| Abstrakt: |
Interactions of Cu2+, Zn2+, and Pd2+ ions with the antitumor compound mitomycin C (MMC) have been investigated by UV−vis, circular dichroism, and 13C NMR spectroscopy. While Zn2+ and Cu2+ neither interacted with MMC nor catalyzed the formation of mitosenes, Pd2+ induced strong MMC spectral modifications, suggesting the formation of a major complex, in which MMC acted as a bidentate ligand through N(1) and N(4) atoms. The coordination mode in this complex was solvent dependent: in MeOH, the NH2 of the carbamate function was also involved as a third coordination site whereas, in H2O, Pd2+ hydrolysis was more effective, leading to the replacement of the carbamoyl NH2 function with either H2O or OH- ligands. Although coordination of the indoline nitrogen prevented methanol elimination and consequent aziridino ring opening, Pd2+ complexation maintained MMC biological activity against cancer cells, as shown by IC50 values. This suggests that alternative mechanisms in the biological activity of MMC should be explored. |
