Composition, anti-quorum sensing and antimicrobial activity of essential oils from Lippia alba

Many Gram-negative pathogens have the ability to produce N-acylhomoserine lactones (AHLs) as signal molecules for quorum sensing (QS). This cell-cell communication system allows them to coordinate gene expression and regulate virulence. Strategies to inhibit QS are promising for the control of infectious diseases or antibiotic resistant bacterial pathogens. The aim of the present study was to evaluate the anti-quorum sensing (anti-QS) and antibacterial potential of five essential oils isolated from Lippia alba on the Tn-5 mutant of Chromobacterium violaceum CV026, and on the growth of the gram-positive bacteria S. aureus ATCC 25923. The anti-QS activity was detected through the inhibition of the QS-controlled violacein pigment production by the sensor bacteria. Results showed that two essential oils from L. alba, one containing the greatest geranial:neral and the other the highest limonene:carvone concentrations, were the most effective QS inhibitors. Both oils also had small effects on cell growth. Moreover, the geranial/neral chemotype oil also produced the maximum zone of growth inhibition against S. aureus ATCC 25923. These data suggest essential oils from L. alba have promising properties as QS modulators, and present antibacterial activity on S. aureus.

Chemical characterization of Lippia alba essential oil: an alternative to control green molds

The essential oil of Lippia alba is reported as an antifungal against human pathogenic microorganisms but few articles report its use as an alternative to synthetic fungicides on green mould control. The objective of this study was to determine chemical characteristics of L. alba essential oil and its antifungal activity against green molds as an alternative to synthetic fungicides. Essential oil was extracted by Clevenger hydrodistillation, characterized by GC-MS analysis, and the structure of the main compounds confirmed by ¹H and 13C-NMR spectroscopy. Microdilution assays evaluated the essential oil minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC). Commercial fungicides Ketoconazole and Bifonazole were used as control. Essential oil yield is of 0.15 percent and the major components are neral (33.32 percent) and geranial (50.94 percent). The L. alba essential oil has MIC of 0.300-1.250 mg/mL and MFC of 0.600-1.250 mg/mL. Ketoconazole and Bifonazole show MIC ranging from 0.025-0.500 to 0.100-0.200 mg/mL, and MFC ranging from 0.250-0.100 to 0.200-0.250 mg/mL, respectively. L. alba essential oil is classified as citral type and the results indicate that it is a potential alternative to synthetic fungicides.

Teor e composição de óleo essencial de rizomas de gengibre (Zingiber officinale Roscoe) após diferentes períodos de secagem / Essential oil yield and composition of ginger (Zingiber officinale Roscoe) rhizomes after different drying periods

A produção de gengibre no Paraná concentra-se no município de Morretes, ocupando uma área de plantio de aproximadamente 300 ha. O objetivo deste trabalho foi avaliar o teor e a composição do óleo essencial de rizomas de gengibre produzidos em Morretes e submetidos a diferentes períodos de secagem em temperatura ambiente. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 5 x 5, com quatro repetições (quatro plantas por repetição), avaliando cinco procedências e cinco períodos de secagem a temperatura ambiente (0, 15, 30, 45 e 60 dias). As extrações de óleo essencial foram realizadas por hidrodestilação em aparelho graduado Clevenger durante três horas e a análise dos constituintes foi realizada por meio de cromatografia em fase gasosa acoplada à espectrometria de massas. A secagem de rizomas de gengibre em temperatura ambiente por até 60 dias resultou na diminuição de teores de óleo essencial na maioria das procedências. Os constituintes geranial e o neral apresentaram maior concentração em todas as procedências e tiveram teores superiores com o aumento nos períodos de secagem. Os teores de geraniol e acetato de geranila foram inferiores após a secagem em todas as procedências, assim como eucaliptol, canfeno, zingibereno e β-bisaboleno na maioria das procedências.

Ginger production in Paraná State, Brazil, has predominated in Morretes Municipality, with around 300 ha cultivated area. The aim of this work was to evaluate the essential oil yield and composition of ginger rhizomes produced in Morretes and subjected to different drying periods at room temperature. Experimental design was completely randomized, in a 5x5 factorial arrangement, with four replicates (four plants each), five origins and five drying periods at room temperature (0, 15, 30, 45 and 60 days). The essential oil was extracted by hydrodistillation in a Clevenger-type device for 3h and the constituents were analyzed by gas chromatography-mass spectrometry (GC/MS). The drying of ginger rhizomes at room temperature for up to 60 days decreased the essential oil yield in most origins. Geranial and neral levels were higher in all origins and as drying periods were longer. Geraniol and geranyl acetate levels decreased after drying in all origins, as well as eucalyptol, camphene, zingiberene and β-bisabolene in most origins.

Emotional Intelligence, General Self-efficacy and Coping St yle of Delinquent Teenagers / 中国心理卫生杂志

Objective:To explore the characters of emotional intellige nc e and its relationship with general self-efficacy and coping style of delinquent teenagers Method:228 delinquent teenagers in jails completed a serial of questionnaires including emotional intelligence scale (EIS), general s elf-efficacy scale (GSES) and coping style scale Results:The me a n score of emotional intelligence of delinquents was lower than that aged matche d middle school students There was positive correlation between emotional inte l ligence and self-efficacy or coping style of delinquents But the emotional int e lligence of them had no relation to depression Conclusion:Emoti o nal intelligence of delinquent teenagers is lower than that of normal students o f the same age, it has some relation to self-efficacy and coping style of the pe rson