Ferric nitrilotriacetate induced DNA and protein damage: Inhibitory effectof a fermented papaya preparation

The carcinogen Fe-NTA catalyzes the hydrogen peroxide-derived production of free radicals and possibly acts through a mechanism involving oxidative st ress. Fermented papaya preparation (FPP) has been reported as a natural ant ioxidant able to prevent lipid peroxidation in vitro and in vivo. However, little is known about the antioxidant properties of FPP regarding iron-medi ated oxidative damage to DNA and proteins. In the present study FPP protect ed super coiled plasmid DNA against Fe-NTA plus H2O2 induced single and dou ble strand breaks. Similar protective effects of FPP were evident when huma n T-lymphocytes were challenged with Fe-NTA/H2O2 and DNA damage was determi ned using the Comet assay. Fe-NTA/H2O2 also induced fragmentation of bovine serum albumin (BSA) in vitro and depleted cellular GSH levels in lymphocyt es. BSA fragmentation and GSH depletion were dose-dependently counteracted by FPP. EPR spin trapping studies demonstrated that antioxidant propel-ties of FPP are related to both hydroxyl scavenging as well as iron chelating p roperties.