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Search Results: 1 - 10 of 468403 matches for " ALEJANDRO URZúA "
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SECONDARY METABOLITES IN THE EPICUTICLE OF HAPLOPAPPUS FOLIOSUS DC. (ASTERACEAE)
URZúA,ALEJANDRO;
Journal of the Chilean Chemical Society , 2004, DOI: 10.4067/S0717-97072004000200006
Abstract: from the ch2cl2 extract of the surface of haplopappus foliosus, monoterpenes, sesquiterpenes, flavonoids, coumarins, phenyl propanoids, n-alkanes and different miscellaneous compounds were identified. the complexity of the chemistry in terms of number of families and compounds makes attractive the use of this specie as a model to study variations in the cuticle chemistry, triggered by different ecological pressures. keywords: haplopappus foliosus; monoterpenes; sesquiterpenes; flavonoids; coumarins; phenyl propanoids, n-alkanes; miscellaneous compounds
MONOTERPENES AND SESQUITERPENES IN THE HEADSPACE VOLATILES FROM INTACT PLANTS OF PSEUDOGNAPHALIUM VIRA VIRA, P. HETEROTRICHIUM, P. CHEIRANTHIFOLIUM AND P. ROBUSTUM: THEIR INSECT REPELLENT FUNCTION
URZúA,ALEJANDRO;
Boletín de la Sociedad Chilena de Química , 2002, DOI: 10.4067/S0366-16442002000200005
Abstract: thirty-seven monoterpenes and sesquiterpenes have been identified in the headspace of four pseudognaphalium spp. the major compound identified was a-(z)-ocimene [1]: 87.0% in p. vira vira, 45.0% in p. heterotrichium, 41.0% in p. cheiranthifolium and 76.0% in p. robustum. other major components were germacrene d [2] (6.4%) in p. vira vira, b-phellandrene [3] (45.4% and 27.4%) in p. heterotrichium and p. cheiranthifolium, germacrene b [4](17.9%) in p. cheiranthifolium and (e)-3,7,11-trimethyl-1,6,10-dodecatriene-3-ol [5] (9.5%) in p. robustum. the insect repellent function of the mixture of volatile compounds is discussed
SECONDARY METABOLITES IN THE EPICUTICLE OF HAPLOPAPPUS FOLIOSUS DC. (ASTERACEAE)
ALEJANDRO URZúA
Journal of the Chilean Chemical Society , 2004,
Abstract: From the CH2Cl2 extract of the surface of Haplopappus foliosus, monoterpenes, sesquiterpenes, flavonoids, coumarins, phenyl propanoids, n-alkanes and different miscellaneous compounds were identified. The complexity of the chemistry in terms of number of families and compounds makes attractive the use of this specie as a model to study variations in the cuticle chemistry, triggered by different ecological pressures. Keywords: Haplopappus foliosus; Monoterpenes; Sesquiterpenes; Flavonoids; Coumarins; phenyl propanoids, n-Alkanes; miscellaneous compounds
MONOTERPENES AND SESQUITERPENES IN THE HEADSPACE VOLATILES FROM INTACT PLANTS OF PSEUDOGNAPHALIUM VIRA VIRA, P. HETEROTRICHIUM, P. CHEIRANTHIFOLIUM AND P. ROBUSTUM: THEIR INSECT REPELLENT FUNCTION
ALEJANDRO URZúA
Boletín de la Sociedad Chilena de Química , 2002,
Abstract: Thirty-seven monoterpenes and sesquiterpenes have been identified in the headspace of four Pseudognaphalium spp. The major compound identified was alpha-(z)-ocimene [1]: 87.0% in P. vira vira, 45.0% in P. heterotrichium, 41.0% in P. cheiranthifolium and 76.0% in P. robustum. Other major components were germacrene D [2] (6.4%) in P. vira vira, beta-phellandrene [3] (45.4% and 27.4%) in P. heterotrichium and P. cheiranthifolium, germacrene B [4](17.9%) in P. cheiranthifolium and (E)-3,7,11-trimethyl-1,6,10-dodecatriene-3-ol [5] (9.5%) in P. robustum. The insect repellent function of the mixture of volatile compounds is discussed Treinta y siete monoterpenos y sesquiterpenos han sido identificados en la mezcla de volátiles del "headspace" de cuatro especies de Pseudognaphalium. Uno de los compuestos mayoritarios que se identificó fue alfa-(z)-ocimeno [1], 87.0% en P. vira vira, 45.0% en P. heterotrichium, 41.0% en P. cheiranthifolium y 76.0% en P. robustum. Otros compuestos mayoritarios fueron germacreno D [2] (6.4%) en P. vira vira, beta-felandreno [3] (45.4 y 27.4%) en P. heterotrichium y P. cheiranthifolium, germacreno B [4] (17.9%) en P. cheiranthifolium y (E)-3,7,11-trimetil-1, 6, 10-dodecatrieno-3-ol [5] (9.5%) en P. robustum. Se discute el papel de la mezcla de volátiles como repelente de insectos
EPICUTICULAR COMPONENTS FROM PSEUDOGNAPHALIUM ROBUSTUM (ASTERACEAE): CHEMOSYSTEMATIC CONSIDERATIONS
URZúA,ALEJANDRO; MENDOZA,LEONORA;
Journal of the Chilean Chemical Society , 2008, DOI: 10.4067/S0717-97072008000100018
Abstract: surface compounds were obtained by a methylene chloride extraction of fresh aerial parts of pseudognaphalium robustum. the methylene chloride extract was fractionated by cc and the fractions were analyzed by gc-ms. since flavonoids and terpenes are present only in small amounts in the epicuticular exúdate of p. robustum, 80% of the surface compounds actually correspond to a complex mixture of saturated fatty acid esters, unsaturated fatty acid esters, alcohols, aldehydes, fatty acids, alkenes, triglycerides and monoglycerides. a minor hydrocarbon fraction of n-alkanes from c23 to c37 was also identified. on the contrary, in p. vira vira, p. cheiranthifolium, and p. heterotrichium, the epicuticular extracts contain from 70% to 80% of a mixture of diterpenoids and n-alkanes. these results show a remarkable distance between p. robustum and other species of the genus, which share the same ecosystem, when the whole pool of epicuticular compounds is taken into account. also, these considerable differences in chemical composition are in agreement with authors that consider pseudognaphalium as a heterogeneous taxonomic group
EPICUTICULAR COMPONENTS FROM PSEUDOGNAPHALIUM ROBUSTUM (ASTERACEAE): CHEMOSYSTEMATIC CONSIDERATIONS
ALEJANDRO URZúA,LEONORA MENDOZA
Journal of the Chilean Chemical Society , 2008,
Abstract: Surface compounds were obtained by a methylene chloride extraction of fresh aerial parts of Pseudognaphalium robustum. The methylene chloride extract was fractionated by CC and the fractions were analyzed by GC-MS. Since flavonoids and terpenes are present only in small amounts in the epicuticular exúdate of P. robustum, 80% of the surface compounds actually correspond to a complex mixture of saturated fatty acid esters, unsaturated fatty acid esters, alcohols, aldehydes, fatty acids, alkenes, triglycerides and monoglycerides. A minor hydrocarbon fraction of n-alkanes from C23 to C37 was also identified. On the contrary, in P. vira vira, P. cheiranthifolium, and P. heterotrichium, the epicuticular extracts contain from 70% to 80% of a mixture of diterpenoids and n-alkanes. These results show a remarkable distance between P. robustum and other species of the genus, which share the same ecosystem, when the whole pool of epicuticular compounds is taken into account. Also, these considerable differences in chemical composition are in agreement with authors that consider Pseudognaphalium as a heterogeneous taxonomic group
SEASONAL VARIATION OF THE FLAVONOIDS PINOCEMBRIN AND 3-O-METHYLGALANGIN, IN THE SURFACE COMPONENT MIXTURE (RESINOUS EXUDATES AND WAXY COATING) OF HELIOTROPIUM STENOPHYLLUM
MODAK,BRENDA; TORRES,RENé; URZúA,ALEJANDRO;
Journal of the Chilean Chemical Society , 2011, DOI: 10.4067/S0717-97072011000100002
Abstract: in this report we study the seasonal variation of the flavonoids pinocembrin and 3-o-methylgalangin in the surface component mixture (resinous exudate and waxy coating) of heliotropium stenophyllum. the quantitative analysis of the flavonoids was performed using high-performance liquid chromatography of samples collected monthly over a whole year. the results showed an increase in the spring and summer yield of surface components and a decrease during the winter. although the sum of pinocembrin and 3-o-methylgalangin did not follow a pattern related with hydric stress, uv radiation or high temperature during the year, a relationship between pinocembrin and 3-o-methylgalangin was found. on average during the months of september to august, excluding march, the amount of pinocembrin decreased wile the amount of 3-o-methylgalangin increased. the results suggest that the above compounds may play different ecophysiological functions during plant development and are consistent with the biosynthetic relationship between the two compounds.
IDENTIFICATION OF A NEW AROMATIC GERANYL DERIVATIVE IN THE RESINOUS EXUDATE OF HELIOTROPIUM FILIFOLIUM (BORAGINACEAE)
URZúA,ALEJANDRO; MODAK,BRENDA; TORRES,RENE;
Boletín de la Sociedad Chilena de Química , 2001, DOI: 10.4067/S0366-16442001000200011
Abstract: a new aromatic geranyl derivative was isolated from the resinous exudate of heliotropium filifolium. the structure was elucidated by high-resolution spectroscopic methods as filifolinyl senecionate. the compound has shown antibacterial activity against escherichia coli k-12. after irradiation of a solution of filifolinyl senecionate with uv at 366 nm, the antibacterial activity was enhanced by 100%
IDENTIFICATION OF A NEW AROMATIC GERANYL DERIVATIVE IN THE RESINOUS EXUDATE OF HELIOTROPIUM FILIFOLIUM (BORAGINACEAE)
ALEJANDRO URZúA,BRENDA MODAK,RENE TORRES
Boletín de la Sociedad Chilena de Química , 2001,
Abstract: A new aromatic geranyl derivative was isolated from the resinous exudate of Heliotropium filifolium. The structure was elucidated by high-resolution spectroscopic methods as filifolinyl senecionate. The compound has shown antibacterial activity against Escherichia coli K-12. After irradiation of a solution of filifolinyl senecionate with UV at 366 nm, the antibacterial activity was enhanced by 100% Del exudado resinoso de Heliotropium filifolium, se aisló un nuevo derivado aromático geranilado. Este compuesto se identificó por métodos espectrópicos de alta resolución como filifolinil senecionato. El compuesto mostró actividad antibacteriana contra Escherichia coli K-12. Esta actividad se vio incrementada en un 100% después de irradiar una solución de filifolinil senecionato con UV a 366 nm
SEASONAL VARIATION OF THE FLAVONOIDS PINOCEMBRIN AND 3-O-METHYLGALANGIN, IN THE SURFACE COMPONENT MIXTURE (RESINOUS EXUDATES AND WAXY COATING) OF HELIOTROPIUM STENOPHYLLUM
BRENDA MODAK,RENé TORRES,ALEJANDRO URZúA
Journal of the Chilean Chemical Society , 2011,
Abstract: In this report we study the seasonal variation of the flavonoids pinocembrin and 3-O-methylgalangin in the surface component mixture (resinous exudate and waxy coating) of Heliotropium stenophyllum. The quantitative analysis of the flavonoids was performed using high-performance liquid chromatography of samples collected monthly over a whole year. The results showed an increase in the spring and summer yield of surface components and a decrease during the winter. Although the sum of pinocembrin and 3-O-methylgalangin did not follow a pattern related with hydric stress, UV radiation or high temperature during the year, a relationship between pinocembrin and 3-O-methylgalangin was found. On average during the months of September to August, excluding March, the amount of pinocembrin decreased wile the amount of 3-O-methylgalangin increased. The results suggest that the above compounds may play different ecophysiological functions during plant development and are consistent with the biosynthetic relationship between the two compounds.
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