Differential Partitioning of Bioantioxidants in Edible Oil–Water and Octanol–Water Systems: Linear Free Energy Relationships

Partition coefficients, PWO, of antioxidants (AOs) between edible oils and water are scarce in the literature, despite that AOs are widely used to control lipid oxidation and the oxidative stress in cells. PWO values have a great importance to predict the efficiency and distribution of bioactives at different levels of biological organization from binary oil–water systems to living cells. Here, we determined the partition coefficients, PWO, of four series of potent, natural AOs of increasing lipophilicity between vegetable oils (olive, soybean, and corn) and water and, for the sake of comparison, between octanol–water, PWOCT. Results indicate that the contribution of the −CH2 groups to the overall lipophilicity of the AO is the same irrespective of the oil employed. The PWO values were compared with PWOCT values, and linear relationships were obtained for each series of AOs. Results indicate that, in general, PWO values cannot be predicted from the PWOCT values, making necessary to determine the PWO values for each oil and antioxidant.