ABSTRACT
The legend of “The Fountain of Youth” shows that rejuvenation, as well as anti-senescence that slows down the processes of aging to extend the maximum and mean lifespan, has been a human desire probably since humans •rst appeared on this planet (Gruman, 2003). Several theories have been proposed to explain the mechanism of senescence such as the mutation accumulation theory (Medawar, 1952), the antagonistic pleiotropy theory (Williams, 1957), and the disposable soma theory (Kirkwood and Holliday, 1979). Among such theories, the free radical theory is considered a convincing theory (Harman, 2003). Free radicals, for example, singlet oxygen, hydrogen peroxide, and hydroxide radicals that are produced during oxygen metabolism react with the polyunsaturated fatty acid residues of plasma membranes. Such interaction with the membrane results in oxidative damage to subcellular organelles that is of particular signi•cance for lysosomes, mitochondria, and the nuclear envelope (Goldstein et al., 1993).
