Alpha-glucosylrutin (AGR) - An innovative antioxidant in skin protection / F. Stäb in IFSCC MAGAZINE, Vol. 3, N° 4 (10-11-12/2000)

[article]  inIFSCC MAGAZINE > Vol. 3, N° 4 (10-11-12/2000) . - p. 39-43 Titre : Alpha-glucosylrutin (AGR) - An innovative antioxidant in skin protection Type de document : texte imprimé Auteurs : F. Stäb, Auteur ; R. Wolber, Auteur ; C. Mundt, Auteur ; T. Blatt, Auteur ; K. Will, Auteur ; R. Keyhani, Auteur ; F. Rippke, Auteur ; H. Max, Auteur ; U. Schönrock, Auteur ; H. Wenck, Auteur ; I. Moll, Auteur ; E. Hölzle, Auteur ; K. P. Wittern, Auteur Année de publication : 2000 Article en page(s) : p. 39-43 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.5 Parfums et cosmétiques Résumé : For strategies of active skin protection against UV-light and reactive oxygen species (ROS), the topical application of antioxidants becomes more and more prominent (5,11). However, only some of the in vitro effective antioxidants, appear to be functional in vivo too (12). In our studies we compared physiological activities of diverse known antioxidants (e. g. Vit. E, C) versus the highly water soluble flavonoid alpha glucosylrutin (AGR). The studies were conducted in vivo on human skin and in vitro using primary cells from biopsies of human skin. In vitro results: 1) AGR can bolster and protect the intracellular thiol level and the mitochondrial membrane potential of primary keratinocytes and fibroblasts against depletion by oxidative stress. 2) AGR deminishes the oxidative stress-induced decline in the rate of DNA-synthesis, -protection and -repair. 3) AGR reduces the level of tyrosine phosphorylation and ERK1/2 activation in primary skin cells challenged by oxidative stressors (H2O2, UVA). 4) AGR protects primary human skin cells against both, UV-induced reduction in DNA- and hyaluronan- synthesis as well as against UV-induced intracellular hydroperoxide formation. In vivo results: 1) Our studies on normal human skin using UVA-induced ultraweak photon emission measurements (UPE) confirm the antioxidative potential of topical AGR in vivo. 2) After UVA-irradiation in vivo, the phosphorylation of intracellular tyrosine residues and the hydroperoxide levels are significantly enhanced in keratinocytes isolated from donors suffering from polymorphic light eruption (PLE) compared with keratinocytes from healthy donors, but can be reduced even in PLE-skin cells by topical pretreatment with AGR-preparations. 3) Comparative in vivo studies on equimolar ratios of AGR versus Parsol 1789 using reflexion spectrometry give evidence that topical AGR acts predominantly as an antioxidant and not as an UV-filter. 4) Several clinical trials and home in use tests on PLE prophylaxis and UVA-protection of healthy skin showed a significant improvement of the PLE and the UVA-erythema scores at skin sites pretreated with AGR compared with untreated or placebo treated skin sites. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=10799 [article]

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The outermost stratum corneum layer is an effective barrier against dermal uptake of topically applied micronized titanium dioxide / Frank Pflücker in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 21, N° 6 (12/1999)  

[article]  inINTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 21, N° 6 (12/1999) . - p. 399–411 Titre : The outermost stratum corneum layer is an effective barrier against dermal uptake of topically applied micronized titanium dioxide Type de document : texte imprimé Auteurs : Frank Pflücker, Auteur ; H. Hohenberg, Auteur ; E. Hölzle, Auteur ; T. Will, Auteur ; S. Pfeiffer, Auteur ; R. Wepf, Auteur ; W. Diembeck, Auteur ; H. Wenck, Auteur ; H. Gers-Barlag, Auteur Année de publication : 1999 Article en page(s) : p. 399–411 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Consommateurs -- Protection Dioxyde de titane Peau -- Soins et hygiène Produits chimiques -- Absorption Produits chimiques -- Sécurité Rubans adhésifs Index. décimale : 668.5 Parfums et cosmétiques Résumé : In order to help clarify the controversially discussed dermal uptake properties of micronized titanium dioxide (TiO ), we conducted extensive in vitro dermal absorption studies with ’Franz-type’ diffusion cells on excised porcine skin. After biopsies and chemical fixation, the overall localization of TiO in the skin was analyzed by means of transmission electron microscopy (TEM). The lateral and vertical distribution of TiO within the stratum corneum (SC) was investigated by tape stripping and subsequent scanning electron microscopy (SEM) in combination with energy dispersive X-ray analysis (EDXA). TiO was found exclusively on the outermost SC layer. The surface deposit, as displayed by TEM, featured clearly distinguishable agglomerates as well as single particles with a characteristic cubic shape and a primary particle size of about 20–50 nm. Concurrently, SEM/EDXA micrographs first showed an even distribution of TiO on the skin surface. After 10-fold stripping, however, TiO was found to be localized only in the furrows and not on the partially removed ridges of the skin surface. SEM/EDXA micrographs of the adhesive tape strips revealed a characteristic pattern of stripped material and free regions. This pattern was an imprint of the skin’s topography. Hence, tape stripping initially removed TiO and SC layers only from the ridges and not from the deeper furrows. Continued stripping increasingly yielded material from the deeper contours of the SC surface. TiO was found only in traces in the upper part of the follicle without any evidence of uptake into the follicular epithelium. This indicates that there is not any relevant penetration via the follicular route. We conclude that due to the microtopography of the skin, the strip number normally does not reflect the SC layer number. Accordingly, tape stripping results should always be interpreted with care, especially in the case of topically applied particles, as even higher numbers of subsequent strips may still sample material from the outermost SC layer of the deeper furrows, which could be interpreted falsely as penetrated material. Our results clearly demonstrate that TiO homogeneously and completely covers the outermost SC layer. It is neither delivered to the SC nor to the underlying skin layers when applied topically to porcine skin in vitro in the cosmetic vehicle used here. These findings underscore the safety of this micronized inorganic UV filter. DOI : 10.1046/j.1467-2494.1999.211924.x En ligne : https://onlinelibrary.wiley.com/doi/10.1046/j.1467-2494.1999.211924.x Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26471 [article]

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