IFNG and cancer: The curcuminoid-free interval after addition of NK cells resulted in the following mean IFN-γ levels: (a) co culture of NK and cancer cells without curcuminoids for 48 h: 201 pg/ml; (b) co culture without curcuminoids for 24 h: 90 pg/ml; (c) co culture with constant presence of curcuminoids for 48 h: 27 pg/ml (Figure 6A).