Synthesis, Characterization and Anticancer Activity of Pyrazine-2-Carboxamide Metal Complexes

We explore the synthesis of metal complexes of a renowned antituberculosis drug, pyrazinamide (PZ) with copper, ferrous, ferric, cobalt and manganese. A detailed characterization of the resulting complexes was performed for establishing their structures by using spectroscopic techniques like NMR, FTIR, PXRD and SEM. These compounds were also explored for anticancer activity on SNB-19, HCT-15, COLO-205, and KB-3-1 cell lines and were found to be non-or low toxicity as most of the tested compounds' IC50 > 100 mu M. Scanning electron microscopy (SEM) revealed marked changes in the morphology after complexation. Compared to the pure PZ, an abrupt change in the morphological features of the complexes was likely caused by the chelating of PZ molecules with the metals. The micrographs of complexes depict a uniform matrix which indicates complete complex formation of with the drug uniformly dispersed at the molecular level. X-ray diffraction (PXRD) data suggested crystalline nature for the pure ligand and its corresponding complexes and this observation is well supported by morphological characterizations performed using Scanning Electron Microscopy.