RETRACTED: Synthesis, structural characterization and anti-breast cancer activity evaluation of three new Schiff base metal (II) complexes and their nanoparticles

Two Schiff base ligands 2-((ethylamino)methyl)-6-methoxyphenol (HL1) and (E)-2-(((2-(dimethylamino)ethyl)imino)methyl)-6-methoxyphenol (HL2) with bi-nucleating or tri-nucleating mode have been successfully prepared via an one step organic condensation reaction, which were further applied in the synthesis of three new Cu(II) and Ni(II)-based coordination complexes [Cu(L1)2](EtOH) (1), [Ni(L1)2](EtOH) (2) and [Cu(L2)(HL2)(SCN)](MeOH)2 (3). Furthermore, a hand grinding technique has been used to decrease the particle diameter of complexes 1–3, thus forming nano-complexes. In biological activity research, we revealed the important function of nanoparticle 1 in the treatment of breast cancer. Mitochondria is critical in generating intracellular energy, and play a vital role in regulating cells life and death. Therefore, the apoptosis of MCF7 breast cancer cells after treated with nanoparticles was detected by Annexin V-FITC/PI method. The results showed that nanoparticles 1 could significantly raise apoptotic cells number, but not nanoparticles 2–3. Moreover, we assessed the mitochondrial membrane potential and reactive oxygen species (ROS) in MCF7 cancer cells, finally we draw this conclusion, nanoparticle 1 could damage the mitochondrial membrane, leading increased ROS level, and cause the apoptotic cell death.