Caracterização de cereja-do-rio grande (Eugenia involucrata DC. ) e grumixama (Eugenia brasiliensis LAM. ), frutos nativos da Mata Atlântica, quanto a compostos voláteis e precursores / Volatile compounds and precursors characterization of the Grumixama (Eugenia brasiliensis LAM. ) and Cereja-do-Rio-Grande (Eugenia involucrata DC. ), atlantic forest native fruits

Mesmo reduzida e fragmentada, o vasto bioma da Mata Atlântica abriga milhares de plantas. Como destaque, tem-se as espécies frutíferas, aos quais podem ser atribuídas um importante valor para a segurança alimentar, nutricional e sociocultural. Entre elas, têm-se a cereja-do-rio grande (Eugenia involucrata DC.) e a grumixama (Eugenia brasiliensis Lam.), caracterizadas pela polpa de sabor doce-acidulado, sendo muito apreciadas e utilizadas tanto in natura, quanto no preparo de doces, xaropes, licores e geleias. Uma das características determinantes para o sucesso e aceitação destes frutos pelo consumidor, são os atributos de qualidade sensorial. As propriedades aromáticas dos frutos dependem da potência individual dos voláteis e a concentração de cada um, bem como a combinação com outros compostos. Todavia, apesar do grande potencial de mercado, devido às características nutricionais, fitoterápicas, potencial funcional e ao sabor exótico, os plantios existentes destas são oriundos de multiplicação por sementes, resultando em plantas desuniformes quanto as características de produção e qualidade. Neste sentido, o presente trabalho teve como objetivo identificar metabólitos voláteis que confiram características sensoriais desejáveis aos frutos. Auxiliando na identificação de plantas que produzem frutos com voláteis de interesse para o sabor, o que permitirá a clonagem e propagação de plantas com homogeneidade na produção. Os compostos voláteis foram analisados em triplicata, de acordo com o método de microextração em fase sólida (SPME, do inglês Solid Phase Microextraction). Os resultados mostraram que os grupos de frutos das diversas regiões se diferenciaram quanto a composição dos metabolitos voláteis, bem como na abundância destes compostos. Observou-se também uma variação de composição entre as árvores da mesma região demonstrando tal irregularidade ocasionada pela propagação por sementes. A maioria de compostos voláteis produzidos foram identificados como terpenos, sendo estes já conhecidos pela importância no flavor em frutos. Desta forma, conhecer o aroma fornecerá um conjunto de dados que são subsídios para outros pesquisadores trabalharem em suas diversas áreas buscando características necessárias para o sucesso da comercialização, ocasionando no incentivo ao cultivo e valorização da riqueza nacional, no âmbito das espécies frutíferas, com vistas à proteção ambiental e em defesa da biodiversidade brasileira

The Atlantic Forest harbors thousands of plants despite of its reduced and fragmented character. It is important to highlight the fruit species which hold attributed and important value for food and socio-cultural security. Among them, there are the big cherry (Eugenia involucrata DC.) And the grumixama (Eugenia brasiliensis Lam.), fruit with sweet-acidulated flavor, which is much appreciated and used in the preparation of sweets, syrups, liqueurs, and jellies. One of the determining characteristics for the success and acceptance of these fruits by the consumer are the attributes of sensorial quality. The aromatic properties of the fruits depend on the individual potency of the volatiles and the concentration in each one of them, as well as the combination with other compounds. Despite of the great market potential due to the nutritional, phytotherapic and exotic flavor characteristics, the existing plantations of these fruits are originated from seed multiplication, resulting on uneven plants in terms of production and quality characteristics. In this sense, the presented work below was aimed to identify volatile metabolites that confer desirable sensorial characteristics to the fruits. The volatile compounds were analyzed in triplicate according to the Solid Phase Microextraction (SPME) method. The results showed that the fruit groups from different regions differed in terms of the composition of volatile metabolites, as well as in the abundance of these compounds. There was also a variation of composition among the trees of the same region which demonstrated such heterogeneity caused by seed propagation. Most volatile compounds produced were identified as terpenes which are known for playing an important role in the flavor of fruits. In this way, by knowing the aroma, a set of data will be provided and used as an allowance for other researchers who are working in the various areas related to the pursue of the necessary characteristics for the commercial success, resulting on the motivation to cultivate and value the forest

Multivariate optimization of a HS-SPME/GC-MS technique for the characterization of volatile compounds present in Hedeoma multiflorum Benth / Optimización Multivariada de una técnica HS-SPME/GC para la caracterización de los compuestos volátiles presentes en Hedeoma multiflorum Benth

The aim of the present work was to optimize the main experimental variables of a procedure using HS-SPME/GC-MS as the analytical methodology to establish the profile of the volatile compounds present in aerial parts of Hedeoma multiflorum Benth. The influence of the type of fiber, equilibrium time, extraction time and extraction temperature on the composition of the volatile compounds was determined using response surface methodology (RSM), and the parameters of the models were corroborated by multiple linear regressions. The results showed that the regression models generated adequately explained the data variation and represented the relationships between the parameters and their responses. The optimal analysis conditions from the contour plots were established (DVB/CAR/PDMS fiber, with a 10 min equilibrium time, 10 min extraction time, and 40°C). Under these conditions, 41 volatile components in the whole plant were determined, which represents more than those reported using hydrodistillation.

El objetivo del presente trabajo fue optimizar las principales variables experimentales de un procedimiento HS-SPME/GC para establecer el perfil de compuestos volátiles presentes en la parte aérea de Hedeoma multiflorum Benth. Se determinó la influencia de las variables tipo de fibra, tiempo de equilibrio, tiempo de extracción y temperatura de extracción sobre la composición de los volátiles, utilizando una met odología de superficie de respuesta (RSM) y los parámetros del modelo se corroboraron por regresión lineal múltiple. Los resultados demostraron que los modelos de regresión generados explican adecuadamente la variación de los datos y representaron significativamente las relaciones reales entre los parámetros y sus respuestas. Las condiciones óptimas de análisis fueron establecidas (DVB/CAR/PDMS, con un tiempo de equilibrio de 10 minutos, un tiempo de extracción de 10 minutos y trabajando a 40°C). Utilizando esta metodología, se determinaron 41 componentes volátiles en planta entera, más que los reportados mediante hidrodestilación.

Prospecção de compostos orgânicos voláteis e seus efeitos na auto-regulação fisiológica em cianobactérias / Prospection of volatile organic compounds and their effects on physiological self-regulation in cyanobacteria

Apesar dos diversos estudos sobre a presença de cianobactérias e a correlação entre fatores ambientais que influenciam ou desencadeiam florações, é ainda incipiente a informação sobre o controle fisiológico e bioquímico da produção de metabólitos secundários, cianotoxinas e compostos orgânicos voláteis (COVs) nestes organismos. Os COVs mais comumente encontrados em cianobactérias são a geosmina e o 2- metil-isoborneol, compostos que resistem ao tratamento convencional da água, causam mau cheiro e alteram seu gosto, além de bioacumular em peixes e moluscos. Estudos sobre possíveis sistemas de competição (alelopatia) entre linhagens de cianobactérias, ou entre elas e outros organismos, podem contribuir para elucidação do papel da produção de COVs por cianobactérias. Dessa forma, os objetivos deste projeto foram (i) prospectar a produção de COVs e seus efeitos na auto-regulação fisiológica em cianobactérias mantidas em laboratório; e (ii) desenvolver um método analítico, por microextração em fase sólida (SPME) e cromatografia em fase gasosa com detecção por espectrometria de massas (GC-MS), para a determinação destes compostos. Foram realizados ensaios para avaliar os perfis de produção dos COVs em duas linhagens de M. aeruginosa em diferentes fases de crescimento, sob diferentes intensidades luminosas (50, 150 e 250 ?µmol.fótons.m-2.s-1) e também ao longo do ritmo circadiano, avaliando a influência dos períodos claro e escuro. Para avaliar efeitos alelopáticos, exsudatos de uma linhagem de M. aeruginosa produtora de microcistinas foram testados em culturas de outra linhagem de M. aeruginosa não produtora de toxinas por meio de técnicas tradicionais de cultivo com monitoramento do crescimento. Na análise da produção de COVs, por GC-MS, observou-se que se destacam, majoritariamente, os compostos α-ciclocitral, ß-ciclocitral e ß-ionona, sendo o ß-ciclocitral o mais abundante, em todas as condições testadas, para as ambas as linhagens estudadas. A linhagem não toxigênica, no entanto, apresentou produção mais elevada de todos os compostos identificados. Dentre as intensidades luminosas testadas, a intensidade de 250 µmol.fótons.m-2s-1 foi a que apresentou a maior taxa de crescimento para a linhagem LTPNA 08 e relação negativa entre o aumento da irradiância e a produção de ß-ciclocitral. Foram identificadas, também, variações na produção dos compostos α-ciclocitral, ß-ciclocitral e ß-ionona nas linhagens ao longo do ritmo circadiano, sendo as maiores concentrações encontradas no período escuro. Observou-se morte celular e redução na produção de COVs 24 horas após adição de exsudatos pertencentes à linhagem de M. aeruginosa toxigênica em cultivos da linhagem não-toxigênica. Sendo assim, pode-se inferir que a produção dos COVs pode sofrer alterações qualitativas e quantitativas dependendo do estímulo ambiental presente, tanto por interações bióticas (com outros organismos e ritmo circadiano), quanto por fatores abióticos (intensidade luminosa)

There are several studies on the presence of cyanobacteria and the correlation between environmental factors that may influence or trigger blooms. However, information concerning the physiological and biochemical control of the production of secondary metabolites, toxins and volatile organic compounds (VOC) by cyanobacteria is poorly understood. Geosmin and 2-methyl-isoborneolare are commonly found VOC in cyanobacteria, they resist to conventional water treatment and can cause bad smell and taste in the final water. In addition, VOC can bioaccumulate in fish and shellfish. Studies on possible competition systems (allelopathy) either among strains of cyanobacteria or among them and other organisms such as green microalgae, may help to elucidate the role of VOC production by cyanobacteria. Thus, the main objectives of this study are: (i) prospect the production of VOCs and their effects on physiological self-regulation in cyanocrobacteria kept in the laboratory; and (ii) to develop an analytical method, by solid phase microextraction (SPME) and gas chromatography with mass spectrometry detection (GC-MS), for the determination of these compounds. The assays were carried out to evaluate the production profiles of VOCs in two strains of M. aeruginosa at different growth stages under different light intensities (50, 150 and 250 µmol.fótons.m-2.s-1) and also along of the circadian rhythm, evaluating the influence of light and dark periods. To assess allelopathic effects, exudates from a microcystin-producing strain of M. aeruginosa were tested on cultures of another non-toxin producing M. aeruginosa strain by traditional growth monitoring culture techniques. In the analysis of VOC production by GC-MS, it was observed that α-cyclocyclal, ß-cyclocyclal and ß-ionone compounds were the most prominent, with ß-cyclocitral being the most abundant in all conditions tested, for both strains studied. The non-toxigenic lineage, however, showed higher production of all the identified compounds. Among the light intensities tested, the intensity of 250 µmol.fótons.m-2s-1 was the one with the highest growth rate and positive relation between the irradiance increase and the ß-cyclocitral production. Variations in the production of the α-cyclocyclal, ß-cyclocyclal and ß-ionone compounds were also identified in the lines along the circadian rhythm, being the highest concentrations found in the dark period. Cell death and reduction in VOC production were observed 24 hours after addition of exudates belonging to the toxigenic M. aeruginosa lineage in cultures of the non-toxigenic lineage. Thus, it can be inferred that the production of VOCs can undergo qualitative and quantitative changes depending on the environmental stimulus present, both by biotic interactions (with other organisms and circadian rhythm) and by abiotic factors (luminous intensity)

Volatile compounds profile of Bromeliaceae flowers / Perfil de compuestos volátiles de las flores en las Bromeliaceae

Abstract:Volatile compounds play a vital role in the life cycle of plants, possessing antimicrobial and anti-herbivore activities, and with a significant importance in the food, cosmetic, chemical, and pharmaceutical industry. This study aimed to identify the volatile compounds emitted by flowers of thirteen species belonging to four genera of Bromeliaceae, using headspace solid-phase micro-extraction and detection by gas chromatography-mass spectrometry. A total of 71 volatile compounds belonging to nine chemical groups were identified. The compounds identified represented more than 97 % of the major components in Aechmea bicolor, Ae. bromeliifolia, Ae. distichantha, Ae. fasciata, and Vriesea friburgensis. In the Ananas varieties, over 99 % of the components were identified, and around 90 % in V. simplex. V. friburgensis presented the largest diversity of volatiles with 31 compounds, while Alcantarea nahoumii presented only 14. All three Ananas varieties presented the same 28 compounds in relatively similar abundance, which has been confirmed by principal component analysis. Current taxonomy and pollination syndrome studies available can adequately explain the variation in volatile compounds among species. Rev. Biol. Trop. 64 (3): 1101-1116. Epub 2016 September 01.

ResumenLos compuestos volátiles tienen un papel vital en el ciclo de vida de las plantas. Poseen actividad antimicrobiana y anti-herbivoría biológica y una gran importancia en la industria de alimentos, cosméticos, perfumes, productos químicos y farmacéuticos. Este estudio tuvo como objetivo identificar los compuestos volátiles de trece flores de especies, pertenecientes a cuatro géneros de Bromeliaceae utilizando microextracción en fase sólida mediante cromatografía de gases hifenada con espacio de cabeza acoplada a espectrometría de masas. Se han identificado setenta y un diferentes compuestos volátiles pertenecientes a nueve grupos. Los compuestos identificados representaron más del 97 % de los componentes principales en Aechmea bicolor, Ae. bromeliifolia, Ae. distichantha, Ae. fasciata, Vriesea friburgensis, 99 % en las variedades de Ananas y 90 % en V. Simplex. V. friburgensis mostró la mayor diversidad de compuestos volátiles con 31, mientras que en Al. nahoumii se han encontrado sólo 14 compuestos. Las tres variedades de Ananas presentan los mismos 28 compuestos en cantidades relativamente similares, lo que se confirmó por el análisis de componentes principales. Estudios taxonómicos y síndromes de polinización disponibles podrían explicar la variación de los compuestos volátiles entre especies.

Determination of volatile organic compounds of tagetes Argentina Cabrera (Asteraceae) using HS-SPME analysis / Determinación de compuestos orgánicos volátiles de tagetes Argentina Cabrera (Asteraceae) utilizando análisis por HS-SPME

A headspace solid-phase microextraction (HS-SPME) method followed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID) is described for the analysis of volatile compounds in Tagetes argentina Cabrera. The composition of the totality of the aerial parts of the plant (whole plant) and the inflorescences, leaves and stems was studied separately using HS-SPME. As a result, 53 compounds were determined, of which 39 were identified. The major components were: cis-tagetenone, trans-tagetenone, trans-tagetone and cis-tagetone.Using a much smaller amount of samples, a shorter extraction time and a very simple procedure, the HS-SPME method can achieve similar or better results than those obtained by EO analysis. In conclusion, the HS-SPME method is simple, rapid, effective and free of solvent, and can be used for the analysis of volatile compounds in samples of different populations of T. Argentina.

Se realizó el análisis de los componentes volátiles de T. argentina Cabrera utilizando el método de micro-extracción en fase sólida del espacio de cabeza con análisis posterior por cromatografía de gases acoplada a espectrometría de masas y por cromatografía de gases con detección por ionización de llama. Se estudio la composición de la totalidad de las partes aéreas de la planta (planta entera) como así también de las inflorescencias, hojas y tallos por separado empleando el método de HS-SPME. Como resultado, se determinaron 53 compuestos de los cuales 39 fueron identificados. Los componentes mayoritarios fueron: cis-tagetenona, trans-tagetenona, trans-tagetona and cis-tagetona. Utilizando una muy pequeña cantidad de muestra, un corto periodo de tiempo y un procedimiento muy simple se lograron similares o mejores resultados a aquellos reportados mediante el análisis del aceite esencial. En conclusión, el método de HS-SPME es simple, rápido, efectivo, libre de la utilización de solventes y puede ser fácilmente implementado para el análisis de componentes volátiles provenientes de muestras de diferentes poblaciones de T. Argentina.

[Optimization of solid phase micro-extraction [SPME] for monitoring occupational exposure to ethyl benzene]

Analytical methods for volatile organic compounds [VOCs] in different samples need extraction of compounds by applying hazardous solvents. Solid phase micro-extraction [SPME] is a solvent-free equilibrium extraction method in which proper calibration can allow quantitative determinations of VOCs at a very good sensitivity without the use of any organic solvent. VOCs are generally present in urine only at trace levels therefore a sensitive procedure is needed for their trace determinations. Throughout this study headspace solid phase micro-extraction [HS-SPME] was followed by GC-FID for ethyl benzene in spiked urine was optimized. In this study the parameters influencing SPME and gas chromatography of ethyl benzene including extraction time temperature desorption temperature desorption time salt addition sample pH sample volume and sample agitation were investigated. Extraction procedure was performed at 30°C for 6 min using 0.2 gmL[-1] of NaCl in the sample solution. The sample volume and sample pH were optimized at 5 ml and 7 [neutral pH] respectively. Desorption of the ethyl benzene was carried out for 60 sec. at 250°C. The method was also validated with three different spiked urine samples and illustrated an appropriate reproducibility over six consecutive days as well as six within-day experiments. During this investigation parameters of accuracy linearity and detection limits of the procedure were also evaluated. The developed method of HS- SPME-GC-FID proved to be a simple convenient and practical procedure and was successfully used for measuring of ethyl benzene in spiked urine