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 pote ntial role of the amyloid beta protein in Alzheimer's disease. It also disc usses the significance of amyloid beta in initiating the generation of part ially reduced oxygen species and points out their role in damaging essentia l macromolecules in the CNS which leads to neuronal dysfunction and loss. R ecently acquired experimental data links these destructive oxidative proces ses with some neurodegenerative aspects of Alzheimer's disease. The experim ental findings related to the free radical scavenging and antioxidative pro perties of melatonin are tabulated and its efficacy and the likely mechanis ms involved in its ability to reduce neuronal damage mediated by oxygen-bas ed reactive species in experimental models of Alzheimer's disease are summa rized. Besides the direct scavenging properties and indirect antioxidant ac tions 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.