Cytotoxicity, antioxidant and glutathione S-transferase inhibitory activity of palladium(II) chloride complexes bearing nucleobase ligands

Abstract

Palladium(II) chloride complexes bearing the nucleobases, adenine, cytosine and guanine, have been synthesized and characterized by UV–vis spectrophotometric methods, magnetic susceptibility, molar conductivity, elemental analysis, FTIR and 1H-NMR. The complexes were found to have the general composition PdCl2(NH3L) (where L = adenine, cytosine or guanine). Square-planar geometry is proposed for these Pd(II) complexes based on magnetic evidence and electronic spectra. The complexes as well as the free nucleobase ligands show varying degrees of cytotoxicity on human promyelocytic leukemia (HL60) and human histiocytic leukemia (U937) cell lines, with cis-[PdCl2(NH3)(Gua)] showing IC50 values of 48.03 ± 9.67 and 11.12 ± 3.42 lM against HL60 and U937, respectively. The complexes as well as the ligands did not show anti-proliferative activity against a normal human cell line (NB1RGB). The complexes also show signifcant antioxidant activity against 2,2-diphenyl-1- picrylhydrazyl radical as well as glutathione S-transferase inhibitory activity