The antioxidant NAC affects cells differently than curcumin and does not reverse the oxidant effect of curcumin.

<p>The antioxidant NAC, known to counter the effect of oxidative stress, does not have any effect on cell proliferation of wild-type <i>D</i>. <i>discoideum</i> cells: A) Cell Titer Glo assay and B) direct cell counting. C) NAC did not counter the effect of curcumin on cells treated for 24 hours, indicating that the effect of curcumin on catalase A specific enzyme activity was not directly due to oxidative stress. D) Increased NAC concentrations inhibit cell proliferation at very high concentrations. E) However, these increasing concentrations of NAC still do not counter the effect of cells treated with curcumin for 24 hours. P-values are defined in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0187562#pone.0187562.g002" target="_blank">Fig 2</a>.</p>