Essential Oil from Psidium cattleianum Sabine (Myrtaceae) Fresh Leaves: Chemical Characterization and in vitro Antibacterial Activity Against Endodontic Pathogens

Abstract Endodontic infections result from oral pathogenic bacteria which reach and infect dental pulp, as well as surrounding tissues, through cracks, unrepaired caries and failed caries restorations. This study aims to determine the chemical composition of essential oil from Psidium cattleianum leaves (PC-EO) and to assess its antibacterial activity against endodontic bacteria. Antibacterial activity of PC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method on 96-well microplates. Bacteria Porphyromonas gingivalis (MIC = 20 µg/mL), Prevotella nigrescens (MIC = 62.5 µg/mL), Fusobacterium nucleatum (MIC = 12.5 µg/mL), Actinomyces naeslundii (MIC = 50 µg/mL), Bacteroides fragilis (MIC = 12.5 µg/mL), Aggregatibacter actinomycetemcomitans (MIC = 6.25 µg/mL) and Peptostreptococcus anaerobius (MIC = 62.5 µg/mL) were evaluated and compared to chlorhexidine dihydrochloride (CDH), the positive control. PC-EO was obtained by hydrodistillation with the use of a Clevenger-type apparatus whereas its chemical composition was analyzed by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Viridiflorol (17.9%), β-caryophyllene (11.8%), 1,8-cineole (10.8%) and β-selinene (8.6%) were the major constituents found in PC-EO, which exhibited high antibacterial activity against all endodontic pathogens under investigation. Therefore, PC-EO, a promising source of bioactive compounds, may provide therapeutic solutions for the field of endodontics.

Antimicrobial Effects of Mastic Extract Against Oral and Periodontal Pathogens.

BACKGROUND: Various antimicrobial agents are widely used in the therapy of oral inflammatory diseases. However, their side effects and the appearance of drug resistance justify research on natural antimicrobial agents to target oral pathogens that are safe for the host. In the present study, antimicrobial properties of mastic extract on commensal and pathogenic oral bacteria, as well as its possible cytotoxic effect toward cells of epithelial and mesenchymal origin, were evaluated and compared with the common antimicrobial agents hydrogen peroxide (H2O2) and chlorhexidine digluconate (CHX). METHODS: Oral and periodontal pathogens (Porphyromonas gingivalis, Streptococcus mutans [Sm], Streptococcus oralis, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Prevotella intermedia, and Prevotella nigrescens) were treated with different concentrations of mastic extract, 3% H2O2, and 0.2% CHX, and evaluated with an agar diffusion test. The cytotoxic effect of mastic extract was tested on four cell lines of epithelial and mesenchymal origin (HaCaT, SaOS-2, MC3T3-E1, periodontal ligament [PDL] cells) by neutral red and 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay. RESULTS: Mastic extract led to significantly (P ≤0.016) increased inhibition of the tested periodontal pathogens compared with H2O2. No effect of mastic extract was observed on Sm. Mastic extract showed beneficial effects on cell viability because viability values of tested cells were significantly (P ≤0.016) lower for cells treated with CHX and H2O2 compared with mastic extract-treated cells after stimulation for 2, 4, and 6 hours. CONCLUSION: The present data demonstrate mastic extract's inhibition of periodontal pathogens, as well as beneficial effects on cell viability, compared with H2О2, suggesting that it could be considered an alternative antibacterial agent in the prevention of periodontal disease.

Copaifera reticulata oleoresin: Chemical characterization and antibacterial properties against oral pathogens.

Oral infections such as periodontitis and tooth decay are the most common diseases of humankind. Oleoresins from different copaifera species display antimicrobial and anti-inflammatory activities. Copaifera reticulata is the commonest tree of this genus and grows abundantly in several Brazilian states, such as Pará, Amazonas, and Ceará. The present study has evaluated the chemical composition and antimicrobial potential of the Copaifera reticulata oleoresin (CRO) against the causative agents of tooth decay and periodontitis and has assessed the CRO cytotoxic potential. Cutting edge analytical techniques (GC-MS and LC-MS) aided the chemical characterization of CRO. Antimicrobial assays included determination of the Minimum Inhibitory Concentration (MIC), determination of the Minimum Bactericidal Concentration (MBC), determination of the Minimum Inhibitory Concentration of Biofilm (MICB50), Time Kill Assay, and Checkerboard Dilution. Conduction of XTT assays on human lung fibroblasts (GM07492-A cells) helped to examine the CRO cytotoxic potential. Chromatographic analyses revealed that the major constituents of CRO were ß-bisabolene, trans-α-bergamotene, ß-selinene, α-selinene, and the terpene acids ent-agathic-15-methyl ester, ent-copalic acid, and ent-polyalthic acid. MIC and MBC results ranged from 6.25 to 200 µg/mL against the tested bacteria. The time-kill assay conducted with CRO at concentrations between 50 and 100 µg/mL showed bactericidal activity against Fusobacterium nucleatum (ATCC 25586) and Streptococcus mitis (ATCC 49456) after 4 h, Prevotella nigrescens (ATCC 33563) after 6 h, Porphyromonas gingivalis (ATCC 33277) and Lactobacillus casei (clinical isolate) after 12 h, and Streptococcus salivarius (ATCC 25975) and Streptococcus mutans (ATCC 25175) after 18 h. The fractional inhibitory concentration indexes (FICIs) revealed antagonistic interaction for Lactobacillus casei (clinical isolate), indifferent effect for Porphyromonas gingivalis (ATCC 33277), Fusobacterium nucleatum (ATCC 25586), Prevotella nigrescens (ATCC 33563), and Streptococcus salivarius (ATCC 25975), and additive effect for Streptococcus mutans (ATCC 25175) and Streptococcus mitis (ATCC 49456). Treatment of GM07492-A cells with CRO demonstrated that concentrations up to 39 µg/mL significantly reduced cell viability as compared to the negative control, being IC50 equal to 51.85 ± 5.4 µg/mL. These results indicated that CRO plays an important part in the search for novel sources of agents that can act against oral pathogens.

Antibacterial activity of commercially available plant-derived essential oils against oral pathogenic bacteria.

This work investigated the antibacterial activity of 15 commercially available plant-derived essential oils (EOs) against a panel of oral pathogens. The broth microdilution method afforded the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of the assayed EOs. The EO obtained from Cinnamomum zeylanicum (Lauraceae) (CZ-EO) displayed moderate activity against Fusobacterium nucleatum (MIC and MBC = 125 µg/mL), Actinomyces naeslundii (MIC and MBC = 125 µg/mL), Prevotella nigrescens (MIC and MBC = 125 µg/mL) and Streptococcus mutans (MIC = 200 µg/mL; MBC = 400 µg/mL). (Z)-isosafrole (85.3%) was the main chemical component of this oil. We did not detect cinnamaldehyde, previously described as the major constituent of CZ-EO, in specimens collected in other countries.

Prevalence of ß-lactamase-producing bacteria in human periodontitis.

BACKGROUND AND OBJECTIVE: Beta-lactam antibiotics prescribed in periodontal therapy are vulnerable to degradation by bacterial ß-lactamases. This study evaluated the occurrence of ß-lactamase-positive subgingival bacteria in chronic periodontitis subjects of USA origin, and assessed their in vitro resistance to metronidazole at a breakpoint concentration of 4 µg/mL. MATERIAL AND METHODS: Subgingival plaque specimens from deep periodontal pockets with bleeding on probing were removed from 564 adults with severe chronic periodontitis before treatment. The samples were transported in VMGA III and then plated onto: (i) nonselective enriched Brucella blood agar (EBBA) and incubated anaerobically for 7 d; and (ii) selective trypticase soy-bacitracin-vancomycin (TSBV) and incubated for 3 d in air + 5% CO2 . At the end of the incubation periods, the bacterial test species were identified and quantified. Specimen dilutions were also plated onto EBBA plates supplemented with 2 µg/mL of amoxicillin, a combination of 2 µg/mL of amoxicillin plus 2 µg/mL of the ß-lactamase inhibitor clavulanic acid, or 4 µg/mL of metronidazole, followed by anaerobic incubation for 7 d. Bacterial test species presumptively positive for ß-lactamase production were identified by growth on EBBA primary isolation plates supplemented with amoxicillin alone and no growth on EBBA primary isolation plates containing both amoxicillin plus clavulanic acid. A subset of such isolates was subjected to nitrocefin-based chromogenic disk testing to confirm the presence of ß-lactamase activity. In vitro resistance to 4 µg/mL of metronidazole was noted when growth of test species occurred on metronidazole-supplemented EBBA culture plates. RESULTS: Two-hundred and ninety-four (52.1%) of the study subjects yielded ß-lactamase-producing subgingival bacterial test species, with Prevotella intermedia/nigrescens, Fusobacterium nucleatum and other Prevotella species most frequently identified as ß-lactamase-producing organisms. Of the ß-lactamase-producing bacterial test species strains recovered, 98.9% were susceptible in vitro to metronidazole at 4 µg/mL. CONCLUSION: The occurrence of ß-lactamase-positive subgingival bacterial species in more than half of the subjects with severe chronic periodontitis raises questions about the therapeutic potential of single-drug regimens with ß-lactam antibiotics in periodontal therapy. The in vitro effectiveness of metronidazole against nearly all recovered ß-lactamase-producing subgingival bacterial species further supports clinical periodontitis treatment strategies involving the combination of systemic amoxicillin plus metronidazole.

16S Ribosomal RNA Identification of Prevotella nigrescens from a Case of Cellulitis

No abstract available.

[Inhibition of extracts from 17 Chinese herbs on periodontal pathogenic microbes].

PURPOSE: To evaluate the efficiency of 17 Chinese herbs on periodontal pathogenic microbes. METHODS: 17 efficient substances from Chinese herbs were purchased from Chinese Drug Identification Bureau, including magnesium lithospermate B, magnolol, tetramethyl pyrazine, matrine, dycyrrhizin, gentiopicrin, aloperin, baicalin, oleanolic acid, ginkgo seed, total glucosides of paeony capsules, anisldehyde, archin, cablin patchouli, hydrochloric acid Berberine, forsythin, and kakonein. Antimicrobial sensitivity tests of broth microdilution methods on 96-microwell plate were carried out for identification of the antimicrobial activity of extracts against six species of microorganisms: Actinobacillus actinomycete mitans(Aa) Y4, Actinomycetes viscosus(Av) 19246, Porphyromonas gingivalis(Pg) 33277, Fusobacterium necrophorum(Fn) 25286, Actinomyces naeslundii(An) wvl 45 and Prevotella nigrescens(Pn). RESULTS: It was found that magnesium lithospermate B and magnolol showed the most efficient inhibition on microorganism of Pn and Fn, with the MIC being 0.053 and 0.313 mg/ml for Pn and Fn, respectively. Tetramethyl pyrazine, matrine, dycyrrhizin, gentiopicrin, aloperin, baicalin, and oleanolic acid had better inhibition than total glucosides of paeony capsules, anisldehyde, archin, cablin patchouli, hydrochloric acid berberine, forsythin, and kakonein. CONCLUSION: The Chinese herbs, magnesium lithospermate B and magnolol are efficient agents for inhibition against periodontal pathogenic microbes.

[Bacterial spectra and antibiotics in odontogenic infections. Renaissance of the penicillins?]. / Keimspektren und Antibiotika bei odontogenen Infektionen. Renaissance der Penicilline?

BACKGROUND: The role played by odontogenic infection in dental, oral, and maxillofacial surgery is not to be underestimated even at the present time. An extensive, standardized, prospective study was performed with the intention of verifying the bacterial spectrum of odontogenic infections to evaluate antibiotic sensitivity. MATERIAL AND METHODS: Bacterial spectra and resistograms of 65 patients with an odontogenic infection were analyzed in a prospective study under standardized conditions for specimen collection and transport. RESULTS: A total of 226 bacterial strains were analyzed. The ratio between anaerobes and aerobes was approximately 2:1. The most frequent aerobes were members of the genera Streptococcus (46 isolates), Staphylococcus (10 isolates), and Neisseria (9 isolates), respectively. The anaerobic gram-positive spectrum was dominated by members of the genera Eubacterium (19 isolates), Peptostreptococcus (16 isolates), and Actinomyces (12 isolates). The most frequently isolated gram-negative anaerobes were Prevotella (46 isolates), and Fusobacterium (21 isolates). The overall resistance to antibiotics was very low: only 7.3% of all bacteria were resistant to penicillin G/V, and 8.8% showed resistance to ampicillin. The resistance rates to other beta-lactam antibiotics were 4.4% to piperacillin and 0.6% to imipenem, respectively. Penicillin G presented the highest antimicrobial activity among aerobes: only 4.5% of anaerobic strains were resistant of penicillin G. The other resistance rates of anaerobic bacteria to antibiotics were as follows: ampicillin 24%, doxycycline 34%, erythromycin 18%, and clindamycin 9.3%. Penicillin G was also highly antimicrobially active to anaerobes. The resistance rates were: penicillin G 8.1%, ampicillin 2.6%, doxycycline 9.2%, erythromycin 10.2%, and clindamycin 1.4%, respectively.

Coptidis rhizoma inhibits growth and proteases of oral bacteria.

OBJECTIVE: The aim of this study was to investigate the antibacterial effect of Coptidis Rhizoma (CR), a traditional medicinal plant, on oral bacteria. MATERIALS AND METHODS: CR extract was prepared by boiling CR in water for 2 h. Alkaloids contained in CR extract were assayed by high performance liquid chromatography (HPLC). Antibacterial activity of CR extract was estimated from the lowest concentration that did not permit bacterial growth (minimum inhibitory concentration, MIC) and the concentrations that inhibited 50% of bacterial proteolytic activity (IC50). RESULTS: CR extract inhibited the growth of Actinomyces naeslundii, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens and Actinobacillus actinomycetemcomitans at MIC of 0.031-0.25 mg ml(-1), whereas it had less inhibitory effect (MIC: 0.5-2 mg ml(-1)) on the growth of Streptococcus and Lactobacillus. The major active component of CR extract was berberine (Ber), an alkaloid, and its inhibiting specificity to bacterial growth was similar to that of CR extract. CR extract and Ber were bacteriostatic at the MICs against most of the bacteria, and bacteriocidal at the concentrations higher than the MICs. Ber inhibited the activities of collagenase from P. gingivalis and A. actinomycetemcomitans. CONCLUSION: CR extract and Ber had an inhibitory effect on periodontopathogenic bacteria. These results suggest the possibility of their clinical application for the treatment of periodontal diseases.