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Case Study: Scutellaria and Teucrium
By Rob McCaleb, February 2004
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In the late 1970s and 1980s, reports began appearing of liver damage from products containing North American skullcap, Scutellaria lateriflora. The first case involved a woman who had taken a combination product believed to contain mistletoe, motherwort, kelp, wild lettuce, and American skullcap. After taking the formula for several weeks, she developed a nausea, malaise, and a dull pain in the upper right abdomen, which was attributed to liver inflammation (hepatitis) with mistletoe as the suspected toxin. (Harvey and Colin-Jones, 1981). However, this view was challenged by others because European mistletoe is not hepatotoxic (Fletcher Hyde, 1981; Farnsworth and Loub, 1981). The mistletoe component was later reported to be absent from the herbal product in question (McIntyre, 1984). |
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| Another report described four women with hepatitis or jaundice after the use of herbal tablets containing skullcap. Liver biopsies revealed acute hepatitis in two of the patients, and their liver function returned to normal 2 to 3 months after discontinuing the herbs. A liver biopsy was unsuccessful in the third patient, but liver function returned to normal in 19 months. The fourth patient showed jaundice after ingesting approximately 30 tablets over a 3-week period. A liver biopsy revealed chronic aggressive hepatitis with advanced fibrosis.. Investigators suggested that, of several ingredients common to the products taken, American skullcap (S. lateriflora) and valerian were the most likely offenders, even though there were no reports to show that these ingredients can actually produce liver damage (MacGregor et al., 1989). |
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| Weight loss, jaundice, and hepatomegaly with elevated liver function tests were seen in a 56-year-old Australian woman. Liver biopsy demonstrated a chronic active hepatitis of unclear origin. The patient had taken three different herbal remedies in addition to her conventional medicines. The first herbal preparation reportedly contained mistletoe, the second one celery fruit, guaiacum, burdock root and sarsaparilla, and the third one valerian, skullcap (S. lateriflora), and passionflower. After stopping all medications with the exception of thyroxine, the patient improved and was discharged after 2 weeks (Weeks, 1989). |
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Norwegian workers have reported additional case reports of liver damage, even with fatal consequences. Some patients had been taking several herbal remedies, including skullcap (S. lateriflora), whereas others had used an herbal remedy in which skullcap was the only ingredient (Leander and Skogstrom, 1991; Moum et al., 1992). Herbal experts have pointed out that S. lateriflora may have been mistakenly identified as being hepatotoxic. S. lateriflora is known to have been adulterated with various species of Teucrium, some of which may be hepatotoxic. Tyler notes thatgermander (Teucrium spp.) was found in the skullcap products taken by people who experienced liver damage (Tyler and Foster, 1999). The adulteration of S. lateriflora is also documented by DeSmet.4
DeSmet cites an "...increasing number of case reports to suggest that the ingestion of skullcap containing preparations can induce hepatotoxic reactions." Yet in an appended clarification, he acknowledges the adulteration of skullcap with species of Teucrium. This adulteration, along with recent reports of hepatitis associated with Teucrium consumption, lead De Smet to conclude that it is "...unclear at the moment, whether the hepatotoxic effects that have been associated with preparations containing skullcap should be attributed to Scutellaria, Teucrium, or both."
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| Due to the prevalence of this adulteration with the North American specie, the Association of Official Analytical Chemists (AOAC) has published a method for detecting the presence of this compound (Gafner et al. 2003).5 No known hepatotoxicity has been confirmed for S. lateriflora, and the North American species of Teucrium (primarily T. canadensis) have also not been shown to be livertoxic. It is speculated that European herbal product companies began substituting European Teucrium species for skullcap, including T. chamaedrys which contains hepatotoxic pyrrolizidine alkaloids and has been investigated for hepatoxicity including fatalities.6 The above information is included to clarify a potential point of confusion. Despite the existence of these few reports of “skullcap” hepatotoxicity, these episodes were probably caused by substitution with hepatotoxic Teucrium species. |
4 De Smet, P.A.G.M. et al., eds. 1993. Adverse Effects of Herbal Drugs 2. New York: Springer-Verlag. 5 Gafner S, Bergeron C, Batcha LL, Angerhofer CK, Sudberg S, Sudberg EM, Guinaudeau H and Gauthier R. Analysis of Scutellaria lateriflora and its Adulterants Teucrium canadense and Teucrium chamaedrys by LC-UV/MS, TLC, and Digital Photomicroscopy. Journal of AOAC International. May/June 2003 86 (3) 449-622 6 Larrey D, Vial T, Pauwels A, Castot A, Biour M, David M, Michel H. Hepatitis after germander (Teucrium chamaedrys) administration: another instance of herbal medicine hepatotoxicity. Ann Intern Med. 1992 Jul 15;117(2):129-32.
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