Cell proliferation assay.

Vitality of HepG2 cells treated with apigenin and luteolin 1 µM–100 µM for 24 h.HepG2 survival was measured using the CellTiter96 Aqueous ONE Solution from Promega applied to cell-cultures after 24 h treatment with flavones apigenin and luteolin in the range from 1–100 µM. Following incubation with 20 µM (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy phenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt (MTS)/phenazine methosulfate (PMS - electron coupling reagent) for 4 h at 37°C, the optical density of the MTS bioreduction product formazan was measured at 490 nm. Means of OD-values were normalized to mock treated cells (100% survival) and analyzed by Oneway ANOVA for 0, 1, 2, 5, 10, 20, 50, and 100 µM apigenin and luteolin respectively with Levene statistics for analyses of variance. Significant reductions of vitality were found for 100 µM apigenin or luteolin vs 0 µM in mock treated control cells with DMSO 0.5% analyzed by Dunnett T3 (unequal variance for apigenin) or Bonferroni (equal variance for luteolin) respectively.