EFFECT OF CYCLOHEXANE AND BENZENE DIESTER ON MELANOGENESIS 185 In addition, through the use of a human tyrosinase inhibitor model for structure-based drug design, the inhibitory action of benzene diester derivative 2j on human tyrosinase was estab- lished, and thereby the whitening mechanism was also identifi ed. Similar studies on potential whitening agents other than 2j will be undertaken to identify their specifi c whitening mecha- nism. In fact, some of them are currently being tested in-vivo for whitening effects. This study on change in cytotoxicity and whitening effects deriving from the structural changes of wide-ranging compounds will contribute to future research on new non-toxic whitening agents. ACKNOWLEDGMENTS This study has been sponsored by the Chungcheonbuk-Do Regional Industry R&D Project (A001100495) in the Republic of Korea. REFERENCES (1) V. J. Hearing, Biogenesis of pigment granules: A sensitive way to regulate melanocyte function, J. Dermatol. Sci., 37, 3–14 (2005). (2) H. Ando, M. S. Matsui, and M. Ichihashi, Quasi-drugs developed in Japan for the prevention or treatment of hyperpigmentary disorders, Int. J. Mol. Sci., 22, 2566–2575 (2010). (3) V. M. Virador, N. Kobayashi, J. Matsunaga, and V. J. Hearing, A standardized protocol for assessing regula- tors of pigmentation, Anal. Biochem., 270, 207–219 (1999). (4) E. J. Land, C. A. Ramsden, and P. A. Riley, The mechanism of suicide-inactivation of tyrosinase: A substrate structure investigation, J. Exp. Med., 212, 341–348 (2007). Figure 4. Binding position of arbutin and benzene diester derivative (2j) on human tyrosinase. (A) Arbutin and (B) 2j.

JOURNAL OF COSMETIC SCIENCE 186 (5) C. A. Ramsden, M. R. Stratford, and P. A. Riley, The infl uence of catechol structure on the suicide-inactiva- tion of tyrosinase, Org. Biomol. Chem., 7, 3388–3390 (2009). (6) M. R. Stratford, C. A. Ramsden, and P. A. Riley, Mechanistic studies of the inactivation of tyrosinase by resorcinol, Bioorg. Med. Chem., 21, 1166–1173 (2013). (7) M. R. Stratford, C. A. Ramsden, and P. A. Riley, The infl uence of hydroquinone on tyrosinase kinetics, Bioorg. Med. Chem., 20, 4364–4370 (2012). (8) T. Okubo, M. Oyohikawa, K. Futaki, M. Matsukami, and A. Fujii, The inhibitory effects of 4-n-butyl-resor- cinol on melanogenesis, J. Dermatol. Sci., 10, 88 (1995). (9) O. Nerya, R. Musa, S. Khatib, S. Tamir, and J. Vaja, Chalcones as potent tyrosinase inhibitors: The effect of hydroxyl positions and numbers, Phytochemistry, 65, 1389–1395 (2004). (10) S. Khatib, O. Nerya, R. Musa, S. Tamir, T. Peter, and J. Vaya, Enhanced substituted resorcinol hydrophobic- ity augments tyrosinase inhibition potency, J. Med. Chem., 50, 2676–2681 (2007). (11) K. Tasaka, C. Kamei, S. Nakano, Y. Takeuchi, and M. Yamato, Effects of certain resorcinol derivatives on the tyrosinase activity and the growth of melanoma cells, Meth. Find. Exp. Clin. Pharmacol., 20, 99–109 (1988). (12) K. Shimizu, R. Kondo, and K. Sakai, Inhibition of tyrosinase by fl avonoids, stilbenes and related 4-substi- tuted resorcinols: Structure-activity investigations, Planta Med., 66, 11–15 (2000). (13) H. Oozeki, R. Tajima, and K. Nihei, Molecular design of potent tyrosinase inhibitors having the bibenzyl skeleton. Bioorg. Med. Chem. Lett., 18, 5252–5254 (2008). (14) K. Tsukahara, Y. Takema, S. Moriwaki, N. Tsuji, Y. Suzuki, T. Fujimura, and G. Imokawa, Selective inhibi- tion of skin fi broblast elastase elicits a concentration-dependent prevention of ultraviolet B-induced wrinkle formation, J. Invest. Dermatol.,117, 671–677 (2001). (15) M. M. Bradford, A dye binding assay for protein, Anal. Biochem., 72, 248–254 (1976).