A spectral study of the interaction between chelerythrine chloride and cytidine

To study the possible anticancer mechanisms of chelerythrine (CHE), and its interactions with cytidine were investigated by UV–vis spectrophotometric and spectrofluorimetric measurements and by thermodynamic calculations. The binding of CHE to cytidine could be characterized by the hypochromic and bathochromic effects in the absorption bands, and the quenching of fluorescence intensity. The spectral data were fit by linear analysis, yielding a binding constant of 2.49 × 10 4 L mol −1at 25 °C of CHE and cytidine, and a van’t Hoff enthalpy of −20.02 kJ/mol for the exothermic interaction in the standard state. In addition, with Δ r G M Θ = − 25.09 kJ / mol and Δ r S m Θ = 17.01 J / mol K , the interactions should be entropy-driven.