Echinacea in Infection

Authors: BIRT, DIANE - IOWA STATE UNIVERSITY; Widrlechner, Mark; LALONE, CARLIE - IOWA STATE UNIVERSITY; WU, LANKUN - IOWA STATE UNIVERSITY; BAE, JAEHOON - IOWA STATE UNIVERSITY; SOLCO, AVERY - IOWA STATE UNIVERSITY; KRAUS, GEORGE - IOWA STATE UNIVERSITY; MURPHY, PATRICIA - IOWA STATE UNIVERSITY; WURTELE, EVE - IOWA STATE UNIVERSITY; LENG, QIANG - YALE UNIVERSITY; HEBERT, STEVEN - YALE UNIVERSITY; MAURY, WENDY - UNIVERSITY OF IOWA; PRICE, JASON - UNIVERSITY OF IOWA

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/13/2007
Publication Date: 2/7/2008
Citation: Birt, D.F., Widrlechner, M.P., Lalone, C.A., Wu, L., Bae, J., Solco, A.K., Kraus, G.A., Murphy, P.A., Wurtele, E.S., Leng, Q., Hebert, S.C., Maury, W.J., Price, J.P. 2008. Echinacea in Infection. American Journal of Clinical Nutrition. 87(suppl.):488S-492S.

Interpretive Summary: This report describes the Iowa Center for Research on Botanical Dietary Supplements. This Center studies the human-health effects of 3 botanical dietary supplements, Echinacea, St. John's wort, and Self-heal. It focuses on infection, with an emphasis on anti-viral, anti-inflammatory and anti-pain activity. Due to limited space, this report only reviews selected findings on Echinacea. One of the Center's strengths is its close relationship to the USDA-ARS North Central Regional Plant Introduction Station (NCRPIS), which maintains diverse collections of these plants. The Center relies on plant materials produced under defined conditions at the NCRPIS for its studies. We then describe 3 key areas of research findings produced by the Center's projects. The first examines the ability of Echinacea extracts to inhibit replication of HIV, the virus that causes AIDS. This work identified certain new constituents, in addition to one already known, that contribute to anti-viral activity without significant cell toxicity. The second examines assays using a widely recognized cell-culture system to measure the anti-inflammatory activity of Echinacea extracts. This work indicated that a class of chemicals called alkamides contributes to observed anti-inflammatory activity. The third examines the role of Echinacea in mediating pain, by testing the expression of a model pain receptor in frog oocytes. Significant bioactivity was reported, but could not be explained by known constituents. Experiments are now underway to help identify the bioactive constituent(s). These results should increase our understanding of the effects of Echinacea supplements on human health and can ultimately be used by health professionals to refine the use of these products, making them more safe and effective.

Technical Abstract: This report provides an overview of the organization and activities of the Iowa Center for Research on Botanical Dietary Supplements. This Center is designed to improve our understanding of the characteristics of Echinacea, Hypericum and Prunella that contribute to human health. It focuses on infection, with emphases on anti-viral, anti-inflammatory and anti-pain activity. Due to limited space, this report only discusses selected research findings related to Echinacea. One of the Center's strengths is its close relationship to the USDA-ARS North Central Regional Plant Introduction Station (NCRPIS), which maintains extensive collections of known-source Echinacea populations, representing all recognized taxa. The Center relies on plant materials produced under defined conditions at the NCRPIS for its bioactivity studies. Three key areas of research findings produced by Center projects are then described. The first summarizes experiments on Echinacea extracts to examine their ability to inhibit replication of the virus, HIV. This work identified polar constituents, other than cichoric acid (a known HIV inhibitor), that contribute to anti-viral activity without significant cytotoxicity. The second examines assays of anti-inflammatory activity of Echinacea extracts by measuring prostaglandin E2 (PGE2) accumulation in cells treated with and without lipopolysaccharide, a widely used screen based on a key event in inflammation. This work indicated that Echinacea alkamides contribute to observed anti-inflammatory activity. The third examines the role of Echinacea in mediating pain-receptor activity, by testing the effects of extracts in the transient expression of a pain receptor in frog oocytes. Significant bioactivity was reported, but could not be explained by either alkamides or polysaccharides. A combination of sub-fractionation of extracts and bioassays will be used to identify the bioactive constituent(s).