Natural health products containing Echinacea have been used by many patient populations and although there are reports of adverse effects with products containing Echinacea, few clearly characterized the nature of the product with respect to constituent content, the nature of the products and the mechanism underlying the interaction. The objective of this study was to examine blended and single-entity Echinacea products containing ground plant material or extracts in commercial capsules, herbal teas, tablets, tinctures and soft gel liquid-filled capsule formulations in an attempt to correlate biomarker constituent content and effects on cellular and subcellular parameters of interest. HPLC analysis indicated significant variability in the major biomarker constituent content in extracts from these Echinacea products. These extracts were also examined for their potential to affect cytochrome P450 CYP1A1/2, 2C9*1, 2C9*2, 2C19, 2D6, 3A4, 3A5, 3A7, and flavin-containing monooxygenase 3 (FMO3); CYP3A5-mediated metabolism, and expression of CYP3A4 and ABCB1. The extracts of some products were also examined for their effect cellular processes such as cell proliferation, nitric oxide formation as a marker of immunostimulatory capacity, and lactate dehydrogenase release as a marker for cell toxicity. The present study indicated that key Echinacea constituents varied widely within and between the products tested and that these levels did not correlate with the ability of these products to markedly affect the cellular processes studied.
©2011 Walter de Gruyter GmbH & Co. KG, Berlin/Boston
