The Effect Of Polarity Of Environment On The Antioxidant Activity Of Carotenoids

Four density functionals and the C-PCM solvation model were used in the DFT calculations of the oxidation potentials of four carotenoids in cyclohexane, dichloromethane and water. The values obtained using M06-2X + D3 density functional fit the experimental data the best. The calculated oxidation potentials of the carotenoids decrease with increasing the polarities of the solvents, the difference being as large as 0.6 V. These behaviors are independent of the symmetries and chain lengths of the carotenoids. The results of this study are very important in the design of supramolecular carotenoid complexes because the antioxidant activities of carotenoids are oxidation potential dependent.