Quaternary Hexadeca-Substituted Manganese (III) Phthalocyanine as a DNA Interacting Agent; Binding Mode and Thermodynamic Parameters

Abstract

Objective: Recently, phthalocyanines have been of interest in therapeutic applications owingto the discovery oftheir outstanding biological activities (especially efficient DNA interactions). Therefore, this study reports the preparation of a new hexadeca-substituted manganese (III) phthalocyanine (MnPc) and its water-soluble derivative (QMnPc). Materials and Methods: MnPc, bearing hexyloxy, aminated, and fluorinated groups, was synthesized via a one-step metal template mechanism and then converted into its water-soluble form by treating it with iodomethane. The phthalocyanines were characterized using Fourier-transform infrared (FT-IR) and ultraviolet visible (UV-vis) spectroscopies. Additionally, the interaction between the macromolecule QMnPc and the DNA molecule was studied using a UV-vis spectrophotometer at 310 and 338 Kelvin. Results: As DNA concentration increased, the absorbance decreased, accompanied by a bathochromic shift. This observation confirmed that the studied phthalocyanine interacted with the DNA molecule via non-bonding mechanisms (intercalation and electrostatic attraction). Moreover, the binding mode was examined by obtaining the thermodynamic parameters (entropy change (triangle S)>0, enthalpy change (triangle H)<0, and Gibbs free energy change (triangle G)<0). Conclusion: The computed positive Delta S, as well as the negative values of Delta G and Delta H, confirmed that the DNA-QMnPc interaction was spontaneous and thermodynamically favored. Therefore, macromolecule QMnPc can be considered a promising agent for medical applications.