A countercurrent chromatography solvent system based on deep eutectic solvents for separation of cis- and trans-crocetin from Gardenia jasminoides Ellis.

Due to the structural similarity and large difference in concentration, the separation of trans- and cis-crocetin has been challenging, and the cis-crocetin is usually neglected. In this work, a countercurrent chromatography method was developed for the quick separation of trans-crocetin and cis-crocetin from the hydrolytic extract of Gardenia jasminoides Ellis. High purity of trans-crocetin (>95%) and cis-crocetin (>91%) were prepared simultaneously for the first time through a novel biphasic system based on deep eutectic solvents, n-heptane/n-butyl alcohol/13 mmol/L Na CO in water/acetamide-benzyltrimethylammonium chloride (4:1, mol/mol) (4:7:9:1, v/v). The addition of deep eutectic solvent significantly improved the separation efficiency. The two targets can be easily recovered from the separation system through simple acidification and precipitation. It has potential for preparative separations on a large scale.