Eggplant Found to Have an Antioxidant Kick

By Rosalie Marion Bliss
January 8, 2004

Eggplant contains high levels of an antioxidant compound that may protect the body's cells against oxidative damage, according to studies by two Agricultural Research Service scientists. They found that chlorogenic acid, one of the most powerful antioxidants produced in plant tissues, was the predominant phenolic compound in nearly all the samples analyzed.

Phenolic acids are a simple class of antioxidant phenylpropanoid compounds. Plants produce many different phenylpropanoids to protect themselves against stress and infection.

Geneticist John R. Stommel of the ARS Vegetable Laboratory and plant physiologist Bruce D. Whitaker of the ARS Produce Quality and Safety Laboratory conducted the research. Both labs are part of the ARS Henry A. Wallace Beltsville (Md.) Agricultural Research Center. The scientists studied seven eggplant cultivars grown commercially in the United States, and a diverse collection of exotic and wild eggplant from other countries.

In addition to chlorogenic acid, the researchers found 13 other phenolic acids present at varying levels in the commercial cultivars. They also identified several phenolic compounds in two of the wild eggplant relatives that had never before been isolated from plants.

Extracting the compounds alone was challenging, as the fruit's flesh oxidizes quickly when it is cut and exposed to air. After extraction, the scientists used three analytical methods to separate, quantify and identify the eggplant phenolics.

The scientists are seeking to identify valuable traits worth introducing into popular commercial cultivars for health purposes. The work helps establish new breeding lines, which the commercial seed industry uses to develop finished varieties that benefit consumers.

Read more about this research in this month's issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture's chief scientific research agency.