Linalool, a Piper aduncum essential oil component, has selective activity against Trypanosoma cruzi trypomastigote forms at 4°C

BACKGROUND Recent studies showed that essential oils from different pepper species (Piper spp.) have promising leishmanicidal and trypanocidal activities. OBJECTIVES In search for natural compounds against Trypanosoma cruzi, different forms of the parasite were incubated for 24 h at 28ºC or 4ºC with Piper aduncum essential oil (PaEO) or its main constituents linalool and nerolidol. METHODS PaEO chemical composition was obtained by GC-MS. Drug activity assays were based on cell counting, MTT data or infection index values. The effect of PaEO on the T. cruzi cell cycle and mitochondrial membrane potential was evaluated by flow cytometry. FINDINGS PaEO was effective against cell-derived (IC50/24 h: 2.8 μg/mL) and metacyclic (IC50/24 h: 12.1 μg/mL) trypomastigotes, as well as intracellular amastigotes (IC50/24 h: 9 μg/mL). At 4ºC - the temperature of red blood cells (RBCs) storage in blood banks - cell-derived trypomastigotes were more sensitive to PaEO (IC50/24 h = 3.8 μg/mL) than to gentian violet (IC50/24 h = 24.7 mg/mL). Cytotoxicity assays using Vero cells (37ºC) and RBCs (4ºC) showed that PaEO has increased selectivity for cell-derived trypomastigotes. Flow cytometry analysis showed that PaEO does not affect the cell cycle of T. cruzi epimastigotes, but decreases their mitochondrial membrane potential. GC-MS data identified nerolidol and linalool as major components of PaEO, and linalool had trypanocidal effect (IC50/24 h: 306 ng/mL) at 4ºC. MAIN CONCLUSION The trypanocidal effect of PaEO is likely due to the presence of linalool, which may represent an interesting candidate for use in the treatment of potentially contaminated RBCs bags at low temperature.

Essential oil from Chenopodium ambrosioides L: secretory structures, antibacterial and antioxidant activities / Óleo essencial de Chenopodium ambrosioides L: estruturas secretoras, atividade antibacteriana e antioxidante

The aim of this study was to evaluate the antibacterial and antioxidant activities of essential oil from Chenopodium ambrosioides L. and to determine its secretory structures. The essential oil was extracted through the hydrodistillation technique using a modified Clevenger apparatus (2 hours) and chemically characterized by GC/MS and GC-FID. The antioxidant activity was determined by monitoring the reduction of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and by the oxidation of the ß-carotene/linoleic acid system. The evaluation of antibacterial activity was performed by the agar cavity diffusion technique using the microorganisms Staphylococcus aureus, Listeria monocytogenes, Escherichia coli and Salmonella Cholerasuis. The characterization of trichomes was accomplished by Scanning Electron Microscopy (SEM) and histochemical tests with Nadi and Sudan IV reagents. The antioxidant activity demonstrated by the ß-carotene/acid linoleic test, with IC50 = 455.7 µg mL-1. This oil also presented antibacterial activity for both Gram-negative and Gram-positive bacteria. The minimal inhibitory concentration ranged 62.5 to 250 µL mL-1. The presence of terpenes in the glandular trichomes was observed, suggesting that the essential oil is secreted by these structures.

Objetivou-se neste trabalho avaliar as atividades antibacteriana e antioxidante do óleo essencial de Chenopodium ambrosioides L. e determinar as suas estruturas secretoras. A extração do óleo essencial foi realizada pelo método de hidrodestilação, utilizando o aparelho de Clevenger modificado com duração de 2 horas, sendo, posteriormente, analisado por CG/EM e CG-DIC. A atividade antioxidante foi determinada monitorando-se a redução do radical livre DPPH (2,2-difenil-1-picril-hidrazila) e utilizando o ensaio de oxidação do sistema ß-caroteno/ácido linoleico. A avaliação da atividade antibacteriana foi realizada por meio da técnica difusão cavidade em ágar, utilizando os micro-organismos Staphylococcus aureus, Listeria monocytogenes, Escherichia coli e Salmonella Cholerasuis. A caracterização dos tricomas foi realizada por Microscopia Eletrônica de Varredura (MEV) e pelos testes histoquímicos com os reagentes de Nadi e Sudan IV. A atividade antioxidante foi evidenciada pelo teste ß-caroteno/ácido linoleico, com CI50 455,7 µg mL-1. O óleo também apresentou atividade antibacteriana tanto para bactérias Gram -negativas como para Gram-positivas. A concentração mínima inibitória do mesmo variou entre 62,5 e 250 µL mL-1. Constatou-se a presença de compostos terpênicos nos tricomas glandulares, inferindo-se que o óleo essencial seja secretado nessas estruturas.

Clotting and fibrinogenolysis inhibition by essential oils from species of the Asteraceae family

ABSTRACT Essential oils are pharmacologically active and unexplored compounds. The inhibitory properties of essential oils from Baccharis dracunculifolia, Conyza bonariensis, Tithonia diversifolia and Ambrosia polystachya were evaluated in the coagulation and fibrinogenolysis induced by snake venoms. The essential oil from Conyza bonariensis extended the clotting time of Lachesis muta from 52.2 to 115.2 seconds and that of Bothrops moojeni from 108.3 to 2340.0 seconds, when pre-incubated with the venoms. The longest clotting times for Bothrops atrox venom were observed after incubation with the essential oils from Conyza bonariensis and Tithonia diversifolia: the times increased from 100.8 to 264.0 and 227.7 seconds, respectively. The prior incubation of the essential oils with plasma and subsequent addition of Lachesis muta venom resulted in a pro-clotting effect. The oils from Ambrosia polystachya and Baccharis dracunculifolia caused 100% of inhibition on the fibrinogenolysis induced by Bothrops moojeni and Lachesis muta venoms (the oils were previously incubated with the venom). The results indicate that the essential oils show promise as adjuvants for the treatment of snakebites.

Confrontando estruturas de valores: um estudo comparativo entre PVQ-40 e PVQ-21 / Confronting structures of values: a comparative study between PVQ-40 and PVQ-21

Esforços têm sido realizados para desenvolver escalas de mensuração capazes de traduzir o constructo e a estrutura de valores. Entre as existentes estão as escalas SVS - Schwartz Value Survey e o Portrait Values Questionnaire com 40 e 21 itens (respectivamente PVQ-40 e PVQ-21). As duas formas desse último questionário apresentam aplicabilidade mais ampla, por possuírem uma menor quantidade de itens e terem os itens redigidos de forma menos abstrata do que a SVS. Não foram encontrados, no entanto, estudos que comparem as duas escalas quanto à estrutura de valores obtida a partir de sua aplicação, objetivo a que este estudo se propôs a alcançar. A pesquisa foi realizada com uma amostra de 217 estudantes universitários, aos quais foram aplicadas as escalas PVQ-40 e PVQ-21, em dois momentos distintos. Os dados foram tratados mediante Análise de Escalonamento Multidimensional Confirmatória Fraca. Os resultados indicaram que ambas as escalas são equivalentes quanto à estrutura de valores bidimensional e bipolar, porém foram encontradas divergências entre ambas quanto à distribuição no espaço dos valores dos tipos Estimulação, Autodeterminação, Poder e Realização. (AU)

Several measurement scales have been developed in order to translate constructs and their value structure. Among these are the Schwartz's Values Survey (SVS) and the Portrait Values Questionnaire with 40 and 21 items, respectively (PVQ-40 and PVQ-21). The two forms of the questionnaire allow a wider use because they have showed fewer and less abstract items compared to the SVS, however, there have not been found studies that compare both instruments regarding their value structure. Therefore, this is the objective of the present study. A sample of 217 university students answered the PVQ-40 and the PVQ-21 at two different moments in time. The data were analyzed by Confirmatory Multidimensional Scaling. The results indicate that both scales are equivalent in terms of bidimensional and bipolar value structures, however, differences were found with regard to the spatial distribution of values measuring Stimulation, Self-Direction, Power and Achievement. (AU)

Peculiaridades da estrutura de valores básicos dos brasileiros / Characteristic features of brazilians' basic values

A teoria de Valores Básicos, validada em diversos países, tem apresentado diferentes configurações empíricas, de acordo com a população e amostra pesquisada. No Brasil, alguns estudos foram realizados, porém com amostras não representativas, não havendo convergência entre os resultados. Este trabalho teve como objetivo analisar a estrutura empírica dos valores dos brasileiros, a partir de uma amostra representativa, totalizando 3.774 respondentes. Os dados foram coletados face a face por meio de entrevistadores que aplicaram a escala Portrait Values Questionnaire (PVQ-21). O tratamento de dados consistiu na análise confirmatória do escalonamento multidimensional tendo por base uma matriz de desenho específica para aplicação à teoria de valores básicos. Com base em estudos anteriores, elaboraram-se três hipóteses de pesquisa quanto ao agrupamento e distribuição dos valores na estrutura empírica, as quais foram parcialmente corroboradas. Os valores de benevolência localizaram-se na parte interna do círculo e os de universalismo, na parte externa; os valores de hedonismo e estimulação associaram-se em uma única região; os valores de conformidade assumiram região adjacente aos valores de tradição e segurança. A distribuição circular dos valores sugere que a matriz empírica dos valores dos brasileiros tende a assumir características de sociedades econômica e socialmente desenvolvidas...

The Basic Values Theory has been validated in various countries. Depending on the respective population and sample, however, somewhat different empirical configurations have been found. In Brazil, some studies have been conducted, though with unrepresentative samples, and their results do not converge. This study aimed to analyze the empirical structure of Brazilians' values, using a representative sample, with 3,774 respondents. Data were collected face-to-face by interviewers who applied the Portrait Values Questionnaire (PVQ-21). Data analysis consisted of confirmatory multidimensional scaling based on a specific design matrix derived from the Basic Values Theory. Based on previous studies, three research hypotheses were proposed that related to the grouping and distribution of the values in the empirical structures. These hypotheses were partially supported. Benevolence values were located inside the circle, and those of Universalism toward the outside. The values of Hedonism and Stimulation collapsed into a single region. Conformity values filled the region adjacent to the values of Tradition and Security. The circular distribution of values suggests that the empirical structure of Brazilians' values tends to assume features of economically and socially developed societies...