*Article* **DES Based Efficient Extraction Method for Bioactive Coumarins from** *Angelica dahurica (Hoffm.) Benth. & Hook.f. ex Franch. & Sav.*

**Ting Wang and Qian Li \***

Gansu Provincial Key Laboratory of Aridland Crop Science, College of Agronomy, Gansu Agricultural University, Lanzhou 730070, China; wangting2021echo@163.com

**\*** Correspondence: liqian1984@gsau.edu.cn

**Abstract:** In this study, a simple and environmentally friendly method was developed for the extraction of seven active coumarins from *Angelica dahurica (Hoffm.) Benth. & Hook.f. ex Franch. & Sav. (A. dahurica)* based on deep eutectic solvents (DESs). Among the 16 kinds of DES based on choline chloride, the DES system with the molar ratio of choline chloride, citric acid, and water as 1:1:2 had the best extraction effect. Ultrasonic-assisted response surface methodology (RSM) was used to investigate the optimal extraction scheme. The results showed that the optimal extraction conditions were a liquid–solid ratio of 10:1 (mL/g), an extraction time of 50 min, an extraction temperature of 59.85 ◦C, and a moisture content of 49.28%. Under these conditions, the extraction yield reached 1.18%. In addition, scanning electron microscopy (SEM) was used to observe the degree of powder fragmentation before and after extraction with different solvents. The cells of *A. dahurica* medicinal materials obtained by DES ultrasonic-assisted treatment were the most seriously broken, indicating that DES had the highest efficiency in the treatment of *A. dahurica*. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) DPPH radical scavenging model was used to evaluate the biological activity of DES extract. The results showed that DES extract had better scavenging ability of DPPH free radical. Therefore, DES is a green solvent suitable for extracting coumarin compounds of *A. dahurica*, with great potential to replace organic solvents.

**Keywords:** deep eutectic solvents; *Angelicae dahuricae*; coumarins; response surface methodology
