A Quantitative Structure-Activity Relationship (QSAR) study of the antioxidant activity of flavonoids

A Quantitative Structure-Activity Relationship (QSAR) study has been carried out for 27 flavonoids belonging to four different groups (isoflavons, flavons, flavonols, flavanons) to correlate and predict the inhibition of lipids peroxidation effects (antioxidant activity). The genetic algorithm (GA) and multiple linear regression analysis (MLRA) were used to select the descriptors and to generate the correlation models that relate the structural features to the biological activities. The obtained equations consist of one to four descriptors calculated from the characteristics of the molecular structures with use of DRAGON software and quantum-chemical methods. A number of molecular descriptors was obtained from the density functional theory (DFT) B3LYP/6-31G(d, p) level optimized geometries (quantum-chemical descriptors). The results of the GA-MLRA analysis show that the position of the OH groups, the magnitude of dipole moment and the shape of the molecule play an important role in inhibition of lipids peroxidation by flavonoids. The significant QSAR models were obtained with r value of 0.935 and 0.933 for basic models. The q(2) (cross validation r(2)) values and scrambling/randomization experiments also confirms the statistical significance of our models. These models are expected to be useful for screening of flavonoid antioxidants.