Concentration-Dependent Multi-Potentiality of L-Arginine: Antimicrobial Effect, Hydroxyapatite Stability, and MMPs Inhibition.

This study's objective was to examine L-arginine (L-arg) supplementation's effect on mono-species biofilm (Streptococcus mutans/Streptococcus sanguinis) growth and underlying enamel substrates. The experimental groups were 1%, 2%, and 4% arg, and 0.9% NaCl was used as the vehicle control. Sterilised enamel blocks were subjected to 7-day treatment with test solutions and S. mutans/S. sanguinis inoculum in BHI. Post-treatment, the treated biofilms stained for live/dead bacterial cells were analysed using confocal microscopy. The enamel specimens were analysed using X-ray diffraction crystallography (XRD), Raman spectroscopy (RS), and transmission electron microscopy (TEM). The molecular interactions between arg and MMP-2/MMP-9 were determined by computational molecular docking and MMP assays. With increasing arg concentrations, bacterial survival significantly decreased (p < 0.05). The XRD peak intensity with 1%/2% arg was significantly higher than with 4% arg and the control (p < 0.05). The bands associated with the mineral phase by RS were significantly accentuated in the 1%/2% arg specimens compared to in other groups (p < 0.05). The TEM analysis revealed that 4% arg exhibited an ill-defined shape of enamel crystals. Docking of arg molecules to MMPs appears feasible, with arg inhibiting MMP-2/MMP-9 (p < 0.05). L-arginine supplementation has an antimicrobial effect on mono-species biofilm. L-arginine treatment at lower (1%/2%) concentrations exhibits enamel hydroxyapatite stability, while the molecule has the potential to inhibit MMP-2/MMP-9.

Novel Amides Derivative with Antimicrobial Activity of Piper betle var. nigra Leaves from Indonesia.

Piper betle var. nigra is a tropical plant closely related to the common piper. P. betle has also been dubbed a promising source of natural antioxidants in herbal health products, antibacterial, antifungal, antimalarial, cytotoxic activity against the cancer cell lines K562 and HL-60, and antileishmanial. The aim of this study to observation Antimicrobial activity and isolation of chemical compound. The antimicrobial activity of P. betle extract was performed by well diffusion method against two oral pathogenic bacteria (Streptococcus mutans and Streptococcus sanguinis) and opportunistic pathogenic yeast (Candida albicans). The inoculum (bacterial and yeast suspension) was prepared from a 24-h culture on NB for bacterial suspension and on TSB for yeast suspension. Extraction and isolation using various method of chromatography. Isolated compounds were characterized by spectroscopic means. Our study showed antimicrobial activity from crude ethanol extract of leaves P. betle L. var. nigra against two oral pathogenic bacteria and opportunistic pathogenic yeast with concentration 0.5% and 1%. The first report of two new amides derivatives, piperenamide A (1) and piperenamide B (2) in P. betle L. var. nigra.

Potential Fatty Acid as Antibacterial Agent Against Oral Bacteria of Streptococcus mutans and Streptococcus sanguinis from Basil (Ocimum americanum): In vitro and In silico Studies.

BACKGROUND: Streptococcus mutans and Streptococcus sanguinis are Gram-positive bacteria that cause dental caries. MurA enzyme acts as a catalyst in the formation of peptidoglycan in bacterial cell walls, making it ideal as an antibacterial target. Basil (Ocimum americanum) is an edible plant that is diverse and has been used as a herbal medicine for a long time. It has been reported that basil has a pharmacological effect as well as antibacterial activity. The purpose of this study was to identify antibacterial compounds in O. americanum and analyze their inhibition activity on MurA enzyme. METHODS: Fresh leaves from O. americanum were extracted with n-hexane and purified by a combination of column chromatography on normal and reverse phases together with in vitro bioactivity assay against S. mutans ATCC 25175 and S. sanguinis ATCC 10556, respectively, while in silico molecular docking simulation of lauric acid (1) was conducted using PyRx 0.8. RESULTS: The structure determination of antibacterial compound by spectroscopic methods resulted in an active compound lauric acid (1). The in vitro evaluation of antibacterial activity in compound 1 showed Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values of 78.13 and 156.3 ppm and 1250 and 2500 ppm against S. sanguinis and S. mutans, respectively. Further analysis and in silico evaluation determined lauric acid (1) as MurA Enzyme inhibitor. Lauric acid (1) showed a binding affinity of -5.2 Kcal/mol, which was higher than fosfomycin. CONCLUSION: Lauric acid showed the potential as a new natural antibacterial agent through MurA inhibition in bacterial cell wall biosynthesis.

Dimethylated acylphloroglucinol meroterpenoids with anti-oral-bacterial and anti-inflammatory activities from Hypericum elodeoides.

Acylphloroglucinol meroterpenoids are adducts of the acylphloroglucinol unit and polyprenylated fragments (terpenoids) with attractive structures and bioactivities. During study of the medicinal molecules of the genus Hypericum, the first example of dimethylated acylphloroglucinol meroterpenoids with pyran-fused 6/6/6 tricyclic skeletons ((+)/(-)-elodeoidols A-F (1-6)), along with three biogenetical homologues (7-9) were isolated from the herbaceous plant of Hypericum elodeoides. Their structures including absolute configurations were then identified by nuclear magnetic resonance (NMR), high resolution electrospray ionization mass spectroscopy (HRESIMS), electronic circular dichroism (ECD) analysis and calculations. The monoterpene moiety of 1-6 were cyclized as two cyclohexanes and fused with a dimethylated acylphloroglucinol unit through an additional ether linkage, which led to an interesting pyran-fused linear or angle type 6/6/6 tricyclic skeleton. Compounds 5, 8 and 9 showed preferable antibacterial activities against three oral bacteria, among the MIC value of (+)-5 was 6.25 µg/ml; Compounds 3, 7 and 8 exhibited significant NO inhibitory activity against LPS induced RAW264.7 cells (IC50: 10.39 ± 0.49 ~ 34.25 ± 2.32 µM).

Potential Allylpyrocatechol Derivatives as Antibacterial Agent Against Oral Pathogen of S. sanguinis ATCC 10,556 and as Inhibitor of MurA Enzymes: in vitro and in silico Study.

BACKGROUND: Streptococcus sanguinis is Gram-positive bacteria that contribute to caries. Many antibacterial agents are resistant against bacteria so that the discovery of new antibacterial agents is a crucial issue. Mechanism of antibacterial agents by disrupting cell wall bacteria is a promising target to be developed. One of the enzymes contributing to the cell wall is MurA enzyme. MurA is an enzyme catalyzing the first step of peptidoglycan biosynthesis in the cell wall formation. Inhibiting MurA is an effective and efficient way to kill the bacteria. Source of bioactive compounds including the antibacterial agent can be found in natural product such as herbal plant. Piper betle L. was reported to contain active antibacterial compounds. However, there is no more information on the antibacterial activity and molecular mechanism of P. betle's compound against S. sanguinis. PURPOSE: The study aims to identify antibacterial constituents of P. betle L. and evaluate their activities through two different methods including in vitro and in silico analysis. MATERIALS AND METHODS: The antibacterial agent was purified by bioactivity-guided isolation with combination chromatography methods and the chemical structure was determined by spectroscopic methods. The in vitro antibacterial activity was evaluated by disc diffusion and dilution methods while the in silico study of a compound binds on the MurA was determined using PyRx program. RESULTS: The antibacterial compound identified as allylpyrocatechol showed inhibitory activity against S. sanguinis with an inhibition zone of 11.85 mm at 1%, together with MIC and MBC values of 39.1 and 78.1 µg/mL, respectively. Prediction for molecular inhibition mechanism of allylpyrocatechols against the MurA presented two allylpyrocatechol derivatives showing binding activity of -5.4, stronger than fosfomycin as a reference with the binding activity of -4.6. CONCLUSION: Two allylpyrocatechol derivatives were predicted to have a good potency as a novel natural antibacterial agent against S. sanguinis through blocking MurA activity that causes disruption of bacterial cell wall.

Inhibitory Effects of Lingonberry Extract on Oral Streptococcal Biofilm Formation and Bioactivity.

Phenolic compounds in fruits such as cranberries have been shown to promote a number of biological activities. The purpose of this study was to investigate the effects of polyphenolic compound-containing lingonberry extract on oral streptococci and compare them with the known anti-cariogenic activity of cranberries. Water-soluble and polyphenol-rich fractions (Fractions I and II, respectively) were isolated from cranberries and lingonberries. The effects of those fractions on the biofilm formation ability and bioactivity of Streptococcus mutans MT8148R, Streptococcus sobrinus 6715, and Streptococcus sanguinis ATCC 10556 were then evaluated. Cranberry or lingonberry Fraction II (at 0.5-1 mg/ml) significantly reduced biofilm formation by S. mutans, S. sobrinus, and S. sanguinis. In contrast, cranberry or lingonberry Fraction I (at 0.5-2 mg/ml) increased biofilm formation by S. mutans and S. sobrinus, but not by S. sanguinis. Fractions I and II (at 1-2 mg/ml) also reduced the bioactivity of S. mutans, while Fraction II (at 0.5 mg/ml) enhanced the bioactivity of all tested strains. The results revealed that lingonberries contained a larger amount of polyphenol than cranberries and that they showed almost the same level of activity against the biofilm formation ability and bioactivity of oral streptococci. This indicates that polyphenol-rich lingonberry fraction offers a promising natural food derivative for prevention of dental caries.

Antibacterial Activity of Homeopathic Medications Lycopodium clavatum and Arsenicum album Against Periodontal Bacteria / Evaluación antibacteriana de los medicamentos homeopáticos sobre bacterias periodontales

Abstract There are several controversies regarding the efficacy of homeopathic substances; however, these remedies are used in many countries for the treatment of various pathological conditions. The purpose of this study was to evaluate the in vitro antibacterial activity of two homeopathic tinctures Arsenicum album (mineral extract) and Lycopodium clavatum (plant extract) on the periodontal bacteria Actinomyces israelii, Streptococcus sanguinis, Prevotella intermedia, Aggregatibacter actinomycetemcomitans and Phorphyromonas gingivalis (P. gingivalis). Materials and methods: Equal numbers of bacteria were seeded on agar plates containing enriched media with the homeopathic solutions at 1dH and 1cH dilutions. After 7 days of incubation under anaerobic conditions, colony forming units (CFUs) were counted. The antibacterial effect was calculated based on the total number of CFUs observed on non-tincture containing agar, and on the tincture containing plates. Results: No visible growth of any of the strains was observed on the plates containing Arsenicum album at any of the dilutions tested. In contrast, when Lycopodium clavatum at 1cH dilution was tested, only P. gingivalis was susceptible to this compound. Conclusions: The results suggest that the mineral extract tincture had a greater antibacterial activity than the plant extract tincture, also Lycopodium clavatum preparation could be an effective inhibitor of periodontal pathogens bacteria such as P. gingivalis.

Resumen Se necesita un mayor número de estudios in vitro e in vivo para validar estos resultados.

Comparative effect of photodynamic therapy on separated or mixed cultures of Streptococcus mutans and Streptococcus sanguinis.

Antimicrobial photodynamic therapy (aPDT) has shown to exert a bactericidal effect against Streptococcus sanguinis and Streptococcus mutans. However, this efficacy has been reported for either type of bacteria separately. Bacterial suspensions of both strains, separately or together, were treated with concentrations of methylene blue (MB) and rose bengal (RB). Suspensions were irradiated with a light-emitting diode lamp (λ center at 625nm for MB and λ center at 515nm for RB) using a fluence of 18J/cm2. RB-aPDT at concentrations of 0.16-0.62 and 0.16-0.31µg/mL, and MB-aPDT at concentrations of 0.62-1.25 and 0.31-1.25µg/mL inhibited the growth of S. mutans and S. sanguinis respectively by 6 log10. In suspensions of both strains together, the same 6 log10 reduction in bacterial growth was achieved using the same concentrations of each photosensiziser. In conclusion, RB-aPDT and MB-aPDT appear to exert the same bactericidal effect against suspensions of S. sanguinis and S. mutans either for single strain treatment or for samples constituted by both bacteria mixed together. RB shows to be slightly more efficient than MB.

Antimicrobial efficacy of the combinations of Acacia nilotica,Murrayakoenigii (Linn.) Sprengel, Eucalyptus, and Psidiumguajava on primary plaque colonizers: An in vitro study.

BACKGROUND: The rise in disease incidence, increased resistance of pathogenic bacteria to currently used antibiotics and chemotherapeutics, opportunistic infections in immunocompromised individuals, and financial considerations in developing countries necessitates alternate preventive and treatment strategies for oral diseases. OBJECTIVE: The objective of the study is to assess the antimicrobial efficacy of triple and quadruple combinations of Acacia nilotica (AN), Murraya koenigii (Linn.) (MKL) Sprengel, Eucalyptus (Euca), and Psidium guajava (PS) on primary plaque colonizers. MATERIALS AND METHODS: The phytochemicals in four plants were extracted using Soxhlet apparatus. The dried extracts were diluted with dimethyl sulfoxide (DMSO) to prepare stock solutions (100 mg/ml) of each plant. The triple and quadruple combinations were prepared after mixing equal quantities of stock solutions from each plant extracts. The antimicrobial efficacy testing was done on Streptococcus mutans, Streptococcus sanguis, and Streptococcus salivarius using agar well diffusion method. Chlorhexidine of 0.2% composition and DMSO were used as positive and negative controls, respectively. The mean diameter of inhibition zone between different categories was compared using one-way analysis of variance. RESULTS: The combination of AN + MKL Sprengel + Euca + PS produced the highest mean diameter of inhibition zone (23.5 ± 2.17 mm) against S. mutans. The combination of AN + MKL Sprengel + Euca produced the maximum antimicrobial efficacy against S. sanguis (19.83 ± 1.33). CONCLUSION: All the triple and quadruple combinations of the plant extracts offered antimicrobial benefits either superior or comparable to 0.2% chlorhexidine against S. mutans, S. sanguis, and S. salivarius.

Anti-plaque effect of a synergistic combination of green tea and Salvadora persica L. against primary colonizers of dental plaque.

OBJECTIVE: Green tea (Gt), leafs of Camellia sinensis var. assamica, is widely consumed as healthy beverage since thousands of years in Asian countries. Chewing sticks (miswak) of Salvadora persica L. (Sp) are traditionally used as natural brush to ensure oral health in developing countries. Both Gt and Sp extracts were reported to have anti-bacterial activity against many dental plaque bacteria. However, their combination has never been tested to have anti-bacterial and anti-adherence effect against primary dental plaque colonizers, playing an initial role in the dental plaque development, which was investigated in this study. METHODS: Two-fold serial micro-dilution method was used to measure minimal inhibitory concentration (MIC) of aqueous extracts of Gt, Sp and their combinations. Adsorption to hexadecane was used to determine the cell surface hydrophobicity (CSH) of bacterial cells. Glass beads were used to mimic the hard tissue surfaces, and were coated with saliva to develop experimental pellicles for the adhesion of the primary colonizing bacteria. RESULTS: Gt aqueous extracts exhibited better anti-plaque effect than Sp aqueous extracts. Their combination, equivalent to 1/4 and 1/2 of MIC values of Gt and Sp extracts respectively, showed synergistic anti-plaque properties with fractional inhibitory concentration (FIC) equal to 0.75. This combination was found to significantly reduce CSH (p<0.05) and lower the adherence ability (p<0.003) towards experimental pellicles. CONCLUSION: Combination between Gt and Sp aqueous extracts exhibited synergistic anti-plaque activity, and could be used as a useful active agent to produce oral health care products.

In vitro effect photodynamic therapy with differents photosensitizers on cariogenic microorganisms.

BACKGROUND: Antimicrobial photodynamic therapy has been proposed as an alternative to suppress subgingival species. This results from the balance among Streptococcus sanguis, Streptococcus mutans and Candida albicans in the dental biofilm. Not all the photosensitizers have the same photodynamic effect against the different microorganims. The objective of this study is to compare in vitro the photodynamic effect of methylene blue (MB), rose Bengal (RB) and curcumin (CUR) in combination with white light on the cariogenic microorganism S. mutans, S. sanguis and C. albicans. RESULTS: Photodynamic therapy with MB, RB and CUR inhibited 6 log 10 the growth of both bacteria but at different concentrations: 0.31-0.62 µg/ml and 0.62-1.25 µg/ml RB were needed to photoinactivate S. mutans and S. sanguis, respectively; 1.25-2.5 µg/ml MB for both species; whereas higher CUR concentrations (80-160 µg/ml and 160-320 µg/ml) were required to obtain the same reduction in S. mutans and S. sanguis viability respectively. The minimal fungicidal concentration of MB for 5 log10 CFU reduction (4.5 McFarland) was 80-160 µg/ml, whereas for RB it ranged between 320 and 640 µg/ml. For CUR, even the maximum studied concentration (1280 µg/ml) did not reach that inhibition. Incubation time had no effect in all experiments. CONCLUSIONS: Photodynamic therapy with RB, MB and CUR and white light is effective in killing S. mutans and S. sanguis strains, although MB and RB are more efficient than CUR. C. albicans required higher concentrations of all photosensitizers to obtain a fungicidal effect, being MB the most efficient and CUR ineffective.

Antibacterial activity of berry juices, an in vitro study.

OBJECTIVE: The aim of the present study was to evaluate in vitro antibacterial activities of blackcurrant and sea buckthorn juices on bacteria associated with gingival inflammation. MATERIALS AND METHODS: The growth of selected bacteria (Streptococcus mitis, Streptococcus mutans, Streptococcus sanguinis, Streptococcus gordonii, Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa) was studied in vitro on agar plates. The content of phenols in the different extracts was measured with HPLC-ESI-MS. RESULTS: The spectrometric analysis identified that the highest level of the single phenols studied was found for ferulic acid (113 µg/ml) in blackcurrant juice. Sea buckthorn contained low levels of selected phenols. Total bacterial inhibition for all bacterial species studied was found at 20% berry juice concentration with pH varying between 4.1-5.4. CONCLUSIONS: The present study identified that in vitro bacterial growth on agar plates was inhibited by blackcurrant and sea buckthorn juices and that low juice pH explains bacterial in vitro growth. This may have clinical implications in biofilm development, reducing the risks for both tooth decay and gingivitis.

Action of essential oils from Brazilian native and exotic medicinal species on oral biofilms.

BACKGROUND: Essential oils (EO) obtained from twenty medicinal and aromatic plants were evaluated for their antimicrobial activity against the oral pathogens Candida albicans, Fusobacterium nucleatum, Porphyromonas gingivalis, Streptococcus sanguis and Streptococcus mitis. METHODS: The antimicrobial activity of the EO was evaluates by microdilution method determining Minimal Inhibitory Concentration. Chemical analysis of the oils compounds was performed by Gas chromatography-mass spectrometry (CG-MS). The most active EO were also investigated as to their actions on the biolfilm formation. RESULTS: The most of the essential oils (EO) presented moderate to strong antimicrobial activity against the oral pathogens (MIC--Minimal Inhibitory Concentrations values between 0.007 and 1.00 mg/mL). The essential oil from Coriandrum sativum inhibited all oral species with MIC values from 0.007 to 0.250 mg/mL, and MBC/MFC (Minimal Bactericidal/Fungicidal Concentrations) from 0.015 to 0.500 mg/mL. On the other hand the essential oil of C. articulatus inhibited 63.96% of S. sanguis biofilm formation. Through Scanning Eletronic Microscopy (SEM) images no changes were observed in cell morphology, despite a decrease in biofilm formation and changes on biofilm structure. Chemical analysis by Gas Chromatography-Mass Spectrometry (GC-MS) of the C. sativum essential oil revealed major compounds derivatives from alcohols and aldehydes, while Cyperus articulatus and Aloysia gratissima (EOs) presented mono and sesquiterpenes. CONCLUSIONS: In conclusion, the crude oil from C. articulatus exhibited the best results of antimicrobial activity e ability to control biofilm formation. The chemical analysis showed the presence of terpenes and monoterpenes such as a-pinene, a-bulnesene and copaene. The reduction of biofilms formation was confirmed from SEM images. The results of this research shows a great potential from the plants studied as new antimicrobial sources.

Antibacterial efficacy of exogenous nitric oxide on periodontal pathogens.

Current treatments for periodontitis (e.g., scaling/root planing and chlorhexidine) have limited efficacy since they fail to suppress microbial biofilms satisfactorily over time, and the use of adjunctive antimicrobials can promote the emergence of antibiotic-resistant organisms. Herein, we report the novel application of nitric oxide (NO)-releasing scaffolds (i.e., dendrimers and silica particles) as anti-periodontopathogenic agents. The effectiveness of macromolecular NO release was demonstrated by a 3-log reduction in periodontopathogenic Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis viability. In contrast, Streptococcus mutans and Streptococcus sanguinis, caries-associated organisms, were substantially less sensitive to NO treatment. Both dendrimer- and silica-based NO release exhibited substantially less toxicity to human gingival fibroblasts at concentrations necessary to eradicate periodontopathogens than did clinical concentrations of chlorhexidine. These results suggest the potential utility of macromolecular NO-release scaffolds as a novel platform for the development of periodontal disease therapeutics.

In-office bleaching gel with 35% hydrogen peroxide enhanced biofilm formation of early colonizing streptococci on human enamel.

OBJECTIVES: To compare the effects of 25% and 35% hydrogen peroxide in-office bleaching systems on surface roughness and streptococcal biofilm formation on human enamel. METHODS: Enamel specimens (3mm×3mm×2mm, n=162) from human permanent teeth were randomly divided into 3 treatment groups (n=54 each): (1) control, (2) bleached with 25% hydrogen peroxide (Zoom2™), and (3) bleached with 35% hydrogen peroxide (Beyond™). The enamel surface roughness was measured by a profilometer before and after treatments. Subsequently, the treated enamel specimens were randomly placed into 3 subgroups (n=18 each) and incubated with: (1) trypticase soy broth control, (2) Streptococcus mutans culture and (3) Streptococcus sanguinis culture for 24h. Biofilm formation was quantified by crystal violet staining. The biofilm structure on three specimens from each group was visualized by scanning electron microscopy. Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests with Bonferroni corrections. Significance level was set at p<0.05. RESULTS: Both bleaching systems significantly reduced enamel surface roughness comparing to the control group (p<0.001), but there was no difference between the two treatment groups. Remarkably, S. sanguinis biofilm formation was significantly higher on enamel specimens bleached with 35% hydrogen peroxide than other treatments (p<0.001), but was lower on those bleached with 25% hydrogen peroxide (p<0.001). In contrast, no difference in S. mutans biofilm formation was observed among the three treatment groups. CONCLUSION: Both 25% and 35% hydrogen peroxide caused similar degrees of reduction in enamel surface roughness. Nevertheless, bleaching with 35% hydrogen peroxide appeared to markedly promote S. sanguinis biofilm formation. CLINICAL SIGNIFICANCE: The increase of early colonizer biofilm raised concerns over adverse effects of in-office bleaching on plaque formation. This should be further investigated in vivo and efficient plaque control should be emphasized after bleaching with high concentrations of hydrogen peroxide.

Systematic screening of plant extracts from the Brazilian Pantanal with antimicrobial activity against bacteria with cariogenic relevance.

This study proposes a bioprospection methodology regarding the antimicrobial potential of plant extracts against bacteria with cariogenic relevance. Sixty extracts were obtained from ten plants--(1) Jatropha weddelliana, (2) Attalea phalerata, (3) Buchenavia tomentosa, (4) Croton doctoris, (5) Mouriri elliptica, (6) Mascagnia benthamiana, (7) Senna aculeata, (8) Unonopsis guatterioides, (9) Allagoptera leucocalyx and (10) Bactris glaucescens--using different extraction methods - (A) 70° ethanol 72 h/25°C, (B) water 5 min/100°C, (C) water 1 h/55°C, (D) water 72 h/25°C, (E) hexane 72 h/25°C and (F) 90° ethanol 72 h/25°C. The plants were screened for antibacterial activity at 50 mg/ml using the agar well diffusion test against Actinomyces naeslundii ATCC 19039, Lactobacillus acidophilus ATCC 4356, Streptococcus gordonii ATCC 10558, Streptococcus mutans ATCC 35688, Streptococcus sanguinis ATCC 10556, Streptococcus sobrinus ATCC 33478 and Streptococcus mitis ATCC 9811. The active extracts were tested to determine their minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), cytotoxicity and chemical characterization. Forty-seven extracts (78%) were active against at least one microorganism. Extract 4A demonstrated the lowest MIC and MBC for all microorganisms except S. gordonii and the extract at MIC concentration was non-cytotoxic. The concentrated extracts were slightly cytotoxic. Electrospray ionization with tandem mass spectrometry analyses demonstrated that the extract constituents coincided with the mass of the terpenoids and phenolics. Overall, the best results were obtained for extraction methods A, B and C. The present work proved the antimicrobial activity of several plants. Particularly, extracts from C. doctoris were the most active against bacteria involved in dental caries disease.

Antibacterial effect of Iranian green-tea-containing mouthrinse vs chlorhexidine 0.2%: an in vitro study.

PURPOSE: Considering the antioxidant, anti-inflammatory and antimicrobial properties of green tea, this study aimed to evaluate the antibacterial effect of mouthrinses containing green tea extract vs 0.2% chlorhexidine on selected microorganisms in vitro. MATERIALS AND METHODS: The antibacterial activity of both mouthrinses and the pure green tea extract was assessed by using disk diffusion and the minimal inhibitory concentration (MIC) methods against five microorganisms: Streptococcus mutans, Streptococcus sanguis, Enterococcus faecalis, Pseudomonas aerogenosa and Escherichia coli. Growth inhibition zones were measured in mm after 24 h of incubation at 37°C. The two mouthrinses were assessed at concentrations of 1, 2, 4, 8, 16, 32, 64, 128, 256 and 512 mg/ml to determine the MIC, which was interpreted as the lowest concentration of the agent that completely inhibited the growth of the test species. RESULTS: 0.2% chlorhexidine produced a larger zone of growth inhibition than did the mouthrinse made of green tea extract (P < 0.01). Paradoxically, the growth inhibition zones of the tested bacteria were significantly larger in pure extract of green tea than in 0.2% chlorhexidine (P < 0.01). The chlorhexidine mouthrinse inhibited the growth of all tested species and exhibited significantly lower MICs than did the green tea mouthrinse (P < 0.01). CONCLUSIONS: Even though the mouthrinse made with green tea extract presented an in vitro antimicrobial activity inferior to 0.2% chlorhexidine, the pure extract had considerable bactericidal effect.

Microcalorimetric determination of the effects of amoxicillin, metronidazole, and their combination on in vitro biofilm.

BACKGROUND: The mechanism of action of adjuvant antibiotic therapy in the treatment of peri-implantitis is not well understood. The aim of this study is to investigate antibiotic susceptibility of an in vitro biofilm by isothermal microcalorimetry (IMC). METHODS: Titanium disks containing a 72-hour three-species biofilm (Streptococcus sanguinis DSM20068, Fusobacterium nucleatum ATCC10953, and Porphyromonas gingivalis DSM20709) were placed in a series of IMC ampoules with nutrient agar supplemented with increasing concentrations of amoxicillin, metronidazole, or their combination and incubated anaerobically for 10 days. Lag time and maximum growth rate were determined from continuous heat-flow recordings of metabolic activity. To validate the IMC biofilm results, adherent S. sanguinis and P. gingivalis were incubated anaerobically in medium supplemented with antibiotics at 37°C for 24 hours, and their vitality was determined by live/dead staining, conventional culturing, and IMC. RESULTS: In all biofilm samples incubated with antibiotics, a prolonged lag phase was observed compared with controls (P <0.05). Maximum growth rate was significantly lower for samples treated with either amoxicillin or metronidazole compared with controls (P <0.05). Combining the antibiotics did not improve this effect. Concentrations exceeding 10 times the minimum inhibitory concentration completely inhibited the growth of adherent S. sanguinis and P. gingivalis, whereas lower concentrations resulted in only a delay in the lag phase. A poor correlation was observed between live/dead staining and conventional culturing. CONCLUSIONS: IMC gives new evidence about antibiotic effects on oral biofilms and is more informative than conventional culture and live/dead assays. The combination of antibiotics was found to be more efficient than metronidazole alone; however, only minor differences in growth inhibition were detected compared with amoxicillin alone.

Antibacterial effect of different concentrations of garlic (Allium sativum) extract on dental plaque bacteria.

BACKGROUND: Allium sativum, commonly known as garlic, exhibits antibacterial effects against a wide range of bacteria. AIM: The objective of this in vitro study was to assess the antibacterial effect of different concentrations of garlic extract against human dental plaque microbiota. MATERIALS AND METHODS: Antibacterial activities of four different concentrations of garlic extract (5%, 10%, 20%, and 100%) were evaluated against Streptococcus mutans, Streptococcus sanguis, Streptococcus salivarius, Pseudomonas aeruginosa, and lactobacillus spp. using the disk diffusion method. Papers soaked in 0.2% concentration chlorhexidine gluconate and saline were used as positive and negative controls, respectively. The data were subjected to one-way ANOVA and the Tukey multiple comparisons test at a 5% significance level. RESULTS: All bacterial strains were inhibited by all test materials. The inhibition zones of the different concentrations of garlic extract were not significantly different for S. mutans, S. sanguis, and S. salivarius. For P. aeruginosa and lactobacillus spp. the inhibition zones of 5%, 10% and 20% concentrations were not significantly different from one another, but they were significantly more than that of the 100% extract. CONCLUSION: The 5%, 10%, 20%, and 100% concentrations of garlic extract had similar effects, so further studies seem to be indicated on the usefulness of the 5% extract.

A comparative evaluation of the antibacterial efficacy of honey in vitro and antiplaque efficacy in a 4-day plaque regrowth model in vivo: preliminary results.

BACKGROUND: Honey has a potent broad-spectrum antibacterial action that may make it suitable for "anti-infective" treatment of periodontal disease. The aims of this study are as follows: 1) to evaluate the antibacterial efficacy of honey against oral bacteria and compare the same with 0.2% chlorhexidine; and 2) to compare antiplaque efficacy in vivo with chlorhexidine. METHODS: The study was conducted in two parts. In the in vitro part, the inhibitory effects of three test agents, 0.2% chlorhexidine gluconate, honey mouthwash, and saline, against six oral bacteria at concentrations of 1, 2, 4, 8, 16, 32, 64, 128, 256, and 512 µg/mL were tested in duplicate. The minimum inhibitory concentration (MIC) was set as the lowest concentration of the agent that completely inhibited the growth of the test species. The in vivo part consisted of a double-masked parallel clinical trial based on a 4-day plaque regrowth model. Sixty-six volunteers, 20 to 24 years of age, participated in the study, and the plaque scores were compared at baseline and at the end of 4 days. The Kruskal-Wallis test was used for significance, and the Mann-Whitney U test was used for pairwise comparison of the groups. The mean plaque scores were 1.77 ± 0.86, 1.64 ± 0.90, and 3.27 ± 0.83 for groups 1, 2, and 3, respectively. RESULTS: The honey mouthrinse effectively inhibited the six tested microorganisms. The chlorhexidine gluconate rinse had the lowest MICs compared with honey and saline rinses for all test species examined. The in vivo results revealed that plaque formation was inhibited/reduced by chlorhexidine and honey rinses. CONCLUSION: Honey has antibacterial action against tested oral microorganisms and also has antiplaque action.