‘Polyphenols play a key role in the health benefits of wine by acting as antioxidants that prevent cell damage, but the other possible effects of these chemicals are not yet fully understood. The group led by Alois Jungbauer from the University of Natural Resources and Life Sciences, Vienna in Austria, has shed light on this area by examining polyphenols in Austrian red wines.
They assessed polyphenol activity towards a receptor called PPAR-gamma, present in many tissues in the body, and which is primarily involved in the development of fat cells, in energy storage, and in modifying lipid and glucose levels in the blood, making it a key target for drugs for cardiovascular and metabolic diseases.
All the wines were rich in polyphenols, which are also found in green tea and ellagic acid found in many fruits. When the team ran PPAR-gamma binding assays, they found that not only did these compounds bind to the receptor, the wines contained enough of them to rival the activity of the potent drug rosiglitazone, which is used to treat type 2 diabetes.
One of the wines was a Blaufränkisch - a dark skinned, late ripening, spicy variety grape that is rich in tannins and containing particularly high polyphenol levels and is also grown in Austria. Merely 100 mL contained levels reportedly equivalent to about four times the daily dose of rosiglitazone,
Jungbauer says that tannin-rich red wines contain more polyphenols, but it is too early to come to any general conclusions about grape varietals yet. However, he suspects that environmental factors and wine technology have as much influence as the type of grape. He points out that grape tannin and oak tannin supplements are often used in wine technology as antioxidants, and are added to the fermented must. These extracts are rich in polyphenols and may also be a potent source of PPAR-gamma.
'Grape skin extracts have great potential, and although the influence of ethanol is not yet fully understood, I am confident that it will be possible to replace some synthetic compounds by plant extracts,' concludes Jungbauer.
Chi-Tang Ho, a food scientist at Rutgers School of Environmental and Biological Sciences, New Jersey, US, terms this study as an extremely exciting study and feels that it provides good experimental evidence for the potential anti-diabetic effect of drinking red wine in moderation.
"It's incredible. It's a really high activity. At first we were worried it was an artifact, but then we identified the compounds responsible in the wine," New Scientist quotes Jungbauer as saying. However, not all the anti-diabetic compounds may be absorbed by the body and the fact that it also contains ethanol means it may add to the calories intake.
Jungbauer and his team will now work on measuring the metabolic effects of the wine compounds on healthy people.
Tags: Diabetes, Jungbauer, polyphenol, Blaufränkisch, Rosiglitazone, Veronique Cheynier, Montpellier, Chi-Tang Ho, Rutgers, Vienna, Austria
It would have been interesting to see the effect of the Tannat grape which is common in Uruguay and South West of France and is extremely high in Polyphenols-editor |