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

AIM: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.METHOD: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.RESULTS: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.CONCLUSION: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.