Dear Reader,
Once
again, we put a spotlight on authenticity issues in this newsletter and feature
a selection of different analytical approaches to determine the authenticity of
herbal ingredients. Issue # 21 includes data on commercial dietary supplement
products obtained by microscopy, DNA barcoding, high-performance thin-layer chromatography
(HPTLC), high-performance liquid chromatography with UV detection (HPLC-UV),
carbon isotope mass spectrometry, and proton nuclear magnetic resonance (1H
NMR) spectroscopy. It shows that the verification of herbal ingredient identity
is not a trivial matter, and that in many cases, as we have often emphasized, the
use of a number of orthogonal methods is necessary to have a robust quality
control protocol.
The measurement of carbon isotopes to detect the undeclared
admixture of nature-identical constituents made by chemical synthesis or by
fermentation appears to become more popular. The Regulatory Alerts section below details a case where
evidence was sent to the FDA and the FTC alleging the undeclared addition of
vitamin C obtained via fermentation to amla (Phyllanthus emblica) extracts. The report was based on
measuring the 13C/12C isotope ratio of the vitamin C by
mass spectrometry.
Using 14C
isotope mass spectrometry, the addition of synthetic curcumin to dietary
supplements containing turmeric (Curcuma
longa) root extracts was exposed. As part of the investigation, 14
turmeric products were sent to the contract analytical laboratory Beta Analytic
for 14C content measurements of curcumin. In addition, curcuminoid
concentrations were determined by HPLC-UV. Of the 14 products that were
analyzed in 2020, five contained curcumin that was made with petroleum-based
starting materials. Details of this investigation are provided in this issue’s Industry Alerts section.
The first summary in the Science Update section details the HPTLC analysis of
rhodiola (Rhodiola rosea) bulk
materials and dietary supplements sold in the Ukraine. Interestingly, R. rosea roots from different origins had
highly variable HPTLC fingerprints, making correct identification more
challenging. The three liquid rhodiola dietary supplements had fingerprints suggestive
of Rhodiola crenulata.
The
second review details an investigation into the quality of passionflower (Passiflora incarnata) extracts in seven
dietary supplements sold in Brazil. Using 1H NMR, four supplements
were found to lack the signals of the characteristic flavonol-C-glycosides in
passionflower herb.
Another
1H NMR-based investigation looked at the accuracy of labeling of 28
cinnamon spice and dietary supplement products available on the French market.
Four samples (two food products and two dietary supplements) labeled to contain
cinnamon (Cinnamomum verum) were
found to contain cassia (C. cassia),
and four cinnamon dietary supplements did not have any detectable 1H
NMR signals attributable to cinnamon constituents.
Using DNA barcoding, the authenticity of seven reishi (Ganoderma spp.) supplements was verified.
The authors of this paper intentionally distinguished between G. lucidum and G. lingzhi and classified all the seven reishi products as G. lingzhi, even if the taxonomy of reishi
is still debated, underscoring that ‘adulteration’ can be a matter of debate
due to a lack of taxonomic certainty.
The Science Update section
ends with a review of papers using botanical microscopy to assess the
authenticity of crude medicinal plant materials. Twenty-eight publications from
2005-2018 were included, showing that despite microscopy being considered an old
analytical technique, it provides pertinent and valuable information on the
quality of an herbal ingredient that may be missed when using modern chemical
and genetic methods of analysis.
We
hope that the information provided in the “Botanical
Adulterants Monitor” is of use for those in the quality control
and assurance, research, and development, and purchasing of herbal dietary
supplement manufacturers, and we encourage you to share the contents of this
newsletter with your colleagues.
All of
us at BAPP, including the American Botanical Council (ABC), the American Herbal
Pharmacopoeia (AHP), and the National Center for Natural Products Research
(NCNPR) at the University of Mississippi, hope that you, your family, friends,
and co-workers will have a happy holiday season, and wish you a healthy and
successful 2021.
Stefan
Gafner, PhD
Chief
Science Officer
American
Botanical Council
Technical
Director, ABC-AHP-NCNPR Botanical Adulterants Program
