Induction of apoptosis by curcuminoids.

<p>(A) Phase contrast micrograph of NT2/D1 cells incubated with 47 µM media concentration of DMSO- solubilized curcuminoids for 18 h. Extensive cell death is indicated by rounding and detachment of cells. (B) At higher magnification, morphological changes consistent with apoptosis are observed. (C) Caspase activation by curcuminoids (46–49 µM) incubated for 0 (black bars), 6, 12, or 18 h either with SOLID- (gray bars) or DMSO-solubilized (white bars) curcuminoids. The activities reported for caspase 3 are to be considered a combination of the activities for caspases 3 and 7, since these share the same substrate and inhibitor specificity. (D) Detection of oligosomal DNA fragmentation by electrophoresis in 1% agarose and ethidium bromide staining. Lane 1: NT2/D1 cells after 6 h of incubation with 5 µM camptothecin, lane 2: Cells incubated without additives, lanes 3–5 cells incubated with 49 µM curcuminoids (DMSO-solubilized) for 6 h (lane 3), 12 h (lane 4), and 18 h (lane 5).