JOURNAL OF COSMETIC SCIENCE 22 such as a collagen (31). This gentle effect can be benefi cial in the development of useful biomaterials without any side effects. Surprisingly, a signifi cant difference in tyrosinase in- hibition was observed between fractions 1 and 2 (Figure 5). The average molecular weights of HAPA-elastin, fraction 1, and fraction 2, determined using gel fi ltration chromatogra- phy (Figure 3), were 4,700, 3,900, and 10,000 Da, respectively. The molecular weights were used to calculate the molarities of each sample. The molarities for a 10 mg/ml solution of HAPA-elastin, fraction 1, and fraction 2 were 2.1, 2.6, and 1.0 mM, respectively. Al- though the molarities of HAPA-elastin and fraction 1 at a concentration of 10 mg/ml were almost similar, HAPA-elastin showed relatively higher tyrosinase inhibition than fraction 1 did. Interestingly, fraction 2 showed relatively higher tyrosinase inhibition than HAPA- elastin and fraction 1 did, despite the low molarity of fraction 2 compared with either of them. It suggested that tyrosinase inhibition activity of elastin and elastin derivatives was not simply proportional to their molecular weight. It can be presumed that the observed difference in tyrosinase inhibition was due to the different sequences of amino acids in the various peptides and not merely due to the presence of different amino acids. It has been reported that no amino acid can, by itself, completely inhibit the activity of tyrosinase (32). Melanocytes have binding sites for the elastin-derived Val-Gly-Val-Ala-Pro-Gly (VGVAPG) hexapeptide. This hexapeptide is involved in bioactivities such as cell migration and prolif- eration (33). This may be the mechanism by which HAPA-elastin inhibited tyrosinase ac- tivity, which may subsequently promote skin cell turnover and result in whitening effects. In conclusion, HAPA-elastin is useful not only as a functional food but also as a cosmetic material, because it maintains the water content of the skin and inhibits tyrosinase activity. The fi ndings from this study may contribute to the development of better cosmetics with milder and more moisturizing effects on the skin. ACKNOWLEDGMENT We thank E&C HealthCare Ltd. and ECC Co., Ltd. for the fi nancial support to conduct this study. REFERENCES (1) C. M. Kielty, M. J. Sherratt, and C. A. Shuttleworth, Elastic fi bres, J. Cell Sci., 115, 2817–2828 (2002). (2) M. Hasegawa, T. Kawasaki, M. Saito, H. Ito, K. Okamoto, C. Arai, Y. Kashiwakura, and S. Yoshimura, Determination of aortic medial tissue elastin and collagen in stroke-prone spontaneously hypertensive rats, Nihon Ronen Igakkai Zasshi, 18(5), 336–341 (1981). (3) R. Yamaji, Development of Functional Materials for Diseases and Beauty in Women (CMC Publishing Co., Ltd. Tokyo, 2014), pp. 266–273. (4) T. Hayakawa, M. Sato, A. Saiga-Egusa, Y. Takahata, F. Morimatsu, and Y. Nomura, Effect of porcine arte- rial elastin peptide to the moisture content of mice skin, Nihon Chikusan Gakkaiho, 80(2), 215–222 (2009). (5) S. G. Harvey, J. R. Gibson, and C. A. Burke, L-cysteine, glycine and dl-threonine in the treatment of hypostatic leg ulceration: A placebo-controlled study, Pharmatherapeutica, 4(4), 227–230 (1985). (6) H. Ohara, S. Ichikawa, H. Matsumoto, M. Akiyama, N. Fujimoto, T. Kobayashi, and S. Tajima, Collagen- derived dipeptide, proline-hydroxyproline, stimulates cell proliferation and hyaluronic acid synthesis in cultured human dermal fi broblasts, J. Dermatol., 37(4), 330–338 (2010). (7) H. W. Spier and G. Pascher, Analytical and functional physiology of the skin surface, Hautarzt, 7(2), 55–60 (1956). (8) H. Sage and W. R. Gray, Studies on the evolution of elastin—I. Phylogenetic distribution, Comp. Bio- chem. Physiol. B, 64(4), 313–327 (1979).

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