2.4. DNA biosynthesis

Cells were plated in 24‐well plates at 4 × 10⁴ cells per well and allowed to adhere for 24 h. Cells were treated with the various concentrations of flavonoids (25, 50 and 100 μM) in 1 mL medium containing 0.5 μCi [³H]‐thymidine (#MT6037, Hartmann Analytic, Germany) for 48 h. Medium was discarded, and cells were rinsed three times with phosphate buffered saline (PBS), and solubilized with 1 mL of 0.1 M sodium hydroxide containing 1% sodium dodecyl sulphate. Then, 9 mL of scintillation liquid (PerkinElmer, USA) was added, and radioactivity incorporated into DNA was measured using a scintillation counter.