Department of Cellular and Structural Biology, The University of Texas Health Science Center, San Antonio, Texas 78229-3900, USA
Address for correspondence: Russel J. Reiter, Department of Cellular and Structural Biology, The University of Texas Health Science Center, 7703 Floyd Curl Drive, Mail Code 7762, San Antonio, TX 78229-3900. Voice: 210/567-3859; fax: 210/567-6948.
Reiter{at}uthscsa.edu
Ann. N.Y. Acad. Sci. 959: 238-250 (2002).
Melatonin has a number of properties as a consequence of which
it could be beneficial to animals as they age. Of particular
interest are its ubiquitous actions as a direct and indirect
antioxidant and free radical scavenger. Besides directly detoxifying
a variety of reactive oxygen and reactive nitrogen species,
at least one product that is formed as a result of these interactions
is also a potent free radical scavenger. Thus, the product that
is formed when melatonin detoxifies hydrogen peroxide, that
is,
N1-acetyl-
N2-formyl-5-methoxykynuramine is an efficient
scavenger, at least equivalent to melatonin itself. This antioxidant
cascade increases the ability of melatonin to resist oxidative
damage. Other actions of melatonin, such as stimulation of antioxidative
enzymes also improves its status as an antioxidant. Finally,
recent observations documenting melatonin's ability to stimulate
electron transport and ATP production in the inner-mitochondrial
membrane also has relevance for melatonin as an agent that could
alter processes of aging. These findings, coupled with diminished
melatonin production in advanced age, has prompted scientists
to consider melatonin in the context of aging. As of this writing
there is no definitive evidence to prove that melatonin alters
the rate of aging, although data relating to melatonin deferring
some age-related degenerative conditions is accumulating rapidly.
