Chemical Differentiation of Two Taste Variants of Gynostemma pentaphyllum by Using UPLC–Q-TOF-MS and HPLC–ELSD

To differentiate the sweet and bitter taste variants of a Chinese medicinal tea Gynostemma pentaphyllum (GP), a method for the quantitative analysis of ginsenosides Rb1, Rb3, Rd, and F2 in GP by using UPLC–Q-TOF-MS was developed. According to the different contents of the four ginsenosides, chemical differentiation of the two taste variants of GP was achieved by principal component analysis (PCA). A supplementary quantitative analysis method of using HPLC–ELSD for determination of 20(S)-panaxadiol in the hydrolysates of GP was also developed. Similarly, chemical differentiation based on different amounts of 20(S)-panaxadiol was established and the result was well consistent with that based on the analysis of the four ginsenosides. It was found that the amounts of the four ginsenosides and 20(S)-panaxadiol in the sweet taste variant were significantly higher than those in the bitter one. The significant difference between the sweet and bitter taste variants of GP was easily visualized in 3D-PCA score plots. The PCA loading plot also indicated the contributions among the four ginsenosides (Rd > Rb3 > F2 > Rb1) for distinguishing the two taste variants. This is the first report to describe the use of these two quantitative methods (UPLC–Q-TOF-MS and HPLC–ELSD) for the accurate authentication and quality control of GP.