Melatonin: a peroxyl radical scavenger more effective than vitamin E.
We have compared the peroxyl radical scavenger ability to melatonin with that of vitamin E, vitamin C and reduced glutathione (GSH). In the assay system, beta-phycoerythrin (beta-PE) was used as fluorescent indicator protein, 2-2'-azo-bis(2-amidinopropane)dihydrochloride as a peroxyl radical generator and the water soluble vitamin E analogue. Trolox, as reference standard. Results are expressed as oxygen radical absorbing capacity (ORAC(perox)) units, where 1 ORAC unit equals the net protection produced by 1 microM Trolox. A linear correlation of ORAC values with concentration (0.5-4 microM) of all the substances tested has been observed. However, on molar basis, the relative ORAC(perox) of Trolox, vitamin C, GSH and melatonin was 1:1.12:0:68:2.04, respectively. Thus, melatonin, which is a lipid-soluble compound, was twice more active than vitamin E, believed to be the most effective lipophilic antioxidant.
Pieri
C
C
Gerontological Research Department of I.N.R.C.A., Ancona, Italy.
Marra
M
M
Moroni
F
F
Recchioni
R
R
Marcheselli
F
F
D000578:Amidines; D001205:Ascorbic Acid / Q000494:pharmacology; D016166:Free Radical Scavengers; D005978:Glutathione / Q000494:pharmacology; D008550:Melatonin / Q000494:pharmacology*; D010545:Peroxides / Q000494:pharmacology*; D010799:Phycoerythrin; D013997:Time Factors; D014810:Vitamin E / Q000494:pharmacology*
D000578:Amidines; D016166:Free Radical Scavengers; D010545:Peroxides; D010799:Phycoerythrin; D014810:Vitamin E; C049375:perhydroxyl radical; C046728:2,2'-azobis(2-amidinopropane); D005978:Glutathione; D008550:Melatonin; D001205:Ascorbic Acid