SYNTHESIS AND EVALUATION OF ANTIOXIDANT ACTIVITY OF SOME HYDRAZONES WITH XANTHINE STRUCTURE

Aim: To synthesize some hydrazones with xanthine structure and to evaluate their antioxidant activity. Material and methods: The synthesis started from theophylline sodium salt, prepared from theophylline and sodium methoxide, which was transformed into its ethyl ester and then in hydrazide. The hydrazone derivatives were obtained by the condensation of hydrazide with different aromatic aldehydes (benz­aldehyde, 4-nitro/3-nitro/3-hydroxy/4-chloro/4-bromo-benzaldehyde). The antioxidant poten­tial was evaluated in vitro by using the DPPH radical scavenging assay and was compared with theophylline activity used as parent compound. Results: Six hydrazones with xanthine structure were obtained. They were characterized in terms of their physical properties and their structures were confirmed by IR and 1H-NMR spectroscopy. Some of these compounds have an antioxidant effect more pronounced than theophylline at higher concentrations. The most active compound was 3-nitro-benzylidene-hydrazino-acetyl-theophylline (compound g), with an inhibition rate of  65% ± 0.99 at 30 min and 79% ± 0.81 at 60 min. Conclusions: The antioxidant activity of synthesized hydrazones depends on the substituents used in structural modulation. The substitution of aromatic ring with nitro group in meta position had the most favorable influence.