Further Polycyclic Quinones of Micromonospora sp.

The crude acetone extract of a marine Micromonospora sp. strain associated with Eudistoma vannnamei was fractioned with hexane and ethyl acetate. The crude extract and both soluble fractions were assayed against several bacteria strains. The new polycyclic quinones 12-hydroxy-9-propyltetracene-6,1-dione (1), 5,12-dihydroxy-4-methoxy-9-propyltetracene-5,12-dione (2), and 4,6-dihydroxy-3-methoxycarbonyl- methyl-6a-(oxobutyl)-5,12-anthraquinone (3), along with the known 4,6-dihydroxy-3-methoxycarbonyl-methyl-6a-(oxo-3-methyl-butyl)-5,12-anthraquinone (4) and 4,6-dihydroxy-3-methoxycarbonyl-methyl-6a-(oxopentyl)-5,12-anthraquinone (5) were isolated from the hexane-soluble fraction, while from the active ethyl acetate fraction were isolated the known 4,6,11-trihydroxy-9-propyltetracene-5,12-dione (6), 4-methoxy-9-propyltetracene-6,11-dione (7), 7,8,9,10-tetrahydro-9-hydroxy-4-methoxy-9-propyltetracene-6,11-dione (8), and 10ß-carbomethoxy-7,8,9,10-tetrahydro-4,6,7α,9α,11-pentahydroxy-9-propyltetracene-5,12-dione (9). The structures of the new compounds were established by interpretation of HRMS and NMR techniques. A study of molecular docking was performed with the compounds from the active ethyl acetate fraction to correlate tentatively with the antimicrobial activity. Molecular docking, RMSD, RMSF, and MM-GBSA evaluations were performed to investigate the inhibitory activity of 6-8 against the protein PDB-codex 1MWT, being considered a promising target for studying drug development responsible for inhibiting replication of Staphylococcus aureus. Penicillin G was used as the standard inhibitory. Anthracyclinones 6-8 were the best hydrolase inhibitor with affinity energy -8.1 to -7.9 kcal/mol compared to penicillin G, which presented -6.9 kcal/mol. Both 8 and 7 present potent inhibitory effects against hydrolase through molecular dynamics simulation and exhibit favorable drug-like properties, promising new hydrolase blockers to fight bacterial infections from Staphylococcus aureus.

Antibacterial and antifungal action of CTAB-containing silica nanoparticles against human pathogens.

New antibiotic agents are urgently needed worldwide to combat the increasing tolerance and resistance of pathogenic fungi and bacteria to current antimicrobials. Here, we looked at the antibacterial and antifungal effects of minor quantities of cetyltrimethylammonium bromide (CTAB), ca. 93.8 mg g-1, on silica nanoparticles (MPSi-CTAB). Our results show that MPSi-CTAB exhibits antimicrobial activity against Methicillin-resistant Staphylococcus aureus strain (S. aureus ATCC 700698) with MIC and MBC of 0.625 mg mL-1 and 1.25 mg mL-1, respectively. Additionally, for Staphylococcus epidermidis ATCC 35984, MPSi-CTAB reduces MIC and MBC by 99.99% of viable cells on the biofilm. Furthermore, when combined with ampicillin or tetracycline, MPSi-CTAB exhibits reduced MIC values by 32- and 16-folds, respectively. MPSi-CTAB also exhibited in vitro antifungal activity against reference strains of Candida, with MIC values ranging from 0.0625 to 0.5 mg mL-1. This nanomaterial has low cytotoxicity in human fibroblasts, where over 80% of cells remained viable at 0.31 mg mL-1 of MPSi-CTAB. Finally, we developed a gel formulation of MPSi-CTAB, which inhibited in vitro the growth of Staphylococcus and Candida strains. Overall, these results support the efficacy of MPSi-CTAB with potential application in the treatment and/or prevention of infections caused by methicillin-resistant Staphylococcus and/or Candida species.

Chemical Composition Determination and Evaluation of the Antimicrobial Activity of Essential Oil from Croton blanchetianus (Euphorbiaceae) against Clinically Relevant Bacteria.

In this study, the chemical composition of the essential oil (EO) extracted from Croton blanchetianus Baill leaves was identified, and antimicrobial and antibiofilm activities against Staphylococcus aureus, Staphylococcus epidermidis, and Escherichia coli strains were determined. Moreover, the effects of EO in combination with ampicillin and tetracycline were investigated. Thirty-four components, mainly mono-and sesquiterpenes that represented 94.05 % of the chemical composition, were identified in the EO. The EO showed bacteriostatic and bactericidal activities against all strains tested. Furthermore, the EO showed a synergistic effect with ampicillin and tetracycline. EO significantly inhibited biofilm formation and reduced the number of viable cells in biofilms. The EO may be a promising natural product for preventing bacterial biofilm infections.

Fruticulosin: A novel type 2 ribosome-inactivating protein from Abrus fruticulosus seeds that exhibits toxic and antileishmanial activity.

Plant ribosome-inactivating proteins (RIPs) are a family of toxins that inhibit protein synthesis. In this study, we have isolated a novel type 2 ribosome-inactivating protein (RIP) present in seeds of the Abrus fruticulosus, named of fruticulosin. Fruticulosin, shows characteristics common to other type 2 RIPs, as specificity by galactosides (d-galactose, N-acetyl-d-galactosamine, and d-lactose), mass of approximately 60 kDa and presence of the of disulfide bonds. The N-terminal amino acid sequence (26 residues) of A-chain fruticulosin, determined by Edman degradation, revealed high similarity of the A-chain with those of other type 2 RIPs. The secondary structure of fruticulosin was analysed by circular dichroism, which showed that fruticulosin contains α-helices (22.3%), ß-sheets (43.5%), and random coils and corners (34.2%). Furthermore, fruticulosin showed high toxicity in Artemia sp. (3.12 µg/mL), inhibited in vitro protein synthesis by a cell-free system and showed RNA N-glycosidase activity. Fruticulosin presented biological activities such as agglutination and antileishmanial activity on promastigote forms of Leishmania major.

Uso do cariogram® na avaliação do risco de cárie em crianças em um municípiobrasileiro: estudo piloto / Caries risk assessment in children using Cariogram® in a Brazilian city: pilot study / El uso del Cariogram® en la evaluación del riesgo de caries niños de un municipio brasileño: estudio piloto

Analisar o risco de cárie dentária em crianças de 12 anos de idade por meio da utilização do Cariogram®. Métodos: Estudo descritivo realizado com 31 crianças de 12 anos de idade de uma escola pública de ensino fundamental em um município do Nordeste brasileiro, no ano de 2009. Coletaram-se dados referentes à experiência de cárie e doenças sistêmicas relacionadas; presença de açúcar na dieta e frequência de ingestão; quantidade de placa e contagem de estreptococos do grupo mutans; uso de produtos fluoretados, fluxo salivar e capacidade tampão. Todos estes dados foram inseridos no Cariogram® para que se pudesse obter um perfil de risco de cárie individual e a capacidade de evitar novas lesões. Resultados: Verificou-se que 78% (n=24) das crianças apresentaram riscos individuais de cárie nos níveis intermediário e alto; 45% (n=14) dos participantes apresentaram menos de 50% de chance de evitar novas lesões de cáries. Ainda, que 6,45% (n= 2) das crianças apresentavam possibilidade de evitar novas lesões de cárie menor que 75%, ou seja, configuravam em alto risco de desenvolvimento de cárie; e 12,90% (n= 4) apresentavam uma possibilidade maior que 75%, sendo caracterizado como baixo risco de evitar estas lesões. Houve associações positivas (p<0,05) entre presença de açúcar na dieta e fluxo salivar, em que indivíduos com dieta cariogênica apresentavam fluxo salivar diminuído. Conclusão: Verificou-se um padrão de risco de cárie nos níveis intermediário e alto, com susceptibilidade acima de 10% e possibilidade de evitar novas lesões de cárie inferior a 50%...

To analyze the risk of dental caries in 12-year-old children through the use of Cariogram®. Methods: Descriptive study conducted with 31 children, aged 12 years, in apublic elementary school in a city of the Brazilian Northeast, in 2009. Data was collected regarding caries experience and related systemic disease; presence of sugar in the diet and intake frequency; Streptococcus mutans biofilm growth and bacterial counts; use of fluoride products, salivary flow and buffering capacity. All this data was inserted into Cariogram®, in order to obtain a profile of individual caries risk and the ability to prevent new cariouslesions. Results: It was found that 78% (n=24) of the children had individual risk of dental caries in the intermediate and high levels; 45% (n=14) of the participants had less than a 50% chance of avoiding new cavities. Furthermore, 6.45% (n=2) of the children had less than 75% possibility of avoiding new carious lesions, i.e., they featured high risk of caries development, and 12.90% (n=4) had a possibility of more than 75%, being characterized as low risk of developing such injuries. There were positive associations (p<0.05) between the presence of sugar in the diet and salivary flow, in which subjects with cariogenic diet had decreased salivary flow. Conclusion: A caries risk pattern was found in the intermediate and high levels, with susceptibility above 10% and possibility of avoiding new caries lesions under 50%...

Objetivo: Analizar el riesgo de caries dentaria en niños de 12 años de edad con la utilización del Cariogram®. Métodos: Estudio descriptivo realizado con 31 niños de 12 años de edad en uma escuela pública de enseñanza fundamental de un municipio Del Nordeste brasileño en 2009. Se recogió datos sobre la experiência de caries y enfermedades sistémicas relacionadas; presencia de azúcar en la dieta y frecuencia de ingestión; cantidad de placa y recuento de estreptococus del grupo mutans; el uso de productos fluorados, flujo salival y capacidad de tapón. Todos los datos fueron inseridos en el Cariogram® para obtener un perfil de riesgo de caries individual y la capacidad de evitar nuevas lesiones. Resultados: Se verificó que el 78% (n=24) de los niños presentaron riesgos individuales de caries en los niveles intermediario y alto; el 45% (n=14) de los participantes presentaron menos del 50% de oportunidad de evitar nuevas lesiones de caries. Además, el 6,45% (n= 2) de los niños presentaron la posibilidad de evitar nuevas lesiones de caries abajo del 75%, es decir, presentaron riesgo elevado de desarrollo de caries; y el 12,90% (n= 4) presentaron una mayor posibilidad que el 75% caracterizando el bajo riesgo en evitar estas lesiones. Hubieron asociaciones positivas (p<0,05) de la presencia del azúcar en la dieta y el flujo salival en la cual los individuos con dieta cariogénica presentaron flujo salival disminuido. Conclusión: Se verificó un patrón de riesgo de caries en los niveles intermediario y alto con susceptibilidad mayor que el 10% y posibilidad de evitar nuevas lesiones de caries menor que el 50%...