Quercetin is a member of the flavonoid family found in apples, onions, tea, cranberries, blueberries, broccoli, cherries, cocoa, grapes, apricots, red wine, and kale. Quercetin may be one of the reasons why eating an apple a day is so good for you. High intake of quercetin may reduce your risk of lung cancer, asthma, respiratory conditions, heart attack, and cataracts, and new research suggests it may protect against Alzheimer’s disease, J. Agric. Food Chem., 52 (25), 7514 -7517, 2004. 10.1021/jf049243r S0021-8561(04)09243-X Web Release Date: November 10, 2004 stress-induced neurotoxicity, such as Alzheimer disease.
Protective Effects of Quercetin and Vitamin C against Oxidative Stress-Induced Neurodegeneration Ho Jin Heo and Chang Yong Lee* Department of Food Science and Technology, Cornell University, Geneva, New York 14456 Received for review May 11, 2004. Revised manuscript received September 8, 2004. Accepted September 14, 2004. This work was supported in part by the Postdoctoral Fellowship Program of the Korea Science and Engineering Foundation (2003) for H.J.H. at Cornell University. Abstract: Clinical trials of several neurodegenerative diseases have increasingly targeted the evaluation of various antioxidants’ effectiveness. The human diet contains several thousand phytochemicals, many of which have significant bioactivities. Vitamin C, a naturally occurring antioxidant, is known to reduce the risk of neurodegenerative disorders such as Alzheimer’s disease. Quercetin, one of the major flavonoids in some fruits and vegetables, has much stronger antioxidative and anticarcinogenic activities than vitamin C. Therefore, we investigated the protective effects of quercetin on hydroxy peroxide-induced neurodegeneration. To determine the protective effects, PC12 cells were preincubated with quercetin and vitamin C before H2O2 treatment for 2 h. Results showed that cell viability was clearly improved with quercetin, and quercetin showed a higher protective effect than vitamin C. Because oxidative stress is known to increase neuronal cell membrane breakdown, we further inve stigated lactate dehydrogenase and trypan blue exclusion assays. We observed that quercetin decreased oxidative stress-induced neuronal cell membrane damage more than vitamin C. These results suggest that quercetin, in addition to many other biological benefits, contributes significantly to the protective effects of neuronal cells from oxidative