Dihydroimidazophenanthridinium (DIP)-based DNA binding agents with tuneable structures and biological activity.

Area of Science:

• Medicinal Chemistry
• Molecular Biology
• Biophysical Chemistry

Background:

• Dihydroimidazophenanthridinium cations (DIPs) are a class of compounds with potential biological activity.
• Understanding their interaction with DNA is crucial for developing new therapeutic agents.

Purpose of the Study:

• To synthesize a diverse library of DIPs.
• To characterize their DNA binding affinity and mode.
• To evaluate their cytotoxicity and explore structure-activity relationships.

Main Methods:

• One-pot synthesis of 29 DIP compounds.
• DNA binding studies using fluorescence spectroscopy to determine binding constants and free energies.
• Viscosity measurements to assess DNA structural changes.
• Cytotoxicity assays (tetrazolium dye-based microtitration).
• Molecular modeling of DNA-DIP interactions.

Main Results:

• A library of 29 structurally diverse DIPs was successfully synthesized.
• DIPs exhibited DNA binding constants ranging from 2x10^4 to 1.3x10^5 M^-1.
• Viscosity data indicated DNA intercalation, supported by molecular modeling.
• Cytotoxicity varied widely, from 0.09 to 11.7 microM.
• Molecular modeling suggested potential for both intercalation and minor-groove binding.

Conclusions:

• The synthesized DIPs effectively bind to DNA, primarily through intercalation.
• Structural modifications influence DNA binding affinity and cytotoxicity.
• These findings offer insights for designing novel, biologically active DNA-binding agents.