Dr Michikatsu Sato, based at a government-funded alcohol R&D centre, has uncovered small peptides present in both red and white wines that inhibit the PEP enzyme, implicated in the pathology of Alzheimer's disease.
It is still unknown if these peptides can be extracted from wine and whether they have a preventative effect on the disease in humans. But the research, to be presented next month at the World Nutra conference in San Francisco, offers some hope for the increasing numbers of elderly with memory loss and Alzheimer's.
There are currently nearly 18 million people with dementia in the world, and the most common cause of this dementia is Alzheimer's disease. By 2025 this figure will rise to 34 million, with 71 per cent of these likely to live in developing countries.
The findings also support previous evidence that people who drink alcohol regularly have a lower risk of the disease and other types of senility.
Dr Sato's findings were triggered by the observation of large amounts of the amino acid L-proline in wine. The researcher and his colleagues theorized that an inhibitor of an enzyme called Prolyl EndoPeptidase (PEP), which selectively chops up specific proline-containing peptides and is found throughout the human body, could also be present in wine.
PEP digests brain hormones that are involved in learning and memory and may also generate amyloid protein, which accumulates in Alzheimer's patients.
Dr Sato has identified PEP inhibitors that are pentapeptides (composed of 5 amino acids in a chain) in several wines, with the greatest concentrations found in Merlot (California), Sauvignon Blanc (Bordeaux), and Pinot Noir. The pentapeptide was also detected in table grapes, and was found to be in the juice and pulp parts of grape berries.
Dr Sato carried out the work as head of the Wines and Spirits Research Institute of wine firm Mercian, where he worked until last year, and published his findings in the journal Bioscience, Biotechnology and Biochemistry (vol 67, pp 380-382).
He noted: "It is complicated to extract the pentapeptides from wine. Actually, we chemically synthesized the pentapetides as the standards."
"I think that pharmaceutical companies have been trying to synthesize thePEP inhibitors and testing the efficacy."