(a) Intracellular ROS generation induced by 1 (4 μM)
in HT29 cells, as reflected by the fluorescence of DCF in the absence
and presence of light (λ = 400–700 nm, 23 mW cm–2, 28 J cm–2). (b) Comparison of the cytotoxic effect
of 1 against HT29, A549, and HEK-293 cells in the absence
and presence of light (λ = 400–700 nm, 23 mW cm–2, 28 J cm–2). Comparison of the cytotoxic effect
of 1, 3, and 11 against (c)
HT29 and (d) A549 cells. For the treatment with 1 and 3, light irradiation (λ = 400–700 nm, 23 mW cm–2, 28 J cm–2) was also applied. The
concentrations for 3 and 11 were multiplied
by 3 in the figures. (e) Variation of the combination index with the
IC value determined from the dose-dependent survival curves of 1, 3, and 11 against HT29 and A549
cells. (f) Comparison of the cytotoxic effect of 1, 3, and 11 against the chemo-resistant R-HepG2
cells in the absence and presence of light (λ = 400–700
nm, 23 mW cm–2, 28 J cm–2). For
(b)–(d) and (f), data are expressed as the mean ± standard
error of the mean (SEM) of three independent experiments, each performed
in quadruplicate.