The Panax L. (Araliaceae) genus consists of 12 species, including 10 from Asia and two from North America. Three species are commonly used today: Panax ginseng C.A. Mey., known as Ginseng, Renshen, or Korean Ginseng; Panax quinquefolius L., known as American Ginseng or Xiyangshen; and Panax notoginseng (Burk.) F.H. Chen, known as Notoginseng or Sanqi. While these Panax species have different clinical efficacies in Chinese medicine, they share a great deal of similarity in their chemistry and gene sequences, making their authentication difficult.
Currently, quality control of these three ginsengs is based on the relative quantities of saponins . In addition, the ginsengs are graded and priced according to their origins, ages, and morphological characteristics , which are mainly determined after visual or microscopic inspection by experts . However, this morphological method is subjective, and cannot be applied to medicinal products in the form of slices, powders, or decoctions.
Genetically, the three Panax species closely resemble one another. For example, P. ginseng, P. quinquefolius, and P. notoginseng have similar DNA sequences  for nuclear ribosomal DNA, 5S rRNA spacer, and 18S rRNA. Random amplified polymorphic analysis can distinguish the Panax species [4, 5], with restriction to the crude herbs instead of their extracts. Chemically, the important constituents of Panax roots, including ginsenosides Rb1, Rb2, Rd, Rg, and Re, are found in the roots of P. ginseng, P. quinquefolius, and P. notoginseng. The presence of ginsenosides alone cannot offer conclusive evidence for species distinction. In 2006, Yang et al.  demonstrated the use of NMR metabonomics for quality control of commercial ginseng preparations. Similar metabonomic approaches were applied to distinguish the roots of P. ginseng and P. quinquefolius from different countries and ages by Kang et al.  and Lee et al.. However, these previous attempts used methanol extraction, which is not typically used in ginseng preparation for consumption.
Therefore, this study aims to distinguish the Panax species roots from different cultivated regions in China and America in water extracts, that mimics the general way of ginseng consumption, to assess the potential of distinguishing ginseng decoctions by 1H NMR metabonomics.