Bulletin highlights adulteration of 'folkloric' star goldenseal

Goldenseal, whose Latin name is Hydrastis canadensis​, is a member of the Ranunculaceae botanical family of plants that are distributed worldwide.  It is one of the best-known plants that came out of North American herbal traditions, said ABC executive director Mark Blumenthal.

“It is one of the top selling Native American plants along with black cohosh, American ginseng and echinacea. Those are probably the four biggest,”​ Blumenthal told NutraIngredients-USA.

The adulteration series is part of the ABC-AHP-NCNPR Botanical Adulterants Program, which is a joint project with the American Herbal Pharmacopoeia and the National Center for Natural Products Research at the University of Mississippi.

The Goldenseal Bulletin was written by Michael Tims, PhD, academic director of herbal medicine at the Maryland University of Integrative Health. It begins with general information on the plant species, followed by data on its cultivation, harvest, and market size. The main section covers known adulterants, frequency of adulteration, potential therapeutic and/or safety issues with the adulterating species, and analytical approaches to detect the adulterant. 

Goldenseal is native to North America and grows in much of the eastern half of the United States and Canada. Historically, Native Americans used preparations of goldenseal root and rhizome for a variety of conditions, including respiratory ailments, skin disorders, and infectious diseases. Goldenseal preparations still are used externally for their wound-healing and antimicrobial properties, but, more commonly, the herb is offered in combination herbal supplements for internal use — often with echinacea (Echinacea​ spp.) — that are marketed for immune support and other functions. In 2013 and 2014, goldenseal-echinacea combination products were the 15th top-selling herbal supplement in US natural retail outlets according to SPINS data quoted in the report.

Popularity based on folklore​

Blumenthal said that goldenseal is unique in that it has achieved its popularity based almost entirely on traditional history of use. It is a plant that has been little studied in its whole form, he said.

“This is one of the few popular herbs that is popular based on folkloric use, not based on a plethora of published trials. What research there is is based on berberine itself, the primary, though not the only, isoquinoline alkaloid found in goldenseal,” ​he said.

The goldenseal document is the fourth in ABC’s adulteration series, following documents on bilberry, grape seed extract and skullcap.  The bulletins are laborious to produce, Blumenthal said, because in an effort to make them authoritative, they are extensively peer reviewed. The goldenseal edition went through 14 peer reviewers.

“We want these publications to be deemed authoritative, and I think they are,” ​Blumenthal said.

The primary purpose of the goldenseal bulletin, as with the other bulletins published by the program, is to alert the marketplace to what kind of adulteration is occurring and with what adulterants so that responsible companies will know what to look for.  Blumenthal and his collaborators are always careful to only mention those cases of adulteration for which there is documented proof, so he was unwilling to put a number on the amount of adulteration that is occurring, but he said it is a feature of the marketplace.

“We do know it is occurring based on reports we get from laboratories. In order to be more precise, you’d have to do large scale, wide testing of multiple brands found in the marketplace and nobody has really done that test,” ​Blumenthal said.

“We are confirming what in many cases were suspicions, allegations and hearsay in the industry. We take that responsibility very seriously, so we have to find specific examples of that adulteration,”​ he said.

Accidental and intentional adulteration​

As with other botanicals, as demand goes up, prices do, too, and the supply has a hard time keeping up with that curve. A significant portion of goldenseal in the marketplace is wildcrafted, mostly in Appalachia, and habitat loss has affected the supply. Some cases of adulteration with related species may be accidental, and some cases lower cost botanicals may be intentionally substituted in to ‘cut’ the final product.  (Blumenthal hastened to add that multi species products that are properly labeled would not be considered as part of this adulteration picture.)

Among the common recent adulterants listed in the bulletin are Japanese goldthread (Coptis japonica​), yellow root (Xanthorrhiza simplicissima​), Oregon grape (Mahonia aquifolium​, Berberidaceae), celandine (Chelidonium majus​, Papaveraceae), barberry (Berberis ​spp., Berberidaceae), and yellow dock (Rumex ​spp., Polygonaceae) root. In addition, while most top quality goldenseal products make use of material from the rhizome, some formulators use additional material from the leaf, which also contains berberine and other alkaloids, though in different ratios and at much lower concentrations. Unlike the adulteration picture in some other botanicals, such as with skullcap, these related species that may appear as adulterants do not seem to pose much of a safety issue, so the matter revolves mostly around transparency and quality.

Burnishing the quality image​

Blumenthal said that while the bulletins are not pushed out directly to some of the industry’s prominent critics, he believes the overall program is gaining traction, and is helping to counteract the view in some quarters that herbal product formulation has low quality standards.

“We haven’t intentionally tried to market them to specific known critics of the industry per se, but we are aware that a number of people who are counted as critics of the industry are aware of our program,”​ he said.

The goldenseal bulletin will be followed in fairly short order by others on black cohosh, arnica, ashwagandha, cranberry, St. John’s wort, ginkgo and American and Asian ginseng. The production process is not linear, Blumenthal said, and depends on the schedules of peer reviewers and how many changes they might call for.

“We’ve been working on these for  along time and now a bunch of them are coming together at the same time;  a perfect storm, if you will,”​ Blumenthal said.