Ana Paula Soares Pinto Salgado

Caracterização química e efeito inibitório de óleos essenciais sobre o crescimento de Staphylococcus aureus e Escherichia coli

Objetivou-se avaliar o efeito inibitorio dos oleos essenciais de Cymbopogon citratus (capim-limao), Origanum vulgare (oregano) e Syzygium aromaticum (cravo-da-india); os experimentos foram realizados com as bacterias Staphylococcus aureus e Escherichia coli, importantes patogenos causadores de contaminacoes em queijos e outros alimentos. Para quantificacao e identificacao dos constituintes quimicos dos oleos, utilizou-se um cromatografo gasoso acoplado a um espectrometro de massa. Os resultados dos testes in vitro, os oleos essenciais de C. citratus, O. vulgare e S. aromaticum promoveram efeito inibitorio sobre as bacterias S. aureus e E. coli, porem o S. aromaticum apresentou melhor formacao de halo de inibicao nas menores concentracoes. Para o efeito sinergistico dos oleos sobre as bacterias nao foram observadas diferencas quando comparados com o efeito individual dos mesmos. Foi possivel verificar que os oleos possuem efeito inibitorio sobre os microrganismos estudados, sendo, portanto uma alternativa no controle microbiologico de alimentos.

A convenient method for the determination of moisture in aromatic plants

A method is proposed for the determination of the moisture content of aromatic plants. This method is based on the co-distillation of the starting material in a modified Clevenger apparatus with four organic solvents (toluene, cyclohexane, dichloromethane and carbon tetrachloride). The results were compared with those obtained by oven drying at 105 oC and steam distillation of the essential oil. The efficiencies of the methods were shown to be equivalent. The solvent distillation method was more practical, especially with respect to operating time (2 h).

Avaliação da atividade fungitóxica de óleos essenciais de folhas de Eucalyptus sobre Fusarium oxysporum, Botrytis cinerea e Bipolaris sorokiniana

A maioria das plantas sao resistentes aos diferentes patogenos, e essa resistencia pode estar relacionada a existencia de compostos fungistaticos naturalmente produzidos. Com o presente trabalho, avaliou-se a atividade fungitoxica de oleos essenciais de eucaliptos. Os oleos foram obtidos de folhas dos eucaliptos mediante arraste a vapor de agua, utilizando o aparelho de Clevenger modificado. Nos ensaios biologicos, foram empregados os fitopatogenos Fusarium oxysporum, Botrytis cinerea e Bipolaris sorokiniana. O crescimento dos microorganismos na presenca de diferentes concentracoes de oleo (5, 50 e 500 mg/Kg), usando os meios de cultura BDA (Batata-Dextrose-Agar) e PCA (Batata-Cenoura-Agar), foi avaliado. Nas concentracoes de 500 mg/Kg dos oleos, foram observadas inibicoes significativas no crescimento micelial das especies fungicas, apos periodo de 7 dias. No entanto, o oleo essencial de Eucalyptus urophylla foi o que apresentou maior acao fungitoxica, que foi atribuida a presenca do composto denominado globulol, ausente no E.camaldulensis e no E. citriodora.

Efeito do óleo essencial de pimenta longa (Piper hispidinervum C. DC) e do emulsificante Tween® 80 sobre o crescimento micelial de Alternaria alternata (Fungi: Hyphomycetes)

The object of this work was to evaluate the effectof essential oils from Long-pepper leaves Piper hispidinervum on the mycelial growth of Alternaria alternata and to analyze the influence of emulsifier Tween® 80 concentration in the control of this phytopathogen. The essential oil was obtained by steam stream distillation, using a modified Clevenger apparatus, and the chemical composition was analyzed by gas chromatography coupled to mass spectroscopy GC-MS and GC. For biological tests, the bioanalytical in vitro method was used, observing the growth or inhibition of such phytopathogen in BDA culture media, in the presence of different essential oil concentrations (0, 100, 250, 500, e 1000 mgL -1) under different Tween® 80 concentrations. Factorial scheme with four repetitions, in entirely randomized outline was adopted. The essential oil of Long-pepper inhibited the micellial growth of the A. alternata fungus at all of the concentrations tested. A 100% inhibition at the 1000 mgL -1 concentration was observed, and the percentage of emulsifier (Tween® 80) influenced the fungitoxic activity at the 250 mgL-1 and 500 mgL -1 concentrations of the essential oil.

Potencial fungitóxico do óleo essencial de Piper hispidinervum (pimenta longa) sobre os fungos fitopatogênicos Bipolaris sorokiniana, Fusarium oxysporum e Colletotrichum gloeosporioides

The objective of this study was to evaluate the in vitro antifungal activity of the essential oil of the leaves of Piper hispidinervum against Bipolaris sorokiniana, Fusarium oxysporum and Colletotrichum gloeosporioides. For the biological tests, using the bioanalitic test in vitro the concentrations of 100, 200, 500, 1000, 1500 and 2000 µg.mL-1 the essential oil. This were incorporated into PDA (potato dextrose agar) medium in order to evaluate fungal mycelial growth or inhibition. The statistic design used was completely randomized, with four replicates. In the concentration of 200 µg.mL-1, observed inhibited complete the phytopathogens Bipolaris sorokiniana while the Fusarium oxysporum and Colletotrichum gloeosporioides this is occurred in the concentration of 1000 µg.mL-1.

Influência da temperatura de secagem sobre o rendimento e a composição química do óleo essencial de Tanaecium nocturnum (barb. Rodr.) bur. & K. Shum

The yields and chemical compositions of the essential oils obtained by steam distillation of the fresh and dried (30 and 40 oC) leaves, stems and roots of Tanaecium nocturnum are reported. The identification and quantification of the volatile constituents were accomplished by GC/MS and GC/FID, respectively. The essential oils obtained from the various parts of the plant were constituted mainly of benzaldehyde. Large losses and variations in the quantities of the components during the drying process were observed. The presence of mandelonitrile in higher concentration in the stem and roots indicates that this species produces cyanogenic glycosides.