DNA barcode testing has been erroneously used—again—to target supplements. Will supplement companies change their testing methodology now?

Todd Runestad, Content Director, NaturalProductsInsider.com, Sr. Supplements Editor

September 10, 2015

7 Min Read
New NY AG campaign against botanicals targets devil's claw

The New York Attorney General’s campaign against the herbal supplements industry continued this week when its office sent cease-and-desist letters to 13 companies that sell devil’s claw, because the products contain two different species of the botanical and one reference book says only one species is the proper one—despite longstanding industry practice and botanical experts saying otherwise.

And it turns out the parade of supplement industry trade group leaders to the NY AG’s office in the wake of its original campaign against adulterated botanicals in February, counseling that the use of DNA barcode testing on herbal extracts is inappropriate, has fallen on deaf ears.

Also, it turns out that being popular is more important than being right, especially to a politician with his sights set on the governor’s mansion.

"This may be a hair-splitting botanical distinction," said Mark Blumenthal, founder and executive director of the American Botanical Council, "but it certainly is not a legal or regulatory one, especially since authoritative sources recognize both species as being 'devil's claw.'"

In botanical classification and nomenclature, devil's claw is usually known scientifically by its Latin name, Harpagophytum procumbens, where Harpagophytum is the genus of the plant and procumbens refers to the species of the plant. The DNA-barcoding tests commissioned by the NY AG showed that some herbal supplements actually contain Harpagophytum zeyheri, a slightly different form of devil's claw, i.e., a different, but very closely related species. In effect, they are like two siblings, said the ABC.

"Both species of devil's claw have a similar chemical profile," said Thomas Brendler, a medicinal plant expert and editor of the African Herbal Pharmacopeia, a compilation of technical information of various African medicinal plants, including their botany, growing conditions, range of habitat, chemistry, and traditional and modern medicinal activities and uses.

"While both species differ marginally in shape and chemical composition, both are considered equally effective," he added.

According to various government-recognized medicine evaluation bodies and pharmacopeias, the two species of devil's claw are considered interchangeable for the purpose of their use for their medicinal actions. These organizations include the European Medicines Agency, the European Pharmacopoeia and the unofficial ESCOP (European Scientific Cooperative for Phytotherapy), a pan-European consortium of medicinal plant experts. Also listing both species as interchangeable is the proposed monograph "Harpagophytum species root" in the United States Pharmacopeia's Herbal Medicines Compendium.

However, a 2014 published report discovered that H. procumbens contains higher levels of pharmacologically active constituents and, while it’s been noted that the two species are used interchangeably, H. procumbens is superior--and the blending of H. zeyheri in devil’s claw formulations could account for studies that show less-than-stellar effects.

Yet even this study was criticized because it used only one sample of each plant, whereas a minimum of 10 samples would be considered more accurate due to natural variation of plant chemicals.

Grown principally in the African nation of Namibia, the plant is used as an anti-inflammatory, especially for joint health, via cox-2 inhibition. Some 20 human clinical trials conducted over the last 30 years have demonstrated its safety and efficacy in alleviating pain in joints and the back.

Brendler added that many, possibly most, devil's claw extracts in the world market are based on mixtures of the two species, as are devil's claw herbal teas and dried powdered root materials used in supplements and other products. Both species of devil's claw have been in the market in the United States since the 1980s, he noted.

According to data ABC used for its annual herb market report, devil's claw is a relatively low-selling herb in the United States. In 2014, devil's claw ranked 162nd in sales in the U.S. mainstream retail market and 150th in the natural and health foods channel. Total estimated sales of devil's claw dietary supplements in the United States range from approximately $250,000 to up to $500,000.

You say DNA. I say WTF?

The NY AG’s testing methodology in this case, like its other high-profile tests, use DNA barcoding technology, which is new and not used often—or at all, in the case of botanical extracts. So regardless of the issue of which species is most effective against pain and inflammation, the issue remains over whether the wrong weapon was used even in the right war.

"DNA barcoding (DNAB) is a new science,” said Loren Israelsen, president of the United Natural Products Alliance trade group. “Like all new technologies, its role and utility in the dietary supplement industry is only now evolving. Scientific organizations that set quality standards and establish analytical methods are investigating the potential of DNAB as an additional tool to improve quality and plant identification. And, while the New York attorney general thinks DNAB is a useful enforcement tool, we hope the proper role of DNAB doesn’t become a weapon before it becomes a generally accepted analytical tool for botanical products.”

Hope springs eternal, but the NY AG shows no sign of letting up from using this novel testing protocol, which herbal experts around the world deride as “not fit for purpose” for botanical extract finished products (as opposed to raw materials) because the extraction process routinely denatures or destroys plant DNA.

“When a scientific study tests numerous herbal supplements manufactured by more than a dozen companies and finds the wrong plant in just about every one, it raises more troubling questions about whether people who buy dietary supplements are getting what they pay for,” said New York Attorney General Eric Schneiderman in a statement.

Clearly, it has not occurred to the NY AG that, perhaps, instead of just about every supplement being adulterated, perhaps the study test is not the right one.

It again bears repeating that herbal experts the nation over have sent letters or met with the AG’s office to testify that DNAB testing is not the correct test, and that secondary testing protocols should also be employed to validate the DNAB tests. Perhaps the most detailed correspondence came from Roy Upton, executive director of the American Herbal Pharmacopoeia, which publishes monographs that detail, among other things, all appropriate testing protocols for particular botanical species.

"With rare exception, DNA barcoding is not an appropriate technology for testing the identity of ingredients in extracts,” wrote Upton to the NY AG. “By definition, extracts are made by extracting the desired constituents from the plant material itself into a liquid medium, a process that either does not maintain the DNA or significantly denatures it. The extract is then processed and dried onto an appropriate carrier. In that process, an extract is sometimes subjected to heating or further mechanical filtering, which similarly either removes or further denatures DNA if present. With most extracts there is no actual plant tissue left or, if any material remains, it can be greatly degraded. Because of this, there is either no DNA in finished products, such as those tested, or there is too little intact DNA to get an accurate finding. There is a possibility that some of these products may have been adulterated, but the percentages will likely change if the appropriate testing technology is applied.”

Lalalalalalala, the NY AG said. To bring home his point, he was able to extract an accord with Nature’s Way to use DNAB testing across its “Green” and “Purple” herbal product lines that contain one or two ingredients. In addition, Nature’s Way, in a letter to the NY AG’s office, said that when scientifically valid DNAB tests are ready for prime time, the company will use DNAB as an additional testing method to ensure its devil’s claw products do not contain Harpagophytum zeyheri, and it will ensure that its product labels identify only H. procumbens as the sole devil’s claw species.

And this is the way politicians play politics with science. By getting a company to start using DNAB--even in a limited way on incoming raw materials but not on the finished products because everyone knows that’s not appropriate for extracts—the NY AG appears to demonstrate that its testing protocols are accurate and appropriate.

And a large supplements company, in this case Nature’s Way (back in February it was GNC but none of the other large national retailers), comes quickly out of the gate saying it will abide the demands because it’s all about quality--even though Nature’s Way was not one of the 13 companies issued cease-and-desist letters.

“As it has always done,” wrote Chad Wiegand, senior vice president and general counsel for Nature’s Way, to the NY AG, “Nature’s Way will continue to invest in its quality systems and will leverage the advancements in science to instill trust in the consuming public. Nature’s Way’s products are of the highest quality and will be accurately represented to consumers accordingly.”

About the Author(s)

Todd Runestad

Content Director, NaturalProductsInsider.com, Sr. Supplements Editor, Natural Products Insider

I've been writing on nutrition science news since 1997. I'm The content director for NaturalProductsInsidercom and digital magazines. Other incarnations: supplements editor for newhope.com, Delicious Living and Natural Foods Merchandiser. Former editor-in-chief of Functional Ingredients magazine and still cover raw material innovations and ingredient science.

Connect with me here https://www.linkedin.com/in/toddrunestad/

My daily vitamin regime includes a morning smoothie with a range of powders including protein, collagen and spirulina; a quality multi, B complex, C with bioflavonoids, >2,000IU vitamin D, E, magnesium, high-selenium yeast, PQQ, choline, alpha-lipoic acid with carnitine, coQ10, fish oil concentrate, probiotics and some adaptogenic herbs. 

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