Skin photoprotection has become a real public health issue. The major role of UVA rays has long been neglected, even though their harmful effect over the long term, by notably generating oxidative stress. The aim of this in vivo study was to evaluate the photoprotective complementary efficacy of an active complex with sun filters on volunteers exposed to UVs by measuring squalene oxidation, catalase activity and trans-urocanic acid (trans-UCA). This study was conducted on 10 male volunteers. From day 0 (D0) to D2 included, the studied products were applied (2mg/cm2, twice daily) on the back of volunteers: placebo; sun filters SPF 30; the active complex (0.1% ectoine and 0.1% mannitol); sun filters SPF 30 in association with the active complex. At D3, a 2 MED UV exposition was performed and at D4, skin surface samplings were done by swabbing. Squalene oxidation and urocanic acid were measured by LC-MS. Catalase activity was assessed using resorufin which fluoresces after oxidation. Compared to non-irradiated placebo condition, UV irradiation induced squalene oxidation by 2-fold, a decrease of catalase activity by 1.5-fold and a photo-isomerization of UCA by 5-fold. Compared to the irradiated placebo, combination of ectoine and mannitol with sun filters provided a better protection of squalene oxidation (76.8%; p<0.01), catalase activity (84.4%; p<0.001) and UCA isomerization (53.9%; p<0.01). Compared to filters alone, the active complex added to filters provided significant additional protection of squalene by 26% (p<0.05), catalase activity by 31% (p<0.05) and trans-UCA synergistically by 24% (p<0.01). This in vivo study performed on specific biomarkers demonstrates the interest of combining UV filters with a biological protection to prevent UV damages induced by sun exposure such as induction of oxidation, decrease of endogenous antioxidant defence systems and induction of photo-immunosuppression.

ESDR539 - Positive contribution of active molecules combined with sun filters evaluated by in vivo biomarkers analysis

The scientific meeting of the European Society for Dermatological Research (ESDR) is held yearly, usually in September. With an international attendance of more than 1000 skin scientists from around the globe, the four-day event includes short oral presentations from peer-reviewed abstracts, keynote lectures from international experts, sponsored symposia, satellite programs, educational events as well as an important focus on posters, networking and building collaborations amongst scientists. For more information about this year’s meeting visit our website.