Determination of the transformation of ginsenosides in Ginseng Radix et Rhizoma during decoction with water using ultra-fast liquid chromatography coupled with tandem mass spectrometry

This study was conducted to determine the variations of ginsenosides in Ginseng Radix et Rhizoma when using different preparation solvents and explore the major factors for changes. With an established ultra-fast liquid chromatography coupled with tandem mass spectrometry method which could quantify 52 ginsenosides, the extraction differences were characterized and compared using different solvents (water, 70% aqueous ethanol, and ethanol). Subsequently, a series of aqueous solutions with different pH were prepared to test the influence of pH to the changes of ginsenosides. Meanwhile, acetic acid and aspartic acid were used to verify whether the reaction had a relationship with the kind of acids. After refluxing with water, not only highly polar ginsenosides were extracted, some less polar ginsenosides such as ginsenoside Rg(3), Rg(5), Rk(1), and Rh-2 occurred or increased rapidly. Further experiments indicated that less polar ginsenosides were easier to generate at low pH values, and the reaction was only related to pH other than what kind of acids were used. It is the first time to elaborate the contents variation of 52 ginsenosides when using different extraction methods. The results indicated that decoction with water could enhance the transformation of highly polar ginsenosides to less polar ginsenosides and the process was pH dependent.