Statement on use of DNA testing for botanical identity

[NOTE: This statement was developed in response to the March 30, 2015 agreement between the New York Attorney General and GNC that will require GNC to use DNA source material traceability standards utilizing DNA barcoding for any “active” herbal/botanical ingredients prior to extraction, if any, used in the GNC Herbal Plus brand products as soon as a DNA barcode becomes available. The statement provides the view of the American Herbal Products Association of the current state of the science of the use of DNA barcoding as a technique for authenticating the identity of herbal materials for this purpose and is intended to explain any misunderstandings that may arise out of the March 30 agreement as to the currently limited applicability of this analytical technique.]

1. The NY AG/GNC agreement defines “DNA Barcode” to mean “a reference sequence of DNA associated with a unique species of plant,” and “DNA Barcoding” to refer to “a technique for authenticating organic materials using DNA Barcodes.”
2. The NY AG/GNC agreement defines the term “’active’ herbal/botanical raw material ingredient” as “the plant part or extract identified as coming from the plant listed in the active ingredients on the product label.”

Herbal dietary ingredients, whether they are whole herbs, ground herbs, herb extracts, or herbal products used in the manufacture of dietary supplements are required by FDA cGMP regulations to have their identity verified by one appropriate test or examination (1). This must be done by the manufacturer prior to manufacture of the product, and numerous established methods currently exist for this purpose.

Verification of the identity of herbal ingredients by DNA analysis is still in the early stages of scientific development (2). Therefore, at the present time, identifying herbal ingredients by DNA analysis is often not scientifically valid and has limitations inherent in its use for this purpose (2-4). DNA analysis can generate false negative results due to the normal and expected lack of DNA in some processed herbal ingredients or due to inhibitory effect of other constituents in the ingredients (5-6). False positive results may likewise be obtained from the presence of incidental DNA (5-6). At a minimum, DNA test results for a particular herb cannot be relied upon in the absence of standards whose identity has been conclusively established through taxonomic botanical analysis (2). Finally, this technology is incapable of identifying plant parts as required by federal law.

FDA noted in response to DNA barcode testing questions posed by Senators Hatch and Heinrich that it is not currently using this technology “agency-wide for plant identification” (7). Importantly, FDA advised the Senators that:

“FDA is researching the development of validated DNA-sequencing-based identification methods for botanical materials and is working on the development of a plant species DNA library. Currently, if FDA were to use DNA methods on botanical extracts, we would use them in combination with established chemical or other acceptable methods historically used to verify the identity of these products.”

Identification of herbal supplement ingredients must be accomplished by well-established, scientifically valid methods. Additional confirmation of the identity of an herbal ingredient using DNA testing or any other analysis is unnecessary if the ingredient has been properly identified by at least one scientifically valid method. Furthermore, reliance on DNA testing for herbal identity by a manufacturer would not be compliant with FDA cGMPs unless the firm using such methodology has established it to be appropriate and scientifically valid for this purpose.

Citations

1. 21 CFR 111.75(a).
2. Hollingsworth PM, Graham SW, Little DP. (2011) Choosing and Using a Plant DNA Barcode. PLoS ONE 6(5): e19254. doi:10.1371/journal.pone.0019254.
3. Maia VH, Mata CS, Franco LO, Cardoso MA, Cardoso SRS, et al. (2012) DNA Barcoding Bromeliaceae: Achievements and Pitfalls. PLoS ONE 7(1): e29877. doi:10.1371/journal.pone.002987.
4. Roy S, Tyagi A, Shukla V, Kumar A, Singh UM, et al. (2010) Universal Plant DNA Barcode Loci May Not Work in Complex Groups: A Case Study with Indian Berberis Species. PLoS ONE 5(10): e13674. doi:10.1371/journal.pone.0013674.
5. Heubl G. (2013) DNA-Based Authentication of TCM-Plants: Current Progress and Future Perspectives. In Wagner and G. Ulrich-Merzenich (eds.), Evidence and Rational Based Research on Chinese Drugs. Springer-Verlag Wien.
6. Reynaud DTH, Mishler BD, Neal-Kababick J, and Brown PN. (2015). The Capabilities and Limitations of DNA Barcoding of Botanical Dietary Supplements. Retrieved from http://www.ahpa.org/Portals/0/pdfs/The-Capabilities-and-Limitations-of-DNA-Testing-FINAL_AHPA.pdf (accessed April 14, 2015).
7. FDA response to Senators' inquiry on DNA testing of herbal supplements. (2015). Retrieved from http://www.ahpa.org/Portals/0/pdfs/15_0318_FDA_to_Hatch-Heinrich_DNA_testing.pdf (accessed April 14, 2015).