Advancing green extraction of bioactive compounds using deep eutectic solvent-based ultrasound-assisted matrix solid-phase dispersion: Application to UHPLC-PAD analysis of alkaloids and organic acids in Coptidis rhizoma

The utilization of deep eutectic solvents (DES) in sustainable extracting and separating of phytochemicals shows promising prospect. An exceptionally fast, eco-friendly, and sustainable approach was proposed for extracting bioactive compounds from Coptidis Rhizoma based on deep eutectic solvent-based ultrasound-assisted matrix solid phase dispersion (DES-UAMSPD). Single-factor experiments and Box-Behnken design were utilized to explore the optimal extraction conditions. The analysis indicated that the acidic DES, especially betaine-acrylic acid (Bet-Aa 1:4 mol/mol) with 50% water content, was proved to be the most effective medium for the extraction of alkaloids (magnoflorine, groenlandicine, coptisine, epiberberine, berberine and palmatine) and organic acid (chlorogenic acid). With the parameters optimized, the total maximum extraction yield of alkaloids and organic acids reached 128.83 mg·g−1 applying the optimal DES, which was 1.33–5.33 folds higher than conventional extraction solvents. Additionally, through microstructure analysis using scanning electron microscopy (SEM), density functional theory (DFT), and frontier molecular orbitals theory, a deeper understanding of the extraction principle was gained, and the molecular mechanism of DES synthesis and the interactions between target compounds were systematically elucidated. The sustainable and green potential of the DES-UAMSPD method was demonstrated through Green Analytical Procedure Index (GAPI) analysis. The overall results of this investigation revealed that the proposed technology was a highly promising and sustainable alternative for effective extraction and quantification of natural products.