A novel and green temperature-responsive biphasic deep eutectic solvent-based system for simultaneous extraction and pre-separation of active ingredients from Zanthoxylum bungeanum Maxim. peels

In the current work, a temperature-responsive system consisting of a fatty acid-based hydrophobic deep eutectic solvent and a choline chloride (ChCl)-based hydrophilic deep eutectic solvent was innovatively developed. It was used to extract and separate polar compounds (chlorogenic acid, rutin, hyperin, isoquercetin, hydroxy-α-sanshool) from Zanthoxylum bungeanum Maxim. peels (ZBMP). Different molar ratios of the hydrophobic deep eutectic solvent (DES) composed of decanoic acid (DA)-octanoic acid (OA) and hydrophilic DES composed of ChCl-levulinic acid (Lev) were chosen as the switching medium. Under the optimal extraction conditions, the TRBDES consisting of hydrophilic DES (ChCl: Lev/1:2): hydrophobic DES (OA: DA/2:1): H 2 O (v/v/v,5/5/1) demonstrated a greater total extraction rate and distributive efficiency than the conventional solvents. High DPPH radical scavenging capacity of target compounds (IC 50 = 0.29 mg/mL) from the bottom phase recovered by D101 macroporous resin. Hydrogels prepared by DES containing extracts in the top phase showed significant inhibition of E. coli (15.5 ± 0.7 mm). and S. aureus (21.0 ±1.4 mm). The solvent morphologies and the intrinsic switching mechanism were observed and illustrated. Moreover, density functional theory (DFT) calculations showed that hydrogen bond production is crucial for extraction. This work provides a resource for exploring and utilizing TRBDES for environmentally friendly extraction of various bioactive active ingredients from plant sources.