- Electrochemical Dimerization of Phenylpropenoids and the Surprising Antioxidant Activity of the Resultant Quinone Methide Dimers
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A simple method for the dimerization of phenylpropenoid derivatives is reported. It leverages electrochemical oxidation of p-unsaturated phenols to access the dimeric materials in a biomimetic fashion. The mild nature of the transformation provides excellent functional group tolerance, resulting in a unified approach for the synthesis of a range of natural products and related analogues with excellent regiocontrol. The operational simplicity of the method allows for greater efficiency in the synthesis of complex natural products. Interestingly, the quinone methide dimer intermediates are potent radical-trapping antioxidants; more so than the phenols from which they are derived—or transformed to—despite the fact that they do not possess a labile H-atom for transfer to the peroxyl radicals that propagate autoxidation.
- Romero, Kevin J.,Galliher, Matthew S.,Raycroft, Mark A. R.,Chauvin, Jean-Philippe R.,Bosque, Irene,Pratt, Derek A.,Stephenson, Corey R. J.
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supporting information
p. 17125 - 17129
(2018/12/04)
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- Mitigation of NADPH oxidase 2 activity as a strategy to inhibit peroxynitrite formation
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Using high throughput screening-compatible assays for superoxide and hydrogen peroxide, we identified potential inhibitors of the NADPH oxidase (Nox2) isoform from a small library of bioactive compounds. By using multiple probes (hydroethidine, hydropropidine, Amplex Red, and coumarin boronate) with well defined redox chemistry that form highly diagnostic marker products upon reaction with superoxide (O2. ), hydrogen peroxide (H2O2), and peroxynitrite (ONOO), the number of false positives was greatly decreased. Selected hits for Nox2 were further screened for their ability to inhibit ONOO formation in activated macrophages. A new diagnostic marker product for ONOO is reported. We conclude that the newly developed high throughput screening/reactive oxygen species assays could also be used to identify potential inhibitors of ONOO formed from Nox2-derived O2 and nitric oxide synthase- derived nitric oxide.
- Zielonka, Jacek,Zielonka, Monika,Verplank, Lynn,Cheng, Gang,Hardy, Micael,Ouari, Olivier,Ayhan, Mehmet Menaf,Podsiad?y, Rados?aw,Sikora, Adam,Lambeth, J. David,Kalyanaraman, Balaraman
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p. 7029 - 7044
(2016/05/11)
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