Antioxidant therapies for neurodegenerative diseases: mechanisms, current trends, and perspectives

Over the last decades, the involvement of free radicals and oxidative stress in the molecular mechanisms related to ageing, cancer, atherosclerosis, neurodegenerative disorders, diabetes, and inflammatory diseases became increasingly clear. As a consequence, the interest on the potential therapeutic applications of antioxidants has also increase. Naturally occurring antioxidants as well as modified or synthetic compounds have been screened for biological activities that could be useful in the development of new therapies for diverse conditions. Research using in vitro (cell culture and chemical free radical-generating systems), in vivo (animal models), and in silico models as well as epidemiologic and different types of clinical studies have been conducted by a great number of researchers worldwide, in order to evaluate the possible therapeutic properties of compounds with antioxidant activity. However, despite the massive accumulation of evidence confirming the role of oxidants in several pathological conditions (especially cancer), the absolute majority of antioxidants developed for clinical use has been proven ineffective.