Effect of Molecular Interactions on Electron‐Transfer and Antioxidant Activity of Bis(alkanol)selenides: A Radiation Chemical Study

Abstract

Understanding electron-transfer processes is crucial for developing organoselenium compounds as antioxidants and anti-inflammatory agents. To find new redox-active selenium antioxidants, we have investigated one-electron-transfer reactions between hydroxyl ((.) OH) radical and three bis(alkanol)selenides (SeROH) of varying alkyl chain length, using nanosecond pulse radiolysis. (.) OH radical reacts with SeROH to form radical adduct, which is converted primarily into a dimer radical cation (>Se∴Se<)(+) and α-{bis(hydroxyl alkyl)}-selenomethine radical along with a minor quantity of an intramolecularly stabilized radical cation. Some of these radicals have been subsequently converted to their corresponding selenoxide, and formaldehyde. Estimated yield of these products showed alkyl chain length dependency and correlated well with their antioxidant ability. Quantum chemical calculations suggested that compounds that formed more stable (>Se∴Se<)(+) , produced higher selenoxide and lower formaldehyde. Comparing these results with those for sulfur analogues confirmed for the first time the distinctive role of selenium in making such compounds better antioxidants.

3,3′-Diselenodipropionic acid immobilised gelatin gel: a biomimic catalytic nitric oxide generating material for topical wound healing application

“…GPx activity of the DSePA–gelatin conjugate was determined by NADPH–GSH–GSSG coupled assay. 38 Briefly, 30 μg ml −1 of selenium equivalent of DSePA or DSePA–gelatin conjugate was mixed with assay buffer (0.1 M Tris, pH 7.4) containing 2.1 mM GSH, 250 μM NADPH and 0.5 units per ml of GR. The reaction was initiated by adding 300 μM of cumene hydroperoxide and monitored by following a decrease in absorbance of NADPH at 340 nm as a function of time.…”

Reactivity of oxidants towards phenyl and benzyl substituted 5-selanylpentanoic acids: radiolytic and theoretical insights

“…7,8 It is considered that the physicochemical properties of selenium are quite similar to sulfur; nevertheless, their radical-mediated redox chemistry differs significantly. 1,[9][10][11][12] Radiation chemical studies on certain water-soluble aliphatic selenium compounds from one of the authors' group have shown that selenium-centered radicals exhibit extra stability and lower reactivity than analogous sulfur-centered radicals. [12][13][14][15][16] Previous antioxidant studies on selenium-bearing carboxylic acids have shown that they have higher activity, but the underlying reaction mechanism and product distribution vary considerably depending on the chain length.…”

“…1,[9][10][11][12] Radiation chemical studies on certain water-soluble aliphatic selenium compounds from one of the authors' group have shown that selenium-centered radicals exhibit extra stability and lower reactivity than analogous sulfur-centered radicals. [12][13][14][15][16] Previous antioxidant studies on selenium-bearing carboxylic acids have shown that they have higher activity, but the underlying reaction mechanism and product distribution vary considerably depending on the chain length. 13,14 Furthermore, it is worth noting that the carboxylic group, found in various naturally occurring antioxidants such as lipoic acid, plays a significant role in their activity.…”

Nanoparticle Conjugates of Selenium Compounds: Preparation, Characterisation and Electron Transfer

“…For GNP-Selenium studies, we have employed bis-2-ethanolselenide (EOH-Se-EOH) as a model SE compound and for MNP-Selenium studies we used various Se containing aminoacid derivatives such as selenoglycine derivative (SeG) and selenoserine derivative (SeS). Synthesis of selenium compounds are reported in our earlier papers [10,11]. The chemical structure of selenium compound used for GNP interaction is given in scheme 1.…”