Resumo Objetivo O objetivo deste estudo foi obter extratos por diferentes métodos de extração de Casearia sylvestris, incluindo a obtenção de óleo essencial, a fim de comparar suas atividades antimicrobianas em relação aos enxaguatórios bucais convencionais com clorexidina contra bactérias orais. Material e método Para esta avaliação, extratos das folhas foram obtidos por diferentes métodos de extração (infusão, decocção, maceração e percolação) utilizando diferentes sistemas de solventes: 100% de água, 100%, de etanol, metanol 100%, água: etanol 3: 7; água: etanol 7: 3; água: metanol 7: 3 e água: metanol 3: 7. O óleo essencial, que corresponde a uma fração volátil, foi obtido por hidrodestilação usando o aparelho de Clevenger modificado. O método de microdiluição em caldo foi usado para determinar os valores de concentração inibitória mínima (MIC) e a concentração bactericida mínima (MBC) para os seguintes microrganismos: Streptococcus mutans ATCC 25175, ATCC 49456 S. mitis, S. sanguinis ATCC 10556, S. salivarius ATCC 25975, Lactobacillus casei ATCC 11578 e Enterococcus faecalis ATCC4082. Gluconato de clorexidina foi usada como um controle positivo. Resultado Todos os extratos avaliados no protocolo utilizado apresentaram valores de MIC superior a 400 ug/mL e alguns mostraram atividade bactericida. A atividade antimicrobiana do óleo essencial foi maior do que a atividade dos extratos, e a melhor concentração inibitória mínima e valores de concentração bactericida mínima foram obtidos contra L. casei (MIC de 0,023 ug/mL e MBC de 0,046 ug/mL) e S. mutans (MIC de 25 ug/mL e MBC de 50 ug /mL), respectivamente. Conclusão O óleo essencial de Casearia sylvestris tem atividade antimicrobiana significativa contra microrganismos orais.

Abstract Aim The aim of this study was to obtain Casearia sylvestris leave extracts by different extractive methods, including the obtention of essential oil, in order to compare their antimicrobial activities to conventional mouthwash chlorhexidine against oral bacteria. Material and method For this evaluation, extracts from the leaves were obtained by different methods of extraction (infusion, decoction, maceration and percolation) using different solvent systems: water 100%, ethanol 100%, methanol 100%, water: ethanol 3:7; water: ethanol 7:3; water: methanol 7:3 and water: methanol 3:7. The essential oil, which corresponds to a volatile fraction, was obtained by hydrodistillation using Clevenger modified apparatus. The microdilution broth method was used to determine the values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for the following microorganisms: Streptococcus mutans ATCC 25175, S. mitis ATCC 49456, S. sanguinis ATCC 10556, S. salivarius ATCC 25975, Lactobacillus casei ATCC 11578 and Enterococcus faecalis ATCC4082. Chlorhexidine gluconate was used as a positive control. Result All extracts evaluated in the used protocol displayed MIC values higher than 400 µg/mL and few showed bactericidal activity. The antimicrobial activity of essential oil was higher than the activity of the extracts, and the best minimum inhibitory concentration and minimum bactericidal concentration values were obtained against L. casei (MIC of 0.023 µg/mL and MBC of 0.046 µg/mL) and S. mutans (MIC of 25 µg/mL and MBC of 50 µg/mL), respectively. Conclusion The essential oil of Casearia sylvestris has significant antimicrobial activity against oral microorganisms.

The international organizations CLSI and EUCAST developed reference methodologies for activity evaluation antifungal. The aim of this work was to compare the recommended methodologies by the CLSI and EUCAST in the antifungal activity evaluation of crude extracts of Azadirachta indica and green propolis. The results showed that the MIC values determined by the EUCAST methodology were smaller than that determined by the CLSI. Nevertheless, both methodologies were satisfactory to detect and evaluate antifungal activity of the crude extracts and isolated compounds. The EUCAST methodology showed advantage by making possible to obtain results in less time.

In this work, the effectiveness of four screening techniques (three techniques of the diffusion method and one microdilution broth method) were compared. Evaluated were the ethanolic and dichloromethanic extracts of Miconia rubiginosa (Melastomataceae) against six standard bacteria (ATCC). The results showed statistical disagreement among the three diffusion techniques. Among the diffusion techniques, the well technique displayed the best result. However the microdilution broth method demonstrated to be the most adequate method to evaluate the antibacterial activity of plant crude extracts and pure compounds when compared to the other methodologies.

A atividade antimicrobiana do extrato das folhas de Syzygium cumini (Myrtaceae), conhecido como "jambolão", foi avaliada. O extrato hidroalcoólico mostrou atividade contra Candida krusei (halo de inibição de 14.7 ± 0.3 mm e CIM = 70 µg/mL) e cepas multiresistentes de Pseudomonas aeruginosa, Klebsiella pneumoniae e Staphylococcus aureus.

The antimicrobial activity of Syzygium cumini leaves extract, known as "jambolão", was evaluated. The crude hydroalcoholic extract was active against Candida krusei (inhibition zone of 14.7 ± 0.3 mm and MIC = 70 µg/mL), and against multi-resistant strains of Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus.

Em estudos desenvolvidos para encontrar produtos naturais biologicamente ativos provenientes de fungos, uma cepa de Aspergillus fumigatus foi avaliada para a produção de atividade antimicrobiana. Quatro parâmetros, consistindo de meio de cultura, pH, temperatura e tempo de fermentação, foram investigados. Os extratos obtidos das culturas do fungo apresentaram perfis cromatográficos diferentes e produziram, ao menos, uma zona de inibição quando avaliados por bioautografia. Zonas de inibição sobrepostas na faixa de Rf 0.09 a 0.65, contra Kocuria rhizophila, foram detectadas na bioautografia do extrato clorofórmico obtido da cultura desenvolvida no meio de Jackson, pH inicial 6,0 e incubação a 40ºC por 144 horas. Entretanto, os extratos obtidos por desenvolver a cultura do fungo no meio de Vogel forneceram o menor número de compostos ativos. Os perfis cromatográficos obtidos dos extratos das culturas do fungo por cromatografia líquida de alta eficiência com detector de arranjo de diodos foram distintos, permitindo inferir que a produção de metabólitos secundários por Aspergillus fumigatus pode ser afetada pela modificação dos parâmetros investigados. Deve ser ressaltado que uma notável diferença nos perfis cromatográficos obtidos por CLAE foi observada por utilizar diferentes meios de cultura.

During the course of screening for biologically leading active natural products from fungi, a strain of Aspergillus fumigatus was assessed for antimicrobial activity production. Four parameters consisting of medium culture, pH, temperature and time of fermentation were investigated. The extracts from the fungus cultures displayed different TLC profiles and produced, at least, one inhibition zone in the bioautography assays. Overlapping inhibition zones in the range of Rf 0.09 to 0.65 against Kocuria rhizophila were detected in the bioautography assay of the chloroform extract obtained from Jackson's medium culture, initial pH of 6.0 and incubation at 40ºC for 144 hours. However, the obtained extracts by developing the fungus culture in Vogel's medium furnished the smallest number of active compounds. The obtained chromatographic profiles of the extracts from the fungus cultures by high performance liquid chromatography with photodiode array detector were distinctive, allowing to infer that A. fumigatus secondary metabolites production could be affected by modifying any of the undertaken parameters. It should be pointed out that a remarkable difference among HPLC profiles was observed by using different media culture.