This study was performed to determine the whitening effect of several solvent fractions of Diospyros kaki extracts. Fractions from ethanol extracts of D. kaki were prepared by a systematic fractionation procedure using hexane, ethyl acetate, butanol, and H2O. The ethyl acetate fractions were used to evaluate the inhibitory effects on tyrosinase activity and melanin synthesis in B16F10 melanoma cells. Ethyl acetate fractions suppressed the expression of tyrosinase, TRP-1 and TRP-2 in B16F10 melanoma cells. These results showed that ethyl acetate fractions of D. kaki could be developed as a skin whitening material in cosmetics.Key words : Diospyros kaki, tyrosinase, TRP-1, TRP-2, melanin *Corresponding author *Tel：+82-54-810-0320, Fax：+82-54-810-0399 *E-mail : bio115@hanmail.net This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Monoterpenoids were recently found as main biologically active compounds which is responsible for various physiological effect in goat's beard (Aruncus dioicus). Ethyl acetate extract of A. dioicus (ADE) was treated to B16F10 melanoma cells for the examination of whitening activity. MTT assay was performed to evaluate cell toxicity and the result showed that slight cell toxicity (> 10%) by over 500 μg･mL-1. Thus, 0, 5, 10, or 50 μg･mL-1 ADE was used for further experiments. We found that tyrosinase activity was decreased according to ADE concentration, and the total melanin content was also dramatically reduced. Especially with 50 μg･mL-1 ADE treatment tyrosinase activity was reduced to 35.6%, and 58.8% of melanin content was lowered. In addition, whitening related proteins including tyrosinase, tyrosinase related protein 1 (TRP1), TRP2, microphthalmia associated transcription factor (MITF) and cAMP and protein kinase A (PKA) were reduced by ADE treatment. It caused decreased phosphorylation of cAMP response binding protein (CREB) but increased phosphorylation of extracellular signal related kinase (ERK). Therefore, in this paper we would like to suggest the potent usage of A. dioicus natively grown in Ulleungdo, Korea as materials of functional cosmetics by confirming whitening activity related with melanin content.