Details

Autor(en) / Beteiligte

• Fischer-Nielsen, Anne
• Poulsen, Henrik E.
• Loft, Steffen

Titel

8-Hydroxydeoxyguanosine in vitro: Effects of glutathione, ascorbate, and 5-aminosalicylic acid

Ist Teil von

• Free radical biology & medicine, 1992, Vol.13 (2), p.121-126

Ort / Verlag

New York, NY: Elsevier Inc

Erscheinungsjahr

1992

Quelle

Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)

Beschreibungen/Notizen

• Oxidative DNA damage, as expressed by 8-hydrogydeoxyguanosine (8-OHdG), was investigated in calf thymus DNA exposed to either ultraviolet radiation or to FeCl 2/H 2O 2 in a Fenton-like reaction. The influence of iron (absent in the UV system and present in the FeCl 2/H 2O 2 system) and pH (7.4 and 4.0) on the effect of glutathione (GSH), ascorbate, and 5-aminosalicylic acid (5-ASA, a drug used in the treatment of chronic inflammatory bowel diseases) was examined in these systems. Without iron, all three compounds considerably reduced 8-OHdG formation (i.e., acted as scavengers), while in the presence of iron salts, 8-OHdG formation was accelerated (except for GSH at pH 7.4), i.e., the compounds acted as prooxidants. This effect was augmented at low pH. The prooxidant property of 5-ASA may have implications for its clinical use. Maximum scavenging effect for all the compounds investigated was obtained at much lower doses than the maximum enhancing effect. This demonstrates that to the end of oxy-radical scavenging, the concentration of the GSH, ascorbate, and 5-ASA, respectively, should be chosen to obtain maximum antioxidant effect and minimum prooxidant effects. The significance of this finding for the selection of antioxidant dose is important but remains to be investigated further.