Treatment with PMFs did not appear to have any effect on levels of HDL cholesterol, or good cholesterol, the researcher says. No negative side effects were seen in the animals that were fed the compounds, she adds. The researchers are currently exploring the compound's mechanism of action on cholesterol metabolism. They now suspect, based on early results in cell and animal studies, that it works by inhibiting the synthesis of cholesterol and triglycerides inside the liver.

A long-term human study of the effect of PMFs on high LDL cholesterol is now in progress. While drinking citrus fruits is full of health benefits, taking PMF supplements could be an easier way to lower cholesterol, since a person would have to drink 20 or more cups a day of orange or tangerine juice to have a therapeutic effect, Kurowska estimates.

KGK Synergize already has developed a nutrition supplement containing PMFs combined with a form of vitamin E that seems to enhance the compound's effect, according to Kurowska. Marketed as a cholesterol-lowering agent under the trade name SytrinolTM, the supplement recently became available in the U.S.

USDA's Citrus and Subtropical Products Laboratory in Winter Haven, Fla., and KGK Synergize Inc. provided funding for this study. acs/