Figure 4.

Effect of propolis treatment on cellular survival after exposure to H₂O₂. Wild type and mutants strains were harvested in the mid exponential phase and stressed with 2 mM H₂O₂ / 1 h. Cells were directly stressed (white bars) or previously treated with propolis (25 μg/mL) during 60 min before being exposed to H₂O₂ stress (hatched bars). The results expressing percentage of survival in relation to non-stressed cells were obtained from the average ± standard deviation of three independent experiments. Different letters mean statistically different results.