• 1
    Gupta S. Molecular steps of death receptor and mitochondrial pathways of apoptosis. Life Sci 2001; 69: 29572964.
  • 2
    Fadeel B, Orrenius S, Zhivotovsky B. Apoptosis in human disease: a new skin for the old ceremony? Biochem Biophys Res Commun 1999; 266: 699717.
  • 3
    Barisic K, Petrik J, Rumora L. Biochemistry of apoptotic cell death. Acta Pharm 2003; 53: 151164.
  • 4
    Henry-Mowatt J, Dive C, Martinou JC, James D. Role of mitochondrial membrane permeabilization in apoptosis and cancer. Oncogene 2004; 23: 28502860.
  • 5
    Bernardi P. Mitochondrial transport of cations: channels, exchangers and permeability transition. Physiol Rev 1999; 79: 11271155.
  • 6
    Halestrap AP, Mcstay GP, Clarke SJ. The permeability transition pore complex: another view. Biochimie 2002; 84: 153166.
  • 7
    Hardeland R, Fuhrberg B. Ubiquitous melatonin – presence and effects in unicells, plants and animals. Trends Comp Biochem 1996; 2: 2544.
  • 8
    Menendez-Pelaez A, Reiter RJ. Distribution of melatonin in mammalian tissues: the relative importance of nuclear versus cytosolic localization. J Pineal Res 1993; 15: 5969.
  • 9
    Martin M, Macias M, Escames G, Leon J, Acuña-Castroviejo D. Melatonin but not vitamins C and E maintains glutathione homeostasis in t-butyl hydroperoxide-induced mitochondrial oxidative stress. FASEB J 2000; 14: 16771679.
  • 10
    Reiter RJ, Tan DX. What constitutes a physiological concentration of melatonin? J Pineal Res 2003; 34: 7980.
  • 11
    Tan DX, Chen LD, Poeggeler B, Manchester LC, Reiter RJ. Melatonin: a potent endogenous hydroxyl radical scavenger. Endocrine J 1993; 1: 5760.
  • 12
    Reiter RJ, Tan DX, Manchester LC, EL-Sawi MR. Melatonin reduces oxidant damage and promotes mitochondrial respiration: implications for aging. Ann N Y Acad Sci 2002; 959: 238250.
  • 13
    Allegra M, Reiter RJ, Tan DX, Gentile C, Tesoriere L, Livrea MA. The chemistry of melatonin's interaction with reactive species. J Pineal Res 2003; 34: 110.
  • 14
    Witt-Enderby PA, Bennett J, Jarzynka MJ, Firestine S, Melan MA. Melatonin receptors and their regulation: biochemical and structural mechanisms. Life Sci 2003; 72: 21832198.
  • 15
    Acuña-Castroviejo D, Reiter RJ, Menendez-Pelaez A, Pablos MI, Burgos A. Characterization of high-affinity melatonin binding sites in purified cell nuclei of rat liver. J Pineal Res 1994; 16: 100112.
  • 16
    Becker-Andre M, Wiesenberg I, Schaeren-Wiemers N et al. Pineal gland hormone melatonin binds and activates an orphan of the nuclear receptor superfamily. J Biol Chem 1994; 269: 2853128534.
  • 17
    Carlberg C. Gene regulation by melatonin. Ann N Y Acad Sci 2000; 917: 387396.
  • 18
    Macias M, Escames G, Leon J et al. Calreticulin-melatonin: an unexpected relationship. Eur J Biochem 2003; 270: 832840.
  • 19
    Antolin I, Rodriguez C, Sainz RM et al. Neurohormone melatonin prevents cell damage: effect on gene expression for antioxidant enzymes. FASEB J 1996; 10: 882890.
  • 20
    Crespo E, Macias M, Pozo D et al. Melatonin inhibits expression of the inducible NO synthase II in liver and lung and prevents endotoxemia in lipopolysaccharide-induced multiple organ dysfunction syndrome in rats. FASEB J 1999; 13: 15371546.
  • 21
    Escames G, Leon J, Macias M, Khaldy H, Acuña-Castroviejo D. Melatonin counteracts lipopolysaccharide-induced expression and activity of mitochondrial nitric oxide synthase in rats. FASEB J 2003; 17: 932934.
  • 22
    Leon J, Macias M, Escames G et al. Structure-related inhibition of calmodulin-dependent neuronal nitric-oxide synthase activity by melatonin and synthetic kynurenines. Mol Pharmacol 2000; 58: 967975.
  • 23
    Leon J, Vives F, Crespo E et al. Modification of nitric oxide synthase activity and neuronal response in rat striatum by melatonin and kynurenine derivatives. J Neuroendocrinol 1998; 10: 297302.
  • 24
    Hlrata F, Hayaishi O, Tokuyama T, Seno S. In vitro and in vivo formation of two new metabolites of melatonin. J Biol Chem 1974; 249: 13111313.
  • 25
    Tan DX, Manchester LC, Burkhardt S et al. N1-acetyl-N2-formyl-5-methoxykynuramine, a biogenic amine and melatonin metabolite, functions as a potent antioxidant. FASEB J 2001; 15: 22942296.
  • 26
    Tan DX, Hardeland R, Manchester LC et al. Mechanistic and comparative studies of melatonin and classic antioxidants in terms of their interactions with the ABTS cation radical. J Pineal Res 2003; 34: 249259.
  • 27
    Acuña-Castroviejo D, Escames G, Carazo A, Leon J, Khaldy H, Reiter RJ. Melatonin, mitochondrial homeostasis and mitochondrial-related diseases. Curr Top Med Chem 2002; 2: 133151.
  • 28
    Martin M, Macias M, Escames G et al. Melatonin-induced increased activity of the respiratory chain complexes I and IV can prevent mitochondrial damage induced by ruthenium red in vivo. J Pineal Res 2000; 28: 242248.
  • 29
    Martin M, Macias M, Leon J, Escames G, Khaldy H, Acuña-Castroviejo D. Melatonin increases the activity of the oxidative phosphorylation enzymes and the production of ATP in rat brain and liver mitochondria. Int J Biochem Cell Biol 2002; 34: 348357.
  • 30
    Acuña-Castroviejo D, Martin M, Macias M et al. Melatonin, mitochondria, and cellular bioenergetics. J Pineal Res 2001; 30: 6574.
  • 31
    Sainz RM, Mayo JC, Uria H et al. The pineal neurohormone melatonin prevents in vivo and in vitro apoptosis in thymocytes. J Pineal Res 1995; 19: 178188.
  • 32
    Sainz RM, Mayo JC, Reiter RJ, Antolin I, Esteban MM, Rodriguez C. Melatonin regulates glucocorticoid receptor: an answer to its antiapoptotic action in thymus. FASEB J 1999; 13: 15471556.
  • 33
    Nava M, Romero F, Quiroz Y, Parra G, Bonet L, Rodriguez-Iturbe B. Melatonin attenuates acute renal failure and oxidative stress induced by mercuric chloride in rats. Am J Physiol Renal Physiol 2000; 279: F910F918.
  • 34
    Meki AR, Abdel-Ghaffar SK, EL-Gibaly I. Aflatoxin B1 induces apoptosis in rat liver: protective effect of melatonin. Neuroendocrinol Lett 2001; 22: 417426.
  • 35
    Mayo JC, Sainz RM, Uria H, Antolin I, Esteban MM, Rodriguez C. Melatonin prevents apoptosis induced by 6-hydroxydopamine in neuronal cells: implications for Parkinson's disease. J Pineal Res 1998; 24: 179192.
  • 36
    Chuang JI, Chen TH. Effect of melatonin on temporal changes of reactive oxygen species and glutathione after MPP+ treatment in human astrocytoma U373MG cells. J Pineal Res 2004; 36: 117125.
  • 37
    Thomas B, Mohanakumar KP. Melatonin protects against oxidative stress caused by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in the mouse nigrostriatum. J Pineal Res 2004; 36: 2532.
  • 38
    Pappolla MA, Sos M, Omar RA et al. Melatonin prevents death of neuroblastoma cells exposed to the Alzheimer amyloid peptide. J Neurosci 1997; 17: 16831690.
  • 39
    Zatta P, Tognon G, Carampin P. Melatonin prevents free radical formation due to the interaction between beta-amyloid peptides and metal ions [AI(III), Zn(II), Cu(II), Mn(II), Fe(II)]. J Pineal Res 2003; 35: 98103.
  • 40
    Lahiri DK, Chen D, GE YW, Bondy SC, Sharman EH. Dietary supplementation with melatonin reduces levels of amyloid beta-peptides in the murine cerebral cortex. J Pineal Res 2004; 36: 224231.
  • 41
    Li SP, Deng YQ, Wang XC, Wang YP, Wang JZ. Melatonin protects SH-SY5Y neuroblastoma cells from calyculin A-induced neurofilament impairment and neurotoxicity. J Pineal Res 2004; 36: 186191.
  • 42
    Cheung RT. The utility of melatonin in reducing cerebral damage resulting from ischemia and reperfusion. J Pineal Res 2003; 34: 153160.
  • 43
    Pei Z, Cheung RT. Melatonin protects SHSY5Y neuronal cells but not cultured astrocytes from ischemia due to oxygen and glucose deprivation. J Pineal Res 2003; 34: 194201.
  • 44
    Kilic E, Kilic V, Reiter RJ, Bassettic CL, Hermann DM. Prophylactic use of melatonin against focal cerebral ischemia in mice: role of endothelin converting enzyme-1. J Pineal Res, in press.
  • 45
    Andrabi SA, Sayeed I, Siemen D, Wolf G, Horn TF. Direct inhibition of the mitochondrial permeability transition pore: a possible mechanism responsible for anti-apoptotic effects of melatonin. FASEB J 2004; 18: 869871.
  • 46
    Winczyk K, Pawlikowski M, Karasek M. Melatonin and RZR/ROR receptor ligand CGP 52608 induce apoptosis in the murine colonic cancer. J Pineal Res 2001; 31: 179182.
  • 47
    Sainz RM, Mayo JC, Rodriguez C, Tan DX, Lopez-Burillo S, Reiter RJ. Melatonin and cell death: differential actions on apoptosis in normal and cancer cells. Cell Mol Life Sci 2003; 60: 14071426.
  • 48
    Wyllie AH, Kerr JF, Currie AR. Cell death: the significance of apoptosis. Int Rev Cytol 1980; 68: 251306.
  • 49
    Kerr JFR, Harmon BV. Definition and incidence of apoptosis: an historical perspective. In: Apoptosis: the Molecular Basis of Cell Death. TomeiLD, CopeFO eds. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY, 1991; pp. 529.
  • 50
    Ren Y, Savill J. Apoptosis: the importance of being eaten. Cell Death Differ 1998; 5: 563568.
  • 51
    Kroemer G, Dallaporta B, Resche-Rigon M. The mitochondrial death/life regulator in apoptosis and necrosis. Annu Rev Physiol 1998; 60: 619642.
  • 52
    Ankarcrona M, Dypbukt JM, Bonfoco E et al. Glutamate-induced neuronal death: a succession of necrosis or apoptosis depending on mitochondrial function. Neuron 1995; 15: 961973.
  • 53
    Bonfoco E, Krainc D, Ankarcrona M, Nicotera P, Lipton SA. Apoptosis and necrosis: two distinct events induced, respectively, by mild and intense insults with N-methyl-D-aspartate or nitric oxide/superoxide in cortical cell cultures. Proc Natl Acad Sci U S A 1995; 92: 71627166.
  • 54
    Leist M, Nicotera P. The shape of cell death. Biochem Biophys Res Commun 1997; 236: 19.
  • 55
    Yang J, Liu X, Bhalla K et al. Prevention of apoptosis by Bcl-2: release of cytochrome c from mitochondria blocked. Science 1997; 275: 11291132.
  • 56
    Susin SA, Zamzami N, Castedo M et al. Bcl-2 inhibits the mitochondrial release of an apoptogenic protease. J Exp Med 1996; 184: 13311341.
  • 57
    Suzuki Y, Imai Y, Nakayama H, Takahashi K, Takio K, Takahashi R. A serine protease, HtrA2, is released from the mitochondria and interacts with XIAP, inducing cell death. Mol Cell 2001; 8: 613621.
  • 58
    Du C, Fang M, Li Y, Li L, Wang X. Smac, a mitochondrial protein that promotes cytochrome c-dependent caspase activation by eliminating IAP inhibition. Cell 2000; 102: 3342.
  • 59
    Li LY, Luo X, Wang X. Endonuclease G is an apoptotic DNase when released from mitochondria. Nature 2001; 412: 9599.
  • 60
    Cain K, Bratton SB, Cohen GM. The Apaf-1 apoptosome: a large caspase-activating complex. Biochimie 2002; 84: 203214.
  • 61
    Hu Y, Ding L, Spencer DM, Nunez G. WD-40 repeat region regulates Apaf-1 self-association and procaspase-9 activation. J Biol Chem 1998; 273: 3348933494.
  • 62
    Sharpe JC, Arnoul T D, Youle RJ. Control of mitochondrial permeability by Bcl-2 family members. Biochim Biophys Acta 2004; 1644: 107113.
  • 63
    Hengartner MO. The biochemistry of apoptosis. Nature 2000; 407: 770776.
  • 64
    Luo X, Budihardjo I, Zou H, Slaughter C, Wang X. Bid, a Bcl2 interacting protein, mediates cytochrome c release from mitochondria in response to activation of cell surface death receptors. Cell 1998; 94: 481490.
  • 65
    Kim TH, Zhao Y, Barber MJ, Kuharsky DK, Yin XM. Bid-induced cytochrome c release is mediated by a pathway independent of mitochondrial permeability transition pore and Bax. J Biol Chem 2000; 275: 3947439481.
  • 66
    Fleury C, Mignotte B, Vayssiere JL. Mitochondrial reactive oxygen species in cell death signaling. Biochimie 2002; 84: 131141.
  • 67
    Droge W. Free radicals in the physiological control of cell function. Physiol Rev 2002; 82: 4795.
  • 68
    Mignotte B, Vayssiere JL. Mitochondria and apoptosis. Eur J Biochem 1998; 252: 115.
  • 69
    Lenaz G. The mitochondrial production of reactive oxygen species: mechanisms and implications in human pathology. IUBMB Life 2001; 52: 159164.
  • 70
    Hajnoczky G, Davies E, Madesh M. Calcium signaling and apoptosis. Biochem Biophys Res Commun 2003; 304: 445454.
  • 71
    Ghafourifar P, Richter C. Nitric oxide synthase activity in mitochondria. FEBS Lett 1999; 418: 291296.
  • 72
    Floreani M, Skaper SD, Facci L, Lipartiti M, Giusti P. Melatonin maintains glutathione homeostasis in kainic acid-exposed rat brain tissues. FASEB J 1997; 11: 13091315.
  • 73
    Othman AL, El-Missiry MA, Amer MA. The protective action of melatonin on indomethacin-induced gastric and testicular oxidative stress in rats. Redox Rep 2001; 6: 173177.
  • 74
    De Atenor MS, De Romero IR, Brauckmann E, Pisano A, Legname AH. Effects of the pineal gland and melatonin on the metabolism of oocytes in vitro and on ovulation in Bufo arenarum. J Exp Zool 1994; 268: 436441.
  • 75
    Reyes-Toso CF, Ricci CR, DeMignone IR et al. In vitro effect of melatonin on oxygen consumption in liver mitochondria of rats. Neuroendocrinol Lett 2003; 24: 341344.
  • 76
    Sewerynek E, Wiktorska J, Lewinski A. Effects of melatonin on the oxidative stress induced by thyrotoxicosis in rats. Neuroendocrinol Lett 1999; 20: 157161.
  • 77
    Yamamoto HA, Mohanan PV. Melatonin attenuates brain mitochondria DNA damage induced by potassium cyanide in vivo and in vitro. Toxicology 2002; 179: 2936.
  • 78
    Yamamoto HA, Mohanan PV. Ganglioside GT1 B and melatonin inhibit brain mitochondrial DNA damage and seizures induced by kainic acid in mice. Brain Res 2003; 964: 100106.
  • 79
    Karbownik M, Reiter RJ, Garcia JJ, Tan DX, Qi W, Manchester LC. Melatonin reduces rat hepatic macromolecular damage due to oxidative stress caused by delta-aminolevulinic acid. Biochim Biophys Acta 2000; 1523: 140146.
  • 80
    Karbownik M, Tan D, Manchester LC, Reiter RJ. Renal toxicity of the carcinogen delta-aminolevulinic acid: antioxidant effects of melatonin. Cancer Lett 2000; 161: 17.
  • 81
    Garcia JJ, Reiter RJ, Pie J et al. Role of pinoline and melatonin in stabilizing hepatic microsomal membranes against oxidative stress. J Bioenerg Biomembr 1999; 31: 609616.
  • 82
    Acuña-Castroviejo D, Escames G, Leon J, Carazo A, Khaldy H. Mitochondrial regulation by melatonin and its metabolites. Adv Exp Med Biol 2003; 527: 549557.
  • 83
    Ressmeyer AR, Mayo JC, Zelosko V et al. Antioxidant properties of the melatonin metabolite N1-acetyl-5-methoxykynuramine (AMK): scavenging of free radicals and prevention of protein destruction. Redox Rep 2003; 8: 205213.
  • 84
    Khaldy H, Escames G, Leon J, Bikjdaouene L, Acuña-Castroviejo D. Synergistic effects of melatonin and deprenyl against MTPP-induced mitochondrial damage and DA depletion. Neurobiol Aging 2003; 24: 491500.
  • 85
    Khaldy H, Escames G, Leon J, Vives F, Luna JD, Acuña-Castroviejo D. Comparative effects of melatonin, L-deprenyl, Trolox and ascorbate in the suppression of hydroxyl radical formation during dopamine autoxidation in vitro. J Pineal Res 2000; 29: 100107.
  • 86
    Acuña-Castroviejo D, Escames G, Macias M et al. Cell protective role of melatonin in the brain. J Pineal Res 1995; 19: 5763.
  • 87
    Bikjdaouene L, Escames G, Leon J et al. Changes in brain amino acids and nitric oxide after melatonin administration in rats with pentylenetetrazole-induced seizures. J Pineal Res 2003; 35: 5460.
  • 88
    Dabbeni-Sala F, Floreani M, Franceschini D, Skaper SD, Giusti P. Kainic acid induces selective mitochondrial oxidative phosphorylation enzyme dysfunction in cerebellar granule neurons: protective effects of melatonin and GSH ethyl ester. FASEB J 2001; 15: 17861788.
  • 89
    Okatani Y, Wakatsuki A, Reiter RJ. Melatonin protects hepatic mitochondrial respiratory chain activity in senescence-accelerated mice. J Pineal Res 2002; 32: 143148.
  • 90
    Okatani Y, Wakatsuki A, Reiter RJ, Miyahara Y. Hepatic mitochondrial dysfunction in senescence-accelerated mice: correction by long-term, orally administered physiological levels of melatonin. J Pineal Res 2002; 33: 127133.
  • 91
    Okatani Y, Wakatsuki A, Reiter RJ, Miyahara Y. Acutely administered melatonin restores hepatic mitochondrial physiology in old mice. Int J Biochem Cell Biol 2003; 35: 367375.
  • 92
    Okatani Y, Wakatsuki A, Enzan H, Miyahara Y. Protective effect of melatonin against mitochondrial injury induced by ischemia and reperfusion of rat liver. Eur J Pharmacol 2003; 469: 145152.
  • 93
    Rodriguez S, Leal C, Portilla E, Olivares N, Muniz J. Effect of exogenous melatonin on hepatic energetic status during ischemia/reperfusion: possible role of tumor necrosis factor-alpha and nitric oxide. J Surg Res 2001; 100: 141149.
  • 94
    Frandsen A, Schousboe A. Excitatory amino acid-mediated cytotoxicity and calcium homeostasis in cultured neurons. J Neurochem 1993; 60: 12021211.
  • 95
    Rego AC, Olivelra CR. Mitochondrial dysfunction and reactive oxygen species in excitotoxicity and apoptosis: implications for the pathogenesis of neurodegenerative diseases. Neurochem Res 2003; 28: 15631574.
  • 96
    Tymianski M, Charl Ton MP, Carlen PL, Tator CH. Source specificity of early calcium neurotoxicity in cultured embryonic spinal neurons. J Neurosci 1993; 13: 20852104.
  • 97
    Carriedo SG, Sensi SL, Yin HZ, Weiss JH. AMPA exposures induce mitochondrial Ca(2+) overload and ROS generation in spinal motor neurons in vitro. J Neurosci 2000; 20: 240250.
  • 98
    Castillo-Romero JL, Vives-Montero F, Reiter RJ, Acuña-Castroviejo D. Pineal modulation of the rat caudate-putamen spontaneous neuronal activity: roles of melatonin and vasotocin. J Pineal Res 1993; 15: 147152.
  • 99
    Castillo-Romero JL, Acuña-Castroviejo D, Escames G, Vives F. Age-related changes of neuronal responsiveness to melatonin in the striatum of sham-operated and pinealectomized rats. J Pineal Res 1995; 19: 7986.
  • 100
    Escames G, Acuña-Castroviejo D, Vives F. Melatonin-dopamine interaction in the striatal projection area of sensorimotor cortex in the rat. Neuroreport 1996; 7: 597600.
  • 101
    Escames G, Acuña-Castroviejo D, Leon J, Vives F. Melatonin interaction with magnesium and zinc in the response of the striatum to sensorimotor cortical stimulation in the rat. J Pineal Res 1998; 24: 123129.
  • 102
    Escames G, Macias M, Leon J et al. Calcium-dependent effects of melatonin inhibition of glutamatergic response in rat striatum. J Neuroendocrinol 2001; 13: 459466.
  • 103
    Smith IF, Plant LD, Boyle JP, Skinner RA, Pearson HA, Peers C. Chronic hypoxia potentiates capacitative Ca2+ entry in type-1 cortical astrocytes. J Neurochem 2003; 85: 11091116.
  • 104
    Jou MJ, Peng TI, Reiter RJ, Jou SB, Wu HY, Wen ST. Visualization of the antioxidative effects of melatonin at the mitochondrial level during oxidative stress-induced apoptosis of rat brain astrocytes. J Pineal Res 2004; 32: 5560.
  • 105
    Kilic E, Kilic U, Yulug B, Hermann DM, Reiter RJ. Melatonin reduces disseminate neuronal death after mild focal ischemia in mice via inhibition of caspase-3 and is suitable as an add-on treatment to tissue-plasminogen activator. J Pineal Res 2004; 36: 171176.
  • 106
    Park JW, Youn YC, Kwon OS, Jang YY, Han ES, Lee CS. Protective effect of serotonin on 6-hydroxydopamine- and dopamine-induced oxidative damage of brain mitochondria and synaptosomes and PC12 cells. Neurochem Int 2002; 40: 223233.
  • 107
    Kwak CS, Mun KC, Suh SI. Production of oxygen free radicals and of hemolysis by cyclosporine. Transplant Proc 2002; 34: 26542655.
  • 108
    Xu M, Ashraf M. Melatonin protection against lethal myocyte injury induced by doxorubicin as reflected by effects on mitochondrial membrane potential. J Mol Cell Cardiol 2002; 3: 7579.
  • 109
    Hoijman E, Rocha Viegas L, Keller Sarmiento MI, Rosenstein RE, Pecci A. Involvement of Bax protein in the prevention of glucocorticoid-induced thymocytes apoptosis by melatonin. Endocrinology 2004; 145: 418425.
  • 110
    Scott AE, Cosma GN, Frank M, Wells RL, Gardner HS, Jr Disruption of mitochondrial respiration by melatonin in MCF-7 cells. Toxicol Appl Pharmacol 2001; 171: 149156.
  • 111
    Carampin P, Rosan S, Dalzoppo D, Zagotto G, Zatta P. Some biochemical properties of melatonin and the characterization of a relevant metabolite arising from its interaction with H2O2. J Pineal Res 2003; 34: 134142.
  • 112
    De Almeida EA, Martinez GR, Klitzke CF, De Medeiros MH, Di Mascio P. Oxidation of melatonin by singlet molecular oxygen (O2(1O2) produces N1-acetyl-N2-formyl-5-methoxykynurenine. J Pineal Res 2003; 35: 131137.
  • 113
    Rozov SV, Filatova EV, Orlov M et al. N1-acetyl-N2-formyl-5-methoxykynuramine is a product of melatonin oxidation in rats. J Pineal Res 2003; 35: 245250.
  • 114
    Hardeland R, Poeggeler B, Niebergall R, Zelosko V. Oxidation of melatonin by carbonate radicals and chemiluminescence emitted during pyrrole ring cleavage. J Pineal Res 2003; 34: 1725.
  • 115
    Lopez-Burillo S, Tan DX, Rodriguez-Gallego V et al. Melatonin and its derivatives cyclic 3-hydroxymelatonin, N1-acetyl-N2-formyl-5-methoxykynuramine and 6-hydroxymelatonin reduce DNA oxidative damage induced by Fenton reagents. J Pineal Res 2003; 34: 178184.