Optimization of heat and ultrasound assisted extraction of bioactive compounds from Echinacea purpurea using response surface methodology

Abstract

The optimal conditions for extracting phytochemical from plant materials is a critical step in herbal medicine industry. In the present study, the optimal conditions for extracting the maximum amount of E. purpurea chicoric acid, total phenolics, and antioxidant activity were obtained by response surface methodology (RSM). A D-optimal design of extracting factors including temperature (25–75 °C), sonication time (0–60 min), solvent concentration (0–100%), and solvent types (methanol and ethanol) was generated. Results showed that solvent concentration, solvent types, temperature and sonication times are respectively the most significant factors when all responses were considered. The optimal extraction conditions were found as follows: 75 °C temperature, 51.8 min sonication, and 41.70% methanol with a desirability of 0.982. The optimum condition was repeated five times and the average amount of chicoric acid, total phenolics, and antioxidant activity were 26.09 mg/g, 47.31 mg/g, and 56.94%, respectively, which were in accordance with the optimized predicted values (p < 0.05). In comparison with the optimal conditions obtained in this research, traditional brewing methods cause the loss of more than 50% of bioactive compounds.