The ABC-AHP-NCNPR Botanical Adulterants Prevention Program (BAPP) has published a new Laboratory Guidance Document (LGD) on cranberry (Vaccinium macrocarpon).

Cranberry-derived dietary supplements and beverages are widely used for the prevention and adjuvant treatment of recurrent urinary tract infections. In the U.S., cranberry was the third top-selling botanical dietary supplement ingredient in U.S. mainstream retail outlets (drug stores, grocery stores, etc.) in 2017, with sales of $68.12 million.

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 considered the main cranberry compounds responsible for preventing bacterial adhesion in the urinary tract. PAC concentrations vary from 0.8% to 24% in commercial cranberry extracts, with the majority of products containing between 0.8% and 1.5% PACs. Depending on the PAC concentration, bulk cranberry products were sold for $50 to $600 per kg in 2017.

The availability of lower-cost PACs from other plant sources, such as peanut (Arachis hypogaea) skin or grape (Vitis vinifera) seed, has led some unscrupulous suppliers to dilute or replace cranberry PACs—without labeling such dilution or replacement—for financial gain. Other known adulterants of cranberry include anthocyanin-rich extracts from other lower-cost materials. Anthocyanins range in color from red to blue, and anthocyanin-rich extracts are used to mimic the red color found in authentic cranberry extracts. A summary of these methods of cranberry adulteration was published in BAPP’s Cranberry Botanical Adulterants Prevention Bulletin in December 2017. 

The new LGD was written by John H. Cardellina II, PhD, a noted expert in natural products chemistry and analysis, and American Botanical Council (ABC) Chief Science Officer and BAPP Technical Director Stefan Gafner, PhD. The LGD evaluates the usefulness of published analytical methods to detect cranberry fruit product adulteration and summarizes the main advantages and disadvantages of each method regarding its suitability for use in a quality control laboratory. The document also details the chemical composition of cranberry fruit, potential confounding species, and known adulterants. The LGD was peer reviewed by 20 international experts from academia, the government, third-party contract analytical laboratories, and the herbal industry.

Dr. Gafner explained: “The variability in manufacturing processes and, accordingly, the composition of commercial cranberry ingredients makes it challenging to find an analytical method that is able to detect all the different types of adulteration. Depending on the product specifications, a suite of test methods may be needed for unambiguous identification of a cranberry fruit extract.”

Mark Blumenthal, ABC founder and executive director, and BAPP founder and director, said: “As with the case of other adulterated botanical materials on which we have reported, this new Laboratory Guidance Document provides a much-needed resource for industry and third-party analytical labs to ensure that they are using an analytical method that is robust and fit for purpose to detect the adulteration and fraud that is occurring in the global cranberry extract market.”

Mr. Blumenthal added: “Older analytical methods may not be able to accurately detect the type of chemical manipulations that are used to adulterate cranberry materials in the marketplace, and any company that relies on some of the older, inadequate methods would be doing so at their own risk — that is, they may be ‘approving’ adulterated material.”

Dr. Cardellina noted: “There has been a veritable explosion of interest and effort in developing suitable methods to ensure the authenticity and purity of cranberry products, whether they are juice or extract based. It is likely that further methodological studies will be reported in the near future, and BAPP will keep its stakeholders and the public apprised of such developments.”