Revista Boliviana de Química

THEORETICAL MECHANISTIC VIEWS FOR SYNGAS, METHANOL, FISCHER-TROPSCH AND WACKER REACTIONS OF NATURAL GAS

ABSTRACT Theoretical mechanistic proposals for Syngas Reaction, Methanol Reaction, the Fischer Tropsch Reaction and the Wacker Reaction, used in the natural gas industry are here explained under the scope of the structural theory.

RESUMEN Sobre las base de la teoría estructural, se proponen mecanismos de reacción teóricos para las reacciones de la industria del gas natural conocidas como Syngas, Síntesis de Metanol, Fischer Tropsch y la reacción de Wacker.

POLYOXYGENATED FLAVONOIDS FROM BACCHARIS PENTLANDII

ABSTRACT Three highly oxygenated flavonoids were isolated from the leaves of the medicinal plant Baccharis pentlandii commonly known as "Chilca clara" Mayu chilca or simply "Chilca". Flavonoids were identified as: 5,4'dihydroxy-6,7,8,3 -tetramethoxyflavone 8-Methoxycirsilineol (1), 5,4'-dihydroxy-6,7,8-trimethoxyflavone Xanthomicrol (2) and 5,3',4'-trihydroxy-6,7,8-trimethoxyflavone Sideritoflavone (3) by spectroscopic methods. The compounds are the major chemical constituents in the plant and they have proved to be cytotoxic as well as apoptotic substances giving thus the species a potential interest against cancer.

RESUMEN Tres flavonoides altamente oxigenados fueron aislados a partir de las hojas de la planta medicinal Baccharis pentlandii D.C. comúnmente conocida como "Chilca clara", "Mayu Chilca" o simplemente "Chilca". Los flavonoides fueron identificados como: 5,4'-dihidroxi-6,7,8,3'-tetrametoxiflavona 8-Metoxicirsilineol (1), 5,4'-dihidroxi-6,7,8-trimetoxiflavona Xantomicrol (2) y 5,3',4'-trihidroxi-6,7,8-trimetoxiflavona Sideritoflavona (3) mediante métodos espectroscópicos. Los compuestos identificados son mayoritarios en la planta y tienen antecedentes como citotóxicos y apoptóticos lo cual confiere a la especie un potencial interés contra el cáncer

PERSPECTIVAS EN EL PROCESAMIENTO DE MATERIALES-ELECTRODOS PARA BATERÍAS DE ION LITIO EN BOLIVIA

ABSTRACT The existing aspects about synthesis, characterization and electrochemical properties of different electrodes for lithium ion batteries are analyzed. Identification and synthesis of precursors are included and also the processes of these materials obtaining in Bolivia. The commercial properties for these materials offered by different companies are mentioned. Finally local synthesis of two cathode electrodes (LiMn2O4) and (LiFePO4) from potential precursors present in Bolivia are reported.

RESUMEN Se analiza la síntesis, caracterización y las propiedades electroquímicas de diferentes electrodos para baterías de ion litio, identificándose los precursores y los métodos de síntesis, resaltando los procesos de los materiales obtenidos en Bolivia, y las propiedades comerciales ofertadas para estos materiales por diferentes empresas. Finalmente se hace la identificación de los procesos de obtención para dos electrodos catódicos (LiMn2O4) y del (LiFePO4), a partir de potenciales precursores existentes en Bolivia.

EVALUACIÓN DEL EFECTO INMUNOMODULADOR DEL ÁCIDO ÚSNICO SOBRE LA CAPACIDAD FAGOCÍTICA, ADHERENCIA, QUIMIOTAXIS CELULAR Y CITOTOXICIDAD SOBRE MONOCITOS Y POLIMORFONUCLEARES

ABSTRACT This study describes the evaluation of activities cytotoxic and immunomodulating effect of the acid úsnico, secondary metabolite obtained from a lichen, Usnea sp., with a high potential leishmanicidal in vitro (IC50 10.3 ug/mL) according to research of the I. I. F. B. collected in the locality of: Pazña (Oruro, Bolivia), which is attributed to him a variety of uses in traditional medicine as be antibacterial and antifungal. The cytotoxic activity was evaluated against human cells from peripheral blood (monocytes and polymorphonuclear leukocytes), at concentrations less than or equal to 250 µg/mL, taking that the CC50 of monocytes exposed to acid úsnico per 24 hours was 63.5 µg/mL and at 48 hours was 58.9 µg/ml in relation to the Glucantime that at the same incubation time was 45.3 µg/ml and 38.6 µg/ml for polymorphonuclear cells at 6 hours of exposure showed a CC50 of 58.9 µg/ml and 12 hours a CC50 of 54.3 µg/ml, the Glucantime in the same incubation period showed a CC50 of 43.5 µg/ml and 36.5 µg/ml. On the other hand, the effect inmunomodulador of the sour úsnico specifically on the quimiotaxis, adherence, fagocitosis and the activity total hemolítica of the complement, having that the sour úsnico favors the quimiotaxis from the monocitos to the concentrations of 31,2 and 15,6 µg / mL, it increases the capacity of cellular adherence of the monocitos and polymorphonuclear cells at concentrations greater than 125 µg/ml in general reduces the percentage of cells with capacity to phagocytose at concentrations greater than 15.6 µg/ml and has an effect on the hemolytic activity of the complement system in the range of concentrations ranging between 125 and 15.6 µg/ml was a decrease of 50 % of the hemolytic activity of the complement system. These results provide a basis to suggest that the Acid Úsnico has potential for the development of drugs against Leishmania, which must be validated in future studies in vivo in animal models.

RESUMEN Este estudio describe la evaluación de las actividades citotóxica y el efecto inmunomodulador del ácido úsnico (AU), metabolito secundario obtenido de un liquen, Usnea sp., con un alto potencial leishmanicida in vitro (CI50 10,3 µg/mL) según investigaciones del I.I.F.B., especie colectada en la localidad de Pazña (Oruro, Bolivia), a la que se le atribuye una variedad de usos en la medicina tradicional como ser antibacteriano y antifúngico. La actividad citotóxica se evaluó contra células humanas de sangre periférica (monocitos y polimorfonucleares), a concentraciones menores o iguales que 250 µg/ml, teniendo que la CC50 de los monocitos a las 24 horas fue de 63,5 |ig/l y a las 48 horas fue de 58,9 µg/ml, con relación al Glucantime fue de 45,3 µg/ml a las 24 horas y 38,6 µg/ml a las 48 horas, para las células polimorfonucleares a las 6 horas de exposición mostró una CC50 de 58,9 µg/ml y a las 12 horas un CC50 de 54,3 µg/ml, el Glucantime en el mismo periodo de incubación mostró una CC50 de 43,5 y 36,5 µg/ml. Por otra parte, el efecto inmunomodulador del AU específicamente sobre la quimiotaxis, adherencia, fagocitosis y la actividad hemolítica total del complemento favorece la quimiotaxis de los monocitos a las concentraciones de 31,2 y 15,6 µg/ml, incrementa la capacidad de adherencia celular de los monocitos y células polimorfonucleares a concentraciones mayores a 125 µg/ml, en general disminuye el porcentaje de células con capacidad de fagocitar a concentraciones mayores a 15,6 µg/ml y tiene efecto sobre la actividad hemolítica total del sistema del complemento ya que en el rango de concentraciones comprendidas entre 125 y 15,6 µg/ml produjo una disminución del 50% de la actividad hemolítica total del sistema del complemento. Estos resultados aportan bases para sugerir que el AU tiene potencial para el desarrollo de medicamentos contra Leishmania, el cual debe ser validado en estudios futuros en modelos animales

OBTENCIÓN DE JARABE DE GLUCOSA A PARTIR DE LA HIDRÓLISIS ENZIMÁTICA DE ALMIDÓN DE BANANO, MUSA CAVENDISH

ABSTRACT Banana (Musa cavendish) is a fruit that takes place in Ecuador and a part of its production is being rejected. For this reason this project is focused on the usage of this resource in order to obtain glucose syrup from its starch by an enzymatic pathway. Previous to hydrolysis the substrate needs to be prepared using a process of washing and drying of banana fruits. Hydrolysis was made in two stages. For the first hydrolysis ± -amylase from Bacillus amyloliquefaciens was used; which allowed to degrade starch to dextrins. In this stage some tests were made to calculate the optimal time for the hydrolysis, which was of 2 hours. Also, dextrins obtained were analyzed by gel permeation chromatography, obtaining dextrins of 9, 10 and 11 glucose units. In the second stage amyloglucosidase from Aspergillus niger was used. In this stage an experimental design was performed; such design was completely at random with factorial model of 3², corresponding to the combination of time and amount of enzyme, with two repetitions. The studied variables were yield and crystallinity. The recommended treatment was of 1,5 milliliters of enzyme and 14 hours of hydrolysis. Treatment that corresponds to a glucose yield of 90,14%.

RESUMEN El banano (Musa cavendish) es una fruta que se produce en el Ecuador y una parte de su producción está siendo desechada. Por lo que en este trabajo se estudió la utilización de este recurso para la conversión de su almidón en jarabe de glucosa, por medio enzimático. Previo a la hidrólisis se preparó un sustrato mediante lavado y secado. El proceso de hidrólisis se realizó en dos etapas. En la primera se utilizó ± -amilasa proveniente de Bacillus amyloliquefaciens; la cual permitió degradar el almidón hasta dextrinas. En esta etapa se realizaron pruebas para calcular el tiempo óptimo de hidrólisis, el cual fue de 2 horas. También se analizaron las dextrinas obtenidas de la hidrólisis mediante cromatografía de permeación en gel, siendo estas de 9, 10 y 11 unidades de glucosa. En la segunda etapa del proceso se utilizó amiloglucosidasa proveniente de Aspergillus niger. En esta etapa se realizó un diseño experimental completamente al azar con modelo factorial de 3² correspondiente a la combinación de tiempo y cantidad de enzima, con dos repeticiones. Las variables estudiadas fueron rendimiento y cristalinidad. El tratamiento recomendado fue de 1,5 ml de enzima y 14 horas de hidrólisis. Tratamiento que corresponde a un rendimiento de glucosa del 90,14%.

XYLANASE PRODUCTION USING BARLEY STRAW BY BACILLUS SP. LB-4 ISOLATED FROM LAGUNA BLANCA, POTOSI-BOLIVIA

ABSTRACT Bacterial strains isolated from water samples collected from Laguna Blanca, Potosi-Bolivia and deposited at Biotechnology Center, Cochabamba-Bolivia, were subjected to xylanolytic enzyme production studies. Among these, 20 strains were selected as positive in xylanolytic enzyme production in liquid medium, using barley straw as sole carbon source and subjected to morphological and biochemical studies. Enzyme production in liquid medium identified strain LB-4 as the best enzyme producer with 10 U/ml xylanolytic activity. Partial characterization of the produced enzyme revealed its display maximum activity values at pH 9, 50°C y 0% (w/v) NaCl concentration, thus exhibiting thermo-alkalitolerant properties. The 16S rDNA gene sequence analysis showed 99% similarity between strain LB-4 and Bacillus pumilus (embAJ494727).

RESUMEN Estudio sobre la producción de enzimas xilanolíticas en bacterias colectadas en Laguna Blanca, Potosi-Bolivia. La caracterización parcial de las enzimas producidas que mostraron una máxima actividad a un pH 9 a una concentración de NaCl de 50°C y 0% (w/v) exhibiendo así propiedades termo-alkalitolerantes. El análisis de la secuencia del gen 16S rDNA mostró un 99% de similaridad entre la cepa LB-4 y Bacillus pumilus (embAJ494727).

APPLICATION OF FERRIPROTOPORPHYRIN BIOCRYSTALLIZATION INHIBITION TEST TO FIND ANTIPLASMODIAL COMPOUNDS IN THE FLORA OF THE "ZONGO VALLEY" - BOLIVIA

ABSTRACT Among the different tests or chemical reactions that explain the possible inhibition mechanisms of Plasmodium falciparum growth, we have chosen the Ferriprotoporphyrin biocrystallization inhibition test (FBIT) to evaluate the pharmacological properties of 65 plants from the Bolivian flora. A bioguided phytochemical separation of Brachyotum microdon, one of the most active plant, was sought using the FBIT test. The isolated active compounds belong to two types of metabolites the fatty alcohols and the triterpenes. Among the triterpenes, we have p-sitosterol (1), oleanolic acid (2), ursolic acid (3) and corosolic acid (4) as sources of the activity on FBIT.

QUENCHING OF CERENKOV RADIATION FROM NATURALLY OCCURRING ⁴⁰K BY DYES AS PHOTOMETRIC TECHNIQUE

ABSTRACT The beta emitter 40K isotope contained in KCl solutions, produces photons known as Cerenkov radiation measurable by liquid scintillation spectrometry. A set of dyestuffs and metal ion complexes showed quenching effects against Cerenkov light. Studied systems follow the Stern-Volmer equation. Counting ratiosvs. quencher concentration [Q], are linear, yielding Ks.v constants. High Ks.v values indicate highly quenched systems. Congo red and Methylene blue havevalues 20.0xl0(4) M"¹ and 2.27xl0(4) M"¹ respectively. Crystal violet does not act as quenching agent in the range up to O.lrnM, and has a lowestvalue, about 10"4 M"¹. There are linear correlations between visible absorbances atand counting ratios Neither inorganic colorless salts as lead nitrate or zinc nitrate, nor pure solvents as acetonitrile, acetone, methanol and ethyl acetate showed quenching properties. As a result, a procedure suitable for dyestuff determinations based on quenching of Cerenkov radiation has been accomplished.

ESTUDIO DEL FRUTO COMESTIBLE DE LA ESPECIE VEGETAL GARCINIA MADRUNO

ABSTRACT Fruits of the vegetal species Garcinia madruno were surveyed. This is a species known in the Bolivian Amazonian region under the common names of "Camururu" and "Ocoro". The fruits were collected at the Ixiamas village and their surroundings in the province Abel Iturralde, department of La Paz. In the investigation of the eatable part of the fruit, a bromatological preliminary study was carried out. The macro and micro nutrients were determined, as well as the taste of the fruit and of the handmade elaborated product. A preliminary phytochemical study was also performed in fruits.

RESUMEN Se realizó un estudio de frutos de la especie vegetal Garcinia Madruno, conocido en la parte amazónica del departamento de La Paz con el nombre de Camururu y en otras regiones con el nombre de Ocoró. Los frutos se recolectaron en la localidad de Ixiamas, capital de la provincia Abel Iturralde, que dentro del departamento de La Paz, forman parte de la Amazonia de Bolivia. En la investigación de la parte comestible del fruto, se realizó un estudio bromatológico preliminar, la determinación de macro y micro nutrientes, también la degustación del fruto y del producto elaborado artesanalmente a partir de éste. Además se realizó un estudio fitoquímico preliminar

CALYCIN AND PHYSCION FROM THE LICHEN CANDELARIA CONCOLOR

ABSTRACT Calycin, Physcion and Mannitol were isolated from Candelaria concolor, lichen specie. Molecular structures, were elucidated by 2D- NMR spectroscopy techniques.

RESUMEN Calycin, Physcion y el Manitol fueron aislados de la especie liquenica Candelaria concolor. La elucidación estructural se baso en el análisis espectroscópico de RMN-2D.

PROTEIN ENRICHMENT OF ORIENTAL NOODLES BASED ON CANNA EDULIS STARCH

ABSTRACT Spray drying, drum drying and extrusion cooking were applied in order to find out the best treatment for pre-gelatinization of Canna edulis starch for noodle processing. Spray-drying process manifested to be a gentle process to modify the native starch, whereas cooking extrusion was too drastic. Adding either native or pre-gelatinized C. edulis starch to wheat flour noodles increased the solid loss. Whereas noodles made of C. edulis only, showed lower cooked weight and solid loss than commercial samples. C. edulis noodles with the best cooking stability were obtained by mixing 12 % pre-gelatinized starch, 28% native starch and 60% water, submerging in boiling water for 60 seconds, cooling in water at room temperature (17°C) for 60 seconds and drying in oven at 17°C. A protein enrichment of C. edulis noodles by adding either lupine concentrate or defatted soybean flour showed that lupine-C. edulis and soybean-C. edulis mixtures had higher solid loss than noodles prepared by using C. edulis starch only. Sensory evaluation results showed that the cooling of noodles in water at room temperature did not make differences on the appearance and texture compared to samples cooled down at 0DC. C. edulis noodles of 1.5 mm and 0.8 mm diameter showed big differences with commercial samples. Moreover an improvement on the appearance and texture of C. edulis noodles was observed by reducing the noodles diameter from 1.5 to 0.8 mm. Acceptability tests of the protein enriched noodles showed that consumers had preference for the mixture Lupine-C. edulis.

EVALUACION DE LA PRESENCIA DE METALES PESADOS Y ARSÉNICO EN SUELOS AGRICOLAS Y CULTIVOS EN TRES MICRO-CUENCAS DEL MUNICIPIO DE POOPÓ

ABSTRACT The purpose of this study was to determine the presence of heavy metals (Pb, Cd, Zn) and As in agricultural soils and representative cultivations in three Micro-basins of the municipality of the Poopó divided in parts (high, half and under). The results show that the agricultural soils of the three Micro-basins in study are contaminated by arsenic, overcoming the dangerous level of (55 mg/kg soil), for natural mineralización of the area as for the contribution of the surrounding mining in the region (dismount, copagira waters tosed to the bleakness and the rivers), situation that deserves an immediate remediation, for can to avoid the intensity of accumulation. The bean cultivations and potato eatable fraction present tendencies of accumulating bigger quantity of arsenic, ending up in some cases to overcome the máximum content in cultivations (1,7 sample mg/kg).

RESUMEN El propósito del estudio fue determinar la presencia de metales pesados (Pb, Cd, Zn) y As en suelos agrícolas y cultivos representativos en tres Micro-cuencas del municipio Poopó; divididas en tres partes (alto, medio y bajo). Se muestrearon suelos de parcelas agrícolas y cultivos fracción comestible (Papa, Haba, Cebada y Alfalfa), en puntos previamente seleccionados, según la disponibilidad, en la micro-cuenca de: Venta y Media (P1), Coriviri (P2) y Poopó (P3). Las muestras con pequeñas concentraciones se determinaron mediante el Espectrofotómetro de Absorción Atómica en llama y horno de grafito, en el laboratorio del Instituto de Investigaciones Químicas de La Paz (UMSA). La concentración de metales se evaluó con los límites máximos permisibles y los niveles peligrosos para suelo, propuesto por la Agencia Ambiental Holandesa y la Ley de Gestión Ambiental del Ecuador, los cultivos agrícolas se evaluaron con los contenidos máximos propuesto por Kabata-Pendias, 2000. Los resultados muestran que los suelos agrícolas de las tres Micro-cuencas en estudio se encuentran contaminados por arsénico, superando el nivel peligroso de (55 mg/kg de suelo), vía mineralización natural de la zona como por el aporte de la minería circundante en la región (desmontes, aguas de copagira echadas a la intemperie y a los ríos), situación que merece una remediación inmediata, para poder evitar la intensidad de acumulación. El cultivo de haba fracción comestible presentan tendencias de mayor acumulación de arsénico, llegando en algunos casos a superar el contenido máximo en cultivos (1,7 mg/kg de muestra).