Extraction of Alkaloids from Coptidis Rhizoma via Betaine-Based Deep Eutectic Solvents

To avoid the use of volatile organic compounds, a series of betaine-based deep eutectic solvents (DESs), which are considered as green solvents, were prepared for the efficient extraction of alkaloids from coptidis rhizome. The extraction conditions were optimized via response surface methodology (RSM) to achieve the maximum recovery of total alkaloids. A central composite design with three independent variables which included the concentration of the selected DES, extraction time, and solvent/solid ratio at five levels, was applied while response surface plots were produced with a second order polynomial model. A one-off experiment was performed to examine the reliability of the simulated results obtained from RSM. An optimized yield of 128.43 mg/g was obtained at an extraction time of 29.5 min and a solvent/solid ratio of 35 : 1 with the extraction solvent as 0.6 M betaine-tartaric acid- water DES.