Cymbopogon citratus essential oil: effect on polymicrobial caries-related biofilm with low cytotoxicity

Abstract The objective of this study was to evaluate the effects of Cymbopogon citratus essential oil and its main compound (citral) against primary dental colonizers and caries-related species. Chemical characterization of the essential oil was performed by gas chromatography/mass spectroscopy (GC/MS), and the main compound was determined. Antimicrobial activity was tested against Actinomyces naeslundii, Lactobacillus acidophilus, S. gordonii, S. mitis, S. mutans, S. sanguinis and S. sobrinus. Minimum inhibitory and bactericide concentrations were determined by broth microdilution assay for streptococci and lactobacilli reference, and for clinical strains. The effect of the essential oil on bacterial adhesion and biofilm formation/disruption was investigated. Negative (without treatment) and positive controls (chlorhexidine) were used. The effect of citral on preformed biofilm was also tested using the same methodology. Monospecies and microcosm biofilms were tested. ANOVA or Kruskal-Wallis tests were used (α=0.05). Cytotoxicity of the essential oil to human keratinocytes was performed by MTT assay. GC/MS demonstrated one major component (citral). The essential oil showed an inhibitory effect on all tested bacterial species, including S. mutans and L. acidophilus. Essential oil of C. citratus (10X MIC) reduced the number of viable cells of lactobacilli and streptococci biofilms (p < 0.05). The essential oil inhibited adhesion of caries-related polymicrobial biofilm to dental enamel (p < 0.01). Citral significantly reduced the number of viable cells of streptococci biofilm (p < 0.001). The essential oil showed low cytotoxicity to human keratinocytes. Based on these findings, this study can contribute to the development of new formulations for products like mouthwash, against dental biofilms.

Experimental oral chronic infection induced by actinomyces israelii and propionibacterium acnes

The purpose of this study was to evaluate an experimental animal model of oral chronic infection induced by Actinomyces israelii and propionibacterium acnes in mice. Swiss/NIH mice (n=100), 21 days of age, male and female were divided into two groups of 45 animals. A. israelii (n=45) and P. acnes (n=45) were inoculated in the anterior mandibular paraperiosteal periodontal tissue associated with sodium alginate gel particles. The animals were evaluated clinically and microscopically at 1,3,7,15,21,30 and 45 days after inoculation. Actinomycotic and propioni lesions were induced in all animals. In control mice (n=10), no lesions were noted; however, differences in the clinical and histopathological evoluations of actinomycosis and propioni lesions were observed and are discussed in this study. Microorganisms entrapped in alginate gel provided a prolonged bacterial irritation, and chronic histopathologic features similar to those seen in human actinomycosis could be detected.

Infecção oral crônica experimental induzida por actinomyces israelii e propionibacterium acnes / Experimental oral chronic infection induced by actinomyces israelii and propionibacterium acnes

The purpose of this study was to evaluate an experimental animal model of oral chronic infection induced by Actinomyces israelii and propionibacterium acnes in mice. Swiss/NIH mice (n=100), 21 days of age, male and female were divided into two groups of 45 animals. A. israelii (n=45)and P. acnes (n=45) were inoculated in the anterior mandibular paraperiosteal periodontal tissue associated with sodium alginate gel particles. The animals were evaluated clinically and microscopically at 1,3,7,15,21,30 and 45 days after inoculation. Actinomycotic and propioni lesions were induced in all animals. In control mice (n=10), no lesions were noted; however, differences in the clinical and histopathological evoluations of actinomycosis and propioni lesions were observed and are discussed in this study. Microorganisms entrapped in alginate gel provided a prolonged bacterial irritation, and chronic histopathologic features similar to those seen in human actinomycosis could be detected.

Germicide effect of several glass ionomer cements

Una de las características más importantes de los cementos de ionómero vítreo es la posibilidad de liberación de fluoruros. Este estudio fue llevado a cabo para tratar de establecer las relaciones entre esta cualidad y el efecto que ejercía sobre el desarrollo de los microorganismos que se encuentran en las lesiones cariosas. Cajas de petri que contenían agar BHI se inocularon con cepas de Actinomyces naeslundii, Actinomyces israelii y Actinomyces odontolyticus. Se realizaron cavidades en el agar que se llenaron con mezclas de diversos ionómeros vítreos. Algunos de ellos eran de resina polimerizable. Se utilizó cemento de fosfato de zinc y cemento de óxido de zinc eugenol como testigos. Después de 7 días de incubación a 37 grados C en condiciones de anaerobiosis, se midieron los halos de inhibición alrededor de las muestras, en una forma silimar a la que se hace para antibiogramas. El análisis estadístico de los resultados demostró que no había diferencias significativas entre las cepas de Actinomyces, pero era significativa entre los cementos. Aunque no se pueden extraer conclusiones definitivas, es válido tener en consideración el efecto de los cementos de ionómero vítreo sobre los Actinomyces. Se continuarán los estudios para clarificar la significación clínica de este hallazgo

Studies on the lceratinolytic enzymes of thermophilic Actinomycetes II-Partial purification and characterization of thermostable keratinase enzyme from Thermoactinomyces vulgaris C52

The thermostable keratinase enzyme, produced by Thermoacetinomyces vulgaris CS2 in liquid modified. Kosmatchev medium under the optimum condition, was purified 224-fold with an Overall yield of 36.08% of the original activity and specific activity 748.67 units mg [-1] protein by ammonium sulphate precipitation and ion exchange chromatography [DEAF-Cellulose]. Maximal activity of the enzyme was obtained at 55-60 and pH 8.4-85. It was stable at 45-55'in the pH 8.4-8.5. Also the enzyme was slightly activated by CaC12 MgSO4, FeSO4 and CuSO4, but strongly inhibited by KFeCN, KCN, iodine and iodoacedic acid. The partially purified enzyme actively hydrolyzed all keratinaceous waste materials used

Median rhomboid glossitis: secondary to colonisation of the tongue by Actinomyces (a case report).

Median rhomboid glossitis is an inflammatory lesion of the tongue, now believed to be secondary to candidiasis. We document a case of median rhomboid glossitis with heavy colonisation by Actinomyces in a 60-year-old male. We propose that Actinomyces, like Candida, induces pseudoepitheliomatous hyperplasia of the mucosa of the tongue and florid inflammatory hyperplasia of the underlying connective tissue, resulting in the characteristic elevated lesion. Actinomyces has not earlier been implicated as a cause of median rhomboid glossitis.