Mechanism of deep eutectic solvents based extraction of phenolic and flavonoid compounds from peony petals

Deep eutectic solvents (DES) have exhibited great potential in the extraction of active ingredients from flowers. In this study, ternary DESs were designed for the extraction of phenolic and flavonoid compounds from peony petals. When the molar ratio of ChCl:EG:U was 1:2:2, and the water content was 30 %, the maximum extraction yields of total phenolic content (TPC) and total flavonoid content (TFC) were achieved, reaching 109.30 mg GAE/g and 56.93 mg RE/g, respectively. Meanwhile, cellulose nanofibers were prepared. The relationship model with extraction yield as the target was established by multivariate analysis. The model indicated that the property parameters of the HBD had a significant impact on the extraction yields of TPC and TFC. At the molecular level, Density functional theory (DFT) was employed to explore the extraction mechanism. The analysis revealed that hydrogen bonding was the main interaction force. The maximum binding energy between DES and rutin was −89.03 kcal/mol. This study provides an efficient extraction solvent and insights into the mechanism of extracting the phenolic and flavonoid compounds from peony petals.