Natural Melanin From Silky Fowl (Gallus gallus domesticus Brisson): Characterization and Protection of Caco‐2 Cells From Oxidative Stress via the Akt/Nrf2 Pathway

Silky fowl, a unique chicken breed, exhibits black skin, meat, and bones due to the presence of natural melanin pigments. In our study, melanin from silky fowl (MSF) was isolated using an enzymatic extraction procedure and identified as a unique natural antioxidant. Results showed that H 2 O 2 triggered oxidative stress, but the internalization of MSF exerted protective effect on Caco‐2 cells. MSF notably enhanced viability and reduced apoptosis in oxidative damage Caco‐2 cells. In addition, MSF led to a notable antioxidant effect by increasing the activities of endogenous enzymes, such as SOD, CAT, and GSH‐Px, while reducing intracellular reactive oxygen species (ROS) levels, as well as LDH and MDA contents. It also enhanced the barrier function of Caco‐2 cells and upregulated the expression of tight junction proteins. Mechanistically, MSF reduced the p‐Akt/Akt ratio and activated the nuclear factor erythroid 2–related factor 2 (Nrf2) pathway, thus promoting cell survival under oxidative stress. These findings suggest that silky fowl melanin exhibits potent antioxidant properties and holds potential as a natural alternative to synthetic antioxidants in the functional food industry.