Figure 4.

(A) C2C12 myotubes stained with mitochondrial potential indicator JC-1 after 20 h of incubation with H-TPP-DC (11) (125 nM) (top left); H-TPP-DC (11) (2 μM) (bottom left); 4-OMe-TPP-DC (9) (125 nM) (top middle); 4-OMe-TPP-DC (9) (2 μM) (bottom middle); 4-CF₃-TPP-DC (14) (125 nM) (top right); and 4-CF₃-TPP-DC (14) (2 μM) (bottom right). (B) Dose-dependent effects of modified TPP⁺-decyl compounds with electron-donating substitution on the phenyl rings (9, 10, and 30) and electron-withdrawing substitution on the phenyl rings (12, 13, and 14) or decyl Tris(1-Naphthyl)-P-DC (33) on mitochondrial membrane potential in intact C2C12 cells estimated as the ratio of red to green fluorescence of potential sensitive probe JC-1 normalized to the untreated control. Values represent mean ± SE, n = 3, * = p < 0.001 as compared to the untreated control as analyzed by two-way ANOVA and the post-hoc Tukey test using GraphPad prism. (C) Dose-dependent cell viability determined by the MTT assay in C2C12 cells incubated for 20 h with modified TPP⁺-decyl compounds with electron-donating substitution on the phenyl rings (9, 10, and 30) and electron-withdrawing substitution on the phenyl ring (12–14) or Tris(1-Naphthyl)-P-DC (33). Values represent mean ± SE, n = 3, * = p < 0.001 as compared to the untreated control as analyzed by two-way ANOVA and the post-hoc Dunnett test using GraphPad prism.