Figure 5.

Dose–response curves of compound 3 in the absence and presence of ultraviolet irradiation. Cells were incubated for 1 h with the compounds and were then irradiated at 365 nm (4.1 mW/cm²). Cell growth was determined 10 days after incubation with the compounds. Irradiated compounds showed left-shifted dose–response curve compared to that of the unirradiated compounds. Error bars represent the standard deviation from duplicate determinations, and results are shown as mean ± SD. The IC₅₀ value is presented in Table 3.