Transformation of astragalosides from Radix Astragali under acidic, neutral, and alkaline extraction conditions monitored by LC-ESI-TOF/MS

To reveal the profile of astragalosides for better quality evaluation of Radix Astragali, this study was aimed to investigate the transformation of astragalosides under different conditions.Seven major astragalosides were selected for evaluation under acidic, neutral and alkaline conditions. The transformation in real plant samples was also examined and the products were characterized by LC-ESI-TOF/MS.In weak acidic solution, all of the astragalosides are stable. In addition, the transformation ratios of the astragalosides under neutral and alkaline conditions were also obtained.In neutral solution, malonylastragaloside I was transformed to astragaloside I; and in alkaline solution, substituent group(s) in the xylose moiety of all the astragalosides were eliminated. Since astragalosdie IV is the basic skeleton structure of the astrgalosides, it is a common transformation product of other astragalosides.