The invention relates to compounds and compositions to treat some neurodegenerative diseases. In some embodiments, the invention relates to an antioxidant comprising a selenium atom and nitroxide group. In further embodiments, the antioxidant comprises peroxidase and superoxide dismutase activity. In some embodiments, the antioxidants are effective in treating neurodegenerative diseases including, but not limited to, Alzheimer's disease, Parkinson's disease, or multiple sclerosis. In additional embodiments, the invention relates to using compounds disclosed herein as free radical electromagnetic imaging agents.