Three novel Mannich bases 5-[(4-chlorophenyl)-(4-methylpiperazin-1-yl)-methyl]-pyrimidine-2,4,6-trione :CBzBAPz(NM), 5-[(4-nitrophenyl)-(4-methylpiperazin-1-yl)-methyl]-pyrimidine-2,4,6-trione: NBzBAPz(NM) and 5-[(phenyl)-(4-methylpiperazin-1-yl)-methyl]-pyrimidine-2,4,6-trione: BzBAPz(NM) are prepared by the condensation of N-methyl piperazine with p-chlorobenzaldehyde / p-nitro benzaldehyde / benzaldehyde and barbituric acid and  characterized by physico-chemical,  spectroscopic, and powder X-ray diffraction studies. Further, Cu (II), Cd (II) and Pd (II) complexes of titled ligands are synthesized and characterized. Based on the experimental results, the chelating (bidentate) behavior of the ligands is accessed. The X-band e.p.r.spectrum, electrochemical studies of the Cu (II) complex have been carried out and discussed. Three novel Mannich bases and their complexes exhibit comparable potential cytotoxicity against breast cancer cell line (MCF-7), particularly, strong cytotoxicity is observed in the case of palladium. Morphological features of cells used for the study is photographed. Use of fluorochromesacridine orange and ethidium bromide reveals apoptotic morphological features.