A study of the roots of Astragalus mongholicus and Astragalus membranaceus by high performance liquid chromatography-mass spectrometry

High performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESIMS) has been applied to analyze the chemical constituents of Radix Astragali, the roots of Astragalus mongholicus and Astragalus membranaccus. HPLC column: Inertsil ODS-3 C-18; Elution: acetonitrile-water with gradients; Flow rate: 1.0 mL/min; Detector: ultraviolet (UV) and ESI-MS. Fourteen components were identified as calycosin-7-O-beta-D-glueopyranoside (1), ononin (2), 9,10-dimethoxyptero-carpan-3-O-beta-D-glucopyranoside (3), 2'-bydroxy-3',4'-dimethoxyptero-carpan-7-O-beta-D- glueopyranoside (4), claycosin (5), astragaloside IV (6), astragaloside R (7), isoastragaloside II (8), formononetin (9), astragaloside I (10), isoastragaloside I (11), sucrose (12), calycosin-7-O-beta-D-glueopyranoside-6"-O-malonate (13) and acetylastragaloside I (14) by direct comparison with the isolated standards, the ESI-MSn, and UV spectra. By comparison, it is found that most of the components were similar except for some minor differences in the two species. The proposed fragmentation pathways of the major components are given.