ABSTRACT
Melatonin (MT) is secreted by the pineal gland and has obvious biological rhythmicity including circadian, season rhythm and life rhythm (aging clock). The reduction of MT secretion is related to body aging, particularly in close relation to brain aging. The hypothesis of aging is involved in pineal calcification, biological clock, neuro-en-docrinoimmunology, and free radical damage. MT is an endogenous free radical scavenger, may anto-gonize the attack of hydroxyl free radical ( ?OH)on organism and glutamate (Glu) excitotoxicity, and has a potent protective effect of central nervous system. In vivo studies showed that the food restriction and exogenous MT could obviously prolong life, postpone aging, and reduce the chances of age-related diseases. Investigating of MT anti-aging effect shows a vast prospect.