Fig. 6

Intracellular ROS generation in absence (–NAC) or presence (+NAC) of N-acetylcysteine. a Quantitative intracellular DCF fluorescence intensity of NCI-H358 cells induced by F3 fraction with or without the presence of NAC. The data are expressed as means ± SD from three independent experiments. Significances are shown in comparison to control and to the preincubated cells with NAC for each F3 fraction dose (*p < 0.05; **p < 0.01; ***p < 0.001; vs. control and ^# p < 0.05; ^## p < 0.01, vs. the corresponding dose of F3 fraction with NAC pre-treatment). b Microscopic images of ROS generation in NCI-H358 cells after treatment with different concentrations of F3 fraction (½ IC₅₀, IC₅₀ and 2 IC₅₀) for 4 h