Botanical Adulterants Prevention Program updates Ginkgo extract lab analysis guidance
12 May 2022 --- The American Botanical Council’s (ABC) Botanical Adulterants Prevention Program (BAPP) unveiled a new advisory for detecting the adulteration of Ginkgo biloba leaf extracts.
The Laboratory Guidance Document (LGD) assesses the efficacy of 78 laboratory analysis methods used to verify the authenticity of Ginkgo leaf extract or detect alteration. The LGD was peer-reviewed by 30 US and international experts from governmental, academic and herbal dietary supplement industry backgrounds.
Author of the study, Dr. Stefan Gafner, informs: “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.”
The latest LGD is the 13th put out by ABC, and the 73rd peer-reviewed publication by BAPP.He continues that not many botanical ingredients have been subject to such a vast body of analytical work dedicated to 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.”
In the US, ginkgo leaf extract is classified as a dietary supplement and has consistently placed among the top 25 best-selling herbal supplements. The ABC says the supplement won over US$33 million in sales in 2020 alone across the combined natural and mass-market channels.
Adulteration abounds
The ABC says that almost 30 scientific publications have documented instances of the adulteration of ginkgo leaf extract ingredients and D2C products across the past two decades.
Of the 501 samples involved in these studies, 242 (48%) were adulterated, according to criteria set out by the relevant authors.
The findings indicate that adulteration may be rampant throughout industry. The adulteration process reportedly usually involves adding in undeclared flavonol-rich substances or highly-purified flavonoids like quercetin or rutin to increase the extract content of flavonol glycosides to 24%.
This is the minimum amount specified on the labels of most commercial dietary supplements to meet the standardization requirements of the extract EGb761 manufactured by Dr. Willmar Schwabe GmbH & Co. KG. The ABC refers to this extract as the “most clinically tested ginkgo leaf extract in the world.”
As rutin and quercetin are also present in ginkgo leaves, detecting adulteration in commercial ginkgo materials is often challenging. 
The news could impact how supplements manufacturers demonstrate product purity.
“Quality control tests relying on measuring solely quercetin, kaempferol, and isorhamnetin after hydrolysis are not sufficient to guarantee absence of adulteration,” says the LGD.
These adulterating substances usually come from lower-cost sources, often from extracts or purified fractions of Japanese sophora (Styphnolobium japonicum, or Sophora japonica) leaves and flowers.
Analyzing efficacy
According to Mark Blumenthal, founder and executive director of ABC and founder and director of BAPP, standardized ginkgo leaf extract is one of the most clinically researched phytomedicinal substances across the globe.
“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,” he explains.
“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.”
According to the ABC, Ginkgo leaf extracts are widely employed as a brain-boosting ingredient to aid mental performance, as well as help with circulatory issues like peripheral arterial occlusive disease, as well as tinnitus and vertigo.
Recently, NutritionInsight spoke with industry players on the ever-growing nootropics space. The new LGD will no doubt impact how this space continues to unfold.
Edited by Olivia Nelson
