Structure-antioxidant activity relationships, QSAR, DFT calculation, and mechanisms of flavones and flavonols
- Zewail City of Science and Technology, Nanomaterials Lab, Center of Material Science (CMS) (Egypt)
DFT calculations were performed on nine flavones and flavonols to explain their high antioxidant activity and variations in their activity. Conformational analysis showed that only flavonols with 3-OH directed toward the B-ring are nonplanar; however, flavones and resulted radicals are planar. Hydroxyl group eligible for dissociation is the one with ortho OH directed toward it; otherwise, one of B-ring (in 2′ or 4′-position) hydroxyl group. There are two main factors responsible for stabilizing the resulted radicals and lowering the bond dissociation energy and hence there were found well correlated with the experimental activity. First, driving force resulted from the conversion of nonplanar flavonols to planar radicals accompanied by resonance toward the carbonyl group and H-bond formation with 3-OH and second, radical stabilization by H-bond with ortho hydroxyl group with resonance toward carbonyl or pyrone oxygen. All resonance and H-bonds were confirmed by spin density, bond length, and molecular orbital calculations.
- OSTI ID:
- 22936151
- Journal Information:
- Medicinal Chemistry Research (Print), Journal Name: Medicinal Chemistry Research (Print) Journal Issue: 12 Vol. 28; ISSN 1054-2523
- Country of Publication:
- United States
- Language:
- English
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