Researchers Propose New Method to Detect St. John’s Wort Adulteration

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A new study authored by several industry experts proposes new “enhanced authentication procedures” for detecting adulteration of St. John’s wort (Hypericum perforatum L.). Writing in the Journal of AOAC International, researchers detail a new reversed-phase high-performance thin-layer chromatography (HPTLC) method that may be more effective than previous methods at detecting the latest adulterants used in place of St. John’s wort today, such as synthetic dyes.

The study-a collaborative effort by leading researchers from Arizona Nutritional Supplements (Chandler, AZ), CAMAG (Muttenz, Switzerland), Alkemist Laboratories (Costa Mesa, CA), the U.S. Pharmacopeial Convention (Rockville, MD), and the American Herbal Products Association (Silver Spring, MD)-investigated 37 St. John’s wort dry extracts, finished products, and bulk raw-herb samples.

Researchers found that approximately 38% of the samples were inauthentic, with the new reversed-phase HPTLC method able to identify the adulterants as synthetic dyes or other ingredients with uncharacteristic flavonoid patterns.

Sidney Sudberg, founder of CSO of Alkemist Labs, told Nutritional Outlook that new testing techniques for St. John’s wort are necessary because “previous techniques do not detect or address the potential adulteration of [St. John’s wort] with dyes and/or related species.”

“The new methods proposed in the publication specifically target the types of adulteration that are found in many SJW samples lately,” Sudberg said. “These methods have been enhanced so that we can better detect ‘newly found’ adulteration.  The new analytical methods differ from previous techniques by using different mobile phases that are designed to specifically look for the adulterants we are currently seeing in the market.”

Read more:

Dietary Supplements: New Testing Tools to Catch Botanical Adulteration

U.S. Herbal Supplement Sales Climb 7.5% in 2015

DNA Testing: Weeding Out Botanical Adulterants

Michael Crane
Associate Editor
Nutritional Outlook Magazine
michael.crane@ubm.com

References:

Frommenwiler DA et al., “St. John’s wort versus counterfeit St. John’s wort: an HPTLC study,” Journal of AOAC International, vol. 99, no. 5 (September 2016): 1204–1212