• YAKHAK HOEJI
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• v.52 no.6
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• pp.500-506
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• 2008

Apigenin, a natural flavonoid found in a variety of vegetables and fruits, has been shown to possess many biological functions. In this study we found that apigenin stimulated melanin synthesis in a dose-dependent manner in B16 murine melanoma cells. Since in our previous study $K^+$-$Cl^-$-cotransport (KCC) has been shown to mediate the mechanism of action of apigenin in neuronal cells, we further investigated the role of KCC in the melanogenesis-stimulating effect of apigenin in B16 cells. At nontoxic concentrations apigenin induced $Cl^-$-dependent $K^+$ efflux, a hallmark of KCC activity, which was markedly prevented by a specific KCC inhibitor R-(+)-[(2-n-butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-1H-inden-5-yl)oxy]acetic acid (DIOA). These results indicate that KCC is functionally present, and activated by apigenin in the B16 cells. In addition, the apigenin-induced stimulation of melanogenesis was also significantly inhibited by DIOA. NEthylmaleimide (NEM), a known KCC activator, induced $Cl^-$ efflux and stimulated melanogenesis in a concentration-dependent fashion. Both effects of NEM were significantly inhibited by DIOA. Taken together, these results suggest that apigenin can modulate melanogenesis through the activation of a membrane ion transporter, KCC in B16 cells. These results further suggest that apigenin may be a good candidate in the therapeutic strategy for hypopigmentation disorders, such as vitiligo.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.1 s.49
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• pp.25-33
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• 2005

Melanocytes synthesize melanin within discrete organelle termed melanosomes which are transferred to the surrounding keratinocytes and can be produced in varying sizes, numbers and densities. Skin whitening products have become increasingly popular in the past few years. The most successful natural skin whitening agents are: arbutin, vitamin C, kojic acid, and mulberry, which are all tyrosinase inhibitors. In this work, melanoston, a melanogenesis inhibitor isolated from yeast was studied to understand its mechanism of melanogenesis inhibition. It was found that melanoston was not a tyrosinase inhibitor, while when melanoston was applied to the B16 melanoma cell culture media, the intracellular tyrosinase activity was decreased by more than $30\%$. When B16 melanoma was stimulated with $\alpha$-MSH, cell morphololgy was dramatically changed to have lots of dendrites on the cell membrane surface. On the other hand, B16 was treated with $\alpha$-MSH and melanoston, simultaneously, the change of cell morphologv was not so great. This inhibitory effect of melanoston was found to be related to the inhibition of intracellar activation and transportation of tyrosinase, which was observed by irmmunostaining of B16 melanoma using anti-tyrosinase antibody. From these results, melanoston was regarded as an inhibitor to the differentiation of melanoma cells.

• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.227-233
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• 1996

Tyrosinase is an enzyme which catalyzes an enzymatic browning of some foods and in vivo synthesis of melanin. In order to produce natural and edible inhibitor of the enzyme which is expected to have whitening effect on melanogenesis, a microorganism was selected from fermented foods. It was named as NU-7, and cultured in mushroom (Lentinus edodes, Shiitake) media. Optimal media to produce tyrosinase inhibitor was formulated by varing nitrogen or carbon content. If glucose content was in a range of 3-20% and ammonium sulfate was in a range of 0-0.25%, production of inhibitor was independent of cell mass. Addition of ammonium sulfate as a nitrogen source had little effect on inhibitor production. Production of inhibitor (Y) was proportionally related to shiitake content (X) with a regression equation of Y= -0.96X$^{2}$ + 13.07X + 14.43 (R = 0.96). These results indicate that shiitake and glucose are necessary for the production of tyrosinase inhibitor. In the analysis of mycotoxin in culture broth, aflatoxin was not detected, suggesting that it would be probably edible.

• KSBB Journal
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• v.19 no.2
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• pp.118-124
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• 2004

Melanocytes synthesize melanin within discrete organelle termed melanosomes which are transferred to the surrounding keratinocytes and can be produced in varying sizes, numbers and densities. Skin whitening products have become increasingly popular in the past few years. The most successful natural skin whitening agents are: Arbutin, Vitamin C, Kojic acid, Mulberry, which are all tyrosinase inhibitors. In this work, melanoston, a melanogenesis inhibitor isolated from yeast was studied to understand its mechanism of melanogenesis inhibition. It was found that melanoston was not a tyrosinase inhibitor, while when melanoston was applied to the B16 melanoma cell culture media, the intracellular tyrosinase activity was decreased by more than 30％, When B16 melanoma was stimulated with ${\alpha}$-MSH, cell morphololgy was dramatically changed to have lots of dendrites on the cell membrane surface. On the other hand, B16 was treated with ${\alpha}$-MSH and melanoston, simultaneously, the change of cell morphology was not so great. This inhibition effect of melanoston was found to be related to the inhibition of intracellular activation and transportation of tyrosinase, which was observed by immunostaining of B16 melanoma using anti-tyrosinase antibody. From these results, melanoston was regarded as an inhibitor to the differentiation of melanoma cells.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.520-539
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• 2003

By using sequentially efficacy tests based on tyrosinase, the key enzyme of melanogenesis, then a cell line of melanocytes cultured in vitro, we have been able to detect the whitening potential of a plant extract and then to develop a new whitening Active Ingredient whose the whitening potential was confirmed on cultured melanocytes. Through a phytochemical approach, it seems that the whitening potential could be due to the "tannin" fraction of plant extract. A complementary work is planned to explain more precisely which fractions are responsible for the whitening potential and a clinical test is in progress on 30 Asian skin type volunteers to show the whitening efficacy on human volunteers.

• Korean Journal of Pharmacognosy
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• v.38 no.4
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• pp.382-386
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• 2007

Cinnamomi Cortex (Lauraceae), the dried bark of Cinnamomum cassia BLUME, has been used as traditional Chinese medicine for its stomachic, astringent, carminative, antispasmodic, antibacterial, antifungal properties. Four compounds were isolated from the MeOH extract of Cinnamomi Cortex, and their structures were identified as trans-cinnamic acid (1), ${\beta}-sitosterol$ (2), bis(2-methylheptyl)phthalate (3), coumarin (4) by comparison of their physical and spectral data with those reported in the literature. These compounds were tested melanogenesis inhibitory effect on B-16 mouse melanoma cell lines. Among them, trans-cinnamic acid (1) showed the most potent inhibitory effect on melanogenesis with $IC_{50}$ value of $13{\mu}g/ml$. Arbutin, positive control, exhibited an $IC_{50}$ value of $29{\mu}g/ml$.

• Journal of Physiology & Pathology in Korean Medicine
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• v.31 no.4
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• pp.226-232
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• 2017

In this study, ethanol extract of Epimedium koreanum Nakai(EEKN) enhanced melanogenesis by inducing expression of tyrosinase and tyrosinase-related protein-1 (TRP-1). But EEKN did not increase the protein expression of tyrosinase-related protein 2 (TRP-2). Moreover, EEKN enhanced tyrosinase activity and melanin contents of B16F10 cells. EEKN raised the expression of CREB phosphorylation and microphthalmia-associated transcription factor (MITF) as a key transcription factor for tyrosinase expression regulating melanogenesis. And PKC inhibitor H89 supressed that EEKN induced tyrosinase activity, melanin contents, and expression of tyrosinase, TRP-1. These results suggest that melanogenesis-promoting effect of EEKN was correlated with regulation of tyrosinase and TRP-1 protein through cAMP/PKC pathway.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.1
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• pp.29-34
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• 2015

Fucoidan, a fucose-rich sulfated polysaccharide derived from brown seaweed in the class Phaeophyceae, has been widely studied for its possible health benefits. However, the potential of fucoidan as a possible treatment for hyperpigmentation is not fully understood. This study investigated the effects of fucoidan on melanogenesis and related signaling pathways using Mel-Ab cells. Fucoidan significantly decreased melanin content. While fucoidan treatment decreased tyrosinase activity, it did not do so directly. Western blot analysis indicated that fucoidan downregulated microphthalmia-associated transcription factor and reduced tyrosinase protein expression. Further investigation showed that fucoidan activated the extracellular signal-regulated kinase (ERK) pathway, suggesting a possible mechanism for the inhibition of melanin synthesis. Treatment with PD98059, a specific ERK inhibitor, resulted in the recovery of melanin production. Taken together, these findings suggest that fucoidan inhibits melanogenesis via ERK phosphorylation.

• Preventive Nutrition and Food Science
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• v.2 no.4
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• pp.285-290
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• 1997

Previously, a 50% aqueous methanol extract of Galla rhois was shown to be the most potent tyrosinase inhibition activity with an {TEX}$IC_{50}${/TEX}(the concentration causing 50% inhibition of tyrosinase activity) of 0.2mg/ml of 205 crude drug extracts. To isolate tyrosinase inhibitors, the methanol extract was evaporated to a small volume in vacuo, and then partitioned stepwise with benzene and ethyl acetate(EtOAc). the EtOAc fraction was solubilized in 10% MeOH solution, and then fractionated successively by Diaion HP-20 and Sephadex LH-20 column chromatography, and preparative HPLC. Three phenolic compounds were isolated, and characterized as gallic acid(GA), methyl gallate(MG) and 1,2,3,4,6-penta-O-galloyl-$\beta$-D-glucose(PGG) by UV, IR, {TEX}${1}^H${/TEX}-&{TEX}${13}^C${/TEX}-NMR, and FAB-MS spectroscopy, PGG({TEX}$IC_{50}${/TEX}=50$\mu\textrm{g}$/ml) showed a considerable inhibitory effect against mushroom tyrosinase, while GA({TEX}$IC_{50}${/TEX}=1.6mg/ml) and MG({TEX}$IC_{50}${/TEX}=234$\mu\textrm{g}$/ml) did not show an appreciable effect. Meanwhile, MG inhibited greatly melanogenesis in a murine melanocyte cell line, Mel-Ab. MG and PGG showed typical noncompetitive inhibition patterns against mushroom tyrosinase. These results suggest that PGG and MG may be potentially useful as either anti-browning or anti-melanogenic agents in foods and cosmetics.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.28 no.1
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• pp.135-149
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• 2002

To date, research on the regulation of melanogenesis has focused on factors which affect tyrosinase, the rate-limiting enzyme in the melanogenic pathway, by searching for chemicals which competitively inhibit tyrosinase function. Many types of tyrosinase inhibitors have been developed, but no satisfactory results have been made clinically until now, To find a new whitening agent, which effectively inhibits melanogenesis, we synthesized several compounds and selected compounds by cell-based assay system. Finally, 3, 4, 5-trimethoxy cinnamaie thymol ester(TCTE, Melasolv) was selected and the effects of TCTE on melanogenesis were investigated. Treatment of mouse-derived melanocyte melan-a cells with TCTE results in a marked down-regulation of tyrosinase activity. 80% decrease of tyrosinase activity occurs with 30uM TCTE treatment for 72 hours without affecting cell growth. The inhibition of tyrosinase activity is dose-dependent and melanin content was also decreased to 40%. From the in vitro tyrosinase assay using cell extract, TCTE does not act as a direct inhibitor of the enzyme. Treatment of melan-a cultures with TCTE blocks the increase in tyrosinase activity by either forskolin, 3-isobutyl-1-methtyl-xanthine. TCTE decreased the expression of tyrosinase, TRP-1 without effects on TRP-2 protein expression through the down regulation of tyrosinase and TRP-1 mRNA. From the results of cAMP immunoassays, intracellular levels of the cyclin nucleotide are unaffected in cells treated with TCTE. The inhibitory effects of melanin synthesis were also shown in reconstitute human epidermis model by topical application. These findings suggest that TCTE can be used for studying the regulation of melanogenesis and depigmenting agent.