Tyrosinase-related Protein-1 Protein Research Articles

Echinochrome A Inhibits Melanogenesis in B16F10 Cells by Downregulating CREB Signaling.

Excessive increase in melanin pigment in the skin can be caused by a variety of environmental factors, including UV radiation, and can result in spots, freckles, and skin cancer. Therefore, it is important to develop functional whitening cosmetic reagents that regulate melanogenesis. In this study, we investigated the effects of echinochrome A (Ech A) on melanogenesis in the B16F10 murine melanoma cell line. We triggered B16F10 cells using α-MSH under Ech A treatment to observe melanin synthesis and analyze expression changes in melanogenesis-related enzymes (tyrosinase, tyrosinase-related protein 1 (TYRP1), and tyrosinase-related protein 2 (TYRP2)) at the mRNA and protein levels. Furthermore, we measured expression changes in the microphthalmia-associated transcription factor (MITF), CREB, and pCREB proteins. Melanin synthesis in the cells stimulated by α-MSH was significantly reduced by Ech A. The expression of the tyrosinase, TYRP1, and TYRP2 mRNA and proteins was significantly decreased by Ech A, as was that of the MITF, CREB, and pCREB proteins. These results show that Ech A suppresses melanin synthesis by regulating melanogenesis-related enzymes through the CREB signaling pathway and suggest the potential of Ech A as a functional agent to prevent pigmentation and promote skin whitening.

GIF-2209, an Oxindole Derivative, Accelerates Melanogenesis and Melanosome Secretion via the Modification of Lysosomes in B16F10 Mouse Melanoma Cells.

Melanogenesis and melanosome secretion are regulated by several mechanisms. In this study, we found that the oxindole derivative GIF-2209 accelerated melanogenesis associated with the discrimination in the expression and intracellular distributions of two melanogenic enzymes, tyrosinase (TYR) and tyrosinase-related protein-1 (TYRP-1). GIF-2209 upregulated the expression of TYR via a microphthalmia transcription factor (MITF)-independent mechanism, leading to high expression of protein. In contrast, GIF-2209 did not alter the mRNA levels of TYRP-1 and suppressed its protein levels. GIF-2209 induced the dissociation of TYR from TYRP-1 but did not alter the association between TYR and CD63, a melanosome and lysosome marker. The protein levels of CD63 were also upregulated by GIF-2209. GIF-2209 induced lysosome expansion and redistribution in all areas of the cytosol, accompanied by autophagy acceleration (upregulation of LC3BII protein levels and downregulation of p62 protein levels). In addition, GIF-2209 stimulated the secretion of melanosomes containing high levels of TYR, TYRP-1, and CD63 proteins. The GIF-2209 mediated melanosome secretion was sensitive to the lysosome inhibitor chloroquine. These results suggest that GIF-2209 may activate lysosomal functions with TYR gene expression, while it accelerates melanosome secretion, which finally leads to the depletion of intracellular melanogenic enzyme, especially TYRP-1 protein.

Human TYRP1: Two functions for a single gene?

In the animal kingdom, skin pigmentation is highly variable between species, and it contributes to phenotypes. In humans, skin pigmentation plays a part in sun protection. Skin pigmentation depends on the ratio of the two pigments pheomelanin and eumelanin, both synthesized by a specialized cell population, the melanocytes. In this review, we explore one important factor in pigmentation: the tyrosinase-related protein 1 (TYRP1) gene which is involved in eumelanin synthesis via the TYRP1 protein. Counterintuitively, high TYRP1 mRNA expression is associated with a poor clinical outcome for patients with metastatic melanomas. Recently, we were able to explain this unexpected TYRP1 function by demonstrating that TYRP1 mRNA sequesters microRNA-16, a tumor suppressor miRNA. Here, we focus on actors influencing TYRP1 mRNA abundance, particularly transcription factors, single nucleotide polymorphisms (SNPs), and miRNAs, as they all dictate the indirect oncogenic activity of TYRP1.

Understanding the role of extracts from sea buckthorn seed residues in anti-melanogenesis properties on B16F10 melanoma cells.

The hydroalcoholic extract of sea buckthorn (Hippophae rhamnoides L.) seed residues (HYD-SBSR) is a potential skin whitening agent. To test this material as a potential skin whitening agent, we identified and quantified the main chemical constituents of HYD-SBSR by using ultra-performance liquid chromatography coupled with quadruple time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS) and ultra-high performance liquid chromatography coupled with triple quadruple mass spectrometry (UPLC-QQQ-MS). The anti-melanogenesis properties of HYD-SBSR on B16F10 mouse melanoma cells were analysed and the mechanism was measured on both the transcriptional and translational levels. About 24 compounds were identified. Kaempferol and its derivatives were the main compounds with a concentration of about (2796.22 ± 31.55) μg per g DW. The following order among the detected compounds was observed: quercetin and its derivatives > isorhamnetin and its derivatives > procyanidins. HYD-SBSR has a strong antioxidant activity but with a slight cytotoxic effect on B16F10 when treated with 45.45 μg mL-1 and 4.55 μg mL-1 respectively, for 48 h. HYD-SBSR has been found to significantly decrease melanin content (P < 0.01) in 24 h, 48 h, and 72 h. Additionally, strong inhibitory extracellular tyrosinase activities and decreasing intracellular tyrosinase activities were also observed (P < 0.01). HYD-SBSR shows inhibitory effects on the expression of tyrosinase (TYR) and tyrosinase-related protein 1 (TRP-1), and the secretion of TYR and TRP-1 proteins in cell lines. The protein levels of tyrosinase-related protein 2 (TRP-2) and microphthalmia-associated transcription factor (MITF) showed no significant difference. HYD-SBSR may inhibit melanin synthesis by decreasing the tyrosinase activity and down-regulating the expression of TYR and TRP-1 which were probably induced by other transcriptional factors rather than MITF.

The Effect of Butin on the Vitiligo Mouse Model Induced by Hydroquinone

Vernonia anthelmintica (L.) Willd has been traditionally used in the treatment of vitiligo in Uyghur medicine. This study used butin, the main component of V.anthelmintica, to study the influence on hydroquinone-induced vitiligo in mice. The animals were randomly divided into six groups: control, model, 8-methoxypsoralen (8-MOP, 4.25mg/kg), and butin (0.425, 4.25, and 42.5mg/kg) groups. The number of melanin-containing hair follicles, basal layer melanocytes, melanin-containing epidermal cells, the expression of tyrosinase (TYR) and tyrosinase-related protein-1 (TRP-1), the malondialdehyde (MDA), and cholinesterase (CHE) activity in serum were measured. Our results indicated that compared with the model group, the melanin-containing hair follicles, the expression of TYR and TRP-1 increased, the activity of CHE decreased after treatment with 8-MOP and all doses of butin (p<0.05, p<0.01), the basal layer melanocytes and melanin-containing epidermal cells increased significantly after treatment with butin 4.25 and 42.5mg/kg (p<0.05, p<0.01), and the MDA activity decreased after using butin 4.25 and 42.5mg/kg and 8-MOP (p<0.05, p<0.01). Our results support the use of butin on vitiligo, and its possible mechanisms may be related to increase the TYR and TRP-1 protein expression and decrease the activity of MDA and CHE in hydroquinone-induced vitiligo model in mice. Copyright © 2017 John Wiley & Sons, Ltd.

Melanogenic Effect of Eclipta Prostrata (L.) L.

This study was peformed to investigate the mechanism of ethanol extract of Eclipta Prostrata (L.) L. (EEP) induced melanogenesis. EEP enhanced tyrosinase activity and melanin contents of B16F10 cells. Moreover, EEP increased the protein expression of tyrosinase and tyrosinase-related protein 1 (TRP-1). But EEP did not increase the protein expression of tyrosinase-related protein 2 (TRP-2). These results suggest that melanogenesis-promoting effect of EEP was involved in regulation of tyrosinaase and TRP-1 protein, and EEP may be a potent pigmentation darkening agent in hypopigmentation condition.

A large insertion in intron 2 of the TYRP1 gene associated with American Palomino phenotype in American mink.

A number of American mink phenotypes display a range of brownish colours. One of these phenotypes, namely American Palomino (b (P) b (P) ) (AP) has been found to be associated with the tyrosinase-related protein 1 (TYRP1) gene by genotyping microsatellite markers in one sire family. Trials for amplifying the genomic DNA and cDNA at the beginning of intron 2 of AP TYRP1 revealed the presence of a large insertion of approximately eight kb. The insertion most likely disrupts different elements necessary for the splicing of intron 2 of the TYRP1 gene. In AP RNAseq data indicate, however, the presence of the wild-type (wt) transcript at very low levels and Western blot reveals three products when using an antibody raised against middle part of the TYRP1 protein. One individual from another brown mink phenotype-commercially named Dawn-was also investigated at the molecular level by long-range PCR and the same size insertion appears to be present. By this we suggest that certain modifiers of TYRP1 would induce different brown colour degradation, which results in at least two different phases of brown.

A 6-bp deletion in exon 8 and two mutations in introns of TYRP1 are associated with blond coat color in Liangshan pigs

Melanocortin receptor 1 (MC1R), Agouti signaling protein (ASIP), and Tyrosinase-related protein 1 (TYRP1) are reported critical genes that regulate pheomelanin and eumelanin synthesis in mammals. Liangshan pig is a special Chinese indigenous pig breed with two completely different coat colors, solid black and blond. In this study, we detected polymorphisms of the above three genes and assessed the relationships between the variations and coat color phenotypes in Liangshan pigs. The findings revealed that the blond phenotype of Liangshan pig was related to dominant mutations in TYRP1, but not related to mutations in MC1R or ASIP. We found three closely linked mutations in TYRP1, g.8406G>A in intron 4, g.11100A>G in intron 5, and g.17599_17604del in exon 8, that were completely associated with blond coat color in Liangshan pigs. Further analysis revealed that a 6-bp deletion mutation resulted in deletion of Met and Gly residues at positions 495 and 496 in TYRP1 protein, and altered the structure of transmembrane domain of TYRP1. Together, our findings indicated that these three mutations in TYRP1 cause the blond phenotype in Liangshan pigs.

연잎 추출물의 항산화 활성 및 멜라노마 세포(B16F10)에서 MITF, TRP-1, TRP-2, tyrosinase의 발현 저해 효과

The purpose of this study was to investigate the potential of Nelumbo nucifera G. leaf (NNL) extract as a cosmetic additive. The electron-donating ability of the NNL extract at a concentration of 1,000 μg/ml was 67.83%. In xanthine oxidase, the inhibition effect of the NNL extract was 92.7% at the same concentration. For whitening effects, tyrosinase inhibition effect of NNL extract was 42.7% at a 1,000 μg/ml concentration. The cell toxicity of the NNL extract was examined in melanoma cells (B16F10) using a 3-[4, 5–dimethyl–thiazol–2–yl]-2, 5-diphenyl-tetrazoliumbromide (MTT) assay. The cell toxicity assay revealed that the NNL extract had a toxicity of 81.61% at a concentration of 1,000 μg/ml The microphthalmia-associated transcription factor (MITF), tyrosinase related protein-1 (TRP-1), tyrosinase related protein-2 (TRP-2), and tyrosinase protein expression inhibitory effect by Western blot of NNL extract were measured by a Western blot at concentrations of 25, 50, and 100 μg/ml. At a 100 μg/ml concentration of the NNL extract, the expression of the MITF, TRP-1, TRP-2, and tyrosinase protein was decreased by 69.59%, 27.74%, 67.33%, and 67.78% respectively. The MITF, TRP-1, TRP-2 and tyrosinase mRNA expression inhibitory effect were measured by reverse transcription- polymerase chain reaction (PCR) at concentrations of 25, 50, and 100 μg/ml. GAPDH was used as a positive control. At a concentration of 100 μg/ml of the NNL extract, the expression of MITF, TRP-1, TRP-2, and tyrosinase mRNA was decreased by 67.51%, 71.36%, 85.74%, and 83.64%, respectively. These findings suggest that the NNL extract has antioxidant and whitening effects and that it has great potential as a cosmetic ingredient.

Hesperidin, A Popular Antioxidant Inhibits Melanogenesis via Erk1/2 Mediated MITF Degradation.

Regulation of melanogenesis has been the focus of treatment for hyperpigmentary skin disorders. Although hesperidin is one of the most well-known, naturally occurring flavonoids with antioxidant and anti-inflammatory effect, its anti-melanogenic effect is not known. The present study aims to determine the anti-melanogenic effect of hespiridin as well as its underlying molecular mechanisms. Melanin contents were measured in normal human melanocytes and B16F10 melanoma cells. Protein and mRNA levels of tyrosinase, microphthalmia-associated transcription factor (MITF), tyrosinase related protein-1 (TRP-1) and TRP-2 were determined. Melanogenesis-regulating signals were examined. In results, hesperidin strongly inhibited melanin synthesis and tyrosinase activity. Hesperidin decreased tyrosinase, TRP-1, and TRP-2 protein expression but increased phospho-extracellular signal-regulated kinase 1/2 (p-Erk1/2) expression. Specific inhibitor of Erk1/2 or proteasome inhibitor reversed the inhibition of melanogenesis induced by hesperidin. Taken together, hesperidin, a popular antioxidant, stimulated Erk1/2 phosphorylation which subsequently degraded MITF which resulted in suppression of melanogenic enzymes and melanin synthesis.

SNPs at miR-155 binding sites of TYRP1 explain discrepancy between mRNA and protein and refine TYRP1 prognostic value in melanoma.

Background:We previously demonstrated an inverse correlation between tyrosinase-related protein 1 (TYRP1) mRNA expression in melanoma metastases and patient survival. However, TYRP1 protein was not detected in half of tissues expressing mRNA and did not correlate with survival. Based on a study reporting that 3′ untranslated region (UTR) of TYRP1 mRNA contains two miR-155-5p (named miR-155) binding sites exhibiting single-nucleotide polymorphisms (SNPs) that promote (matched miRNA–mRNA interaction) mRNA decay or not (mismatched), we aimed to investigate the role of miR-155 in the regulation of TYRP1 mRNA expression and protein translation accounting for these SNPs.Methods:The effect of miR-155 on TYRP1 mRNA/protein expression was evaluated in two melanoma cell lines harbouring matched or mismatched miR-155–TYRP1 mRNA interaction after transfection with pre-miR-155. In parallel, 192 skin and lymph node melanoma metastases were examined for TYRP1 mRNA/protein, miR-155 and SNPs and correlated with patient survival. TYRP1 mRNA, SNPs at its 3′UTR and miR-155 were analysed by RT–qPCR, whereas TYRP1 protein was evaluated by western blot in cell lines and by immunohistochemistry in metastatic tissues.Results:The miR-155 induced a dose-dependent TYRP1 mRNA decay and hampered its translation into protein in the line with the ‘match' genotype. In melanoma metastases, TYRP1 mRNA inversely correlated with miR-155 expression but not with TYRP1 protein in the ‘match' group, whereas it positively correlated with protein but not with miR-155 in the ‘mismatch' group. Consequently, in the latter group, TYRP1 protein inversely correlated with survival.Conclusion:Polymorphisms in 3′UTR of TYRP1 mRNA can affect TYRP1 mRNA regulation by miR-155 and its subsequent translation into protein. These SNPs can render TYRP1 mRNA and protein expression nonsusceptible to miR-155 activity and disclose a prognostic value for TYRP1 protein in a subgroup of melanoma patients. These data support the interest in the prognostic value of melanogenic markers and propose TYRP1 to refine prognosis in patients with advanced disease.

노무라입깃해파리 가수분해 추출물의 멜라닌합성 저해효과

This study was aimed to investigate skin whitening effects of Nomura's jellyfish (Nemopilema nomurai) hydrolyzed extracts (NHE). The extracts were prepared through the hydrolysis of N. nomurai using commercial proteolytic enzymes such as Protamex, Alcalase, Flavourzyme and Neutrase with optimum pHs (pH 5-8) at 55℃. Their whitening activities were examined from the inhibition of melanin synthesis using B16-F1 cell lines. Among the examined samples, Neutrase-treated extract (N-NHE) showed the most significant inhibition effect on melanin synthesis by 89.9% at a concentration of 100μg/mL. This sample decreased the expression of tyrosinase and TRP-1 (tyrosinase related protein-1) proteins as well. These results suggested the potential application of NHE as whitening ingredients in cosmetic preparation.

Ultraviolet B radiation-stimulated urocortin 1 is involved in tyrosinase-related protein 1 production in human melanoma HMV-II cells

Ultraviolet B (UVB) radiation stimulates cutaneous melanin pigmentation. The melanosomal enzyme tyrosinase-related protein 1 (TRP1) is involved in the modulation of pigment production in response to this stressor. Recent molecular and biochemical analyses have revealed the presence of corticotropin-releasing factor (CRF) and urocortin 1 (Ucn1), together with their corresponding receptors, in mammalian skin. Although CRF and Ucn1 are thought to have potent effects on the skin system, their possible roles and regulations have yet to be determined fully. Our previous findings in human melanoma HMV-II cells suggest that both CRF and Ucn1 regulate TRP1 gene expression via Nurr-1/Nur77, transcription factors that constitute the nuclear receptor 4a subgroup of orphan nuclear receptors. HMV-II cells were found to express mainly Ucn1 mRNA. This study aimed to explore the effects of UVB on Ucn1 mRNA and TRP1 protein levels in HMV-II cells. UVB (30mJ/cm2) increased Nurr-1, Nur77, and Ucn1 mRNA levels. UVB also increased TRP1 protein levels. Ucn1 knockdown inhibited the UVB-induced increases in TRP1 protein levels. These data suggest that UVB-stimulated Ucn1 contributes to TRP1 production via the transcription of both Nurr-1 and Nur77. Ucn1, produced in melanoma cells, acts on melanoma cells themselves in an autocrine manner.

A premature stop codon in the TYRP1 gene is associated with brown coat colour in the European rabbit (Oryctolagus cuniculus).

Classical genetic studies in European rabbits (Oryctolagus cuniculus) suggested the presence of two alleles at the brown coat colour locus: a wild-type B allele that gives dense black pigment throughout the coat and a recessive b allele that in the homozygous condition (b/b genotype) produces brown rabbits that are unable to develop black pigmentation. In several other species, this locus is determined by mutations in the tyrosinase-related protein 1 (TYRP1) gene, encoding a melanocyte enzyme needed for the production of dark eumelanin. In this study, we investigated the rabbit TYRP1 gene as a strong candidate for the rabbit brown coat colour locus. A total of 3846 bp of the TYRP1 gene were sequenced in eight rabbits of different breeds and identified 23 single nucleotide polymorphisms (SNPs; 12 in intronic regions, five in exons and six in the 3'-untranslated region) and an insertion/deletion of 13 bp, in the 3'-untranslated region, organised in a few haplotypes. A mutation in exon 2 (g.41360196G>A) leads to a premature stop codon at position 190 of the deduced amino acid sequence (p.Trp190ter). Therefore, translation predicts a truncated TYRP1 protein lacking almost completely the tyrosinase domain. Genotyping 203 rabbits of 32 different breeds identified this mutation only in brown Havana rabbits. Its potential functional relevance in disrupting the TYRP1 protein and its presence only in brown animals strongly argue for this non-sense mutation being a causative mutation for the recessive b allele at the brown locus in Oryctolagus cuniculus.

Proton pump inhibitors as a possible cause of vitiligo: an in vivo and in vitro study

Vitiligo is an acquired depigmentation disorder of melanocytes. Recently, some clinical reports have suggested that proton pump inhibitors (PPIs) may worsen vitiligo, but their effects on melanocytes have yet to be elucidated. We investigated the effect of PPIs on melanogenesis in vivo and in vitro. We examined the effect of PPIs on melanogenesis in B16 murine melanoma cells by measuring melanin content and tyrosinase (TYR) activity. TYR and tyrosinase-related protein-1 (TRP-1) were monitored by western blotting. Finally, a PPI was applied to zebrafish embryos to investigate its in vivo effect on pigmentation. In agreement with our clinical experience of worsened vitiligo after PPI treatment, PPIs decreased both melanin content and TYR activity. Western blotting showed that PPIs decreased TYR and TRP-1 protein levels. In the zebrafish test, PPIs inhibited body pigmentation in a dose-dependent manner. These results suggest that the functional inhibition of melanization by PPIs may induce or aggravate vitiligo lesions in genetically predisposed patients.

Up‐regulation of melanin synthesis by the antidepressant fluoxetine

Fluoxetine, a member of the class of selective serotonin reuptake inhibitors, is a potent antidepressant commonly used in clinical practice. Here, we report that fluoxetine increases cellular tyrosinase (TYR) activity, enhances the protein levels of microphthalmia-associated transcription factor (MITF), TYR and tyrosinase-related protein-1 (TRP-1) and eventually leads to a dramatic increase in melanin production in both murine B16F10 melanoma cells and normal human melanocytes (NHMCs). In well-characterized C57BL/6 mouse models, systemic application of fluoxetine increased hair pigmentation by up-regulating hair follicular MITF, TYR, TRP-1 and tyrosinase-related protein-2 (TRP-2) protein levels. Using a serotonin 1A receptor (SR1A) antagonist and RNA interference (RNAi) technique, we revealed that SR1A appears to be one of the involved pathways in the fluoxetine-induced melanogenesis in B16F10 cells. These results suggest that fluoxetine may hold a significant therapeutic potential for treating skin hypopigmentation disorders, and SR1A may serve as a novel target in modulating melanogenesis.

Acteoside inhibits melanogenesis in B16F10 cells through ERK activation and tyrosinase down-regulation

Acteoside is a phenylpropanoid glycoside extracted from the leaves of Rehmannia glutinosa that displays various biological activities. In this study, we tested the effects of acteoside on tyrosinase activity and melanin biosynthesis in B16F10 melanoma cells. We also explored molecular mechanisms for the inhibition of melanogenesis observed, focusing on the signalling pathway of extracellular signal-regulated kinase (ERK). The effects of acteoside were determined using several cell-free assay systems and B16F10 melanoma cells for melanin content and tyrosinase activity. To investigate effects on melanogenic regulatory factors we performed reverse transcription polymerase chain reaction, cAMP assay and Western blot analyses. Acteoside showed an inhibitory effect on tyrosinase activity and melanin synthesis in both cell-free assay systems and cultured B16F10 melanoma cells. Acteoside decreased levels of tyrosinase, tyrosinase-related protein-1 (TRP-1) and microphthalmia-associated transcription factor (MITF) proteins, whereas it increased ERK phosphorylation. A specific ERK inhibitor, PD98059, abolished the acteoside-induced down-regulation of MITF, tyrosinase and TRP-1 proteins. The ERK inhibitor increased tyrosinase activity and melanin production and reversed the acteoside-induced decrease in tyrosinase activity and melanin content. In addition, acteoside suppressed melanogenesis induced by α-melanocyte-stimulating hormone and showed UV-absorbing effects. Acteoside decreased tyrosinase activity and melanin biosynthesis in B16F10 cells by activating ERK signalling, which down-regulated MITF, tyrosinase and TRP-1 production.

Inhibitory effect of panduratin A isolated from Kaempferia panduarata Roxb. on melanin biosynthesis

Hyperpigmentation disorders are associated with abnormal accumulation of melanin pigments, thus melanin synthesis inhibitors have been of great interest as target molecules for cosmetic and medicinal purposes. The aim of this study was to investigate the in vitro inhibitory effect of panduratin A, isolated from Kaempferia pandurata Roxb., on melanogenesis and its related enzymes such as tyrosinase, tyrosinase related protein-1 (TRP-1) and tyrosinase related protein-2 (TRP-2) in melan-a murine melanocytes. The IC(50) values of panduratin A for melanogenesis and tyrosinase were 9.6 μm and 8.2 μm, respectively, while those of arbutin as a positive control were 990 μm and 660 μm, respectively. In western blot analysis, panduratin A also significantly decreased tyrosinase, TRP-1 and TRP-2 protein levels. These results indicate that panduratin A effectively inhibits melanin biosynthesis, thus creating the possibility of developing a new skin-whitening agent.

Inhibitory effect of glyceollin isolated from soybean against melanogenesis in B16 melanoma cells

Natural products with non-toxic and environmentally friendly properties are good resources for skin-whitening cosmetic agents when compared to artificial synthetic chemicals. Here, we investigated the effect of glyceollin produced to induce disease resistance responses of soybean to specific races of an incompatible pathogen, phytophthora sojae, on melanogenesis and discussed their mechanisms in melanin biosynthesis. We found that glyceollin inhibits melanin synthesis and tyrosinase activity in B16 melanoma cells without cytotoxicity. To elucidate the mechanism of the effect of glyceollin on melanogenesis, we conducted western blot analysis for melanogenic enzymes such as tyrosinase, tyrosinase-related protein-1 (TRP-1), and TRP-2. Glyceollin inhibited tyrosinase and TRP-1 protein expression. Additionally, glyceollin effectively inhibited intracellular cAMP levels in B16 melanoma cells stimulated by alpha-melanocyte stimulating hormone (alpha-MSH). These results suggest that the whitening activity of glyceollin may be due to the inhibition of cAMP involved in the signal pathway of alpha-MSH in B16 melanoma cells.

Inhibitory Effects of Macelignan Isolated from Myristica fragrans HOUTT. on Melanin Biosynthesis

The aim of this study was to investigate the in vitro inhibitory effects of macelignan isolated from Myristica fragrans HOUTT. on melanogenesis and its related enzymes such as tyrosinase, tyrosinase-related protein-1 (TRP-1), and tyrosinase-related protein-2 (TRP-2) in melan-a murine melanocytes. The IC50 values of macelignan for melanogenesis and tyrosinase were 13 microM and 30 microM, respectively, while those of arbutin as a positive control were 990 microM and 660 microM, respectively. In Western blot analysis, macelignan also significantly decreased tyrosinase, TRP-1, and TRP-2 protein expression. These results indicate that macelignan effectively inhibits melanin biosynthesis and thus could be employed as a new skin-whitening agent.