Abstract
Ten coordination compounds, [Cu(L(1))Cl] (C1), [Cu(L(1))NO(3)] (C2), [Cu(L(2))Cl] (C3), [Cu(L(2))NO(3)] (C4), [Cu(L(3))Cl] (C5), [Cu(L(3))NO(3)] (C6), [Cu(L(4))NO(3)] (C7), [Cu(L(4))Cl] (C8), [Cu(L(5))Cl] (C9), and [Cu(L(5))NO(3)] (C10), containing pyridine derivatives of N(4)-methoxyphenyl-thiosemicarbazones were synthesized and characterized. The molecular structure of four compounds was investigated using single crystal X-ray diffraction. Spectral analysis techniques such as FT-IR, (1)H NMR, (13)C NMR, elemental analysis, and molar conductivity were used for all the synthesized compounds. The tested synthesized compounds were evaluated for their anticancer activity and selectivity against a variety of cancer cell lines, including HL-60, LNCaP, MCF-7, HepG-2, K-562, HeLa, BxPC-3, RD, and MDCK normal cell line. Most compounds demonstrated selective anticancer activity superior to doxorubicin. Notably, all ligands showed high antiproliferative activity against HL-60 cells, with IC(50) values between 0.01 and 0.06 µM and a selectivity index as high as 5000. Coordination of copper(II) with ligands HL(1) and HL(3) notably enhanced antiproliferative activity, lowering the IC(50) to 0.03 µM. Additionally, the antioxidant activity of these compounds was assessed, revealing that all tested ligands and most coordination compounds exhibited greater antioxidant activity compared to Trolox, with some ligands showing activity up to 12.3 times higher. Toxicity studies on Daphnia magna indicated low toxicity for the ligands, generally less than doxorubicin, with LC(50) values ranging from 13 to 90 µM, suggesting moderate toxicity. Conversely, the coordination complexes were more toxic, with LC(50) values between 0.5 and 13 µM.