Effect of Curcumin and curcumin-PLGA conjugate on ROS generation and JNK activation.

<p>HCT 116 cells were treated with 10 μM and 20 μM of curcumin (C) and curcumin-PLGA conjugate (CP) for 3 h, 6 h, 9 h and 12 h. Similarly, 0.4 μl DMSO was used as a vehicle control. Thereafter, the cells were washed and incubated with H₂DCFDA dye for 20 min. The liberation dichlorofluorescein (DCF) fluorescence was recorded under multi-mode plate reader. Graphs represent the fluorescence unit of dichlorofluorescein (DCF). (A) Graph represents a level of ROS in the absence of N-acetyl cysteine (NAC). (B) Percent inhibition of cell proliferation determined by MTT assay in the absence of NAC. (C) Graph represents a level of ROS in the presence of N-acetyl cysteine (NAC). (D) Percent inhibition of cell proliferation determined by MTT assay in the presence of NAC. Error bars represent mean ±SEM from three independent experiments. Significant difference indicated as *p≤0.05 between untreated and curcumin treated cells; ^#p≤0.05 between untreated and curcumin-PLGA conjugate treated cells; ^§p≤0.05 between curcumin and curcumin-PLGA conjugate treated cells (One way ANOVA followed by Student Newman-Keuls multiple comparisons test). (E) Western blots of phosphorylated JNK and JNK in presence and absence of NAC. Cells were pretreated with NAC for 3 h and thereafter treated with 10 μM and 20 μM of curcumin (C) and curcumin-PLGA conjugate (CP) for 12 h and 24 h.