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

Introduction

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.

Objectives

The aim was to evaluate in vivo by a non-invasive study 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).

Materials and method

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.

Results

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).

Conclusion

This non-invasive 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.

Keywords

Photoprotection, immunosuppression, antioxidant.

Fontbonne A.^1,2, Abric E.¹, Moga A.³, Callejon S.^1,2, Giraud F.^1,2, Garin C.¹, Ardiet N.¹, Cadars B.^1,2, Graizeau C.^1,2 and Trompezinski S.^1,2

¹NAOS Group, Aix-en-Provence, France

²NAOS ILS, Aix-en-Provence, France

³QIMA Synelvia, Labège, France

Arnaud Fontbonne^1,2; Elise Abric²; Alain Moga³; Sylvie Callejon^1,2; Félix Giraud^1,2; Cécile Garin²; Nathalie Ardiet²; Benoît Cadars^1,2; Aurélie Guyoux²; Sandra Trompezinski^1,2

¹NAOS Institute of Life Science, Aix-en-Provence, France

²NAOS Group, Research & Development Department, Aix-en-Provence, France

³QIMA Synelvia, Labège, France