Can nitroxides evoke the Keap1-Nrf2-ARE pathway in skin?

Maya Ben Yehuda Greenwald, Shira Anzi, Shmuel Ben Sasson, Havazelet Bianco-Peled, Ron Kohen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


Nitroxides are stable cyclic radicals of diverse size, charge, and lipophilicity. They are cell-permeative, which effectively protects cells, tissues, isolated organs, and laboratory animals from radical-induced damage. The mechanisms of activity through which nitroxides operate are diverse, including superoxide dismutase-mimetic activity, oxidation of semiquinone radicals, oxidation of reduced metal ions, procatalase-mimetic activity, interruption of radical chain reactions, and indirect modulation of NO levels. Nitroxides possess both a nucleophilic (reducing properties) and an electrophilic (oxidizing properties) nature and, therefore, they may affect different cellular pathways. In the current study, a novel mechanism of action by which nitroxides provide skin protection based on their electrophilic nature is suggested. This study shows that nitroxides may act as electrophiles, directly or indirectly, capable of activating the Keap1-Nrf2-ARE pathway in human keratinocytes (HaCaT) and in human skin (human organ culture model). The high potency of oxoammonium cations versus hydroxylamines in activating the system is demonstrated. The mechanism of action by which nitroxides activate the Keap1-Nrf2-ARE pathway is discussed. Understanding the mechanism of activity may expand the usage of nitroxides as a skin protection strategy against oxidative stress-related conditions.

Original languageAmerican English
Pages (from-to)258-269
Number of pages12
JournalFree Radical Biology and Medicine
StatePublished - Dec 2014

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© 2014 Elsevier Inc. All rights reserved.


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