Separation of polyphenols from leaves of Malus hupehensis (Pamp.) Rehder by off-line two-dimensional High Speed Counter-Current Chromatography combined with recycling elution mode

In this study, off-line two-dimensional High Speed Counter-Current Chromatography (2D HSCCC) strategy combined with recycling elution mode was developed to isolate compounds from the ethyl acetate extract of a common green tea - leaves of Malus hupehensis (Pamp.) Rehder. In the orthogonal separation system, a conventional HSCCC was employed for the first dimension and two recycling HSCCCs were used for the second in parallel. Using a solvent system consisting of n-hexane-ethyl acetate-methanol-water (1:4:0.6:4.4, v/v) in the first and second dimension, four compounds including 3-hydroxy-phlorizin (1), phloretin (2), avicularin (3) and kaempferol 3-O-β-d-glucoside (4) were obtained. The purities of these four compounds were all over 95.0% as determined by HPLC. And their structures were all identified through UV, MS and 1H NMR. It has been demonstrated that the combination of off-line 2D HSCCC with recycling elution mode is an efficient technique to isolate compounds with similar polarities in natural products.