An UPLC-Q-TOF-MS/MS based chemical profiling method was developed to evaluate decocting-induced chemical transformations in Du-Shen-Tang, the decoction of the root of Panax ginseng. Under the optimized UPLC and Q-TOF-MS/MS conditions, over 50 peaks were separated and detected in Du-Shen-Tang within 18 min. The components were identified by comparing the mass spectra and retention time with that of reference compounds, and/or tentatively assigned by elucidating low energy CID fragment ions as well as matching empirical molecular formula with that of the published known compounds. Totally 45 major ginsenosides were identified in Du-Shen-Tang, 21 of which were determined to be newly generated during the decoction of ginseng. The mechanisms involved were further deduced to be hydrolysis, dehydration, decarboxylation and addition reactions of the original ginsenosides in white ginseng through analyzing mimic decoctions of 13 pure reference ginsenosides. Significant difference in chemical profiles between decoctions of two batches of white ginseng suggested that storage duration or other factors significantly influenced the quality consistency of not only the crude drug but also the decoction (Du-Shen-Tang) of white ginseng.
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