Novel transition metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) with Schiff base Ligands “(E)-2-((2- hydroxyquinolin-3-yl)methyleneamino)-1H-purin-6(7H)-one” abbreviated as GUOH and “(E)-2-((2- mercaptoquinolin-3-yl)methyleneamino)-1H-purin-6(7H)-one” abbreviated as GUSH derived by the condensation of 2-amino-1,9-dihydro-6H-purin-6-one (Guanine) with 3-formyl-2-hydroxy quinoline and with 3-formyl-2- mercapto quinoline respectively and characterized by elemental analysis, molar conductance, magnetic susceptibilities, UV, IR, 1H-NMR, ESR and thermal studies. The elemental and spectral analysis of the complexes confirms [M(GUOH)2(H2O)2] and [M(GUSH)2(H2O)2] stoichiometry and exhibits octahedral geometry, where M= Co(II), Ni(II), Cu(II) and Zn(II) respectively. Both the ligands act as monobasic and didentate, coordinating through azomethine nitrogen, quinoline oxygen via deprotonation. The synthesized ligands and the metal complexes were screened for the antibacterial, antifungal, DNA cleavage, DNA binding, Cytotoxic, Nephrotoxic, and Anticancer studies. The results reveal that the metal complexes possess higher antimicrobial activity than their corresponding ligands and Cu(II) complexes are found to be more active than the other complexes.[Ni(GUOH)2(H2O)2], [Co(GUSH)2(H2O)2] and [M(GUSH)2(H2O)2]have shown complete cleavage of CT-DNA where as other samples have displayed partial cleavage and DNA binding studies of selected compounds revels the Intercalative mode of bindings with CT-DNA.From the Anticancer analysis it is found that [Cu(GUSH)2.(H2O)2] is showing better activity against Cervical Canceramong other tested cell lines,the activity is in the order: Cervical Cancer(HeLa)> Breast Cancer(MCF-7)>Skeletal muscle Myoblast(L6)>Monkey kidney cancer cell lines(Vero)> HumanColon Cancer cell line(HT-29). Nephrotoxicity test against NRK 49F(KIDNEY) shows that the complex Cu(II) complex is showing Nephrotoxicity at CTC50( μg/ml) =526.67±06.
