Here's a botanical twist: The more stress that is placed on wild populations of St. John's wort, the more effective the plant might be in warding off human depression.
Plant pathologists from Cornell University and the U.S. Department of Agriculture (USDA) have found that hypericin (pronounced hi-PARIS-in), an active ingredient in St. John's wort (Hypericum perforatum) a popular herbal remedy for depression might be increased when the plant is attacked by predators such as insects.
"It appears to increase its own chemical arsenal to ward off attack from predators," says Donna M. Gibson, a USDA plant physiologist and Cornell adjunct professor of plant pathology. Gibson and Tara M. Sirvent, a Cornell plant pathology graduate student from Casper, Wyo., have developed a way to analyze the active chemical and other related compounds in the plant.
Sirvent and Gibson will present a poster, "Are hypericins involved in plant defense strategies of St. John's wort?" on Aug. 15 at the annual meeting of the American Phytopathological Society at the Hyatt Regency Hotel in New Orleans. The research was funded by the USDA's Agricultural Research Service and the agency's Foreign Agricultural Service.
The researchers dissolved the chemical components of the plant in a solution and separated them using a technique called high-performance liquid chromatography. This enabled the detection of individual compounds in the plant. Sirvent and Gibson examined wild populations and found plants that had been exposed to stress particularly attacks from insects had increased amounts of hypericin.
The level of hypericin determines the potency of St. John's wort sold over-the-counter, and as the plant's hypericin content increases so does its worth. While much of St. John's wort sold in stores is "wild-crafted" or picked from the wild commercially produced H. perforatum can fetch as much as $2,000 to $3,000 an acre.