En el proceso de identificar plantas promisorias con actividades hipoglucémicas y antioxidantes, evaluamos las actividades inhibidoras de la α-glucosidasa y la α-amilasa, el contenido fenólico soluble total (TSPC), la actividad de eliminación de radicales libres (DPPH, ABTS) y la capacidad inhibidora de la autooxidación linoleica, de doce plantas utilizadas en la medicina tradicional del Ecuador: Siparuna eggersi (Monte de oso), Croton wagneri (Moshquera), Ilex guayusa (Guayusa), Baccharis genistelloides (Tres filos), Neonelsonia acuminada (Zanahoria blanca), Oreocallis grandiflora (Cucharillo), Verbena litoralis (Verbena), Justicia colorata (Insulina), Artocarpus altilis (Fruto del pan), Adiantun poiretii (Culantrillo), Costus comosus (Caña agria) y Piper crassinervium (Guabiduca). O. grandiflora se encontró superior a las otras plantas, especialmente en términos de su actividad inhibidora sobre α-glucosidasa (IC 50 = 2.8 ± 0.4 μg / mL) y α-amilasa (IC 50 = 161.5 ± 1.3 μg / mL), así como para los radicales libres (DPPH, ABTS) actividad de barrido (IC 50-DPPH = 9.9 ± 0.06 μg / mL; IC 50-TEAC = 6.6 ± 0.55 μg / mL). Por otro lado, A. altilis tuvo la mayor capacidad inhibidora de la autooxidación linoleica (IC 50-β-CLAMS = 3.1 ± 0.20 μg / mL), y O. grandiflora, nuevamente, obtuvo el valor más alto de contenido fenólico soluble total (TSPC = 185.9 ± 0.09 GAE / g extracto). Estos hallazgos sugieren que O. grandiflora podría considerarse como un agente inhibidor y antioxidante enzimático alternativo para el tratamiento de la diabetes mellitus.

Currently, there is great interest in the use of TiO2 for photocatalytic remediation of wastewater. Doping, heterojunction, and immobilization on porous materials are effective methods to improve the photocatalytic efficiency of this semiconductor oxide. In this study, ZnTiO3/TiO2 (ZTO) and ZnTiO3/TiO2/La (ZTO/La) nanocomposites were successfully prepared and immobilized on diatomaceous earth (DE). The composition and texture of the composites prepared were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM-EDX), and specific surface area (SSA). The adsorption capacity and photocatalytic activity of the composites were determined via degradation of methylene blue (MB) in batch reactors. The materials evaluated were prepared in the shape of 0.2 cm (diameter) and 1.0 cm (length) cylindrical extrudates. The results indicate that the ZTO/La-DE composite exhibited higher efficiency for the removal of MB under solar irradiation than both ZTO-DE and DE. The pseudo-second-order model and the Langmuir isotherm model were better suited to explain the adsorption process. The highest degradation percentage of MB obtained was 96% after 150 min of irradiation. The results indicate that synthesized composite could be used for the removal of cationic dyes in wastewater.

Currently, the study of semiconductor materials is very promising for the photocatalytic remediation of hazardous organic substances present in the air and water. Various semiconductors have been investigated in this interesting photo-assisted methodology, among them metal oxides such as ZnO, TiO2 and their derivatives. In this study, ZnTiO3/TiO2 was synthesized by the sol-gel method using Ti(OC3H7)4 and Zn(CH3COO)2 · 2H2O as reagents. The role of several conditions such as synthesis temperature and TiO2:ZnO proportion on the morphology and purity of compounds obtained was studied, and the suitable conditions for the synthesis of photocatalysts were determined. Various techniques were used to conduct a systematic investigation on the structural, morphological, and photocatalytic properties of ZnTiO3/TiO2. Scanning Electron Microscopy (SEM) images show that ZnTiO3/TiO2 have a typical particle size of approximately 100 nm with a quasi-spherical shape. The adsorption and photocatalytic activity were investigated by the decolorization of Methylene Blue (MB) as an organic contaminant under UV irradiation both in TiO2 and ZnTiO3/TiO2 supported over some Ecuadorian clays. The materials evaluated were prepared in the shape of 0.2 cm (diameter) and 1.0 cm (length) cylindrical extrudates. The degradation percentage of MB obtained was 85% approximately after 150 min of irradiation. The results obtained allow us to conclude that these synthesized materials can be used as adsorbents and photocatalysts.

Adsorption is an effective method of removing harmful pollutants from air and water. In the present study, zeolites prepared by sol-gel method from two Ecuadorian clays were combined with precursor clays and the ZnTiO3/TiO2 semiconductor for adsorbing methylene blue (MB) as a water contaminant. The synthesized compounds were characterized using powder X-ray diffraction, X-ray fluorescence, scanning electron microscopy, energy dispersive X-ray, and surface area measurement. These compounds were combined to form cylindrical extrudates of 0.2 cm (diameter) and 1.0 cm (length). The adsorption characteristics of the composites were measured using batch sorption studies as a function of pH, initial concentration, and contact time. The pseudo-second-order model and the Langmuir isotherm model were better suited to the adsorption process. The equilibrium state was achieved around 180 min of adsorption, and a pH of 7 was established as the optimal operating condition. The maximum adsorption values of the dye were obtained with the composites derived from G-Clay, whose average adsorption capacity was 46.36 mg g−1, in contrast with composites derived from R-Clay, whose average adsorption value was 36.24 mg g−1. The results reflect that synthesized composites could be used potentially for the removal of cationic dye from wastewater.