Antioxidant Capacity through Electrochemical Methods and Chemical Composition of Oenocarpus bataua and Gustavia macarenensis from the Ecuadorian Amazon.

This study evaluated the antioxidant properties and chemical composition of the seeds, pulp and peels of Ungurahua (Oenocarpus bataua) and Pasu (Gustavia macarenensis)-fruits, native to the Ecuadorian Amazon. The antioxidant capacity was measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and cyclic voltammetry (antioxidant index 50 (AI50)) assays; differential pulse voltammetry was used to evaluate antioxidant power using the electrochemical index. The total phenolic content, as well as the yellow flavonoid and anthocyanin content, were quantified via spectrophotometry. In addition, the trans-resveratrol and ascorbic acid content were evaluated through high performance liquid chromatography (HPLC). Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) was used to identify secondary metabolites with possible therapeutic properties. Results showed that the Pasu peel and seed extracts had the highest antioxidant capacity, followed by the Ungurahua peel; these results were consistent for both spectroscopic and electrochemical assays. HPLC and UPLC-MS analysis suggest that Oenocarpus bataua and Gustavia macarenensis are important sources of beneficial bioactive compounds.

Frequency-dependent selection for rare genotypes promotes genetic diversity of a tropical palm.

Negative frequency-dependent selection among species is a key driver of community diversity in natural systems, but the degree to which negative frequency-dependent selection shapes patterns of survival and genetic diversity within species is poorly understood. In a 5-year field experiment, we show that seedlings of a tropical palm with rare genotypes had a pronounced survival advantage over seedlings with common genotypes, with effect sizes comparable to that of light availability. This 'rare genotype advantage' led to an increase in population-wide genetic diversity among seedlings compared to null expectations, as predicted by negative frequency-dependent selection, and increased reproductive success in adult trees with rare genotypes. These results suggest that within-species negative frequency-dependent selection of genotypes can shape genetic variation on ecologically relevant timescales in natural systems and may be a key, overlooked source of non-random mortality for tropical plants.

Frugivoría y dispersión de semillas de la palma Oenocarpus bataua (Arecaceae) en un bosque de los Andes colombianos / Frugivory and seed dispersal Oenocarpus bataua palm (Arecaceae) in a forest from the Colombian Andes

Seed dispersal is a key process that determines the spatial structure and dynamics of populations of plants, establishes the potential area of recruitment and in this way, the basis for subsequent processes such as predation, germination, competition and growth. The purpose of this research was to identify the guild of frugivores of the Oenocapus bataua palm in fragments of Andean forest, determine the effective dispersers and relate the spatial distribution of palm populations with the dispersion of seeds. To this end, between August 2005-June 2006, observations of the removal of fruits from eight clusters were done, and counting of consumption of fruits beneath 78 palms with mature fruits was undertaken; focal observations of 13 individuals during 90 hours; registration of frugivory with photographic traps during 165 days/nights for a total of 195 photographs and 144 consumption events; experiments with dispersion using 751 perforated fruits/seeds attached to strings and finally, plots to determine spatial distribution all were carried out. In the study area at least five species of mammals ate, dispersed, buried (Sciurus granatensis, Microsciurus mimulus, Dasyprocta punctata y Proechimys sp.), cover (Marmosa robinsoni) and carried the fruits of O. bataua off to caves (Marmosa robinsoni y Proechimys sp.) without damaging the seed. A 21.7% of the fruits were dispersed, 13.2 gnawed or peeled, 5.6% covered, buried and carried to caves. The average distance of removal of seeds and fruits was 3.1m although in a lesser proportion, dispersion events of >50m were recorded. The abundant production of fruits, their size and weight, their intense removal by frugivores, the short dispersion distances, the absence of large size frugivores (reduced by hunting and fragmentation), that might perform long-distance dispersion, and the increase of rodents, especially squirrels, that strongly pressure the fruit resource, generate a spatially restricted ...

En zonas bajas tropicales, en bosques continuos y relativamente poco intervenidos, los frutos de la palma Oenocarpus bataua Mart., son consumidos por diversas especies de vertebrados, sin embargo, no hay estudios de dispersión de más largo plazo con esta especie. Entre agosto 2005-septiembre 2006 se realizaron observaciones de remoción de frutos, conteo de frutos comidos, observaciones focales, registros de frugivoría mediante trampas fotográficas, experimentos de dispersión y parcelas para determinar distribución espacial de Oenocarpus bataua. Cinco especies de mamíferos comen, dispersan, entierran (Sciurus granatensis, Microsciurus mimulus, Dasyprocta punctata y Proechimys sp.), tapan (Marmosa robinsoni) y llevan a las cuevas (Marmosa robinsoni y Proechimys sp.), los frutos de O. bataua, sin dañar la semilla. El 21.7% de los frutos fueron dispersados, 13.2% roídos o pelados, 5.6% tapados, enterrados y llevados a cuevas. La distancia media de remoción de semillas y frutos fue 3.1m, aunque en menor proporción se registraron eventos de dispersión > a 50m. La abundante producción, el tamaño, el peso, la intensa remoción de los frutos por frugívoros, las cortas distancias de dispersión, la ausencia de frugívoros de gran porte disminuidos por cacería y fragmentación, encargados de la dispersión de larga distancia y el aumento de roedores, especialmente ardillas que presionan fuertemente el recurso frutos, generan una lluvia de semillas espacialmente restringida, posiblemente responsable de los patrones de distribución agregados en semillas, plántulas y posteriormente en juveniles y sub-adultos.

Estudio comparativo del consumo de aceite de oliva virgen o seje sobre el perfil lipídico y la resistencia a la oxidación de las lipoproteínas de alta densidad (HDL) del plasma de rata / Comparative study of the consumption of virgin olive oil or seje on lipid profile and oxidation resistance of high density lipoprotein (HDL) of rat plasma

Nosotros comparamos los efectos del consumo de aceite de seje (Oenocarpus bataua), con respecto el de oliva virgen sobre la concentración de los lípidos del plasma y de la susceptibilidad de oxidación in vitro de las lipoproteínas de alta densidad (HDL) en la rata Sprague Dawley. Dos grupos de 10 ratas macho, fueron alimentados ad libitum por un lapso de 8 semanas, con una dieta purificada que contenía 10g aceite de seje u oliva/100 g de dieta (GS y GO respectivamente). Se extrajo la sangre a los animales previo ayuno de 14 horas. El plasma fue aislado por centrifugación, y las fracciones de lipoproteínas se separaron por ajuste de densidad y ultracentrifugaciones sucesivas. Las HDL de ambos grupos fueron oxidadas por incubación con iones cobre. La diferencia de susceptibilidad de oxidación de las HDL fue estudiada midiendo la formación de sustancias reactivas al ácido tiobarbitúrico (TBARS) a las 3 horas. Las ratas del GO presentaron una disminución estadísticamente significativa en la concentración de los triglicéridosTG (p<0.05) comparada con las ratas del GS. Las HDL del GS experimentaron una disminucion estadisticamente significativa de la susceptibilidad de oxidacion de las HDL respecto las HDL GO. Esto puede ser atribuido a la mas baja concentracion de acidos grasos poliinsaturados (AGPI) en las HDL GS comparado con las HDL del GO.

We compared the effect of the consumption of seje oil (Oenocarpus bataua), with that of olive oil, on plasma lipids and susceptibility in vitro to oxidation of high density lipoprotein (HDL) in the rat. Two groups of ten male Sprague Dawley rats were fed ad libitum, for a lapse of eight week, with a purified diets with 10g de seje oil or olive oil/ 100 g of diet (GS y GO respectively). The animals were exsanguinated at the end of the experimental after a 14 hour fast. Plasma was isolated by centrifugation, and the fractions of lipoproteins were separated from the plasma by sequential ultracentrifugation. Rats of GO had a statistically significant lower in concentration of TG (p.