Effect of turmeric on tumor cell proliferation. (A) U266, KBM-5, Panc-28, HCT-116, MDA-MB-231, and HT-29 cells (5×103 cells/well) were seeded in triplicate in 96-well plates, treated with turmeric (25 μg/mL) for 0, 2, 4, and 6 days. (B) U266, KBM-5, Panc-28, HCT-116, MDA-MB-231, and HT-29 cells (5×103cells/well) were seeded in triplicate in 96-well plates, treated with turmeric (0, 2.5, 5, 12, and 25 μg/mL) for 72 h, and then assayed for cell viability by the MTT method. (C) Effect of turmeric and curcumin on tumor cell cytotoxicity. U266, KBM-5, Panc-28, HCT-116, MDA-MB-231, CaCo-2, and HT-29 cells (5×103 cells/well) were treated with turmeric (70 μg/mL) and curcumin (5 μg/mL) for 72 h and then cell viability was measured by the MTT method. Data represent the mean±SD of three measurements. *p<0.05; **p<0.01 with respect to control.