Ginkgo biloba has been one of the most widely used, scientifically standardized extracts for more than 20 years. Over 120 studies attest to its value in addressing: cerebral insufficiency, dementia, and circulatory (peripheral vascular) problems. Unfortunately, due to its high production cost and value, Ginkgo extract is also prone to adulteration or spiking in a number of ways.
ENI has over 15 years of proven quality testing on Ginkgo extracts. We released our first report on Ginkgo adulteration in 2006, (in association with American Herbal Pharmacopoeia (AHP), and Eurofins Labs). An update to this report, ‘Ginkgo Adulteration & Identification with Fructus sophorae (Sophora japonica)’, detailed a new method developed by ENI to detect adulteration of Ginkgo by F.saphorae. This report and method was cited in the American Botanical Council’s ‘Adulteration of Ginkgo biloba Leaf Extract’, Botanical Adulterants Prevention Program Bulletin (2018). 
PureLeaf™ Ginkgo biloba extract undergoes a series of very specific analyses to assure that it is free from adulterants, and conforms to the highest grade of extracts available.
PureLeaf™ Ginkgo sets a significantly higher standard and additional control points when compared with the regular Ginkgo 24/6 commonly used in the industry. These include:
- Flavone glycoside ratio [i.e., Kaempferol (K) vs. Quercetin (Q) and vs. Isorhamnetin (I)] is set to more closely resemble their natural ratios in a fresh Ginkgo leaf. It also helps detecting the adding of adulterants, (e.g., rutin) to elevate the total flavonol glycosides level.
- The levels of Ginkgolides (A+B+C) in the extract are quantified and controlled. The Bilobalide level is also set to ensure it falls within the naturally occurring range.
- Ginkgolic acid, which has been associated with contact allergies at high levels, is controlled ≤ 5.0 ppm.
- A limit of 4% Rutin and 0.5% Free Quercetin in unhydrolyzed extracts is specified and controlled.
PureLeaf® Ginkgo Extract is also tested to be in full compliance with the current USP monograph, including the ratios of different flavonoids, terpene lactones, as well as the limits of Rutin and free Quercetin. All this detailed analysis works together to prevent known or potential adulteration of the extract.
The work put into the development and testing of PureLeaf® Ginkgo extract represents most clearly the founding and ongoing principles of Ethical Naturals, Inc.
 Gafner, F. 2018. Adulteration of Ginkgo biloba Leaf Extract. Botanical Adulterants Prevention Program, Botanical Adulterants Bulletin. ABC, AHP, NCNPR (http://herbalgram.org). ENInature verified