Handbook of Vitamin C Research

Vitamin C Protects from Oxidative DNA Damage… 105Oxidative DNA Damage Induction by a Simultaneous Treatment of NPIP orNDBA and Vitamin C in Combination with OSCsThe effect of DADS/DPDS (0.1, 1 and 2.5 M) or DPS (1, 10 and 50 M) alone on NPIPor NDBA-induced oxidative DNA damage in HepG2 cells incubated with Fpg enzyme waspreviously evaluated in our laboratory [71]. The results obtained in these experiments showedthat the higher protective effect of DADS/DPDS alone towards oxidative DNA damageinduced by NPIP and NDBA was observed at 1 and 0.1 M, respectively, whereas it wasnecessary to use higher concentrations of DPS to observe similar protective effect (10 and 1M, respectively). Thus, in the present chapter it has been presented the protective effect ofOSCs alone or in combination with vitamin C (10 M) at these concentrations.The protective effect of DADS, DPS or DPDS alone on NPIP or NDBA-inducedoxidative DNA damage in HepG2 cells incubated with Fpg enzyme is shown in Figure 9 A.The results obtained showed that the formation of Fpg sensitive sites induced by NPIP wasslightly reduced by DADS (1 M, 14%), DPS (10 M; 24%) and DPDS (1 M, 55%).However, the formation of Fpg sensitive sites induced by NDBA was drastically preventedby lower concentrations of DADS (0.1 M, 92%), DPS (1 M, 66%) and DPDS (0.1 M,80%).Figure 9.Figure 9. Effect of DADS, DPS or DPDS (A) alone or (B) in combination with vitamin C towards NPIPand NDBA-oxidative DNA damage in human HepG2 cells. C 1 , ( ) HepG2 cells treated with NPIP 44mM or ( ) NDBA 3 mM and incubated with Fpg enzyme. ( ) HepG2 cells simultaneously treated withNPIP and DADS (1 M), DPS (1 M) or DPDS (10 M) alone or in combination with vitamin C (10M). ( ) HepG2 cells simultaneously treated with NDBA and DADS (0.1 M), DPS (1 M) or DPDS(0.1 M) alone or in combination with vitamin C (10 M). Asterisks indicate significant difference fromcontrol ***p 0.001, ** p 0.01 and *p 0.05.