Figure 4: (a) Curcumin induced degeneration of human colorectal cancer Caco-2 cells. Human colorectal cancer Caco-2 cells were cultured and seeded in 96-well plates at a density of 2 × 104 as described in the methods. At 72 h after treatment with varying concentrations of curcumin, cell viability was measured by fluorescence using the resazurin reduction assay. Each data point represents the mean ± SEM of 4 wells. The data are representative of 3 separate experiments (EC50 = 22.0 μg/mL). (b) PMPMEase activity in degenerating curcumin-treated human colorectal cancer Caco-2 cells. Cells were cultured to 80% confluence, lysed, and incubated with the indicated concentrations of curcumin as described in the methods. The residual PMPMEase activity was then determined using RD-PNB as the substrate. Each point represents the mean ± SEM . The data are representative of 3 separate experiments (IC50 = 22.6 μg/mL).