2.4. MTT assay

Cells were placed in a 96‐well plate and were incubated for 24 h. Then they were treated with various doses of Embelin (2.5–300 μM) for 24 h. After cells were treated with 500 μg/mL of thiazolyl blue tetrazolium bromide (MTT solution), they were incubated at 37°C with 5% CO₂ for 4 h. The medium was aspirated and formed formazan crystals were dissolved in DMSO. Cell viability was measured by an ELISA reader (Tecan, Männedorf, Switzerland) at 570 nm excitatory emission wavelength.