(a) Cell Viability (%) Mean Control 100 PhIP 50 mM 80 PhIP 50 mM+Cur 25 mM 78 PhIP 50 mM+Cur 50 mM 81 PhIP 50 mM+Cur 75mM 92* PhIP 50 mM+Cur 100 mM 97*** PhIP 50 mM+Cur 150 mM 101*** PhIP 50 mM+Cur 200 mM 81 PhIP 250 mM 33 PhIP 250 mM+Cur 25 mM 49* PhIP 250 mM+Cur 50 mM 69*** PhIP 250 mM+Cur 75mM 74*** PhIP 250 mM+Cur 100 mM 86*** PhIP 250 mM+Cur 150 mM 97*** PhIP 250 mM+Cur 200 mM 66*** (b) ROS Activation (Mean Relative Fluorescence Units) Control 3.33 PhIP 50 mM 6.33*** PhIP 250 mM 8.33*** PhIP 50 mM+Cur 150 mM 3.33*** PhIP 250 mM+Cur 150 mM 2.66*** Cur 150 mM 2 H2O2 1 mM 5 H2O2 10 mM 10.6 (c) Comet Assay (Mean Olive Tail Moment) Control 0.155 PhIP 50μM 1.02*** PhIP 250μM 1.5*** PhIP 50μM+Cu 150μM 0.26*** PhIP250 μM+Cu 150μM 0.53*** Cu 150μM 0.17 (a) Cell viability with various doses of curcumin co-treated with 50 mM and 250 mM PhIP. All doses of curcumin produced reversal of PhIP-induced cytotoxicity but curcumin at 150 μM exhibited the greatest degree of reversal of cytotoxicity. Line shows significance compared to PhIP treated samples. (b) Quantitative fluorescence intensity analysis of ROS production in PhIP-treated MCF-10A cells upon co-treatment with curcumin. MCF-10A cells were treated with or without PhIP in the presence and absence of curcumin for 24 hours and then fluorescence intensity was measured with DCF-DA (5 μg) within 45 minutes. Co-treatment with curcumin reduced the PhIP-stimulated ROS production in MCF-10A cells. (c) Inhibition of PhIP-induced DNA strand breaks by curcumin at 24h. MCF 10A cells were treated and analyzed to score comet tail moment using comet analysis system (Loats Associate System, Westminster, MD). Values are mean from three independent experiments performed in triplicate.  The statistical significance is expressed as *p<0.05, **p<0.01, and ***p<0.001.

Table 1: Effect of curcumin on inhibition of PhIP induced carcinogenicity.