New Test Identifies Ginkgo in Supplements

Often called a living fossil, the ginkgo tree is unique in that no living variants exist, and its fan-shaped leaf impression has been identified in fossils dating back 270 million years.

Ginkgo supplements derived from the tree’s leaves are marketed for a number of indications. Such claims include improved cognitive capacity via improved blood perfusion and mitochondrial function.

In a study published online in December 2014 in Genome, Damon P. Little, a researcher from The New York Botanical Garden, examined commercial products claiming to contain ginkgo. He looked at gingko’s unique DNA mini-barcode, which has a C at nucleotide position 107, unlike other gymnosperms that have a T.

Little examined 40 ginkgo-containing products to estimate the frequency of mislabeled ginkgo herbal dietary supplements on the market in the United States, and he was able to extract DNA from 37 of the products.

Of those products, 31 contained identifiable Ginkgo biloba DNA, but 6 contained fillers without any detectable G. biloba DNA. The researcher noted that those 6 products may have contained gingko at the time they were manufactured, but it is possible that the product degraded, making the DNA unusable.

The researcher proposed this assay as a useful tool for supplement manufacturers to ensure that their supplements contain G. biloba.

Evidence supports claims that ginkgo decreases blood viscosity and increases blood perfusion; is effective adjunctive therapy for chronic schizophrenia; and improves elements of cognitive function in dementia patients. However, there is no evidence supporting claims of improved concentration, memory, or executive function in healthy individuals. In general, patients report few and minor adverse events related to ginkgo products. In 2012, Americans spent more than $25 million on gingko supplements.

Products containing ginkgo contain 2 major pharmacologically active fractions: flavonoids and terpene trilactones. Both appear to enhance mitochondrial function by scavenging reactive oxygen species.