Revista Boliviana de Química

CONTRIBUCIÓN A LA QUÍMICA DE LOS ACEITES ESENCIALES PROVENIENTES DEL OREGANO

ABSTRACT It is very gratifying to use various classical techniques of the phytochemistry to isolation and identification of secondary metabolites providing from plants. Layer chromatography column chromatography fine preparative, liquid chromatography of high efficiency, together with the infrared spectroscopy and the ultraviolet-visible complement these techniques essential for the study of natural products. However, identification of compounds that this wonderful natural synthesis lab generously gives us, is only possible docking techniques NMR and the mass spectrometry, which allow to determine the molecular mass and functional groups, providing more refined information about the molecular structure of these complex products. Origanum vulgare (oregano) is a species accessible, economic and easy to obtain in our region. Using drag with vapour technique and extraction solvent (methanol-water and ethanol) essential oil is extracted and proceeded with column chromatography and thin layer to separate the active ingredients of essential oil. Then proceeded to perform analysis chromatographic and mass spectra in order to determine the main constituent present in the samples.

RESUMEN Resulta muy gratificante utilizar diversas técnicas clásicas de la fitoquímica para el aislamiento e identificación de metabolitos secundarios provenientes de las plantas. La cromatografía de columna, la cromatografía de capa fina preparativa, cromatografía líquida de alta eficiencia, conjuntamente con la espectroscopía infraroja y la ultravioleta-visible complementan estas técnicas esenciales para el estudio de los productos naturales. Sin embargo, la identificación de los compuestos que este maravilloso laboratorio de síntesis natural generosamente nos regala, sólo es posible acoplando técnicas de la RMN y la espectrometría de masas, que permiten determinar la masa molecular y los grupos funcionales, brindando información más refinada sobre la estructura molecular de estos complejos productos. El Origanum vulgare (orégano) es una especie accesible, económica y de fácil reproducción en nuestra región. Utilizando la técnica de arrastre con vapor y la extracción por solvente (metanol-agua y etanol-agua) se extrajo el aceite esencial y se procedió con cromatografía de columna y en capa fina a separar los principios activos del aceite esencial. Posteriormente se procedió a realizar el análisis cromatográfico y espectros de masa, con el objeto de determinar los principales constituyentes presentes en las muestras

STUDIES ON COMPLEXATION IN SOLUTION WITH PAPER IONOPHORETIC TECHNIQUE [THE SYSTEM MERCURY(II) / NICKEL(II) / LEAD(II) - HYDROXYPROLINE]

ABSTRACT A new method, paper electrophoresis, involving the use of an ionophoretic technique is described for the study of equilibria in solution. This method is based on migration of a metal ion spot (M), under an electric field at various pHs of background electrolyte. A plot of pHs versus mobility of metal ion spots provide information about the formation of metal complexes allowing calculation of the stability of these complexes. The stability constant of ML and ML2 complex species of Hg(II), Ni(II) and Pb(II) with hydroxyproline were determined at an ionic strength of 0.1 M (perchloric acid) and at a temperature of 35º C. The stability constants of ML and ML2 complexes of metal(II) - hydroxyproline have been found to be (8.65 ± 0.02; 7.14 ± 0.05), (7.02 ± 0.04; 5.56 ± 0.07) and (4.71 ± 0.01; 3.11 ± 0.03) (log k values) for Hg2+, Ni2+ and Pb2+ complexes, respectively

STUDIES ON MERCURY(II), NICKEL(II) AND LEAD(II) BIOLOGICALLY IMPORTANT BINARY COMPLEXES WITH NORVALINE IN SOLUTION

ABSTRACT A recent technique involving the use of paper electrophoresis is described for the study of equilibria in binary complex systems in solution. This method is based on movement of a spot of metal ion in an electric field at various pHs of background electrolyte. A graph of pH versus mobility give the information for binary complexes and to calculate stability constants. The logarithm stability constants of the ML and ML2 complexes of norvaline were found to be (8.61 ± 0.03; 7.05 ± 0.07), (6.93 ± 0.05; 5.47 ± 0.03) and (4.57 ± 0.02; 3.00 ± 0.05) for the mercury(II), nickel(II) and lead(II) complexes, respectively at ionic strength 0.1 M perchloric acid and a temperature of 35 ° C

RESIDUOS DE PLAGUICIDAS ORGANOCLORADOS EN LECHE MATERNA

ABSTRACT We studied the content of residues of organochlorine pesticides in milk of mothers in gestation and lactation in 112 samples from women of the Hospital "Los Andes", La Paz Bolivia. The analytical method used was gas chromatography. Total DDT, considering the sum of ppDDE, opDDE and ppDDT is higher that other waste with 60.6% indicates it a high exposure to the insecticide

RESUMEN Se estudió el contenido residuos de plaguicidas organoclorados, en leche de madres en gestación y lactancia en 112 muestras provenientes de mujeres del Hospital Los Andes, Ciudad de El Alto, La paz Bolivia. El método analítico utilizado fue cromatografía gaseosa. El DDT total, considerando la suma de ppDDE, opDDE y ppDDT es mayor que los otros residuos con un 60,6% lo indica una alta exposición a este insecticida

Spectroscopic studies of lichen depsides and depsidones

ABSTRACT A structural study of depsides and depsidones by ¹H NMR and 13C NMR spectroscopy, in which assignments of all carbons/protons of compounds isolated from various lichens (Thamnolia vermicularis, Baeomyces roseus and Everniastrum cirrhatum) is reported. The compounds studied include thamnolic acid, decarboxythamnolic acid, baeomycesic acid, salazinic acid and atranorin. The assignments are based on variuos 1D and 2D NMR experiments, e.g. DEPT, COSY, HMQC and HMBC

Estudio in vitro de la actividad antifúngica de extractos vegetales del género Baccharis sobre Candida albicans

ABSTRACT The research goal was to find alternatives for controlling the growth of microoganism. Thus antifungal activity was determined from polar an non polar plants crude extracts of Baccharis, using non-polar and polar extracts, of Baccharis latifolia, Bacharis genistelloides, Baccharis obtusifolia, Baccharis papillosa, Baccharis santelicis, genus, against species on ATCC strains of Candida albicans. Extract of Baccharis latifolia, growth inhibition was observed

RESUMEN Con la finalidad de buscar alternativas para el control del crecimiento de microorganismos patógenos, se investigó la actividad antifúngica de plantas del género Baccharis, utilizando extractos no polares y polares, de las especies Baccharis latifolia, Baccharis genistelloides, Baccharis obtusifolia, Baccharis papillosa, Baccharis santelicis, sobre cepas ATCC de Candida albicans. Presentando actividad inhibitoria los extractos de Baccharis latifolia

PHYSICOCHEMICAL AND INFRARED SPECTRAL PROPERTIES OF BIODIESEL FUELS SYNTHESIZED FROM SOME VEGETABLE OILS

ABSTRACT A set of vegetable oils from Bolivian rain forests have been converted into biodiesel by base-catalyzed transesterification of fatty acids. Data regarding biodiesel properties dealing with feasibility of quality control procedures were obtained. Biodiesels have dynamic viscosity values in the range from 5.29 to 8.24 mPa.s at 20°C, and viscosity temperature dependences up to 90°C obey exponential functions. Dielectric constant values are between 3.75 and 4.34, whereas for diesel fuel is 2.35 ± 0.25. Measured diesel fuel density is 0.857 ± 0.015 g/cm³ at 20°C, while biodiesel densities are about 0.879 g/cm³. Temperature dependent specific gravity changes gave linear behavior between 20°C and 80°C. Heats of combustion values expressed in kJ/g are in the range 46.37 - 55.56 and a value of 49.42±2.20 for diesel fuel as reference. Measured differences do not depend on oils composition and could be attributed to the synthesis procedure. Neither water nor glycerol effects has been detected as meaningful impurities. Biodiesel-diesel fuel standard mixtures gave straight lines as calibration procedure to quantify biodiesel by infrared spectroscopy