Bulletins on Adulteration of Cranberry and Ginkgo Published by the
Program
Dietary supplements made with
extracts from cranberry (Vaccinium macrocarpon,
Ericaceae) have seen consistent growth in sales over the past years and are
among the most popular herbal supplements available. The beneficial effects of
cranberry for the prevention of lower urinary tract infections are at least in
part due to the presence of proanthocyanidins (PACs). These compounds are not
easily separated using common chromatographic techniques such as
high-performance liquid chromatography (HPLC) or high-performance thin-layer
chromatography (HPTLC), and are frequently measured using visible
spectrophotometry. However, spectrophotometric methods are often nonspecific
and can be fooled by adding PACs from other sources, such as peanut (Arachis hypogaea, Fabaceae) skin or grape (Vitis vinifera, Vitaceae) seed. Other reports suggest
undeclared addition of anthocyanin-containing extracts, e.g., from black bean (Phaseolus vulgaris, Fabaceae) skin, black rice (Oryza sativa, Poaceae), or hibiscus (Hibiscus sabdariffa,
Malvaceae) calyx to give the ingredient the reddish color suggestive of
cranberry. Available data on occurrence of adulteration have been summarized in
the cranberry Botanical Adulterants
Bulletin by Thomas
Brendler and Stefan Gafner, PhD, published in December 2017.
In early January
2018, the BAPP published the Botanical Adulterants bulletin on
ginkgo leaf extracts. Evidence to support adulteration of extracts made from the leaves of
ginkgo with flavonoids from other botanical sources, in particular buckwheat (Fagopyrum esculentum, Polygonaceae) or Japanese sophora (Sophora japonica, syn. Styphnolobium japonicum,
Fabaceae), is very robust as new publications on the topic emerge on an annual
basis. The addition of these flavonoids brings these “ginkgo”
extracts into compliance with the 24% flavonol glycoside content
standardization.
Recent publications1,2 suggest that over 70% of the analyzed
supplements may be adulterated. Apparently, pressure from dietary supplement
manufacturers to get the lowest price possible for these extracts have led to a
situation where the authenticity of the ginkgo extracts has been compromised by
many suppliers to meet the demand. This bulletin, written by Stefan Gafner, PhD,
has been over two years in the making due to additions of new data on ginkgo
leaf extract adulteration and controversial results about the presence of the isoflavone
genistein in authentic ginkgo leaves.
References
1. Avula
B, Sagi S, Gafner S, Upton R, Wang Y-H., Wang M, Khan IA. Identification of Ginkgo biloba supplements adulteration using high
performance thin layer chromatography and ultra high performance liquid
chromatography-diode array detector-quadrupole time of flight-mass
spectrometry. Anal Bioanal Chem. 2015;407(25):7733-7746.
2. Ma
Y-C, Mani A, Cai Y, Ma J, Thomson J, Peudru F, Chen S, Luo M, Zhang J.Shi Z-T.
An effective identification and quantification method for Ginkgo
biloba flavonol glycosides with targeted evaluation of adulterated
products. Phytomedicine. 2016;23(4):377-387.
