COMPOSITION AND BIOACTIVITY OF THREE ECHINACEA SPECIES
Cynthia A. Wenner1, Nadia Felicia1, Masa Sasagawa1, Dean Gray2, Gowsala Sivam1. 1Bastyr University Research Institute, Kenmore, WA; 2Herb Pharm, Inc., Williams, OR
Echinacea is one of the top-selling herbal remedies available over the counter in the U.S. and has reported effectiveness combating upper respiratory infections through its actions on the immune system. Several different Echinacea preparations, including different plant part extracts from different species are available on the market. The hypothesis of this study is that differences in observed biological activities of Echinacea species will correlate with differences in constituent composition. Investigation of the correlation between constituent composition of three different Echinacea species and immunomodulatory activity is currently underway to better elucidate their actions and potential for clinical application. Ethanol extracts (80:20 ethanol:water v/v) of dried roots of three wild-harvested Echinacea species, E. purpurea, E. pallida and E. angustifolia, were prepared. The known phenolic compounds of the extracts were fingerprinted and quantitated using High Pressure Liquid Chromatography. Effects of these extracts on different immune cell lines are under investigation. Jurkat E6-1 T lymphocytic leukemic cells were stimulated with phytohemagglutinin (PHA) and phorbal 12-myristate 13-acetate (PMA) alone or in the presence of Echinacea or extract vehicle control. IL-2 production at 6, 12 and 24 hours was measured by enzyme-linked immunosorbent assay (ELISA). Preliminary data show that root extracts from each of the three Echinacea species significantly depressed IL-2 production in PHA/PMA-stimulated Jurkat cells in comparison to the vehicle control. Experiments are currently underway to assess whether this IL-2 suppression correlates with effects of Echinacea extracts on proliferation or cytotoxicity of Jurkat cells, and if this effect is induced in other T cell lines or T cells isolated from human peripheral blood.
