Comprehensive separation and analysis of alkaloids from Stephania yunnanensis by counter-current chromatography coupled with liquid chromatography tandem mass spectrometry analysis

The polar compounds such as alkaloid compounds are important bioactive components in traditional Chinese medicines. In present study, a comprehensive method for separation and analysis of polar compounds from the polar fraction of traditional Chinese medicine Stephania yunnanensis was established. Both the major components and minor components were analyzed by counter-current chromatography combined with liquid chromatography tandem mass spectrometry (LC–MSn). From 50 mg polar fraction of crude extract, 15.2 mg corydine and 4.8 mg stepharine with purities over 90% were successfully separated via a polar solvent system n-butanol: methanol: water (4:1:5, v/v) with 10 mM NaOH as an additive in the lower phase, in one step operation. Their structures were further identified by 1H NMR and FTICR–MS. Besides, three minor components were identified by HPLC–MSn based on the fragmentation behavior of the purified compounds.