Revista Boliviana de Química

Interaction of isoleucine with metal ions in chemical and biological systems

The stability constants of Zn2+, Cd2+ and Fe2+ complexes with isoleucine were determined by paper ionophoretic technique. The present method is based on the movement of a spot of metal ions in an electric field at various pHs of background electrolyte. A graph of pH versus mobility was used to obtain information on the binary complexes and to calculate its stability constants. Using this method, the stability constants of binary complexes metal(II) -isoleucine have been determined to be (7.24 ± 0.01, 3.48 ± 0.04); (6.90 ± 0.01, 3.25 ± 0.11) and (6.50 ± 0.03, 2.97 ± 0.07) (logarithm stability constant values) for Zn(II), Cd (II) and Fe(II) complexes respectively at ionic strength 0.01 Mol L-1 and a temperature of 35°C.

Saponins from Chenopodium Quinoa Willd and Chenopodium Pallidicaule Aellen as biocontrollers of phytopathogen fungi and hemolysis agents

Las saponinas por sus propiedades como biocontrolador o bioplaguicida de hongos fitopatógenos, como los del género Aspergillus y Fusarium, tienen la habilidad de producir ruptura de los eritrocitos, que se puede medir por el índice hemolítico. En el presente trabajo se evaluó la actividad biocontroladora de saponinas extraídas de dos especies del género Chenopodium (Quinoa y Cañihua), su posible grado de eco toxicidad y hemotoxicidad in vitro. Se trabajo con muestras otorgadas por PROINPA, la extracción de saponinas se realizó en medio acuoso. Los cuadros de crecimiento e inhibición muestran que el extracto M-16 (saponina) tiene capacidad biocotroladora sobre las cepas Bol RT-1 (Fusarium ssp) y Bol JR-1 (Aspegilius flavus) con una inhibición a los 12 días con 47,6 %, 42 % respectivamente. La ecotoxicidad sobre Daphnia magna muestran que a una concentración de 25% p/v, los extractos de saponinas no son significativamente tóxicos para el medio ambiente, los resultados de los ensayos de hemotoxicidad, presenta un valor de HC50 de 0.58 mg/ml, la hemólisis de glóbulos rojos se realizaron con la cuantificación de saponinas, se observa que a una concentración de saponina 0.320 mg/ml (muestra 12) un 32.215 % de glóbulos rojos son lisados, valor que muestra un grado de toxicidad no muy elevado. La Muestra 16 (saponina) demostró tener un efecto inhibidor eficiente sobre el crecimiento de para Aspergillus flavus y Fusarium spp. no es eficiente en un lapso de tiempo reducido, sin embargo a largo plazo si se podría controlar estas plagas, con la ventaja adicional del uso seguro para la conservación del medio ambiente como se muestra en la prueba de ecotoxicidad y segura para los usuarios como se comprueba en los ensayos de hemotoxicidad.

Saponins for its properties as a biopesticide and biocontrol of plant pathogenic fungi, such as Aspergillus and Fusarium, have the ability to produce red blood cells rupture, which can be measured by the hemolytic index. In this paper the biocontrol activity of saponins extracted from two species of Chenopodium (Quinoa and canihua) possible degree of toxicity and eco hemotoxicity, in vitro. We worked with ratings PROINPA samples, extraction of saponins was carried out in aqueous medium. Growth charts and inhibition show that the M-16 extract (saponin) has biocotroladora ability on strains Bol RT-1 (Fusarium sPp) and Bull JR-1 (Aspegilius flavus) with an inhibition at 12 days to 47.6 %, 42% respectively. Ecotoxicity of Daphnia magna show that at a concentration of 25% w / v saponin extracts are not significantly toxic to the environment, the results of tests of hemotoxicity, HC50 has a value of 0.58 mg / ml, the RBC hemolysis was performed by quantification of saponins, it is observed that at a concentration of saponin 0.320 mg / ml (sample 12) A 32. 215% of red cells are lysed, showing a value not too high toxicity. Sample 16 (saponin) proved to have an efficient inhibitory effect on growth of Aspergillus flavus and Fusarium spp. is not efficient within a short time, but long term if you could control these pests, with the added benefit of safe use for protection of the environment as shown in the proof of ecotoxicity and safe for users as checks haemotoxicity assays. Original spanish title: saponinas de chenopodium quinoa willd y cañihua chenopodium pallidicaule aellen como agente biocontrolador de hongos fitopatogenos y agente hemolisante.

Mechanistic views of stereoselective synthesis of tri-and tetra-substituted alkenes, part II; the organic chemistry notebook series, a didacticalapproach, N° 4

This is the complementing part of the previously published: "Mechanistic views of stereoselective synthesis of tri-and tetra-substituted alkenes, part I; The Organic Chemistry Notebook Series, a Didactical Approach, N° 3". As underlined in three previous papers the presentation of synthesis works in a verbal and graphical succinct manner, needs a didactical approach. Isomerically pure tri- and tetra-substituted alkenes are difficult to obtain as shown in several publications. We used a series of reactions to synthesize tri- and tetra-substituted alkenes as reviewed by W. Carruthers, and we have proposed didactical and mechanistic views for the reviewed reactions. These two latest approaches are included in the synthetic methods reviewed by W. Carruthers with respect to the "Formation of carbon-carbon double bonds". Spanish title: Vistas mecanísticas de síntesis estereoselectivas de alquenos tri y tetrasubstituidos, Parte II, Serie: El cuaderno de notas de química orgánica, un enfoque didáctico, N°4.