MTT™ cell viability test

To determine the effective cytotoxicity of screening drugs, MTT assay was used for cell viability and proliferation. In general, all incubated cancer cell lines (A549 and H460) were seeded in a 96-well microplate for up to 24 h dependent on the baseline growth rate. After incubation, candidate drugs were added into the plate and incubated together for 72 h. For performing the assay, 50 μl MTT solution (2 mg/ml) per well was added and incubated at 37 °C for 2 h. The 150 μl supernatant per well was then extracted and DMSO was filled to dissolve the recipe. The absorbance was set up at 570 nm and calculated by using ELISA reader (Infinite® M1000, TECAN, Switzerland). Ratio decrease comparing to the control group as 100 % viable was seemed as the inhibitory effect.