Understanding / Comprendre RESEARCH 091 UV, our best enemies Ultra-violets, and especially UV-B, are mandatory to our health as they participate to vitamin D synthesis, but they are also likely to damage skin cells. On top of their pro-inflammatory effect, UV have a direct and indirect mutagenic effect via ROS production. We therefore need to defend against them. sans SPF ainsi que des corneum and stands as have absorbed UV. This In order to protect the skin normalisateurs de bronzage the first defense, and delayed “dark sun” effect from UV-generated ROS, it pour assurer la protection melanin, a pigment located may cause DNA alterations is possible to scavenge them naturelle de la peau. above keratinocyte nuclei (Figure 1C). by using antioxidants such thus protecting their DNA To address this topic, as Ascorbosilane (silanol The use of filters (Figure 1A, B). Exsymol developed actives of vitamin C). One can also blocks UV but also Skin tan is therefore the that have affect the skin’s protect cell DNA with a prevents their positive body’s natural protection natural filters such as genoprotector active and effects. The reduction of the against UV. However, Entadine that limits ROS protect cell membranes with UV negative impact reduces melanogenesis may be production and prevents actives such as Alistin that their genotoxic effect as well modulated by aging or by a the “dark sun” effect reduces lipid peroxides. as the number and the effect damaged DEJ and cause the (Figure 2A, B), Tyrosilane that Exsymol offers a whole range of ROS. apparition of stains. favors melanin production, or of SPF-free photoprotector Skin has two natural However, these natural filters Sirhamnose that normalizes actives together with tan UV-absorbing filters: are imperfect as they release melanogenesis by restoring normalizers to ensure the skin urocanic acid in the stratum ROS and energy once they the DEJ (Figure 2C, D). natural protection. ■ FIGURE 2 EFFETS DES UV SUR LA PEAU EFFECTS OF UV ON SKIN A) EFFET DIRECT DES UV. MICROPHOTOGRAPHIES D’ÉPIDERMES RECONSTRUITS EXPOSÉS AUX UV-B EN PRÉSENCE OU EN ABSENCE D’UN ACTIF GÉNOPROTECTEUR (ENTADINE). LES NOYAUX DONT L’ADN EST ENDOMMAGÉ APPARAISSENT EN VERT. B) EFFET RETARD « SOLEIL NOIR ». MICROPHOTOGRAPHIES DE MÉLANOCYTES 2H APRÈS EXPOSITION À DES UV. LES NOYAUX DONT L’ADN EST ENDOMMAGÉ APPARAISSENT EN VERT. C) MICROPHOTOGRAPHIES D’EXPLANTS EXPOSÉS AU KGF (QUI INDUIT UNE SURPRODUCTION DE MÉLANINE QUAND LA JDEEST ENDOMMAGÉE). LA PRODUCTION DE MÉLANINE EST NORMALISÉE QUAND LA JDE EST RÉPARÉE. D) PHOTO VISIA RBX BROWN D’UNE PATIENTE AVANT ET APRÈS 28 JOURS D’UN TRAITEMENT VISANT À RESTAURER LA JDE. A) DIRECT EFFECTS OF UV. MICROPHOTOGRAPHS OF RECONSTRUCTED EPIDERMIS EXPOSED TO UV-B IN THE PRESENCE OR IN THE ABSENCE OF A GENOPROTECTOR ACTIVE (ENTADINE). NUCLEI WITH DAMAGED DNA APPEAR IN GREEN. B) “DARK SUN” DELAY EFFECT. MICROPHOTOGRAPHS OF MELANOCYTES 2H AFTER EXPOSURE TO UV LIGHT. NUCLEI WITH DAMAGED DNA APPEAR INREEN.G C) MICROPHOTOGRAPHS OF EXPLANTS EXPOSED TO KGF (WHICH INDUCES A MELANIN OVERPRODUCTION WHEN THE DEJ IS DAMAGED).MELANIN PRODUCTION IS NORMALIZED WHEN THE DEJ IS RESTORED. D) VISIA RBX BROWN PICTURES OF A PATIENT BEFORE AND AFTER A 28 DAYS TREATMENT FOR RESTORING THE DEJ. The global information on cosmetics & fragrances July / August 2021- N°70