TY - JOUR
T1 - DNA oxidatively damaged by chromium(III) and H2O2 is protected by the antioxidants melatonin, N1-acetyl-N2-formyl-5-methoxykynuramine, resveratrol and uric acid
AU - Burkhardt, Susanne
AU - Reiter, Russel J.
AU - Tan, Dun Xian
AU - Hardeland, Rüdiger
AU - Cabrera, Javier
AU - Karbownik, Malgorzata
N1 - Funding Information:
Susanne Burkhardt has been supported by a fellowship of the Deutsche Forschungsgemeinschaft. Malgorzata Karbownik was supported by an American Cancer Society International Fellowship for Beginning Investigators.
PY - 2001
Y1 - 2001
N2 - Chromium (Cr) compounds are widely used industrial chemicals and well known carcinogens. Cr(III) was earlier found to induce oxidative damage as documented by examining the levels of 8-hydroxydeoxyguanosine (8-OH-dG), an index for DNA damage, in isolated calf thymus DNA incubated with CrCl3 and H2O2. In the present in vitro study, we compared the ability of the free radical scavengers melatonin, N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK), resveratrol and uric acid to reduce DNA damage induced by Cr(III). Each of these scavengers markedly reduced the DNA damage in a concentration-dependent manner. The concentrations that reduced 8-OH-dG formation by 50% (IC50) were 0.10 μM for both resveratrol and melatonin, and 0.27 μM for AFMK. However, the efficacy of the fourth endogenous antioxidant, i.e. uric acid, in terms of its inhibition of DNA damage in the same in vitro system was about 60-150 times less effective than the other scavengers; the IC50 for uric acid was 15.24 μM. These findings suggest that three of the four antioxidants tested in these studies may have utility in protecting against the environmental pollutant Cr and that the protective effects of these free radical scavengers against Cr(III)-induced carcinogenesis may relate to their direct hydroxyl radical scavenging ability. In the present study, the formation of 8-OH-dG was likely due to a Cr(III)-mediated Fenton-type reaction that generates hydroxyl radicals, which in turn damage DNA. Once formed, 8-OH-dG can mutate eventually leading to cancer; thus the implication is that these antioxidants may reduce the incidence of Cr-related cancers.
AB - Chromium (Cr) compounds are widely used industrial chemicals and well known carcinogens. Cr(III) was earlier found to induce oxidative damage as documented by examining the levels of 8-hydroxydeoxyguanosine (8-OH-dG), an index for DNA damage, in isolated calf thymus DNA incubated with CrCl3 and H2O2. In the present in vitro study, we compared the ability of the free radical scavengers melatonin, N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK), resveratrol and uric acid to reduce DNA damage induced by Cr(III). Each of these scavengers markedly reduced the DNA damage in a concentration-dependent manner. The concentrations that reduced 8-OH-dG formation by 50% (IC50) were 0.10 μM for both resveratrol and melatonin, and 0.27 μM for AFMK. However, the efficacy of the fourth endogenous antioxidant, i.e. uric acid, in terms of its inhibition of DNA damage in the same in vitro system was about 60-150 times less effective than the other scavengers; the IC50 for uric acid was 15.24 μM. These findings suggest that three of the four antioxidants tested in these studies may have utility in protecting against the environmental pollutant Cr and that the protective effects of these free radical scavengers against Cr(III)-induced carcinogenesis may relate to their direct hydroxyl radical scavenging ability. In the present study, the formation of 8-OH-dG was likely due to a Cr(III)-mediated Fenton-type reaction that generates hydroxyl radicals, which in turn damage DNA. Once formed, 8-OH-dG can mutate eventually leading to cancer; thus the implication is that these antioxidants may reduce the incidence of Cr-related cancers.
KW - 8-Hydroxydeoxyguanosine
KW - Cancer
KW - Chromium
KW - Free radical scavenger
KW - Melatonin
UR - http://www.scopus.com/inward/record.url?scp=0034993134&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034993134&partnerID=8YFLogxK
U2 - 10.1016/S1357-2725(01)00052-8
DO - 10.1016/S1357-2725(01)00052-8
M3 - Article
C2 - 11404181
AN - SCOPUS:0034993134
SN - 1357-2725
VL - 33
SP - 775
EP - 783
JO - International Journal of Biochemistry and Cell Biology
JF - International Journal of Biochemistry and Cell Biology
IS - 8
ER -