Green extraction of cannabidiol from industrial hemp (Cannabis sativa L.) using deep eutectic solvents coupled with further enrichment and recovery by macroporous resin

Deep eutectic solvents (DESs) are good alternatives to conventional organic solvents and ionic liquids (ILs) in the extraction and separation field. In this study, DESs were developed as the media for the green extraction of cannabidiol (CBD) from industrial hemp (Cannabis sativa L). The factors influencing the extraction, including the type and concentration of DESs, solid-liquid ratio, extraction temperature, extraction time, and system pH were investigated in the single factor experiments. Then, the major factors of DESs concentration, solid-liquid ratio, extraction temperature, and extraction time were optimized by response surface methodology (RSM). Under the optimized conditions, the highest extraction yield for CBD was 12.22 mg/g. The Kamlet-Taft polarity parameters were studied to analyze the effect of polarity and hydrogen-bond ability to the extractability of DESs. The extraction kinetics was also studied and the kinetics parameters were analyzed. CBD was further enriched and recovered from the crude extract by macroporous resins, and the recovery yield and the purity reached 81.46% and 28.93%, respectively. This extraction of CBD using DESs has the advantages of high extraction yield, simple operation, low cost and good environmental friendliness, which is potential for the scale-up production. (C) 2019 Elsevier B.V. All rights reserved.