Thus, metabolomic approaches combined with multivariate analysis can be an effective strategy for comprehensively evaluating the qualities of medicinal plants [16]. A few studies have applied these spectroscopic techniques for metabolic discrimination of ginseng plants. For example, these techniques have been used to determine the cultivation age of ginseng root [28] and [29], classify ginseng according to cultivation area or origin [30], [31], [32] and [33], identify biomarkers capable of distinguishing different ginseng varieties [27], [34] and [35], and quantify chemical compounds in ginseng roots.

The aerial part of ginseng dies at the end of the growing season and is newly produced the following spring. In addition, as the ginseng plant is competent to flower from the 3rd yr of cultivation [36], a flower-inducing substance could be present in the PLX3397 in vitro metabolites of the aerial part generated from 2-yr-old roots. Therefore, it is an interesting dilemma whether or not metabolic profiling of a leaf sample would represent the age of the root. If so, metabolites related to aging of the root would be transported from the root to the aerial part.

Therefore, the aim of this study was to examine the possibility that leaf samples instead of the root can be used for the discrimination of cultivars or cultivation ages using Fourier transform (FT)-IR spectral analysis combined with multivariate analysis. Leaves of four cultivars, P. ginseng Meyer cv. Yunpung, Kumpung, Chunpung, and an open-pollinated Dasatinib in vivo variety, were provided by Jeollabuk-do Agricultural Research and Extension Services ( Fig. 1). Whole leaf samples from each individual were excised and rapidly frozen by pouring liquid N2 over leaves after sample collection. Leaf samples were freeze-dried, ground into powders, and stored at −70°C before analysis. A total of 480 leaf samples belonging to 12 categories corresponding to the four different cultivars and three different cultivation ages (1 yr, 2 yr, and 3 yr) were analyzed in this study. Crude whole-cell extracts were prepared

Aldehyde dehydrogenase for FT-IR analysis. Five milligrams of each ginseng leaf powder was combined with 100 μL of extraction buffer [20% (v/v) methanol] in a 1.5 mL microfuge tube, mixed vigorously, and incubated in a 50°C water bath for 10 min with occasional vortexing. Mixtures were centrifuged at 13,000× g for 5 min, and supernatants were transferred to fresh tubes. Centrifugation was repeated if cell debris was not fully removed. These crude whole-cell extracts from ginseng leaves were stored at −20°C prior to FT-IR spectroscopy analysis. For FT-IR spectroscopy analysis, 5 μL aliquots of prepared crude whole-cell extracts were loaded onto a 384 well silicon plate on a hotplate prewarmed to 37°C. After the samples were dried, the 384 well silicon plate was placed in a microplate reader unit (HTS-XT; Bruker Optics GbH, Ettlingen, Germany).