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Crescimento, teor e composição do óleo essencial de melissa cultivada sob malhas fotoconversoras

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The activity of the first enzyme of the shikimate pathway, 3-deoxy-Darabino-heptulosonate 7-phosphate synthase, varies during the growth cycle of Solanum tuberosum L. cv superior cells in suspension culture. Maximum specific enzyme activity was observed midway through the linear phase of growth. When mid-log phase cells are exposed to glyphosate, the specific activity of the enzyme increases severalfold within 24 hours. The glyphosate-induced increase in enzyme activity is due to an increase in the amount of enzyme as determined by immunoblotting. Glyphosate (up to 2 millimolar) has no effect on the enzyme activity in vitro. Dehydroquinate synthase, the second enzyme of the shikimate pathway, is not induced by glyphosate.

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RESUMO A maioria das plantas são resistentes aos diferentes patógenos, e essa resistência pode estar relacionada à existência de compostos fungistáticos naturalmente produzidos. Com o presente trabalho, avaliouse a atividade fungitóxica de óleos essenciais de eucaliptos. Os óleos foram obtidos de folhas dos eucaliptos mediante arraste a vapor de água, utilizando o aparelho de Clevenger modificado. Nos ensaios biológicos, foram empregados os fitopatógenos Fusarium oxysporum, Botrytis cinerea e Bipolaris sorokiniana. O crescimento dos microorganismos na presença de diferentes concentrações de óleo (5, 50 e 500 mg/Kg), usando os meios de cultura BDA (Batata-Dextrose-Ágar) e PCA (Batata-CenouraÁgar), foi avaliado. Nas concentrações de 500 mg/Kg dos óleos, foram observadas inibições significativas no crescimento micelial das espécies fúngicas, após período de 7 dias. No entanto, o óleo essencial de Eucalyptus urophylla foi o que apresentou maior ação fungitóxica, que foi atribuída à presença do composto denominado globulol, ausente no E.camaldulensis e no E. citriodora. TERMOS PARA INDEXAÇÃO:Eucalyptus, óleo essencial, atividade fungitóxica. FUNGITOXIC ACTIVITY EVALUATION OF ESSENTIAL LEAF OILS OF Eucalyptus ON Fusarium oxysporum, Botrytis cinerea AND Bipolaris sorokinianaABSTRACT Most plants are resistant to different pathogens and this resistance may be related to the existence of naturally produced fungistatic components. The present work evaluated the fungitoxic activity of essential oils from three eucalyptus species. The essential oils were obtained from eucalyptus leaves by steam distillation using a modified Clevenger apparatus. The phytopatogens Fusarium oxysporum, Botrytis cinerea and Bipolaris sorokiniana were employed in the biological tests. The growth of fungi in the presence of different concentrations of oil (5, 50, and 500 mg/kg), using BDA (Potato-Dextrose-agar) and PCA (PotatoCarrot-agar) culture media were evaluated. Significant inhibition of the micelial growth of the fungal species was observed at the concentration of 500 mg/kg of oil after a period of seven days. The essential oil of Eucalyptus urophylla showed the greatest fungitoxic activity. This fact was attributed to the presence of the compound globulol, which was absent in the oils obtained from E. camaldulensis and E. citriodora.

A variação sazonal na composição química do óleo essencial em populações de Baccharis trimera natural e cultivada indicou a presença de três grupos de óleos em relação à origem e à fase de desenvolvimento das amostras. O primeiro incluiu amostras floridas, silvestres ou cultivadas, no período entre março-maio, contendo altas percentagens de globulol e espatulenol. No grupo II, com amostras silvestres coletadas entre junho-fevereiro, os constituintes majoritários foram o germacreno D e o (E)-cariofileno, enquanto que o grupo III incluiu amostras cultivadas entre junho-fevereiro e contendo um alto conteúdo de ledol. A análise por correlação canônica indicou que (E)-cariofileno, Mn, saturação por Al e precipitação foram fortemente correlacionados às amostras silvestres (grupo II), enquanto ledol e guaiol correlacionaram-se ao balanço químico do solo (P, K, S, Cu, Zn e saturação por bases) nas amostras cultivadas (grupo III). Ambos os óleos essenciais tem predominantemente hidrocarbonetos, embora em dois meses o conteúdo em sesquiterpenos oxigenados seja superior a 40% para ambas as amostras. As variações observadas podem estar relacionadas ao ambiente.The seasonal variations in the chemical composition of the essential oil of wild and cultivated Baccharis trimera populations indicated the presence of three clusters of oils regarding population and phenophase. The first included flowering, wild, and cultivated samples from a period of March-May, with high percentages of globulol and spathulenol. In cluster II, with wild samples collected from June-February, the major constituents were germacrene D and (E)-caryophyllene, while cluster III included cultivated samples from June-February containing a high content of ledol. The canonical correlation analysis revealed that (E)-caryophyllene, Mn, Al saturation, and precipitation were quite strongly related to wild samples (cluster II), whereas ledol and guaiol were related to chemical balance in soils (P, K, S, Cu, Zn, and base saturation) of cultivated samples (cluster III). Both essential oils have predominantly hydrocarbon compositions, although for a couple of months the oxygenated sesquiterpene content is over 40% for both samples. The observed chemovariation might be environmentally determined. Vol. 18, No. 5, 2007 popular uses in Brazil show that B. trimera is employed in the treatment of malaria, sore throat and tonsillitis, angines, anaemia, urinary inflammation and leprosy. [2][3][4] Liver-protective properties, gastrointestinal action, potential antidiabetic activity, and anti-arthritic effects have been validated, 5,6 and the anti-ophidian, relaxant, antimutagenic, antimicrobial, and antiprotozoal activities have also been reported. 7,8 Chemical studies revealed the presence of clerodanetype diterpenes, saponins and their glycosides, and several flavonoids in this species. 5,7 Carqueja oil, a commercial fragrance cited as a reminiscent of rosewood, 9 is stemdistilled from its aerial parts, with the unusual monoterpene alcohol carquejol and its acetyl ester ...

Yield and composition of essential oil of lemongrass in different drying and fragmentation conditionsIn this study the drying and fragmentation conditions of lemongrass leaves were determined, to increase the essential oil yield. Four replications of six treatments were studied with 2 drying methodologies (oven-drying at 40ºC and room temperature using moisture dryer) and 3 fragmentation sizes (powder obtained in mill, 1 cm and 20 cm fragments). The essential oil was extracted in Clevenger's modified apparatus during 2 hours. The higher essential oil yield and citral content was obtained with the leaves dried under room temperature using moisture dryer, with no significant differences in the fragmentation sizes.