## 3 Discussion  
Ginsenosides are the main components in the chemical profiles of ginseng, and some prevalent analytical methods, such as UPLC-MS and \({}^{1}\)H NMR are developed to distinguish different types of ginseng based on the diversity of ginseng. As is well known, ginseng has its own odor, and its aroma characteristics has attracted wide attention for ginseng identification. Thus, GC-MS also enables ginseng discrimination based on the volatile components. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Groups for** & \multirow{2}{*}{**Q-Marker’ Name**} & **VIP** & \multirow{2}{*}{**\(p\)**} & **GCC\({}_{\text{5-years}}\)** & **GCC\({}_{\text{10-years}}\)** & **GCC\({}_{\text{15-years}}\)** \\ \cline{5-7}
**Comparison** & & & & & & \\ \hline \multirow{5}{*}{GC\({}_{\text{5-years}}\) vs.} & Hexanal & 5.45061 & \textgreater{}0.000 & 6282.94 \(\pm\) 1163.54 & 2298.02 \(\pm\) 168.66 & 3768.41 \(\pm\) 803.90 \\  & 2-Oxo-pentanoic acid & 1.60289 & \textgreater{}0.000 & 397.04 \(\pm\) 131.61 & 53.36 \(\pm\) 16.51 & 226.85 \(\pm\) 237.52 \\  & Hepanal & 1.40708 & \textgreater{}0.000 & 411.09 \(\pm\) 77.96 & 143.42 \(\pm\) 19.44 & 170.35 \(\pm\) 24.52 \\ \cline{5-7}  & Benzaldehyde & 1.03157 & \textgreater{}0.000 & 210.09 \(\pm\) 48.35 & 60.35 \(\pm\) 9.45 & 80.37 \(\pm\) 13.16 \\  & Octanal & 1.20191 & \textgreater{}0.000 & 293.63 \(\pm\) 41.48 & 96.77 \(\pm\) 10.99 & 120.21 \(\pm\) 21.23 \\  & 2-Isopropyl-3-methoxypyrazine & 1.46396 & 0.001 & 509.32 \(\pm\) 125.61 & 212.52 \(\pm\) 111.73 & 313.61 \(\pm\) 120.50 \\ \hline \multirow{5}{*}{GC\({}_{\text{5-years}}\) vs.} & Hexanal & 5.41556 & 0.001 & 6282.94 \(\pm\) 1163.54 & 2298.02 \(\pm\) 168.66 & 3768.41 \(\pm\) 803.90 \\  & 2-Oxo-pentanoic acid & 1.44353 & 0.023 & 397.04 \(\pm\) 131.61 & 53.36 \(\pm\) 16.51 & 226.85 \(\pm\) 237.52 \\ \cline{1-1}  & Hepanal & 1.61564 & \textgreater{}0.000 & 411.09 \(\pm\) 77.96 & 143.42 \(\pm\) 19.44 & 170.35 \(\pm\) 24.52 \\ \cline{1-1}  & Benzaldehyde & 1.31916 & 0.001 & 210.09 \(\pm\) 48.35 & 60.35 \(\pm\) 9.45 & 80.37 \(\pm\) 13.16 \\ \cline{1-1}  & 2-Isopropyl-3-methoxypyrazine & 1.52673 & 0.020 & 509.32 \(\pm\) 125.61 & 212.52 \(\pm\) 111.73 & 313.61 \(\pm\) 120.50 \\ \hline \multirow{2}{*}{GC\({}_{\text{10-years}}\) vs.} & Hexanal & 5.33736 & 0.006 & 6282.94 \(\pm\) 1163.54 & 2298.02 \(\pm\) 168.66 & 3768.41 \(\pm\) 803.90 \\ \cline{1-1}  & 2-Oxo-pentanoic acid & 1.82677 & 0.003 & 397.04 \(\pm\) 131.61 & 53.36 \(\pm\) 16.51 & 226.85 \(\pm\) 237.52 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The detailed information of the six potential chemo-markers among GCG with 5-,10-,15-growth years. Figure 4: Multivariate statistical analysis base on the volatile components from GCG with 5-, 10-, 15-growth years. (**A**) PCA score plots; (**B–D**) OPLS-DA score plots; (**E–G**) S-plots; (**H**) The contents of the five growth-year-dependent markers to distinguish GCG with 5-, 10-, 15-growth years. (\(p\)-value * \(<\) 0.1; ** \(<\) 0.01; *** \(<\) 0.001). According to their different growth environments and cultivation modes, \(\text{MCG}_{5,10,15-\text{years}}\) and \(\text{GCG}_{5,10,15-\text{years}}\) have different volatile chemical profiles. To further systematically compare the similarities and differences of the volatile components contained in \(\text{MCG}_{5,10,15-\text{years}}\) and \(\text{GCG}_{5,10,15-\text{years}}\), and particularly to compare the composition variations with growth years, HS-SPME-GC-MS coupled with chemometrics was developed to discriminate the volatile component profiles and subsequently to discover differentiating chemical markers. First, a total of 46 volatile components were preliminarily characterized in the samples by using the NIST database and the Wiley library. According to reports in the literature, the main volatile components of ginseng are sesquiterpenoids and sesquiterpenols, which have anticancer, anti-inflammatory, and immunomodulatory pharmacological activities [18,19].