A Phytochemical Analysis of Espeletia nana Cuatrec. a Midget Espeletiinae from Paramo Ortiz, Venezuela

Espeletia nana Cuatrec is a resinous plant, member of the Espeletiinae Subtribe. It is a small size frailejón, 25cm high, found at Páramo Ortiz, Trujillo State, Venezuela. Leaves and roots were separately extracted with a 3:1 mixture of hexane-diethyl ether. Aliquotes of the acidic fractions were methylated and inspected by GC-MS. It was found that the resin from the leaves contained kaurenic acid (1a, 34.6%), grandiflorenic acid (2a, 40.1%), 15-ent-acetoxy-kaur-16-en-19-oic acid (3a, 8%), and 15-hidroxy- ent-kaur-16-en-19-oic acid (3a, 13%). The roots acid fraction contained 38% 1a, 39,6% 2b, 8.5% 3a, and 13.9% 4a. The GC-MS analysis of the leaves neutral fraction yielded 43% kaurenal (5), 3% kaurenol (6), 13% ruilopeziol (7a), 7% epi-ruilopeziol, 25% of nonacontane and 8% of entriacontane. On the other hand the roots resin contained 88%, 5.7% of 6, 2.5% 7a, 1.0% 7b, but only 1.5% of waxes. The bulk extracts were submitted to flash chromatography, leading to the isolation of pure kaurenes which were identified by direct comparison with authentic samples

Caracterización química y actividad antimicrobiana del aceite esencial de las hojas de Libanothamnus neriifolius (Asteraceae)

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.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

Rhodium catalyzed hydroformylation of kaurane derivatives: A route to new diterpenes with potential bioactivity

Kaurenic and grandiflorenic acids are naturally occurring diterpenes whose biological activity has been described. Both acids contain an exocyclic methylenic double bond that allows further functionalization on their structure. In an attempt to expand the number of derivatives of these two natural products, we have undertaken a study on the hydroformylation of the methyl esters of the two acids and the trimethylsilyl ether of kaurenol. These substrates have been hydroformylated by using unmodified Rh catalysts, as well as Rh/PPh3 and Rh/tris-(o-t-butylphenyl)phosphite catalytic systems at 100 °C and 20 bar of CO/H2 (1:1). For the three substrates, the two Rh catalysts modified with P-donor ligands, produced high conversions and chemo- and regioselectivities in the diastereoisomeric pair of linear aldehydes. In all cases, the stereoselectivity observed is strongly dependent of the system used, being the most diastereoselective the least hindered unmodified Rh/CO catalyst. A correlation between the higher diastereoselectivity and the faster [beta]-elimination of the metal-alkyl intermediate observed in the unmodified system is discussed.http://www.sciencedirect.com/science/article/B6TF5-4RVMXFD-3/1/d27e671ad9e0b7fc325dfd0bdf413c7

Información Investigador: Usubillaga del Hierro, Alfredo Nicolás

Resumen Curricular Nació en Tumaco, Colombia en Noviembre 1931.Graduado como Ing. Químico en la Escuela Politécnica Nacional de Quito, Ecuador, en 1957. Master of Science, University of Illinois, 1959, PhD. University of Illinois, enero 1962. Ingresó a la ULA en Febrero 1962 como profesor contratado en la Facultad de Farmacia. Pasó a profesor ordinario en Mayo 1965 como Profesor agregado, Titular desde Mayo 1973.Director del Instituto de Investigaciones de la Facultad de Farmacia desde 01-04-79 hasta 30-9-87. Profesor de Físico-Química y Análisis Instrumental en Bioanálisis, Farmacia e Ingeniería Química. Fundador del Postgrado de Química de Medicamentos y su Coordinador desde 1981 hasta 1987. Jubilado desde sept. 1987 pero ha continuado activo en docencia de postgrado e Investigación hasta el presente. Acreditado como miembro del Programa de Promoción del Investigador, PPI II desde 1990, promovido en 1996 a PPI III y en 2004 promovido a PPI IV. Tutor de 3 tesinas de pregrado, 14 Trabajos de Grado de Maestría y 5 tesis doctorales. Ha realizado105 publicaciones en revistas nacionales arbitradas e internacionales. Ha descubierto 8 nuevos alcaloides esteroidales, 5 nuevas lactonas esteroidales, nuevos derivados del kaureno. Estudia la actividad citotóxica del ácido kaurénico y de sus ésteres azucarados, así como actividad antiplamodium de algunos derivados del kaureno obtenidos mediante síntesis. Medalla al mejor egresado, Escuela Politécnica 1956. Medalla Fray Juan Ramos de Lora, 1985, Bicentenario de la ULA. Premio regional de Ciencias Naturales y Exactas 1998 (FUNDACITE). Orden Tulio Febres Cordero Segunda Clase otorgado por la Asamblea Legislativa del Estado Mérida, 16-9-99.Doctorado1040IV - 2004; III - 2000155 - 2005; 186 - 2003; 82 - 2001Química medicinal, Química de productos naturales. Alcaloides esteroidales, Aceites esenciales, Diterpenoides, Síntesis y semisíntesis de sustancias con posible acción medicamentosa y surfactantes biocompatibles.Agosto de 2006Ingeniero Químico+58 274 2403559Facultad de Farmacia y Bioaná[email protected], [email protected]

Composition of the essential oil from a hybrid frailejon between Espeletia schultzii and Coespeletia moritziana (Espeletiinae)

El aceite esencial de una especie híbrida entre Espeletia schultzii y Coespeletia moritziana, dos especies de frailejón (Espeletiinae) que crecen en el páramo Pico El Águila, se analizó mediante cromatografía de gases (FID) y cromatografía de gases - masas. Se logró identificar 21 compuestos en el aceite obtenido de las hojas que representan un 94,3 % y 18 compuestos en el aceite proveniente de los tallos florales que constituyen el 93,5%. Tanto en el aceite de las hojas como en el de los tallos florales, el componente más abundante fue el α-pineno (30,4% y 33,4%), otros componentes importantes fueron el α-felandreno (21,4% y 14,4%), p-cimeno (9,7% y 11,0%) y el β-pineno (9,0% y 10,9%). Los monoterpenos constituyeron el 84,4% del aceite de las hojas y el 80,0% del de los tallos florales. El porcentaje del aceite esencial de la especie híbrida se encontró para todos los componentes en un valor intermedio de los valores observados en las especies [email protected], [email protected] essential oil of a hybrid between Espeletia schultzii and Coespeletia moritziana, two species of frailejon (Espeletiinae) that grow at paramo Pico El Aguila, was analyzed by gas chromatography (FID) and GC-MS. It was possible to identify 21 compounds in the oil from the leaves, which made up 94.3% of the oil and 18 compounds in the oil from the flowering stems which made up 93.5% of the oil. The most abundant constituent in the oil from the leaves was α-pinene (30.4%). In the flowering stems α-pinene was also the most abundant compound (33.4%). Other abundant components were α-phellandrene (21.4% and 14.4%), p-cymene (9.7% and 11.0%), and β-pinene (9.0% and 10.9%). Monoterpenes were 84.4% (leaves) and 80.0% (flowering stems) of the hybrid´s oil. The percentage composition of the different constituents of the hybrid´s oil was found to be the mean value of the percentages reported for those compounds in the oils of the parental species

Allylic oxidation of ent-Kaurenic acid, ent-Kaurenic acid Methyl Ester and ent-Kaurenol

The allylic oxidation of ent-kaurenic acid, ent-kaurenic acid methyl ester, and ent-kaurenol with SeO2/H2O2 is presented. The reaction was run in dioxan solution at room temperature stirring for 4 hours. About 0.3 mmol of substrate was treated with 1.2 mmol of SeO2 and 4.1 mmol of H2O2. Treatment of ent-kaurenic acid afforded 56% of ent-15α- hydroxy-kaur-16-en-19-oic acid (2a). Treatment of ent-kaurenic acid methyl ester afforded two products: ent-15α-hydroxy-kaur-16-en-19-oic acid methyl ester (2b, 34% yield) and ent-15α,16α-epoxi-17-hydroxy- kauran-19-oic acid methyl ester (3a, 59% yield). In a similar fashion treatment of ent-kaurenol rendered two products: ent-15α,17- dihydroxy-kaur-16-ene (2c, 56.7% yield) and ent-15α,16α-epoxi-17,19- dihydroxy-kaurane (3b, 34% yield). Additional experiments using twice as much or half as much H2O2 relative to the amount of SeO2 did not modify significantly the product ratio neither the yield