When Lee and co-author Ho Jin Heo, a visiting fellow at Cornell, looked at quercetin they found that it appeared to be the main agent responsible for the beneficial effect. In fact, they found quercetin works even better in protecting nerve cells against hydrogen peroxide than vitamin C, a naturally occurring antioxidant known to help prevent cell and tissue damage from oxidation. Quercetin is primarily found in apples, berries and onions.
This study, which appeared online recently, will be published in the December issue of the Journal of Agricultural and Food Chemistry .
The two studies build on Lee's 2002 findings that quercetin has stronger anti-cancer activity than vitamin C, and his 2000 findings that phytochemicals in apples have stronger anti-oxidant protective effects than vitamin C against colon and liver cancer cells.
Other studies have found that phytochemicals are associated with a reduced risk of cancer, heart disease and diabetes, and that they fight not only cancer but also bacterial and viral infections. In addition, they are anti-allergenic and anti-inflammatory.
Although Lee stresses that his studies were conducted in the laboratory, not in clinical trials with humans, he has no hesitation in recommending more apples in the diet as well as other fresh fruits and vegetables. "Indeed, I have a reason to say an apple a day keeps the doctor away," he says.
The researchers used red delicious apples grown in New York state to provide the extracts to study the effects of phytochemicals. Lee said that all apples are high in the critical phytonutrients and that the amount of phenolic compounds in the apple flesh and in the skin vary from year to year, season to season and from growing region to growing region.
The study on apple phenolics, which was co-authored by Heo and D.O. Kim, a postdoctoral researcher at Cornell, as well as S.J. Choi and D.H. Shin at Korea University, was supported in part
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Contact: Susan S. Lang
SSL4@cornell.edu
607-255-3613
Cornell University News Service
17-Nov-2004