Antioxidant activity of selected o-methoxyphenols and biphenols: theoretical and experimental studies

A combination of theoretical and experimental approaches was applied to study and to explain the structure - antioxidant activity relationship for selected ortho-methoxyphenols (natural and natural-like phenols). The corresponding dimers (biphenols) possessing guai?cyl moiety were handpicked in order to study the influence of the conformation and substituents in the aromatic ring on the antioxidant activity. Chain-breaking antioxidant activities of the compounds under study were determined from the kinetic curves of bulk lipid autoxidation. Full geometry optimization of neutral molecules and their corresponding phenoxyl radicals for all compounds under study were obtained by using DFT (B3LYP/6-31+G**) calculations. Good correlation between experimental and predicted activity was achieved which is helpful for the structure-activity relationship explanation.