Purification of honokiol derivatives from one-pot synthesis by high-performance counter-current chromatography

This paper describes the application of high-performance counter-current chromatography (HPCCC) as a fast, useful and economic alternative for the separation and purification of seven honokiol derivatives (two of them are isomers), which were synthesized by a one-pot procedure. Five honokiol derivatives were successfully separated by n-hexane-ethyl acetate-methanol-water solvent system at three different volume ratios in a step-gradient elution. Two derivatives were obtained through a cycle elution mode. The whole separation process produced 366.3 mg, 323.6 mg, 242.8 mg, 216.2 mg, 203.5 mg, 185.8 mg and 279.3 mg of 3'-formylhonokiol (1), 2'-methoxy-3'-formylhonokiol (2), 2'-methoxyhonokiol (3), 4-methoxyhonokiol (4), 3',5-diformylhonokiol (5), 2',4-dimethoxy-3'-formylhonokiol (6) and 2',4-dimethoxyhonokiol (7) from crude sample of 3 g with purities of 98.7%, 99.3%, 98.6%, 98.2%, 99.0%, 98.4% and 99.2%, respectively. The purities and structural identification were determined by HPLC, (1)H NMR, (13)C NMR and mass spectroscopy.