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Furanochromone radical cations: generation, characterization and interaction with DNA
1Laboratory of Radiation Chemistry, Shanghai Institute of Nuclear Research, Academia Sinica, P.O. Box 800-204, Shanghai 201800, PR China.
Biophysical Chemistry
|June 29, 2001
Summary
The radical cations of visnagin and khellin were identified for the first time. Visnagin’s radical cation selectively oxidizes guanine in DNA, suggesting importance in photochemotherapy.
Area of Science:
- Photochemistry
- Biophysical Chemistry
- Medicinal Chemistry
Background:
- Naturally occurring furanochromones like visnagin (VI) and khellin (KH) are used in photochemotherapy.
- Understanding their photochemical mechanisms is crucial for optimizing therapeutic applications.
Purpose of the Study:
- To generate and characterize the radical cations of visnagin and khellin.
- To investigate their reactivity with biomolecules, particularly DNA.
Main Methods:
- Laser flash photolysis and pulse radiolysis were employed to generate and detect radical cations.
- Spectroscopic techniques were used to determine radical cation lifetimes and reaction kinetics.
- Reactions with guanosine mononucleotide and DNA were studied to assess oxidation potential.
Main Results:
- The radical cations of visnagin (VI) and khellin (KH) were successfully generated and identified for the first time.
- VI radical cation exhibited a higher quantum yield for photoionization and was a more potent oxidant than KH radical cation.
- Both radical cations oxidized guanosine mononucleotide, and VI radical cation selectively oxidized guanine in DNA.
Conclusions:
- Electron transfer reactions involving furanochromone radical cations are significant.
- These findings highlight the potential role of visnagin and khellin radical cations in furanochromone-based photochemotherapy.