Antioxidant and Immune-Modulating Activities of Egg Yolk Protein Extracts

Egg yolk is widely used to extract lecithin;which is utilized in the food and cosmetics industry. After lecithin is removed;the rest of egg yolk is generated as a byproduct. Thus;it is necessary to properly utilize it. In this study;egg yolk protein extracts were produced using ethanol (EYE-E) and water (EYE-W). Their antioxidant and immunomodulatory effects were then evaluated. Antioxidant activities of EYE-E and EYE-W were determined using cellular antioxidant capacity (CAC) assay and comet assay. EYE-E and EYE-W showed significant (p<0.05) scavenging effects on intracellular reactive oxygen species (ROS) in a dose dependent manner. At a concentration of 50 μg/mL;EYE-W showed higher (p<0.05) antioxidant activity than EYE-E. EYE-E and EYE-W also exhibited protective effects against DNA damage caused by oxidative stress. After treatment with EYE-E and EYE-W;DNA damage level of 48.7% due to oxidative stress was decreased to 36.2% and 31.8% levels;respectively. In addition;EYE-E and EYE-W showed immunomodulatory effects by regulating Th1 cytokines (TNF-α and IL- 2) and Th2 cytokines (IL-10 and IL-4) in Balb/c mouse splenocytes. These data suggest that EYE-E and EYE-W could be used as functional food ingredients with excellent antioxidant and immunomodulatory activities in the food industry.