Electronic Description of Few Selected Flavonoids by Theoretical Study

Abstract

The electronic properties responsible for free radical scavenging and metal chelation of a set of 7 flavonoids compounds were studied. Electronic parameters were calculated using semi empirical PM3 method. The structure activity relationship of OH substitution, C2-C3 double bond, chelation site of flavonoid and related property of antioxidant efficiency, BDE, mulliken atomic charge, electron current movement among A, B and C-rings were investigated. The relative change in energy (H f ) associated with the formation of phenoxyl radicals and spin density distribution of phenoxyl radicals were determined. The complexation mechanism of seven flavonoids quercetin, morin, apigenin, naringenin, chrysin, taxifolin and fisetin with metal ions, by molecular mechanics (UFF) method was investigated. Flavonoids metal chelation site order on toxic metals Pb, Bi and Cd was investigated. The most likely chelation site for metal ion was 5-OH & 4=O group, followed by 4=O & 3-OH group and the 3'& 4' hydroxyl for all the flavonoid molecules studied. In the absence of C2-C3 double bond (taxifolin) the order of metal chelation site with metal was 3-OH & 4=O, followed by 5-OH & 4=O group and 3' & 4' hydroxyl.

Insights into the mechanisms underlying the antitumor activity of an oxidovanadium(IV) compound with the antioxidant naringenin. Albumin binding studies

“…1) with lack of conjugation between the A and B rings and a concomitant stronger separation of the HOMO and LUMO orbitals on the B and A rings. This absence of conjugation leads to a shift of the main absorption band to the blue in relation to other flavonoids [17,18].…”

Palbociclib (PD 0332991) Interaction with Kinases. Theoretical and Comparative Molecular Docking Study

“…The energy gap (ΔE=LUMO–HOMO) is a function of the reactivity of palbociclib towards its inhibitory cytotoxic activity. As ΔE decreases, the reactivity of the molecule increases, thus leading to an increase in the electron donating efficiency of the molecule [45] . Lower values of the energy difference will render good inhibitory efficiency because the energy to remove an electron from the last occupied orbital will be lower.…”

“…As ΔE decreases, the reactivity of the molecule increases, thus leading to an increase in the electron donating efficiency of the molecule. [45] Lower values of the energy difference will render good inhibitory efficiency because the energy to remove an electron from the last occupied orbital will be lower. Using the values from LUMO and HOMO, the energy gap of palbociclib is ΔE = (À 2.28 eV)-(À 5.57 eV) = 2.77 eV = 116.797 kcal/mol.…”

Aqueous Extracts from Tunisian Diplotaxis: Phenol Content, Antioxidant and Anti-Acetylcholinesterase Activities, and Impact of Exposure to Simulated Gastrointestinal Fluids

“…By chelating metal ions, phenols, such as flavonoids, generally prevent metal-catalyzed free radical generation. Flavonoids can interact with metal ions with the 3’,4’-dihydroxy group located on the B ring and the 3 or 5-hydroxy and 4-carbonyl group in the C ring [ 34 ]. The absence of correlation between flavones or flavonols and chelating activities may indicate that those hydroxyl groups are bonded to other molecules, such as carbohydrates.…”