Optimization of Ultrasonic-assisted Extraction of Phenylethanoside from Cistanche tubulosa and Its Antioxidant Activities

In order to optimize the ultrasonic-assisted extraction process of phenylethanol glycosides from Cistanche tubulosa (Ct) in Xinjiang, box-behnken design was used to optimize the extraction conditions based on single factor experiments. Optimal conditions were the temperature of 40 ℃, the solid-liquid ratio of 1:41.7 g/mL and the ethanol concentration of 51%. The extraction yield under the optimal conditions was (14.36±0.12) mg/g. The extracts were mainly composed of echinacoside and verbascoside, the contents of which were (12.96±0.33) mg/g and (1.19±0.09) mg/g, respectively. The phenylethanoside extracts showed strong scavenging ability to hydroxyl radical and DPPH free radical, and the semi-inhibitory concentration (IC₅₀) values were 60.196 mg/mL and 0.875 mg/mL, respectively. This study provides basic data for the extraction of phenylethanoside from Cistanche tubulosa in Xinjiang.