Among the most critical needs of natural product chemistry is a complete library of pure reference substances. Some khellactone-type isomers of pharmacological importance are either still lacking reference substances or references are only available in limited amounts. To address this need, a recycling high-performance liquid chromatography (R-HPLC) strategy was adopted to improve the isomer separation efficiency from Peucedanum japonicum. Under the optimal isolation conditions, we obtained isomerically pure substances, particularly khellactone coumarins with different substituent groups. Isolated compounds attained purities greater than 98% as determined by ultra-performance liquid chromatography-charged aerosol detector (UPLC-CAD) and photodiode array (PDA). The structures of these compounds were identified according to their mass patterns and 2D NMR spectra. The proposed methods of single-column recycling obtained the same amount of product as conventional systems while being simple, increasing efficiency and reducing cost.
Keywords: Khellactone coumarins; Peucedanum japonicum; Recycling HPLC; Reference substances.
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