Chromium(III)-induced 8-hydroxydeoxyguanosine in DNA and its reduction by antioxidants: Comparative effects of melatonin, ascorbate, and vitamin E

Wenbo Qi, Russel J. Reiter, Dun Xian Tan, Joaquin J. Garcia, Lucien C. Manchester, Malgorzata Karbownik, Juan R. Calvo

Research output: Contribution to journalArticlepeer-review

110 Scopus citations

Abstract

Chromium compounds are well documented carcinogens. Cr(III) is more reactive than Cr(VI) toward DNA under in vitro conditions. In the present study, we investigated the ability of Cr(III) to induce oxidative DNA damage by examining the formation of 8-hydroxydeoxyguanosine (8-OH-dG) in calf thymus DNA incubated with CrCl3 plus H2O2. We measured 8-OH-dG using HPLC with electrochemical detection. In the presence of H2O2, we observed that Cr(III)-induced formation of 8-OH-dG in isolated DNA was dose and time dependent. Melatonin, ascorbate, and vitamin E (Trolox), all of which are free radical scavengers, markedly inhibited the formation of 8-OH-dG in a concentration-dependent manner. The concentration that reduced DNA damage by 50% was 0.51, 30.4, and 36.2 μM for melatonin, ascorbate, and Trolox, respectively. The results show that melatonin is 60- and 70-fold more effective than ascorbate or vitamin E, respectively, in reducing oxidative DNA damage in this in vitro model. These findings also are consistent with the conclusion that the carcinogenic mechanism of Cr(III) is possibly due to Cr(III)-mediated Fenton-type reactions and that melatonin's highly protective effects against Cr(III) relate, at least in part, to its direct hydroxyl radical scavenging ability.

Original languageEnglish (US)
Pages (from-to)399-403
Number of pages5
JournalEnvironmental health perspectives
Volume108
Issue number5
DOIs
StatePublished - 2000

Keywords

  • 8-hydroxydeoxyguanosine
  • Ascorbate
  • Chromium
  • Melatonin
  • Vitamin E

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis

Fingerprint Dive into the research topics of 'Chromium(III)-induced 8-hydroxydeoxyguanosine in DNA and its reduction by antioxidants: Comparative effects of melatonin, ascorbate, and vitamin E'. Together they form a unique fingerprint.

Cite this