2.3. Cell culture and viability assay

Human neuroblastoma SK‐N‐MC cells were obtained from the American Type Culture Collection (Bethesda, MD, USA). Cells were maintained in minimal Eagle's medium (MEM, Gibco) supplemented with 10% fetal bovine serum, 100 units/mL penicillin, 100 μg/mL streptomycin, and 2 mmol/L L‐glutamine at 37°C and 5% CO₂. For the cell viability tests, cells were seeded in a 24‐well plate overnight and then treated with the indicated conditions. After 24 hours, MTT was added to the medium following the manufacturer's instructions. Only viable cells can metabolize MTT into a purple formazan product, and the color density of which was quantified by a Jasco V‐700 spectrophotometer (JASCO, Tokyo, Japan) at 550 nm. The average population number of control cells was set to 100% to enable comparison of the survival rates of other tested cells.