Alkaloid Extraction from Coptis chinensis Franch. Using Ultrasound-Assisted Aqueous Solutions of Surfactants, Organic Acids, Deep Eutectic Solvents, and Supramolecular Deep Eutectic Solvents

Berberine, palmatine, and coptisine are bioactive alkaloids commonly found in medicinal plants, including <i>Coptis chinensis</i> Franch. (Ranunculaceae). To address the limitations of conventional volatile organic solvents, this study employed eco-friendly solvents-aqueous solutions of surfactants, carboxylic acids, and deep eutectic solvents-to extract these alkaloids. Among the solvents tested, lactic acid, malic acid, and pyruvic acid exhibited the highest extraction efficiencies. Optimal extraction conditions for ultrasound-assisted extraction were determined via response surface methodology. For lactic acid, optimal conditions included a concentration of 96% (<i>w</i>/<i>w</i>), a liquid-to-solid ratio of 30.0 mL/g, and a temperature of 60.0 °C, yielding 139.6 ± 0.2 mg/g of total alkaloids. Malic acid at 40.0% (<i>w</i>/<i>w</i>), 30.0 mL/g, and 80.0 °C produced 133.0 ± 0.5 mg/g, while pyruvic acid at 88.0% (<i>w</i>/<i>w</i>), 30.0 mL/g, and 75.0 °C resulted in 146.3 ± 0.4 mg/g. The recovery efficiencies of these alkaloids were further enhanced using macroporous resins. The XAD-8 and AB-8 resins achieved recovery rates of 80.11 ± 0.78% and 79.00 ± 1.06%, respectively, for lactic acid extracts. The LSA-40 resin yielded efficiencies of 95.58 ± 1.40% and 89.86 ± 0.90% for malic and pyruvic acid extracts, respectively. Notably, the combination of malic acid as an extraction solvent and the HPD-400 resin achieved an impressive alkaloid recovery yield of 79.52% from <i>C. chinensis</i>. This work represents the first reported application of this approach and highlights the potential of green solvents and macroporous resins for sustainable and efficient alkaloid extraction from <i>C. chinensis</i>.