The interaction of native
calf thymus DNA with
tartrazine in 10 mM Tris-HCl aqueous
solution at neutral pH 7.4 was investigated.
Tartrazine is a nitrous derivative and may cause
allergic reactions, with a potential of toxicological risk. Also,
tartrazine induces oxidative stress and DNA damage. Its
DNA binding properties were studied by UV-vis and circular dichroism spectra, competitive binding with
Hoechst 33258, and viscosity measurements.
Tartrazine molecules bind to
DNA via groove mode as illustrated by hyperchromism in the UV absorption band of
tartrazine, decrease in Hoechst-
DNA solution fluorescence, unchanged viscosity of
DNA, and conformational changes such as conversion from B-like to C-like in the circular dichroism spectra of
DNA. The binding constants (K(b)) of
DNA with
tartrazine were calculated at different temperatures. Enthalpy and entropy changes were calculated to be +37 and +213 kJ mol(-1), respectively, according to the Van't Hoff equation, which indicated that the reaction is predominantly entropically driven. Also,
tartrazine does not cleave plasmid
DNA.
Tartrazine interacts with
calf thymus DNA via a groove interaction mode with an intrinsic binding constant of 3.75 × 10(4) M(-1).