Effect of gamma irradiation on the Cu(II), Ru(III) and Pd(II) complexes of azo antipyrine moiety and their biological applications

Three novel Cu(II), Ru(III), and Pd(II) chelates of the ligand N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)carbonohydrazonoyl dicyanide (HL) were synthesized and fully characterized using IR, NMR, elemental analysis, molar conductivity, melting point, mass spectra, electronic spectra, PXRD, and thermal analysis. Geometry optimization with Gaussian09 confirmed the structures: [Cu(HL)Cl(OH)].H₂O (B1), [Ru(HL)Cl₂(OH)(H₂O)].H₂O (B2), and [Pd(HL)Cl₂].2H₂O (B3). The antibacterial and anticancer activities of non-irradiated and γ-irradiated complexes were evaluated against multiple bacterial strains and the MCF-7 breast cancer cell line. The results demonstrated that most of the tested compounds possess broad-spectrum bactericidal activity. The Cu(II) complex (B1) exhibited the highest anticancer activity, followed by Ru(III) (B2), Pd(II) (B3), and the free ligand HL. Moreover, after irradiation, both the ligand and its complexes became more active against tumor cells. Molecular docking studies supported these results, revealing strong interactions with target proteins responsible for microbial and cancer inhibition. This study highlights the novelty of the metal-HL complexes and shows how γ-irradiation can influence their biological behavior. After irradiation, the complexes displayed stronger activity against cancer cells but a reduced effect on bacteria and fungi, pointing to their potential use as selective multifunctional therapeutic agents.