Investigation of the extraction efficiency and antioxidant capacity of deep eutectic solvent-enhanced Paeonia lactiflora

• Design and synthesis of low viscosity, highly soluble and hydrophilic new ternary deep eutectic solvent. • First extraction of polyphenolic active compounds from Paeonia lactiflora . • New ternary deep eutectic solvent with higher extraction efficiency than conventional solvent. • Deep eutectic solvent extracts have higher antioxidant activity and reducing power than traditional solvent extracts. Study has demonstrated that Paeonia lactiflora contains a significant number of polyphenolic compounds; however, there is little research literature focus on phenolic acids in Paeonia lactiflora . In this study, an ultrasound-assisted extraction method based on ternary DESs was developed for the extraction of biologically active polyphenols in Paeonia lactiflora . The results indicated that the ternary solvent composed of choline chloride, DL-lactic acid, and 1,2-propanediol in a molar ratio of 1:4:2 achieved a superior extraction of polyphenols than that of conventional solvents and other ternary solvents. Subsequently, the response surface method was used to optimize the selected parameters of solid–liquid ratio, extraction time, and temperature for the extraction of phenolic by the DES, and the optimal extraction conditions were as follows: a solid–liquid ratio of 1:13.8 g/mL, an extraction time of 47.5 min, and an extraction temperature of 34.5 °C, with a total polyphenol yield of 79.77 mg/g, which is 1.09 times that of the traditional solvent. Furthermore, the extract of Paeonia lactiflora obtained through the DES method exhibited promising in vitro antioxidant activity and reducing ability. Studies have shown that DES is an efficient and environmentally friendly extraction solvent for extracting polyphenols from natural products, providing a new direction for the development and industrial production of Paeonia lactiflora .