Fig. 1. Cell proliferation, ROS level, and GSH content in the A549 cells after they were treated with 1-AP and 3-AF. The A549 cells were treated with different concentrations of 1-AP and 3-AF (0, 5, 10, 20, 40 and 60 μM). (A): The cell proliferation was determined by MTT assay after 24 h treatment. (B): The level of intracellular ROS was assessed by the fluorescent probe DCFH-DA after 1 h exposure. (C): The GSH content was measured according to the manufacturer's instructions after 24 h treatment. The control groups were the A549 cells treated with DMSO (0.1%, v/v). *p < 0.05 and **p < 0.01 when compared with those of the control.