Re: Melatonin prevents delta-aminolevulinic acid-i

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1: Mol Cell Biochem 2001 Feb;218(1-2):87-92 <A

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Melatonin prevents delta-aminolevulinic acid-induced oxidative DNA damage in

the presence of Fe2+.

Qi W, Reiter RJ, Tan DX, Manchester LC, Calvo JR.

Department of Cellular and Structural Biology, The University of Texas Health

Science Center San , 78229-3900, USA.

Delta-aminolevulinic acid (ALA), a heme precursor which accumulates during

lead poisoning and acute intermittent porphyria, is reported to cause liver

cancer. The carcinogenic mechanisms of ALA may relate to its ability to

generate free radicals through metal-catalyzed oxidation which cause

oxidative DNA damage. The aim of this study was to compare the efficacy of

melatonin, trolox (vitamin E) and mannitol in altering DNA damage induced by

ALA. Herein, we found, in the presence of Fe2+, that ALA-induced formation of

8-hydroxydeoxyguanosine in calf thymus DNA was dose and time-dependent.

Melatonin, mannitol and trolox, all of which are free radical scavengers,

inhibited the formation of 8-hydroxydeoxyguanosine in a

concentration-dependent manner. The concentration of each (melatonin,

mannitol and trolox) required to reduce DNA damage by 50%, i.e., the IC50,

was 0.52, 0.84 and 0.90 mM, respectively.

PMID: 11330842 [PubMed - in process]