An assessment of the antioxidant and the antiamyloidogenic properties of melatonin: implications for Alzheimer's disease.

This review summarizes recent advancements in our understanding of the potential role of the amyloid beta protein in Alzheimer's disease. It also discusses the significance of amyloid beta in initiating the generation of partially reduced oxygen species and points out their role in damaging essential macromolecules in the CNS which leads to neuronal dysfunction and loss. Recently acquired experimental data links these destructive oxidative processes with some neurodegenerative aspects of Alzheimer's disease. The experimental findings related to the free radical scavenging and antioxidative properties of melatonin are tabulated and its efficacy and the likely mechanisms involved in its ability to reduce neuronal damage mediated by oxygen-based reactive species in experimental models of Alzheimer's disease are summarized. Besides the direct scavenging properties and indirect antioxidant actions of melatonin, its ability to protect neurons probably also stems from its antiamyloidogenic properties. Melatonin is also unique because of the ease with which it passes through the blood-brain barrier.