Antioxidant effect of water and acetone extracts of Fucus vesiculosus on oxidative stability of skin care emulsions

Abstract

A water and an acetone extract of the Icelandic brown algae Fucus vesiculosus were evaluated as potential natural sources of antioxidant compounds in skin care emulsions. To assess their efficacy in inhibiting lipid oxidation caused by photo‐ or thermoxidation, they were stored in darkness and room temperature as control conditions, and compared to samples stored under accelerated conditions (light and room temperature, or darkness and 40°C). The presence of extracts in the skin care emulsions induced remarkable colour changes when the emulsions were exposed to light, and more extensively under high temperature. High temperature also caused greater increments in the droplet size of the emulsions. The analysis of the tocopherol content, peroxide value and volatile compounds during the storage revealed that, whereas both water and acetone extracts showed (at 2 mg/g of emulsion) protective effect against thermooxidation, only the water extract showed antioxidant activity against photooxidation.Practical applications: This research is the basis of developing natural antioxidants derived from seaweed to limit lipid oxidation in skin care products.Skin care emulsions are exposed to light (A+) or elevated storage temperatures (H0) to promote lipid oxidation during storage. Control samples are stored at ambient temperatures in the dark (A0). Two Icelandic brown alga Fucus vesiculosus extracts, water (WE) and acetone (AE) extract, were added as natural antioxidants to control lipid oxidation and ensure a stable product. Both extract (depending on concentration, 1 or 2) decreased photooxidation of skin care emulsions compared to the reference (REF) without added extract, as decreased formation of secondary volatile oxidation products was observed. However, the presence of extracts in the skin care emulsions induced remarkable colour changes during storage. Moreover, samples exposed to elevated storage temperatures increased oil droplet size and resulted in disrupted emulsion structure (syneresis) by day 35.