Departamento de Química

The 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced edema model in micedetermined the anti-inflammatory activities in vivo of argentatins A, B and D, the main cycloartenol-type triterpenes present in Parthenium argentatum. Our resultsshowed that argentatin B (ED50=1.5 x 10-4 mmols/ear) and argentatin A (ED50=2.8 x 10-4 mmols/ear) were more potent anti-inflammatory agents than indomethacin (ED50=4.5 x 10-4 mmols/ear), the reference drug. Based on these findings, we
decided to evaluate 13 derivatives of argentatins A and B. All the derivativess howed anti-inflammatory activity in the TPA-induced edema model in mice. The most active compound was 25-nor-cycloart-3, 16-dione-17-en-24-oic acid, obtained from argentatin A (ED50= 1.4 x10-4 mmols/ear). Argentatin B was assayed as
inhibitor of COX-2 activity one of the key enzymes involved in the TPA assay. The results showed that argentatin B at 15 μM doses inhibited 77 % COX-2 activity.Docking studies suggest that argentatin B interacts with Arg 120, a key residue forCOX-2 activity.

Ecuador is well known for its biodiversity and
its ancient richness. This review provides an overview of
Ecuadorian plant species in terms of the ethnobotany and
chemistry of natural products in relation to anticancer
activity. Plant species were classified into two groups:
(a) Ethnomedical species with confirmed antitumor activity
and (b) species indigenous to Ecuador with anticancer
potential. This review shows that there is a great
chemical diversity in Ecuadorian plants that can be used
for potential antitumor therapeutics, and chemical and
biological analysis confirms the biomedical use of the
plant-derived compounds as cytotoxic agents for cancer
cells.

Ecuador is well known for its biodiversity and its ancient richness. This review provides an overview of Ecuadorian plant species in terms of the ethnobotany and chemistry of natural products in relation to anticancer activity. Plant species were classified into two groups: (a) Ethnomedical species with confirmed antitumor activity and (b) species indigenous to Ecuador with anti-cancer potential. This review shows that there is a great chemical diversity in Ecuadorian plants that can be used for potential antitumor therapeutics, and chemical and biological analysis confirms the biomedical use of the plant-derived compounds as cytotoxic agents for cancer cells.

Four enyne derivatives (1-4) and quercitrin were isolated during a bioassay-guided chromatographic separation of a methanolic extract of Erigeron apiculatus. Matricarialactone (1) and lachnophyllumlactone (2) showed a high fungitoxic activity against Pyricularia oryzae. Matricaria acid methyl ester (3) and lachnophyllum acid methyl ester (4) were, instead, less active.

Phytochemical investigation of secondary metabolites of the Ecuadorian plant Schistocarpha eupatorioides (Fenzl) Kuntze (Asteraceae) afforded three phytyl fatty acid esters along with a mixture of unidentified polyprenols, the very well known sterols beta-sitosterol and stigmasterol, and their corresponding fatty acid esters and glucosyl derivatives. The structures of the compounds were elucidated on the basis of various spectroscopic means. In addition, a volatile fraction was separated the composition of which, comprising sesquiterpene hydrocarbons as the main fraction, was determined by GC-MS.

Four enyne derivatives (1-4) and quercitrin were isolated during a bioassay-guided chromatographic separation of a methanolic extract of Erigeron apiculatus. Matricarialactone (1) and lachnophyllumlactone (2) showed a high fungitoxic activity against Pyricularia oryzae. Matricaria acid methyl ester (3) and lachnophyllum acid methyl ester (4) were, instead, less active.

La modelación matemática describe por medio de fórmulas las variables, parámetros y operaciones que intervienen en un determinado sistema. La red de agua potable del sector Zamora Huayco de la ciudad de Loja, Ecuador, se modeló hidráulica y matemáticamente en la presente investigación. En ella se aplicaron dos modelos matemáticos diferentes: determinístico y estocástico. El Modelo determinístico consistió en la obtención de la Curva de Variación Horaria de Demanda (CVHD). La CVHD fue obtenida de los consumos y presiones de la red principal, y de puntos seleccionados estratégicamente. Para el procesamiento de datos de la CVHD se utilizó los softwares EPANET y MatLab. El método de Pulsos Rectangulares de Poisson (PRP) se aplicó para el enfoque estocástico y fue desarrollado con el software MatLab. En el modelo PRP se consideró la variación instantánea de consumos y presiones domésticas como una distribución aleatoria uniforme. Los resultados obtenidos en esta investigación fueron eval...

Resumen El interés de la investigación fue producir un modelo para formación de profesores de matemática. El paradigma metodológico que orientó este trabajo fue el cuali-cuantitativo. El estudio fue descriptivoexplicativo-documental y el diseño fue no experimental y transeccional. El marco teórico muestra la propuesta de diferentes autores, donde se realiza un análisis de los diferentes modelos para formación de profesores de matemática. Finalmente se concluye que los modelos de formación analizados tienen etapas y principios que los conforman; pero no es usual encontrar un conjunto de características que describan en detalle cómo funciona el modelo durante un proceso de formación.

The higher molecular weight and low solubility of amphotericin B (AmB) hinders its topical administration. The aim of this study was to incorporate Bursera graveolens essential oil into an AmB topical gel (AmB + BGEO gel) in order to promote the diffusion of the drug through the skin in the treatment of cutaneous candidiasis. AmB + BGEO gel formulation was determined using a factorial experiment. Physical and chemical parameters, stability, in vitro release profile and ex vivo permeation in human skin were evaluated. In vitro antimicrobial activity was studied using strains of C. albicans, C. glabrata and C. parapsilosis. The tolerability was evaluated using in vitro and in vivo models. AmB + BGEO gel presented appropriate characteristics for topical administration, including pH of 5.85, pseudoplastic behavior, optimal extensibility, as well as high stability and acceptable tolerability. In vitro release studies showed that the formulation releases the drug following a Boltzmann sig...

Yacuambi river waters were good and medium according to Water Quality Index. • Water is inadequate for drinking, preservation of aquatic life and irrigation. • Color, As and fecal coliforms exceeded human consumption limits in all samples. • All samples exceeded the threshold of preservation for aquatic life for Pb. • Yacuambi river waters are unsuitable for irrigation due to As and fecal coliforms.

Las cremas son pomadas multifásicas constituidas por dos fases una lipofílica y otra hidrofílica. Estas pueden se clasificadas en dos grupos: hidrófobas cuando la fase continua o externa es la fase lipófila debido a la presencia en su composición de emulgentes tipo agua/aceite e hidrófilas cuando la fase continua o externa es la fase acuosa y su composición de emulgentes es de tipo aceite/agua. La importancia del control de calidad de un producto farmacéutico sirve para constatar que el resultado este dentro de los parámetros referenciales, por lo tanto, el control se divide en propiedades organolépticas las mismas que son color, olor, aspecto o untuosidad al tacto. Dentro de las propiedades físicas tenemos viscosidad que no fue evaluada, pH con un resultado de 8.66, tipo de emulsión con colorante en este caso hidrosoluble y microscopia en la que se observó una mezcla heterogénea. Por último, se realizaron pruebas de estabilidad para lo cual se sometió la muestra a centrifugación y se logró observar la separación de ambas fases. Las buenas prácticas de manufactura determinaran la calidad del producto farmacéutico.