Botanical Adulterants Prevention Program Publishes Ginkgo Leaf Extract Laboratory Guidance Document

AUSTIN, Texas, May 10, 2022 (GLOBE NEWSWIRE) — The ABC-AHP-NCNPR Botanical Adulterants Prevention Program (BAPP) announces the publication of a new Laboratory Guidance Document (LGD) on ginkgo (Ginkgo biloba) leaf extracts.

Ginkgo leaf extracts are widely used around the globe to improve mental performance, for circulatory issues such as peripheral arterial occlusive disease, and for vertigo and tinnitus. In the United States, ginkgo leaf extract dietary supplements have been consistently among the 25 top-selling herbal supplements with over $33 million in sales in 2020 in the natural and mass-market channels combined.¹

Over the past 20 years, at least 27 publications in the peer-reviewed scientific literature have documented cases of adulteration of ginkgo leaf extract ingredients and finished consumer products. Such adulteration generally involves the addition of undeclared flavonol-rich ingredients or highly purified flavonoids (e.g., quercetin or rutin) from lower-cost sources, most commonly extracts or purified fractions of the flowers and leaves of Japanese sophora (Styphnolobium japonicum, syn. Sophora japonica). Of the 501 samples analyzed in these 27 papers, 242 (48%) were considered to be adulterated according to criteria established by the authors of each of these publications, suggesting that ginkgo leaf extract adulteration is widespread.

Undeclared added materials typically are rich in rutin and/or quercetin in order to increase the extract content of flavonol glycosides to 24%, the minimum amount specified on the labels of most commercial dietary supplements to meet the same standardization requirement as the extract EGb761® (Dr. Willmar Schwabe GmbH & Co. KG, Karlsruhe, Germany) — the pioneering and most clinically tested ginkgo leaf extract in the world. Since both rutin and quercetin are also found in ginkgo leaves, the detection of adulteration of commercial ginkgo materials can be challenging.

The new LGD assesses the usefulness of 78 laboratory analytical methods to authenticate ginkgo leaf extract and/or detect ginkgo leaf extract adulteration. The document was compiled and written by Stefan Gafner, PhD, chief science officer of the American Botanical Council (ABC) and technical director of BAPP. It was peer reviewed by 30 experts from academia, government, and the herbal dietary supplement industry in the United States and internationally.

Gafner explained: “Finding a suitable analytical method to authenticate ginkgo leaf extracts is time-consuming at least in part because of the large number of methods available in the peer-reviewed literature, national pharmacopeias, and other official compendia. Not many botanical ingredients have been subject to such a vast body of analytical work dedicated to its quality control. We hope that this is where the ginkgo laboratory guidance document can be of value to the international medicinal plant community since it provides an overview of relevant, reliable, and fit-for-purpose methods in a single document.”

“Standardized ginkgo leaf extract is one of the most clinically researched phytomedicinal products in the world,” said Mark Blumenthal, founder and executive director of ABC and founder and director of BAPP. “Many consumers purchase ginkgo products and are sometimes recommended to use them by their health care practitioner in the hope that these products will deliver a clinically documented health benefit. However, if the product contains an intentionally adulterated extract, it is not likely that it will produce the health benefits observed in published clinical trials. Adulteration of ginkgo, or of any herb product, is a great disservice to the millions of people who wish to improve or maintain their health naturally.”

The ginkgo leaf extract LGD is the 13th publication in the series of LGDs and the 73rd peer-reviewed publication published by BAPP. As with all BAPP publications, LGDs are freely accessible on the Program’s website (registration required).

About the ABC-AHP-NCNPR Botanical Adulterants Prevention Program