Skin-care products are known delivery systems of functional lipids that can enhance the natural defense of skin. Unsaturated lipids, e.g., linoleic acids, are more susceptible to lipid oxidation than saturated lipids. Therefore, lipid oxidation must be prevented to preserve the functionality of the unsaturated lipids in skin-care products. The antioxidant properties of two Fucus vesiculosus extracts (water extract [WE] and 80% [v/v] ethanol extract [EE]) were evaluated. Both extracts had high in vitro antioxidant properties and a high phenolic content. The antioxidant efficacy of the extracts was evaluated by addition of 0.05% and 0.1% (w/w) freeze-dried extracts to facial cream formulations. The cream was stored up to 42 days (dark, 20 C) and the oxidative stability was determined by following tocopherol consumption and development in peroxides and secondary oxidation products. The results showed that EE was able to reduce the peroxide oxidation rate from 84.8% (control without extract) to 41.3%. Furthermore, a higher efficacy was observed for EE over WE. This was most likely related to higher phenolic content, high radicalscavenging activity, and moderate metal-chelating ability. However, WE indicated regeneration of tocopherols by amphiphilic polyphenolic phlorotannins, with interfacial properties. The results show that F. vesiculosus extracts rich in antioxidative phlorotannins can play an important role in reducing lipid oxidation and maintaining the quality of cream.

OBJECTIVE: The purpose of this study was to identify an effective lipid oxidation initiator which could predict, within 1 month, the long-term oxidative stability of a prototype skincare formulation. The main purpose was to find a potential initiator not to assess oxidation stability of the formulations. METHODS: Four initiators (below) were examined in three steps: R ESULTATS: Dans l'oxygraphe, les syst emes initiateurs FeCl 2 / H 2 O 2 et FeCl 3 /acide ascorbique etaient de bons acc el erateurs de la consommation en oxyg ene. L'addition de FeCl 2 /H 2 O 2 aux prototypes de formulations n'a pas eu d'impact sur la stabilit e physique. Cependant, l'addition de FeCl 3 /acide ascorbique aux prototypes de formulations a entraîn e une s eparation des phases et le syst eme FeCl 3 /acide ascorbique a donc et e jug e inutilisable. De plus, l'addition d'AAPH ou d'AMVN a entraîn e une augmentation et une diminution de la viscosit e, respectivement.