Aluminium(III), chromium(III) and iron(III) complexes with 5-iodouracil and 5-iodouracil-histidine and their antitumour activity

Abstract

Complexes of the type [Al(HL)(OH)Cl2], [M(HL)(OH)2 Cl] and [M′(HL)(L′)(OH)Cl], where HL = 5-iodouracil; HL′ = histidine; M = Cr(III), Fe(III) and M′ = Al(III), Cr(III), Fe(III), were synthesized and characterized. The complexes are polymeric showing high decomposition points and are insoluble in water and common organic solvents. The μeff values, electronic spectral bands and ESR spectra suggest a polymeric 6-coordinate spin-free octahedral stereochemistry for the Cr(III) and Fe(III) complexes. 5-Iodouracil acts as a monodentate ligand coordinating to the metal ion through the O atom of C(4) = O while histidine through the O atom of -COO- and the N atom of -NH2 group. In vivo antitumour effect of 5-iodouracil and its complexes was examined on C3H/He mice against P815 murine mastocytoma. As evident from their T/C values, Cr(III) and Fe(III) complexes display significant and higher antitumour activity compared to the 5-iodouracil ligand. The in vitro results of the complexes on the same cells indicate that Cr(III) and Fe(III) complexes show higher inhibition on 3 H-thymidine and 3H-uridine incorporation in DNA and RNA replication, respectively, at a dose of 5 μg/mL.