CAMAG has produced an application note describing an HPTLC methodology for the identification of SJW and a simple test for adulteration.
Hypericum perforatum L., known as St. John's Wort (SJW), is the most commonly used Herbal Medicinal Product for treating mild-to-moderate depression . Products made with SJW were among the 40 top-selling Herbal Supplements in the USA in 2016 . Due to the popularity of this botanical dietary supplement, there is a potential for economically driven adulteration of SJW products particularly with other Hypericum species .
Triggered by the fact that some SJW ingredients on the market have given unusual results (such as odd colours of solutions obtained during sample preparation), several commercial samples labelled to contain extracts of H. perforatum were analysed by HPTLC using methodology from the Unites States Pharmacopoeia (USP)  with additional detection under white light. Uncommon fingerprints were obtained for several products, suggesting presence of other species, degradation products, and/or polar additives (food dyes) . A new HPTLC method allows identification of such additives .
This application note shows the HPTLC methodology for identification of SJW and a simple test for adulteration: by scanning densitometry and HPTLC-MS the presence or absence of food dyes can be confirmed.
 Klaus L., Michael B., Matthias E., Cynthia M.: St John's wort for depression. Meta-analysis of randomised controlled trials. The British Journal of Psychiatry, 2005, 186(2): 99-10. DOI: 10.1192/bjp.186.2.99.
 Smith T., Kawa K., Eckl V., Morton C., Stredneyd R.: Herb Supplement Sales Increase 7.7% in 2016. HerbalGram, 2017, 115: 56-65.