| Autor: |
Yu M; Department of Chemistry and Biochemistry, Auburn University , Auburn, Alabama 36849, United States., Ward MB; Department of Chemistry and Biochemistry, Auburn University , Auburn, Alabama 36849, United States., Franke A; Department of Chemistry and Pharmacy, University Erlangen-Nuremberg , 91058 Erlangen, Germany., Ambrose SL; Department of Chemistry and Biochemistry, Auburn University , Auburn, Alabama 36849, United States., Whaley ZL; Department of Chemistry and Biochemistry, Auburn University , Auburn, Alabama 36849, United States., Bradford TM; Department of Chemistry and Biochemistry, Auburn University , Auburn, Alabama 36849, United States., Gorden JD; Department of Chemistry and Biochemistry, Auburn University , Auburn, Alabama 36849, United States., Beyers RJ; Auburn University Magnetic Resonance Imaging Research Center , Auburn, Alabama 36849, United States., Cattley RC; Department of Pathobiology, College of Veterinary Medicine, Auburn University , Auburn, Alabama 36849, United States., Ivanović-Burmazović I; Department of Chemistry and Pharmacy, University Erlangen-Nuremberg , 91058 Erlangen, Germany., Schwartz DD; Department of Anatomy, Physiology, and Pharmacology, College of Veterinary Medicine, Auburn University , Auburn, Alabama 36849, United States., Goldsmith CR; Department of Chemistry and Biochemistry, Auburn University , Auburn, Alabama 36849, United States. |
| Abstrakt: |
The overproduction of reactive oxygen species has been linked to a wide array of health disorders. The ability to noninvasively monitor oxidative stress in vivo could provide substantial insight into the progression of these conditions and, in turn, could facilitate the development of better diagnosis and treatment options. A mononuclear Mn(II) complex with the redox-active ligand N,N'-bis(2,5-dihydroxybenzyl)-N,N'-bis(2-pyridinylmethyl)-1,2-ethanediamine (H 4 qtp2) was made and characterized. A previously prepared Mn(II) complex with a ligand containing a single quinol subunit was found to display a modest T 1 -derived relaxivity response to H 2 O 2 . The introduction of a second redox-active quinol both substantially improves the relaxivity response of the complex to H 2 O 2 and reduces the cytotoxicity of the sensor but renders the complex more susceptible to transmetalation. The addition of H 2 O 2 partially oxidizes the quinol subunits to para-quinones, concomitantly increasing the r 1 from 5.46 mM -1 s -1 to 7.17 mM -1 s -1 . The oxidation of the ligand enables more water molecules to coordinate to the metal ion, providing an explanation for the enhanced relaxivity. That the diquinol complex is only partially oxidized by H 2 O 2 is attributed to its activity as an antioxidant; the complex can both catalytically degrade superoxide and serve as a hydrogen atom donor. |
