Figure 5. Effect of ethyl pyruvate on metabolic activity. Cell metabolic activity was assessed after 1 mM H₂O₂ treatment by 1-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Samples that received only pretreatment with ethyl pyruvate (EP) showed nearly no metabolic activity at all time points after initial stressing. Those that received pre- and cotreatment had significantly higher metabolic activity than control samples although this effect was not correlated to EP concentration. The asterisk indicates a statistically significant difference in the mean from the 0 mM EP samples at that time point (p<0.05). Means ± standard deviations for n=3 samples are plotted.