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The use of statistical tools in the optimization of bioactive extraction processes increases efficiency and reduces process costs, indicating the optimal conditions for obtaining the best results. The objective of this work was to optimize an ultrasound-assisted extraction procedure and to quantify phenolic compounds in Capsicum frutescens samples. In the optimization of the extraction solution, simplex-centroid mixture design for the proportions optimization of the extractor components (water, methanol, and ethanol) was used. A two-level factorial design (23) was used for the preliminary evaluation of the factors that influenced the extraction process; before this step, a Box-Behnken design was carried out to optimize the factors of solvent volume, sonication time, and temperature with the desirability function as a response. The best mixture composition was 95% methanol and 5% water and the best experimental conditions for the process variables were 16 mL, 15 min, and 55 °C. Applying the method to pepper samples, twelve compounds were determined by HPLC–DAD. The relative standard deviations (RSD) found for all analytes were lower than 3.0%. The accuracy was evaluated using addition/recovery test with recoveries between 81 and 95%. The Box-Behnken and mixture designs are efficient tools for optimizing the analytical method using ultrasound to extract phenolic compounds from C. frutescens. The procedure was applied for extraction phenolics compounds in three papers samples and the concentrations found were trans-cinnamic acid (

Physalis angulata is a medicinal plant with potential to treat several diseases due to the presence of secondary metabolites, such as phenolic compounds. The influence of the application of different abscisic acid (ABA) concentrations on the composition of phenolic compounds and gas exchange was evaluated on the Physalis angulata leaves. The experiment was conducted in a greenhouse in Cruz das Almas, Bahia, Brazil, with potted plants. At 45 days after sowing, the plants were separated into groups and the following treatments were applied: 0, 25, 50, 100 and 150 μmol L−1 of ABA. Two days after the treatments application, the gas leaf exchange (liquid photosynthesis, stomatal conductance, transpiration rate, mesophilic CO2 concentration and the relationship between atmospheric CO2 concentration and mesophilic CO2 concentration) between 9:00 and 11:00 was measured using an infrared gas analizer (IRGA). Four days after ABA spraying, some plants showed senescence symptoms, and therefore they were collected and taken to the stove until reached a constant dry mass. The total phenolics, caffeic acid, rutin, and trans-cinnamic were evaluated in response to the ABA. The ABA application increased the synthesis of total phenolic compounds up to 50 μmol L−1 concentration. The ABA application did not interfere with the caffeic acid synthesis. However, the rutin concentration increased regardless of ABA concentration that was applied and for trans-cinnamic acid, there was an increase up to the concentration of 100 μmol L−1. The ABA application caused stomatal closure and, consequently, the leaf gas exchange of Physalis angulata reduced.

The present article describes the development of an ultrasonic assisted extraction of phenolic compounds in Physalis angulata and determination of caffeic acid, rutin, catechin and trans-cinnamic acid by HPLC DAD. The mixtures were composed of extractor solvent and its ratio optimized using a mixture design. Doehlert matrix was used to optimize the extractor solvent volume and sonication time while using total phenolics as analytical response. The optimized conditions for the extractor solvent were the ratio of: 57% water, 35% ethanol and 8% methanol. The best experimental conditions for ultrasound were a sonication time of 10 min and extractor volume of 15 mL. The limit of detection varied from 5.0 to 30 μg L−1. The methods precision was expressed as relative standard deviation (RSD) and presented values lower than 3.0% for all analytes. The accuracy was evaluated using spike test with recoveries between 91% and 107%. The method was applied for the determination of caffeic acid, rutin, catechin and trans-cinnamic in four samples of Physalis angulata aerial parts and the concentration varied from 15.5 to 22.5 μg g−1 for catechin, from 25.0 to 32.5 μg g−1 for caffeic acid, 75.6 to 88.2 μg g−1 for rutin and varied from 23.5 to 110.7 μg g−1 for trans-cinnamic acid.

The chili pepper is highly valued for its pungency and nutritional value, in addition to being a good source of phenolic compounds. Several factors affect the production of phenolics in the plant, including plant regulators. In this context, the present work aims to evaluate the influence of ABA, GA3, and SA in the production of phenolic compounds in Capsicum frutescens. It was applied 10 mmol L−1 of ABA, 144 mmol L−1 of GA3, 2000 mmol L of SA−1 and the control (C) (solution without regulators) in fruits of C. frutescens. The results show that chili pepper presented a good variety of phenolics, ranging from phenolic acids (benzoic and cinnamic acids) to flavonoids (flavonols and flavan-3-ols) and that phenolic concentrations were significantly altered in fruits treated with GA3, ABA and SA compared to control fruits. In addition, the PCA and HCA separated the samples into three groups, C, ABA, and a group with GA3 and SA, with the ABA group having the highest phenolic content and the C group the lowest. Plant regulators (GA3, ABA and SA) influence the synthesis of phenolic compounds in C. frutescens fruits.