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Search Results: 1 - 10 of 331241 matches for " Hermán Vélez Castro "
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Estudio químico en especies cubanas del género Annona II: Annona sclerophylla Safford
Sandoval López,Daisy; Payo Hill,Armando; Vélez Castro,Hermán;
Revista Cubana de Farmacia , 2002,
Abstract: this paper presents the results of the study of the alkaloid contents in leaves and stems of the cuban endemic species called annona sclerophylla that has modest antimicrobial effects. for the extraction and purification of such metabolites, organic solvents and chromatographic methods of separation by columns are used. spectroscopic techniques like uv, ir, mass and nmr1h and 13c as well as the measurement of physical constants allowed identifying alkaloids isocorypalmine and liriodenine, and compounds (-)-kau-16-en-19-oico and (-)-kauran-16μ-o1.
Alcaloides en la especie cubana Croton micradenus Urb
Payo Hill,Armando; Sandoval López,Daisy; Vélez Castro,Hermán; Oquendo Suárez,Marledis;
Revista Cubana de Farmacia , 2001,
Abstract: the study of the content of alkaloids in the leaves and stems of the croton micradenus urb cuban endemic species, which is potentially medicinal, was conducted. organic solvents and chromatographic methods of separation by column and plate were used for the extraction and purification of these metabolites. 4 of the 6 isolated alkaloids, 3 of them morphinandienones: ocobotrine, sinoacutine and 8,14-dihydrosalutaridine and an aporphine (isobol-dine) were characterized by spectroscopic methods of uv, ir, mass and nmr 1h and 13c, as well as by the measurement of their physical constants.
Determinación cuantitativa por electroforesis capilar de zona de mangiferina en tabletas VIMANG? 300 mg
Curiel Hernández,Harold; Vélez Castro,Hermán; Lora García,Janet;
Revista Cubana de Farmacia , 2011,
Abstract: mangiferin was selected as marker in the quality control of active principle vimang? and its formulations, which have been used as nutritional supplement, cosmetic, and phytomedication. this paper was aimed at validating the capillary electrophoresis method for the quantitative analysis of mangiferin in the pharmaceutical formulation 300 mg vimang? tablets. the specificity, linearity, accuracy and precision were assessed. the results showed the method specificity owing to lack of interference by the excipients or their degradation products. linearity showed a correlation coefficient of 0.9979 in the studied concentration range. the variation coefficients for repeatability and intermediate precision were less than 2 %. accuracy reached a recovery rate of 100.20 % that is not statistically different from 100 %. it may be concluded that the validated method is specific, linear, precise and accurate and could be an advantageous alternative to the high resolution liquid chromatography method used at the lab setting.
Determinación cuantitativa por electroforesis capilar de zona de mangiferina en tabletas VIMANG 300 mg Quantitative determination through capillary zone electrophoresis of mangiferin in 300 mg VIMANG tablets
Harold Curiel Hernández,Hermán Vélez Castro,Janet Lora García
Revista Cubana de Farmacia , 2011,
Abstract: La mangiferina se seleccionó como marcador en el control de calidad del ingrediente farmacéutico activo VIMANG y sus formulaciones, que se han empleado como suplemento nutricional, cosmético y fitomedicamento. El trabajo tuvo como objetivo la validación del método electroforesis capilar para la determinación cuantitativa de mangiferina en la formulación farmacéutica tabletas VIMANG 300 mg. Se evaluaron la especificidad, linealidad, exactitud y precisión. Los resultados obtenidos demostraron que el método fue específico, al no existir interferencias de los excipientes o sus productos de degradación. La linealidad mostró un coeficiente de correlación de 0,9979 en el intervalo de concentraciones estudiado. Los coeficientes de variación para la repetibilidad y la precisión intermedia fueron menores de 2 %. La exactitud mostró un recobrado del 100,20 % que no difiere significativamente de 100 %. En conclusión, el método validado es específico, lineal, preciso y exacto, y constituye una alternativa ventajosa al método cromatografía líquida de alta resolución establecido con anterioridad en el laboratorio. Mangiferin was selected as marker in the quality control of active principle VIMANG and its formulations, which have been used as nutritional supplement, cosmetic, and phytomedication. This paper was aimed at validating the capillary electrophoresis method for the quantitative analysis of mangiferin in the pharmaceutical formulation 300 mg VIMANG tablets. The specificity, linearity, accuracy and precision were assessed. The results showed the method specificity owing to lack of interference by the excipients or their degradation products. Linearity showed a correlation coefficient of 0.9979 in the studied concentration range. The variation coefficients for repeatability and intermediate precision were less than 2 %. Accuracy reached a recovery rate of 100.20 % that is not statistically different from 100 %. It may be concluded that the validated method is specific, linear, precise and accurate and could be an advantageous alternative to the high resolution liquid chromatography method used at the lab setting.
Alcaloides en la especie cubana Croton micradenus Urb
Armando Payo Hill,Daisy Sandoval López,Hermán Vélez Castro,Marledis Oquendo Suárez
Revista Cubana de Farmacia , 2001,
Abstract: Se emprendió el estudio del contenido de alcaloides en las hojas y tallos de la especie endémica cubana, potencialmente medicinal, Crotón micradenus Urb. Para la extracción y purificación de dichos metabolitos se utilizaron solventes orgánicos y métodos cromatográficos de separación por columna y placa. Mediante métodos espectroscópicos de UV, IR, Masa y RMN 1H y 13C, así como por la medición de sus constantes físicas, se caracterizaron 4 de los 6 alcaloides aislados, de ellos 3 morfinandienonas: ocobotrina, sinoacutina y 8,14 dihidrosalutaridina y una aporfina: isoboldina. The study of the content of alkaloids in the leaves and stems of the Croton micradenus Urb Cuban endemic species, which is potentially medicinal, was conducted. Organic solvents and chromatographic methods of separation by column and plate were used for the extraction and purification of these metabolites. 4 of the 6 isolated alkaloids, 3 of them morphinandienones: ocobotrine, sinoacutine and 8,14-dihydrosalutaridine and an aporphine (Isobol-dine) were characterized by spectroscopic methods of UV, IR, Mass and NMR 1H and 13C, as well as by the measurement of their physical constants.
Estudio químico en especies cubanas del género Annona II: Annona sclerophylla Safford
Daisy Sandoval López,Armando Payo Hill,Hermán Vélez Castro
Revista Cubana de Farmacia , 2002,
Abstract: Se informan los resultados obtenidos del estudio del contenido de alcaloides en las hojas y tallos de la especie endémica cubana Annona sclerophylla, de discreta actividad antimicrobiana. Para la extracción y purificación de dichos metabolitos se utilizaron solventes orgánicos y métodos cromatográficos de separación por columna. Con el empleo de técnicas espectroscópicas de UV, IR, masa y RMN1H y 13C, así como por la medición de sus constantes físicas, se identificaron los alcaloides isocorypalmina y liriodenina, y los compuestos (-)-kau-16-en-19-oico y (-)-kauran-16alfa-o1. This paper presents the results of the study of the alkaloid contents in leaves and stems of the Cuban endemic species called Annona sclerophylla that has modest antimicrobial effects. For the extraction and purification of such metabolites, organic solvents and chromatographic methods of separation by columns are used. Spectroscopic techniques like UV, IR, mass and NMR1H and 13C as well as the measurement of physical constants allowed identifying alkaloids isocorypalmine and liriodenine, and compounds (-)-kau-16-en-19-oico and (-)-kauran-16μ-o1.
Aislamiento y efecto antiinflamatorio de un alcaloide de Zanthoxylum elephantiasis Macf (Rutaceae) introducida en Cuba
Kethia González-García,Hermán Vélez Castro,Lauro Nuevas Paz,Lucía Márquez Montiel
Boletín Latinoamericano y del Caribe de Plantas Medicinales y Aromáticas , 2008,
Abstract: El alcaloide canthin-6-ona fue aislado de Zanthoxylum elephantiasis Macf por Cromatografía Líquida a Vacío e identificado mediente experimentos de RMN. A este compuesto se le determinó su efecto anti-inflamatorio usando el modelo de edema en la pata inducido por carragenina. El alcaloide fue administrado intraperitonealmente a dosis de 0,3; 3 y 30 mg/kg. La inhibición de la formación del edema fue independiente de la dosis en la primera hora y dependiente de la dosis a las 3 y 5 horas después de la administración de la carragenina. Este trabajo muestra por primera vez el efecto antiinflamatorio de canthin-6-ona.
Estudio fitoquímico de la especie Hibiscus elatus S.W.
Márquez Hernández,Ingrid; Cuellar Cuellar,Armando; Martínez Pérez,Jorge; Alemán Sánchez,Alejandro; Lora García,Janette; Vélez Castro,Hermán;
Revista Cubana de Farmacia , 1999,
Abstract: a preliminary phytochemical study of hibiscus elatus species was undertaken. a phytochemical sieving of fresch dry material made it possible to obtain positive results for mucilages, reducing substances, anthocyamins, aminoacids, tanines and flavonoids. anthocyamines were determined to be affected during dryng process. for carry ing uot the chemical study, the plant was mecrated into 4 solvents (a, b, c and d fractions). taking a and b fractions as a basis, product he1 was isolated and analyzed by ultra - violet, infrared, nuclear magnetic resonance, proton and carbon 13 spectroscopies as well as special techniques and mass spectrometry. this resulted in the identification of this product as gossypitrin flavonoid. fraction c was fractioned by silicagel absorption - desorption methods which allowed us to detec rutin and quercetin. the identified flavonoids are reported for the first time in this species.
Continuity and general perturbation of the Drazin inverse for closed linear operators
N. Castro González,J. J. Koliha,V. Rako evi
Abstract and Applied Analysis , 2002, DOI: 10.1155/s1085337502002890
Abstract: We study perturbations and continuity of the Drazin inverse of a closed linear operator A and obtain explicit error estimates in terms of the gap between closed operators and the gap between ranges and nullspaces of operators. The results are used to derive a theorem on the continuity of the Drazin inverse for closed operators and to describe the asymptotic behavior of operator semigroups.
Growth Kinetics of Vegetative and Reproductive Organs of Guava (Psidium guajava L.) in Iguala Guerrero, Mexico  [PDF]
Agustín Damián Nava, Víctor A. González Hernández, Manuel Nava Jaimes, Elías Hernández Castro, Dolores Vargas álvarez, Gemima Díaz Villase?or, Francisco Palemón Alberto, Blas Cruz Lagunas
Agricultural Sciences (AS) , 2014, DOI: 10.4236/as.2014.514157
Abstract: In the Mexican tropics the guava trees can grow and produce in any season, so they can be har-vested out of the period of high competition marketing (Summer). It?studied the growth kinetics of leaves and fruits of guava trees at the dry tropical conditions of the State of Guerrero, in guava trees of four years old and was evaluated a non-destructive method for measuring leaf area from November to May. 100 sheets of 10 randomly selected trees were cut. It was found that leaf length X the width X 0.72581647 (conversion factor) gave an estimated leaf area which?was significantly correlated with that obtained by the integrator of leaf area. Both in length and width the leaf growth kinetics were sigmoid with three growth stages: In Stage I (15 days) leaves grew 21.2% and 21.5%; in Stage II (26 days) grew 73.6% and 68%; and in Stage III (30 days). They Increased 5.2% and 10.5% in the primary and secondary sprouts. The fruit growth in its equatorial and polar diameters corresponded to a double sigmoid kinetics. In Stage I (61 days) it reached 1.9 and 2.3 cm; in Stage II (62 - 102 days) it reached 3.09 and 3.62 cm; and in Stage III (103 to 126 days) it reached 4.63 and 5.13 cm, as well the physiological maturity of fruit.
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