Melanin nanoparticles: Antioxidant activities and effects on γ-ray-induced DNA damage in the mouse.

The radioprotective and antioxidant activities of melanin nanoparticles (MNP) were investigated in Chinese hamster ovary (CHO) cells in vitro and BALB/C mice in vivo. The endpoints measured were cell viability, superoxide dismutase (SOD) enzyme activity, malondialdehyde (MDA) levels, DNA damage (comet assay), and histopathological examination of tissues. Irradiated groups showed decreased SOD activity and increased MDA levels. Irradiation caused a 3-10-fold increase in comet parameters such as % tail DNA. Treatment with MNP protected cells from DNA damage and death, restored SOD activity, and decreased MDA production. Synthetic MNPs have both antioxidant and radioprotective activities.