In preliminary in vitro laboratory tests, researchers at the University of Verona in Italy have identified chemical compounds present in espresso coffee that are able to inhibit tau protein aggregation—an important process in Alzheimer’s disease pathology.
Nearly 75 percent of Americans drink coffee every day, making it one of the most popular beverages in the country. Despite its possible negative health consequences such as causing anxiety and insomnia, recent research has suggested that drinking coffee can have beneficial effects on neurodegenerative conditions including Alzheimer’s disease.
Investigating this hypothesis in the Journal of Agricultural and Food Chemistry, scientists have characterized the chemical make up of espresso shots using nuclear magnetic resonance spectroscopy, focusing on caffeine and trigonelline—chemicals known as alkaloids—as well as the flavonoids genistein and theobromine for their experiments.
In order to understand the chemical’s role in Alzheimer’s disease, the researchers incubated the compounds, along with the complete espresso extract with a form of the tau protein for up to 40 hours. The protein is well-known as a potential cause of Alzheimer’s disease by forming insoluble filaments that accumulate in the brain leading to neuronal cell death and cognitive decline.
According to the scientists, as the concentration of espresso extract, caffeine or genistein increased, tau fibrils became shorter and did not form larger sheets—normally responsible for neuronal degradation. Compared to the isolated chemicals, the espresso extract showed the most dramatic results.
“These findings are particularly interesting because caffeine could provide a structural template to treat tauopathies targeting tau fibrils or to design molecular probes with improved specificity and binding properties for the detection of pathological aggregates useful for the clinical diagnosis of tau-based diseases,“ the authors said in their publication.
In addition to having a shorter length after incubation, the researchers also found the tau fibrils to be non-toxic to cells. Moreover, the fibrils did not act as “seeds” for further tau protein aggregation. Further experiments showed that caffeine and espresso extract were also able to bind pre-formed tau fibrils, potentially preventing aggregation.
“In conclusion, we have presented a large body of evidence that espresso coffee, a widely consumed beverage, is a source of natural compounds showing beneficial properties in ameliorating tau-related pathologies. Our findings could pave the way for further investigation into the design of bioactive compounds in the prevention and treatment of tauopathies,” the authors concluded in their paper.
