Stable nitroxides are potential antioxidant drugs. In this study, we have linked nitroxide to natural amino acids with the aim to improve therapeutic activity. The radical scavenging activities of two nitronyl nitroxide-amino acid conjugates (NNR and NNK) were evaluated in PC 12 cell survival assays. The NO scavenging activities of these compounds were confirmed in the acetylcholine-induced vasorelaxation assay. In addition, the protective effect of NNR was demonstrated in an in vivo rat model of hepatic ischemia-reperfusion (I/R) induced injury and oxidative change. Because NNR reduced hepatic I/R injury by minimizing oxidative stress, it might be possible to develop it into a possible therapeutic agent for hepatic I/R injury.