ABC: NYAG misused DNA testing

Media coverage does not mention known limitations of DNA testing protocols.

The New York State Attorney General (AG) Eric T. Schneiderman has issued a press release stating that his office has sent cease-and-desist letters to four major US retail chains informing them that they must stop selling store brands of herbal dietary supplements that were found problematic in DNA barcoding tests conducted for the AG's office.

Schneiderman’s office commissioned testing of store-brand supplements from GNC, Target, Walgreens, and Walmart, including the herbal supplements labeled as echinacea, garlic, ginkgo, ginseng, saw palmetto, St. John’s wort, and valerian. According to the press release, allegedly only 21 percent of the store-brand herbal supplements contained DNA from the plants listed on the products’ labels. The retailer with the least amount (4 percent) of tested products showing DNA from the labeled plants was Walmart. In addition, many products apparently did not contain any DNA from a botanical source.

The AG’s office contracted with Prof. James A. Schulte II, PhD, of Clarkson University in Potsdam, New York, who employed DNA barcode technology to test the supplements. Dr. Schulte has a background in evolutionary biology and reptilian zoology, but is not considered an expert in botany, pharmacognosy, or natural product chemistry—three key scientific areas related to herb and medicinal plant research.

The American Botanical Council (ABC) was contacted by New York Times writer Anahad O’Connor on Monday afternoon requesting a comment on the Attorney General’s (then-embargoed) press release.

Chief Science Officer of ABC and Technical Director of the ABC-AHP-NCNPR Botanical Adulterants Program  Stefan Gafner, PhD, and ABC Founder and Executive Director Mark Blumenthal sent the following statement to Mr. O’Connor, which was not included in the Times’ articles that appeared online and on the front page of the New York Times (above the fold):

The AG’s study is not based on adequate science and its actions are thus premature. The use of DNA barcoding technology for testing of the identity of botanical dietary supplements is a useful but limited technology. DNA testing seldom is able to properly identify chemically complex herbal extracts as little or no DNA is extracted in many commercial extraction processes. Basing its actions on the basis of only one testing technology from only one laboratory, the NY AG results are preliminary and require further substantiation. Additional testing using microscopic analysis and validated chemical methods should be conducted to confirm the initial results upon which the AG is acting.

ABC also added the following statement based on recently published DNA studies on commercial ginkgo extracts conducted at the New York Botanical Garden and the highly respected University of Mississippi’s National Center for Natural Product Research:

“The AG’s test results do not comport with other recently published research on herbal dietary supplements. Two recent tests from reputable laboratories on commercial ginkgo extracts have found ginkgo in all or almost all of the samples tested.”

The Washington Post also posted a story, and other media outlets are expected to follow suit.

According to Blumenthal, “From a scientific perspective, it appears that the NY AG is way out in front of the available scientific evidence to support and substantiate his position. We cannot know this for certain until we know more about the testing protocols, but in general, as we told the New York Times, DNA barcode testing often cannot determine the identity of a botanical material if it’s been extracted, or if the material has been submitted to a prolonged heat treatment,” he continued,  “so, if any of the products tested were extracts—e.g., ginkgo, and possibly the St. John’s wort products—then it’s understandable why they got a negative finding. This also may be true for other products tested, i.e., if they were extracts.”

“Further,” said Dr. Gafner, “it seems as if there wasn’t any verification of the results. As we noted in the statement to the New York Times, microscopy and validated chemical test methods, like those found in official pharmacopeias for these seven herbs, should have been conducted to confirm the DNA findings. The best way to determine the identity of botanical materials and ingredients in finished supplements is to use a range of appropriate methods whenever possible.”

“The action by the New York Attorney General is highly problematic,” added Blumenthal. “We here at ABC are sympathetic with the AG’s obvious concern about the reported problems associated with adulteration of herbal ingredients in dietary supplements. After all, ABC is the international leader in educating the industry, researchers, and health professionals about the problems associated with adulterated botanical ingredients through our leadership of the ABC-AHP-NCNPR Botanical Adulterants Program. However, everything we are doing in our Program is based on scientific research, including evaluation of appropriate testing methods, and full peer review. We respectfully must question whether an appropriate level of scientific rigor has been applied in this case.”

“The New York AG should take every precaution to approach potential ways to deal with this problem by using appropriate protocols, including an extensive review by competent scientists who are familiar with the analysis of botanical dietary supplements,” added Dr. Gafner. “Conducting DNA tests with little or no apparent verification by other test methods, and without employing a second or even a third analytical laboratory to confirm the findings of the first lab results, and then proceeding to engage in regulatory activity is premature based on the evidence they have collected and disclosed thus far. Additional testing in another qualified DNA lab as well as by other appropriate and validated testing methods is required.”

Dr. Gafner emphasized that although some extracts may contain DNA, it is often of low quality or degraded to a point that makes it impossible to perform proper authentication. Other processes, such as extensive heat treatment or submission of plant material to UV light also impact the quality and may lead to erroneous results using DNA methods.

“If, when the dust settles on this issue and all appropriate analytical methods and protocols are used to test these products, and they still confirm the NY AG’s initial tests, only then should the New York AG (and the Food and Drug Administration) pursue appropriate legal and regulatory enforcement options,” said Blumenthal. “However,” he continued, “that can happen only when all appropriate tests are run by people who are expert in the testing of plant materials. Based on what we can determine, that hasn’t occurred here.”


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