BAPP review determines adulteration rates for 5 top botanicals

A review published in a peer-reviewed chemical journal assessing the adulteration prevalence of five top-selling herbal ingredients found rates ranging from 57% of products analyzed to a low of 17%.

The new study was published in the journal Natural Products Reports, a Royal Academy of Chemistry journal. It was the work of well-known herbal experts Stefan Gafner, Ph.D. and Mark Blumenthal — both with the American Botanical Council (ABC) —and Nilüfer Orhan, Ph.D., a Turkish pharmacognosist. All three professionals are affiliated with the Botanical Adulterants Prevention Program (BAPP).

BAPP is a cooperative effort between ABC, the American Herbal Pharmacopoeia and the National Center for Natural Products Research (NCNPR) at the University of Mississippi.

The herbs discussed in the report are black cohosh (Actaea racemosa) rhizome, echinacea (Echinacea angustifolia, E. pallida, and E. purpurea) herb and/or root, elder (Sambucus nigra) berry, ginkgo (Ginkgo biloba) leaf and turmeric (Curcuma longa) rhizome. 

The report, “Estimating the extent of adulteration of the popular herbs black cohosh, echinacea, elder berry, ginkgo, and turmeric – its challenges and limitations,” assembled data from 78 studies looking at adulteration in the target species.

Challenges and limitations abound

Ascertaining overall numbers of adulterated products is surprisingly difficult. What consumers might want to know is how likely it is they would unknowingly buy a fraudulent product. Regulators might want to know what the true extent of the problem is, as a basis for making future policy decisions.

The authors presented a detailed discussion of the challenges of arriving at an overall figure for the adulteration rates in the target botanicals. For starters, a crucial consideration that can get glossed over in these discussions is the market share of each product.

For example, if a study examined 10 products in a specific herbal category and found half of them to be adulterated, that is seemingly an easy calculation— yielding an adulteration rate of 50%. But if the unadulterated products comprised more than 90% of the overall market, the actual rate of adulteration is much smaller.

Another complicating factor is the analytical methods used to detect adulteration. These methods range from microscopy to various kinds of chemical analysis and DNA testing. Not all these methods are fit for purpose in every case. And despite the publication of many BAPP lab guidance documents over the years detailing the best methods to use for various applications, there remains a wide variance in the methods employed by academia and industry.

Another question is the identity of the entities testing for adulteration. For example, the authors cited one study showing a far lower percentage of adulteration (7%) in elderberry products tested by third-party labs compared to the rate found by elderberry product manufacturers themselves (40%). A possible reason for this is that companies having robust supply chain practices that include rigorous supplier verification and use of third-party labs might be much more certain of what they’re buying. Consequently, testing failures for those companies would be rarer than for firms taking their chances in buying ingredients on the open market.

“Adulteration and fraud are unfortunate facts of commerce,” said ABC’s founder and executive director Blumenthal. “The question is to what extent does it affect the current market for herbal dietary supplements and related natural plant- and fungal-based ingredients?

“Our paper demonstrates that estimating the extent of adulteration using published data is a very challenging and imperfect process, and the results cannot be deemed to be definitive,” he added. “They must be viewed within the context of creating a process with inadequate data.”

Extent of the problem

The review included a total of 77 publications and 2,995 samples across the five botanicals. The Ginkgo leaf extract samples (n = 533) had the highest estimated adulteration rate with 56.7%, followed by powdered plant materials or extracts of black cohosh root/rhizome (n = 322) with 42.2%, echinacea root/herb (n = 200) with 28.5%, elderberry (n = 695) with 17.1%, and turmeric rhizome (n = 1247) with 16.5%.

“The numbers obtained for the extent of adulteration of the five botanicals investigated for this systematic review may not be representative for the overall adulteration rate in the global herbal dietary and food supplement industry, but it is clear that adulteration of botanical ingredients is a problem and impacts a substantial portion of products sold as dietary or food supplements,” noted ABC’s Gafner.