478 JOURNAL OF COSMETIC SCIENCE penetrates the epidermal barrier and the cellular membrane of keratinocytes and/or dermal fibroblasts like estrogen, and acts as a mild estrogen agonist to stimulate HA production via binding to the beta-estrogen receptor (11). Thus, it is indicated that the increase of cutaneous HA by BE is associated with not only hydration but also the thickening and recovery of changes in elasticity and viscoelasticity of the mouse skin. BE, containing 15.2 mM L-lactate (15), hydrated mouse skin together with an increase in HA content. Generally, lactate or lactic acid is added to moisturizing formulas at more than 1% (111 mM), indicating that the content of L-lactate (15.2 mM) in BE is not sufficient to express a significant moisturizing effect. Therefore, we speculate that hydration of mouse skin by topical BE is based on a synergic action of BE and L-lactate to increase cutaneous HA. CONCLUSIONS We have found that topical application of BE restores changes in the elasticity and viscoelasticity of mouse skin, increases the HA content, hydrates and thickens mouse skin, and inhibits wrinkle formation in ultraviolet B-irradiated hairless mouse skin (unpublished data). Also, topical application of a gel formula containing 10% BE slows the decrease in elasticity of human skin. In conclusion, this study supports the theory that a quantitative change in cutaneous HA markedly affects several skin features associated with cutaneous aging (2,3). BE is expected to become a new cosmetic ingre- dient with the potential to prevent cutaneous aging through the enhancement of HA production. REFERENCES (10) (1) Y. Takema, Y. Yorimoto, M. Kawai, and G. Imokawa, Age-related changes in the elastic properties and thickness of human facial skin, Br. J. Dermato/., 131,641-648 (1994). (2) R. Tammi, U. M. Agren, A. L. Tuhkanen, and M. Tammi, Hyaluronan metabolism in skin, Prog. HiJtochem. Cytochem., 29, 1-81 (1994). (3) M. O. Longas, Evidence for structural changes in dermatan sulfate and hyaluronic acid with aging, Carbohydr. Res., 159, 127-136 (1987). (4) I. Ghersetich, T. Lotti, G. Campanile, C. Grappone, and G. Dini, Hyaluronic acid in cutaneous intrinsic aging, I,t. J. Dermato/., 33, 119-122 (1994). (5) A. Lundin, B. Berne, and G. Michaelsson, Topical retinoic acid treatment of photoaged skin: Its effects on hyaluronan distribution in epidermis and on hyaluronan and retinoic acid in suction blister fluid, Acta Derre. Ve,ereo/. (Stochh.), 72, 423-427 (1992). (6) A.M. Kligman, D. Dogadkina, and R. M. Lavker, Effects of topical tretinoin on non-sun-exposed protected skin of the elderly,J. Am. Acaa'. Dermato/., 29, 25-33 (1993). (7) T. Tadaki, M. Watanabe, K. Kumasaka, Y. Tanira, T. Karo, H. Tagami, I. Horii, T. Yokoi, Y. Nakayama, and A.M. Kligman, The effect of topical tretinoin on the photodamaged skin of the Japanese, Toho•J. Ex] . RIed., 169, 131-139 (1993). (8) J.J. Anderson, M. S. Anthony, J. M. Cline, S. A. Washburn, and S.C. Garner, Health potential of soy isofiavones for menopausal women, P,b/ic Health N,tr., 2,489-504 (1999). (9) S. Widyarini, N. Spinks, A.J. Husband, and V. E. Reeve, Isofiavonoid compounds from red clover (Trifolium pratense) protect from inflammation and immune suppression induced by UV radiation, Photochem. Photobiol., 74, 465-470 (2001). E. Q. Shyong, Y. Lu, A. Lazinsky, R. N. Saladi, R. G. Phelps, L. M. Austin, M. Lebwohl, and H. Wei, Effects of the isofiavone 4',5,7-trihydroxyisoflavone (genistein) on psoralen 1 plus ultraviolet A ra- diation (PUVA)-induced photodamage, Carci,oge,esis, 23, 317-321 (2002).

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