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Electrochemical behavior of indolone-N-oxides: Relationship to structure and antiplasmodial activity

Reybier, Karine and Nguyen, Thi Hoang Yen and Ibrahim, Hany and Perio, Pierre and Montrose, Armelle and Fabre, Paul-Louis and Nepveu, Françoise Electrochemical behavior of indolone-N-oxides: Relationship to structure and antiplasmodial activity. (2012) Bioelectrochemistry, vol. 88. pp. 57-64. ISSN 1567-5394

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Official URL: http://dx.doi.org/10.1016/j.bioelechem.2012.04.001

Abstract

Indolone-N-oxides exert high parasiticidal activity at the nanomolar level in vitro against Plasmodiumfalciparum, the parasite responsible for malaria. The bioreductive character of these molecules was investigated using cyclic voltammetry and EPR spectroelectrochemistry to examine the relationship between electrochemical behavior and antimalarial activity and to understand theirmechanisms of action. For all the compounds (37 compounds) studied, the voltammograms recorded in acetonitrile showed a well-defined and reversible redox couple followed by a second complicated electron transfer. The first reduction (−0.88 VbE1/2b−0.50 V vs. SCE) was attributed to the reduction of the N-oxide function to form a radical nitroxide anion. The second reduction (−1.65 VbE1/2b−1.14 V vs. SCE) was assigned to the reduction of the ketone function. By coupling electrochemistry with EPR spectroscopy, the EPR spectra confirmed the formation of the nitroxide anion radical.Moreover, the experiments demonstrated that a slowprotonation occurs at the carbon of the nitrone function and not at the NO function. A relationship between electrochemical behavior and indolone-N-oxide structure can be established for compounds with R1=―OCH3, R2=H, and electron-withdrawing substituents on the phenyl group at R3. The results help in the design of new molecules with more potent in vivo antimalarial activity.

Item Type:Article
Additional Information:Thanks to Elsevier editor. The original PDF of the article can be found at Bioelectrochemistry website : http://www.sciencedirect.com/science/journal/15675394
HAL Id:hal-00903927
Audience (journal):International peer-reviewed journal
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Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
French research institutions > Institut de Recherche pour le Développement - IRD (FRANCE)
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS (FRANCE)
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Deposited By: Vincent GERBAUD
Deposited On:13 Nov 2013 13:10

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