The present study carried out the optimisation of the total polyphenol content (TPC) extraction assisted by ultrasound in Ilex guayusa leaves applying response surface methodology (RSM). Also, the evaluation of the antioxidant activity of the extract obtained under the optimal extraction conditions was performed. The effect of the variables like, time of sonication, temperature, ethanol/water ratio and solid/liquid relationship and the interactions between them were analysed through the use of a factorial design 2^4. The significant factors were considered for the optimisation, employing a Box-Behnken Design, and the TPC as response variables. It was found that a quadratic model was adequate, with an adjusted R 2 value of 0.9367. The optimal conditions proposed, by the response surface model were: an extraction temperature of 60 C, sonication time of 29.9 min and ethanol/water ratio of 76.8/23.2. The optimised leaves extract of I. guayusa show a TPC of 3.46 (AE0.17) g gallic acid equivalents/100 g d.w. Radical scavenger activity of the obtained extract at optimum conditions, was performed through the FRAP and ABTS methods, given as result: 0.080 mmol TROLOX equivalents/100 g d.w. and 40.71 μmol TROLOX equivalents/g d.w., respectively. Due to the present findings, I. guayusa extracts can be proposed as a promising component for functional beverages, cosmetic and pharmaceutical formulation.

Essential oils (EOs) are known for their antioxidant properties, and are widely employed in the food industry as preservatives. They can be used as condiments or as preservatives to achieve certain organoleptic effects for consumers. The aim of this research was to evaluate antioxidant activity in mixtures of three EOs: Apium graveolens L. , Thymus vulgaris L. and Coriandrum sativum L., using the Simplex Lattice Mixture Design. Ultimately, a linear model was used, as it best adjusted to the experimental behavior, and it allowed the prediction of EOs mixtures antioxidant activity, determined by FRAP and ABTS techniques. The mixture of the three EOs that showed the best antioxidant activity and also had the highest synergistic effect, was composed of 66.7% of T. vulgaris , 16.7% of C. sativum and 16.7% of A. graveolens . The greatest contribution to the potentiation of antioxidant activity was shown by T. vulgaris followed by A. graveolens and then C. sativum .

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Few studies have comprehensively evaluated the effect of changing land use on the soil quality in the Ecuadorian Amazon region that is subject to continued deforestation processes. This study evaluated the influence of different types of land use on soil quality using an integrated soil quality index (SQI) with a minimum set of indicators, based on 140 soil samples from 7 land use types, in seven productive distinct landscapes in Pastaza Province, Ecuador. The land use type evaluated was Chakra_A, Chakra_B, Chakra_C, Cattle_A, Cattle_B, Cattle_C, and Forest. Land use type had significant effects on soil properties and thus on soil quality. SQI was developed by using, AP, Zn, TOC, BD, and LL; AP and Zn had highest weighting values (0.38), which indicated that these indicators contributed the most to final SQI. In general, the SQI varied significantly depending on the type of land use and two groups were established: the first categorized as of moderate quality with mean SQI values of 0.45, 0.44, and 0.41 for Chakra_A, Forest and Chakra_B, respectively; while the second group registered average SQI values of 0.33, 0.33, 0.32, and 0.30 for Chakra_C, Cattle_C, Cattle_A and Cattle_B, respectively, considered of low quality. The methods used are applicable to the study of changes in soil properties as functions of agroforestry systems, which are generated by changes in land use in similar landscape of the Ecuadorian Amazon.

Se evaluó la biomasa aérea acumulada en lo concerniente a familias botánicas en un bosque siempreverde piemontano sometido a diferentes grados de intervención en la zona alta de la microcuenca del río Puyo. En cinco transectos de 0.1 ha se registraron las especies con DAP ≥ 10 cm. Se encontró menor número de familias en sitios con alto grado de perturbación. La biomasa aérea varió de 161.84 a 339.70 Mg.ha-1, presentándose mayor acumulación en individuos de menor clase diamétrica. Las familias con mayor índice de valor de importancia de biomasa fueron Moraceae, Arecaceae y Euphorbiaceae, reconocidas por su potencial en cuanto a estructura y carbono. El análisis de correspondencia canónica sin tendencia (DCA) indicó variación en la contribución de biomasa para cada sitio, existiendo un pequeño número de familias para mantener las reservas de carbono. Los resultados de este estudio brindan información relevante que facilita la toma de decisiones con respecto la restauración de sitios perturbados.