Egg yolk peptides protect brain cells from oxidative stress

As the human lifespan increases, so too does the risk of developing neurological disorders such as Parkinson's disease, Alzheimer's disease, anxiety and depression. These disorders are often accompanied by an excess amount of reactive oxygen species, or ROS. ROS are generated in the body throughout normal processes and have their place in a functioning cellular ecosystem; however, when their numbers get too high, problems arise. Hyun-Dong Paik from Konkuk University and his team of researchers use short chains of amino acids found in egg yolk, phosvitin phosphopeptides, to assess the effects of consumable antioxidants in protection against the build-up of oxidative stress in human neuroblastoma cells.

Hyun-Dong Paik and his team's results were published in Food Science of Animal Products on July 1st, 2026.

Reactive oxygen species (ROS), such as hydrogen peroxide (H₂O₂), in excess can lead to oxidative-stress-induced cell death during metabolic processes, in turn having the potential to lead to mutation and protein damage, later leading to various diseases. While human bodies have ways of eliminating some of these oxidants through antioxidant enzymes like catalases, it is often an overwhelming and impossible job once these oxidants start to build up excessively. This is where external forms of antioxidants, taken in through diet or supplementation, can help the process.

Testing occurred on SH-SY-5Y cells using PPP from hydrolyzed, high-temperature mild-pressure (HTMP) treated chicken egg yolk. The hydrolyzing process breaks the large molecules into smaller ones that can more easily be absorbed by the cells. Different agents such as trypsin (T), Multifect 14L (M) and a combination of the two (TM) were studied, as well as a treatment using just the HTMP-treated material. Of these four, HTMP-TM proved itself to show the most promise in reducing ROS.

The results from the HTMP-TM treatment had the highest antioxidant activity as well as increased cell viability (up to 76.44% from 57.46% when pretreated with HTMP-TM four hours before H₂O₂ treatment) and reduced cell death in stressed SH-SY-5Y cells. This treatment method also exhibited reducing power (meaning PPPs reduce the amount of electron-donating happening, therefore reducing the "energy" allowing for unfavorable reactions to occur) and radical scavenging (finding and reducing free radicals, which are unstable and reactive, and can damage cells and DNA).

Other effects of PPPs include metal chelation, which binds metals in a stable ring for later safe removal from the body, and beta-carotene bleaching inhibition and lipid peroxidation inhibition, both of which are protective against oxidative stress. HTMP-TM treated PPPs show the most evidence of being both antioxidative and neuroprotective on SH-SY-5Y cells.

PPPs are promising functional ingredients against H₂O₂-induced neurotoxicity. However, more in vivo studies are needed to demonstrate the value of PPPs as value-added food/nutraceutical ingredients."

Hyun-Dong Paik, researcher at Konkuk University and author of the study

Additional work also needs to be done to determine the dosage, delivery route and safety of PPPs in humans and animals, as well as work on the functional activities of PPPs to continue understanding their place and function as a potential antioxidant and neuroprotective addition for the prevention of neurodegenerative diseases.

Ji-Eun Lee and Hyun-Dong Paik of the Department of Food Science and Biotechnology of Animal Resources at Konkuk University, Jae Hoon Lee of the Department of Food Science & Technology at Jeonbuk National University, Dong Uk Ahn of the Department of Animal Science at Iowa State University and Kee-Tae Kim of the Research Center at WithBio contributed to this research.

The National Institute of Food and Agriculture/USDA partially supported this work.