Botanical Adulterants Prevention Program (BAPP) Publishes Grape Seed Extract Laboratory Guidance Document

AUSTIN, Texas (February 27, 2019) — The ABC-AHP-NCNPR Botanical Adulterants Prevention Program (BAPP) announces the publication of a new Laboratory Guidance Document (LGD) on Grape Seed Extract (GSE). The new guidance document is the 50th peer-reviewed publication from the program.

Extracts from the seeds of grapes (Vitis vinifera) have been shown to improve parameters related to cardiovascular health in human clinical trials. Despite promising results in clinical studies, GSE dietary supplements are not among the 40 top-selling botanical dietary supplement ingredient in the US (natural food stores, drug stores, grocery stores, etc.) according to the latest ABC/HerbalGram herb market report for 2017.

Grape seeds are a rich source of proanthocyanidins (PACs), to which many of the commercially available bulk ingredients are standardized. Despite the relative low cost of grape seeds as a byproduct of the juice and wine industries, PACs from other plant species are available as economic adulterants. These include, for example, PACs derived from peanut (Arachis hypogaea) skin, or from Masson pine (Pinus massoniana) bark.

The availability of these lower-cost PACs combined with the difficulties in unambiguously identifying the source material of PAC-rich extracts, has made it easier for GSE adulteration to occur for financial gain of dishonest suppliers.

The intricate chemical challenges in the determination of grape seed as the origin of GSE are manifold. Routine analytical methods using chromatography (e.g., high-performance liquid chromatography, HPLC) are generally not suitable to separate the larger PAC molecules. High-resolution mass spectrometry (MS) is useful to determine the molecular weight distribution of PACs, but such instrumentation is not available in many industry quality control laboratories. Further, genetic methods (DNA testing) may not be successful because of the extensive processing leading to DNA fragmentation, and the interference of PAC-rich extracts with enzymatic processes such as the polymerase chain reaction.

The new LGD was written by Steve A. Kupina and Mark A. Kelm, PhD, directors of quality and technology and research and development, respectively, at botanical ingredient manufacturer Polyphenolics; Maria J. Monagas, PhD, scientific liaison for dietary supplements and herbal medicines at the United States Pharmacopeial (USP) Convention; and Stefan Gafner, PhD, chief science officer of the American Botanical Council (ABC), and the technical director of BAPP.

The LGD provides an evaluation of the usefulness of published analytical methods to detect GSE adulteration, and summarizes the main advantages and disadvantages of each method regarding its suitability for use in a quality control laboratory. In addition to the assessment of the analytical methods, the document details the chemical composition of grape seed, potential confounding species, and known adulterants. The GSE LGD has been peer-reviewed by 25 international experts from third-party contract analytical laboratories and the herbal industry.

Gafner explained: “There is a reason why BAPP’s most recent laboratory guidance documents on cranberry and grape seed extracts have dealt with PAC-rich ingredients. PAC-derived materials are most often difficult to authenticate, and many suppliers have been using inappropriate tests based on spectrophotometric methods as a means to document the authenticity. Many of the lessons learned from GSE adulteration may be applied to the verification of the identity of other ingredients that contain condensed tannins. As such, this laboratory guidance document may not only benefit those working on GSE, but also those whose duty it is to verify the identity of condensed tannin-containing plant materials, e.g., cinnamon bark, apple fruit, or pine bark extracts.”

Mark Blumenthal, ABC founder and executive director, and BAPP founder and director, said, “On behalf of all of us at the ABC-AHP-NCNPR Botanical Adulterants Prevention Program, we announce this particular publication, the Grape Seed Extract Laboratory Guidance Document – our 50th peer-reviewed publication. This new milestone for BAPP speaks to the high output of the program, and shows our continued commitment to the high quality and reliability of our extensively-peer-reviewed publications. That is, the GSE LGD reflects both the quality and quantity of our research and educational efforts to provide responsible members of the herb and dietary supplement industry worldwide with authoritative resources that can help them properly authenticate botanical raw materials, extracts, and essential oils -- and detect those that may be adulterated.”

The GSE LGD is the 8th publication in the series of LGDs and the 50th peer-reviewed publication published by BAPP. As with all publications in the program, LGDs 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).

About the ABC-AHP-NCNPR Botanical Adulterants Prevention Program

The ABC-AHP (American Herbal Pharmacopoeia-NCNPR (National Center for Natural Products Research) Botanical Adulterants Prevention Program is an international consortium of nonprofit professional organizations, analytical laboratories, research centers, industry trade associations, industry members, and other parties with interest in herbs and medicinal plants. The program advises industry, researchers, health professionals, government agencies, the media, and the public about the various challenges related to adulterated botanical ingredients sold in commerce. To date, more than 200 United States and international parties have financially supported or otherwise endorsed the program.

To date, the program has published 50 extensively peer-reviewed articles, Botanical Adulterants Bulletins, Laboratory Guidance Documents, and Botanical Adulterants Monitor e-newsletters. All of the program’s publications are freely available on the program’s website.