oscar crescente - Academia.edu (original) (raw)
Papers by oscar crescente
Planta Medica, Sep 1, 2002
The tagitinins isolated of Tithonia diversifolia (Hemsl.) A. Gray, Asteraceae, are the most studi... more The tagitinins isolated of Tithonia diversifolia (Hemsl.) A. Gray, Asteraceae, are the most studied sesquiterpene lactones due to their wide spectrum of pharmacologic activities, especially related with nuclear factor-kappa B inhibition. Nevertheless, detailed studies about the mechanism of action of its active compounds are still lacking. Neutrophils perform a fundamental role in the inflammatory response to several etiologic factors. However, the effect of tagitinins on human neutrophil is not yet clearly known. We investigated the role of tagitinin C (1), tagitinin F (2) and tagitinin A (3) in activation and survival of human neutrophils to establish possible effects in their mechanisms of inflammation. Human neutrophils were purified from the peripheral blood and cultivated with tagitinins C (1), F (2) and A (3) in the presence or not of Escherichia coli lipopolysaccharide. The enzymatic activity, apoptosis and secretion of cytokines rate were determined after 18 h. Lipopolysaccharide-induced myeloperoxidase activity of human neutrophils was significantly inhibited only by tagitinin F (2). Apoptosis of neutrophils was increased in the presence of tagitinin C (1), and it occurred independently of the presence of lipopolysaccharide or dexamethasone. Tagitinins C (1), F (2) and A (3) decrease lipopolysaccharide-induced interleukin-6, interleukin-8 and Tumor necrosis factor alpha production by human neutrophils. Together, these results indicate that tagitinins exhibit anti-inflammatory action on human neutrophils. However, tagitinin F (2) was the only sesquiterpene lactone that decreased secretion of inflammatory products by neutrophils without inducing neutrophil apoptosis.
DOAJ (DOAJ: Directory of Open Access Journals), Mar 1, 2021
Ciencia, 1999
The increasing interest for the medicinal properties in plants is what induced the present work a... more The increasing interest for the medicinal properties in plants is what induced the present work and was selected for the ethnobotanical information the species Espeletia schultzii Wedd. (Frailejón de Octubre), of the family Asteraceae, to accomplish an in vitro evaluation of its antibiotic and phototoxic activities. This species is used for the treatment of asthma in folk medicine in the Venezuelan Andes. A phytochemical evaluation was carried out which confirmed that the inflorescences extract contains kaurenic acids, it was isolated and identified benzophenone and two flavonoids, identified as quercetin and its 3-0-galactoside. These are the first flavonoids found in this species, and this is the first report of benzophenone in genus Espeletia. Three fractions obtained of the ethyl acetate extract, as well as the aqueous residual extract, were selected to accomplish an in vitro evaluation of their antibiotic and phototoxic activities. These activities were tested employing bacteria of clinical origin. Only one of the ethyl acetate fractions and the aqueous residual were found active against at least one bacterial strain. As far as we know, this study constitutes the first report on evaluation of the antibacterial activity of E. schultzii Wedd.
Potencial efecto fungicida de extractos vegetales en el desarrollo in vitro del hongo Colletotric... more Potencial efecto fungicida de extractos vegetales en el desarrollo in vitro del hongo Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. y de la antracnosis en frutos de mango Potential fungicidal effect of plant extracts on in vitro development of Colletotrichum gloeosporioides and on anthracnose of mango
Acta Microscopica, May 29, 2015
SABER, 1999
y procedimientos que permitan la utilización comercial de estos desechos, y evaluar su posible us... more y procedimientos que permitan la utilización comercial de estos desechos, y evaluar su posible uso en la elaboración de piensos para la alimentación de animales de corral. Los análisis realizados (proteínas (8,69 %), grasas (1 ,40 %), materia orgáníca (60,1 4 %) y minerales) revelan el uso potencial de estos desechos agrícolas en la elaboración de dietas para animales y como fertilizante orgáníco de numerosos cultivos.
resUmen La 5,4'-dihidroxi-3,7,8,3'-tetrametoxiflavona (ternatina, 1) fue aislada de Eglet... more resUmen La 5,4'-dihidroxi-3,7,8,3'-tetrametoxiflavona (ternatina, 1) fue aislada de Egletes prostrata (Plantae: Asteracea) y la estructura fue elucidada por interpretación de datos espectroscópicos y por comparación con datos reportados para estructuras modelos. Esta flavona exhibió un fuerte efecto antioxidante determinado mediante inhibición de la oxidación del luminol inducida por H 2 O 2. El grado de inhibición de la oxidación del luminol determinado fue de 85 a 41% a las concentraciones de 53,5 y 1,07 μM de ternatina, respectivamente, es considerado fuerte. Palabras clave: Ternatina, efecto antioxidante, citotoxicidad, Egletes postrata. ABstrAct The 5,4'-dihydroxy-3,7,8,3'-tetramethoxyflavone (ternatin, 1) was isolated from Egletes postrata (Plantae: Asteracea), and the structure was elucidated by interpretation of spectroscopic data and by comparison with reports of models structure in the literature. The flavone exhibits strong antioxidant properties as determ...
Revista de biología tropical, 2000
The dose dependent antiproliferative effect of an alkaloidal substance extracted from the sponge ... more The dose dependent antiproliferative effect of an alkaloidal substance extracted from the sponge Amphimedon viridis was tested on Leishmania mexicana promastigotes. Sponges were collected in Isla Larga, Venezuela (10 degrees 20' 20" - 10 degrees 24" N, 64 degrees 19' - 64 degrees 22' W), cut and dipped in methanol for vacum filtering extraction every 24 hr. The aqueous extract was separated by chromatography over silica gel. The parasites were from the Venezuelan NR strain. Their growth rate was reduced by 50 % with a dose of 10 microg/ml in 48 hr, whilst concentrations of 30 and 40 microg/ml induce leishmanicidal action after 110 and 20 min, respectively. Lysis is preceded by an immediate increase in cellular volume associated with progressive damage of cellular content and the destruction of organelles. These findings suggest that one important factor associated with the antiproliferative effect of this alkaloidal substance on L. mexicana promastigotes is the...
El aceite esencial de Wedelia calycina L.C. Rich fue extraido para evaluar su composicion quimica... more El aceite esencial de Wedelia calycina L.C. Rich fue extraido para evaluar su composicion quimica, actividad antibacteriana y antifungica. El aceite esencial fue obtenido por destilacion de arrastre por vapor de las hojas y arrojo un rendimiento del 0,025%. Este fue analizado por Cromatografia de Gases/Espectrometria de Masas (CG/EM), ademas de compararlo con los indices de retencion de compuestos modelos. Fueron identificados 44 compuestos, entre los que estan en mayor proporcion: germacreno D (8,83%), 3,3,7,7-tetrametil-5-(2-metil-1-propenil)-triciclo[4.1.0.0(2,4)] heptano (8,66%), β-sesquifelandreno (7,87%), oxido de cariofileno (5,10%) y (+)-octahidro-4,8,8,9-tetrametil-1,4-metanoazulen-7(1H)-ona (4,65%). Predominan los grupos de compuestos sesquiterpenicos hidrocarbonados (44,83%) y oxigenados (26,90%), seguido por monoterpenos (15,79%), y el 12,48% restante corresponde a compuestos alifaticos de baja masa molecular. El aceite esencial mostro actividad antibacteriana moderada c...
African Journal of Biotechnology, 2011
During our screening program for new agrochemicals from Chinese medicinal herbs, essential oil of... more During our screening program for new agrochemicals from Chinese medicinal herbs, essential oil of Caryopteris incana aerial parts was found to possess strong insecticidal activities against the maize weevil, Sitophilus zeamais. A total of 37 components of the essential oil were identified by GC and GC/MS. Estragole (24.8%) and linalool (14.0%) are the two main components of the essential oil followed by 1,8-cineol (5.2%) and δ-guaiene (4.1%). The essential oil possesses strong fumigant toxicity against S. zeamais adults with an LC 50 value of 10.05 mg/L air. The essential oil of C. incana also showed contact toxicity against S. zeamais adults with an LD 50 value of 122.65 µg/adult. The essential oil C. incana may have potential to be developed as a new natural fumigant/insecticide for the control of stored product insects.
Leaves, stems, and fl owers of Ipomoea quamoclit were collected in San Juan de Macarapana, Sucre ... more Leaves, stems, and fl owers of Ipomoea quamoclit were collected in San Juan de Macarapana, Sucre municipality of the state of Sucre, with the purpose of drawing their hexanic and methanolic extracts. The percent quantity of the latter resulted more abundant than that of the former. Each extract was phytochemically analyzed and tested for antibacterial activity at three different concentrations. Overall, positive results were obtained for alkaloids, fl avonoids, and polyphenols among the six extracts, the methanolic extract from the stem being the only one having a positive result for saponins. The hexanic extract from the stems inhibited the bacterial growth of Salmonella enteritidis, Escherichia coli, Bacillus cereus, and Staphlococcus aureus, whereas their methanolic extract only affected the growth of E. coli. The hexanic extract from the leaves inhibited the growth of B. cereus, whereas their methanolic extract was unable to inhibit the growth of any bacterium. The hexanic extract from the fl owers only arrested the growth of S. aureus, their methanolic one inhibiting instead the expansion of S. enteritidis, S. aureus, and B. cereus. These results cast Ipomoea quamoclit as a likely source of substances capable of counteracting the pathogenic effects of the bacteria assayed.
FACSALUD-UNEMI, 2019
Ulomoides dermestoides (Coleoptera: Tenebrionidae) (Fairm), conocidos como “gorgojos chinos”, han... more Ulomoides dermestoides (Coleoptera: Tenebrionidae) (Fairm), conocidos como “gorgojos chinos”, han sido usados con éxito como medicina en terapias no convencionales. Los metabolitos de U. dermestoides fueron extraídos tanto a partir de grupos de individuos vivos (UD1 hexano, acetona e isopropanol), como de individuos previamente refrigerados por 72h (UD2 hexano, diclorometano, acetona y metanol). La composición de estos extractos fue determinada mediante Cromatografia de Gases-Espectrometría de Masas (CG-EM). El análisis químico preliminar mostró ausencia de saponinas en todos los extractos y presencia de esteroles y triterpenos en el extracto hexánico de ambas muestras. La prueba de alcaloides resultó positiva para UD2 diclorometano, acetona y metanol, y la de polifenoles para UD1 en isopropanol y UD2 acetona. También, resultaron positivas la prueba para flavonoides en UD1 isopropílico y UD2 hexánico, cumarinas en todos los extractos UD2 y glicósidos cianogénicos en UD2 acetona. Los...
RESUMEN A partir de extractos metanolicos de flores de Cordia alba (Plantae: Boraginaceae) se ais... more RESUMEN A partir de extractos metanolicos de flores de Cordia alba (Plantae: Boraginaceae) se aislo la alantoina en forma cristalina. Esta fue caracterizada estructuralmente mediante analisis de resonancia magnetica nuclear uni y bidimensional, difraccion de rayos X de cristal unico y espectrometria de masas mediante ionizacion por electronebulizacion. La existencia de alantoina en C. alba justifica el uso etnobotanico de especies de Cordia como cicatrizante en la medicina folclorica. Ademas, esto demuestra que la alantoina es un posible marcador quimiotaxonomico en este genero vegetal. Palabras clave : Cordianina, marcador quimiotaxonomico, estructura cristalina. ABSTRACT From methanolic extracts of flowers of Cordia alba (Plantae: Boraginaceae), allantoin was isolated in crystalline form. It was structurally characterized by analysis of uni- and two-dimensional nuclear magnetic resonance, single crystal X-ray diffraction and mass spectrometry using electrospray ionization. The exi...
RESUMEN: El presente estudio fue realizado para identificar por Cromatografia de Gases/Espectrome... more RESUMEN: El presente estudio fue realizado para identificar por Cromatografia de Gases/Espectrometria de Masas (CG/EM) los compuestos mayoritarios presentes en las fracciones dos, tres y cuatro del extracto hexanico del alga roja Gelidium serrulatum, debido a la actividad antibacteriana moderada que presento. Los compuestos mayoritarios identificados fueron hidrocarburos saturados e insaturados, alcoholes, fenoles, lactonas, cetonas, acidos grasos y esteroles. Se identificaron los acidos grasos miristico, caproico, laurico y palmitico y los esteroles colest-5-en-3β-ol, colest-4-en-3-ona, 4,6-colestadien-3-ona y colestan-3,6-diona. En las algas marinas, quizas, estos compuestos funcionen como antimicrobianos, antiincrustantes y probablemente, sean responsables de las actividades biologicas presentadas por G. serrulatum.Palabras clave: Algas, identificacion, acidos grasos, esterolesABSTRACT: The present study was performed to identify by Gas Cromatography/Mass Spectrometry (GC/MS) the...
El extracto en diclorometano de las hojas de Chromo/aena odorata (L.) K. et R. Compositae, tratad... more El extracto en diclorometano de las hojas de Chromo/aena odorata (L.) K. et R. Compositae, tratado para lactonas sesquiterpenicas y posteriormente fraccionado a traves de cromatografia columna flash sobre silica gel, de exclusion molecular y TLC, arrojo como resultado la separacion de 6-hidroxi-4' ,5, 7 -trimetoxi flavanona. La identificacion de la flavanona aislada se realizo combinando tecnicas de analisis espectrales de RMN ('H y 13C), UV /vis., EM e IR, y por comparacion con resultados de estructuras modelos. Una busqueda bibliografica no proporciono dato alguno sobre este compuesto por lo que se presume que este es el primer reporte para esta flavanona. Por otra parte, la flavanona aislada posee accion antibacterial contra Staphylococcus aureus y Bacillus cereus, mostrando una CMI de 179,2-238,3 Jlg/ml contra ambos microorganismos. ASBTRACT The dichloromethane leaf extract of Chromolaena odorata (L.) K. et R. Compositae, treated with lead acetate as for sesquiterpene la...
Boletin De Investigaciones Marinas Y Costeras Invemar, Jun 1, 2011
Planta Medica, Sep 1, 2002
The tagitinins isolated of Tithonia diversifolia (Hemsl.) A. Gray, Asteraceae, are the most studi... more The tagitinins isolated of Tithonia diversifolia (Hemsl.) A. Gray, Asteraceae, are the most studied sesquiterpene lactones due to their wide spectrum of pharmacologic activities, especially related with nuclear factor-kappa B inhibition. Nevertheless, detailed studies about the mechanism of action of its active compounds are still lacking. Neutrophils perform a fundamental role in the inflammatory response to several etiologic factors. However, the effect of tagitinins on human neutrophil is not yet clearly known. We investigated the role of tagitinin C (1), tagitinin F (2) and tagitinin A (3) in activation and survival of human neutrophils to establish possible effects in their mechanisms of inflammation. Human neutrophils were purified from the peripheral blood and cultivated with tagitinins C (1), F (2) and A (3) in the presence or not of Escherichia coli lipopolysaccharide. The enzymatic activity, apoptosis and secretion of cytokines rate were determined after 18 h. Lipopolysaccharide-induced myeloperoxidase activity of human neutrophils was significantly inhibited only by tagitinin F (2). Apoptosis of neutrophils was increased in the presence of tagitinin C (1), and it occurred independently of the presence of lipopolysaccharide or dexamethasone. Tagitinins C (1), F (2) and A (3) decrease lipopolysaccharide-induced interleukin-6, interleukin-8 and Tumor necrosis factor alpha production by human neutrophils. Together, these results indicate that tagitinins exhibit anti-inflammatory action on human neutrophils. However, tagitinin F (2) was the only sesquiterpene lactone that decreased secretion of inflammatory products by neutrophils without inducing neutrophil apoptosis.
DOAJ (DOAJ: Directory of Open Access Journals), Mar 1, 2021
Ciencia, 1999
The increasing interest for the medicinal properties in plants is what induced the present work a... more The increasing interest for the medicinal properties in plants is what induced the present work and was selected for the ethnobotanical information the species Espeletia schultzii Wedd. (Frailejón de Octubre), of the family Asteraceae, to accomplish an in vitro evaluation of its antibiotic and phototoxic activities. This species is used for the treatment of asthma in folk medicine in the Venezuelan Andes. A phytochemical evaluation was carried out which confirmed that the inflorescences extract contains kaurenic acids, it was isolated and identified benzophenone and two flavonoids, identified as quercetin and its 3-0-galactoside. These are the first flavonoids found in this species, and this is the first report of benzophenone in genus Espeletia. Three fractions obtained of the ethyl acetate extract, as well as the aqueous residual extract, were selected to accomplish an in vitro evaluation of their antibiotic and phototoxic activities. These activities were tested employing bacteria of clinical origin. Only one of the ethyl acetate fractions and the aqueous residual were found active against at least one bacterial strain. As far as we know, this study constitutes the first report on evaluation of the antibacterial activity of E. schultzii Wedd.
Potencial efecto fungicida de extractos vegetales en el desarrollo in vitro del hongo Colletotric... more Potencial efecto fungicida de extractos vegetales en el desarrollo in vitro del hongo Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. y de la antracnosis en frutos de mango Potential fungicidal effect of plant extracts on in vitro development of Colletotrichum gloeosporioides and on anthracnose of mango
Acta Microscopica, May 29, 2015
SABER, 1999
y procedimientos que permitan la utilización comercial de estos desechos, y evaluar su posible us... more y procedimientos que permitan la utilización comercial de estos desechos, y evaluar su posible uso en la elaboración de piensos para la alimentación de animales de corral. Los análisis realizados (proteínas (8,69 %), grasas (1 ,40 %), materia orgáníca (60,1 4 %) y minerales) revelan el uso potencial de estos desechos agrícolas en la elaboración de dietas para animales y como fertilizante orgáníco de numerosos cultivos.
resUmen La 5,4'-dihidroxi-3,7,8,3'-tetrametoxiflavona (ternatina, 1) fue aislada de Eglet... more resUmen La 5,4'-dihidroxi-3,7,8,3'-tetrametoxiflavona (ternatina, 1) fue aislada de Egletes prostrata (Plantae: Asteracea) y la estructura fue elucidada por interpretación de datos espectroscópicos y por comparación con datos reportados para estructuras modelos. Esta flavona exhibió un fuerte efecto antioxidante determinado mediante inhibición de la oxidación del luminol inducida por H 2 O 2. El grado de inhibición de la oxidación del luminol determinado fue de 85 a 41% a las concentraciones de 53,5 y 1,07 μM de ternatina, respectivamente, es considerado fuerte. Palabras clave: Ternatina, efecto antioxidante, citotoxicidad, Egletes postrata. ABstrAct The 5,4'-dihydroxy-3,7,8,3'-tetramethoxyflavone (ternatin, 1) was isolated from Egletes postrata (Plantae: Asteracea), and the structure was elucidated by interpretation of spectroscopic data and by comparison with reports of models structure in the literature. The flavone exhibits strong antioxidant properties as determ...
Revista de biología tropical, 2000
The dose dependent antiproliferative effect of an alkaloidal substance extracted from the sponge ... more The dose dependent antiproliferative effect of an alkaloidal substance extracted from the sponge Amphimedon viridis was tested on Leishmania mexicana promastigotes. Sponges were collected in Isla Larga, Venezuela (10 degrees 20' 20" - 10 degrees 24" N, 64 degrees 19' - 64 degrees 22' W), cut and dipped in methanol for vacum filtering extraction every 24 hr. The aqueous extract was separated by chromatography over silica gel. The parasites were from the Venezuelan NR strain. Their growth rate was reduced by 50 % with a dose of 10 microg/ml in 48 hr, whilst concentrations of 30 and 40 microg/ml induce leishmanicidal action after 110 and 20 min, respectively. Lysis is preceded by an immediate increase in cellular volume associated with progressive damage of cellular content and the destruction of organelles. These findings suggest that one important factor associated with the antiproliferative effect of this alkaloidal substance on L. mexicana promastigotes is the...
El aceite esencial de Wedelia calycina L.C. Rich fue extraido para evaluar su composicion quimica... more El aceite esencial de Wedelia calycina L.C. Rich fue extraido para evaluar su composicion quimica, actividad antibacteriana y antifungica. El aceite esencial fue obtenido por destilacion de arrastre por vapor de las hojas y arrojo un rendimiento del 0,025%. Este fue analizado por Cromatografia de Gases/Espectrometria de Masas (CG/EM), ademas de compararlo con los indices de retencion de compuestos modelos. Fueron identificados 44 compuestos, entre los que estan en mayor proporcion: germacreno D (8,83%), 3,3,7,7-tetrametil-5-(2-metil-1-propenil)-triciclo[4.1.0.0(2,4)] heptano (8,66%), β-sesquifelandreno (7,87%), oxido de cariofileno (5,10%) y (+)-octahidro-4,8,8,9-tetrametil-1,4-metanoazulen-7(1H)-ona (4,65%). Predominan los grupos de compuestos sesquiterpenicos hidrocarbonados (44,83%) y oxigenados (26,90%), seguido por monoterpenos (15,79%), y el 12,48% restante corresponde a compuestos alifaticos de baja masa molecular. El aceite esencial mostro actividad antibacteriana moderada c...
African Journal of Biotechnology, 2011
During our screening program for new agrochemicals from Chinese medicinal herbs, essential oil of... more During our screening program for new agrochemicals from Chinese medicinal herbs, essential oil of Caryopteris incana aerial parts was found to possess strong insecticidal activities against the maize weevil, Sitophilus zeamais. A total of 37 components of the essential oil were identified by GC and GC/MS. Estragole (24.8%) and linalool (14.0%) are the two main components of the essential oil followed by 1,8-cineol (5.2%) and δ-guaiene (4.1%). The essential oil possesses strong fumigant toxicity against S. zeamais adults with an LC 50 value of 10.05 mg/L air. The essential oil of C. incana also showed contact toxicity against S. zeamais adults with an LD 50 value of 122.65 µg/adult. The essential oil C. incana may have potential to be developed as a new natural fumigant/insecticide for the control of stored product insects.
Leaves, stems, and fl owers of Ipomoea quamoclit were collected in San Juan de Macarapana, Sucre ... more Leaves, stems, and fl owers of Ipomoea quamoclit were collected in San Juan de Macarapana, Sucre municipality of the state of Sucre, with the purpose of drawing their hexanic and methanolic extracts. The percent quantity of the latter resulted more abundant than that of the former. Each extract was phytochemically analyzed and tested for antibacterial activity at three different concentrations. Overall, positive results were obtained for alkaloids, fl avonoids, and polyphenols among the six extracts, the methanolic extract from the stem being the only one having a positive result for saponins. The hexanic extract from the stems inhibited the bacterial growth of Salmonella enteritidis, Escherichia coli, Bacillus cereus, and Staphlococcus aureus, whereas their methanolic extract only affected the growth of E. coli. The hexanic extract from the leaves inhibited the growth of B. cereus, whereas their methanolic extract was unable to inhibit the growth of any bacterium. The hexanic extract from the fl owers only arrested the growth of S. aureus, their methanolic one inhibiting instead the expansion of S. enteritidis, S. aureus, and B. cereus. These results cast Ipomoea quamoclit as a likely source of substances capable of counteracting the pathogenic effects of the bacteria assayed.
FACSALUD-UNEMI, 2019
Ulomoides dermestoides (Coleoptera: Tenebrionidae) (Fairm), conocidos como “gorgojos chinos”, han... more Ulomoides dermestoides (Coleoptera: Tenebrionidae) (Fairm), conocidos como “gorgojos chinos”, han sido usados con éxito como medicina en terapias no convencionales. Los metabolitos de U. dermestoides fueron extraídos tanto a partir de grupos de individuos vivos (UD1 hexano, acetona e isopropanol), como de individuos previamente refrigerados por 72h (UD2 hexano, diclorometano, acetona y metanol). La composición de estos extractos fue determinada mediante Cromatografia de Gases-Espectrometría de Masas (CG-EM). El análisis químico preliminar mostró ausencia de saponinas en todos los extractos y presencia de esteroles y triterpenos en el extracto hexánico de ambas muestras. La prueba de alcaloides resultó positiva para UD2 diclorometano, acetona y metanol, y la de polifenoles para UD1 en isopropanol y UD2 acetona. También, resultaron positivas la prueba para flavonoides en UD1 isopropílico y UD2 hexánico, cumarinas en todos los extractos UD2 y glicósidos cianogénicos en UD2 acetona. Los...
RESUMEN A partir de extractos metanolicos de flores de Cordia alba (Plantae: Boraginaceae) se ais... more RESUMEN A partir de extractos metanolicos de flores de Cordia alba (Plantae: Boraginaceae) se aislo la alantoina en forma cristalina. Esta fue caracterizada estructuralmente mediante analisis de resonancia magnetica nuclear uni y bidimensional, difraccion de rayos X de cristal unico y espectrometria de masas mediante ionizacion por electronebulizacion. La existencia de alantoina en C. alba justifica el uso etnobotanico de especies de Cordia como cicatrizante en la medicina folclorica. Ademas, esto demuestra que la alantoina es un posible marcador quimiotaxonomico en este genero vegetal. Palabras clave : Cordianina, marcador quimiotaxonomico, estructura cristalina. ABSTRACT From methanolic extracts of flowers of Cordia alba (Plantae: Boraginaceae), allantoin was isolated in crystalline form. It was structurally characterized by analysis of uni- and two-dimensional nuclear magnetic resonance, single crystal X-ray diffraction and mass spectrometry using electrospray ionization. The exi...
RESUMEN: El presente estudio fue realizado para identificar por Cromatografia de Gases/Espectrome... more RESUMEN: El presente estudio fue realizado para identificar por Cromatografia de Gases/Espectrometria de Masas (CG/EM) los compuestos mayoritarios presentes en las fracciones dos, tres y cuatro del extracto hexanico del alga roja Gelidium serrulatum, debido a la actividad antibacteriana moderada que presento. Los compuestos mayoritarios identificados fueron hidrocarburos saturados e insaturados, alcoholes, fenoles, lactonas, cetonas, acidos grasos y esteroles. Se identificaron los acidos grasos miristico, caproico, laurico y palmitico y los esteroles colest-5-en-3β-ol, colest-4-en-3-ona, 4,6-colestadien-3-ona y colestan-3,6-diona. En las algas marinas, quizas, estos compuestos funcionen como antimicrobianos, antiincrustantes y probablemente, sean responsables de las actividades biologicas presentadas por G. serrulatum.Palabras clave: Algas, identificacion, acidos grasos, esterolesABSTRACT: The present study was performed to identify by Gas Cromatography/Mass Spectrometry (GC/MS) the...
El extracto en diclorometano de las hojas de Chromo/aena odorata (L.) K. et R. Compositae, tratad... more El extracto en diclorometano de las hojas de Chromo/aena odorata (L.) K. et R. Compositae, tratado para lactonas sesquiterpenicas y posteriormente fraccionado a traves de cromatografia columna flash sobre silica gel, de exclusion molecular y TLC, arrojo como resultado la separacion de 6-hidroxi-4' ,5, 7 -trimetoxi flavanona. La identificacion de la flavanona aislada se realizo combinando tecnicas de analisis espectrales de RMN ('H y 13C), UV /vis., EM e IR, y por comparacion con resultados de estructuras modelos. Una busqueda bibliografica no proporciono dato alguno sobre este compuesto por lo que se presume que este es el primer reporte para esta flavanona. Por otra parte, la flavanona aislada posee accion antibacterial contra Staphylococcus aureus y Bacillus cereus, mostrando una CMI de 179,2-238,3 Jlg/ml contra ambos microorganismos. ASBTRACT The dichloromethane leaf extract of Chromolaena odorata (L.) K. et R. Compositae, treated with lead acetate as for sesquiterpene la...
Boletin De Investigaciones Marinas Y Costeras Invemar, Jun 1, 2011