Fig. 1. Protective effect of I6CA on H₂O₂-induced cytotoxicity in V79-4 cells. The cells were treated with various concentrations of I6CA (A) or H₂O₂ (B) for 24 h or pretreated with or without 300 μM I6CA or 10 mM NAC for 1 h and then cultured in the presence of 1 mM H₂O₂ for 24 h (C and D). (A-C) The cell viability was determined by an MTT assay. The results are expressed as the mean ± SD obtained from three independent experiments (**p<0.01 and ***p<0.001 compared with the control group; ###p<0.001 compared with the H₂O₂-treated group). (D) Representative images of the cells were captured by a phase-contrast microscope (original magnification, 200×).