ABSTRACTS 501 Hydroxy Dimethoxybenzyl Malonate: A Novel Anti­ (Photo)aging Concept Thomas Rudolph, Philipp Biihle, Jorn Beck, Frank Pflilcker, Karl-August Reiffen, and Heiwig Buchholz Merck KGaA, Frankfurter Strasse 250, 64293 Darmstadt, Germany Ideally, anti-(photo)aging concepts should provide maximum efficacy, perfect stability and cosmetic (formulation) elegance. The need for high efficacy paired with excellent stability appeared contradictive but was resolved by designing complete redox systems rather than antioxidants alone. We here introduce a new class of cosmetic redox pairs, each comprising the initial antioxidant plus its oxidation product The chemical properties of the oxidation product are the key to enabling the system to maintain or even increase its initial efficacy. A series of antioxidant tests were used to 'carefully characterize single redox pair components for 'comparison with traditional antioxidants such as vitamin C and E derivatives (DPPH, lipid and TEAC assays). Kinetic :studies on the photobehavior of a selected redox pair were 'carried out in cosmetic emulsions with solar simulation and monitored by UV spectroscopy and high performance liquid 1 chromatography. Hydroxy dimethoxybenzyl malonate 1 (HDBM) is a pure transparent cosmetic oil. It shows excellent 'cosmetic stability coupled with extraordinary antioxidant properties. This controlled activity can be explained well by the presence of its oxidation product hydroxy 'dimethoxybenzylidene malonate (HDBMox), which provides 'ongoing antioxidant activity plus excellent UV A absorbing properties. The redox pair described here provides the ,advanced on-demand benefit of a non-UV-absorbing photoprotector that is converted into its UV-absorbing 'equivalent upon light exposure. 4-(l-Phenylethyl)l,3-Benzenediol: A New, Highly Efficient Lightening Agent Gabriele Vielhaber, Gerhard Schmaus, Karin Jacobs, Helge Franke, Sabine Lange, Martina Herrmann, Holger Joppe, and Oskar Koch Research Cosmetic lngredients, Symrise GmbH & C',o KG, Miihlenfeld1tr. 1, 37603 Holzminden, Gennany There is an increasing world-wide demand for skin lightening active ingredients. Many common lightening ingredient'! on the market are either unsafe or ineffective at low concentrations. We therefore screened a series of hydroxy­ stilbene derivatives for tyrosinase inhibitory activity. By chemical synthesis, the structures were optimized for efficacy and stability. The final candidate, 4-( 1-phenylethyl)l,3- benzenedioL was found to be stable and to inhibit mushroom tyrosinase 22 times more effectively than kojic acid. In an assay with B 16V melanoma cells, 4-( 1-pheny!ethyl) 1,3- benzenediol was the most potent inhibitor of melanin synthesis with an IC,0 of 2µM among the compounds investigated. The lightening effect of 4-( 1-phenylethyl) 1,3- benzenediol was not due to cytotoxicity as proved by an MTT assay on B16V cells. On pigmented 3D epidermis models, 0.1% of 4-(1-phenylethyl)l,3-benzenediol led to an almost complete suppression of melanin synthesis after 14 da ys of incubation. Finally, an in vivo test on Aiian subject proved that 4-( 1-phenylethyl) 1,3-benzenediol efficiently lightens human skin at 0.5% dosage. Optimal results are achieved when 4-( 1-phenylethyl) 1,3-ben?.enediol is applied in formulations with low oil content In summary, we have demonstrated that 4-(1-phenylethyl)l,3-bemenediol 1s a potent, stable and safe skin lightener.

J. Cosmet. Sci.! 5 7, 503-510 (November/December 2006) AUTHOR INDEX TO VOLUME 57 Abdul-Malak, N., see Popa, I., 172 Abe, Y., see Iwanaga, T., 65 Abu-Jdayil, B., A facial mask comprising Dead Sea mud, 441 Ackermann, H., see Buenger, J., 342 Acosta, E. J., see Komesvarakul, N., 309 Ahrens, S., see Passel, P., 69 Alexis, A. F., Special considerations in the treatment of ethnic skin (2006 Annual Scientific Seminar), 407 Altinkurt, T., see Gontillti, 0., 465 Amos, J., see Li, W., 178 Anamandla, S., see Vinson, J., 72 Anchisi, C., Chitosan beads loaded with essential oils in cosmetic formulations, 205 Anderheggen, B., Taurine improves epidermal barrier properties stressed by surfactants-A role for osmolytes in barrier homeostasis, ] Aulmann, W., Trends in ecological science-Is there a paradigm shift? (Abstract, IFSCC), 399 Baitokova, A., see Yener, G., 487 Barford, B., see Canning, J. S., 412 Bayona, J.M., see Jover, E., 23 Beck, J., see Rudolph, T., 500 Bennaceur, K., see Popa, I., 172 Bernstein, E. F., Modern laser therapy: Theory, practice and the interface with topicals (2006 Annual Scientific Seminar), 405 Bhatt, V. D., Absorption and evaporation of volatile and potentially hazardous chemicals from human skin (2005 Annual Scientific Meeting), 189 Bhushan, B., see LaTorre, C., 37 Bielfeldt, S., Use of image anaylsis techniques for objective quantification of the efficacy of different hair removal methods, 345 Black, D., Image analysis of skin scaling using D-Squame samplers: Comparison with clinical scoring and use for assessing moisturizer efficacy (Abstract, IJCS), 17] Blaese, T. G., see Weichers, J. W., 175, 191 Blankschtein, D., see Ghosh, S. 428 Bockmiihl, D., Prebiotic cosmetics: An alternative to antibacterial products, (Abstract, IFSCC), 500 Boissy, R. E., see Hamed, S. H., 291 Bonfigli, A., see Distante, F., 499 Bonnet, I., see Kromidas, I., 343 Bonnet, S., see Hart, J., 185 Boyer, J., see Black, D., 171 Brandt, M., see Bielfeldt, S., 345 Breuer, M. M., The physical chemistry of hair fiber array-water interactions (2005 Annual Scientific Meeting), 84 Brown, K. C., Hair coloring: The next generation? (2006 Annual Scientific Seminar), 418 Brummer, M., see Muelbach, M., 341 Buchholz, H., see Rudolph, T., 500 Buenger, J., An interlaboratory comparison of methods used to assess antioxidant potentials (Abstract, IJCS), 342 Buffevant, C., see Hart, J., 185 Biihle, P., see Rudolph, T., 500 Canning, J. S., Use of digital photography and image analysis techniques to assess stratum corneum compromise in health care workers (HCW's) (2006 Annual Scientific Seminar), 412 Cannon, A. S., Water soluble photocrosslinking materials in cosmetics (2006 Annual Scientific Seminar), 435 Cardinali, M. S., see Howard, D., 439 Carlotti, M. E., Photodegradation of retinal and anti-aging effectiveness of two commercial emulsions, 261 Carson, P. A., Ethics of studies involving human volunteers. I. Historical background, 215 Ethics of studies involving human volunteers. II. Relevance and practical implementation for cosmetic scientists, 223 Carter, S., see Flower, C., 172 Chae, H. G., see Nam, G. W. 175 503