Extraction of glabridin using imidazolium-based ionic liquids

The present study aims to extract bioactive glabridin from licorice extract using imidazolium-based ionic liquids (ILs). A series of 1-alkyl-3-methylimidazolium ionic liquids with different anions and alkyl chain lengths of cations were selected to extract glabridin. The results are as follows: IL anions have a significant effect on the extraction efficiency of glabridin, the alkyl chain length of imidazolium cations has a minor effect on the extraction efficiency of glabridin, and IL with [NTf2]− anion and [C6mim]+ cation achieve better performances. Under optimal conditions of glabridin extraction technology, a glabridin distribution ratio of 72.67 was achieved with [C6mim][NTf2]. The results show that during the extraction, the interactions between IL and glabridin were mainly based on hydrogen-bonding interactions and the hydrophobic interactions.

► Ionic liquids with different anions and alkyl chain lengths of cations were screened.
► A glabridin distribution ratio of 72.67 was achieved with [C6mim][NTf2].
► The extraction of glabridin was greatly affected by ionic liquid anions.
► The interactions mainly based on hydrogen-bonding and the hydrophobic interactions.