Alzheimer’s disease is characterized by the accumulation of toxic proteins tau and amyloid beta in the brain, a fact that occurs years before those affected begin to manifest the first symptoms of cognitive decline. In fact, the latest drugs that have been developed to treat Alzheimer’s, such as lecanemab and donanemab, are aimed at eliminating the plaques formed by these proteins to slow the progression of dementia.
New research has discovered that compounds present in espresso coffee are capable of inhibiting tau protein aggregation. The tests that prove it are preliminary and have been carried out in vitro in the laboratory, but the results published in the Journal of Agricultural and Food Chemistry are great news because they can contribute to the development of new therapies that help combat this neurodegenerative disease.
Espresso coffee has a high concentration of caffeine and to prepare it, hot water is passed through coffee beans that have previously been ground to a very fine texture, thus producing a concentrated extract that sometimes serves as the base for other drinks, such as the Espresso Martini, a cold cocktail with vodka, or the Espresso Tonic, a fashionable combination between a shot of espresso with tonic water and ice, ideal for coffee lovers.
Some recent studies have suggested that drinking coffee might have a beneficial impact against neurodegenerative diseases such as Alzheimer’s, and while the exact mechanisms responsible for this effect are unknown, the tau protein is believed to play an important role. In healthy people, this protein helps stabilize brain structures, but when certain diseases develop, the proteins can clump together into fibrils. Some researchers point out that preventing this aggregation could alleviate symptoms.
Coffee compounds that act against toxic proteins
Mariapina D’Onofrio and colleagues at the University of Verona, Italy, wanted to see if compounds in espresso coffee could prevent tau aggregation in vitro. They extracted store-bought espresso beans and characterized their chemical composition using nuclear magnetic resonance spectroscopy. They chose caffeine and trigonelline –both alkaloids–, the flavonoid genistein, and theobromine, a compound also found in chocolate.
These molecules, along with the complete espresso extract, were incubated together with a shortened form of the tau protein for up to 40 hours. As the concentration of espresso, caffeine or genistein extract increased, the fibrils were shorter and did not form larger sheets, with the full extract giving the most spectacular results.
They found that the shortened fibrils were not toxic to cells and did not act as “seeds” for further aggregation. In other experiments, the researchers found that caffeine and espresso extract could bind to preformed tau fibrils. Although much more research is needed, the researchers say their preliminary in vitro findings could facilitate the search for or design of other bioactive compounds effective against neurodegenerative diseases, including Alzheimer’s.
Source: American Chemical Society
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