Mixture design and Doehlert matrix for optimization of the ultrasonic assisted extraction of caffeic acid, rutin, catechin and trans-cinnamic acid in Physalis angulata L. and determination by HPLC DAD

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.