Authentication and Chemical Fingerprinting of Economically Important Species

Kew has been using a range of analytical methods based on chemical and DNA fingerprinting to identify the species of plants being traded, their quality as well as identifying new uses.

Different processed forms of Panax ginseng (Asian Ginseng) roots. Methods have been developed at Kew to chemically fingerprint extracts of ‘ginseng’ species for the purposes of authentication and quality control. Photo: Lin Yu-Lin.

Habitat loss, through changes in land use and climate change are placing pressures on plant diversity and the sustainable supply of plants for use by local communities as well as for those entering the trade. These challenges to plant diversity are occurring at a time when there is an increased interest in plant-based products for use in cosmetics, herbal medicines, functional foods, potpourri, dyes and pet products as well as bio-fuels. Kew has been using a range of analytical methods based on chemical and DNA fingerprinting to identify the species of plants being traded, their quality as well as identifying new uses. Authentication of material entering the trade involves not only the identification of the material but investigating whether the plant-derived products contain the appropriate range of compounds associated with their proposed use. Kew is also working with others to evaluate whether the plants are being supplied from sustainable sources. To date, we have studied the uses of over 13,000 species, of which about 3,000 are being traded. In most cases the correct species has been traded, although we are increasingly encountering incidents when the incorrect species has been traded. In other cases the extracts being traded do not contain the appropriate profile of compounds that would support their proposed use. These issues often reveal a lack of knowledge about the plants being used and the methods needed to ensure the appropriate compounds are in the extracts. Over-exploitation of some species, especially those that are wild harvested has identified the need to develop sustainable harvesting practices to avoid adulterants or poor quality material entering the trade.

At a commercial level the outputs of this project have highlighted to companies, health and conservation regulators the need to check the authentication of plants entering the trade. At a community level it has also highlighted the need to select plants for propagation that contain the compounds associated with their proposed use. It has also illustrated the relevance and importance of the living and taxonomic collections at Kew as well as the taxonomic, natural product and biological expertise of the Kew staff in authenticating material.

The main authentication project can be broken down into a series of sub-projects that deal with different commodity and user groups and are funded through varied sources. For example, the use of plant-derived extracts in over-the-counter health products and cosmetics has been funded through a grant from the EPSRC and Proctor and Gamble. Important issues associated with the identification of plants entering the trade for use in traditional Chinese medicine (TCM) continue to be addressed by the Chinese Medicinal Plants Authentication Centre at RBG Kew. This centre is taking a key role in the EU seventh Network Programme on “Good practice in traditional Chinese medicine research in the post-genomic era” (www.gp-tcm.org).

The outputs of the project are being published in peer-reviewed journals, trade journals and books, and contribute to the monographs for the European and British Pharmacopoeias. Within RBG Kew this project has close links with the Wellcome Trust supported Medicinal Plant Name Index project as well projects being coordinated through other science teams such as the “Systematic phytochemistry of legumes” and Chemosystematics and biological activity of Lamiaceae”.

Key publications 2006-2011

• Chen, S., Lin, Y., Qian, Z. & Leon, C.J. (2010). A colored identification atlas of Chinese materia medica and plants as specified in the pharmacopoeia of the People’s Republic of China. Chinese Pharmacopoeia Commission and Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, People’s Medical Publishing, 2 vols, pp. 1200.
• Heinrich, M., Chan, J., Wanke, S., Neinhuis, C. & Simmonds, M.S.J. (2009). Local uses of Aristolochia species and content of nephrotoxic aristolochic acid 1 and 2–A global assessment based on bibliographic sources. Journal of Ethnopharmacology 125: 108–144.
• Howes, M.-J.R., Kite, G.C. & Simmonds M.S.J. (2009). Distinguishing Chinese star anise from Japanese star anise using thermal desorption-gas chromatography-mass spectrometry. Journal of Agricultural and Food Chemistry 57: 5783–5789.
• Kite, G.C., Veitch, N.C., Boalch, M.E., Lewis, G.P., Leon, C.J. & Simmonds, M.S.J. (2009). Flavonol tetraglycosides from fruits of Styphnolobium japonicum (Leguminosae) and the authentication of Fructus Sophorae and Flos Sophorae. Phytochemistry 70: 785–794.
• Kite, G.C., Green, P.W.C., Veitch, N.C., Groves, M.C., Gasson, P.E. & Simmonds, M.S.J. (2010). Dalnigrin, a neoflavonoid marker for the identification of Brazilian rosewood (Dalbergia nigra) in CITES enforcement. Phytochemistry 71: 1122–1131.