Issue 7, 2016

Catalytic radical reduction in aqueous solution via oxidation of biologically-relevant alcohols

Abstract

Metalloenzymes that normally perform catalytic antioxidant or radical-degrading functions, as well as small-molecule complexes that mimic them, can also exert pro-oxidant or radical-forming effects depending on the identity of the terminal reductant. Because nitroxyl radicals function as redox active cocatalysts in the aerobic oxidation of alcohols, we hypothesized that catalytic radical reduction could be achieved via the oxidation of biologically-relevant alcohols. Herein we report an organoruthenium complex (Ru1) that catalyzed reduction of 2,2′-azino-bis(3-ethylbenzo-thiazoline-6-sulfonate) radical monoanion (ABTS˙) to ABTS2− in phosphate buffered saline (pH 7.4) using MeOH, EtOH, i-PrOH, serine, threonine, glucose, arabinose, methyl lactate or dimethyl malate as the terminal reductant. Replacing either the C–H or O–H groups of a –CHOH– moiety resulted in the loss of ABTS˙ reducing ability. Moreover, in conjunction with an alcohol terminal reductant, Ru1 was able to inhibit the oxidation of ABTS2− by H2O2 and horseradish peroxidase, even after multiple successive challenges with excess H2O2 or ABTS˙. Collectively, these results demonstrate that Ru1 inhibits the oxidative formation of and catalyzes the reduction of radicals in aqueous solution via oxidation of biologically-relevant alcohols.

Graphical abstract: Catalytic radical reduction in aqueous solution via oxidation of biologically-relevant alcohols

Supplementary files

Article information

Article type
Edge Article
Submitted
12 Feb 2016
Accepted
04 Mar 2016
First published
10 Mar 2016
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY-NC license

Chem. Sci., 2016,7, 4052-4058

Catalytic radical reduction in aqueous solution via oxidation of biologically-relevant alcohols

Y. Htet and A. G. Tennyson, Chem. Sci., 2016, 7, 4052 DOI: 10.1039/C6SC00651E

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