The tea catechin epigallocatechin gallate suppresses cariogenic virulence factors of Streptococcus mutans

Targeting glucosyltransferases to combat dental caries: Current perspectives and future prospects

The emergence of antimicrobial resistance within bacterial communities poses formidable challenges to existing therapeutic strategies aimed at mitigating biofilm-mediated infections. Recent advancements in this domain have spurred the development of targeted antimicrobial agents, designed to selectively eradicate the primary etiological agents while preserving the beneficial microbial diversity of the oral cavity. Targeting glucosyltransferases (GTFs), which play crucial roles in dental biofilm formation, offers a precise strategy to inhibit extracellular polysaccharide synthesis without compromising oral microbiota. This review article delves into the intricate mechanisms underlying dental caries, with a specific focus on the role of GTFs, enzymes produced by S. mutans. It further provides an overview of current research on GTF inhibitors, exploring their mechanisms of action, efficacy, and potential applications in clinical practice. Furthermore, it discusses the challenges and opportunities in the development of novel GTF inhibitors, emphasizing the need for innovative approaches to combat biofilm-mediated oral diseases effectively.

Green Tea Catechin Epigallocatechin Gallate Inhibits Vegetative Cell Outgrowth and Expression of Beta-Lactamase Genes in Penicillin-Resistant Bacillus anthracis Strain PCr

The green tea catechin epigallocatechin gallate (EGCg) has antimicrobial effects on many bacteria. In this study, we investigated the inhibitory effects of EGCg on Bacillus anthracis spores and vegetative cells. The B. anthracis spores were insensitive to EGCg, but the growth of vegetative cells derived from germinated spores was inhibited by EGCg. Moreover, EGCg decreased the minimum inhibitory concentration of penicillin and meropenem for penicillin-resistant B. anthracis. In the penicillin-resistant B. anthracis strain, the transcription levels of the beta-lactamase genes (bla1 and bla2) decreased significantly following the treatment with 50 µg/mL EGCg. These results suggest that the appropriate application of EGCg may effectively control the penicillin-resistant B. anthracis growth and beta-lactamase production.

Epigallocatechin gallate reduces the virulence of cariogenic Streptococcus mutans biofilm by affecting the synthesis of biofilm matrix components

INTRODUCTION

There have been reports on the effects of epigallocatechin gallate (EGCG) against Streptococcus mutans viability and acidogenesis. However, the effects of EGCG on the virulence of S. mutans biofilm development have yet to be fully investigated using validated cariogenic biofilm models.

OBJECTIVE

Thus, this study aimed to evaluate the effects of EGCG on S. mutans biofilm virulence using a validated cariogenic model and clinically relevant treatment regimens, twice a day for 1.5 min.

METHODS

Effects of EGCG on bacterial viability, polyssacharide synthesis and biofilm acidogenesis were evaluated. The morphology and 3D structure of the biofilms were evaluated by scanning electron (SEM) and confocal laser scanning microscopy, respectively.

RESULTS

No significant change in S. mutans viability or culture medium pH were observed when comparing EGCG-treated and NaCl-treated biofilms. EGCG significantly reduced the accumulation of soluble and insoluble polysaccharides, resulting in the formation of a biofilm with interspaced exopolysaccharide-microcolony complexes unevenly distributed on enamel. The SEM images of the biofilm treated with EGCG depict multilayers of cells arranged in short chains of microorganisms adhered to an unstructured matrix, which is not continuous and does not enmesh or protect the microorganisms entirely. Importantly, confocal images demonstrated that treatment with EGCG affected the 3D structure and organization of S. mutans biofilm, which presented a biofilm matrix more confined to the location of the microcolonies.

CONCLUSION

In conclusion, EGCG lowered the virulence of S. mutans matrix-rich biofilm by reducing the synthesis of biofilm matrix components, altering the biofilm matrix structure, organization, and distribution.

Effects of Green Tea Extract Epigallocatechin-3-Gallate on Oral Diseases: A Narrative Review

OBJECTIVES

Oral diseases are among the most prevalent diseases globally. Accumulating new evidence suggests considerable benefits of epigallocatechin-3-gallate (EGCG) for oral health. This review aims to explore the role and application of EGCG in main oral diseases.

METHODS

This narrative review thoroughly examines and summarizes the most recent literature available in scientific databases (PubMed, Web of Science, Scopus, and Google Scholar) reporting advances in the role and application of EGCG within the dental field. The major keywords used included "EGCG", "green tea extract", "oral health", "caries", "pulpitis", "periapical disease", "periodontal disease", "oral mucosa", "salivary gland", and "oral cancer".

CONCLUSIONS

EGCG prevents and manages various oral diseases through its antibacterial, anti-inflammatory, antioxidant, and antitumor properties. Compared to traditional treatments, EGCG generally exhibits lower tissue irritation and positive synergistic effects when combined with other therapies. Novel delivery systems or chemical modifications can significantly enhance EGCG's bioavailability, prolong its action, and reduce toxicity, which are current hotspots in developing new materials.

CLINICAL SIGNIFICANCE

this review provides an exhaustive overview of the biological activities of EGCG to major oral diseases, alongside an exploration of applications and limitations, which serves as a reference for preventing and managing oral ailments.

The potential of EGCG in modulating the oral-gut axis microbiota for treating inflammatory bowel disease

Inflammatory bowel disease (IBD) is a recurrent chronic intestinal disorder that includes ulcerative colitis (UC) and Crohn's disease (CD). Its pathogenesis involves intricate interactions between pathogenic microorganisms, native intestinal microorganisms, and the intestinal immune system via the oral-gut axis. The strong correlation observed between oral diseases and IBD indicates the potential involvement of oral pathogenic microorganisms in IBD development. Consequently, therapeutic strategies targeting the proliferation, translocation, intestinal colonization and exacerbated intestinal inflammation of oral microorganisms within the oral-gut axis may partially alleviate IBD. Tea consumption has been identified as a contributing factor in reducing IBD, with epigallocatechin gallate (EGCG) being the primary bioactive compound used for IBD treatment. However, the precise mechanism by which EGCG mediates microbial crosstalk within the oral-gut axis remains unclear. In this review, we provide a comprehensive overview of the diverse oral microorganisms implicated in the pathogenesis of IBD and elucidate their colonization pathways and mechanisms. Subsequently, we investigated the antibacterial properties of EGCG and its potential to attenuate microbial translocation and colonization in the gut, emphasizing its role in attenuating exacerbations of IBD. We also elucidated the toxic and side effects of EGCG. Finally, we discuss current strategies for enhancing EGCG bioavailability and propose novel multi-targeted nano-delivery systems for the more efficacious management of IBD. This review elucidates the role and feasibility of EGCG-mediated modulation of the oral-gut axis microbiota in the management of IBD, contributing to a better understanding of the mechanism of action of EGCG in the treatment of IBD and the development of prospective treatment strategies.

Exploring Plant-Based Compounds as Alternatives for Targeting Enterococcus faecalis in Endodontic Therapy: A Molecular Docking Approach

Endodontic infections pose significant challenges in dental practice due to their persistence and potential complications. Among the causative agents, Enterococcus faecalis stands out for its ability to form biofilms and develop resistance to conventional antibiotics, leading to treatment failures and recurrent infections. The urgent need for alternative treatments arises from the growing concern over antibiotic resistance and the limitations of current therapeutic options in combating E. faecalis-associated endodontic infections. Plant-based natural compounds offer a promising avenue for exploration, given their diverse bioactive properties and potential as sources of novel antimicrobial agents. In this study, molecular docking and dynamics simulations are employed to explore the interactions between SrtA, a key enzyme in E. faecalis, and plant-based natural compounds. Analysis of phytocompounds through molecular docking unveiled several candidates with binding energies surpassing that of the control drug, ampicillin, with pinocembrin emerging as the lead compound due to its strong interactions with key residues of SrtA. Comparative analysis with ampicillin underscored varying degrees of structural similarity among the study compounds. Molecular dynamics simulations provided deeper insights into the dynamic behavior and stability of protein-ligand complexes, with pinocembrin demonstrating minimal conformational changes and effective stabilization of the N-terminal region. Free energy landscape analysis supported pinocembrin's stabilizing effects, further corroborated by hydrogen bond analysis. Additionally, physicochemical properties analysis highlighted the drug-likeness of pinocembrin and glabridin. Overall, this study elucidates the potential anti-bacterial properties of selected phytocompounds against E. faecalis infections, with pinocembrin emerging as a promising lead compound for further drug development efforts, offering new avenues for combating bacterial infections and advancing therapeutic interventions in endodontic practice.

Antimicrobial Metabolites of Caucasian Medicinal Plants as Alternatives to Antibiotics

This review explores the potential of antimicrobial metabolites derived from Caucasian medicinal plants as alternatives to conventional antibiotics. With the rise of antibiotic resistance posing a global health threat, there is a pressing need to investigate alternative sources of antimicrobial agents. Caucasian medicinal plants have traditionally been used for their therapeutic properties, and recent research has highlighted their potential as sources of antimicrobial compounds. Representatives of 15 families of Caucasian medicinal plant extracts (24 species) have been explored for their efficacy against these pathogens. The effect of these plants on Gram-positive and Gram-negative bacteria and fungi is discussed in this paper. By harnessing the bioactive metabolites present in these plants, this study aims to contribute to the development of new antimicrobial treatments that can effectively combat bacterial infections while minimizing the risk of resistance emergence. Herein we discuss the following classes of bioactive compounds exhibiting antimicrobial activity: phenolic compounds, flavonoids, tannins, terpenes, saponins, alkaloids, and sulfur-containing compounds of Allium species. The review discusses the pharmacological properties of selected Caucasian medicinal plants, the extraction and characterization of these antimicrobial metabolites, the mechanisms of action of antibacterial and antifungal plant compounds, and their potential applications in clinical settings. Additionally, challenges and future directions in the research of antimicrobial metabolites from Caucasian medicinal plants are addressed.

Small RNA SmsR1 modulates acidogenicity and cariogenic virulence by affecting protein acetylation in Streptococcus mutans

Post-transcriptional regulation by small RNAs and post-translational modifications (PTM) such as lysine acetylation play fundamental roles in physiological circuits, offering rapid responses to environmental signals with low energy consumption. Yet, the interplay between these regulatory systems remains underexplored. Here, we unveil the cross-talk between sRNAs and lysine acetylation in Streptococcus mutans, a primary cariogenic pathogen known for its potent acidogenic virulence. Through systematic overexpression of sRNAs in S. mutans, we identified sRNA SmsR1 as a critical player in modulating acidogenicity, a key cariogenic virulence feature in S. mutans. Furthermore, combined with the analysis of predicted target mRNA and transcriptome results, potential target genes were identified and experimentally verified. A direct interaction between SmsR1 and 5'-UTR region of pdhC gene was determined by in vitro binding assays. Importantly, we found that overexpression of SmsR1 reduced the expression of pdhC mRNA and increased the intracellular concentration of acetyl-CoA, resulting in global changes in protein acetylation levels. This was verified by acetyl-proteomics in S. mutans, along with an increase in acetylation level and decreased activity of LDH. Our study unravels a novel regulatory paradigm where sRNA bridges post-transcriptional regulation with post-translational modification, underscoring bacterial adeptness in fine-tuning responses to environmental stress.

Epigallocatechin gallate-immobilized antimicrobial resin with rechargeable fluorinated synergistic composite for enhanced caries control

OBJECTIVES

Given the global prevalence of dental caries, impacting 2.5 billion individuals, the development of sophisticated prevention filling materials is crucial. Streptococcus mutans, the principal caries-causing strain, produces acids that demineralize teeth and initiate dental caries. To address this issue, we aimed to develop a synergistic resin-based composite for enhancing caries control.

METHODS

The synergistic resin composite incorporates fluorinated kaolinite and silanized Al2O3 nanoparticle fillers into an epigallocatechin gallate (EGCG) immobilized urethane-modified epoxy acrylate (U-EA) resin matrix, referred to the as-prepared resin composite. The EGCG-modified TPGDA/U-EA network was synthesized by preparing methacrylate-functionalized isocyanate (HI), reacting it with EGCG to form HI-EGCG, and then incorporating HI-EGCG into the TPGDA/U-EA matrix. The lamellar space within the kaolinite layer was expanded through the intercalation of acrylamide into kaolinite, enhancing its capability to adsorb and release fluoride ions (F-). The layered structure of acrylamide/ kaolinite in the U-EA resin composite acts as a F- reservoir.

RESULTS

The physico-mechanical properties of the as-prepared resin composites are comparable to those of commercial products, exhibiting lower polymerization shrinkage, substantial F- release and recharge and favorable diametral tensile strength. The immobilized EGCG in the composite exhibits potent antimicrobial properties, effectively reducing the biofilm biomass. Furthermore, the synergistic effect of EGCG and fluorinated kaolinite efficiently counteracts acid-induced hydroxyapatite dissolution, thereby suppressing demineralization and promoting enamel remineralization.

SIGNIFICANCE

Our innovative EGCG and fluoride synergistic composite provides enhanced antimicrobial properties, durable anti-demineralization, and tooth remineralization effects, positioning it as a promising solution for effective caries control and long-term dental maintenance.

How probiotics, prebiotics, synbiotics, and postbiotics prevent dental caries: an oral microbiota perspective

Dental caries, a highly prevalent oral disease, impacts a significant portion of the global population. Conventional approaches that indiscriminately eradicate microbes disrupt the natural equilibrium of the oral microbiota. In contrast, biointervention strategies aim to restore this balance by introducing beneficial microorganisms or inhibiting cariogenic ones. Over the past three decades, microbial preparations have garnered considerable attention in dental research for the prevention and treatment of dental caries. However, unlike related pathologies in the gastrointestinal, vaginal, and respiratory tracts, dental caries occurs on hard tissues such as tooth enamel and is closely associated with localized acid overproduction facilitated by cariogenic biofilms. Therefore, it is insufficient to rely solely on previous mechanisms to delineate the role of microbial preparations in the oral cavity. A more comprehensive perspective should involve considering the concepts of cariogenic biofilms. This review elucidates the latest research progress, mechanisms of action, challenges, and future research directions regarding probiotics, prebiotics, synbiotics, and postbiotics for the prevention and treatment of dental caries, taking into account the unique pathogenic mechanisms of dental caries. With an enhanced understanding of oral microbiota, personalized microbial therapy will emerge as a critical future research trend.

Anticaries properties of natural berries: systematic literature review

CONTEXT

Anticariogenic properties have been ascribed to polyphenolic compounds present in high concentrations in numerous fruits. Berries, in particular, have been reported as potentially having an inhibitory effect on the dental biofilm and subsequently on caries, but the evidence is unclear.

OBJECTIVE

The objective of this review was to explore the literature and summarize the evidence for berries having an inhibitory effect on the dental biofilm and an anticariogenic effect.

DATA SOURCES

Following Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, the PubMed, Web of Science, and SCOPUS databases were scanned using predefined and accessible terms, with a search strategy based on a structured PICO question.

DATA EXTRACTION

After article selection, 23 studies met the inclusion criteria, most of them being in vitro studies. A risk assessment was performed, and data were extracted and presented in a table for qualitative analysis.

DATA ANALYSIS

Meta-analyses were conducted using standardized mean differences (SMDs) with a 95% confidence interval (CI) by Review manager 5.4.

RESULTS

Only 3 types of berries were found to have a reported anticaries effect: grape seed extract (GSE), cranberry, and sour cherry. Nine studies that fulfilled the eligibility criteria were subjected to quantitative analysis. Meta-analyses showed GSE was associated with enhanced remineralization of dental enamel (SMD = .96 95% CI [.45, 1.46], P < .0002) and of dentin (SMD = .65 95% CI [.13, 1.17], P = .01). Cranberry extracts positively influenced the cariogenic dental biofilm by decreasing the biofilm biomass (SMD = -2.23 95% CI [-4.40, -.05], P = .04), and biovolume (SMD = -2.86 95% CI [-4.34, -1.37], P = .0002), and increasing the biofilm pH (SMD = 7.9 95% CI [3.49, 12.31], P < .0004).

CONCLUSION

Within the limitations of this systematic review and metaanalysis, GSE and cranberries or their active compounds could represent an alternative for caries management. Further clinical trials are needed to verify this effect in a clinical setting.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42020223579.

Flavonoids effects against bacteria associated to periodontal disease and dental caries: a scoping review

This scoping review focused on exploring the efficacy of flavonoids against bacteria associated with dental caries and periodontal diseases. Inclusion criteria comprise studies investigating the antibacterial effects of flavonoids against bacteria linked to caries or periodontal diseases, both pure or diluted in vehicle forms. The search, conducted in August 2023, in databases including PubMed/MEDLINE, Scopus, Web of Science, Embase, LILACS, and Gray Literature. Out of the initial 1125 studies, 79 met the inclusion criteria, majority in vitro studies. Prominent flavonoids tested included epigallocatechin-gallate, apigenin, quercetin, and myricetin. Predominant findings consistently pointed to bacteriostatic, bactericidal, and antibiofilm activities. The study primarily investigated bacteria associated with dental caries, followed by periodontopathogens. A higher number of publications presented positive antibacterial results against Streptococcus mutans in comparison to Porphyromonas gingivalis. These encouraging findings underline the potential applicability of commercially available flavonoids in materials or therapies, underscoring the need for further exploration in this field.

Chitosan nanoparticles loaded with epigallocatechin-3-gallate: synthesis, characterisation, and effects against Streptococcus mutans biofilmEpigallocatechin-loaded chitosan nanoparticles: effects against Streptococcus mutans biofilm

This study evaluated the effects of chitosan nanoparticles loaded with epigallocatechin-3-gallate (EGCG) against Streptococcus mutans biofilm. EGCG-loaded chitosan (Nchi + EGCG) nanoparticles and Chitosan (Nchi) nanoparticles were prepared by ion gelation process and characterised regarding particle size, polydispersion index, zeta potential, and accelerated stability. S mutans biofilms were treated twice daily with NaCl 0.9% (negative control), Nchi, Nchi + EGCG, and chlorhexidine (CHX) 0.12% (positive control). After 67 h, the biofilms were evaluated for acidogenesis, bacterial viability and dry weight. Biofilm morphology and structure were analysed by scanning electron microscopy. The nanoformulations presented medium to short-term stability, size of 500 nm, and polydispersion index around 0.400. Treatments affected cell morphology and biofilm structure. However, no effects on microbial viability, biofilm dry weight, and acidogenesis were observed. Thus, the nanoformulations disassembled the biofilm matrix without affecting microbial viability, which makes them promising candidates for the development of dental caries preventive and therapeutic agents.

Antibacterial efficacy of epigallocatechin-3-gallate cross-linked small intestinal submucosa guided bone regeneration membrane

The leading cause of guided bone regeneration (GBR) failure is infection. Herein, we developed a new GBR membrane with good mechanical and osteogenic properties by crosslinking the small intestinal submucosa (SIS) with epigallocatechin-3-gallate (EGCG). Meanwhile, EGCG is also a natural antibacterial agent. This study aimed to investigate the antibacterial efficacy of EGCG-crosslinked SIS (E-SIS) against Staphylococcus aureus and Escherichia coli through EGCG release, bacterial count, live/dead staining, scanning electron microscopy, growth curve, and biofilm formation tests. The results showed that E-SIS effectively inhibited bacteria's growth and adhesion, and its antibacterial activity against Staphylococcus aureus was stronger than that against Escherichia coli. 0.5% E-SIS had the most potent antibacterial activity. The antibacterial mechanism of E-SIS might be related to the release of EGCG and the surface properties of E-SIS. In conclusion, 0.5% E-SIS is a promising GBR membrane with good osteogenic and antibacterial properties.

Antimicrobial peptide temporin derivatives inhibit biofilm formation and virulence factor expression of Streptococcus mutans

Introduction

Temporin-GHa obtained from the frog Hylarana guentheri showed bactericidal efficacy against Streptococcus mutans. To enhance its antibacterial activity, the derived peptides GHaR and GHa11R were designed, and their antibacterial performance, antibiofilm efficacy and potential in the inhibition of dental caries were evaluated.

Methods

Bacterial survival assay, fluorescent staining assay and transmission electron microscopy observation were applied to explore how the peptides inhibited and killed S. mutans. The antibiofilm efficacy was assayed by examining exopolysaccharide (EPS) and lactic acid production, bacterial adhesion and cell surface hydrophobicity. The gene expression level of virulence factors of S. mutans was detected by qRT-PCR. Finally, the impact of the peptides on the caries induced ability of S. mutans was measured using a rat caries model.

Results

It has been shown that the peptides inhibited biofilm rapid accumulation by weakening the initial adhesion of S. mutans and reducing the production of EPS. Meanwhile, they also decreased bacterial acidogenicity and aciduricity, and ultimately prevented caries development in vivo.

Conclusion

GHaR and GHa11R might be promising candidates for controlling S. mutans infections.

Green Tea-Derived Catechins Suppress the Acid Productions of Streptococcus mutans and Enhance the Efficiency of Fluoride

Green tea-derived catechins, which can be divided into galloylated (epicatechin gallate: ECG, epigallocatechin gallate: EGCG) and non-galloylated (catechin: C, epicatechin: EC, epigallocatechin: EGC) catechins, are considered to be the main contributors to the caries control potential of green tea. In this study, we intended to compare the antimicrobial effects of these representative green tea-derived catechins and their combined effects with fluoride on the acid production and aggregation of Streptococcus mutans. The effects of different catechins on the growth, aggregation and acid production of S. mutans, and the combined effect of catechins and potassium fluoride (2 mm at pH 7.0, 0.3 mm at pH 5.5) on S. mutans acid production were measured by anaerobic culture, turbidity changes due to aggregation, and pH-stat methods. Molecular docking simulations were also performed to investigate the interactions between catechins and membrane-embedded enzyme II complex (EIIC), a component of the phosphoenolpyruvate-dependent phosphotransferase system (sugar uptake-related enzyme). ECG or EGCG at 1 mg/mL significantly inhibited the growth of S. mutans, induced bacterial aggregation, and decreased glucose-induced acid production (p < 0.05). All catechins were able to bind to EIIC in silico, in the following order of affinity: EGCG, ECG, EGC, EC, and C. Furthermore, they enhanced the inhibitory effects of fluoride at pH 5.5 and significantly inhibited S. mutans acid production by 47.5-86.6% (p < 0.05). These results suggest that both galloylated and non-galloylated catechins exhibit antimicrobial activity, although the former type demonstrates stronger activity, and that the caries control effects of green tea may be due to the combined effects of multiple components, such as catechins and fluoride. The detailed mechanisms underlying these phenomena and the in vivo effect need to be explored further.

Engineered Biomaterials Trigger Remineralization and Antimicrobial Effects for Dental Caries Restoration

Dental caries is the most prevalent chronic disease globally, significantly impacting individuals' quality of life. A key reason behind the failure of implanted restorations is their biological inactivity, meaning they are unable to form crosslinks with the surrounding tooth structures, thus making patients susceptible to implant loss and recurrent tooth decay. For the treatment of caries, antibacterial medicine and remineralization are effective means of treating the recurrence of caries. Owing to the rapid progression in the biomaterials field, several biomaterials have been reported to display antimicrobial properties and aid in dentin remineralization. Bioactive materials hold considerable potential in diminishing biofilm accumulation, inhibiting the process of demineralization, enabling dentin remineralization, and combating bacteria related to caries. Bioactive materials, such as fluoride, amorphous calcium phosphate, bioactive glass, collagen, and resin-based materials, have demonstrated their effectiveness in promoting dentin remineralization and exerting antibacterial effects on dental caries. However, the concentration of fluoride needs to be strictly controlled. Although amorphous calcium phosphate can provide the necessary calcium and phosphorus ions for remineralization, it falls short in delivering the mechanical strength required for oral mastication. Resin-based materials also offer different advantages due to the complexity of their design. In this review, we delve into the application of advanced bioactive materials for enhancing dentin remineralization and antibacterial properties. We eagerly anticipate future developments in bioactive materials for the treatment of dental caries.

Effects of Sulforaphene on the Cariogenic Properties of Streptococcus Mutans In Vitro and Dental Caries Development In Vivo

Sulforaphene (SFE) is a common nutritional supplement with antibacterial, anti-cancer, and anti-inflammatory effects. However, the effects of SFE on the cariogenicity of Streptococcus mutans and dental caries have not been reported. The objectives of this study were to investigate the caries-controlling potential of SFE. The effects of SFE on S. mutans were investigated using the broth microdilution method, crystal violet staining, SEM observation, acid tolerance assays, lactic acid quantification, and polysaccharide measurements. A rat caries model was established to evaluate the caries-controlling effects and biocompatibility of SFE in vivo. SFE inhibited S. mutans growth and biofilm formation. Furthermore, SFE restrained the cariogenic properties of S. mutans, including its acid production, acid tolerance, and extracellular polysaccharide production, without affecting the bacterial viability at sub-inhibitory levels. In the rat caries model, SFE significantly arrested the onset and development of dental caries. Moreover, no visible hemolytic phenomenon or cytotoxicity was detected in the SFE groups. After four weeks of SFE treatment, all rats remained in apparent good health with no significant differences in weight gain; their hemogram and biochemical parameters were normal; no pathological changes were observed in the oral mucosa, liver, or kidneys. In conclusion, SFE was safe and inhibited the development of caries effectively.

Tea Polyphenols Protects Tracheal Epithelial Tight Junctions in Lung during Actinobacillus pleuropneumoniae Infection via Suppressing TLR-4/MAPK/PKC-MLCK Signaling

Actinobacillus pleuropneumoniae (APP) is the causative pathogen of porcine pleuropneumonia, a highly contagious respiratory disease in the pig industry. The increasingly severe antimicrobial resistance in APP urgently requires novel antibacterial alternatives for the treatment of APP infection. In this study, we investigated the effect of tea polyphenols (TP) against APP. MIC and MBC of TP showed significant inhibitory effects on bacteria growth and caused cellular damage to APP. Furthermore, TP decreased adherent activity of APP to the newborn pig tracheal epithelial cells (NPTr) and the destruction of the tight adherence junction proteins β-catenin and occludin. Moreover, TP improved the survival rate of APP infected mice but also attenuated the release of the inflammation-related cytokines IL-6, IL-8, and TNF-α. TP inhibited activation of the TLR/MAPK/PKC-MLCK signaling for down-regulated TLR-2, TLR4, p-JNK, p-p38, p-PKC-α, and MLCK in cells triggered by APP. Collectively, our data suggest that TP represents a promising therapeutic agent in the treatment of APP infection.

Analysis of the Polyphenolic Composition of Vaccinium L. Extracts and Their Protective Effect on Red Blood Cell Membranes

The blueberry fruit of the genus Vaccinium, including high blueberry, low blueberry, and wild bilberry, is consumed for its flavor and medicinal properties. The purpose of the experiments was to investigate the protective effect and mechanism of the interaction of blueberry fruit polyphenol extracts with the erythrocytes and their membranes. The content of polyphenolic compounds in the extracts was determined using the chromatographic UPLC-ESI-MS method. The effects of the extracts on red blood cell shape changes, hemolysis and osmotic resistance were examined. Changes in the order of packing and fluidity of the erythrocyte membrane and the lipid membrane model caused by the extracts were identified using fluorimetric methods. Erythrocyte membrane oxidation was induced by two agents: AAPH compound and UVC radiation. The results show that the tested extracts are a rich source of low molecular weight polyphenols that bind to the polar groups of the erythrocyte membrane, changing the properties of its hydrophilic area. However, they practically do not penetrate the hydrophobic part of the membrane and do not damage its structure. Research results suggest that the components of the extracts can defend the organism against oxidative stress if they are delivered to the organism in the form of dietary supplements.

3,3'-Diindolylmethane (DIM): A Potential Therapeutic Agent against Cariogenic Streptococcus mutans Biofilm

Indole, a metabolite of the amino acid tryptophan, has been proven to act as a signal molecule in bacteria, acting in different aspects of biofilm formation. The oral biofilm is a type of biofilm that has consequences for human health. It is a complex, three-dimensional structure that develops on the surface of teeth via the attachment of primary microbial colonizers. Many oral infections are caused by an imbalance occurring in the microorganisms naturally found in oral biofilms and are considered major public health concerns. In this study, we test the effect of a natural bis-indole, 3,3'-Diindolylmethane (DIM), in mitigating the pathogenicity of the oral biofilm inhabiting bacterium Streptococcus mutans, a bacterium that is considered to be a principal etiological agent in dental caries. Our study found that DIM was able to attenuate S. mutans biofilm formation by 92%. Additionally, treatment with DIM lowered extracellular polymeric substance (EPS) production and decreased its durability significantly under acidic conditions. Therefore, the anti-biofilm and anti-virulence properties of DIM against S. mutans bacteria in an "oral setting" provides evidence for its usefulness in reducing biofilm formation and potentially for caries attenuation.

Application of QSAR Approach to Assess the Effects of Organic Pollutants on Bacterial Virulence Factors

The release of a wide variety of persistent chemical contaminants into wastewater has become a growing concern due to their potential health and environmental risks. While the toxic effects of these pollutants on aquatic organisms have been extensively studied, their impact on microbial pathogens and their virulence mechanisms remains largely unexplored. This research paper focuses on the identification and prioritization of chemical pollutants that increase bacterial pathogenicity, which is a public health concern. In order to predict how chemical compounds, such as pesticides and pharmaceuticals, would affect the virulence mechanisms of three bacterial strains (Escherichia coli K12, Pseudomonas aeruginosa H103, and Salmonella enterica serovar. Typhimurium), this study has developed quantitative structure-activity relationship (QSAR) models. The use of analysis of variance (ANOVA) functions assists in developing QSAR models based on the chemical structure of the compounds, to predict their effect on the growth and swarming behavior of the bacterial strains. The results showed an uncertainty in the created model, and that increases in virulence factors, including growth and motility of bacteria, after exposure to the studied compounds are possible to be predicted. These results could be more accurate if the interactions between groups of functions are included. For that, to make an accurate and universal model, it is essential to incorporate a larger number of compounds of similar and different structures.

Epigallocatechin-3-gallate/mineralization precursors co-delivery hollow mesoporous nanosystem for synergistic manipulation of dentin exposure

As a global public health focus, oral health plays a vital role in facilitating overall health. Defected teeth characterized by exposure of dentin generally increase the risk of aggravating oral diseases. The exposed dentinal tubules provide channels for irritants and bacterial invasion, leading to dentin hypersensitivity and even pulp inflammation. Cariogenic bacterial adhesion and biofilm formation on dentin are responsible for tooth demineralization and caries. It remains a clinical challenge to achieve the integration of tubule occlusion, collagen mineralization, and antibiofilm functions for managing exposed dentin. To address this issue, an epigallocatechin-3-gallate (EGCG) and poly(allylamine)-stabilized amorphous calcium phosphate (PAH-ACP) co-delivery hollow mesoporous silica (HMS) nanosystem (E/PA@HMS) was herein developed. The application of E/PA@HMS effectively occluded the dentinal tubules with acid- and abrasion-resistant stability and inhibited the biofilm formation of Streptococcus mutans. Intrafibrillar mineralization of collagen fibrils and remineralization of demineralized dentin were induced by E/PA@HMS. The odontogenic differentiation and mineralization of dental pulp cells with high biocompatibility were also promoted. Animal experiments showed that E/PA@HMS durably sealed the tubules and inhibited biofilm growth up to 14 days. Thus, the development of the E/PA@HMS nanosystem provides promising benefits for protecting exposed dentin through the coordinated manipulation of dentin caries and hypersensitivity.

Anticariogenic Activity of Black Tea: An In Vivo Study

BACKGROUND

The prevention of dental caries has always remained a challenge. Caries prevention through dietary intervention holds promise. Studies have revealed that several constituents present in tea have anticariogenic properties. Tea is a widely consumed beverage and hence could be utilized as a suitable caries preventive agent. The purpose of this study was to determine the effect of black tea on caries progression in experimental animals.

MATERIALS AND METHODS

This study was carried out in 17-day-old albino rat pups. The animals were divided into three groups, with eight animals in each group. They were fed on a cariogenic diet (MIT 200) and inoculated with Streptococcus mutans. Group I was given MIT 200 with water, Group II was placed on MIT 200 with black tea, and Group III was placed on MIT 200 with fluoridated water for a period of 45 days. After 45 days, the animals were killed under ether anesthesia, and their teeth were examined for caries.

RESULTS

The carious lesions were scored for the first two molars in each quadrant. In each group, a total of 64 teeth were examined. The caries score between the upper and lower jaws was compared using ANOVA.

CONCLUSION

From this study, it may be inferred that drinking black tea reduced the development of dental caries in young rats fed on a cariogenic diet. The tea used for this study was prepared using fluoride-free water, so we can assume that besides fluoride, certain components are present in tea leaves that possess anticariogenic properties.

Efficacy of ozonated water as a PS in photodynamic therapy: A tool for dental caries management? An in vitro study

Background

The most prevalent noncommunicable disease in the world is dental caries; and when it is not adequately treated, it is usually associated with tooth loss or severe dental lesions. In fact, expensive care or tooth extraction may be necessary due to the negative effects dental caries have on general health. This is due to its frequent pain and secondary bacterial infections. The aim of this study was to investigate the activity of ozonated water as such and in combination with appropriate light radiation so as to perform a photodynamic treatment (PDT) against the cariogenic bacterium Streptococcus mutans.

Design and methods

This work has been performed in vitro by using an S. mutans strain mainly structured in a biofilm status, reproducing the natural condition of the tooth infection. The ozone was tested at three different concentrations by using a commercial device able to generate different O3 formulations in water. The PDT treatment requires an appropriate light wavelength, evaluated in this work through the UV-Vis adsorption spectrum of the ozonated water.

Results

The obtained results suggested an effective and synergic property of O3 and light at 460-470 nm against this microorganism. The most antibiofilm activity was observed using a concentration of ozone of 0.06 mg/L alone as well as with PDT treatment.

Conclusions

The results are encouraging for additional research and in vitro/in vivo fresh experimental investigations to perform an exhaustive antimicrobial treatment protocol against the S. mutans tooth infection.

Novel Lactotransferrin-Derived Antimicrobial Peptide LF-1 Inhibits the Cariogenic Virulence Factors of Streptococcus mutans

We previously developed a novel lactotransferrin-derived antimicrobial peptide, LF-1, with selective antibacterial activity against the characteristic cariogenic bacterium Streptococcus mutans. This study further investigated the effects of LF-1 on the cariogenic virulence factors of S. mutans and evaluated the changes in virulence-associated enzymes and genes; the viability, acidogenicity, and aciduricity of planktonic S. mutans; and initial colonisation and biofilm formation after treatment with LF-1. The method of qRT-PCR was used to evaluate S. mutans virulence-associated gene expression. LF-1 interfered with the cell viability of S. mutans within 6 h. LF-1 inhibited the acidogenicity and aciduricity of S. mutans, with reduced lactic acid production and survival in a lethal acidic environment, and inactivated lactate dehydrogenase and F1F0-ATPase activity. LF-1 decreased surface-adherent S. mutans within 60 min and inhibited S. mutans biofilm formation, where scanning electron microscopy and confocal laser scanning microscopy showed reduced extracellular matrix and bacteria. LF-1 downregulates S. mutans virulence-associated gene expression. LF-1 inhibited the growth and cariogenic virulence factors of S. mutans in vitro with a reduction in key enzymatic activity and downregulation of virulence-associated gene expression. LF-1 has promising application prospects in the fight against S. mutans and dental caries.

Antibacterial Activity of Epigallocatechin Gallate (EGCG) against Shigella flexneri

Shigella flexneri (S. flexneri), a major intestinal pathogen, is a global public health concern. The biofilms formed by S. flexneri threaten environmental safety, since they could promote the danger of environmental contamination and strengthen the disease-causing properties of bacteria. Epigallocatechin gallate (EGCG) is an important catechin in tea, which has a high antibacterial activity. However, its antibacterial mechanism is still unclear. This research aims to quantify the antibacterial function and investigate the possible mechanism of EGCG inhibition of S. flexneri. The minimum inhibitory concentration (MIC) of EGCG against planktonic S. flexneri in the investigation was measured to be 400 μg/mL. Besides, SDS-PAGE and field emission scanning electron microscopy showed that EGCG interfered with protein synthesis and changed bacteria morphology. Through controlling the expression of the mdoH gene, EGCG was found to be able to prevent an S. flexneri biofilm extracellular polysaccharide from forming, according to experiments utilizing the real-time PCR test. Additional research revealed that EGCG might stimulate the response of S. flexneri to oxidative stress and prevent bacterial growth. These findings suggest that EGCG, a natural compound, may play a substantial role in S. flexneri growth inhibition.

mltG gene deletion mitigated virulence potential of Streptococcus mutans: An in-vitro, ex-situ and in-vivo study

Bacterial cells are surrounded by a peptidoglycan (PG) cell wall, which is essential for cell integrity and intrinsic biogenesis pathways; hence, the cell wall is a potential target for several antibiotics. Among several lytic transglycosylases (LTs), the mltG gene plays a crucial role in the synthesis of peripheral PG. It localises the re-modelled PGs for septum formation and cleavage across the bacterial cell wall during daughter cells separation. However, the role of mltG gene in bacterial virulence, particularly in Gram-positive bacteria during dentine biofilm and caries development, has remained unexplored. Hence, we exploited Gram-positive Streptococcus mutans cells for the very first time to construct a mltG knock-out bacterial strain, e.g., ΔmltG S. mutans. Systematic comparative investigations revealed that doubling time (Td), survival, enzymatic efficiencies, pH tolerance, bio-synthesise of lipid, proteins and DNA, biofilm formation and dentine lesions were significantly (p < 0.001) compromised in case of ΔmltG S. mutans than wild type strain. The qRT-PCR based gene expression profiling revealed that transcriptional expression of critically important genes involved in biofilm, metabolism, and stress response were dysregulated in the mutant. Besides, an incredible reduction in dentine caries development was found in the molar teeth of Wistar rats and also in human extracted teeth. Concisely, these trends obtained evidently advocated the fact that the deletion of mltG gene can be a potential target to impair the S. mutans virulence through severe growth retardation, thereby reducing the virulence potential of S. mutans.

A review on the immunomodulatory properties of functional nutraceuticals as dietary interventions for children to combat COVID-19 related infections

COVID-19 is a significant threat to humanity in the present day due to the rapid increase in the number of infections worldwide. While most children may be spared of the direct mortality effects of the disease, those with weak immune systems are prone to adverse effects. Child mortality increases due to the stress caused to the health care system that disrupts essential health care needs such as immunisation and antenatal care. The use of functional foods (FF) aids in disease-prevention as they are known to have protective effects against COVID-19 by boosting children’s cellular and humoral immunity. Plant components such as glycyrrhizin, epigallocatechin gallate, allicin, and fucoidan exhibit antiviral properties against various viruses, including SARS-CoV 2. Microbial foods that are made of probiotics, can enhance immunity against various respiratory viruses. Food enriched with additives such as lactoferrin, piperine, and zinc can boost immunity against COVID-19. With proper definitive drug therapy not available for treating COVID-19 and most of the disease management tools rely on symptoms and non-specific supportive care, developing a functional paediatric formulation will prevent further deterioration in infant health. It is wise to investigate the toxicological aspects of Functional Foods components especially when formulating for children. The safe limits of ingredients should be strictly followed during FFs formulation. Stronger regulations with advanced analytical techniques can help to formulate functional foods into the mainstream in child nutraceuticals. The purpose of this review is to compile collective information on the functional nutraceuticals specifically for infants and children up to the age of 10 years that could confer immunity against COVID-19 and other related viruses.

Effects of green tea extract epigallocatechin-3-gallate (EGCG) on oral disease-associated microbes: a review

For thousands of years, caries, periodontitis and mucosal diseases, which are closely related to oral microorganisms, have always affected human health and quality of life. These complex microbiota present in different parts of the mouth can cause chronic infections in the oral cavity under certain conditions, some of which can also lead to acute and systemic diseases. With the mutation of related microorganisms and the continuous emergence of drug-resistant strains, in order to prevent and treat related diseases, in addition to the innovation of diagnosis and treatment technology, the development of new antimicrobial drugs is also important. Catechins are polyphenolic compounds in green tea, some of which are reported to provide health benefits for a variety of diseases. Studies have shown that epigallocatechin-3-gallate (EGCG) is the most abundant and effective active ingredient in green tea catechins, which acts against a variety of gram-positive and negative bacteria, as well as some fungi and viruses. This review aims to summarize the research progress on the activity of EGCG against common oral disease-associated organisms and discuss the mechanisms of these actions, hoping to provide new medication strategies for the prevention and treatment of oral infectious diseases, the future research of EGCG and its translation into clinical practice are also discussed.

Comparison of collagen features of distinct types of caries-affected dentin

OBJECTIVES

To compare the biodegradability, mechanical behavior, and physicochemical features of the collagen-rich extracellular matrix (ECM) of artificial caries-affected dentin (ACAD), natural caries-affected dentin (NCAD) and sound dentin (SD).

METHODS

Dentin specimens from human molars were prepared and assigned into groups according to the type of dentin: ACAD, NCAD, or SD. ACAD was produced by incubation of demineralized SD with Streptococcus mutans in a chemically defined medium (CDM) with 1% sucrose for 7 days at 37 °C under anaerobic conditions. Specimens were assessed to determine collagen birefringence, biodegradability, mechanical behavior, and chemical composition. Data were individually processed and analyzed by ANOVA and post-hoc tests (α = 0.05).

RESULTS

CDM-based biofilm challenge reduced loss, storage, and complex moduli in ACAD (p < 0.001), while the damping capacity remained unaffected (p = 0.066). Higher red and lower green birefringence were found in ACAD and NCAD when compared with SD (p < 0.001). Differently to ACAD, SD and NCAD presented higher biodegradability to exogenous proteases (p = 0.02). Chemical analysis of the integrated areas of characteristic bands that assess mineral quality (carbonate/phosphate and crystallinity index), mineral to matrix (phosphate/amide I) and post-translational modifications (amide III/CH₂, pentosidine/CH₂, and pentosidine/amide III) (p<0.05) showed that NCAD was significantly different from SD while ACAD exhibited intermediate values.

CONCLUSIONS

CDM-based biofilm challenge produced a dentin ECM with decreased mechanical properties and increased collagen maturity. The compositional and structural conformation of the ACAD suggested that CDM-based biofilm challenge showed potential to produce artificial lesions by revealing a transitional condition towards mimicking critical features of NCAD.

CLINICAL SIGNIFICANCE

This study highlights the importance of developing a tissue that mimics the features of natural caries-affected dentin ECM for in vitro studies. Our findings suggested the potential of a modified biofilm challenge protocol to produce and simulate a relevant substrate, such as caries-affected dentin.

Immune-biochemical response and immune gene expression profiling of Labeo rohita fingerlings fed with ethanolic tea leaf extracts and its survivability against Aeromonas hydrophila infection

The present study was conducted to evaluate the immunostimulatory effect of tea leaf extract (Camellia sinensis) on Labeo rohita and its resistance against Aeromonas hydrophila infection. The ethanolic extract of green tea (GTEE) was found to be the most potent as compared to other solvent extract which was used for further study. It was used to evaluate immune-biochemical response of L. rohita fingerlings, fed with tea leaf extract (control- 0.0%, 0.2% (T1), 0.4% (T2), 0.8% (T3) and 1% (T4) of GTEE kg^-1 feed). Different biochemical parameters like glucose, ALP, GPT, GOT, and immunological parameters like lysozyme activity, NBT, anti-protease activity, myeloperoxidase activity, plasma protein, and immune relevant genes (IL-10, C3, Lysozyme G type and iNOS) expressions were carried out. The immunological parameters such as lysozyme activity, NBT and myeloperoxidase activity showed significantly high value once fed with GTEE incorporated diets. Significant up-regulation of immune genes indicated the enhancement of immune response at molecular level. The biochemical parameters were found to be significantly decreasing, indicating that the extract had hepato-protective effect and can help to overcome stress. The fish, fed with GTEE incorporated diets, showed resistance against A. hydrophila when compared with the control group. 0.2% GTEE showed the highest post-challenged survival (76.67%). From the present study, it is concluded that GTEE @ 0.2% can be used as potent immunostimulant as a sustainable alternative prophylactic and therapeutic agent in aquaculture.

Inhibition of Biofilm Formation and Virulence Factors of Cariogenic Oral Pathogen Streptococcus mutans by Shikimic Acid

Streptococcus mutans is known as an important oral pathogen causing dental caries, a widespread oral infectious disease. S. mutans synthesize exopolysaccharide (EPS) using glucosyltransferases (Gtfs), resulting in biofilm formation on the tooth surface. Bacterial cells in the biofilms become strongly resistant to a harsh environment, such as antibiotics and host defense mechanisms, making biofilm-based infections difficult to eliminate. Discovering novel antibiofilm agents, especially from natural products, helps to develop effective strategies against this kind of diseases. The present study investigated the inhibitory effect of shikimic acid (SA), one abundant compound derived from Illicium verum extract, on the biofilm formation of S. mutans. We found SA can reduce the EPS synthesized by this oral pathogen and modulate the transcription of biofilm formation related genes, leading to fewer bacterial cells in its biofilm. SA also interacted with cell membrane and membrane proteins, causing damage to bacterial cells. Ex vivo testing of biofilm formation on bovine teeth showed SA strongly decreased the number of S. mutans cells and the number of EPS accumulated on dental enamel surfaces. Moreover, SA exhibits almost no toxicity to human oral cells evaluated by in vitro biocompatibility assay. In conclusion, shikimic acid exhibits remarkable antibiofilm activity against S. mutans and has the potential to be further developed as a novel anticaries agent. IMPORTANCE Natural products are an important and cost-effective source for screening antimicrobial agents. Here, we identified one compound, shikimic acid, from Illicium verum extract, exhibiting antimicrobial activity against S. mutans proliferation. It also inhibits biofilm formation of this bacteria through decreasing Gtf expression and EPS synthesis. Furthermore, this compound exhibits no significant cytotoxicity at its MIC against S. mutans, providing evidence for its clinical application.

Antimicrobial Effect of Epigallocatechin Gallate Against Shewanella putrefaciens ATCC 8071: A Study Based on Cell Membrane and Biofilm

The study was to evaluate the antimicrobial impacts and biofilm influences on epigallocatechin gallate (EGCG) against Shewanella putrefaciens ATCC 8071. The minimum inhibitory concentration (MIC) of EGCG on S. putrefaciens was 160 μg mL^-1. The growth curve exhibited that EGCG had a good antimicrobial activity. EGCG caused damages to the bacterial cell wall and membrane based the intracellular component leakage and cell viability analysis. The damage to the membrane integrity by EGCG has been confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM shows deformation of shape, TEM shows cell membrane and wall damage, and the leakage of cytoplasmic material. The treatment with EGCG at 0.25× and 0.5× MIC resulted in decreased motility and elevated levels of oxidative stress, leading to an increase in biofilm formation. These results demonstrated that EGCG may be used as a natural preservative to reduce S. putrefaciens in fish during cold storage.

Effects of the green tea catechin epigallocatechin-3-gallate on Streptococcus mutans planktonic cultures and biofilms: systematic literature review of in vitro studies

This study aimed at performing a systematic review of the literature on the effects of epigallocatechin-3-gallate (EGCG) on Streptococcus mutans planktonic cultures and biofilms. The selected references demonstrated that EGCG suppresses S. mutans acid production by inhibiting the activity of enzymes such as lactate dehydrogenase and FIF0-ATPase. Regarding virulence factors, one study reported a reduction in soluble and insoluble polysaccharide synthesis, another demonstrated that EGCG inhibited GTase activity, and another showed effects of EGCG on the expression of gtf B, C, and D. The effects of EGCG on S. mutans biofilms were reported only by 2 of the selected studies. Moreover, high variability in effective concentrations and microbial assessment methods were observed. The literature suggests that EGCG has effects against S. mutans planktonic cells viability and virulence factors. However, the literature lacks studies with appropriate biofilm models to evaluate the precise effectiveness of EGCG against S. mutans biofilms.

The Arginine Biosynthesis Pathway of Candida albicans Regulates Its Cross-Kingdom Interaction with Actinomyces viscosus to Promote Root Caries

The cross-kingdom interactions between Candida albicans and Actinomyces viscosus play critical roles in root caries. However, the key pathway by which C. albicans regulates its interactions with A. viscosus is unclear. Here, we first employed 39 volunteers with root caries and 37 caries-free volunteers, and found that the abundances of C. albicans and A. viscosus were significantly increased in the individuals with root caries and showed a strong positive correlation. Their dual-species combination synergistically promoted biofilm formation and root caries in rats. The arginine biosynthesis pathway of C. albicans was significantly upregulated in dual-species biofilms and dental plaques from another 10 root caries volunteers compared with the 10 caries-free volunteers. The exogenous addition of arginine increased the cariogenicity of the dual-species biofilm. The C. albicansARG4, a key gene from the arginine biosynthesis pathway, null mutant failed to promote dual-species biofilm formation and root caries in rats; however, the addition of arginine restored its synergistic actions with A. viscosus. Our results identified the critical roles of the C. albicans arginine biosynthesis pathway in its cross-kingdom interactions with A. viscosus for the first time and indicated that targeting this pathway was a practical way to treat root caries caused by multiple species.

IMPORTANCE Root caries is a critical problem that threatens the oral health of the elderly population. Our results identified the essential roles of the C. albicans arginine biosynthesis pathway in its cross-kingdom interactions with A. viscosus in root caries for the first time and indicated that targeting this pathway was a practical way to treat root caries caused by multiple species.

Antibacterial activities of polyphenols against foodborne pathogens and their application as antibacterial agents

Polyphenols are secondary metabolites produced in higher plants. They are known to possess various functional properties in the human body. Polyphenols also exhibit antibacterial activities against foodborne pathogens. Their antibacterial mechanism is based on inhibiting bacterial biofilm formation or inactivating enzymes. Food-derived polyphenols with such antibacterial activity are natural preservatives and can be used as an alternative to synthetic preservatives that can cause side effects, such as allergies, asthma, skin irritation, and cancer. Studies have reported that polyphenols have positive effects, such as decreasing harmful bacteria and increasing beneficial bacteria in the human gut microbiota. Polyphenols can also be used as natural antibacterial agents in food packaging system in the form of emitting sachets, absorbent pads, and edible coatings. We summarized the antibacterial activities, mechanisms and applications of polyphenols as antibacterial agents against foodborne bacteria.

Benefits and Implications of Resveratrol Supplementation on Microbiota Modulations: A Systematic Review of the Literature

Resveratrol is a polyphenol that has been shown to possess many applications in different fields of medicine. This systematic review has drawn attention to the axis between resveratrol and human microbiota, which plays a key role in maintaining an adequate immune response that can lead to different diseases when compromised. Resveratrol can also be an asset in new technologies, such as gene therapy. PubMed, Cochrane Library, Scopus, Web of Science, and Google Scholar were searched to find papers that matched our topic dating from 1 January 2017 up to 18 January 2022, with English-language restriction using the following Boolean keywords: ("resveratrol" AND "microbio*"). Eighteen studies were included as relevant papers matching the purpose of our investigation. Immune response, prevention of thrombotic complications, microbiota, gene therapy, and bone regeneration were retrieved as the main topics. The analyzed studies mostly involved resveratrol supplementation and its effects on human microbiota by trials in vitro, in vivo, and ex vivo. The beneficial activity of resveratrol is evident by analyzing the changes in the host's genetic expression and the gastrointestinal microbial community with its administration. The possibility of identifying individual microbial families may allow to tailor therapeutic plans with targeted polyphenolic diets when associated with microbial dysbiosis, such as inflammatory diseases of the gastrointestinal tract, degenerative diseases, tumors, obesity, diabetes, bone tissue regeneration, and metabolic syndrome.

Nicotinamide could reduce growth and cariogenic virulence of Streptococcus mutans

Dental caries is among the most prevalent chronic oral infectious diseases. Streptococcus mutans, a major cariogenic bacterial species, possesses several cariogenicity-associated characteristics, including exopolysaccharides (EPS) synthesis, biofilm formation, acidogenicity, and aciduricity. Nicotinamide (NAM), a form of vitamin B3, is a non-toxic, orally available, and inexpensive compound. The present study investigated the inhibitory effects of NAM on the cariogenic virulence factors of S. mutans in vitro and in vivo. NAM inhibited the growth of S. mutans UA159 and the clinical isolates. In addition, there was a decrease in the acid production and acid tolerance ability, as well as biofilm formation and EPS production of S. mutans after NAM treatment. Global gene expression profiling showed that 128 and 58 genes were significantly downregulated and upregulated, respectively, in NAM-treated S. mutans strains. The differentially expressed genes were mainly associated with carbohydrate transport and metabolism, glycolysis, acid tolerance. Moreover, in a rat caries model, NAM significantly reduced the incidence and severity of smooth and sulcal-surface caries in vivo. NAM exhibited good antimicrobial properties against S. mutans, indicating its potential value for antibiofilm and anti-caries applications.

The Application of Small Molecules to the Control of Typical Species Associated With Oral Infectious Diseases

Oral microbial dysbiosis is the major causative factor for common oral infectious diseases including dental caries and periodontal diseases. Interventions that can lessen the microbial virulence and reconstitute microbial ecology have drawn increasing attention in the development of novel therapeutics for oral diseases. Antimicrobial small molecules are a series of natural or synthetic bioactive compounds that have shown inhibitory effect on oral microbiota associated with oral infectious diseases. Novel small molecules, which can either selectively inhibit keystone microbes that drive dysbiosis of oral microbiota or inhibit the key virulence of the microbial community without necessarily killing the microbes, are promising for the ecological management of oral diseases. Here we discussed the research progress in the development of antimicrobial small molecules and delivery systems, with a particular focus on their antimicrobial activity against typical species associated with oral infectious diseases and the underlying mechanisms.

Effect of a Tea Polyphenol on Different Levels of Exposure of Nicotine and Tobacco Extract on Streptococcus mutans Biofilm Formation

Objective: The purpose of this study was to compare the effects of different levels of nicotine and tobacco extract exposure on Streptococcus mutans biofilm formation and the inhibitory effect of the polyphenol epigallocatechin-3 gallate (EGCG) found in green tea. This study addressed the results of biofilm assays with EGCG and varying relative concentrations of nicotine and tobacco extract consistent with primary, secondary and tertiary levels of smoking exposure. Primary smoking exposure to nicotine has been demonstrated to significantly increase biofilm formation, while EGCG has been demonstrated to reduce S. mutans biofilm formation.

Methods:S. mutans was treated with varying levels of nicotine or cigarette smoke condensate (CSC) concentrations (0–32 mg/ml and 0–2 mg/ml, respectively) in Tryptic Soy broth supplemented with 1% sucrose for different lengths of time simulating primary, secondary and tertiary smoking exposure with and without 0.25 mg/ml EGCG. The amount of total growth and biofilm formed was determined using a spectrophotometric crystal violet dye staining assay.

Results: For both nicotine and CSC, primary exposure displayed overall significantly less growth compared to secondary exposure. For nicotine, secondary exposure demonstrated significantly greater growth than tertiary exposure levels. Overall, significantly greater total bacterial growth and biofilm formation in the presence of nicotine and CSC was observed in the absence of EGCG than in the presence of EGCG. However, biofilm growth was not significantly different among different concentrations of CSC.

Conclusion: The results of this study help illustrate that nicotine-induced S. mutans biofilm formation is reduced by the presence of EGCG. This provides further evidence of the potential beneficial properties of polyphenols.

Murburn precepts for lactic-acidosis, Cori cycle, and Warburg effect: Interactive dynamics of dehydrogenases, protons, and oxygen

It is unresolved why lactate is transported to the liver for further utilization within the physiological purview of Cori cycle, when muscles have more lactate dehydrogenase (LDH) than liver. We point out that the answer lies in thermodynamics/equilibriums. While the utilization of NADH for the reduction of pyruvate to lactate can be mediated via the classical mechanism, the oxidation of lactate (with/without the uphill reduction of NAD⁺ ) necessitates alternative physiological approaches. The latter pathway occurs via interactive equilibriums involving the enzyme, protons and oxygen or diffusible reactive oxygen species (DROS). Since liver has high DROS, the murburn activity at LDH would enable the cellular system to tide over the unfavorable energy barriers of the forward reaction (~476 kJ/mol; earlier miscalculated as ~26 kJ/mole). Further, the new mechanism does not necessitate any "smart decision-making" or sophisticated control by/of proteins. The DROS-based murburn theory explains the invariant active-site structure of LDH isozymes and their multimeric nature. The theoretical insights, in silico evidence and analyses of literature herein also enrich our understanding of the underpinnings of "lactic acidosis" (lowering of physiological pH accompanied by lactate production), Warburg effect (increased lactate production at high pO₂ by cancer cells) and approach for cancer therapy.

Small Molecule Compounds, A Novel Strategy against Streptococcus mutans

Dental caries, as a common oral infectious disease, is a worldwide public health issue. Oral biofilms are the main cause of dental caries. Streptococcus mutans (S. mutans) is well recognized as the major causative factor of dental caries within oral biofilms. In addition to mechanical removal such as tooth brushing and flossing, the topical application of antimicrobial agents is necessarily adjuvant to the control of caries particularly for high-risk populations. The mainstay antimicrobial agents for caries such as chlorhexidine have limitations including taste confusions, mucosal soreness, tooth discoloration, and disruption of an oral microbial equilibrium. Antimicrobial small molecules are promising in the control of S. mutans due to good antimicrobial activity, good selectivity, and low toxicity. In this paper, we discussed the application of antimicrobial small molecules to the control of S. mutans, with a particular focus on the identification and development of active compounds and their modes of action against the growth and virulence of S. mutans.

Green tea catechins showed antibacterial activity on streptococcus mutans -An in vitro study

Background

The main bacterial aetiological agents in caries formation are the α-haemolytic Streptococcal species Streptococcus mutans, which has been found to be the initiator of most dental caries. The leaves of Camellia sinensis known as green tea, has properties, such as antibacterial and anti-cariogenic. Epigallocatechin-3-gallate (EGCG) one of the most abundant catechins found in green tea is known to contribute to these effects.

Aim

To evaluate the antibacterial effect of green tea catechins namely EGCG on S. mutans with two different methods at different concentrations.

Objectives

1) To assess the antimicrobial efficacy of EGCG by disc diffusion test at concentrations of 100, 75, and 50 μg/mL. 2) To assess the antimicrobial efficacy of EGCG by Minimum inhibitory concentration (MIC) test at concentrations ranging from 0.2 to 100 μg/mL.

Methodology

Commercially available purest form of green tea polyphenol EGCG was used in the study. Disc diffusion test on agar medium and MIC test was used to determine the susceptibility of the S. mutans to green tea catechins EGCG.

Results

The results of the agar well diffusion method showed that the EGCG extract has shown zones of inhibition against S. mutans at concentrations of 100 μg/mL (28.67 mm), 75 μg/mL (15.33 mm), 50 μg/mL (10.33 mm) while that of MIC test of EGCG extract of concentrations ranging from 0.2 to 100 μg/mL against S. mutans shows that the mean MIC value was 1.07.

Conclusion

Catechins in the tea are potentially anti-cariogenic agents which can reduce bacterial presence in the oral cavity and have the potential to be further used for the preparation of dentifrice and mouthwash.

3, 5-Di-tert-butylphenol combat against Streptococcus mutans by impeding acidogenicity, acidurance and biofilm formation

Streptococcus mutans is a common pathogen present in the oral cavity and it causes dental caries for all aged groups of people, in particular, children. S. mutans have several virulence factors such as acidogenecity, aciduricity, adhesion and biofilm formation. These virulence factors are working together and lead to the development of caries in the tooth surface. The present study aimed to investigate the anticariogenic potential of 3, 5-di-tert-butylphenol (3, 5-DTBP) against S. mutans. 3, 5-DTBP biofilm inhibitory concentration (BIC) was found at 100 µg/ml concentration without any lethal effect on the growth. Moreover, 3, 5-DTBP significantly reduced water soluble and water insoluble glucans production, in concurrence with downregulation of gtfBC genes. Moreover, acidogenicity associated virulence factors such as lactate dehydrogenase and enolase enzymatic production was arrested upon 3, 5-DTBP treatment. In addition, 3, 5-DTBP greatly reduced acidtolerance ability through impedes of F₁F₀-ATPase. Gene expression analysis unveiled the downregulation of gtfB, gtfC, gtfD, vicRK, comDE, gbpB, smu0630 and relA upon 3, 5-DTBP treatment. The present study paves the way for exhibiting 3, 5-DTBP as a promising therapeutic agent to control S. mutans infections.

Vegetal Compounds as Sources of Prophylactic and Therapeutic Agents in Dentistry

Dental pathology remains a global health problem affecting both children and adults. The most important dental diseases are dental caries and periodontal pathologies. The main cause of oral health problems is overpopulation with pathogenic bacteria and for this reason, conventional therapy can often be ineffective due to bacterial resistance or may have unpleasant side effects. For that reason, studies in the field have focused on finding new therapeutic alternatives. Special attention is paid to the plant kingdom, which offers a wide range of plants and active compounds in various pathologies. This review focused on the most used plants in the dental field, especially on active phytocompounds, both in terms of chemical structure and in terms of mechanism of action. It also approached the in vitro study of active compounds and the main types of cell lines used to elucidate the effect and mechanism of action. Thus, medicinal plants and their compounds represent a promising and interesting alternative to conventional therapy.

Anti-vibrio and immune-enhancing activity of medicinal plants in shrimp: A comprehensive review

Disease epidemics in shrimp aquaculture increase apace with the development of aquaculture systems throughout the world. The disease caused by Vibrio spp. (vibriosis) is considered the most devastating, which has made it the most feared bacterial disease in the shrimp sector. In aquaculture, several strategies have already been applied to control Vibrio strains, including chemicals, probiotics, antibiotics, natural products from plants, including plant oils; hence, there has been considerable attention for using plants in shrimp aquaculture to provide sustainable, eco-friendly and safe compounds, such as alkaloids, saponins, terpenoids and flavonoids for replacing chemical compounds and antibiotics in current aquaculture. Medicinal plants may also have immunostimulating activity, increase growth and resistance in shrimps. The present paper aims to review the inhibition of Vibrio spp. in shrimp by medicinal plants, using both in vitro or/and in vivo techniques. Several medicinal plants appear capable of inhibiting growth of Vibrio pathogens outside living shrimp or in the body of shrimp, through enhancing growth and immune capacity when shrimps are fed or injected with them. In the current review Gracilaria spp. (Gracilariaceae family) and Sargassum spp. (family Sargassaceae) have been used most for in vitro and in vivo experiments. Among the terrestrial plants, Eucalyptus camaldulensis, Psidium guajava, Rhodomyrtus tomentosa, and Syzygium cumini (Myrtaceae family) had significant activity against Vibrio.