Preparative high-performance liquid chromatography for the purification of natural acylated anthocyanins from red radish (Raphanus sativus L.).

Preparative high-performance liquid chromatography (HPLC) is applied to the purification of anthocyanins from raw extracts of red radish (Raphanus sativus L). For each separation, the chromatographic conditions are optimized to achieve an efficient purification in the shortest time. In addition, UV-vis characterization is carried out on all purified anthocyanins. The current work shows that analytical chromatographic experiments alone are useful for the prediction of scale-up conditions of preparative HPLC separations. Ten known acylated anthocyanins (See the Appendix for compounds 1-10) are isolated from the red radish by isocratic HPLC. The structures are established on the basis of nuclear magnetic resonance and mass spectrometric analysis. The acylated anthocyanins are all based on pelargonidin 3-sophoroside-5-glucoside, acylated with caffeoyl, feruloyl, or p-coumaroyl moieties.