Highly selective separation of acteoside from Cistanche tubulosa using an ionic liquid based aqueous two–phase system

To achieve simple and efficient separation of acteoside (ACT), extraction ACT from crude extracts of Cistanche tubulosa via ionic liquid (IL) based aqueous two-phase system (ATPS) is investigated. The IL–ATPS comprising [C 4 mim]BF 4 and (NH 4 ) 2 SO 4 exhibits excellent extraction performance, extracting almost all ACT in the [C 4 mim]BF 4 -rich phase. The high polarity of [C 4 mim]BF 4 having multi-hydrogen bond receptors is conducive for extracting ACT in the IL-rich phase, and (NH 4 ) 2 SO 4 not only provides a weak acidic microenvironment for increasing ACT stability in the IL-rich phase but also reduces the solubility of ACT in the salt-rich phase via the salting-out effect. In addition, molecular simulation results show that ACT is extracted in the [C 4 mim]BF 4 -rich phase via multi-interactions, including hydrogen bonding, van der Waals forces, and π–π stacking. This study is expected to provide a valuable reference for the separation of bioactive constituents from natural products.