SHORT COMMUNICATION: Effect of ascorbate and 5-aminosalicylic acid on light-induced 8-hydroxydeoxyguanosine formation in V79 Chinese hamster cells

Recently we showed that ascorbate and 5-aminosalicylk acid (5-ASA) prevented 8-hydroxydeoxyguanosine (8-OHdG) formation in calf thymus DNA exposed to UV-visible light. However, the ultimate defense against oxidative DNA damage depends on an intracellular/intranuclear effect of the compounds. In the present study we investigated the effect of ascorbate and 5-ASA on 8-OHdG formation in V79 Chinese hamster cells exposed to light from a sun-lamp. Exposure for 1 min (4560 mJ/cm2) increased 8-OHdG formation in cellular DNA to 30–40 times background level. Preincubation of the cells with ascorbate or 5-ASA at concentrations of 0.1, 1 and 10 mM diminished the 8-OHdG formation to 0.67, 0.74 and 0.49 times controls (P< 0.05) for ascorbate respectively, and to 0.82, 0.66 and 0.33 times controls (P < 0.05), for 5-ASA. These findings demonstrate that both ascorbate and 5-ASA prevent oxidative DNA damage in cells by acting as intracellular/intranuclear antioxidants.