Quercetin, a bioflavonoid found in many fruits and vegetables, may protect nerve cells from the oxidative damage associated with conditions like Alzheimer's disease, report researchers at Cornell University in the December 2004 issue of the Journal of Agricultural Food Chemistry.
The human central nervous system is highly sensitive to oxidative stress, making it vulnerable to neurodegenerative diseases such as age-related cognitive decline and Alzheimer's disease. Scientists have studied many antioxidants, including vitamin C, as potential therapeutic agents against neurodegeneration. Cornell researchers demonstrated that quercetin is better than vitamin C at protecting nerve cells from damage due to oxidative stress.
In the study, scientists used a cell line with nerve-like characteristics. The cells were pre-incubated for two hours with either quercetin or vitamin C, and the treated cells were then exposed to hydrogen peroxide, a significant inducer of oxidative damage. Quercetin was more protective than vitamin C, and less cell death occurred in the quercetin-treated cells than in those treated with vitamin C. Quercetin also protected nerve cell membranes more than did vitamin C. This is significant because the researchers believe that loss of cell membrane integrity contributes to neurotoxicity. Larger doses of quercetin or vitamin C conferred greater protection from oxidative stress.
These findings suggest that quercetin offers significant antioxidant protection to nerve cells. Quercetin may therefore help to prevent or manage Alzheimer's disease and other neurodegenerative conditions associated with nerve cell oxidative stress.
Heo HJ, Lee Cy. Protective effects of quercetin and vitamin C against oxidative stress-induced neurodegeneration. J Agric Food Chem. 2004 Dec 15;52(25):7514-7.