Table of Contents
Journal of Theoretical Chemistry
Volume 2014, Article ID 740205, 9 pages
http://dx.doi.org/10.1155/2014/740205
Research Article

On the Importance of Water Molecules in the Theoretical Study of Polyphenols Reactivity toward Superoxide Anion

Institut des Sciences Moléculaires, UMR 5255, Université de Bordeaux, 351 cours de la Libération, 33400 Talence, France

Received 9 June 2014; Accepted 24 July 2014; Published 14 September 2014

Academic Editor: John R. Sabin

Copyright © 2014 Laure Lespade. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Numerous studies have shown the benefits of a diet rich in fruits and vegetables. These benefits are partly due to the radical scavenging properties of polyphenols contained in fruits and vegetables since polyphenols can fight against an excess of radicals which goes along inflammation in a certain number of diseases. This pathological state, called oxidative stress, results from the aerobic condition of human organism when OH radical, hydrogen peroxide, superoxide anion, or peroxynitrite is produced in excess. If hydrogen peroxide is easily handled by human defense against radicals, the other radicals can cause damage to biological constituents like lipids, cell membranes, and other biomolecules. This paper is devoted to the theoretical study of the interaction of superoxide anion () with a very potent radical scavenger, 1,2,4,6,8-pentahydroxynaphthalene. The importance of hydration of superoxide radical for the reactivity is analyzed. Potential energy surfaces (PES) are calculated for different number of water molecules around the radical and it is shown that the transition barrier vanishes when complete hydration with six water molecules is explicitly handled. The nature of the reactivity is determined by using the natural bond orbital (NBO) analysis.