Analytical discrimination between sources of ginseng using Raman spectroscopy

Abstract

Ginseng is a widely used medicinal product that grows mainly in Korea, China and America. American ginseng is classified as an endangered species, and so the import and export of this type of ginseng is illegal in certain countries. Due to this restriction it is becoming increasingly important to be able to distinguish between different types of ginseng. FT-Raman spectroscopy has the ability to discriminate between ginseng specimens according to the country of origin and the effects of processing on the ginseng material. The ginsenoside content of ginseng differs in both conformation and concentration depending on the source of the ginseng, which means that ginseng grown in different countries should express unique spectral features. The presence or absence of these features, therefore, could indicate the geographical origin of the sample. Several spectral features were identified for a range of ginsengs, such as a peak at 980 cm⁻¹ that was only found in Chinese ginseng, and the different wavenumber positions of characteristic ginseng bands near 1600 cm⁻¹. This indicates that Raman spectroscopy can be used to pinpoint the origin of an unknown ginseng sample and that it would provide a rapid nondestructive analytical technique for formally discriminating between restricted and permitted imports.