Remarkable impact of steam temperature on ginsenosides transformation from fresh ginseng to red ginseng

Abstract

Background: Temperature is an essential condition in red ginseng processing. The pharmacological activities of red ginseng under different steam temperatures are significantly different.

Methods: In this study, an ultrahigh-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry was developed to distinguish the red ginseng products that were steamed at high and low temperatures. Multivariate statistical analyses such as principal component analysis and supervised orthogonal partial least squared discrimination analysis were used to determine the influential components of the different samples.

Results: The results showed that different steamed red ginseng samples can be identified, and the characteristic components were 20-gluco-ginsenoside Rf, ginsenoside Re, ginsenoside Rg1, and malonyl-ginsenoside Rb1 in red ginseng steamed at low temperature. Meanwhile, the characteristic components in red ginseng steamed at high temperature were 20R-ginsenoside Rs3 and ginsenoside Rs4. Polar ginsenosides were abundant in red ginseng steamed at low temperature, whereas higher levels of less polar ginsenosides were detected in red ginseng steamed at high temperature.

Conclusion: This study makes the first time that differences between red ginseng steamed under different temperatures and their ginsenosides transformation have been observed systematically at the chemistry level. The results suggested that the identified chemical markers can be used to illustrate the transformation of ginsenosides in red ginseng processing.

Keywords: MVA; UPLC–QTOF-MS/MS; red ginseng; steaming temperature; transformation.

Fig. 1

Representative base peak intensity chromatograms of red ginseng samples. (A) Red ginseng (HH). (B) Red ginseng (HL). ES-, negative electrospray ionization; HH, high temperature; HL, low temperature; neg, negative; TIC, total ion chromatography; TOF MS, time-of-flight mass spectrometry.

Fig. 2

The PCA of red ginseng at different steaming temperature. PCA, principal component analysis; HH, high temperature; HL, low temperature; NEG: negative ion model.

Fig. 3

The S-Plot of red ginseng at different steaming temperature. 1 ion (t_R = 5.58 min, m/z 1,077.5450), 2 ion (t_R = 6.06 min, m/z 991.5478), 3 ion (t_R = 6.08 min, m/z 845.4918), 4 ion (t_R = 7.95 min, m/z 845.4921), 5 ion (t_R = 8.37 min, m/z 1,153.6040), 6 ion (t_R = 8.47 min, m/z 1,193.5976), 7 ion (t_R = 8.63 min, m/z 1,123.5930), 8 ion (t_R = 8.86 min, m/z 1,123.5930), 9 ion (t_R = 8.88 min, m/z 1,123.5930), 10 ion (t_R = 9.43 min, m/z 1,165.6030), 11 ion (t_R = 9.48 min, m/z 991.5521), 12 ion (t_R = 9.68 min, m/z 1,165.6040); 13 ion (t_R = 8.60 min, m/z 683.4375), 14 ion (t_R = 10.40 min, m/z 827.4811), 15 ion (t_R = 10.62 min, m/z 827.4809), 16 ion (t_R = 11.02 min, m/z 811.4861), 17 ion (t_R = 11.24 min, m/z 811.4862), 18 ion (t_R = 11.34 min, m/z 665.4270), 19 ion (t_R = 11.59 min, m/z 665.4271), 20 ion (t_R = 12.18 min, m/z 829.4970), 21 ion (t_R = 12.36 min, m/z 829.4972), 22 ion (t_R = 13.31 min, m/z 871.5072), 23 ion (t_R = 13.49 min, m/z 871.5073), 24 ion (t_R = 14.29 min, m/z 811.4860), 25 ion (t_R = 14.49 min, m/z 811.4863), 26 ion (t_R = 15.54 min, m/z 853.4965), 27 ion (t_R = 15.76 min, m/z 853.4968).

Fig. 4

Representative ion-intensity plot for marker ions over 20 samples. (A) Ginsenoside Rb1 at m/z 1,153.6040 (t_R = 8.37 min). (B) Ginsenoside Re at m/z 991.5519 (t_R = 6.06 min). (C) ginsenoside Rg5 at m/z 811.4863 (t_R = 14.49 min). (D) 20S-Ginsenoside Rs3 at m/z 871.5073 (t_R = 13.49 min).

Fig. 5

The HPLC chromatograms of ginseng samples. A: Red ginseng (100°C); B: Red ginseng (120°C); C: Fresh ginseng. (1: Rg₁; 2: Re; 3: Rf; 4: Rg₂; 5: Rb₁; 6: Rc; 7: Rb₂; 8: Rb₃). HPLC, high-performance liquid chromatography.

Fig. 6

The HPLC chromatograms of Red ginseng samples. A: Red ginseng (120°C); B: Red ginseng (100°C). (1: Rg₃). HPLC, high-performance liquid chromatography.

Fig. 7

The changes in HPLC chromatograms of ginsenoside Rb₁ by different steam temperature. A: Red ginseng (100°C); B: Red ginseng (120°C). (1: Rb₁; 2: 20(S)-Rg₃; 3: 20(R)-Rg₃; 4: Rk₁; 5: Rg₅). HPLC, high-performance liquid chromatography.

Fig. 8

Structure of protopanaxatriol ginsenoside.

Fig. 9

Structure of protopanaxadiol ginsenoside.

Fig. 10

Transformation of ginsenosides in Red ginseng. HH: high temperature; HL: low temperature. (ara(f): α-l-arabinofuranosyl; ara(p): α-l-arabinopyranosyl; rha:α-l-ahamnopyranosyl; glc: β-d-glucopyranosyl; xyl: β-d-xylopyranosyl; Mal: malonyl; Bu: trans-but-2-enoyl).