Systematic development of a group quantification method using evaporative light scattering detector for relative quantification of ginsenosides in ginseng products

Classification of three types of ginseng samples based on ginsenoside profiles: appropriate data normalization improves the efficiency of multivariate analysis

Background

It is well known that ginsenosides are the main active ingredients in ginseng, and they have also been important indexes for assessing the quality of ginseng. However, the absolute contents of ginsenosides in ginseng were shown to be varied with the origin, cultivated type, cultivated year and climate. It is a great challenge to distinguish the commercial types of ginsengs according to the content of one or several ginsenosides.

Methods

The common commercial types of ginsengs are white ginseng (WG), red ginseng (RG), American ginseng (AG). To clearly illustrate the differences among WG, RG and AG at the ginsenosides level, we established a strategy for the detection and identification of ginsenosides based on an optimized LC-Q-Orbitrap MS/MS method coupled with an in-house database of ginsenosides. Before and after the normalization, the ginsenosides datasheet was analyzed and compared using several state-of-the-art multivariate statistical analysis methods.

Results

Here, 81 ginsenosides were identified in different ginseng samples. The majority of the ginsenosides (59 in 81) were all shared by WG, RG and AG. When the shared ginsenosides datasheet was normalized by the level of ginsenoside Ro, our analysis strategy clearly divided the ginseng samples into three groups (i.e., WG, RG and AG groups). We found that the ginsenoside profiles in RG and WG were significantly different from those in AG. The potential markers and multivariate diagnostic models differentiating the three types of ginsengs were also indicated.

Conclusion

Our novel methodology based on ginsenoside profiles is more robust than existing methods, and data normalization is required to improve the efficiency of multivariate statistical analysis.

Analysis of Ginsenoside Content (Panax ginseng) from Different Regions

Recently Panax ginseng has been grown as a secondary crop under a pine tree canopy in New Zealand (NZ). The aim of the study is to compare the average content of ginsenosides from NZ-grown ginseng and its original native locations (China and Korea) grown ginseng. Ten batches of NZ-grown ginseng were extracted using 70% methanol and analyzed using LC-MS/MS. The average content of ginsenosides from China and Korea grown ginseng were obtained by collecting data from 30 and 17 publications featuring China and Korea grown ginseng, respectively. The average content of total ginsenosides in NZ-grown ginseng was 40.06 ± 3.21 mg/g (n = 14), which showed significantly (p < 0.05) higher concentration than that of China grown ginseng (16.48 ± 1.24 mg/g, n = 113) and Korea grown ginseng (21.05 ± 1.57 mg/g, n = 106). For the individual ginsenosides, except for the ginsenosides Rb2, Rc, and Rd, ginsenosides Rb1, Re, Rf, and Rg1 from NZ-grown ginseng were 2.22, 2.91, 1.65, and 1.27 times higher than that of ginseng grown in China, respectively. Ginsenosides Re and Rg1 in NZ-grown ginseng were also 2.14 and 1.63 times higher than ginseng grown in Korea. From the accumulation of ginsenosides, New Zealand volcanic pumice soil may be more suitable for ginseng growth than its place of origin.

Method development for the certification of a ginsenoside calibration solution via liquid chromatography with absorbance and mass spectrometric detection

The research presented here describes the development of two analytical methods for use in the certification of a ginsenoside calibration solution Standard Reference Material (SRM) 3389 consisting of seven ginsenosides: Rg1, Re, Rf, Rb1, Rc, Rb2, and Rd. The new methods utilized the liquid chromatographic (LC) separation of ginsenoside mixtures with absorbance detection (UV) and mass spectrometry (MS). Ginsenosides Rb3, Rg2, Rg3, Rh1, and Rh2 were evaluated for use as internal standards for LC/MS measurements. The 12 ginsenosides were baseline resolved by gradient elution LC/UV, with an initial mobile phase composition of 22% acetonitrile and 78% water, flow rate of 0.7 mL/min, and column temperature of 25 °C. The work presented here includes a detailed investigation into the optimization of the chromatographic conditions to minimize measurement biases that result from unresolved constituents. Temperature and mobile phase composition are known to play a significant role in column selectivity; however, flow rate is expected to influence primarily the separation efficiency and detection sensitivity. In the current study, column selectivity changed with changes in flow rate and the relative retention of ginsenoside Rg2 and Rh1 changed as the flow rate increased from 0.6 mL/min to 1.0 mL/min.

A novel and effective mode-switching triple quadrupole mass spectrometric approach for simultaneous quantification of fifteen ginsenosides in Panax ginseng

BACKGROUND

Panax ginseng (PG) is one of the most valuable and frequently used phytomedicine in Asia. In the current Chinese Pharmacopeia, only three ginsenosides, Rg1, Re and Rb1, were set as standard compounds for the quality evaluation of PG. However, only these three compounds could hardly reflect the quality and therapeutic efficacy of this traditional Chinese medicine (TCM).

PURPOSE

Quantification analysis of quality markers (Q-markers) in PG is meaningful for determining the quality of this herbal medicine.

METHOD

By combining the modes of multiple reaction monitoring (MRM) and single ion monitoring (SIM) of tripe quadrupole mass spectrometry (QqQ-MS) through a mode-switching function, a novel, sensitive and effective LC-MS/MS method has been established to simultaneous quantify fifteen Q-markers in PG in one run time cycle. In order to comprehensively evaluate the quality of ten batches of PG, hierarchical clustering analysis (HCA) and the complete linkage method were conducted on the data of the contents of fifteen ginsenosides.

RESULTS

Thirteen Q-markers, including four pairs of isomers with the same product ions and approximately the same retention times, have been well-separated by MRM. Meanwhile, the other two Q-markers with no fragments have also been quantified by SIM. Chromatographic separation was carried out on a reversed-phase C₁₈ column by stepwise gradient elution with a mobile phase of water (containing 0.1% formic acid, v/v) and acetonitrile. Good linearity was observed with the correlation coefficients (r²) greater than 0.99. The intra- and inter-day precisions as well as repeatability of all of the investigated Q-markers were all no more than 5.91%. The average recoveries varied from 83.06% to 116.42%, with relative standard deviation values (RSDs) less than 6.73%. The total contents of the fifteen ginsenosides in ten batches of PG were in the range of 15.54-24.03 mg/g. The results indicated that the growing region has a significant impact on the contents of ginsenosides in PG.

CONCLUSION

The proposed approach could be readily utilized as a comprehensive approach for determining the consistency of the quality and therapeutic efficacy of PG, and it might be an example for the selection of Q-marker standards for the Chinese Pharmacopoeia.

Integrated Transcriptomic and Metabolomic Analysis of Five Panax ginseng Cultivars Reveals the Dynamics of Ginsenoside Biosynthesis

Panax ginseng C.A. Meyer is a traditional medicinal herb that produces bioactive compounds such as ginsenosides. Here, we investigated the diversity of ginsenosides and related genes among five genetically fixed inbred ginseng cultivars (Chunpoong [CP], Cheongsun [CS], Gopoong [GO], Sunhyang [SH], and Sunun [SU]). To focus on the genetic diversity related to ginsenoside biosynthesis, we utilized in vitro cultured adventitious roots from the five cultivars grown under controlled environmental conditions. PCA loading plots based on secondary metabolite composition classified the five cultivars into three groups. We selected three cultivars (CS, SH, and SU) to represent the three groups and conducted further transcriptome and gas chromatography-mass spectrometry analyses to identify genes and intermediates corresponding to the variation in ginsenosides among cultivars. We quantified ginsenoside contents from the three cultivars. SH had more than 12 times the total ginsenoside content of CS, with especially large differences in the levels of panaxadiol-type ginsenosides. The expression levels of genes encoding squalene epoxidase (SQE) and dammarenediol synthase (DDS) were also significantly lower in CS than SH and SU, which is consistent with the low levels of ginsenoside produced in this cultivar. Methyl jasmonate (MeJA) treatment increased the levels of panaxadiol-type ginsenosides up to 4-, 13-, and 31-fold in SH, SU, and CS, respectively. MeJA treatment also greatly increased the quantity of major intermediates and the expression of the underlying genes in the ginsenoside biosynthesis pathway; these intermediates included squalene, 2,3-oxidosqualene, and dammarenediol II, especially in CS, which had the lowest ginsenoside content under normal culture conditions. We conclude that SQE and DDS are the most important genetic factors for ginsenoside biosynthesis with diversity among ginseng cultivars.