Radical Scavenging Potential of the Phenothiazine Scaffold: A Computational Analysis

Phenothiazines: Nrf2 activation and antioxidant effects

Phenothiazines (PTZs) are an emerging group of molecules showing effectiveness toward redox signaling and reduction of oxidative injury to cells, via the activation on Kelch-like ECH-associated protein 1/nuclear factor erythroid 2-related factor 2 (Nrf2). Although several electrophilic and indirect Nrf2 activators have been reported, the risk of "off-target" effect due to the complexity of their molecular mechanisms of action, has aroused research interest toward non-electrophilic and direct modulators of Nrf2 pathway, such as PTZs. This review represents the first overview on the roles of PTZs as non-electrophilic Nrf2 activator and free radical scavengers, as well as on their potential therapeutic effects in oxidative stress-mediated diseases. Here, we provide a collective and comprehensive information on the PTZs ability to scavenge free radicals and activate the Nrf2 signaling pathway, with the aim to broaden the knowledge of their therapeutic potentials and to stimulate innovative research ideas.

A Comprehensive Study of the Radical Scavenging Activity of Rosmarinic Acid

Rosmarinic acid (RA) is reported in separate studies to be either an inducer or reliever of oxidative stress, and this contradiction has not been resolved. In this study, we present a comprehensive examination of the radical scavenging activity of RA using density functional theory calculations in comparison with experimental data. In model physiological media, RA exhibited strong HO• radical scavenging activity with overall rate constant values of 2.89 × 1010 and 3.86 × 109 M-1 s-1. RA is anticipated to exhibit excellent scavenging properties for HOO• in an aqueous environment (koverall = 3.18 × 108 M-1 s-1, ≈2446 times of Trolox) following the hydrogen transfer and single electron transfer pathways of the dianion state. The neutral form of the activity is equally noteworthy in a lipid environment (koverall = 3.16 × 104 M-1 s-1) by the formal hydrogen transfer mechanism of the O6(7,15,16)-H bonds. Chelation with RA may prevent Cu(II) from reduction by the ascorbic acid anion (AA-), hence blocking the OIL-1 pathway, suggesting that RA in an aqueous environment also serves as an OIL-1 antioxidant. The computational findings exhibit strong concurrence with the experimental observations, indicating that RA possesses a significant efficacy as a radical scavenger in physiological environments.

Antioxidant Properties of New Phenothiazine Derivatives

Phenothiazine and its derivatives have a number of properties that contribute to their wider practical use in the production of biologically active substances, drugs, dyes, etc. Therefore, the synthesis and study of new compounds is of great relevance. The aim of this work was to investigate the antioxidant activity of a number of new phenothiazine derivatives. The patterns of electroreduction of oxygen and its radicals in the presence of phenothiazine derivatives in aqueous ethanol media were studied by voltammetry. The influence of various factors on antioxidant activity was considered by the methods of experiment planning. The optimal conditions for the manifestation of the antioxidant activity of phenothiazine derivatives have been found, which seems to be relevant since it opens up new possibilities for their further use as complex preparations with antioxidant activity, including in psychiatric practice.

ROS-Scavenging Selenofluoxetine Derivatives Inhibit In Vivo Serotonin Reuptake

While the neurochemistry that underpins the behavioral phenotypes of depression is the subject of many studies, oxidative stress caused by the inflammation comorbid with depression has not adequately been addressed. In this study, we described novel antidepressant-antioxidant agents consisting of selenium-modified fluoxetine derivatives to simultaneously target serotonin reuptake (antidepressant action) and oxidative stress. Excitingly, we show that one of these agents (1-F) carries the ability to inhibit serotonin reuptake in vivo in mice. We therefore present a frontier dual strategy that paves the way for the future of antidepressant therapies.