EMBARGOED FOR RELEASE UNTIL 4 PM ET, April 16, 2002
Green Tea Extract Polyphenol May Have a Protective Effect on Parkinson's Disease
Denver, Colo. -
Polyphenol, a potent antioxidant found in green tea, has already been shown to have protective effects on several disease processes, including some cancers and forms of heart disease. Researchers have now shown that green tea polyphenols may also have a protective effect on Parkinson''s disease, according to a study presented at the 54th Annual Meeting of the American Academy of Neurology. Previous studies indicate that green tea extracts may have protective effects on Parkinson''s disease in test animals, yet the underlying protective mechanisms were not clear. Today''s study demonstrates the possible mechanism by which polyphenol protects against Parkinson''s disease. The main pathologic and biochemical characteristic of Parkinson''s disease is the selective cell death of dopaminergic neurons in the midbrain called substantia nigra and marked decrease in dopamine neurotransmitter produced by these neurons. "We tested the levels of dopamine uptake density in a controlled study of mice and the protective effects on dopaminergic neurons against neurotoxin MPP+-induced injury before and after treatment with polyphenol," says study author Tianhong Pan, MD, PhD, of Baylor College of Medicine in Houston. "Our results indicate the mechanism, or action, of polyphenol is to inhibit the uptake of dopamine or MPP+ by blocking dopamine transporter (DAT), suggesting that its protective effect in Parkinson''s disease is its ability to block the DAT-dependent uptake of environmental neurotoxin." Clinical effects of polyphenol on human Parkinson''s disease patients remain to be studied. In addition to being a major component of green tea, polyphenol can also be found in a concentrated capsule form.