A combination of proteins and antioxidants doubles the anti-inflammatory properties in immune cells, according to a new paper published in the Journal of Agricultural and Food Chemistry.
Caffeic and chlorogenic acids are commonly found phenolic acids in plant-derived foods and beverages; their corresponding adducts with an amino acid called cysteine have been detected in coffee-containing beverages. Image credit: StockSnap.
Antioxidants known as polyphenols are found in humans, plants, fruits and vegetables.
This group of antioxidants is also used by the food industry to slow the oxidation and deterioration of food quality and thereby avoid off flavors and rancidity.
Polyphenols are also known to be healthy for humans, as they help reduce oxidative stress in the body that gives rise to inflammation.
In the new study, University of Copenhagen’s Professor Marianne Nissen Lund and colleagues investigated how polyphenols behave when combined with amino acids, the building blocks of proteins.
“In the study, we show that as a polyphenol reacts with an amino acid, its inhibitory effect on inflammation in immune cells is enhanced,” Professor Nissen Lund said.
“As such, it is clearly imaginable that this cocktail could also have a beneficial effect on inflammation in humans.”
“We will now investigate further, initially in animals. After that, we hope to receive research funding which will allow us to study the effect in humans.”
To investigate the anti-inflammatory effect of a combination of polyphenols and proteins, the researchers applied artificial inflammation to immune cells.
Some of the cells received various doses of polyphenols that had reacted with an amino acid, while others only received polyphenols in the same doses. A control group received nothing.
The authors observed that immune cells treated with the combination of polyphenols and amino acids were twice as effective at fighting inflammation as the cells to which only polyphenols were added.
“It is interesting to have now observed the anti-inflammatory effect in cell experiments,” said University of Copenhagen’s Dr. Andrew Williams.
“And obviously, this has only made us more interested in understanding these health effects in greater detail.”
“So, the next step will be to study the effects in animals.”
Previous studies by the scientists demonstrated that polyphenols bind to proteins in meat products, milk and beer.
In another study, they tested whether the molecules also bind to each other in a coffee drink with milk. Indeed, coffee beans are filled with polyphenols, while milk is rich in proteins.
“Our result demonstrates that the reaction between polyphenols and proteins also happens in some of the coffee drinks with milk that we studied,” Professor Nissen Lund said.
“In fact, the reaction happens so quickly that it has been difficult to avoid in any of the foods that we’ve studied so far.”
“Because humans do not absorb that much polyphenol, many researchers are studying how to encapsulate polyphenols in protein structures which improve their absorption in the body.”
“This strategy has the added advantage of enhancing the anti-inflammatory effects of polyphenols.”
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Jingyuan Liu et al. Phenolic Acid-Amino Acid Adducts Exert Distinct Immunomodulatory Effects in Macrophages Compared to Parent Phenolic Acids. J. Agric. Food Chem, published online January 30, 2023; doi: 10.1021/acs.jafc.2c06658
