Ultrasonic-Microwave Assisted Extraction of Total Flavonoids from Scutellaria baicalensis Using Response Surface Methodology

Ultrasonic-microwave assisted extraction (UMAE) was employed to extract total flavonoids (TF) from Scutellaria baicalensis roots. Single-factor experiments to evaluate effects of the process parameters (solvent-to-material ratio, ethanol concentration, extraction time, ultrasonic power, microwave power, and extraction temperature) on the TF yield were performed, and the response surface methodology (RSM) was used to optimize the extraction parameters. The optimum conditions to obtain the maximum TF yield were as follows: solvent-to-material ratio, 24; ethanol concentration, 52%; extraction time, 15.0 min; extraction temperature, 62.0A degrees C; ultrasonic power and microwave power, 300 W each. The TF yield under these conditions reached 8.71 +/- 0.26%. The analysis of variance and validation test indicated that the proposed method is useful and reliable.