Metal complexes of 'Heena' (2-hydroxy-1,4-naphthoquinone): Synthesis, Characterization and anticancer activity

The Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of Henna; 2-hydroxy-1,4-naphthoquinone (Lw) are synthesized at 0 degrees C (Mn2+; 1, Co2+; 2, Ni2+; 3, Cu2+; 4 and Zn2+; 5), 26 degrees C (Mn2+; 1A, Co2+; 2A, Ni2+; 3A, Cu2+; 4A and Zn2+; 5A) and characterized. The compositions of all complexes are of the type [M(Lw)(2)(H2O)(2)]. The geometry of the complexes synthesized at 26 degrees C is trans, whereas cis for complex 4 at 0 degrees C. The pyridine adduct (4Apy) of copper complexes 4A and methanol (4MeOH) adduct of complex 4 is characterized by single crystal X-ray diffraction studies. The molecular interactions are revealed from the X-ray structures of 2A, 5A, 4Apy, and 4MeOH. Anticancer activity of all complexes was evaluated against two cancer cell lines, MCF-7 (breast cancer cell line) and A-549 (lung cancer cell line). The complexes synthesized at 0 degrees C show enhanced activity against the A549 cell line. Cell cycle analysis, effect on mitochondrial potential, estimation of Reactive Oxygen Species (ROS), effect on peripheral blood mononuclear cells (PBMCs), Tunnel assay, etc., experiments were performed on complex 1A.