Optimization of Ultrasonic-Assisted DES Extraction Process, Kinetics and Antioxidant Activity of Cistanche tubulosa Polyphenols

In order to study the optimal conditions for ultrasonic assisted extraction of polyphenols from Cistanche tubulosa by deep eutectic solvents (DES), the optimal DES (proline:glycerol=2:5) was first selected. Further, response surface methodology (RSM) was used to optimize the extraction processes based on the single factor experiments. The extraction kinetics and antioxidant activity were further studied. The results showed that the optimal conditions were as follows: Ultrasonic temperature of 40 ℃, liquid to solid ratio of 45 mL/g, water content of 40%, extraction time of 28 min. The extraction rate at this condition was 37.76 mg/g DW. Ultrasonic assisted extraction of polyphenols from Cistanche tubulosa conformed to the second-order reaction kinetics. The IC₅₀ values of polyphenol extracts on DPPH and ABTS⁺ free radical scavenging rates were 0.875 and 0.501 mg/mL, respectively. The results would provide a theoretical basis for green extraction and application of polyphenols from Cistanche tubulosa in Xinjiang.