Figure 6 Without functional p53, silibinin treatment induced the generation of NO and elevated the level of GSH. A431 cells were cultured in Ham's F-12 medium with 10% FBS and subsequently cultured in SFM media for 24 h. The cells were incubated with different concentrations of silibinin (100, 200, 300 or 400 µM) for 12 h. A: The level of GSH was determined by a GSH assay kit. B: The level of NO was determined by DA F-2DA staining and measured by flow cytometry.