Structural deduction of pregnane glycosides from Dregea sinensis Hemsl by high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry

In the search for novel natural products in the plant, particularly those with potential bioactivity, the MS fragmentation behavior of nine pregnane glycosides previously isolated from Dregea sinensis Hemsl was investigated by electrospray ionization-multistage tandem mass spectrometry (ESI–MSⁿ) equipped with an ion trap analyzer. Furthermore, by high-performance liquid chromtography (HPLC) coupled to ESI–MSⁿ, the thirty-eight unknown pregnane glycosides, combined with six known pregnane glycosides were deduced on the basis of the fragmentation patterns observed from the crude EtOAc extract of D. sinensis Hemsl. This study shows that the HPLC-ESI–MSⁿ is an effective method to rapid and accurate online identification of pregnane glycosides from plant extracts.