Figure 1: Effect of different concentrations of FeSO4 (50-500 μM) (A), CuSO4 (50-300 μM) (B), and SYR (50-1 000 μM) (C) on HEK 293 and HepG2 cell viability after 24 h (upper) and 72 h (lower) of incubation. Cell viability was determined using MTT assay. The data are expressed as mean ± SD of at least three independent experiments and analyzed by one-way analysis of variance followed by Dunnett post-test. *P < 0.05; **P < 0.01; ***P < 0.001 compared with the control group. SYR: Syringic acid.