13 ± 0.85 mm, MIC: 0.78125 μL/mL, MBC: 6.25 μL/mL), the essential oils of Origanum vulgare L. (DIZ: 80 mm, MIC: 0.625μL/mL, MBC:2.5μL/mL) and Origanum heracleoticum L. (DIZ: 39.67 ± 0.81 mm, MIC: 0.625μL/mL, MBC: 1.25μL/mL) could also exhibit similar effects to inhibit the acid production and reduce the hydrophobicity and biofilm formation of S. mutans at 1/2-1MIC concentration. And gene expression of gtfB/C/D, spaP, gbpB, vicR and relA were found to be downregulated. Due to the composition of essential oils from different sources being highly variable, through effective network pharmacology analysis, we found that OEOs contained many effective compounds, like carvacrol and its biosynthetic precursors γ-terpinene and p-cymene, which may directly target several virulence proteins of S. mutans. Besides, no toxic effect was instigated by OEOs at 0.1 μL/mL in the immortalized human keratinocytes cells.

CONCLUSION

The integrated analysis in the present study suggested that OEO might be a potential antibacterial agent for the prevention of dental caries.

Inhibitory Activity of Essential Oils of Mentha spicata and Eucalyptus globulus on Biofilms of Streptococcus mutans in an In Vitro Model

The aim of this study was to evaluate the inhibitory activity of the commercially available essential oils of Mentha spicata (spearmint) and Eucalyptus globulus (eucalyptus) on Streptococcus mutans ATCC 25175 biofilms in vitro, emulating dental plaque conditions. The composition of the essential oils (EOs) was determined using gas chromatography coupled with mass spectrometry (GC-MS), with the main metabolites being Carvone (57.93%) and Limonene (12.91%) for Mentha spicata and 1,8-Cineole (Eucalyptol) (65.83%) for Eucalyptus globulus. The inhibitory activity was evaluated using the methods of agar-well diffusion and colorimetric microdilution. The inhibition halos were 18.3 ± 0.47 mm and 27.0 ± 0.82 mm, and the MICs were 1.8484 mg/mL and 1.9168 mg/mL for the EOs of Mentha spicata and Eucalyptus globulus, respectively. The activity against the biofilms was evaluated on a substrate of bovine enamel pieces using a basal mucin medium (BMM) in anaerobic conditions with daily sucrose exposition cycles in order to emulate oral cavity conditions. The EOs were applied in a concentration of 0.5% in a sterile saline vehicle with 1% polysorbate 20. After 72 h of cultivation, a significant reduction was observed (p < 0.001%) on the biofilm biomass, which was evaluated by its turbidity in suspension and using a count of the recoverable organisms with regards to the control. The effects of the Eos were not significantly distinct from each other. The EOs showed antimicrobial activity against both the Streptococcus mutans planktonic and biofilm cultures. Thus, EOs may have great potential for the development of pharmaceutical and sanitary products for oral health.

Comparative Evaluation of a Commercial Herbal Extract and 0.2% Chlorhexidine Mouthwash on Three Periodontal Facultative Anaerobes: An In Vitro Study

Background

The application of herbal and/or chemical antimicrobial mouthwashes in addition to the mechanical methods of bacteria removal helps reduce the periopathogens and thus increase the periodontal tissues' health. The present study aimed to evaluate the antibacterial effect of Thymex (TMX) syrup on three periodontal facultative anaerobes in vitro and compare it with 0.2% chlorhexidine (CHX) mouthwash.

Methods

In this in vitro experiment, the disc diffusion method was used to measure the inhibitory halo diameter (IhD) of Enterobacter cloacae, Actinomyces viscosus, and Eikenella corrodens. The paper discs containing TMX and CHX were placed on Mueller-Hinton agar media and cultured with the mentioned bacteria. Moreover, a blank disc containing distilled water was used as a control. From each of the three bacterial species, five samples were taken, and after 18 hours of storage in the incubator, the IhDs were measured in millimeters. A one-way ANOVA test and an independent sample t-test were used to compare the mean differences of IhDs between groups. The significance level was considered to be 0.05.

Results

The IhDs ranged between 6.2-8.8 mm and 12.3-34 mm for TMX and CHX, respectively. CHX showed a more inhibitory effect on all three species of bacteria compared to TMX mouthwash (P < 0.001).

Conclusions

Despite the inhibitory effect of TMX on bacterial growth, CHX showed significantly more antibacterial activity than TMX against three studied bacterial species.

Antibiofilm action of Persea americana glycolic extract over Acinetobacter baumannii and absence of toxicity in Galleria mellonella

OBJECTIVES

This study aimed to evaluate the antibiofilm activity and toxicity of the glycolic extract of Persea americana "P. americana" over multidrug-resistant strains of Acinetobacter baumannii "A. baumannii" as alternative therapy to be investigated.

METHODS

A bacterial inoculum of each bacterial strain (4a, 5a, 9a, 12a, ATCC 19606) of A. baumannii was prepared and adjusted by the spectrophotometer. The microdilution broth method was performed to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). P. americana glycolic extracts were obtained of the tree stalk and leaves. The biofilm viability was tested by MTT assay after 5 min exposure. The toxicity of the extracts was tested by invertebrate model Galleria mellonella. The data were analyzed by ANOVA, Tukey test and log-rank method (α=0.05).

RESULTS

The extract showed an inhibitory and bactericidal action over all the tested strains with the lowest MIC value observed for the reference strain (3.12 mg/mL). The extract did not demonstrate toxicity in any of the tested concentrations (12.5, 25 and 50 mg/mL) in Galleria mellonella larvae, with a survival percentage above 80% after 168 h.

CONCLUSIONS

The glycolic extract of P. americana has microbicidal and antibiofilm activity on multidrug-resistant clinical strains of A. baumannii and showed low toxicity for the invertebrate model G. mellonella.

Chemical Composition, Phytotoxic and Antibiofilm Activity of Seven Eucalyptus Species from Tunisia

This study was carried out to characterize the chemical composition of the essential oils from seven Eucalyptus species (E. griffithsii, E. hemiphloia, E. lesouefii, E. longicornis, E. pyriformis, E. viminalis, and E. wandoo), as well as their phytotoxic and antibacterial activities. The essential oils were analyzed by GC/MS and the potential in vitro phytotoxicity was evaluated against germination and radical elongation of Raphanus sativus, Lolium multiflorum, and Sinapis arvensis seeds. The antibiofilm activity was studied against both Gram-negative (Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii) and Gram-positive (Staphylococcus aureus and Listeria monocytogenes) bacteria. The inhibition of biofilm formation and its metabolism was determined at different times. Eucalyptol was the most abundant component in all essential oils studied (ranging from 40.8% for E. lesouefii EO to 73.6% for E. wandoo) except for that of E. pyriformis where it was present but at 15.1%. E. pyriformis was the most active against both germination and radical elongation of S. arvensis. The action of all essential oils proved to be highly effective in inhibiting the bacterial adhesion process of the five strains considered. In light of these results, these essential oils could have potential applications both in the agricultural and health fields.

Origanum vulgare ethanolic extracts as a promising source of compounds with antimicrobial, anti-biofilm, and anti-virulence activity against dental plaque bacteria

Dental caries and periodontal diseases remain a challenge for oral health, especially given the lack of effective and safe treatment options that are currently available. Against the backdrop of an ongoing antimicrobial resistance crisis, a renewed interest in traditional medicinal plants as a potential source of new bioactive compounds has surfaced. In this context, we systematically screened the antimicrobial and anti-biofilm activities of both ethanolic and aqueous extracts of nine Algerian medicinal plants (Artemisia herba alba, Centaurium erythraea, Juglans regia, Laurus nobilis, Matricaria recutita, Mentha pulegium, Mentha piperita, Origanum vulgare and Taraxacum officinale). To evaluate the activity spectrum of the extracts, the screening was carried out against an extensive collection of Streptococcus, Enterococcus and Lacticaseibacillus isolates recovered from dental plaques of Algerian patients. Broad-spectrum antimicrobial and anti-biofilm properties were observed, especially among ethanolic extracts, which marks them as a promising source for bioactive compounds to control oral biofilms. The ethanolic extract of O. vulgare, which showed the most promising effects in the initial screening, was further characterized. We first verified the biocompatibility of this extract using human oral keratinocytes and selected a range of non-cytotoxic concentrations (0.195-0.781 mg/ml) to further validate its anti-biofilm and anti-virulence potential. At these concentrations, the extract not only prevented biofilm formation (10.04 ± 0.75-87.91 ± 9.08% of reduction) of most dental plaque isolates on a polystyrene surface, but also significantly reduced their adherence to hydroxyapatite (34.58 ± 9.09-62.77 ± 0.95%). Moreover, the extract showed curative potential against mature biofilms grown under conditions mimicking the oral niche. In addition to its anti-biofilm properties, we observed an inhibition of glucosyltransferase activity, a reduction in acidogenesis and a downregulation in the expression of multiple virulence-associated genes for extract-treated samples. Since anti-virulence properties are more robust to the development of resistance, they provide an attractive complementation to the antimicrobial activities of the extract. Thymol was identified as an important active compound of the extract using GC-MS analysis, but synergy with other compounds was also detected, suggesting a potential advantage of using the whole extract over purified thymol. Further research into the bioactive compounds of the O. vulgare ethanolic extract could yield novel products to fight dental caries.

Efficacy of Antimicrobial Agents in Dentifrices: A Systematic Review

The aim of this systematic review was to verify if the presence of different antimicrobial agents in dentifrices is effective in reducing the number of microorganisms for disease prevention. This review followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines and was registered with the Open Science Framework (OSF). A search was conducted in the PubMed, Embase, Scopus, and Web of Science databases. Two independent authors reviewed the titles and abstracts according to the inclusion criteria, which comprised in vitro studies published in English that evaluated the efficacy of antimicrobial agents in dentifrices and their antimicrobial activity. A total of 527 articles were found. Of these, 334 were included for reading of the title and abstract, and 69 were selected for reading in full. In the end, 39 articles remained in this review. Triclosan, sodium fluoride, and sodium monofluorophosphate were the most commonly used chemical antimicrobial agents. Among the herbal agents, miswak extract and neem extract were the most commonly used. The presence of antimicrobial agents in dentifrice formulations can promote the reduction of the number of microorganisms involved in oral diseases, but with variations in their effectiveness, depending on the agent used and the microorganism evaluated.

Chemical vs. natural toothpaste: which formulas for which properties? A scoping review

Introduction

The proliferation of the oral care industry has made it more challenging for shoppers to zero in on the best possible toothpaste for their preventative requirements. It also makes the toothpaste’s various components safer.

Objective

The researchers set out to evaluate the state of information about the biological properties and cytotoxicity of adult toothpaste so that they might make some informed recommendations.

Methods

A scoping review of research published between 2015 and 2020 according to PRISMA guidelines was performed.

Results

In vitro clinical trials account for 44% of the papers, in vivo clinical trials for 25%, systematic reviews for 19%, and metaanalyses for 12%. They have active chemical components that have been shown to be antimicrobial, anti-inflammatory, or desensitizing. Herbal toothpaste has these characteristics and is very secure to use. Toothpaste with sodium lauryl sulfate has been found to be harmful.

Conclusions

Scientists have investigated the biological effects of a wide range of chemically active compounds and plant extracts. Herbal toothpaste, it has been discovered, is both efficient and secure. Companies making toothpaste should be required to clearly label the product’s qualities, active ingredients, and potentially harmful ingredients on the packaging.

Development and Physicochemical Characterization of Eugenia brejoensis Essential Oil-Doped Dental Adhesives with Antimicrobial Action towards Streptococcus mutans

Dental caries is a multifactorial, biofilm-dependent infectious disease that develops when detrimental changes occur in the oral cavity microenvironment. The antimicrobial and antivirulence properties of the essential oil obtained from the leaves of Eugenia brejoensis Mazine (EBEO) have been reported against Gram-positive and Gram-negative bacteria. Herein, the antimicrobial action of EBEO towards Streptococcus mutans is reported, along with the development and characterization of dental adhesives doped with. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of EBEO were determined against S. mutans, while its toxicity was analyze using Tenebrio molitor larvae. EBEO (MIC and 10×MIC) was incorporated into the Ambar Advanced Polymerization System® (Ambar APS), a two-step total-etch adhesive system (FGM Dental Group), and the antibiofilm action was evaluated. The reflective strength, modulus of elasticity, degree of conversion, and maximum rate of polymerization of each adhesive were also determined. The MIC and MBC values of EBEO against S. mutans were 62.5 µg/mL. The tested concentrations of EBEO were non-toxic to T. molitor larvae. The formation of S. mutans biofilms was significantly inhibited by EBEO and EBEO-coated resin discs (p < 0.05). Importantly, EBEO incorporation did not affect the mechanical and physicochemical properties in relation to oil-free adhesive version. EBEO showed strong antibacterial and antibiofilm activity against S. mutans, no toxicity effect against T. molitor larvae, and did not jeopardize the physical-chemical properties tested.

Cinnamomum: The New Therapeutic Agents for Inhibition of Bacterial and Fungal Biofilm-Associated Infection

Due to the potent antibacterial properties of Cinnamomum and its derivatives, particularly cinnamaldehyde, recent studies have used these compounds to inhibit the growth of the most prevalent bacterial and fungal biofilms. By inhibiting flagella protein synthesis and swarming motility, Cinnamomum could suppress bacterial attachment, colonization, and biofilm formation in an early stage. Furthermore, by downregulation of Cyclic di‐guanosine monophosphate (c‐di‐GMP), biofilm-related genes, and quorum sensing, this compound suppresses intercellular adherence and accumulation of bacterial cells in biofilm and inhibits important bacterial virulence factors. In addition, Cinnamomum could lead to preformed biofilm elimination by enhancing membrane permeability and the disruption of membrane integrity. Moreover, this substance suppresses the Candida species adherence to the oral epithelial cells, leading to the cell wall deformities, damage, and leakages of intracellular material that may contribute to the established Candida’s biofilm elimination. Therefore, by inhibiting biofilm maturation and destroying the external structure of biofilm, Cinnamomum could boost antibiotic treatment success in combination therapy. However, Cinnamomum has several disadvantages, such as poor solubility in aqueous solution, instability, and volatility; thus, the use of different drug-delivery systems may resolve these limitations and should be further considered in future investigations. Overall, Cinnamomum could be a promising agent for inhibiting microbial biofilm-associated infection and could be used as a catheter and other medical materials surface coatings to suppress biofilm formation. Nonetheless, further in vitro toxicology analysis and animal experiments are required to confirm the reported molecular antibiofilm effect of Cinnamomum and its derivative components against microbial biofilm.

Microbial approaches for the assessment of toothpaste efficacy against oral species: A method comparison

Antibacterial properties of toothpastes enable chemical plaque control in limited‐access tooth regions that are mechanically not sufficiently reached by toothbrushes. Therefore, this study aimed to compare different microbial methods to assess antimicrobial toothpaste properties and evaluate different toothpastes in terms of their antibacterial efficacy against different oral microorganisms in an in vitro setting. Six toothpaste suspensions with varying antibacterial supplements were applied to a multispecies biofilm model (Actinomyces oris, Candida albicans, Fusobacterium nucleatum, Streptococcus oralis, and Streptococcus mutans) as well as to each microorganism. A culture method was used to assess the anti‐biofilm effects and two different agar diffusion assays were performed for testing the antimicrobial effect on each microorganism. The measurements of the culture and diffusion analyses were statistically normalized and compared and toothpastes were ranked according to their antimicrobial efficacy. The results of both agar diffusion assays showed a high correlation across all tested species (Spearman correlation coefficients ρ_s > 0.95). The results of the multispecies biofilm model, however, substantially differed in its assessment of antibacterial properties (ρ_s ranging from 0.22 to 0.87) compared to the results of both diffusion assays. Toothpastes with amine fluoride (with and without stannous fluoride), and toothpastes with triclosan resulted in the highest antimicrobial efficacy. Activated carbon supplements in toothpastes were comparable in their antimicrobial action to the negative control NaCl. The appropriate selection of a broad range of oral microorganisms seems crucial when testing the chemical impact of toothpaste and toothpaste supplements.

Photodynamic Therapy with Natural Photosensitizers in the Management of Periodontal Disease Induced in Rats

This study aims to investigate the effect of new natural photosensitizers (PS) (based on oregano essential oil, curcuma extract, and arnica oil) through in vitro cytotoxicity and biological tests in rat-induced periodontal disease, treated with photodynamic therapy (aPDT). The cytotoxicity of PS was performed on human dental pulp mesenchymal stem cells (dMSCs) and human keratinocyte (HaCaT) cell lines. Periodontal disease was induced by ligation of the first mandibular molar of 25 rats, which were divided into 5 groups: control group, periodontitis group, Curcuma and aPDT-treated group, oregano and aPDT-treated group, and aPDT group. The animals were euthanized after 4 weeks of study. Computed tomography imaging has been used to evaluate alveolar bone loss. Hematological and histological evaluation showed a greater magnitude of the inflammatory response and severe destruction of the periodontal ligaments in the untreated group.. For the group with the induced periodontitis and treated with natural photosensitizers, the aPDT improved the results; this therapy could be an important adjuvant treatment. The obtained results of these preliminary studies encourage us to continue the research of periodontitis treated with natural photosensitizers activated by photodynamic therapy.

Formulation of an Origanum vulgare based dental gel with antimicrobial activity

OBJECTIVES

This study aims to formulate a new Origanum vulgare anti-caries dental gel with high antimicrobial activity.

METHODS

O. vulgare essential oil was extracted using hydro-distillation, ethanol extraction, gas chromatography/mass spectrometry, and high-performance liquid chromatography methods. Antimicrobial activity of the produced gels with oregano oil and extract was determined through the disco-diffusion method. The effectiveness of O. vulgare essential oil was tested in vitro for Streptococcus mutans biofilm using colorimetric analysis.

RESULTS

O. vulgare essential oil inhibited the growth of S. mutans biofilm by 98% compared with unexposed control bacteria (p <0.05). Five samples of anti-caries gel (ACDG1, ACDG2, ACDG3, ACDG4, ACDG5) were formulated using the obtained oregano essential oil and extract. Based on the microbiological study results, the ACDG1 and ACDG3 gel samples exhibited high antimicrobial activity against the gram-positive bacterial strains of Staphylococcus aureus and Bacillus subtilis and the yeast fungus Candida albicans and moderate antimicrobial activity against the gram-negative strains of Escherichia coli and Pseudomonas aeruginosa.

CONCLUSION

Based on the results of this study, the ACDG3 sample may be considered an anti-caries gel owing to its high antimicrobial activity. This sample has good organoleptic properties compared to other samples, produces relatively high antimicrobial activity, and guards against cariogenic biofilms of S. mutans.

Effectiveness of Oil-Based Denture Dentifrices-Organoleptic Characteristics, Physicochemical Properties and Antimicrobial Action

Denture dentifrices must be effective and not deleterious to prosthetic devices. This study formulated and evaluated dentifrices based on oils of Copaifera officinalis, Eucalyptus citriodora, Melaleuca alternifolia, Pinus strobus, and Ricinus communis. Organoleptic characteristics (appearance, color, odor, taste), physicochemical properties (pH, density, consistency, rheological, abrasiveness, weight loss, and surface roughness) and antimicrobial (Hole-Plate Diffusion–HPD)/anti-biofilm (Colony Forming Units–CFU) action against Staphylococcus aureus, Streptococcus mutans, and Candida albicans were evaluated. Formulations were compared with water (negative control) and a commercial dentifrice (positive control). The data were analyzed by Kruskal-Wallis and Dunn tests (α = 0.05). The organoleptic and physicochemical properties were adequate. All dentifrices promoted weight losses, with high values for C. officinalis and R. communis, and an increase in surface roughness, without differing from each other. For antimicrobial action, C. officinalis and E. citriodora dentifrices were similar to positive control showing effectiveness against S. mutans and C. albicans and no dentifrice was effective against S. aureus; regarding the anti-biofilm action, the dentifrices were not effective, showing higher CFU counts than positive control for all microorganisms. The dentifrices presented satisfactory properties; and, although they showed antimicrobial action when evaluated by HPD, they showed no effective anti-biofilm action on multispecies biofilm.

Antimicrobials from Medicinal Plants: An Emergent Strategy to Control Oral Biofilms

Oral microbial biofilms, directly related to oral diseases, particularly caries and periodontitis, exhibit virulence factors that include acidification of the oral microenvironment and the formation of biofilm enriched with exopolysaccharides, characteristics and common mechanisms that, ultimately, justify the increase in antibiotics resistance. In this line, the search for natural products, mainly obtained through plants, and derived compounds with bioactive potential, endorse unique biological properties in the prevention of colonization, adhesion, and growth of oral bacteria. The present review aims to provide a critical and comprehensive view of the in vitro antibiofilm activity of various medicinal plants, revealing numerous species with antimicrobial properties, among which, twenty-four with biofilm inhibition/reduction percentages greater than 95%. In particular, the essential oils of Cymbopogon citratus (DC.) Stapf and Lippia alba (Mill.) seem to be the most promising in fighting microbial biofilm in Streptococcus mutans, given their high capacity to reduce biofilm at low concentrations.