New analytical method identifies adulterated St John’s wort products

By Stephen Daniells contact

- Last updated on GMT

© iStock
© iStock
Almost 40% of a sample of 37 St John’s wort products may be adulterated with synthetic dyes and/or uncharacteristic flavonoids, says a new study.

A paper published in the Journal of AOAC International​ outlines the development of a new reversed-phase HPTLC method to identify what was causing unconventional fingerprints using preliminary HPTLC analysis following the United States Pharmacopeia (USP) monograph methodology.

The paper was authored by experts from CAMAG, Alkemist Labs, USP, Arizona Nutritional Supplements and AHPA.

“I think this work is an excellent example illustrating the great potential of HPTLC, unlocked by standardized methodology, suitable equipment and validated methods provided by CAMAG, when it comes to analysis of highly complex and naturally variable samples such as botanicals” ​said Débora Frommenwiler from CAMAG and lead author on the paper.

$8.5 million in sales

St. John’s wort (Hypericum perforatum​ L.) is most commonly used for depression. There is strong scientific evidence that it is effective for mild to moderate depression​.

According to the recent report from the American Botanical Council, sales of St John’s wort were $6 million in US mainstream multi-outlet channel in 2015, and a further $2.5 million in the natural retail channel (HerbalGram 111​).

The new research found that, of the 37 samples of St John’s wort tested – including herb, dry extracts, and commercial products – approximately 38% were inauthentic because they contained a mixture of synthetic dyes and uncharacteristic flavonoids (22%) or they only showed the uncharacteristic flavonoid pattern only (16%).

“The herbal products industry has a long history of proactively collaborating to innovate resources that help ensure high-quality products. This research provides one more tool to help the industry accomplish this shared goal and comply with federal regulations,”​ said Dr. Maged Sharaf, chief science officer at the American Herbal Products Association and co-author on the paper.

“The research provides the industry with simple HPTLC tests to reliably assess the purity of St. John’s Wort as required by the Food and Drug Administration’s current good manufacturing practices for dietary supplements.”

Further analysis of the dyes revealed that the majority of the samples contained very little tartrazine, similar levels of amaranth and Brilliant Blue, and a large amount of Sunset Yellow. “This fact led us to believe that a fixed mixture of at least four dyes has been added to these extracts with the intent of adulteration,”​ wrote the researchers.

The data revealed that only 5 of the 12 retail products tested (purchased in 2015 in the US and on the Internet) showed fingerprints compliant with the USP 38 St John’s wort monographs.

“We are not surprised to hear of this level of adulteration, as we see these problems routinely with many popular herbs of commerce,” ​Sidney Sudberg, Alkemist Labs Founder and CSO, and co-author on the paper, told NutraIngredients-USA. "Since their popularity precedes many of these botanicals, it is the perfect opportunity for certain unethical manufacturers to take advantage of an industry that is still maturing when it comes to quality control

“The solution for all companies that care about the quality they produce is to be sure that whoever is doing the testing for them is up to date with the most current level of adulteration in the industry and how to detect it.  It seems the cheaters are always one step ahead of us and it takes us seeing the issues more than once to detect a pattern or trend in the data, to help stop the unscrupulous manufacturers from taking advantage of unaware dietary supplement companies.”

The authors proposed enhanced authentication procedures and a decision flowchart to systematically rule out St John’s wort adulteration.

Staying ahead of the adulterers

Sudberg confirmed that Alkemist Labs already uses these and other methods to detect any adulteration of St John’s wort and many other popular botanicals.

“But once some manufacturers find out we have ‘cracked their code’, they move on and develop something new to again offset their costs and offer poorer quality material than is expected from a legitimate and ethical supplier.”

Source: Journal of AOAC International
Volume 99, Number 5, Pages 1204-1212
“St. John's Wort versus Counterfeit St. John's Wort: An HPTLC Study”
Authors: D. Fromenwiler, et al.

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