166 Helichrysum italicum essential oil prevents skin lipids peroxidation caused by pollution and UV

Abstract

Skin is the first shield against external assaults. Chronic exposure to Ultraviolet (UV) and pollution causes oxidative stress, responsible for lipids, DNA and proteins damage which in turn generate inflammation, acne and premature skin aging. The aim of this study was to evaluate the antioxidant properties of Helichrysum italicum essential oil (HIEO). The value of 104 811.5 μmol Trolox equiv/100g. obtained in ORAC test indicated a strong ability of HIEO to absorb peroxide radical. It was also efficient in protecting liposomes from degradation by hydroxyl radical in the conjugated diene method (-73.6% degradation at 0.1%). Lipophilic vitamin E (Vit E), the main antioxidant of skin surface, is transported from blood through sebaceous glands. Its depletion is associated with increased sebum peroxidation. Using squalene as a simplified model of sebum, 0.1% and 1% HIEO better prevented squalene oxidation under ozone (O3: 19.7% and 32% protection) than Vit E at the same concentrations (18.6% and 26.9%). Under singlet oxygen (1O2) exposure, while HIEO and Vit E values were comparable at 0.1% (22% and 26.7% protection), only HIEO efficacy increased at higher concentration (42.1% at 1%). A cosmetic formula containing HIEO and Vit E showed even higher protection under O3 (29.9%) and 1O2 (59.1%) exposure suggesting a synergy between the two compounds. 51 volunteers living in urban area applied the formula twice a day onto the face for 2 months. Sebum on the forehead was collected on Day 0 (D0), D28 and D56. Between D0 and D28, squalene monoperoxide (SQOOH) decreased by 28%∗ while Vit E increased by 71%∗ (∗p<0.0001). At D56, these values tended to stabilize, suggesting that the skin antioxidant balance was restored. Taken together, these results suggest that Helichrysum italicum essential oil could protect skin from pollution and UV induced oxidative stress. Its radical scavenger properties seem complementary to that of Vit E. Their combination could better protect skin than increasing Vit E concentration alone.