A five-year-old research center dedicated to understanding and improving Echinacea and Hypericum perforatum (St. John's wort) has received $4.4 million in continuation funding from the National Institutes of Health. The renewal is for three years.
The Iowa Center for Research on Botanical Dietary Supplements at Iowa State University was created in 2002 by the NIH Office of Dietary Supplements. In addition to Iowa State, the center includes researchers at the University of Iowa, Yale University and the U.S. Department of Agriculture's North Central Regional Plant Introduction Station in Ames. A total of 27 researchers are involved (including 13 graduate students).
Echinacea and Hypericum are two of the nation's top selling herbal dietary supplements. Before the center was established, however, there were few scientific studies to understand the plants and their effect on human health.
Researchers in the Iowa Center for Research on Botanical Dietary Supplements work with well- defined plant material, identify the chemical profiles and key compounds that contribute to health benefits and define how they work. The center's primary goal is to improve understanding of the characteristics of the selected extracts that contribute to human health benefits and pave the way for optimizing the supplements.
During the past five years, center researchers have gained insight into the antiviral, anti-inflammatory and immune-boosting mechanisms of specific species of Echinacea, and the antiviral and anti-inflammatory activity of different populations of Hypericum, said Diane Birt, director of the center and distinguished professor of food science and human nutrition at Iowa State.
"In studying the nine different species of Echinacea, we found some species work better than others," Birt said. "This suggests that it will be possible to get an improved preparation that will enhance the supplement's benefit to human health."
Researchers also found that lipid-soluble compounds in Echinacea have appreciable anti-inflammatory activity. In Echinacea and Hypericum, water-soluble compounds, such as polyphenols, seem to contribute to the plant material's antiviral activity.
"This suggests that we're not going to find a single compound or even a subset of compounds that are responsible for health benefits," Birt said. "A complex chemical profile is contributing to the health effects, so it's more likely that we're moving toward improving these supplements rather than identifying chemicals for use as drugs. We are moving toward something like a fingerprint of the biologically active chemicals in the species."
In addition, the researchers have identified some specific compounds in Hypericum that provide much greater activity in combination than individually.