Effect of functional groups on antioxidant properties of substituted selenoethers

Abstract

Selenoethers attached to functional groups through propyl chain viz., bis(3-carboxypropyl)selenide (SeBA), bis(3-hydroxypropyl)selenide (SePOH) and bis(3-aminopropyl)selenide dihydrochloride (SePAm), have been examined for their ability to inhibit peroxyl radical mediated DNA damage, peroxyl radical scavenging ability and glutathione peroxidase (GPx) like activity. The DNA damage was monitored by gel electrophoresis, bimolecular rate constants for scavenging of model peroxyl radical were determined by pulse radiolysis and the GPx activity was followed by their ability to reduce hydrogen peroxide in the presence of glutathione utilizing NADPH decay and HPLC analysis. Among these compounds, SeBA showed maximum DNA protecting activity and it was also the most efficient in scavenging peroxyl radicals with the highest GPx mimicking activity. Quantum chemical calculations confirmed that SeBA with the highest energy level of HOMO (highest occupied molecular orbital) is the easiest to undergo oxidation and therefore exhibits better radical scavenging, GPx mimicking and DNA protecting activity than SePOH or SePAm.

Synthesis, characterization, structures and GPx mimicking activity of pyridyl and pyrimidyl based organoselenium compounds

“…Relative decay of reduced glutathione (GSH) with respect to formation of oxidized form of glutathione (GSSG) was monitored by absorption detection [37]. In a typical experiment oxidation of the GSH (160 mM) was initiated by addition of H 2 O 2 (320 mM) in the presence of an organoselenium compound (32 mM) and incubated for 5 min at room temperature.…”

Effect of alkyl chain length on one-electron oxidation of bis(alkyl carboxylic acid) selenides: implication on their antioxidant ability

“…Further, similar experiments with 5 mM SeBA, generated transient absorption spectrum with absorption maxima at 320 nm and 490 nm at 1 ms aer the pulse (Fig. [15][16][17][18][19][20][21] The absorbance at 360 nm can be due to the selenuranyl radical (pSerOH) formed by OH adduct formation at the selenium centre or it may be due to intramolecularly stabilized selenium monomer radical species formed between the selenium centred radical cation and the negatively charged oxygen of the carboxylate functional group. In general, selenium radicals form dimer radical species and the yield of such species increases with increase in the concentration of the selenium compound.…”

“…[15][16][17][18][19][20][21] The oxidation mechanism and stability of this selenium centred radical cation is greatly inuenced by the presence of different functional groups. 15 The higher antioxidant ability was correlated with energy level of highest occupied molecular orbital (HOMO) of the moderately electron donating carboxylate ion. 15 The higher antioxidant ability was correlated with energy level of highest occupied molecular orbital (HOMO) of the moderately electron donating carboxylate ion.…”

“…[15][16][17][18][19][20][21] Among the series of aliphatic selenoethers containing different functional groups and varying chain lengths, the carboxylic functionalized derivatives showed higher activity compared to other substituted derivatives. 15 To gain further insight on the effect of alkyl chain length on the mechanism and the nature of the transients formed during the free radical scavenging by the carboxylic acid group substituted selenides, detailed pulse radiolysis studies have been carried out on seleno bis(ethanoic acid) (SeEA), seleno bis(propanoic acid) (SePA) and seleno bis(butanoic acid) (SeBA) (Scheme 1). 15 To gain further insight on the effect of alkyl chain length on the mechanism and the nature of the transients formed during the free radical scavenging by the carboxylic acid group substituted selenides, detailed pulse radiolysis studies have been carried out on seleno bis(ethanoic acid) (SeEA), seleno bis(propanoic acid) (SePA) and seleno bis(butanoic acid) (SeBA) (Scheme 1).…”

Synthesis, characterization, structures and antioxidant activity of nicotinoyl based organoselenium compounds

“…In HPLC assay GPx like activity was monitored by following the ratio of the depletion in the concentration of glutathione reduced (GSH) and increase in the concentration of oxidized glutathione (GSSG). In our model system [30], reaction was initiated by adding H 2 O 2 (320 mM) to a mixture of GSH (160 mM) and organoselenium compounds (10 mM) as catalysts and leaving it for 5 min. The GSH and GSSG were separated by HPLC on a reverse phase C18 column using a mobile phase of aqueous solution containing 2% methanol in 0.1% trifluoroacetic acid (TFA) and detected at 210 nm.…”