Preparation of a ε-caprolactonic diterpenoid derivate by unexpected oxidative cleavage/lactonization of 2-oxoaustroeupatol.

From aerial parts of Austroeupatorium inulifolium was isolated the ent-nor-furano triol labdane austroeupatol 1. The compound 1 was treated with IBX showing an unexpected selectivity at the potentially oxidizable sites of the substrate yielding the 2-oxoaustroeupatol (2) and 2,19-dioxoaustroeupatol (3). The treatment of 2 with sodium periodate yields a heterocyclic derivative (ε-caprolactone derivate 4) formed by oxidative cleavage and unexpected intramolecular attack of the hydroxymethylene (C-19) oxygen to the ketonic carbon (C-2). A plausible mechanistic pathway for the obtention of compound 4 is proposed.

Actividad antifúngica del aceite volátil de Hedyosmum sp, frente a especies del género Candida / Antifungal activity of the volatile oil of Hedyosmum sp, Against species of the genus Candida

El objetivo del estudio fue determinar la actividad antifúngica del aceite volátil de las partes aéreas de la especie vegetal Hedyosmum sp., frente al complejo Candida albicans, C. glabrata, C. tropicalis y C. parapsilosis. El material vegetal se recolectó del bosque natural Jacarón, Provincia de Chimborazo, Ecuador. La extracción del aceite volátil se realizó por hidrodestilación, obteniéndose un rendimiento de 0,09%. La actividad antifúngica fue estudiada mediante el método de difusión en agar y los resultados se interpretaron mediante detección-medición de halos de inhibición y concentración mínima inhibitoria. El estudio se realizó partiendo del aceite puro y diluciones con dimetil sulfóxido. Los resultados se validaron mediante controles positivos (Fluconazol) y negativos (dimetil sulfóxido). El aceite puro mostró actividad antifúngica frente a C. albicans, C. tropicalis, C. parapsilosis, pero no frente a C. glabrata. Mientras que, la actividad antifúngica determinada empleando diluciones del aceite permitió establecer la concentración mínima inhibitoria para C. tropicalis, C. parapsilosis, en 0,25x106 µg/mL y para C. albicans en 0,5x106 µg/mL. Estos resultados concluyeron que el aceite volátil de Hedyosmum sp., presenta actividad antifúngica poco significativa frente a tres de las cuatro especies de Candida estudiadas

The objective of the study was to determine the antifungal activity of the volatile oil of the aerial parts of the plant species Hedyosmum sp., against Candida albicans, C. glabrata, C. tropicalis and C. parapsilosis complex. The plant material was collected from the Jacarón natural forest, Chimborazo Province, Ecuador. The extraction of the essential oil was carried out by hydro-distillation, obtaining a yield of 0.09%. Antifungal activity was studied by means of the diffusion in agar method and the results were interpreted by detection-measurement of inhibition halos and minimum inhibitory concentration. The study was carried out starting from the pure oil and dilutions with dimethyl sulfoxide. The results were validated by positive controls (Fluconazole) and negative controls (dimethyl sulfoxide). The pure oil showed antifungal activity against C. albicans, C. tropicalis, and C. parapsilosis complex, but not against C. glabrata. While, the antifungal activity determined using dilutions of the oil allowed establishing the minimum inhibitory concentration for C. tropicalis, C. parapsilosis complex, at 0,25x106 µg/mL and for C. albicans at 0,5x106 µg/mL. These results concluded that the volatile oil of Hedyosmum sp., Presents little antifungal activity against three of the four Candida species studied

COMPONENTES QUÍMICOS Y ACTIVIDAD ANTIMICROBIANA DEL ACEITE ESENCIAL DE Lasiocephalus ovatus (Asteraceae) QUE CRECE EN ECUADOR / Chemical components and antimicrobial activity of the essential oil of Lasiocephalus ovatus (Asteraceae) that grows in Ecuador

RESUMEN Ecuador es uno de los países más ricos en biodiversidad y endemismo del mundo, y cerca de 3200 especies de plantas tienen usos medicinales. El objetivo de esta investigación fue evaluar la composición química y el efecto antimicrobiano del aceite esencial de Lasiocephalus ovatus Schltdl. (Asteraceae) colectada en la provincia de Chimborazo, Ecuador. Las partes aéreas de L. ovatus fueron sometidas a hidrodestilación para obtener el aceite esencial, el cual fue analizado mediante cromatografía de gases acoplada a espectrometría de masas. La actividad fue evaluada frente a cinco bacterias y una levadura usando la técnica de microdilución en caldo en microplacas de 96 pozos. El rendimiento del aceite fue de 0,05 % y 27 compuestos fueron identificados, representando 95,45 % de la composición total con un elevado contenido de monoterpenos oxigenados (52,17 %). Los compuestos mayoritarios fueron alcanfor (40,48 %) y 1,2,5,5-tetrametil-1,3-ciclopentadieno (11,90 %), seguido por p-menta-1,5-dien-8-ol (5,23 %) y 1,6-dimetilhepta-1,3,5-trieno (4,69 %). Las bacterias más sensibles a la acción del aceite fueron Staphylococcus aureus ATCC 25923 y Escherichia coli ATCC 25922 con concentraciones mínimas inhibitorias de 200-400 µg/mL y bactericidas de 800 µg/mL. La inhibición antimicrobiana frente a las bacterias Enterococcus faecalis ATCC 29212, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 700603 y la levadura Candida albicans ATCC 10231 fue baja, con un rango de concentración mínima inhibitoria de 800 a 6400 µg/ mL. Este reporte representa un primer análisis de la actividad antimicrobiana del aceite de L. ovatus, por lo tanto, una contribución importante al estudio del género Lasiocephalus.

ABSTRACT Ecuador is one of the richest countries in biodiversity and endemism in the world, and nearly 3200 plant species have medicinal uses. The aim of this investigation was to evaluate the chemical composition and the antimicrobial effect of essential oil of Lasiocephalus ovatus Schltdl. (Asteraceae) collected at Chimborazo Province, Ecuador. The aerial parts of L. ovatus were subjected to hydrodistillation to obtain essential oil, which was analyzed by gas chromatography coupled to mass spectrometry. The activity was evaluated against five bacteria and one yeast using the broth microdilution technique in 96-well microplates. The oil yield was of 0.05 %, and 27 compounds were identified, representing 95.45 % of the total composition with a high content of oxygenated monoterpenes (52.17%). The main compounds were camphor (40.48 %) and 1,2,5,5-tetramethyl-1,3-cyclopentadiene (11.90 %) followed by p-mentha-1,5-dien-8-ol (5.23 %) and 1,6-dimethylhepta-1,3,5-triene (4.69 %). The antimicrobial effect of the essential oil was major against Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922 with minimum inhibitory concentrations of 200-400 µg/mL and bactericidal of 800 µg/mL. Antimicrobial inhibition against the bacteria Enterococcus faecalis ATCC 29212, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 700603 and the yeast Candida albicans ATCC 10231 was low, with minimum inhibitory concentration ranging from 800 to 6400 µg/mL. This report represents a first study of the chemical composition and antimicrobial activity of the oil of L. ovatus, therefore, an important contribution to the study of the genus Lasiocephalus.

Caracterización química y actividad antibacteriana del aceite esencial de Mangifera indica L. de tres regiones de Venezuela / Chemical characterization and antibacterial activity of the essential oil of Mangifera indica L. in three regions of Venezuela / Caracterização química e atividade antibacteriana do óleo essencial de Mangifera indica L. em três regiões da Venezuela

Resumen El presente trabajo describe la caracterización química cuali-cuantitativa y la evaluación antibacteriana de los aceites esenciales (AE) presentes en las hojas de Mangifera indica L., los cuales fueron recolectados en los estados de Mérida (M), Barinas (B), y Portuguesa (P), en la República Bolivariana de Venezuela, empleando la técnica de la hidrodestilación, acoplada a la trampa de Clevenger, obteniéndose 0,1 mL (0,0025%), 1,4 mL (0,035%) y 1,0 mL (0,025%), respectivamente. Los AE se caracterizaron por el método de cromatografía de gases acoplado a espectrometría de masas (CG/EM). Se identificaron 30 compuestos en la muestra recolectada en M, 24 en B y 14 en P, siendo los principales en M: β-selineno (22,56%), α-gurjuneno (14,66%) y β-cariofileno (10 40%); en B: β-cariofileno (36,32%), α-humuleno (22,71%) y a-gurjuneno (21,43%); y en P: β -cariofileno (36,07%), a-gurjuneno (22,55%) y c -humuleno (21,24%). Debido al rendimiento, solo se determinó la actividad antibacteriana en los AE de B y P, por el método de difusión en agar con discos, frente a bacterias de referencia internacional (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 23357 y Pseudomonas aureginosa ATCC 27853). Ambos AE inhibieron el desarrollo de S. aureus y E. faecalis con una concentración inhibitoria mínima de 200 µL/mL y 300 µL/ mL, respectivamente. Este es el primer estudio comparativo y actividad antibacteriana del aceite esencial obtenido de las hojas de M. indica L. de tres regiones de la República Bolivariana de Venezuela.

Abstract The present work describes the qualitative-quantitative chemical characterization of essential oils (EO) present in the leaves of Mangifera indica L. which were collected in the states of Mérida (M), Barinas (B), and Portuguese (P), in the Bolivarian Republic of Venezuela, using the technique of hydrodistillation, coupled to the trap of Clevenger. Volumes of 0.1 mL (0.0025%), 1.4 mL (0.035%) and 1.0 mL (0.025%) were obtained, respectively. The essential oils were characterized by the method of gas chromatography coupled to mass spectrometry (GC/MS). 30 compounds in the sample collected in M, 24 in B and 14inP were identified, being the majority in the M: β -selinene (22,56%), α-gurjunene (14,66%) and β-caryophyllene (10 40%); en B: β-caryophyllene (36,32%), a-humulene (22,71%) and α-gurjunene (21,43%); and in P: β -caryophyllene (36.07%), α-gurjunene (22.55%) and a-humulene (21.24%). Due to the low yield, the antibacterial activity was determined in the EO of B and P, by the agar diffusion method with disks, by various international reference bacteria (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 23357, Pseudomonas aureginosa ATCC 27853). Both AE inhibited the development of S. aureus and E. faecalis with a minimum inhibitory concentration of 200 µL/ mL and 300 µL/mL, respectively. This is the first comparative study and antibacterial activity of the essential oil obtained from the leaves of M. indica L. in three regions in the Bolivarian Republic of Venezuela.

Resumo O presente trabalho descreve a caracterização química qualitativa e quantitativa e a avaliação antibacteriana dos óleos essenciais (EA) presentes nas folhas de Mangifera indica L., quais foram coletadas nos estados de Mérida (M), Barinas (B) e Português (P), na República Bolivariana da Venezuela, utilizando a técnica de hidro-destilação, acoplada à armadilha de Clevenger, obtendo 0,1 mL (0,0025%), 1,4 mL (0,035%) e 1,0 mL (0,025%), respectivamente. Os EAs foram caracterizados pelo método de cromatografia gasosa acoplado a espectrometría de massa (GC / MS). Foram identificados trinta compostos na amostra coletada em M, 24 em B e 14 em P, sendo os principais M: β -selineno (22,56%), α-gurjuneno (14,66%) e β -cariofileno (10 40%); em B: β -cariofileno (36,32%), α-humuleno (22,71%) e α-gurjuneno (21,43%); e em P: β -cariofileno (36,07%), a-gurjuneno (22,55%) e α-humuleno (21,24%). Devido ao rendimento, apenas a atividade antibacteriana nos EA de B e P foi determinada, pelo método de difusão em ágar com discos, contra bactérias de referência internacional (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 23357 e Pseudomonas aureginosa ATCC 27853). Ambos os EA inibiram o desenvolvimento de S. aureus e E. faecalis com uma concentração inibitória mínima de 200 µL/mL e 300 µL/mL, respectivamente. Este é o primeiro estudo comparativo e atividade antibacteriana do óleo essencial obtido das folhas de M. indica L. de três regiões da República Bolivariana da Venezuela.

Caracterización química y actividad antimicrobiana del aceite esencial de las hojas de Libanothamnus neriifolius (Asteraceae) / Chemical characterization and antimicrobial activity of the essential oil of the leaves of Libanothamnus neriifolius (Asteraceae)

El aceite esencial de las hojas frescas de Libanothamnus neriifolius (B. ex H) Ernst., fue obtenido por el método de hidrodestilación utilizando la trampa de Clevenger, obteniendo 1.8 mL (rendimiento 0.087%). El aceite esencial se caracterizó por el método de cromatografía de gases acoplado a espectrometría de masas (CG-EM), identificando como compuestos principales β-felandreno (29.04%), α-felandreno (19.86%), α-pineno (13.57%) y α-tujeno (12.35%). La actividad antimicrobiana se determinó por el método de difusión en agar con discos, frente a bacterias y levaduras de referencia internacional (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 23357, Pseudomonas aureginosa ATCC 27853, Candida albicans CDC-B385, Candida krusei ATCC 6258). El aceite esencial inhibió el desarrollo de S. aureus, C. albicans y C. Krusei, con un valor de Concentración Inhibitoria Mínima (CIM) de 50 μL/mL, 700 μL/mL y 500 μL/mL, respectivamente. Este es el primer reporte sobre actividad antimicrobiana para L. neriifolius y para el género Libanothamnus.

The essential oil of the fresh leaves of Libanothamnus neriifolius (B. ex H) Ernst. was obtained by the hydrodistillation method using the Clevenger trap, obtaining 1.8 mL (0.087% yield). The essential oil was characterized by the method of gas chromatography coupled to mass spectrometry (GC/MS), identifying as main compounds, that β-phelandrene (29.0%), α-phelandrene (19.9%), α-pinene (13.6%), and α-tujene (12.4%) were the most abundant constituents. Antimicrobial activity of the oil was tested Staphylococcus aureus ATCC25923, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 23357, Pseudomonas aureginosa ATCC 27853, Candida albicans CDC-B385, Candida krusei ATCC 6258 by the agar difusion method. It showed activity against S. aureus with MIC of 50 μL/mL. With respect to antifungic activity it was active against C. albicans and C. krusei with MIC of 700 μL/mL and 500 μL/mL respectively. This is the first report on the antimicrobial activity of this L. neriifolius and for the genere Libanothamnus.

Composición química y actividad antibacteriana del aceite esencial de Peperomia acuminata de los Andes venezolanos / Chemical composition and antibacterial activity of essential oil Peperomia acuminata from Venezuelan Andes

El género Peperomia (Piperaceae), es bien conocido por sus especies ornamentales y usos etnomedicinales. En el presente trabajo se describe la caracterización química y la actividad antibacteriana del aceite esencial de Peperomia acuminata Ruiz & Pav. proveniente del Estado Mérida Venezuela. El aceite esencial se obtuvo por hidrodestilación de las hojas y la separación de los componentes se realizó por Cromatografía de gases-Espectrometría de Masas (CG/EM). Se logró la elucidación de ocho compuestos (96,7%), siendo el 2E-dodecenal el componente mayoritario (65%) seguido de dodecanal (14,8%) y tetradecanal (9,2%). Esta investigación muestra el potencial del aceite esencial de P. acuminata frente a bacterias Gram positivas (Staphylococcus aureus ATCC 25923 y Enterococcus faecalis 29212), con un valor de Concentración inhibitoria mínima de 1μL/mL. Este es el primer reporte sobre la composición química del aceite esencial de esta especie, por lo tanto una contribución importante al estudio del género Peperomia.

The genus Peperomia (Piperaceae) is well known for its ornamental species and ethnomedicinal uses. This paper aims to chemically characterize the essential oil of Peperomia acuminata Ruiz & Pav. from Mérida State, Venezuela, and determine its microbiological activity. The essential oil is obtained by hydrodistillation of the leaves and the separation of the components was performed by gas chromatography-mass spectrometry (GC/MS). Eight compounds (96.7%) were elucidated in the oil. The 2E dodecenal was found to be the major component (65%) followed by dodecanal (14.8%) and tetradecanal (9.2%). The essential oil showed high specificity against Gram positive bacteria Staphylococcus aureus ATCC (25923) and Enterococcus faecalis (29212) with a Minimum Inhibitory Concentration of 1 µL/mL. This is the first report about chemical composition of the essential oil from this specie therefore an important contribution to the study of the genus Peperomia.

Chemical composition and biological activity of essential oil of achyrocline ramosissima briton ex rusby (asteraceae) / Composición química y actividad biológica del aceite esencial de achyrocline ramosissima britton ex rusby (asteraceae)

Essential oil from fresh aerial parts of Achyrocline ramosissima Britton ex Rusby (Asteraceae) collected in the Venezuelan Andes was obtained by hydrodistillation and analyzed by GC/MS. A yield of 0.10 percent w/v was afforded, and thirty seven components were identified by comparison of their retention indices (RI) and mass spectra with the Wiley GC-MS Library Data. The major components identified were rosifoliol (31.69 percent), beta-caryophyllene (8.61 percent), guaiol (3.95 percent), beta-eudesmol (3.33 percent) and selina-3,7 (11)-diene (2.99 percent). Antimicrobial activity of A. ramosissima essential oil was also evaluated against Gram positive, Gram negative bacterial strains and Candida albicans yeast. The results showed that, this oil is effective against Gram positive bacteria Staphylococcus aureus ATCC 6538 with MIC values ranging from 50 to 100 μg/mL and MBC values > 200 μg/mL as well as Bacillus subtilis CECT 39 with MIC values of 50 μg/mL and MBC of 100 μg/mL, however a low activity was observed against Gram negative bacterial strains, Pseudomonas aeruginosa AK 958, Escherichia coli CECT 99 and C. albicans yeast performing MIC and MBC values > 200 μg/mL. Cytotoxic activity was also determined against HeLa (cervix carcinoma), A-459 (lung carcinoma), MCF-7 (breast adenocarcinoma) human cancer cell lines and against normal Vero cells (African green monkey kidney), exhibiting antiproliferative effects with IC50 values of 28.2 μg/mL (HeLa cells). This is the first report regarding the chemical composition, antibacterial and cytotoxic activities of the essential oil from this species.

El aceite esencial de las partes aéreas frescas de Achyrocline ramosissima Britton ex Rusby (Asteraceae) recolectada en los Andes venezolanos fue extraído por hidrodestilación y analizado por CG/EM. Se obtuvo un rendimiento de 0,10 por ciento m/v, treinta y siete componentes fueron identificados por comparación de los índices de retención (IR) y sus espectros de masas con los datos de la biblioteca Wiley GC-MS. Los principales componentes identificados fueron rosifoliol (31,69 por ciento), beta-cariofileno (8,61 por ciento), guaiol (3,95 por ciento), beta-eudesmol (3,33 por ciento) y selina-3,7 (11)-dieno (2,99 por ciento). La actividad antimicrobiana del aceite esencial de A. ramosissima fue evaluada contra cepas bacterianas Gram positivas, Gram negativas y la levadura Candida albicans. Los resultados mostraron que el aceite esencial fue activo contra las bacterias Gram positivas Staphylococcus aureus ATCC 6538 con una CIM entre 50-100 μg/mL y CBM de valores > 200 μg/mL y Bacillus subtilis CECT 39 con CIM de 50 μg/mL y CBM de 100 μg/mL, sin embargo se observó una baja actividad contra las cepas bacterianas Gram negativas Pseudomonas aeruginosa AK 958, Escherichia coli CECT 99 y la levadura C. albicans cuyos valores de CIM y CBM fueron > 200 μg/mL. La actividad citotóxica fue determinada frente a las líneas celulares cancerígenas HeLa (carcinoma de cuello uterino), A-459 (carcinoma de pulmón), MCF-7 (adenocarcinoma de mama) y frente a las células normales Vero (células renales de mono verde), mostrando efectos antiproliferativos con valores de CI50 28.2 μg/mL frente a las células HeLa. Este es el primer reporte sobre la composición química, actividad antibacteriana y citotóxica del aceite esencial de esta especie.

Volatile Constituents of the Leaves of Aniba hostmanniana (Lauraceae) and their Antibacterial Activities.

The essential oil of Aniba hostmanniana (Nees) Mez, family Lauraceae, was obtained from fresh leaves by hydrodistillation. The chemical composition of the oil was assessed using gas chromatography with mass spectrometric detection (GC-MS). The antimicrobial activity of the essential oil was tested against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia) and the Gram-positive bacterium Staphylococcus aureus. GC-MS analysis revealed the presence of 35 compounds in the essential oil, the predominant ones being benzyl benzoate (29.3%), Δ-cadinene (12%), ß-caryophyllene (10.5%), bicyclogermacrene (5.9%), and α-copaene (3.9%). The oil showed activity against most of the bacterial strains studied.

Chemical composition of the essential oil of Gynoxys meridana from Mérida, Venezuela.

The volatile components from the fresh leaves of Gynoxys meridana Cuatrec. were obtained by hydrodistillation and analyzed by GC/MS. A total of 25 compounds, representing 99.3% of the oil, were identified. The dominant compounds were γ-curcumene (31.9%), fukinanolide (22.3%), ß-pinene (9.5%), α-phellandrene (7.1%) and α-pinene (5.7%).

Comparison of the chemical composition of Valeriana parviflora essential oils collected in the Venezuelan Andes in two different seasons.

The essential oils obtained by hydrodistillation of the aerial parts of Valerianaparviflora (Trevir) BM Vadillo, an endemic species of the Venezuelan Andes, collected from the same location in two different seasons (dry and rainy) of the year, were analyzed by GC/MS. The essential oil obtained during the dry season showed linalool (11.9%), eugenol (8.9%), p-menth-l-en-9-al (8.7%) and α-terpineol (7.7%) as main components, while the oil obtained from the rainy season collection showed o-xylol (16.2%), 3-methyl isovaleric acid (10.6%) and geranial (9.5%) as major compounds. Some of the differences in the composition of these oils might be due to the climatic conditions at the time of harvesting.

Composición química y evaluación de la actividad antifúngica del aceite esencial de corteza de Vismia baccifera var. dealbata / Chemical composition and evaluation of anti-fungal activity of essential oil from Vismia baccifera var. dealbata bark

El objetivo de este trabajo fue evaluar la susceptibilidad de levaduras del género Candida y el Complejo Cryptococcus neoformans al aceite esencial de Vismia baccifera var. dealbata. El aceite, procedente de Chiguará, estado Mérida-Venezuela, fue analizado por CG/ EM logrando la identificación de trece componentes, que constituyeron el 97,7% de la mezcla; tres de ellos se apreciaron como productos mayoritarios, representando el 70,4% de la totalidad (Óxido de cariofileno 31,4%, β-cariofileno 26,4% y α-zingibireno 12,6%). El ensayo de actividad antifúngica mostró que dicho aceite inhibió el crecimiento de varias cepas de los géneros Candida y el Complejo C. neoformans, evaluadas cualitativamente por difusión en agar con disco a una concentración de 1.000 μg/mL; se observaron halos de inhibición entre 8 y 12 mm, exhibiendo valores de CMI entre 1,6 y 1.000 μg/mL en el ensayo cuantitativo por el método “Spot on a lawn”. Los datos obtenidos fueron sometidos a análisis de varianza y la prueba de Tukey, obteniéndose una actividad inhibitoria relevante contra Candida krusei. Este estudio constituye el primer reporte, tanto de la composición química como de evaluación antifúngica del aceite esencial extraído a partir de especies del género Vismia.

The purpose of this study was to evaluate the susceptibility of Candida genus yeasts and the Cryptococcus neoformans Complex to essential oil from Vismia baccifera var. dealbata. This oil, obtained at Chiguará, Mérida State, was analyzed by GC/MS, which identified thirteen components that constituted 97.7% of the mixture; three of them were established as majority products, representing 70.4% of the total: (cariophyllene oxide 31.4%, β-cariophyllene 26.4%, and α-zingibirene 12.6%). The anti-fungal assay showed that this oil inhibited the growth of several Candida genus strains and of the C. neoformans Complex, qualitatively evaluated by agar disk diffusion at a 1,000 μg/ mL concentration; inhibition halos of a between 8 to 12 mm diameter were observed, showing MIC values between 1.6 and 1,000 μg/mL in the “Spot on a lawn” quantitative assay. The data obtained were submitted to ANOVA and Tukey’s test, demonstrating a relevant inhibitory activity against Candida krusei. This study constitutes the first report, both of the chemical composition and of the anti-fungal evaluation, of the essential oil extracted from Vismia genus species.

Chemical composition of the essential oil of Erechtites valerianaefolia from Mérida, Venezuela.

The volatile components from the leaves of Erechtites valerianaefolia (Wolf) DC. were obtained by hydrodistillation and analyzed by GC/MS. A total of 12 compounds, representing 99.8% of the oil, were identified. The dominant compounds were limonene (56.7%), myrcene (12.7%), trans-beta-farnesene (10.2%) and l-phellandrene (8.7%).

Chemical composition and evaluation of antibacterial activity of essential oils of Ageratina jahnii and Ageratina pichinchensis collected in Mérida, Venezuela / Composición química y evaluación de la actividad antibacteriana de los aceites esenciales de Ageratina jahnii y Ageratina pichinchensis recolectadas en Mérida,Venezuela

Essential oil from leaves of Ageratina jahnii (B.L.Rob.) R. M. King & H. Rob. and Ageratina pichinchensis (Kunth) R. M. King & H. Rob (Asteraceae) collected in January 2010 were analyzed by GC/MS. Oils extracted by hydrodistillation yielded 0.50 percent and 0.43 percent w/v, respectively. Fifteen and twenty five components were identified by comparison of their mass spectra with the Wiley GC-MS Library data and by their retention indices (RI). The major components identified in A. jahnii were beta-myrcene (37.6 percent, alpha-pinene (17.1 percent), limonene (8.8 percent and pentacosane (9.2 percent while for A. pichinchensis 8,9-epoxythymyl isobutyrate (20.2 percent, germacrene-D (19.8 percent, thymyl isobutyrate (10.8 percent, eupatoriochromene (6.5 percent) and encecalol (5.9 percent) were observed as main compounds. This is the first report regarding the essential oil composition and antibacterial activity of the essential oil of A. jahnii.

Aceites esenciales de las hojas de Ageratina jahnii (B.L.Rob.) R. M. King & H. Rob. y Ageratina pichinchensis (Kunth) R. M. King & H. Rob (Asteraceae) colectadas en enero 2010 fueron analizados por CG/EM. Los aceites extraídos por hidrodestilación produjeron 0,50 por ciento y 0,43 por ciento p/v de rendimiento, respectivamente. Quince y veinticinco compuestos fueron identificados por comparación de sus espectros de masas con la base de datos de la librería Wiley CG/EM y por sus índices de retención (IR). Los compuestos identificados como majoritarios en A. jahnii fueron beta-mirceno (37,6 por ciento), alfa-pineno (17,1 por ciento, limoneno (8.8 por ciento y pentacosano (9,2 por ciento mientras para A. pichinchensis isobutirato de 8,9-epoxitimilo (20,2 por ciento, germacreno-D (19,8 por ciento, isobutirato de timilo (10,8 por ciento), eupatoriocromeno (6,5 por ciento y encecalol (5,9 por ciento) fueron observados como compuestos mayoritarios. Este es el primer reporte sobre la composición química y actividad antibacteriana del aceite esencial de A. jahnii.

Essential oil composition and antibacterial activity of Monticalia greenmaniana (Asteraceae).

The essential oils from fresh aerial parts of Monticalia greenmaniana (Hieron) C. Jeffrey (Asteraceae) collected in March, were analyzed by GC/MS. Oil yields (w/v) of 0.1% (flowers), 0.07%, (stems) and 0.1% (leaves) were obtained by hydrodistillation. Thirteen, sixteen and eighteen components, respectively, were identified by comparison of their mass spectra with those in the Wiley GC-MS Library data base. The major components of the flower and stem oils were 1-nonane (38.8% flowers; 33.5% stems), alpha-pinene (29.0% flowers; 14.8% stems) and germacrene D (15.6% flowers; 18.6% stems). However, in the leaf oil, germacrene D was observed at 50.7%, followed by beta-cedrene at 8.4%. The leaf essential oil showed a broad spectrum of antibacterial activity against the important human pathogenic Gram-positive and Gram-negative bacteria Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 19433), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Klebsiella pneumoniae (ATCC 25955) with MIC values ranging from 75 to 6000 ppm.

Composición química y actividad antibacteriana del aceite esencial de Ambrosia peruviana Willd. de los llanos venezolanos / Chemical composition and antibacterial activity of the essential oil of Ambrosia peruviana Willd. from Venezuelan plains

En Venezuela actualmente se están explorando nuevas fuentes de agentes antibacterianos de origen natural, debido al aumento de la resistencia bacteriana, entre ellos los aceites esenciales derivados de plantas. Por tal razón en el presente estudio se determinó la composición química del aceite esencial obtenido de las hojas de Ambrosia peruviana Willd recolectada en Guasdualito, Estado Apure, Venezuela. Los compuestos volátiles se aislaron por hidrodestilación en una trampa de Clevenger y posteriormente se realizó el análisis cualitativo-cuantitativo a través de cromatografía de gases acoplada a espectrometría de masas (GC/MS), en un equipo HP GC-MS System, modelo 5973, encontrando como compuestos mayoritarios al gamma-curcumeno (23,99%), seguido de ar-curcumeno (14,08%), acetato de bornilo (10,35%), camfor (5,03%) y epóxido de oximene (4,79%). La actividad antibacteriana del aceite esencial realizada por el método de difusión en agar con discos frente a Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Salmonella Typhi y Pseudomonas aeruginosa, mostró actividad contra S. aureus, E. faecalis, E. coli, y S. Typhi, con valores de CIM de 350-500 µg/ mL. Esta investigación es el primer reporte de actividad antibacteriana de A. peruviana.

In Venezuela, are currently exploring new sources of natural antibacterial agents, due to increased bacterial resistance, including essential oils derived from plants. For this reason in the present study we determined the chemical composition of essential oil obtained from leaves collected on Ambrosia peruviana Willd Guasdualito, Apure State, Venezuela. The volatile compounds were isolated by hydrodistillation in a Clevenger trap and then subjected to qualitative analysis and quantitative by gas chromatography-mass spectrometry (GC / MS) on an HP GC-MS System, model 5973, finding as the major compound gamma-curcumeno (23.99%) followed by curcumeno-ar (14.08%), bornyl acetate (10.35%), camphor (5.03%) and epoxide oximene (4.79%). The antibacterial activity of essential oil by the agar diffusion method with discs against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Salmonella typhi and Pseudomonas aeruginosashowed activity against S. aureus, E. faecalis, E. coli and S. Typhi, with MIC values of 350-500 micrograms/ mL. This research represents the first report of antibacterial activity of A. peruviana.

Composition of the essential oil of leaves and roots of Allium schoenoprasum L. (Alliaceae) / Composición del aceite esencial de hojas y raíces de Allium schoenoprasum L

Essential oil from leaves and roots of Allium schoenoprasum L. (Alliaceae) were analyzed by GC/MS. The oils extracted by hydrodistillation yielded 0.02 percent and 0.03 percent for leaves and roots, respectively. Five (99.12 percent leaves) and four (98.32 percent roots) components were identified being bis-(2-sulfhydryethyl)-disulfide (72.06 percent leaves, 56.47 percent roots) the major constituent on the two oil samples while 2,4,5-trithiahexane (5.45 percent leaves, 15.90 percent roots) and tris (methylthio)-methane (4.01 percent leaves, 12.81 percent roots) were detected in lower amounts.

Los aceites esenciales de hojas y raíces de Allium schoenoprasum L. (Alliaceae fueron analizados por CG/EM. La extracción por hidrodestilación mostró un rendimiento de 0.02 por ciento y 0.03 por ciento para las hojas y raíces, respectivamente. Cinco (99.12 por ciento hojas) y cuatro (98.32 por ciento raíces) compuestos fueron identificados siendo el bis-(2-sulfidietil)-disulfuro (72.06 por ciento hojas, 56.47 por ciento raíces) el compuesto mayoritario en los dos aceites mientras que 2,4,5-tritiahexano (5.45 por ciento hojas, 15.90 por ciento raíces) y tris (metilthio)-metano (4.01 por ciento hojas, 12.81 por ciento raíces) fueron observados en menores cantidades.