Optimization of Ultrasound-Assisted Extraction of Antioxidant from Cirsium setidens Using Response Surface Methodology

Abstract

This study was conducted to optimize the ultrasound-assisted extraction (UAE) conditions for maximizing the responses, including total phenolic compound (TPC), total flavonoid compound (TFC), and radical scavenging activity (RSA) from Cirsium setidens using a response surface methodology (RSM). The following three variables were used to optimize the UAE process using the central composite method: extraction time (X₁: 5.0∼55.0 min), extraction temperature (X₂: 26.0∼94.0°C), and ethanol concentration (X₃: 0.0∼99.5%). The maximum yield of TPC (5.21 mg GAE/g DM), TFC (1.00 mg QE/g DM) and radical scavenging activity (86.7%) were obtained under the optimal conditions of 34.5 min, 63.7°C, and 62.2%. No significant differences were observed between the predicted and experimental values, indicating the suitability of the fitted model and the successful application of CCD. Based on these results, the antioxidant activity of the Cirsium setidens extract can be increased by optimizing the UAE conditions, and the extract can be used as a material for cosmetics, food, and medicine.