Protecting endangered and CITES listed species : a review of wild American ginseng (P. quinquefolius) identification methods

Abstract

Ginseng, a popular herb in traditional medicine, is commonly believed to possess therapeutic benefits including anti-inflammatory, anticancer, neuroprotective, and antioxidant effects. The popularity of the herb encourages overharvesting of the species’ wild populations, consequentially reducing genetic diversity and threatening their long-term viability. The species has been listed under the Convention on International Trade in Endangered Species (CITES) Appendix II, indicating that it is vulnerable to extinction if its current level of trade and consumption continues uncontrolled. This review summarizes the status of current ginseng harvesting regulations, taxonomy, and species identification methods. Although classical techniques for ginseng species identification such as morphological, genetic, and protein analysis are available, these methods are limited in application by sample quality as commercial ginseng products are typically processed as teas, powders or extracts which reduces the sensitivity of each method. To address these limitations, researchers have shifted their attention to investigate differences in chemical profiles between ginseng species, giving rise to the field of chemotyping. Ginsenosides, a group of bioactive compounds in ginseng, play a large role in chemotyping ginseng species as the unique health benefits of different ginseng species implies variable ginsenoside content between species. These unique chemical profiles are observed through either spectroscopic or mass spectrometry based analytical methods, with the latter showing the greatest potential for ginseng species identification. Analytical separation techniques for mass spectrometry based chemotyping currently emphasize gas chromatography and liquid chromatography, including ultra- high performance liquid chromatography (UHPLC) that is widely used in metabolomics. Coupling these separation techniques with detection methods including mass spectrometry (e.g. GC/MS, LC/MS), tandem mass spectrometry (LC/MS2), and high-resolution mass spectrometry (e.g., quadrupole time-of-flight (QTOF), orbitrap) showcases potential for species’ identification and determination of provenance by chemical profiling. A more recent addition to the analytical toolbox is direct analysis in real time (DART) with QTOF-MS. This technique holds the key to a fast and convenient method without the need for chromatographic separation of analytes for ginseng species and provenance identification to enforce harvesting regulations and protect wild populations.