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Title: YEAR-AND-A-HALF OLD, DRIED ECHINACEA SPP. ROOTS RETAIN CYTOKINE-MODULATING CAPABILITIES IN AN IN VITRO HUMAN OLDER ADULT MODEL OF INFLUENZA VACCINATION

Author
item SENCHINA, DAVID - IOWA STATE UNIVERSITY
item WU, LANKUN - IOWA STATE UNIVERSITY
item FLINN, GINA - IOWA STATE UNIVERSITY
item KONOPKA, DEL - IOWA STATE UNIVERSITY
item McCoy, Joe Ann
item Widrlechner, Mark
item KOHUT, MARIAN - IOWA STATE UNIVERSITY

Submitted to: Planta Medica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/13/2006
Publication Date: 10/13/2006
Citation: Senchina, D.S., Wu, L., Flinn, G.N., Konopka, D.N., Mccoy, J.H., Widrlechner, M.P., Kohut, M.L. 2006. Year-and-a-half old, dried Echinacea spp. roots retain cytokine-modulating capabilities in an in vitro human older adult model of influenza vaccination. Planta Medica. 72:1207-1215.

Interpretive Summary: Extracts prepared from aged Echinacea (purple coneflower) roots have been used to prevent or treat upper respiratory infections, as they have been thought to stimulate the human immune system. But the effects of long-term (> 1 year) dry storage on how these roots affect human immune responses, especially the production of cytokines (key factors in the immune response), are unknown. Our experiment was based on an adult model of influenza vaccination. Blood was collected from people six months after they were vaccinated, and cells were stimulated in the laboratory with two Type A influenza viruses and alcoholic extracts prepared from roots of seven different Echinacea species, that were stored dried for 16 months before being processed. The treated cell cultures were assayed for three cytokines important in the human immune response to viral infection. Four species (E. angustifolia, purpurea, simulata, tennesseensis) augmented one of the cytokines (interleukin-10), diminished another (interleukin-2), and had no effect on a third (interferon-gamma). Echinacea pallida suppressed production of all cytokines, and E. paradoxa and E. sanguinea behaved similarly, although to a lesser extent. These results indicate that Echinacea roots stored for 16 months maintain their ability to modulate human immune responses. This is also consistent with previous research that indicates that extracts from various Echinacea species differ in their patterns of immune modulation. These results should be valuable to virologists and immunologists in clarifying the wide range of reported immunological responses to Echinacea and to herbal practitioners in their selection of Echinacea species.

Technical Abstract: Alcohol tinctures prepared from aged Echinacea roots are taken to prevent or treat upper respiratory infections, as they are purported to stimulate immunity in this context. But the effects of long-term (> 1 year) dry storage on the ability of these roots to modulate human cytokine production are unknown. Using a human adult model of influenza vaccination, we collected peripheral blood mononuclear cells from subjects six months post-vaccination and stimulated them in vitro with the two Type A influenza viruses used in the trivalent 2004-2005 vaccine with a 50% alcohol tincture prepared from roots of one of seven Echinacea species: E. angustifolia, pallida, paradoxa, purpurea, sanguinea, simulata, and tennesseensis. Before being processed into extracts, all roots were dried and stored under controlled conditions for 16 months. Cells were cultured for 48 hours; after incubation, supernatants were collected and assayed for interleukin-2, interleukin-10, and interferon-gamma production, cytokines important in immune response to viral infection. Four species (E. angustifolia, purpurea, simulata, tennesseensis) augmented IL-10 production, diminished IL-2, and had no effect on INF-gamma. Production of all cytokines was suppressed by Echinacea pallida; E. paradoxa and E. sanguinea behaved similarly, although to a lesser extent. The results of the bioactivity assays indicate that Echinacea roots stored for 16 months maintain cytokine-modulating capacities. Our data support previous research and suggest that extracts from different Echinacea species have different patterns of immune modulation; further, they suggest that certain species may be efficacious in the immune response to viral infection.