Substituent Effects on the Radical Scavenging Activity of Isoflavonoid.
Int J Mol Sci
; 20(2)2019 Jan 18.
Article
em En
| MEDLINE
| ID: mdl-30669260
ABSTRACT
Understanding the role of substituents is of great importance for the preparation of novel phenolic compounds with enhanced antioxidative properties. In this work, the antioxidative activity of isoflavonoid derivatives with different substituents placed at the C2 position was determined by density functional theory (DFT) calculations. The bond dissociation enthalpy (BDE), ionization potential (IP), and proton affinity (PA) related to hydrogen atom transfer (HAT), single electron transfer-proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET) mechanisms were calculated. The strongest antioxidative group of isoflavonoid is not altered by the substituents. Excellent correlations were found between the BDE/IP/PA and Hammett sigma constants. Equations obtained from linear regression can be useful in the selection of suitable candidates for the synthesis of novel isoflavonoids derivatives with enhanced antioxidative properties. In the gas and benzene phases, the electron-donating substituents would enhance the antioxidative activity of isoflavonoids via weakening the BDE of 4'-OH. In water phase, they will reduce the antioxidative by strengthening the PA of 7-OH. Contrary results occur for the electron-withdrawing groups. In addition, the electronic effects of substituents on the BDE/IP/PA have also been analyzed.
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Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Sequestradores de Radicais Livres
/
Isoflavonas
Idioma:
En
Revista:
Int J Mol Sci
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
China