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The substitution and adulteration of skullcap with germander is a challenge
that has plagued the herb industry in the United States and elsewhere for over
30 years, and the problem still persists today, according to an article
in the recently released Winter 2012 issue of HerbalGram (#93).1
In the article, noted botanist, author, and photographer Steven Foster traces
the roots of common skullcap (Scutellaria lateriflora) adulterants,
which can include inferior-grade, mislabeled, and—occasionally—potentially
toxic substances. He continues with a discussion of modern cases of skullcap
adulteration and suggests methods of verifying the herb’s authenticity.
In a 2011 study featured in Analytical and Bioanalytical Chemistry, researchers
at USDA's Food Composition and Methods Development
Laboratory at the Beltsville Human Nutrition Research Center in Maryland found
that of 13 skullcap-containing dietary supplements tested (all of which were
purchased through the Internet) only 5 had a measurable amount
of true skullcap.2 Four supplements contained the potentially toxic
American germander (Teucrium canadense)—also referred to as wild
germander, wood sage, and wild basil—which has been a known adulterant of
skullcap products since the 1980s. Three supplements contained very low
concentrations of skullcap and one sample contained Chinese
skullcap (S. baicalensis) rather than the American species (S.
lateriflora).
Skullcap (also spelled “scullcap”)—which has been used for centuries as a mild
sedative and so-called “nerve tonic”—received international attention in the
1990s when some herbal products that claimed to contain it were associated with
several cases of liver dysfunction. Analyses later revealed the source of
toxicity to be European germander (T. chamaedrys), an additional known
skullcap adulterant.
Foster also wrote a short, non-bylined article in HerbalGram in 1985
alerting members of the industry about the skullcap-germander substitution
problem.3 In his new article, he describes the 2011 USDA study, as
well as a scientific paper from 1992 that first established germander as the
source of harm.
“A clear chronological relationship was established between ingestion of
germander and the onset of hepatitis,” Foster wrote. “Liver dysfunction was
reversed after use of germander products was discontinued.”
“In 2010 and 2011, I gave about a dozen speeches about adulteration problems in
the global herb market, and I referred to the skullcap-germander problem as an
example of a former problem,” said ABC Founder and Executive Director
Mark Blumenthal. “However, I was disappointed to read the report from the USDA
scientists this past summer showing that skullcap is still being
adulterated with germander!”
There are those who believe that skullcap and germander can look similar
because they are both members of the mint family (Lamiaceae or Labiatae).
Foster, and various herbal experts, believe that their physical characteristics
are distinct enough to warrant an accurate identification with the naked eye,
i.e., in the field.
According to an extensive quality control and therapeutic monograph on skullcap
(“Skullcap Aerial Parts, Scutellaria lateriflora L.”) produced by the
nonprofit American Herbal Pharmacopoeia (AHP), the relatively comparable
appearances of skullcap and other herbs can lead to accidental adulteration.4
The AHP monograph states, “Skullcap has historically been adulterated with
various species of the potential hepatotoxic germander (Teucrium canadense,
T. chamaedrys) due to morphological similarity between S.
lateriflora and T. canadense.”
Foster recommends using the AHP monograph as a guide for properly identifying
skullcap and germander species. “The most comprehensive and detailed
information source on the topic is the 2009 AHP skullcap monograph which
includes exhaustive information, illustrations, photographic images, and
chromatograms on authentication, morphological difference, and chemical differences
… of S. lateriflora, with an extensive discussion of adulterants.”
The recent HerbalGram article contains line drawings from the Missouri
Botanical Garden (MBG) of skullcap and germander parts in order to help differentiate
the plants, as well as Foster's beautiful 4-color photography of both plants.
The drawings are taken from a book on botanical identification produced by MBG
and ABC.5
The proper identification of herbal ingredients is paramount in helping prevent
adulteration and protecting consumers. As Foster concludes, “Persistent,
long-standing instances of adulteration and mislabeling of improperly
identified botanicals, such as in the instance of skullcap adulteration with T.
canadense, must be resolved to ensure that consumers get the herbal
products they expect.”
“In our view, all manufacturers of herbal dietary supplements and
herbal teas, in the US and globally, should read this article and the AHP
monograph on skullcap to ensure that they are taking adequate measures to
confirm that their skullcap raw material has not been confused with germander,”
said ABC's Blumenthal.
Foster's article is the second in a series of publications to come from the
ABC-AHP-NCNPR (National Center of Natural Products Research) Botanical
Adulterants Program,
a nonprofit educational consortium that includes numerous third-party
analytical laboratories and experts on herbs and herbal quality control. The
program is preparing a technical laboratory guide to assessing skullcap-germander
adulteration, as well as a variety of reviews and technical publications on the
adulteration of other herbs, herbal extracts, and essential oils. The
ABC-AHP-NCNPR Botanical Adulterants Program is an industry-sponsored,
self-regulated, educational initiative designed to help members of the global
herbal supply and finished products community obtain increased access to
information that can help ensure the accurate identity and quality of plant-based
ingredients and products.
—Tyler Smith
References
1. Foster S. The adulteration of skullcap (Scutellaria
lateriflora) with American germander (Teucrium canadense). HerbalGram. 2012:93;34-41.
Available here.
2. Sun J, Chen P. A flow-injection mass spectrometry fingerprinting method for
authentication and quality assessment of Scutellaria lateriflora-based
dietary supplements. Analytical and Bioanalytical Chemistry.
2011;401(5):1577-84.
3. Foster S. Scullcap substitution. HerbalGram. 1985:2(3);3.
4. Upton R, ed. American Herbal Pharmacopoeia and Therapeutic
Compendium: Skullcap Aerial Parts. Scotts Valley, CA: American Herbal
Pharmacopoeia; 2009.
5. Applequist W. The Identification of Medicinal Plants: A Handbook of the
Morphology of Botanicals in Commerce. Austin, TX, and St. Louis, MO:
American Botanical Council and Missouri Botanical Garden Press; 2006.
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