Celery studies yield blood pressure boon.

When the father of University of Chicago medical student Quang T. Le developed a mild case of hypertension five years ago, he reached for an old Oriental remedy: celery. After eating a quarter pound of the ribbed vegetable every day for a week -- but not altering his diet in any other way -- he noted that his blood pressure dropped back into the normal range.

Now Le and William J. Elliott, a clinical pharmacologist at the University of Chicago, have found a possible explanation for this crunchy cure. They discovered that celery contains a chemical called 3-n-butyl phthalide, which relaxes the smooth-muscle lining of blood vessels, making them wider and thereby lowering blood pressure.

In experiments with normal rats, a dose of the phthalide compound equivalent to four stalks of celery in humans lowered blood pressure by an average of 13 percent, the researchers report. The same dose also pared the rats' cholesterol levels by 7 percent.

Le and Elliott determined that the phthalide compound works by lowering the concentration of stress hormones, or catecholamines, in the blood. These hormones cause blood vessels to constrict. In test-tube studies, the scientists found that the phthalide compound blocks the action of an enzyme called tyrosine hydroxylase, which the body used to produce catecholamines.

Elliott hopes that studies of 3-n-butyl phtalide will yield a more effective drug for hypertension. "Phthalide works through such a simple and direct mechanism to dilate vessels," he says. "Many of our current antihypertensive agents act through more roundabout mechanisms ... and can have troubling side effect, such as fainting, drowsiness or impotence."

However, he cautions people with high blood pressure against treating themselves by eating large amounts of celery. "While it may have helped Mr. Le," Elliott says, "eating more celery is not the recommended way to lower blood pressure." He notes that contains sodium, which can raise blood pressure, as well as other chemicals that can be toxic at high doses.