A spectroscopic and pulse radiolysis study of allopurinol and its copper complex

vibrational spectroscopy and pulse radiolysis technique in order to obtain some elucidation on the mechanism of its beneficial effect against oxygen free radical-mediated damage. ALP is suggested to give protection to living organisms both by metal chelation and direct scavenging of free radicals. The Raman and IR spectra have been useful to assess the relevant interactions of ALP with Cu(II) ions, which play an important role in the metal catalysed generation of reactive oxygen species. A proposal of the complex structure was performed; the predominant species seems to be a monomeric complex where ALP interacts with the metal by one nitrogen atom of the five-membered ring and the CyO group. The pulse radiolysis data have given information on the behaviour of ALP towards radiation-induced radicals. ALP appears to be a good scavenger of zOH, giving rise to intermediate transients, namely resonance-stabilised phenoxyl radicals. Also in the presence of Cu(II) ions, ALP reacts fast towards zOH radicals.