The electrochemistry of quinizarin revealed through its mediated reduction of oxygen
Journal
Proceedings of the National Academy of Sciences of the United States of America
Journal Volume
108
Journal Issue
50
Start Page
19891
End Page
19895
ISSN
10916490
Date Issued
2011
Author(s)
Abstract
After 35 years the hunt for improved anthracycline antibiotics is unabated but has yet to achieve the levels of clinical success desired. Electrochemical techniques provide a large amount of kinetic and thermodynamic information, but the use of such procedures is hindered by issues of sensitivity and selectivity. This work demonstrates how by harnessing the mechanism of catalytic reduction of oxygen by the quinone functionality present within the anthracycline structure it is possible to study the reactive moiety in nanomolar concentration. This methodology allows electrochemical investigation of the intercalation of quinizarin into DNA and, in particular, the quinone oxidation and degradation mechanism. The reversible reduction of the quinizarin, which in the presence of oxygen leads to the formation of reactive oxygen species, is found to occur at -0.535 V (vs. SCE) pH 6.84 and the irreversible oxidation leading to the molecules degradation occurs at +0.386 V (vs. SCE) pH 6.84.
Subjects
Boron-doped diamond
Electrocatalysis
Oxygen reduction
Type
journal article