St. John's Wort Collection Mined for Its Medicinal
Value By Jan
Suszkiw March 30, 2010
A unique collection of St. John's wort (Hypericum) curated by
Agricultural Research Service (ARS)
scientists in Ames, Iowa, is providing university collaborators with
genetically diverse, well-documented sources of this herb to use in studies
examining its medicinal potential.
In collaboration with
Widrlechner, a horticulturist with the ARS crop genebank at the
Central Regional Plant Introduction Station in Ames, scientists from the
Center for Research on
Botanical Dietary Supplements (CRBDS) are screening 180 germplasm
accessions of St. John's wort for biologically active compounds. Some may be
worth evaluating further in clinical trials for their potential to combat viral
infections, reduce inflammation or improve digestive health.
Established in 1948, the ARS Ames crop genebank curates more than
50,000 accessions of ornamental plants, maize, oilseeds, vegetables and other
crops, and provides them to researchers for many applications. Accessions with
medicinal or nutraceutical value include Echinacea (purple coneflower),
Hypericum, Prunella (self-heal) and Actaea racemosa (black
cohosh). ARS horticulturist
Qu curates the collection and Widrlechner coordinates its use for research
at CRBDS, one of six Botanical Research Centers funded by the
National Institutes of Health from 2005-2010.
The Hypericum collection at Ames was started in the 1990s and
today encompasses about 60 species collected from around the world. This
diversity has enabled investigations of genetic, environmental and
developmental factors affecting the quantity and quality of bioactive
compounds, as well as their modes of action.
Of particular interest is how these compounds interact, and whether
those interactions are critical to human health benefits. In a recent issue of
Biology, researchers noted that combinations of four compounds from St.
John's wort (amentoflavone, chlorogenic acid, pseudohypericin and quercetin)
were more effective at reducing inflammation in mouse macrophage assays than
when each was used alone.
Widrlechner's collaborators include
Hillwig, Jingqiang Wei,
Wurtele at Iowa State University;
Jeffrey Neighbors, David
Maury and Jason Price at the University of
Iowa; and Joe-Ann McCoy, formerly with ARS.
ARS is the principal intramural scientific research agency of the
U.S. Department of
Agriculture (USDA). The research supports the USDA priority of improving
human nutrition and health.