BBC TV Host Investigates Herbal Products
Containing Milk Thistle, Ginkgo, or Evening Primrose
As part of the BBC TV series “Trust me – I’m a doctor,” host
Christoffer van Tulleken, MD, clinical research fellow at the University
College London (UCL) in London, United Kingdom, linked up with researchers at
the UCL School of Pharmacy in order to assess the identity of ingredients
claimed on labels of herbal products sold either as traditional herbal
medicines (THMs), where products are registered as drugs based on
a ‘tradition of use,’
or as food supplements.1,2 Over 70 products, purchased from various
retail stores and Internet retailers in the UK, were analyzed by
high-performance thin-layer chromatography (HPTLC) in the laboratory of Michael
Heinrich, PhD, professor of pharmacognosy at the UCL School of Pharmacy. The
results of the analysis (images of the ginkgo and milk thistle analyses are
shown on the BBC website1) evidenced that every product sold in the
THM category contained the ingredient claimed on the label. However, eight of
the 30 (27%) ginkgo (Ginkgo biloba, Ginkgoaceae) food supplements had
little or no ginkgo extract in them. Further studies by the research team
indicated that an even higher percentage – a total of 40% – have quality issues
linked to undeclared constituents. This includes eight samples that appear to
be adulterated with the flavonol glycoside rutin, or are composed of rutin
only. Of the milk thistle (Silybum marianum, Asteraceae) food supplement
products, 36% apparently did not contain any milk thistle. On the other hand,
all of the evening primrose (Oenothera biennis, Onagraceae)
products contained what was claimed on the label. The samples have been passed
on for further investigation to the Food Standards Agency (FSA), a governmental
department created to ensure food safety in the UK. However, the FSA has not
been in contact with the UCL investigators to date (Michael Heinrich e-mail
communication, September 11, 2015).
Comment: This investigation by the BBC–UCL
team into the authenticity of botanical products indicates that the quality of
such goods is of concern, and that the evaluation of such products is no longer
restricted to government agencies or academic institutions. Contrary to the
investigation by the New York Attorney General, the BBC chose an experienced
and reputable laboratory for the analysis of the products, leaving little to no
doubt about the accuracy of the findings. The results of this investigation
suggest that herbal products sold as THMs are manufactured to high quality
standards. However, the occurrence of adulterated products sold as food
supplements – a category different from THMs – is yet another indication that
there are unacceptable products on the market. Adulteration of ginkgo with
flavonol-rich extracts from other plants has been reported in a number of
instances,3-6 and therefore, may not come as a surprise. The authors
indicated that the number of tested milk thistle products was low, but
nevertheless, the relatively high number of adulterated products is indeed a
“startling result.”
References
1. Trust me –
I’m a doctor. Do herbal supplements contain what they say on the label? BBC website.
Available at: http://www.bbc.co.uk/programmes/articles/4hX30rMYkMv9YjMTH38MY6/do-herbal-supplements-contain-what-they-say-on-the-label. Accessed October
6, 2015.
2. UCL School
of Pharmacy. BBC two ‘Trust me I’m a doctor’ highlights quality problems of
unregulated food supplements. University College London (UCL) School of
Pharmacy website. Available at: https://www.ucl.ac.uk/pharmacy/pharmacy-news/food-supplements. Accessed October
6, 2015.
3. Tawab M,
Krzywon M, Schubert-Zsilavecz M. Dietary supplements containing ginkgo under
the microscope. [Article in German]. Pharm Ztg.
2010;20:62-67.
4. Chandra A, Li Y, Rana J, et al. Qualitative categorization of
supplement grade Ginkgo biloba leaf extracts for authenticity. J Funct Foods. 2011;3(2):107-114.
5. Wohlmuth H,
Savage K, Dowell A, Mouatt P. Adulteration of Ginkgo
biloba products and a simple method to improve its detection. Phytomedicine. 2014;21(6):912-918.
6. Avula B, Sagi S, Gafner S, et al. 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.
