ARS | Publication request: Comparison of the phenolic component profiles of skullcap (Scutellaria lateriflora) and germander (Teucrium canadense and T. chamaedrys), a potentially hepatotoxic adulterant

Submitted to: Phytochemical Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 11, 2008
Publication Date: July 23, 2009
Citation: Lin, L., Harnly, J.M., Upton, R. 2009. Comparison of the phenolic component profiles of skullcap (Scutellaria lateriflora) and germander (Teucrium canadense and T. chamaedrys), a potentially hepatotoxic adulterant. Phytochemical Analysis. 20(4):298-306.

Interpretive Summary: Scutellaria laterifora, a common herb known as skullcap, has been subject to adulteration with various species of the botanical germander, Teucrium canadense and Teucrium chamaderys, which contain potentially hepatotoxic diterpenes. This results in a public safety concern with respect to the supply and use of this herbal product. We developed a chromatographic method that can differentiate between S. laterifora and 5 varieties of Teucrium, including those listed above. This method will allow herbal suppliers to select the correct plant materials and to produce quality products. In addition, the detailed information furnished by this method with regard to the phenolic components of these herbs will be helpful in establishing their health promoting benefits.

Technical Abstract: Scutellaria laterifora, commonly known as skullcap, is used as an ingredient in numerous herbal products. However, it has been occasionally adulterated with Teucrium canadense and T. chamaedrys, commonly known as germander, which contain potentially hepatotoxic diterpenes. Analytical methodologies to distinguish authentic S. laterifora from potentially adulterating Teucrium species are needed to ensure public safety; establishment of chromatographic profiles of the phenolic components of these plants can be used to differentiate between the genus and species. Scutellaria contained primarily flavonoids, while the major phenolic components of Teucrium were the phenylethanoids, verbascoside and teucrioside. Using verbascoside (for T. canadense) and teucrioside (for T. chamaderys) as markers, it was possible to detect as little as 5% Teucrium mixed with S. laterifora using UV and MS in the TIC mode. This limit of detection was based on the lowest detected content of the marker compounds. The main phenolic components of 4 Scutellaria and 2 Teucrium species were identified and the phenolic profile of each of them was clearly distinguished.