Relationship between antioxidant acidity

of several flavonols and their molecular properties

E.H. Anouar¹, K. Marakchi¹, N. Komiha¹*, OK. Kabbaj¹, Z. Dhaouadi², S. Lahmar²

¹ Laboratoire de Chimie Théorique, Faculté des Sciences, Université Mohammed V-Agdal. Rabat Morocco

² Laboratoire de Spectroscopie Atomique Moléculaire et Applications. Faculté des  Sciences,

Tunis El Manar II,1060 Tunis,Tunisie

* Corresponding author. E-mail: komiha@fsr.ac.ma

Received: 04 December 2007; revised version accepted: 17 February 2008

Abstract

    In the present work, theoretical studies were performed on the flavonols which are a class of flavonoids that use the 3-hydroxyflavone backbone such as: Kaempferol, Quercetin, Morin and Myricetin substances. Density functional calculations have been carried out using B3LYP/6-31G* approach. The variations of calculated ionization potentials, electron affinities, electronegativities, chemical hardness, chemical potentials, electrophilicities, Fukui indices, OH bond dissociation energies, proton affinities and acidities are discussed in the context of the bioreactivity for this subclass of  flavonoids. It is found that the flavonols have many similar molecular properties suggesting that the subclasses of flavonoids will possess similar trends in their bioreactivity also in complex environments.

Keywords: Flavonoids; Quercetin; Kaempferol; Morin; Myricetin; DFT; Antioxidant.