• Mass Spectrometry Letters
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• v.9 no.3
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• pp.81-85
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• 2018

In this study, the chemical composition of bacterial melanin isolated from the Streptomyces glaucescens strain was elucidated by ultra-high-resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. Ultra-high-resolution mass profiles of the microbial melanin product were acquired using a 15 Tesla FT-ICR mass spectrometer in positive and negative ion modes via electrospray ionization to obtain more complete descriptions of the molecular compositions of melanin-derived organic constituents. A mass resolving power of 500,000 (at m/z 400) was achieved for all spectra while collecting 400 scans per sample with a 4 M transient. The results of this analysis revealed that the melanin pigment isolated from S. glaucescens predominantly exhibits CHON and CHO species, which belong to the proteins class of compounds, with the mean C/O and C/N ratios of 4.3 and 13.1, thus suggesting that the melanin could be eumelanin. This analytical approach could be utilized to investigate the molecular compositions of a variety of natural or synthetic melanins. The compositional features of melanins are important for understanding their formation mechanisms and physico-chemical properties.

• Journal of Microbiology and Biotechnology
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• v.16 no.5
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• pp.667-672
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• 2006

Tyrosinase is an enzyme that catalyzes the biosynthetic pathway of melanin pigments participating in the coloring of skin, hair, and eyes, and is widely distributed in nature. The inhibitory compounds of tyrosinase have been extensively used as a cosmetic agent with a skin-whitening effect. In this paper, several plant extracts were screened using Melan-a cells for the melanin biosynthesis inhibition activity, and Idesia polycarpa was selected. A melanin biosynthesis inhibitor was isolated from I. polycarpa fruits by activity-guided fractionation, and the inhibitor was identified as 6-hydroxy-2-[[[(1-hydroxy-6-oxo-2-cyclohexenl-yl)carbonyl]oxy]methyl]phenyl$\beta$-D-glucopyranoside (idescrapin) by comparing it with reported spectral data. Idescarpin $(IC_{50}=8{\mu}g/ml)$ reduced melanin content compared with the vehicle. In addition, the inhibitory activity of idescarpin for melanin synthesis is mediated by decreasing tyrosinase protein rather than directly inhibiting the tyrosinase activity. These results suggest that idescarpin isolated from I. polycarpa fruits may be used as a skin-whitening agent.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.95-95
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• 2018

In this study, we investigated the effect of branch extracts from Vaccinium oldhamii (VOB) on melanin synthesis in B16F10 cells. VOB promoted melanin production in absence or presence of ${\alpha}$-melanocyte-stimulating hormone (${\alpha}-MSH$) in B16F10 cells. However, VOB did not affect the expression of tyrosinase and TRP-1 associated with melanin synthesis at the mRNA and protein level in B16F10. But, VOB decreased TRP-2 protein level and induced tyrosinase activation in B16F10 cells. Inhibition of tyrosinase activity and tyrosinase knockdown attenuated VOB-mediated melanin synthesis. In conclusion, it is thought that VOB may stimulate melanin synthesis through activating tyrosinase activity.

• Korean Journal of Pharmacognosy
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• v.52 no.3
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• pp.143-148
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• 2021

This study was performed to elucidate the inhibitory effects of Alveopora japonica extract on melanin synthesis by measuring the levels of cell viability, mRNA expression, tyrosinase activity, and melanin production in the B16F10 cell line. The effects of A. japonica extract on tyrosinase-related protein 1 (TYRP1), TYRP2, tyrosinase (TYR), and microphthalmia-associated transcription factor (MITF) mRNA expression levels and melanin content were determined. Quantitative real-time RT-PCR show that A. japonica extract decrease the mRNA expression levels of TYRP1, TYRP2, TYR, and MITF in B16F10 cell line, resulting in lower levels of melanin production compared to α-MSH-treated B16F10 cells. Tyrosinase activity assays reveal that A. japonica extract decrease melanin production in B16F10 cells. These results demonstrate the whitening effects of A. japonica extract on B16F10 cells; thus, A. japonica extract is a potent ingredient for skin whitening. Further research is needed on the mechanism of action of A. japonica extract. Such research will benefit not only cosmetics, but also the health food and medical industries.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.48 no.1
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• pp.65-70
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• 2022

In this study, the anti-pigmentation efficacy of Panax vietnamensis (P. vietnamensis), a ginseng native to Vietnam, was confirmed. Melanin synthesis was repressed by ethanolic extracts of P. vietnamensis in B16F10 cells, melanocytes originated from mouse. At 250 ㎍/mL ethanolic extracts of P. vietnamensis, melanin contents were repressed by 64.04% compared to the control group. In addition, ethanolic extracts of P. vietnamensis downregulated tyrosinase activity and expression to 53.34% and 59.39%, respectively. As shown our result, ethanolic extracts of P. vietnamensis blocks α-MSH-mediated melanogenesis and is valuable whitening ingredients in cosmetics.

• Korean Journal of Pharmacognosy
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• v.52 no.2
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• pp.99-104
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• 2021

This study was performed to elucidated the inhibitory effects of 6,8-diprenylorobol on melanin synthesis by measuring the levels of cell viability, mRNA expression, tyrosinase activity, and melanin production in the B16F10 cell line. The effects of 6,8-diprenylorobol on tyrosinase-related protein 1 (TYRP1), TYRP2, tyrosinase (TYR), and microphthalmia-associated transcription factor (MITF) mRNA expression levels and melanin content were determined. Quantitative real-time RT-PCR shows that 6,8-diprenylorobol decreases the mRNA expression levels of TYRP1, TYRP2, TYR, and MITF in B16F10 cell line, resulting in lower levels of melanin production compared to α-MSH-treated B16F10 cells. Tyrosinase activity assays reveal that 6,8-diprenylorobol decreases melanin production in B16F10 cells. These results demonstrate the whitening effects of 6,8-diprenylorobol on B16F10 cells; thus, 6,8-diprenylorobol is a potent ingredient for skin whitening. Further research is needed on the mechanism of action of 6,8-diprenylorobol. Such research will benefit not only cosmetics, but also the health food and medical industries.

• Journal of Life Science
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• v.28 no.3
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• pp.331-338
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• 2018

Melanin is a polymer substance that plays an important role in the determination of hair growth and skin color in vivo. However, melanin, which is over-produced by reactive oxygen species, is known to cause stains, freckles, and hypercholesterolemia, which are associated with aging. Previous studies have shown that polyphosphate, one of the components of Rhynchosia Nulubilis, inhibits skin aging induced by ultraviolet rays. The aim of this study is to investigate the direct effect of Rhynchosia Nulubilis ethanolic extract (RNEE) on melanin synthesis. In this study, RNEE showed no antioxidative effects on scavenging activity of DPPH radical in addition to reducing power. The cytotoxicity of RNEE was increased in a dose-dependent manner in an MTT assay. In addition, RNEE increased tyrosinase activity and melanin synthesis in DOPA-oxidation experiments. RNEE did not promote the conversion L-DOPA into melanin in live cells, but melanin production was promoted in the RNEE-treated group after H2O2 pretreatment compared to the control group in which melanin production was reduced by treatment with H2O2. In addition, RNEE increased the expression level of tyrosinase related protein-2 (TRP-2) and increased the expression level of tyrosinase related protein-1 (TRP-1) at a concentration of $16{\mu}g/ml$. In particular, it was found that RNEE increased the expression level of SOD-3, by which superoxide anion is converted to hydrogen peroxide, higher than the control and ${\alpha}$-MSH used as a positive control at a concentration of more than $16{\mu}g/ml$. The results suggest that RNEE can induce melanogenesis related to black hair.

• Mycobiology
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• v.31 no.4
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• pp.248-250
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• 2003

Kojic acid was investigated for its antifungal activity against the human pathogenic fungi including Candida albicans, Cryptococcus neoformans and Trichophyton rubrum. For C. albicans, C. neoformans and T. rubrum, the MIC(minimum inhibitory concentration) of kojic acid was 640, 80 and 160 ${\mu}g/ml$, respectively. In C. neoformans, melanin-producing yeast, kojic acid-treated nonmelanized cell was more susceptible to magainin than melanized cell, suggesting melanin give a protective function against microbial peptide.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.60-69
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• 2013

Purified melanin pigment from Klebsiella sp. GSK was characterized by thermogravimetric, differential thermal, X-ray diffraction and elemental analysis. This melanin pigment is structurally amorphous in nature. It is thermally stable up to $300^{\circ}C$ and emits a strong exothermic peak at $700^{\circ}C$. Its carbon, hydrogen and nitrogen composition is 47.9%, 6.9% and 12.0%, respectively. It was used to scavenge metal ions and free radicals. After immobilizing the pigment and using it to adsorb copper and lead ions, the metal ion adsorption capacity was evaluated by atomic absorption spectroscopy (AAS) and the identity of melanin functional groups involved in the binding of metal ions was determined by Fourier transform infrared (FT-IR) spectroscopy. Batch adsorption studies showed that 169 mg/g of copper and 280 mg/g of lead were adsorbed onto melanin-alginate beads. The metal ion adsorption capacity of the melanin-alginate beads was relatively significant compared to alginate beads. The metal ion desorption capacity of HCl was greater (81.5% and 99% for copper and lead, respectively) than that of EDTA (80% and 71% for copper and lead, respectively). The ability of the melanin pigment to scavenge free radicals was evaluated by inhibition of the oxidation of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and was shown to be about 74% and 98%, respectively, compared with standard antioxidants.

• YAKHAK HOEJI
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• v.57 no.1
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• pp.24-31
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• 2013

Although statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, have been shown to increase melanin synthesis, the exact mechanism of this action is not fully understood. In this study we investigated the possible involvement of intracellular $Ca^{2+}$ signal in the mechanism of stimulation of melanin synthesis induced by lovastatin in B16 cells. Lovastatin stimulated the production of melanin in a dose-dependent manner in the cells. Treatment with mevalonate, FPP and GGPP, precursors of cholesterol, did not significantly suppress the lovastatin-induced melanin production, suggesting that inhibition of cholesterol synthesis may not be involved in the mechanism of the action of lovastatin. In addition, lovastatin did not significantly alter the cAMP concentration and the stimulated production of melanin by lovastatin was not significantly changed by treatment with H89, a potent inhibitor of protein kinase A, which demonstrates that cAMP pathway may not be involved. However, lovastatin increased intracellular $Ca^{2+}$ concentration in a dose-related fashion. Treatment with EGTA, an extracellular $Ca^{2+}$ chelator did not significantly alter the lovastatin-induced intracellular $Ca^{2+}$ increase and melanin synthesis, whereas intracellular $Ca^{2+}$ reduction with BAPTA/AM and intracellular $Ca^{2+}$ release blockers (dantrolene and TMB-8) completely blunted these actions of lovastatin. Taken together, these results suggest that the intracellular $Ca^{2+}$ release may play an important role in the lovastatin-induced stimulation of melanin synthesis in B16 cells. These results further suggest that lovastatin may be useful for the treatment of hypopigmentation disorders, such as vitiligo.