The ABC-AHP-NCNPR Botanical Adulterants Program has published a new Botanical Adulterants Bulletin (BAB) on cranberry (Vaccinium macrocarpon, Ericaceae).

Cranberry dietary supplements are widely used for the prevention and adjuvant treatment of recurrent urinary tract infections. Cranberry was the second top-selling botanical dietary supplement ingredient in U.S. mainstream retail outlets in 2016, with an 11.9% increase in sales compared to the previous year.
 
There are important differences in the composition of the various cranberry supplements on the market. This is particularly true with regard to the content of proanthocyanidins (PACs), which are the cranberry compounds responsible for preventing bacterial adhesion in the urinary tract. The dried press cake, which is the solid material obtained after the fruit juice has been squeezed out, contains ca. 0.8% to 1.5% PACs. The dried press cake makes up over 50% of the cranberry dietary ingredient supply (i.e., the material sold in bulk for processing into finished cranberry supplements). Other important cranberry ingredients are whole cranberry fruit extracts and blends of cranberry juice extracts with cranberry fruit extracts with 3% to 5% PACs, as well as pure cranberry juice extracts containing 12% to 24% PACs. Ingredients with higher concentrations of PACs are much more expensive.
 
The availability of lower-cost PACs from other plant sources, such as peanut (Arachis hypogaea, Fabaceae) skin or grape (Vitis vinifera, Vitaceae) seed, has led some unscrupulous suppliers to dilute or replace cranberry PACs—without labeling such dilution or replacement—for financial gain. Other adulterants include anthocyanin-rich extracts from other lower-cost ingredients, such as mulberry (Morus spp., Moraceae) fruit, hibiscus (Hibiscus sabdariffa, Malvaceae) calyx, black bean (Phaseolus vulgaris, Fabaceae) skin, or black rice (Oryza sativa, Poaceae). Anthocyanins have a color ranging from red to blue, and anthocyanin-rich extracts are used to mimic the red color found in authentic cranberry extracts.
 
The new bulletin, written by ethnobotanist and herb industry consultant Thomas Brendler, and American Botanical Council (ABC) Chief Science Officer and Botanical Adulterants Program Technical Director Stefan Gafner, PhD, provides information on the growing range, production, and market importance of cranberry and its extracts. It also lists the known adulterants, potential therapeutic and/or safety concerns associated with the adulterated ingredients, and laboratory analytical approaches to detect adulterants. Twenty-one expert peer reviewers from academia and industry provided input on the cranberry Bulletin.
 
Dr. Gafner explained: “The fact that cranberry extracts are relatively expensive, and that lower-cost PACs from other sources are available, make them an obvious target for economically motivated adulteration.” He also noted that “some of the commonly used laboratory analytical methods like HPTLC or HPLC-UV may be fooled by the addition of extraneous PACs. Therefore, adulteration may go undetected unless more sophisticated instrumentation is used, such as MS fingerprinting or HPLC-MS.”

Mark Blumenthal, ABC founder and executive director, and Botanical Adulterants Program founder and director, said: “Cranberry is one of the most popular herbal dietary supplements in the U.S. market, used by millions of consumers to help maintain the health of their urinary tracts. By publishing this bulletin on the adulteration of cranberry, it is our hope that more supplement manufacturers will be alerted to the unfortunate practices of some unscrupulous ingredient suppliers, thereby not only helping to protect the supplement manufacturers to ensure that they purchase properly authenticated cranberry ingredients, but also to help ensure that consumers are able to purchase authentic, reliable cranberry supplements.”
 
The goal of the Botanical Adulterant Bulletins is to provide accounts of ongoing issues related to botanical identity and adulteration. This allows quality control personnel and lab technicians in the herbal medicine, botanical ingredient, dietary supplement, cosmetic, conventional food, and other industries, where botanical ingredients are used, to be informed on adulteration problems that are apparently widespread and/or that may imply safety concerns. 

The cranberry bulletin is the 12th publication in the series of BABs and the 37th peer-reviewed publication published by the program. As with all publications in the program, the bulletins are freely accessible to all ABC members, registered users of the ABC website, and all members of the public on the Program’s website (registration required).