FIGURE 1.

A, time course of human UGT1A7 or UGT1A10 activity expressed in COS-1 cells following treatment with curcumin and calphostin-C. Cells, untreated or treated with 200 μm curcumin or 500 nm calphostin-C as shown, were harvested; cell extracts were assayed in vitro as described under “Experimental Procedures.” Experiments, carried out as described under “Experimental Procedures,” were repeated thrice in triplicates; standard errors ranged from ±2to ±5%. The MTT assay did not show toxicity after 8 h. B, in vitro glucuronidation of curcumin by UGT1A7 and UGT1A10 expressed in COS-1 cells using increasing concentrations. Experiments, carried out as described under “Experimental Procedures,” were repeated thrice in triplicates; standard errors ranged from ±2to ±3%.