Antioxidant Mechanisms of Glutathione against Metal-Mediated Oxidative DNA Damage

Oxidative damage of DNA strands has been strongly linked with the development of diseases such as certain cancers, cystic fibrosis and Parkinson’s, as well as aging. In intercellular reactions involving hydrogen peroxide endogenous metals have been shown to increase the generation of site-specific base modifications through their formation of reactive oxygen species (ROS). The damage markers measured via HPLC are the 8-hydroxy-2’-deoxyguanosine (8-OHdG) and the dA-N1 oxide markers. The current study deals with the reduced form of the sulfur antioxidant glutathione (GSH) and elucidating its ameliorating effects against ROS formation. Comparative studies with the known radical-scavenging sulfur antioxidant dimethyl sulfoxide (DMSO) have also been performed. The fluorescent probe 2’,7’-dichlorofluorescein (DCF) was used to quantify the ROS production both in the presence and absence of both GSH and DMSO. Metal binding studies were conducted using isothermal titration calorimetry (ITC) in order to better interrogate the nature of the metal ion interactions with GSH. A better understanding of antioxidant mechanisms against oxidative DNA damage will eventually lead to the development of better therapeutics and treatment options against the aforementioned ailments and conditions in the future