Air Date: Week of September 1, 2000

Studies have shown the amount of active ingredients in herbal medications can vary greatly. Now, research out of Cornell University may help to explain why that’s so for St. John’s Wort, the popular herb used in the treatment of depression.

Transcript

TOOMEY: St. John's Wort is a popular herbal remedy used to treat depression. Now comes word that a little stress on that plant may go a long way to relieve your anxiety. Studies have shown that the potency of St. John's Wort products can vary greatly from brand to brand and even pill to pill, and now scientists think they know why. Researchers at Cornell University have found when St. John's Wort is attacked by insects, the herb produces more of the active ingredient thought to alleviate depression. The scientists think this substance, hypericin , is part of the plant's arsenal of chemical defenses. They're also looking at how other factors, such as light, moisture, and altitude, affect hypericin levels. While much of St. John's Wort products are derived from wild-harvested plants, the herb is also grown commercially. A crop of St. John's Wort with a high level of hypericin fetches as much as $3,000 an acre. That's this week's health update. I'm Diane Toomey.