RESUMO:Os dados obtidos na literatura sobre a atividade antimicrobiana dos óleos essenciais são tratados do ponto de vista experimental, considerando-se uma possível aplicação clínica dos óleos. O presente estudo teve como objetivo analisar os fatores que infl uenciam na atividade antimicrobiana de óleos essenciais, in vitro, com base nos resultados descritos na literatura. Foi verifi cado que os testes e avaliações da atividade antimicrobiana dos óleos essenciais podem ser difi cultados pela volatilidade do óleo, sua insolubilidade em água e sua complexidade química. Tais difi culdades tornam os resultados disponíveis na literatura, difíceis de comparar. Por outro lado, os métodos usados diferem largamente e fatores importantes que infl uenciam os resultados são freqüentemente negligenciados. Assim, após breve levantamento, concluiu-se que alguns fatores devem ser levados em consideração, tais como: a técnica usada, o meio de cultura, densidade do inóculo, o óleo essencial e o emulsifi cador utilizado. Portanto, para a realização de testes que visam verifi car a atividade antimicrobiana de óleos essenciais, é necessário defi nir e adotar uma metodologia adequada e bem padronizada.Unitermos: Óleo essencial, atividade antimicrobiana, métodos.ABSTRACT: "Antimicrobial activity of the essentials oils: a multifactor approach of the methods". The given data of the literature on the antimicrobial activity of the essential oils are treated from the experimental point of view, and they consider a possible clinical application of the oils. The purpose of this study is to analyze the factors that can infl uence on antimicrobial activity of essential oils, in vitro, based on preview data from literature. We noticed that the tests and evaluations of the antimicrobial activity of the essential oils can be hindered by the volatility of the oil, its insolubility in water and its chemistry complexity. These details make the results obtained on literature diffi cult to compare. The used methods differ broadly and important factors that infl uence the results are frequently neglectful. After a bibliographical rising, we concluded that a large attention should be given to some factors when we work with essential oils: the used technique, the growth medium, the inoculums density, the tested essential oil and the used emulsifying. It's necessary to defi ne and follow a right and standard methodology to make antimicrobial activity testes of essential oils.Keywords: Essential oil, antimicrobial activity, methods. INTRODUÇÃOÓleos e extratos de plantas há muito tempo têm servido de base para diversas aplicações na medicina popular, entre elas, a produção de anti-sépticos tópicos. Tal realidade serviu de base para diversas investigações científi cas, com vistas na confi rmação da atividade antimicrobiana dos óleos essenciais Arruda et al., 2006;Nunes et al 2006;Benkeblia, 2004;Rehder et al., 2004;Claffey, 2003;Seymour, 2003;Arweiler et al., 2000;Fine et al., 2000;Pan et al., 2000).Para tanto, tem se desenvolvido métodos de investigação in...

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The rupture of the Fundão mine dam in Mariana municipality, Minas Gerais State, Brazil, spilled the tailings across the Doce River basin. These tailings, composed of residues discarded from the beneficiation of iron ore, are rich in SiO 2 and Al 2 O 3 , as well as some ether amine compounds and NaOH. The aim of this study was to assess the distribution of these sediments, as well as their effect on the riparian zones reached, as compared with preserved sites. Sediment deposition in the river resulted in a morphological change from a meandering profile to a braided aspect. The nutrient and mineral content (P, K, Ca, Mg, Cu, Fe, Mn, Zn, and NO 3 − ) and soil organic matter of the sediments were depleted, whereas NH 4 + , Na, and pH increased. A random presence of ether amines in the sediments was confirmed by quantitative and chromatographic analyses, with concentrations ranging from 0 to 57.8 mg kg −1 ; Na reached values as high as 150 mg kg −1 . The impact of the dam tailings on biota was assessed by estimating total microbial biomass (phospholipid fatty acids), which were depleted in sediments relative to soils from preserved sites. Overall plant mortality, as well as a low resilience capacity, were also observed. Ether amines and Na present in the sediments had a strong toxic effect in the environment. Identification of these substances as the main impact factors will help guide future remediation efforts.

According to our results, H. pectinata essential oil can be considered a promising alternative to chlorhexidine for the control of oral bacteria-related diseases and hygiene.