• Journal of Life Science
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• v.25 no.10
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• pp.1115-1123
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• 2015

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.

• Journal of Ginseng Research
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• v.47 no.6
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• pp.714-725
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• 2023

Background: Our previous investigation indicated that the preparation of Panax ginseng Meyer (P. ginseng) inhibited melanogenesis. It comprised salicylic acid (SA), protocatechuic acid (PA), p-coumaric acid (p-CA), vanillic acid (VA), and caffeic acid (CA). In this investigation, the regulatory effects of P. ginseng phenolic acid monomers on melanin production were assessed. Methods: In vitro and in vivo impact of phenolic acid monomers were assessed. Results: SA, PA, p-CA and VA inhibited tyrosinase (TYR) to reduce melanin production, whereas CA had the opposite effects. SA, PA, p-CA and VA significantly downregulated the melanocortin 1 receptor (MC1R), cycle AMP (cAMP), protein kinase A (PKA), cycle AMP-response element-binding protein (CREB), microphthalmia-associated transcription factor (MITF) pathway, reducing mRNA and protein levels of TYR, tyrosinase-related protein 1 (TYRP1), and TYRP2. Moreover, CA treatment enhanced the cAMP, PKA, and CREB pathways to promote MITF mRNA level and phosphorylation. It also alleviated MITF protein level in α-MSH-stimulated B16F10 cells, comparable to untreated B16F10, increasing the expression of phosphorylation glycogen synthase kinase 3β (p-GSK3β), β-catenin, p-ERK/ERK, and p-p38/p38. Furthermore, the GSK3β inhibitor promoted p-GSK3β and p-MITF expression, as observed in CA-treated cells. Moreover, p38 and ERK inhibitors inhibited CA-stimulated p-p38/p38, p-ERK/ERK, and p-MITF increase, which had negative binding energies with MC1R, as depicted by molecular docking. Conclusion: P. ginseng roots' phenolic acid monomers can safely inhibit melanin production by bidirectionally regulating melanin synthase transcription. Furthermore, they reduced MITF expression via MC1R/cAMP/PKA signaling pathway and enhanced MITF post-translational modification via Wnt/mitogen-activated protein kinase signaling pathway.

• BMB Reports
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• v.45 no.12
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• pp.724-729
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• 2012

In this study, we evaluated the anti-melanogenesis effects of Caffeoylserotonin (CaS) in B16 melanoma cells. Treatment with CaS reduced the melanin content and tyrosinase (TYR) activity in B16 melanoma cells in a dose-dependent manner. CaS inhibited the expression of melanogenesis-related proteins, including microphthalmia-associated transcription factor (MITF), TYR, and tyrosinase-related protein-1 (TRP-1), but not TRP-2. ${\alpha}$-MSH is known to interact with melanocortin 1 receptor (MC1R) thus activating adenylyl cyclase and increasing intracellular cyclic AMP (cAMP) levels. Furthermore, cAMP activates extracellular signal-regulated kinase 2 (ERK2) via phosphorylation, which phosphorylates MITF, thereby targeting the transcription factor to proteasomes for degradation. The CaS reduced intracellular cAMP levels to unstimulated levels and activated ERK phosphorylation within 30 min. The ERK inhibitor PD98059 abrogated the suppressive effect of CaS on ${\alpha}$-MSH-induced melanogenesis. Based on this study, the inhibitory effects of CaS on melanogenesis are derived from the downregulation of MITF signaling via the inhibition of intracellular cAMP levels, as well as acceleration of ERK activation.

• YAKHAK HOEJI
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• v.51 no.5
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• pp.350-354
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• 2007

Taurine has been shown to be tissue-protective against oxidant-induced injury and is a powerful regulator of the immune system. However, there is no study on the antimelanogenic effect of taurine. In this study, we investigated the whitening effect of taurine in B16F10 mouse melanoma cells. Cell viability was measured by MTT assay. We examined melanin contents and tyrosinase activity according to time and concentration. Extracellular signal regulated kinase (ERK) is an important regulator of melanogenesis. It has been reported that activated ERK induced microphthalmia associated transcription factor (MITF) phosphorylation and its subsequent degradation and thus reduced melanin synthesis. In our B16F10 cell culture system, taurine led to decrease melanin contents by 21% at 48 hr. We then observed taurine effects on ERK-P, MITF and tyrosinase by Western blot. ERK was activated at 18 hr and 24 hr, whereas MITF reduced. We could not observe any differences in the levels of tyrosinase. These results suggested that taurine inhibited melanogenesis by ERK signal pathway via MITF degradation. We expect that taurine has potential skin whitening agents in cosmetics.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.2
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• pp.296-301
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• 2010

The purpose of this study was to investigate the mechanism of Hexane extract of Fructus Ligustri Lucidi (HFLL)-induced regulation of melanogenesis. An apparent down-regulatory effect of tyrosinase activity was observed when B16F10 cells were incubated with HFLL. Interestingly, HFLL did not inhibit the catalytic activity of cell-free tyrosinase from B16F10 cells, whereas kojic acid directly inhibited tyrosinase activity. Regarding protein levels of melanogenic enzymes, the amounts of tyrosinase and tyrosinase-related protein 1 (TRP-1) were decreased by HFLL, while the amount of tyrosinase-related protein 2 (TRP-2) slightly was reduced after incubation with HFLL. Treatment with HFLL was found to down-regulate microphthalmia-associated transcription factor (MITF). These results suggest that HFLL is an effective inhibitor of pigmentation caused by down regulation via MITF, tyrosinase, and TRP-1 expressions.

• BMB Reports
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• v.46 no.7
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• pp.364-369
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• 2013

Endothelin-1 (ET-1) plays an indispensable role in epidermal pigmentation in hyperpigmentary disorders due to a central role in melanogenesis. Nevertheless, precise mechanism involved in ET-1-induced hyperpigmentation is still undefined. Glycoprotein (transmembrane) non-metastatic melanoma protein b (GPNMB) is a key element in melanosome formation. Therefore, we speculated that GPNMB was correlated with ET-1-induced pigmentation. After culturing with ET-1, melanin synthesis was significantly up-regulated, accompanying with increased expression of GPNMB and microphthalmia-associated transcription factor (MITF). Total number of melanosomes and melanin synthesis were sharply reduced via GPNMB-siRNA transfection, indicating ET-1-induced pigmentation by GPNMB-dependent manner. Furthermore, MITF-siRNA transfection strikingly inhibited GPNMB expression and the melanogenesis, and this suppression failed to be alleviated by ET-1 stimulation. All of these results demonstrated that ET-1 can trigger melanogenesis via the MITF-regulated GPNMB pathway. Taken together, these findings will provide a new explanation of how ET-1 induces hyperpigmentation, and possibly supply a new strategy for cosmetic studies.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2007.11a
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• pp.129-139
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• 2007

Many modalities of treatment for acquired skin hyperpigmentation are available including chemical agents or physical therapies, but none are completely satisfactory. The ideal depigmenting compound should have a potent. rapid and selective bleaching effect on hyperactivated melanocytes, carry no short- or long-term side-effects and lead to a permanent removal of undesired pigment. acting at one or more steps of the pigmentation process. Depigmentation can be achieved by regulating (i) the transcription and activity of tyrosinase, tyrosinase related protein-1 (TRP-1), tyrosinase related protein-2 (TRP-2), and/or peroxidase; (ii) the uptake and distribution of melanosomes in recipient keratinocytes and (iii) melanin and melanosome degradation and turnover of pigmented keratinocytes. One of the interesting point for development of skin whitening agent is Mitf(Microphthalmia-associated transcription factor). Mitf belongs to the basic helix-loop-helix-zip family of trabscription factors and it is crucial as it regulates both melanocyte proliferation as well as melanogenesis and is the major regulator of tyrosinase and the related enzymes (TRPs), as well as many melanosome structural proteins such as pMel17. Recently, we developed MITF-down-regulating agents from natural and synthetic sources, which have anti-melanogenic effect on in vitro and in vivo. We suggested that potent MITF-down regulating agents might be used for skin whitening cosmeceuticals.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.982-988
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• 2022

Licorice (Glycyrrhiza) has been used as preventive and therapeutic material for hyperpigmentation disorders. Previously, we isolated noble compounds including dehydroglyasperin C (DGC), dehydroglyasperin D (DGD) and isoangustone A (IAA) from licorice hexane/ethanol extracts. However, their anti-melanogenic effects and underlying molecular mechanisms are unknown. The present study compared effects of DGC, DGD and IAA on pigmentation in melan-a melanocytes and human epidermal melanocytes (HEMn). DGD exerted the most excellent anti-melanogenic effect, followed by DGC and IAA at non-cytotoxic concentrations. In addition, DGD significantly inhibited tyrosinase activity in vitro cell-free system and cell system. Western blot result showed that DGD decreased expression of microphthalmia-associated transcription factor (MITF), tyrosinase and tyrosinase-related protein-1 (TRP-1) in melan-a cells and HEMn cells. DGD induced phosphorylation of MITF, ERK and Akt signal pathway promoting MITF degradation system. However, DGD did not influence p38 and cAMP-dependent protein kinase (PKA)/CREB signal pathway in melan-a cells. These result indicated that DGD inhibited melanogenesis not only direct regulation of tyrosinase but also modulating intracellular signaling related with MITF level. Collectively, these results suggested a protective role for DGD against melanogenesis.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.2
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• pp.180-188
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• 2018

Objective: The aim of this study was to investigate the effect of single nucleotide polymorphisms (SNPs) of the melanogenesis associated transcription factor (MITF) and dopachrome tautomerase (DCT) genes on plumage coloration in Asian native duck breeds. MITF encodes a protein for microphthalmia-associated transcription factor, which regulates the development and function of melanocytes for pigmentation of skin, hair, and eyes. Among the tyrosinase-related family genes, DCT is a pigment cell-specific gene that plays important roles in the melanin synthesis pathway and the expression of skin, feather, and retina color. Methods: Five Asian duck varieties (black Korean native, white Korean native, commercial Peking, Nageswari, and Bangladeshi Deshi white ducks) were investigated to examine the polymorphisms associated with plumage colors. Among previously identified SNPs, three synonymous SNPs and one indel of MITF and nine SNPs in exon regions of DCT were genotyped. The allele frequencies for SNPs of the black and white plumage color populations were estimated and Fisher's exact test was conducted to assess the association between the allele frequencies of these two populations. Results: Two synonymous SNPs (c.114T>G and c.147T>C) and a 14-bp indel (GCTGCAAAC AGATG) in intron 7 of MITF were significantly associated with the black- and white-colored breeds (p<0.001). One non-synonymous SNP [c.938A>G (p.His313Arg)] in DCT, was highly significantly associated (p<0.001) and a synonymous SNP (c.753A>G) was significantly associated (p<0.05) with black and white color plumage in the studied duck populations. Conclusion: The results of this study provide a basis for further investigations of the associations between polymorphisms and plumage color phenotypes in Asian duck breeds.

• Journal of the Korean Applied Science and Technology
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• v.38 no.3
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• pp.883-890
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• 2021

In this study, we investigated the melanogenesis inhibitory effects of Rubus crataefifolius Leaf Extract (RCLE) in B16F10 melanoma cells. We examined the effects of RCLE on the melanin contents and tyrosinase activity, as well as the protein expression levels of the melanogenic enzymes TRP-1, TRP-2, and MITF in α-MSH -stimulated B16F10 melanoma cells. RCLE effectively inhibited tyrosinase activity and melanogenesis, suppressed the phosphorylation of PKA and CREB, and expression of MIT involved in the melanogenesis pathway, and down-regulated expression of melanogenesis related proteins. These result suggest that RCLE inhibited α-MSH-stimulated melanin synthesis by suppressing MITF expression. Therefore, our study suggests that RCLE has potential as a safe treatment for excessive pigmentation or as a natural ingredient in cosmetics.