• Proceedings of the Korea Crystallographic Association Conference
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• 2003.05a
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• pp.18-18
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• 2003

Thioredoxin (Trx) is a small redox protein that is ubiquitously distributed from achaes to human. In diverse organisms, the protein is involved in various physiological roles by acting as electron donor and regulators of transcription and apoptosis as well as antioxidants. Sequences of Trx within various species are 27～69% identical to that of E. coli and all Trx proteins have the same overall fold, which consists of central five β strands surrounded by four α helices. The N-terminal cysteine in WCGPC motif of Trx is redox sensitive and the motif is highly conserved. Compared with general cysteine, the N-terminal cysteine has low pKa value. The result leads to increased reduction activity of protein. Recently, novel thio.edoxin-related protein (TRP14) was found from rat brain. TRP14 acts as disulfide reductase like Trx1, and its redox potential and pKa are similar to those of Trx1. However, TRP14 takes up electrons from cytosolic thioredoxin reductase (TrxR1), not from the mitochondrial thioredoxin reductase (TrxR2). Biological roles of TES14 were reported to be involved in regulating TNF-α induced signaling pathways in different manner with Trx1. In depletion experiments, depletion of TRP14 increased TNF-α induced phosphorylation and degradation of IκBα more than the depletion Trx1 did. It also facilitated activation of JNK and p38 MAP kinase induced by TNF-α. Unlike Trx1, TRP14 shows neither interaction nor interference with ASK1. Here, we determined three-dimensional crystal structure of TRP14 by MAD method at 1.8Å. The structure reveals that the conserved cis-Pro (Pro90) and active site-W-C-X-X-C motif, which may be involved in substrate recognition similar to Trx1 , are located at the beginning position of strand β4 and helix α2, respectively. The TRP14 structure also shows that surface of TRP14 in the vicinity of the active site, which is surrounded by an extended flexible loop and an additional short a helix, is different from that of Trx1. In addition, the structure exhibits that TRP14 interact with a distinct target proteins compared with Trx1 and the binding may depend mainly on hydrophobic and charge interactions. Consequently, the structure supports biological data that the TRP14 is involved in regulating TNF-α induced signaling pathways in different manner with Trx1.

• Toxicological Research
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• v.33 no.1
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• pp.55-62
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• 2017

We evaluated the antioxidant activity and anti-melanogenic effects of Oenothera laciniata methanol extract (OLME) in vitro by using melan-a cells. The total polyphenol and flavonoid content of OLME was 66.3 and 19.0 mg/g, respectively. The electron-donating ability, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging activity, and superoxide dismutase (SOD)-like activity of OLME ($500{\mu}g/mL$) were 94.5%, 95.6%, and 63.6%, respectively. OLME and arbutin treatment at $50{\mu}g/mL$ significantly decreased melanin content by 35.5% and 14.2%, respectively, compared to control (p < 0.05). OLME and arbutin treatment at $50{\mu}g/mL$ significantly inhibited intra-cellular tyrosinase activity by 22.6% and 12.6%, respectively, compared to control (p < 0.05). OLME ($50{\mu}g/mL$) significantly decreased tyrosinase, tyrosinase-related protein-1 (TRP-1), TRP-2, and microphthalmia-associated transcription factor-M (MITF-M) mRNA expression by 57.1%, 67.3%, 99.0%, and 77.0%, respectively, compared to control (p < 0.05). Arbutin ($50{\mu}g/mL$) significantly decreased tyrosinase, TRP-1, and TRP-2 mRNA expression by 24.2%, 42.9%, and 48.5%, respectively, compared to control (p < 0.05). However, arbutin ($50{\mu}g/mL$) did not affect MITF-M mRNA expression. Taken together, OLME showed a good antioxidant activity and anti-melanogenic effect in melan-a cells that was superior to that of arbutin, a well-known skin-whitening agent. The potential mechanism underlying the anti-melanogenic effect of OLME was inhibition of tyrosinase activity and down-regulation of tyrosinase, TRP-1, TRP-2, and MITF-M mRNA expression.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.4
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• pp.998-1003
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• 2007

The green marine algae, Capsosiphon fulvescens (CF) is a food supplement cultivated in south coast of Southern Korea. The purpose of this study was to investigate the mechanism of CF-induced hypopigmentation. The present study was designed to determine the effect of CF extracton melanogenesis in B16 cells, particularly its specific effects on tyrosinase and tyrosinase-related protein 2 (TRP-2). We measured melanin contents and analyzed melanosome associated protein levels using Western blot and Reverse transcription-polymerase chian reaction (RT-PCR) analysis. CF extract markedly inhibited melanin synthesis and tyrosinase activity. In addition, cellular dendricity was slightly decreased by CF extract. In further experiments, CF extract significantly reduced the protein levels of tyrosinase and TRP-2 in B16 cells. RT-PCR analysis revealed that tyrosinase and TRP-2 mRNA levels were unaffected by CF treatment. Therefore, these results suggest that hypopigmentary effect of CF was due to post-translational degradationof tyrosinase and TRP-2.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.27 no.1
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• pp.111-118
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• 2001

A novel melanogenic inhibitory compound, Phytoclear-EL1 (5,10-diacetyl-3-benzoyllathyrol) was isolated from Euphorbiae lathyridis. The effects of EL1 on culture normal human melanocytes (NHM) were assessed. EL1 reduced the melanin synthesis of NHM by 40% at a concentration of 2 $\square$g/ml without any apparent cytotoxicity. We also have found that the treatment of the cells with EL1 decreased the tyrosinase activity by 29% in situ. To elucidate the action mechanism of EL1, we investigated the changes in mRNA levels of tyrosinase, TRP-1 and TRP-2 using RT-PCR technique. AS a result, the mRNA levels of tyrosinase, TRP-1 and TRP-2 were markedly reduced by EL1 treatment. These results suggest that Phytoclear-EL1 is a novel whitening agent that is effective in human melanocytes.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.485-492
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• 2021

In this study, the whitening effect of Abelmoschus esculentus extract was investigated to confirm its applicability in cosmetics. To determine the whitening effect, the tyrosinase-inhibitory activity of Abelmoschus esculentus hot water extract (AEWE) and 70% ethanol extract (AEEE) was measured. At the final concentration of 1000 ㎍/ml, AEWE showed an inhibitory activity of 22.2% and AEEE of 32.8%. To determine the whitening effect at the cellular level, the viability of melanoma cells treated with AEWE and AEEE was evaluated using the MTT assay. At concentrations of 100 ㎍/ml or less, both AEWE- and AEEE-treated groups showed cell survival rates of >95%. Furthermore, in both AEWE- and AEEE-treated melanoma cells, the melanin content decreased in a concentration-dependent manner. The inhibitory effects of AEWE and AEEE used at 5, 10, 50, and 100 ㎍/ml on protein expression were measured by western blot, with β-actin as the positive control. At a concentration of 100 ㎍/ml, AEWE showed an inhibitory effect of 88.1%, 24.8%, 62.2%, and 42.9% on microphthalmia-associated transcription factors (MITF), tyrosinase, tyrosinase-related proteins (TRP)-1, and TRP-2 factors, respectively. At the same concentration, AEEE showed inhibitory effect of 65.3%, 58.3%, 66.2%, and 65.3% against MITF, tyrosinase, TRP-1, and TRP-2 factors, respectively. In conclusion, the whitening effects of AEWE and AEEE were verified, and their applicability as a natural ingredient in cosmetics was confirmed.

• Journal of Plant Biotechnology
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• v.2 no.2
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• pp.55-60
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• 2000

Experiments initiated 30 years ago to obtain selectable markers have led to a series of studies of Trp biosynthesis and anthranilate synthase (AS) the control enzyme using largely plant tissue cultures since they have experimental properties that can be readily exploited. Enzymological and compound feeding studies provided evidence that AS is the control point in the Trp biosynthesis branch and that altering the AS feedback control by the selection of mutants resistant to the Trp analog 5-methyl-tryptophan (5MT) can lead to the overproduction of this important amino acid. Plants regenerated from these Trp overproducing lines of most species also had high free Trp levels but Nicotiana tabaum (tobacco) plants expressed the feedback altered AS only in cultured cells and not in the regenerated plants. further tests by transient and stable expression of the cloned promoter for the naturally occurring tobacco feedback-insensitive AS, denoted ASA2, confirmed the tissue culture specific nature of the expression control. The 5MT caused by the expression of a feedback-insensitive AS from tobacco has been used to select protoplast fusion hybrids with several species since the resistance is expressed dominantly. Recently the ASA2 gene has been used successfully as a selectable marker to select transformed Astragalus sinicus and Glycine max hairy roots induced by Agrobactetium rhizogenes. These results show that the ASA2y-subunit can interact with the y-subunit of another species to form active feedback-insensitive enzyme that may be useful for selecting transformed cells. Plastid DNA transformation of tobacco has also effectively expressed ASA2 in the compartment in which Trp biosynthesis is localized in the cell.

• Journal of Physiology & Pathology in Korean Medicine
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• v.30 no.6
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• pp.432-438
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• 2016

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.

• Korean Journal of Pharmacognosy
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• v.45 no.3
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• pp.209-213
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• 2014

The anti-melanogenic substance was isolated from the root of Angelica gigas Nakai by silica gel column chromatography, preparative HPLC and TLC. As a result of the structure analysis by mass, $^1H$-NMR, and $^{13}C$-NMR spectrometry, the compound was identified as demethylsuberosin. Demethylsuberosin reduced melanin contents of B16F1 melanoma cells in a dose-dependent manner and decreased to about 74% at a concentration $5{\mu}g/ml$. Demethylsuberosin inhibited the expression in microphthalmia associated transcription factor (MITF), tyrosinase, tyrosinase related protein-1 (TRP-1), and tyrosinase related protein-2 (TRP-2) in melanocytes. These results suggest that the whitening activity of demethylsuberosin may be due to the inhibition of the melanin synthesis by down-regulation of MITF, tyrosinase, TRP-1 and TRP-2 expression. Thus, our results provide evidence that demethylsuberosin might be useful as a potential skin-whitening agent.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.15
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• pp.6385-6390
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• 2015

Background: Genetic polymorphisms in DNA repair genes may influence individual variation in DNA repair capacity, which may be associated with risk of developing cancer. For colorectal cancer the importance of mutations in mismatch repair genes has been extensively documented. Materials and Methods: In this study we focused on the Arg194Trp polymorphism of the DNA repair gene XRCC1, involved in base excision repair (BER) and its role in colorectal cancer in Kashmiri population. A case-control study was conducted including 100 cases of colorectal cancer, and 100 hospital-based age- and sex-matched healthy controls to examine the role of XRCC1 genetic polymorphisms in the context of colorectal cancer risk for the Kashmiri population. Results: Genotype analysis of XRCC1 Arg194Trp was conducted with a restriction fragment length polymorphism (RFLP) method. The overall association between the XRCC1 polymorphism and the CRC cases was found to be significant (p < 0.05) with both the heterozygous genotype (Arg/Trp) as well as homozygous variant genotype (Trp/Trp) being moderately associated with the elevated risk for CRC [OR=2.01 (95% CI=1.03-3.94) and OR=5.2(95% CI=1.42-19.5)] respectively. Conclusions: Our results suggest an increased risk for CRC in individuals with XRCC1 Arg194Trp polymorphism suggesting BER repair pathway modulates the risk of developing colorectal cancer in the Kashmiri population.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.6
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• pp.1456-1461
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• 2007

Melanogenesis is induced mainly by ultraviolet radiation of sunlight and ${\alpha}-melanocyte$-stimulating hormone (${\alpha}-MSH$) which binds to a specific G protein coupled receptor. The purpose of this study was to investigate the mechanism of melanogenesis inhibition in B16/F10 cells by methanol extract of Rubus coreanus Miquel (RCM). In the present study, ${\alpha}-MSH$ and forskolin led to a stimulation of melanin synthesis that appeared to result from an increased tyrosinase activity and melanin content. However, RCM inhibited the ${\alpha}-MSH$- and forskolin-induced melanin synthesis. In addition, RCM abolished the ${\alpha}-MSH$- and forskolin-induced cytoplasmic dendricity. Regarding protein levels of the melanogenic enzymes, the amounts of tyrosinase and tyrosinase-related protein 1 (TRP-1) were increased after incubation with α-MSH and forskolin. The treatment of RCM decreased the ${\alpha}-MSH$- and forskolin-induced expression levels of tyrosinase and TRP-1. Based on these findings, it is likely that RCM exerts its depigmenting effects in B16/F10 cells through the suppression of tyrosinase and TRP-1 expression, which are key enzymes for melanogenesis.