Effect of cinnamon (Cinnamomum verum) bark essential oil on the halitosis-associated bacterium Solobacterium moorei and in vitro cytotoxicity

Antibacterial Effects of Ramulus mori Oligosaccharides against Streptococcus mutans

Ramulus mori has been widely used in traditional Chinese medicine because of its physiological activities, including antibacterial, anti-inflammatory, and antioxidant activities. Antimicrobial properties of Ramulus mori extract have been well described. However, no information is available regarding on Ramulus mori oligosaccharides (RMOS). The aim of this study was to investigate the effects of RMOS on the growth and virulence properties of the cariogenic bacterium Streptococcus mutans. The effects of RMOS on the biofilm structure and virulence gene expression of S. mutans were also evaluated, and the results were compared with the effects of commercial prebiotic galactooligosaccharides. RMOS were found to have an antibacterial effect against S. mutans, resulting in significant reductions in acid production, lactate dehydrogenase activity, adhesion, insoluble extracellular polysaccharide production, glucosyltransferase activity, and biofilm formation in a dose-dependent manner. Moreover, the biofilm structure was visibly damaged. A quantitative real-time PCR assay revealed downregulation of virulence gene-regulated acid production, polysaccharide production, adhesion, biofilm formation, and quorum sensing. These findings suggest that RMOS may be a promising natural product for the prevention of dental caries.

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.

Oral Microbiome: Getting to Know and Befriend Neighbors, a Biological Approach

The oral microbiome, forming a biofilm that covers the oral structures, contains a high number of microorganisms. Biofilm formation starts from the salivary pellicle that allows bacterial adhesion–colonization–proliferation, co-aggregation and biofilm maturation in a complex microbial community. There is a constant bidirectional crosstalk between human host and its oral microbiome. The paper presents the fundamentals regarding the oral microbiome and its relationship to modulator factors, oral and systemic health. The modern studies of oral microorganisms and relationships with the host benefits are based on genomics, transcriptomics, proteomics and metabolomics. Pharmaceuticals such as antimicrobials, prebiotics, probiotics, surface active or abrasive agents and plant-derived ingredients may influence the oral microbiome. Many studies found associations between oral dysbiosis and systemic disorders, including autoimmune diseases, cardiovascular, diabetes, cancers and neurodegenerative disorders. We outline the general and individual factors influencing the host–microbial balance and the possibility to use the analysis of the oral microbiome in prevention, diagnosis and treatment in personalized medicine. Future therapies should take in account the restoration of the normal symbiotic relation with the oral microbiome.

Novel cinnamon-laden nanofibers as a potential antifungal coating for poly(methyl methacrylate) denture base materials

OBJECTIVES

To modify the surface of denture base material by coating it with cinnamon-laden nanofibers to reduce Candida albicans (C. albicans) adhesion and/or proliferation.

MATERIALS AND METHODS

Heat-cured poly(methyl methacrylate) (PMMA) specimens were processed and coated, or not, with cinnamon-laden polymeric nanofibers (20 or 40 wt.% of cinnamon relative to the total polymer weight). Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) analyses of the nanofibers were performed. Antifungal activity was assessed through agar diffusion and colony-forming unit (CFU/mL) assays. Representative SEM morphological analysis was carried out to observe the presence/absence of C. albicans on the fibers. Alamar blue assay was used to determine cell toxicity. Analysis of variance and the Tukey's test were used to analyze the data (α = 0.05).

RESULTS

SEM imaging revealed nanofibers with adequate (i.e., bead-free) morphological characteristics and uniform microstructure. FTIR confirmed cinnamon incorporation. The cinnamon-laden nanofibers led to growth inhibition of C. albicans. Viable fungal counts support a significant reduction on CFU/mL also directly related to cinnamon concentration (40 wt.%: mean log 6.17 CFU/mL < 20 wt.%: mean log 7.12 CFU/mL), which agrees with the SEM images. Cinnamon-laden nanofibers at 40 wt.% led to increased cell death.

CONCLUSIONS

The deposition of 20 wt.% cinnamon-laden nanofibers onto PMMA surfaces led to a significant reduction of the adhesive and/or proliferative ability of C. albicans, while maintaining epithelial cells' viability.

CLINICAL RELEVANCE

The high recurrence rates of denture stomatitis are associated with patient non-adherence to treatments and contaminated prostheses use. Here, we provide the non-patients' cooperation sensible method, which possesses antifungal action, hence improving treatment effectiveness.

The Potential Role of Cinnamon in Human Health

Cinnamon is an unusual tropical plant belonging to the Lauraceae family. It has been used for hundreds of years as a flavor additive, but it has also been used in natural Eastern medicine. Cinnamon extracts are vital oils that contain biologically active compounds, such as cinnamon aldehyde, cinnamic alcohol, cinnamic acid, and cinnamate. It has antioxidant, anti-inflammatory, and antibacterial properties and is used to treat diseases such as diabetes and cardiovascular disease. In folk medicine, cinnamon species have been used as medicine for respiratory and digestive disorders. Their potential for prophylactic and therapeutic use in Parkinson’s and Alzheimer’s disease has also been discovered. This review summarizes the available isolation methods and analytical techniques used to identify biologically active compounds present in cinnamon bark and leaves and the influence of these compounds in the treatment of disorders.

Salivary microbial diversity at different stages of human immunodeficiency virus infection

Human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) disrupts the host microbial balance. During disease progression, the oral microbial environment is altered in untreated people living with HIV/AIDS (PLWHA); however, no studies have reported changes in salivary microbial diversity during different stages of HIV infection. Therefore, in this study, we aimed to assess the relationships between immune dysfunction and changes in saliva microbiota. To this end, we collected saliva samples from 11 HIV-negative individuals and 44 PLWHA during different stages based on the Centers for Disease Control and Prevention criteria (stage 0, early stage during the first 6 months after infection; stages 1, 2, and 3 associated with CD4⁺ T-lymphocyte counts of ≥500, 200-499, and ≤200 or opportunistic infection, respectively). We analyzed salivary microbial community diversity using polymerase chain reaction amplification and Illumina MiSeq sequencing. We found that HIV-positive individuals had significantly greater alpha-diversity in the microbial community composition compared with HIV-negative controls (P < 0.05) except for AIDS (stage 3); however, the predominant salivary microbiota in the five groups remained similar. Porphyromonas in the four positive groups was the only genus that was significantly less abundant in the HIV-positive groups than in the control group (P < 0.05). There were some consistencies between the general abundance of salivary microbiota and AIDS disease progression. Lots of bacterial abundances in the saliva increased dramatically during the acute HIV infection (stage 0), and some of the negligible and abnormally proliferating bacteria in the asymptomatic stage showed a downward trend. Additionally, in the AIDS stage, partial inhibition was observed. Notably, Porphyromonas was closely related to the immune activation of HIV, showing a decline in abundance once infected with HIV. Solobacterium, which induces inflammation, was negatively correlated with CD4 counts. Overall, our findings provided important insights into changes in salivary microbial diversity in PLWHA.

An Overview of the Potential Therapeutic Applications of Essential Oils

The emergence of antimicrobial resistance (AMR) has urged researchers to explore therapeutic alternatives, one of which includes the use of natural plant products such as essential oils (EO). In fact, EO obtained from clove, oregano, thymus, cinnamon bark, rosemary, eucalyptus, and lavender have been shown to present significant inhibitory effects on bacteria, fungi, and viruses; many studies have been done to measure EO efficacy against microorganisms. The strategy of combinatory effects via conventional and non-conventional methods revealed that the combined effects of EO-EO or EO-antibiotic exhibit enhanced efficacy. This paper aims to review the antimicrobial effects of EO, modes of EO action (membrane disruption, efflux inhibition, increase membrane permeability, and decrease in intracellular ATP), and their compounds' potential as effective agents against bacteria, fungi, and viruses. It is hoped that the integration of EO applications in this work can be used to consider EO for future clinical applications.

Effect of a Berry Polyphenolic Fraction on Biofilm Formation, Adherence Properties and Gene Expression of Streptococcus mutans and Its Biocompatibility with Oral Epithelial Cells

The ability of Streptococcus mutans to adhere to oral surfaces and form biofilm is a key step in the tooth decay process. The aim of this study was to investigate a berry (wild blueberry, cranberry, and strawberry) polyphenolic fraction, commercialized as Orophenol^®, for its antibacterial, anti-biofilm, and anti-adhesion properties on S. mutans. Moreover, the biocompatibility of the fraction with human oral epithelial cells was assessed. Phenolic acids, flavonoids (flavonols, anthocyanins, flavan-3-ols), and procyanidins made up 10.71%, 19.76%, and 5.29% of the berry polyphenolic fraction, respectively, as determined by chromatography and mass spectrometry. The berry polyphenolic preparation dose-dependently inhibited S. mutans biofilm formation while not reducing bacterial growth. At concentrations ranging from 250 to 1000 µg/mL, the fraction inhibited the adhesion of S. mutans to both saliva-coated hydroxyapatite and saliva-coated nickel-chrome alloy. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed that incubating S. mutans with the berry polyphenolic fraction was associated with a reduced expression of luxS gene, which regulates quorum sensing in S. mutans. The berry fraction did not show any significant cytotoxicity in an oral epithelial cell model. In conclusion, Orophenol^®, which is a mixture of polyphenols from wild blueberry, cranberry and strawberry, possesses interesting anti-caries properties while being compatible with oral epithelial cells.

Effect of essential oils on oral halitosis treatment: a review

Halitosis is a very common condition which may affect up to 30% of the population. In about 90% of the cases, halitosis originates in the mouth due to inadequate plaque control, periodontal disease, dry mouth, faulty restorations, and in particular due to excessive bacterial growth. Oral malodor is mainly caused by a microbial degradation of amino acids into volatile, bad-smelling gases (volatile sulfur compounds - VSCs). Management of oral malodor is directed primarily at managing and reducing the VSC-producing bacteria count as well as masking the odor. Essential oils have been used for this purpose in traditional medicine for centuries. In the present review, data on the antimicrobial activity of essential oils against relevant oral VSC-producing bacteria are compiled and compared. Additionally, other positive aspects of essential oils with regard to oral odor are considered.

Effects of Labrador Tea, Peppermint, and Winter Savory Essential Oils on Fusobacterium nucleatum

Bad breath or halitosis is an oral condition caused by volatile sulfur compounds (VSC) produced by bacteria found in the dental and tongue biofilms. Fusobacterium nucleatum is a Gram-negative anaerobic bacterium that has been strongly associated with halitosis. In this study, essential oils (EO) from three plants, Labrador tea (Rhododendron groenlandicum [Oeder] Kron & Judd), peppermint (Mentha x piperita L.), and winter savory (Satureja montana L.), were investigated for their effects on growth, biofilm formation and killing, and VSC production by F. nucleatum. Moreover, their biocompatibility with oral keratinocytes was investigated. Using a broth microdilution assay, winter savory EO and to a lesser extent Labrador tea and peppermint EO showed antibacterial activity against F. nucleatum. A treatment of pre-formed biofilms of F. nucleatum with EO also significantly decreased bacterial viability as determined by a luminescence assay monitoring adenosine triphosphate production. The EO were found to permeabilize the bacterial cell membrane, suggesting that it represents the target of the tested EO. The three EO under investigation were able to dose-dependently reduce VSC production by F. nucleatum. Lastly, no significant loss of cell viability was observed when oral keratinocytes were treated with the EO at concentrations effective against F. nucleatum. This study supports the potential of Labrador tea, peppermint, and winter savory EO as promising agents to control halitosis and promote oral health.

Effects of Cinnamon (Cinnamomum spp.) in Dentistry: A Review

Dental medicine is one of the fields of medicine where the most common pathologies are of bacterial and fungal origins. This review is mainly focused on the antimicrobial effects of cinnamon essential oil (EO), cinnamon extracts, and pure compounds against different oral pathogens and the oral biofilm and the possible effects on soft mouth tissue. Basic information is provided about cinnamon, as is a review of its antimicrobial properties against the most common microorganisms causing dental caries, endodontic and periodontal lesions, and candidiasis. Cinnamon EO, cinnamon extracts, and pure compounds show significant antimicrobial activities against oral pathogens and could be beneficial in caries and periodontal disease prevention, endodontics, and candidiasis treatment.

Antibiofilm activities of the cinnamon extract against Vibrio parahaemolyticus and Escherichia coli

Vibrio parahaemolyticus and Escherichia coli are two major foodborne pathogens. In this paper, the antibiofilm activities of the ethanol extract of cinnamon against these two bacteria were studied in detail. The antibacterial activity and the MIC of the extract were determined, and the inhibition and removing effects of the extract on the biofilms of V. parahaemolyticus and E. coli were investigated. The biofilms stained with fluorescein isothiocyanate (FITC) and concanavalin A (Con A) were also observed by confocal laser scanning microscope (CLSM). The results indicated that the extract exhibited high antibacterial activity, with the MIC against V. parahaemolyticus and E. coli was 6.25 mg/mL. The effects on V. parahaemolyticus biofilm were significant with the inhibition rate of 75.46% at MIC, and the eradication rate of 93.26% at 32MIC, respectively. As to E. coli, the inhibition rate was 48.18% at MIC, and the eradication rate was 46.16% at 8MIC. Meanwhile, the extract could notably reduce the metabolic activities and the secretion of EPS in biofilm, it inhibited 78.57% EPS formation in V. parahaemolyticus biofilm at MIC, and eliminated 61.28% EPS in mature biofilm at 4MIC. CLSM images showed that the EPS of the treated biofilm became thinner and biofilm structure was looser, when compared with the untreated control. This study elucidated that the cinnamon extract was effective to prevent biofilm formation and eradicate mature biofilms of V. parahaemolyticus and E. coli.

Hydrogen sulfide: An endogenous regulator of the immune system

Hydrogen sulfide (H₂S) is now recognized as an endogenous signaling gasotransmitter in mammals. It is produced by mammalian cells and tissues by various enzymes - predominantly cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST) - but part of the H₂S is produced by the intestinal microbiota (colonic H₂S-producing bacteria). Here we summarize the available information on the production and functional role of H₂S in the various cell types typically associated with innate immunity (neutrophils, macrophages, dendritic cells, natural killer cells, mast cells, basophils, eosinophils) and adaptive immunity (T and B lymphocytes) under normal conditions and as it relates to the development of various inflammatory and immune diseases. Special attention is paid to the physiological and the pathophysiological aspects of the oral cavity and the colon, where the immune cells and the parenchymal cells are exposed to a special "H₂S environment" due to bacterial H₂S production. H₂S has many cellular and molecular targets. Immune cells are "surrounded" by a "cloud" of H₂S, as a result of endogenous H₂S production and exogenous production from the surrounding parenchymal cells, which, in turn, importantly regulates their viability and function. Downregulation of endogenous H₂S producing enzymes in various diseases, or genetic defects in H₂S biosynthetic enzyme systems either lead to the development of spontaneous autoimmune disease or accelerate the onset and worsen the severity of various immune-mediated diseases (e.g. autoimmune rheumatoid arthritis or asthma). Low, regulated amounts of H₂S, when therapeutically delivered by small molecule donors, improve the function of various immune cells, and protect them against dysfunction induced by various noxious stimuli (e.g. reactive oxygen species or oxidized LDL). These effects of H₂S contribute to the maintenance of immune functions, can stimulate antimicrobial defenses and can exert anti-inflammatory therapeutic effects in various diseases.

Phytochemical and pharmacological review of Cinnamomum verum J. Presl-a versatile spice used in food and nutrition

Cinnamomum verum is the widely used spice for its medicinal and culinary uses since ages. It is native to Sri Lanka and southern India but also distributed in many Asian, Caribbean, Australian and African countries. It is widely used in food preparations and industrial products like candies, chewing gums, mouthwash and toothpaste. It is also used to treat asthma, bronchitis, diarrhea, headache, inflammation and cardiac disorders. Cinnamaldehyde, eugenol, caryophyllene, cinnamyl acetate and cinnamic acid are the major compounds found in its essential oil. These compounds exhibit a wide range of pharmacological activities including antioxidant, antimicrobial, anti-inflammatory, anticancer, antidiabetic, wound healing, anti-HIV, anti-anxiety and antidepressant, etc. This review highlights its comprehensive and up-to-date information on taxonomy, ethnomedicinal uses, phytochemical composition, pharmacological and toxicity activities. Structure-activity relationship, mechanism of action and some research gaps has also been provided. Owing to its immense medicinal importance, more well-designed in-vivo and clinical studies are required.

Determination of the effects of cinnamon bark fractions on Candida albicans and oral epithelial cells

Background

Candida albicans is an opportunistic pathogen that causes oral candidiasis and denture stomatitis. It has also been reported to infect oral mucositis lesions in patients who suffer from cancer affecting the head and neck and who receive chemotherapy and radiotherapy treatments. This study aimed to investigate the effects of two cinnamon bark fractions, i.e., an essential oil and an aqueous extract enriched in proanthocyanidins (Cinnulin PF®) on growth, biofilm formation, and adherence properties of C. albicans as well as on oral epithelial cells (barrier integrity, inflammatory response).

Methods

A microplate dilution assay was used to determine antifungal and anti-biofilm properties. A fluorescent assay was used to determine C. albicans adherence to oral epithelial cells. Cytotoxicity toward oral epithelial cells was assessed by determination of cell metabolic activity. Tight junction integrity of gingival keratinocytes was assessed by determination of transepithelial electrical resistance. IL-6 and IL-8 secretion by TNFα-stimulated oral epithelial cells was quantified by ELISA.

Results

While Cinnulin PF® did not reduce C. albicans growth, the cinnamon bark oil exhibited high antifungal activity with minimum inhibitory concentrations and minimum fungicidal concentrations in the range of 0.039 to 0.078%. The cinnamon oil was also active against a pre-formed C. albicans biofilm. Interestingly, Cinnulin PF® prevented biofilm formation by C. albicans and attenuated its adherence to oral epithelial cells. At their effective concentrations, the cinnamon oil and the Cinnulin PF® displayed no significant cytotoxicity against oral epithelial cells. In an in vitro model, both cinnamon fractions reinforced the integrity of the oral epithelial barrier. Lastly, Cinnulin PF® inhibited the secretion of interleukin-6 and interleukin-8 by oral epithelial cells stimulated with TNF-α.

Conclusion

By their ability to attenuate growth, biofilm formation and adherence property of C. albicans, to reinforce the epithelial barrier function, and to exert anti-inflammatory properties the two cinnamon fractions (essential oil, Cinnulin PF®) investigated in the present study may be promising agents for treating oral infections involving C. albicans.

Anti-Haemophilus Activity of Selected Essential Oils Detected by TLC-Direct Bioautography and Biofilm Inhibition

Essential oils (EOs) are becoming increasingly popular in medical applications because of their antimicrobial effect. Direct bioautography (DB) combined with thin layer chromatography (TLC) is a screening method for the detection of antimicrobial compounds in plant extracts, for example, in EOs. Due to their lipophilic character, the common microbiological assays (etc. disk diffusion) could not provide reliable results. The aim of this study was the evaluation of antibacterial and anti-biofilm properties of the EO of cinnamon bark, clove, peppermint, thyme, and their main components against Haemophilus influenzae and H. parainfluenzae. Oil in water (O/W) type Pickering nano-emulsions stabilized with silica nanoparticles from each oil were prepared to increase their water-solubility. Samples with Tween80 surfactant and absolute ethanol were also used. Results showed that H. influenzae was more sensitive to the EOs than H. parainfluenzae (except for cinnamon bark oil). In thin layer chromatography-direct bioautography (TLC-DB) the ethanolic solutions of thyme oil presented the best activity against H. influenzae, while cinnamon oil was the most active against H. parainfluenzae. Pickering nano-emulsion of cinnamon oil inhibited the biofilm formation of H. parainfluenzae (76.35%) more efficiently than samples with Tween80 surfactant or absolute ethanol. In conclusion, Pickering nano-emulsion of EOs could inhibit the biofilm production effectively.

A new technique for tongue brushing and halitosis reduction: the X technique

The tongue is one of the primary sources of halitosis. The manual or mechanical removal of biofilm is known to decrease oral malodor.