MT-ND5 and melanoma: Against the A375 cell line, the tested compound exerted a strong cytotoxic activity (Figure 2); the viability of melanoma cells was most affected at the concentration of 1000 μg·mL−1, by Nd5 (32.67 ± 7.51%), followed by Nd4 (37.43 ± 7.85%), Nd3 (43.84 ± 5.88), Nd2 (51.28 ± 7.06%), Nd1 (63.65 ± 3.33%), and finally Nd0 (71.88 ± 1.57%) (Figure 7).