Synthesis and DNA binding studies of Mg(II) complex of Schiff base derived from vanillin and L-tryptophan.

The Mg(II) complex of Schiff base (K[HL]) derived from vanillin and L-tryptophan could bind with herring sperm DNA. The binding behaviors between them in physiological pH environment (pH 7.40) have been studied by spectroscopy, cyclic voltammetry and viscosity methods. Binding ratios of n(Mg(II)): n(K[HL]) = 1:1 and n(Mg(II)L): n(DNA) = 5:1 were confirmed. The obtained thermodynamic parameters suggest that the interaction between Mg(II)L and DNA is driven mainly by entropy. Combined with fluorimeteric studies, cyclic voltammetry, CD spectroscopy and viscosity methods, the results indicate the interaction modes between Mg(II)L and DNA are mainly with intercalation and involving some electrostatic interaction.