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-aminosalicytic acid (5-ASA) pr evented 8-hydroxydeoxyguanosine (8-OHdG) formation in calf thymus DNA exposed to UV - visible light. However, the ultimate defense against o xidative DNA damage depends on an intracellular/intranuclear effect of the compounds. In the present study we investigated the effect of asc orbate and 5-ASA on 8-OHdG formation in V79 Chinese hamster cells expo sed to fight from a sun-lamp. Exposure for 1 min (4560 mJ/cm2) increas ed 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 0.8 2, 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.