Plant extracts of Eugenia punicifolia (Kunth) DC., Myrtaceae, are used in Amazon region of Brazil to treat diarrhea and stomach disturbances, and as hypoglycemic medicine. We have recently shown that an aqueous extract of E. punicifolia augmented cholinergic neurotransmission in a rat phrenic nerve-diaphragm preparation. In this study, we investigated the effects of an E. punicifolia dichloromethane extract (EPEX) in a neuronal model of cholinergic neurotransmission, the bovine adrenal chromaffin cell. EPEX augmented the release of catecholamine triggered by acetylcholine (ACh) pulses but did not enhance ACh-evoked inward currents, which were inhibited by 30%. Since EPEX did not cause a blockade of acetylcholinesterase or butyrylcholinesterase, it seems that EPEX is not directly activating the cholinergic system. EPEX also augmented K+-elicited secretion without enhancing the whole-cell inward calcium current. This novel and potent effect of EPEX in enhancing exocytosis might help to identify the active component responsible for augmenting exocytosis. When elucidated, the molecular structure of this active principle could serve as a template to synthesise novel compounds to regulate the exocytotic release of neurotransmitters.

Volatile organic compounds (VOC's) are an important class of atmospheric pollutants responsible for production of photochemical oxidants, particularly tropospheric ozone in large scale causing damages in biosphere. Lung problems and ocular irritations in human beings are claimed to ozone. Increasing environmental awareness in the last years has prompted the emergence of stricter regulations covering industrial activities. Catalytic combustion is one of the most promising technologies to controlling VOC's emissions. This work is concerned with the development of low-cost efficient catalysts with high selectivity to CO and long term thermal stability for methylethylketone (MEK) combustion. Fe-Mn and 2 Cu-Mn metal oxide systems, both as bulk oxides and samples supported over peruvian natural clays modified by a pillaring process (PILC) with aluminium (Al-PILC) and titanium (Ti- PILC). All the metal oxide samples were prepared by co-precipitation. The natural clay material was interchanged with Al and Ti hydroxycations (pillars) in order to obtain pillared clays (PILC's) with high specific surface area and porosity. Supported catalysts were prepared over the uncalcined PILC's by the incipient wetness method. Fe-Mn oxides appeared to be very active catalysts. Comparing bulk samples, Fe-Mn oxide had higher activity; however supported Cu-Mn sample showed better performance. Supported samples showed better activities than their corresponding supports. Preliminary XPS studies indicate that Cu-Mn samples gave rise to strong interaction between Cu and the clay structure. This was not the case with the supported Fe-Mn oxides.

Los compuestos orgánicos volátiles (COV's) son un importante tipo de contaminantes atmosféricos responsables de la producción de oxidantes fotoquímicos, especialmente ozono troposférico, que causan daños en plantas y animales, irritación ocular y problemas respiratorios en los humanos. Por esta razón existe actualmente un fuerte interés por la reducción de las emisiones de COV's a la atmósfera. La combustión catalítica es una alternativa eficiente para el tratamiento de estos contaminantes. Este trabajo está orientado a la obtención de catalizadores de bajo coste, altamente activos, selectivos a CO2 y estables para la combustión de etilmetilcetona (MEK). Para ello se han considerado catalizadores basados en óxidos metálicos mixtos de Fe-Mn y Cu-Mn de composición equimolar, tanto másicos como soportados sobre arcillas naturales peruanas modificadas (PILC's), mediante un pilaramiento con aluminio y titanio (Al-PILC y Ti-PILC). El método de preparación utilizado con todas las muestras metálicas ha sido el de coprecipitación. La arcilla natural fue intercalada con hidroxicationes de Al y Ti (pilares), lo que ha permitido la obtención de arcillas pilaradas con alta área superficial y porosidad. Los catalizadores soportados se han preparado con la arcilla pilarada sin calcinar mediante impregnación a humedad incipiente. Los catalizadores de Fe-Mn resultaron bastante activos. La muestra másica de Fe-Mn ha sido más activa que su análoga de Cu-Mn; sin embargo, al comparar las muestras soportadas, la de Cu-Mn ha mostrado mejor actividad. Por otro lado, los óxidos metálicos soportados mostraron mejor eficiencia respecto al correspondiente soporte (arcillas pilaradas sin óxido metálico). Los resultados de caracterización por espectroscopia fotoelectrónica de Rayos X (XPS) indican que la disposición adoptada por los óxidos de Cu-Mn en la arcilla ha dado lugar a una fuerte interacción entre el cobre y la estructura. Sin embargo, esto no ha sido observado con el sistema Fe-Mn.