[PHNUTR-L] Compound in wine reduces levels of Alzheimer's disease-causing peptides

[Kathrynne Holden, MS, RD]

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Public release date: 3-Nov-2005
http://www.eurekalert.org/pub_releases/2005-11/asfb-ciw110305.php

Contact: Nicole Kresge
nkresge at asbmb.org
301-634-7415
American Society for Biochemistry and Molecular Biology

Compound in wine reduces levels of Alzheimer's disease-causing peptides

Bethesda, MD - A study published in the November 11 issue of the Journal 
of Biological Chemistry shows that resveratrol, a compound found in 
grapes and red wine, lowers the levels of the amyloid-beta peptides 
which cause the telltale senile plaques of Alzheimer's disease.

"Resveratrol is a natural polyphenol occurring in abundance in several 
plants, including grapes, berries and peanuts," explains study author 
Philippe Marambaud. "The polyphenol is found in high concentrations in 
red wines. The highest concentration of resveratrol has been reported in 
wines prepared from Pinot Noir grapes. Generally, white wines contain 1% 
to 5% of the resveratrol content present in most red wines."

One of the characteristic features of Alzheimer's disease is the 
deposition of amyloid-beta peptides in the brain. Philippe Marambaud and 
his colleagues at the Litwin-Zucker Research Center for the Study of 
Alzheimer's Disease and Memory Disorders in Manhasset, New York, 
administered resveratrol to cells which produce human amyloid-beta and 
tested the compound's effectiveness by monitoring amyloid-beta levels 
inside and outside the cells. They found that levels of amyloid-beta in 
the treated cells were much lower than those in untreated cells.

The researchers believe the compound acts by stimulating the degradation 
of amyloid-beta peptides by the proteasome, a barrel-shaped 
multi-protein complex that can specifically digest proteins into short 
polypeptides and amino acids.

However, eating grapes may not be a cure for Alzheimer's disease. "It is 
difficult to know whether the anti-amyloidogenic effect of resveratrol 
observed in cell culture systems can support the beneficial effect of 
specific diets such as eating grapes," cautions Marambaud. "Resveratrol 
in grapes may never reach the concentrations required to obtain the 
effect observed in our studies. Grapes and wine however contain more 
than 600 different components, including well-characterized antioxidant 
molecules. Therefore, we cannot exclude the possibility that several 
compounds work in synergy with small amounts of resveratrol to slow down 
the progression of the neurodegenerative process in humans."

Following up on their studies, Marambaud and his colleagues are trying 
to figure out how resveratrol exerts its effects in order to develop 
similar compounds to use in fighting Alzheimer's disease. "Our long-term 
goal is now to elucidate the exact molecular mechanisms involved in the 
beneficial properties of resveratrol as a necessary prerequisite to the 
identification of novel molecular targets and therapeutic approaches," 
says Marambaud. "The observation that resveratrol has a strong 
anti-amyloidogenic activity is a powerful starting point for screening 
analogues of resveratrol for more active and more stable compounds, a 
task in which our laboratory is actively involved. We have already 
obtained analogues of resveratrol that are 20 times more potent than the 
original natural compound. We are now aiming to find more stable 
analogues and to test them in vivo in mice."

Additional good news is that resveratrol may also be effective in 
fighting other human amyloid-related diseases such as Huntington's, 
Parkinson's and prion diseases. Studies by a group at the Institut 
National de la Santé et de la Recherche Médicale in Paris, France headed 
by Christian Néri have recently shown that resveratrol may protect 
neurons against amyloid-like polyglutamines, a hallmark of Huntington's 
disease.
-- 
Kathrynne Holden, MS, RD < fivestar at nutritionucanlivewith.com >
"Ask the Parkinson Dietitian"  http://www.parkinson.org/
"Eat well, stay well with Parkinson's disease"
"Parkinson's disease: Guidelines for Medical Nutrition Therapy"
http://www.nutritionucanlivewith.com/