Electrochemical Study of Antioxidant Regeneration Mechanisms – Application in Dermocosmetics.
Résumé
Oxidative stress is associated to the massive generation of reactive oxygen species inducing fast oxidative reactions in chain. To overcome this problem, reasonable supplementations of antioxidants are widely practiced, mostly based on empirical protocols. An electrochemical process is proposed to choose the best molecules association inducing the greatest antioxidant capacity, by coupling homogeneous or heterogeneous catalytic reactions involving antioxidants with an electrochemical step. Cyclic voltammetry and constant potential electrolysis experiments were used to highlight regeneration reactions induced by specific associations of hydrophilic and lipophilic antioxidants in homogeneous medium or at liquid/liquid interface. Results showed that N-Acetyl-L-Cysteine (NAC) was effectively regenerated by both ascorbic acid (AA) and ascorbyl glucoside (AA-2G) but not by ascorbyl phosphate magnesium (AA-2P). The antioxidant properties of alpha-tocopherol also increased to 40% when associated with AA. The process was successfully applied for the first time to the study of simple emulsions. Formulations involving NAC and AA-2G presented the highest synergic effect, the antioxidant capacity being amplified by more than 35%. On the other hand no catalytic mechanism was observed when introducing three antioxidants in the cream because it induced too low reaction kinetics. This electrochemical process can thus be exploited as a tool for the optimisation of “anti-aging” dermocosmetic formulations.
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