Discrimination of the Geographical Origin of Ginseng (Panax ginseng C. A. Meyer) using Analysis of the Stable Isotope Ratios Combined with Chemometrics
Background : The natural stable isotope ratio of common bio-elements like carbon (C), nitrogen (N), oxygen (O), or sulfur (S) varies with diverse isotope fractionation processes in nature. Therefore, measuring the variation of these stable isotope ratios in ginseng roots can be a feasible tool to discriminate the geographical origins of ginseng in Korea. Methods and Results : The 3-year-old six Korean ginseng cultivars were cultivated at the five regions in Korea, and then used for measuring the stable isotope ratios of C, N, O, and S by isotope ratio mass spectrometry (IRMS). The mean C, N, O, and S stable isotope ratio values in the ginseng roots significantly differed according to the cultivation regions (p < 0.05). However, these isotope ratios in ginseng roots had relatively weak discriminative power against to the ginseng cultivars at each cultivation region. The interaction of the cultivation region and ginseng cultivar type also significantly affected to the C, N, O, and S stable isotope ratio in ginseng roots (p < 0.0001). The two-dimensional plots associated with the N stable isotope ratio can effectively separate the ginseng roots in Jinan compared to those in the other regions. The partial least squares-discriminant analysis showed more significant separation between ginseng geographical origins compared to the principal component analysis. Conclusion : Our findings improve our understanding of how the isotope composition of ginseng roots varies with respect to cultivation regions and cultivars, and suggest that the analysis of the stable isotope ratios combined with chemometrics can be used as a feasible tool to discriminate geographical origin of ginseng in Korea.