Figure 6.

(A) ROS elevation in A549 cells treated with 4a or 4b. Cells were treated with 4a or 4b at the indicated concentrations for 6 h, and stained by H₂DCFDA. Samples were detected by flow cytometry and confocal microscopy. The excitation wavelength of DCF was 488 nm. Emission was collected at 510‒540 nm. Scale bar: 20 μm. (B) The impact of scavenging ROS by NAC on anti-proliferative activity of 4a or 4b. Cells were pre-incubated with NAC for 1 h, and then treated with 4a or 4b for 24 h. Cell viability was measured by MTT assay. **p < 0.02.