Tertiary amine-based glutathione peroxidase mimics: some insights into the role of steric and electronic effects on antioxidant activity


Autoria(s): Bhowmick, Debasish; Mugesh, Govindasamy
Data(s)

2012

Resumo

In this work, several tertiary amine-based diaryl diselenides were synthesized and evaluated for their glutathione peroxidase (GPx)-like antioxidant activities using hydrogen peroxide, tert-butyl hydroperoxide and cumene hydroperoxide as substrates and thiophenol (PhSH) and glutathione (GSH) as co-substrates. A comparison of the GPx-like activity of 4-methoxy-substituted N,N-dialkylbenzylamine-based diselenides with that of the corresponding 6-methoxy-substituted compounds indicates that the activity highly depends on the position of the methoxy substituent. Although the methoxy group at 4- and 6-position alters the electronic properties of selenium, the substitution at the 6-position provides the required steric protection for some of the key intermediates in the catalytic cycle. A detailed experimental and theoretical investigation reveals that the 6-methoxy substituent prevents the undesired thiol exchange reactions at the selenium centers in the selenenyl sulfide intermediates. The 6-methoxy substituent also prevents the formation of seleninic and selenonic acids. When PhSH is used as the thiol co-substrate, the 4-methoxy-substituted diselenides exhibit GPx-like activity similar to that of the parent compounds as the 4-methoxy substituent does not block the selenium center in the selenenyl sulfide intermediates from thiol exchange reactions. In contrast, the 4-methoxy substituent significantly enhances the GPx-like activity of the diselenides when glutathione (GSH) is used as the co-substrate. (C) 2012 Elsevier Ltd. All rights reserved.

Formato

application/pdf

Identificador

http://eprints.iisc.ernet.in/45693/1/tet_68-51_10550_2012.pdf

Bhowmick, Debasish and Mugesh, Govindasamy (2012) Tertiary amine-based glutathione peroxidase mimics: some insights into the role of steric and electronic effects on antioxidant activity. In: TETRAHEDRON, 68 (51). pp. 10550-10560.

Publicador

PERGAMON-ELSEVIER SCIENCE LTD

Relação

http://dx.doi.org/10.1016/j.tet.2012.09.020

http://eprints.iisc.ernet.in/45693/

Palavras-Chave #Inorganic & Physical Chemistry
Tipo

Journal Article

PeerReviewed