Optimization of Ultrasound Assisted Extraction (UAE) of Kinsenoside Compound from Anoectochilus roxburghii (Wall.) Lindl by Response Surface Methodology (RSM)

The purpose of this study was to establish an extraction method for the kinsenoside compound from the whole plant Anoectochilus roxburghii. Ultrasound assisted extraction (UAE) and Ultra-high performance liquid chromatography (UPLC) method were used to extract and determine the content of kinsenoside, while response surface method (RSM) was used to optimize the extraction process. The best possible range for methanol concentration (0−100%), the liquid-solid ratio (5:1−30:1 mL/g), ultrasonic power (240−540 W), duration of ultrasound (10−50 min), ultrasonic temperature (10−60 °C), and the number of extractions (1−4) were obtained according to the single factor experiments. Then, using the Box-Behnken design (BBD) of response surface analysis, the optimum extraction conditions were obtained with 16.33% methanol concentration, the liquid-solid ratio of 10.83:1 mL/g and 35.00 °C ultrasonic temperature. Under these conditions, kinsenoside extraction yield reached 32.24% dry weight. The best conditions were applied to determine the kinsenoside content in seven different cultivation ages in Anoectochilus roxburghii.