Polarographic properties and potential carcinogenicity of some natural nucleosides and their synthetic analogues

The polarographic reduction and the index of potential carcinogenicity tg α determined polarographically in aprotic conditions and in the presence of α-lipoic acid of nine naturally occurring and synthetic pyrimidine and six synthetic 1,3,5-triazine (5-aza) nucleosides was compared to the reduction of eight synthetic 1,3,6-triazine (6-aza) nucleosides. Nucleosides are of interest because of their key role in the nucleic acid structure and because of the antimetabolite and cytotoxic/antileukemia properties of their synthetic analogues. It was shown that polarographic reduction of the studied compounds is achieved at gradually increased potentials in the order of 6-aza<5-aza<pyrimidine nucleosides. On other hand, the potential carcinogenicity of studied compounds increases usually in the order of pyrimidine<6-aza≪5-aza nucleoside. The only compounds with remarkable potential carcinogenicity identified at this study were those ones from the 5-aza (1,3,5-triazine) antimetabolite series - arabinosyl-5-azacytosine (0.275), 5-aza-cytidine (0.295) and 5-aza-uracil (0.400) - and 2,2′-anhydrouridine (0.260). The relation of the data obtained to biological activity of nucleosides included in the study is discussed.