Determination of tumor necrosis factor-alpha (TNF-α) production by LPS-activated macrophages
RAW264.7 cells were seeded in the 96-well microplate at a density of 1.0×106 cells/100 µl/well and incubated for 1 h, and then the cells were treated with various concentrations of compounds for 10 min. After that, LPS (1 µg/ml) was added to each well and the cells were incubated for 20 h. The supernatant (50 µl) was transferred to ELISA plate and levels of TNF-α in the culture media were determined using a commercial kit (Mouse TNF-α ELISA kit, R&D System) according to the manufacturer׳s instructions and the absorbance was read at 450 nm within 30 min.