Studies on bio-antioxidants II. An ESR study on the antioxidant efficiency of ascorbyl palmitate in micelles†

The kinetics for the reaction of ascorbyl palmitate and 4-hydroxy-TEMPO, 4-methoxy-TEMPO or 4-hexanoyloxy-TEMPO in CTAB and SDS micelles was studied by ESR spectroscopy. It was found that the behavior of ascorbyl palmitate is remarkably different from ascorbic acid in their antioxidant activity in micelles. The predominant factors governing the activity in micelles involve the lipophilicity of the antioxidant and the oxidant, the charge type of the substrates and the concentration of the surfactant. As high as 2 × 104 fold rate variation was observed by changing the lipophilicity of the antioxidant and the microenvironment of the reaction medium.