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Idebenone is an antioxidant lower molecular weight analogue of coenzyme Q10. Previously, idebenone was shown to be a very effective antioxidant in its ability to protect against cell damage from oxidative stress in a variety of biochemical, cell biological, and in vivo methods, including its ability to suppress sunburn cell (SBC) formation in living skin. However, no clinical studies have been previously conducted to establish the efficacy of idebenone in a topical skincare formulation for the treatment of photodamaged skin. In this nonvehicle control study, 0.5% and 1.0% idebenone commercial formulations were evaluated in a clinical trial for topical safety and efficacy in photodamaged skin. Forty-one female subjects, aged 30–65, with moderate photodamaged skin were randomized to use a blind labelled (either 0.5% or 1.0% idebenone in otherwise identical lotion bases) skincare preparation twice daily for six weeks. Blinded expert grader assessments for skin roughness/dryness, fine lines/wrinkles, and global improvement in photodamage were performed at baseline, three weeks and six weeks. Electrical conductance readings for skin surface hydration and 35 mm digital photography were made at baseline after six weeks. Punch biopsies were taken from randomly selected subjects, baseline and after six weeks, and stained for certain antibodies (interleukin IL-6, interleukin IL-1b, matrixmetalloproteinase MMP-1, collagen I) using immunofluorescence microscopy. After six weeks’ use of the 1.0% idebenone formula, a 26% reduction in skin roughness/dryness was observed, a 37% increase in skin hydration, a 29% reduction in fine lines/wrinkles, and a 33% improvement in overall global assessment of photodamaged skin. For the 0.5% idebenone formulation, a 23% reduction in skin roughness/dryness was observed, a 37% increase in skin hydration, a 27% reduction in fine lines/wrinkles, and a 30% improvement in overall global assessment of photodamaged skin. The immunofluorescence staining revealed a decrease in IL-1b, IL-6, and MMP-1 and an increase in collagen I for both concentrations. [ABSTRACT FROM AUTHOR]

Topical applications of skin care products containing antioxidants have become increasingly popular. Numerous studies have elucidated the biological effects of these substances. General antiaging effects, anti-inflammatory properties, photoprotective properties, and prevention of ultraviolet (UV) immunosuppression have been documented. However, a standardized method to characterize and compare the properties and oxidative stress protection capacity of antioxidants was lacking. A multistepin vitroprocess utilizing a variety of biochemical and cell biological methods combined within vivostudies was designed to compare the oxidative stress protective capacity of commonly used antioxidants. Data were presented for L-ascorbic acid, dl-alpha-tocopherol, kinetin, dl-alpha lipoic acid, ubiquinone, and idebenone. Methods included using UV-induced radical trapping/scavenging capacity measured by photochemiluminescence, pro-oxidative systems (LDL-CuSO4, microsome-NADPH/ADP/Fe3+) with measurement of primary and secondary oxidation products, UVB irradiation of human keratinocytes, andin vivoevaluation, using the human sunburn cell (SBC) assay. Correlation and trends betweenin vitroandin vivoresults were established, and the standardized test protocol was used to quantify oxidative stress protection capacity of antioxidants. Summarizing and totaling the data equally weighted for each oxidative stress study, the overall oxidative protection capacity scores of 95, 80, 68, 55, 52, and 41 were obtained for idebenone, dl-alpha tocopherol, kinetin, ubiquinone, L-ascorbic acid, and dl-alpha lipoic acid, respectively. The higher the score, the more effective the overall oxidative stress protection capacity of the antioxidant became. This multistep protocol may serve as a standard in investigating and comparing new putative antioxidants for topical use as well as a valuable tool to assess the anti-inflammatory properties, photoprotective properties, and prevention of UV immunosuppression of topical antioxidants. [ABSTRACT FROM AUTHOR]