Process optimization and antioxidant activity of white peony root components extracted via ultrasound-assisted deep eutectic solvents

The study aimed to extract antioxidant-rich components from white peony root (WPR) using the ultrasound-assisted deep eutectic solvents (UAE-DES) and optimizing them through response surface methodology to enhance their antioxidant potential. Twenty DESs and three conventional solvents were evaluated, and choline bromide-formic acid (DES17) was found best among them for extracting antioxidant components from WPR. The UAE-DES process was optimized using the Box-Behnken response surface method, achieving a maximum yield (18.16 ± 0.67 mg/g) under optimal conditions (41 min, 1:40 g/mL, and 58 % DES/H₂O), with an extraction efficiency 4-13 times higher than traditional techniques. The study also evaluated the significant DES reusability and recovery of antioxidant components using macroporous resins. Additionally, the DES-derived optimized WPR extract demonstrated significant in vitro antioxidant activity. FTIR, ¹H NMR, SEM, and DFT calculations were carried out to better understand chemical component interactions and extraction mechanisms. This study advances green solvent chemistry and ultrasound applications in natural product processing by providing a viable, environmentally friendly method for the quick and effective extraction of important phytochemicals from plant matrices.