Methods and Results: MTT method was used to measure cell viability. 
MTT method
Flow cytometry was used for detecting the apoptosis rate. 
Flow cytometry
Reactive oxygen species (ROS) activity was determined using fluorescence microscope. 
fluorescence microscope
The expression of mRNA in apoptosis-related genes (Caspase 3, Caspase 8, and Caspase 9) were tested by qPCR. 
qPCR
The effects of POL, ACT, FTB on the activities of nuclear factor erythroid-2 related factor 2 (Nrf2), nuclear factor kappa-B (NF-κB) and the expression of their downstream genes were assessed by western blotting and RT-PCR in A549 cells. 
western blotting
The effects of POL, ACT, FTB on the activities of nuclear factor erythroid-2 related factor 2 (Nrf2), nuclear factor kappa-B (NF-κB) and the expression of their downstream genes were assessed by western blotting and RT-PCR in A549 cells. 
RT-PCR