Curcumin reduces SOD enzyme activity in wild-type cells but not in <i>pkaC</i> null cells.

<p>A) SOD enzyme activity in curcumin treated parental AX4 cells (5 μg/ml and 10 μg/ml) is reduced by nearly half relative to untreated cells. In contrast, there is much less effect on SOD enzyme activity in <i>pkaC</i> null cells treated with curcumin for 24 hours. B) Curcumin has no effect on the rate of generation of superoxide in the assay. 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>.