Quantum chemical QSAR study of flavones and their radical-scavenging activity

Abstract

Flavonoid antioxidants act as scavengers of free radicals by rapid donation of a hydrogen atom. This quantitative structure-activity relationship ( QSAR) study of flavones was carried by using selected quantum chemical descriptors. PM3 calculations performed by MOPAC 2000 associated with Cache pro. Molecular weight, dielectric energy (kcal/mole), total energy (Hartree), heat of formation (kcal/mole), highest unoccupied molecular orbital (HOMO) energy (eV), lowest unoccupied molecular orbital (LUMO) energy (eV), log P, molar refractivity (MR), hardness (eta), softness (S), chemical potential (mu), electrophilicity index (omega), etc. were tested as descriptors, and various QSAR models were constructed. The best-fit model (r(CV)(2) = 0:92, r(2) =0:96) involved heat of formation, log P, MR, and molecular weight. The overall study indicates that steric bulk and solvation are mainly responsible for the radical scavenging activity of flavones.