Differential partitioning of lipophilic bioantioxidants in edible oil-water and octanol-water

Partition coefficients, P_W^O, 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. P_W^O 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, P_W^O, 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, P_W^OCT. Results indicate that the contribution of the −CH₂groups to the overall lipophilicity of the AO is the same irrespective of the oil employed. The P_W^Ovalues were compared with P_W^OCT values, and linear relationships were obtained for each series of AOs. Results indicate that, in general, P_W^O values cannot be predicted from the P_W^OCT values, making necessary to determine the P_W^O values for each oil and antioxidant.