A pesar de que la contaminación del aire constituye uno de los principales problemas en la ciudad de Loja, actualmente no existe una estrategia para monitorear las emisiones de contaminantes. Los líquenes epífitos han sido ampliamente utilizados como bioindicadores de la contaminación atmosférica, debido a que obtienen la mayor parte de nutrientes del aire, lo que los hace muy sensibles a los cambios derivados de la contaminación. Se evaluó la calidad del aire en siete parques de la ciudad, donde se registró la presencia y la cobertura de líquenes epífitos sobre árboles de Salix humboldtiana. Se determinaron los niveles de contaminación con el Índice de Pureza Atmosférica (IPA) y se establecieron diferencias en la composición de especies de los parques mediante análisis de escalamiento multidimensional no métrico (NMDS) y PERMANOVA. Nuestros resultados mostraron la existencia de una mayor calidad ambiental en las zonas norte y sur de la ciudad, mientras que se observa un patrón contrario para los parques ubicados en la zona central de la urbe, muy relacionados con un aumento de tráfico vehicular. Las comunidades de líquenes epífitos resultaron ser excelentes indicadores biológicos para detectar la contaminación del aire en la ciudad.

Although air pollution constitutes one of the main environmental problems in the city of Loja, there is not currently a strategy for monitoring air pollution emissions. Epiphytic lichens have been widely used as bioindicators of air pollution because they get most nutrients from the air, which makes them very sensitive to changes in pollution levels. Air quality was evaluated in seven parks inside the city, where the presence and coverage of epiphytic lichens on Salix humboldtiana trees were recorded. Pollution levels were determined by the Index of Atmospheric Purity (IAP) and differences in lichen composition were assessed by a non-metric multidimensional scaling (NMDS) analysis and PERMANOVA. Our results demonstrated higher air quality in the northern and southern areas of the city, while on opposite pattern was observed in the parks from the central area of the city likely related to increased vehicular traffic. Epiphytic lichen communities were found to be excellent biological indicators of air pollution in Loja.

As concentrações de diosgenina em uma coleção de tubérculo de Dioscorea polygonoides do Eje Cafetero (EC, Colombia) foram determinadas por cromatografia líquida de alta eficiência. Os teores obtidos variaram de 0,02 a 2,64%. A maior concentração de diosgenina (2,64%) foi obtida de um tubérculo coletado perto de Salento (Quindio). A média de recuperação desta foi de 97%. A identificação foi feita por cromatografia gasosa-espectrometria de massas (CG-EM) e por coeluição com o padrão autentico. Os resultados destes estudos foram importantes uma vez que os teores de diosgenina obtidos se mostraram superiores quando comparados aqueles relatados para outras espécies medicinais de Dioscorea, tornando Dioscorea polygonoides uma fonte potencial de diosgenina.

The diosgenin concentrations in a Dioscorea polygonoides tuber collection from the Eje Cafetero (EC, Colombia) were determined by HPLC and their percentages ranged from 0.02 to 2.64%. The highest diosgenin concentration (2.64%) was obtained in a tuber collected near Salento (Quindío). The average of diosgenin recovery was 97%. Diosgenin was identified by gas chromatography-mass spectrometry (GC-MS) and by coelution with authentic diosgenin standard in both HPLC and GC-MS techniques. The results of this study are important since comparatively they are higher than most of those reported on other medicinal Dioscorea species, making Dioscorea polygonoides a potential new source of diosgenin.