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PHENETIC COMPARISON OF SEVEN ECHINACEA SPECIES BASED ON IMMUNOMODULATORY
CHARACTERISTICS.
Senchina, David S. (Immunobiology Program, Department of Health and Human
Performance, Iowa State University, Ames, Iowa 50011-1160), Lex E. Flagel (Department
of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames,
Iowa, 50011-1020), Jonathan F. Wendel (Department of Ecology, Evolution, and
Organismal Biology, Iowa State University, Ames, Iowa, 50011-1020), Marian L.
Kohut (Immunobiology Program, Department of Health and Human Performance, Iowa
State University, Ames, Iowa 50011-1160, e-mail: mkohut@iastate.edu; Ph: 1-515-294-8364;
Fax: 1-515-294-8740).
The purpose of the present investigation was to compare
similarities and differences in immune response among Echinacea species, which
are commonly used to treat upper respiratory infections. The investigation involved
two components: acquisition of immunomodulatory data reported here for the first
time, and combined
phenetic analysis of these data along with previous reports. Experimental data
were obtained by stimulating human PBMC in vitro with extracts from Echinacea
spp. and assaying production of three cytokines (interleukin–1ß [IL–1ß],
interleukin–2 [IL–2], and tumor necrosis factor–x [TNF–x]).
Phenetic analyses were employed to compare responses across the entir edata
set, including UPGMA (Unweighted Pair Group Method with Arithmetic Mean) and
neighbor-joining methods. In the immune experiments conducted for this investigation,
E. angustifolia, E. paradoxa, E. purpurea, E. simulata, and E. tennesseensis
extracts significantly augmented IL–1 ß and TNF–x production,
whereas no extracts significantly modulated IL–2. All phenetic methods
produced similar dendrograms, revealing two species pairs (E. angustifolia +
E. simulata and E. pallida + E. sanguinea) where both species cluster tightly
and have similar immune-response profiles. These two species-pairs are maximally
dissimilar from each other. The remaining species (E. paradoxa, E. purpurea,
and E. tennesseensis) occupy intermediate positions in the dendrogram. Our results
suggest that Echinacea spp. act heterogeneously on immune function. The utility
of these data for science and industry is discussed.
Key Words: comparison, cytokine, Echinacea, PBMC, phenetic, taxonomy.
Economic Botany 60(3):
205–211, 2006.
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