Ultrasonic-assisted DES extraction optimization, characterization, antioxidant and in silico study of polysaccharides from Angelica dahurica Radix

Abstract

In this study, polysaccharides from Angelica dahurica Radix (ADR) were extracted by using ultrasonic-assisted deep eutectic solvent (DES) extraction method. The DES consist of choline chloride (HBA, hydrogen bonding acceptor) and 1, 4-butanediol (HBD, hydrogen bonding donor) with the molar ratio of 1:3 was proved as the best system for polysaccharides extraction. A Box-Behnken design with three factors and three levels was utilized to optimize ultrasonic power, extraction time and temperature for increased polysaccharides yield. The optimal extraction parameters were determined as follows: DES water content of 20 %, liquid–solid ratio of 10:1 mL/g, ultrasonic time of 21 min, temperature at 60 °C, and ultrasonic power of 435 W. These conditions yielded an extraction rate nearly matching the theoretical predicted value of the response surface model, surpassing the traditional hot water extraction method by 1.33 times and requiring less time. The antioxidant polysaccharides was assessed using DPPH, ABTS and Hydroxyl methods, which indicated that ADRP extracted by ultrasound assisted DES had excellent antioxidant capacity and showed a dose–response relationship with drug concentration. Structural analysis identified ADR polysaccharides as a heteropolysaccharide rich in sugar aldonic acids—namely, fucose, rhamnose, arabinose, galactose and glucose—with molar ratios of 0.47:1.99:17.61:64.76:15.17. The polysaccharides’ number-average molecular weight was determined to be 97.422 kDa, with a weight-average molecular weight of 245.678 kDa. Network pharmacology and molecular docking analysis suggest that the monosaccharides Rha and Ara could potentially interact with the proteins GSR and GSTA1, respectively, indicating that ADRP had good antioxidant potential and could be applied in multiple fields with promising development prospects in the future.

Keywords

• Deep eutectic solvents
• Angelica dahurica Radix
• Polysaccharides
• Ultrasonic-assisted extraction
• Response surface methodology
• Network pharmacology