• Food Science and Preservation
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• v.7 no.1
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• pp.103-107
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• 2000

Previously , the methanolic extract of peach sees was found to have a strong tyrosinase inhibitory activity in an in vitro assay. Several phenolic compunds were isolated from the seeds by solvent fractionation , Sephadex LH-20 chromatography, and preparative HPLC , and one of them showing strong tyrosinase inhibition was identified as benzoic acid by UV, IR, $^1$H/$^1$$^3$C-NMR, and EI-MS spectrsopy. Benzoic acid (IC50= 250$\mu\textrm{g}$/ml) and L-ascorbic acid (IC50=28$\mu\textrm{g}$/ml), well-known tyrosinase inhibitors. In particular , benzoic acid inhibited markedly the enzymatic browing (melanosis) of apple juices at low concentration of 0.01% and 0.05, comparable to that of L-ascorbic acid (P<0.05). these results suggest that benzoic acid, one of an effective food preservatives, may be potentially useful as a functional alternative to sulfites for the control of melanosis in fruit juices.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2375-2378
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• 2010

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3647-3650
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• 2014

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.267.2-267.2
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• 2003

Melanin biosynthesis inhibitors are useful not only for the materials used in cosmetics as skin-whitening agents but also for the remedy of hyperpigmentation. In order to find the new skin-whitening compounds from the natural products. screening of tyrosinase inhibitory activity in vitro has been carried out. The EtOH extracts of two hundred crude drugs were performed at the concentration of 500 $\mu\textrm{g}$/$m\ell$. (omitted)

• ALGAE
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• v.30 no.2
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• pp.163-170
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• 2015

Tyrosinase inhibitors are an important component of cosmetic products. Our previous studies have proposed that eckol isolated from the brown alga Ecklonia cava, can be explored as a tyrosinase inhibitor. However, cellular activities and mechanism of action of eckol remain unknown. Therefore, the current study analyzed the eckol binding modes using the crystal structure of Bacillus megaterium tyrosinase. The effects of eckol on melanin synthesis induced by ${\alpha}$-melanocyte stimulating hormone in B16F10 melanoma cells were also investigated. We predicted the 3D structure of tyrosinase and used a docking algorithm to simulate binding between tyrosinase and eckol. These molecular modeling studies were successful (calculated binding energy value, $-115.84kcal\;mol^{-1}$) and indicated that eckol interacts with Asn205, His208, and Arg209. Furthermore, eckol markedly inhibited tyrosinase activity and melanin synthesis in B16F10 melanoma cells. We also found that eckol decreased the expression of tyrosinase, tyrosinase-related protein (TRP) 1, and TRP2. These results indicate that eckol is a potent inhibitor of melanogenesis, and this finding may be useful for the development of novel pharmaceutical and cosmetic agents.

• 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.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.4
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• pp.938-944
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• 2005

Down-regulation of melanin synthesis is required for recovery of pigmentary disorders and it is known that direct inhibitors of tyrosinase suppress melanin synthesis. We screened several oriental medicinal plants using B16/Fl0 cells and found that the methanolic extract of Cnidii Rhizoma down-regulated melanin synthesis effectively. Although the proliferation of Bl6/Fl0 cells was decresed by the methanolic extract of Cnidii Rhizoma, it did not appear necrosis. Bl6/F10 cells incubated with the methanolic extract of Cnidii Rhizoma showed reduced pigmentation and tyrosinase activity. Western blotting revealed that the amount of tyrosinase was decreased by the methanolic extract of Cnidii Rhizoma. These results suggest that the inhibitary effect of the methanolic extract of Cnidii Rhizoma on melanogenesis is due to the suppression of tyrosinase in Bl6/F10 cells and Cnidii Rhizoma is a candidate for an efficient whitening agent.

• Biomolecules & Therapeutics
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• v.11 no.4
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• pp.245-248
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• 2003

The purpose of this study was to evaluate tyrosinase inhibitory activity of plant extracts, especially Korean indigenous plants, for the cosmetic use of skin whitening. When 50 plant extracts were tested, the methanol extracts of Agrimonia pilosa, Aster scaber; Dianthus sinensis, Fatsia japonica, Hemistepta lyrata, Lespedeza cuneata, Osmunda japonicum, Pyrvla japvnica, Rodgersia phodophylla and Veratrum grandiforum possessed the considerable tyrosinase inhibitory activity at 3-300 $\mu\textrm{g}$/mL. Especially, L. cuneata, aerial part of O. japonicum and V. gandiforum exhibited the strong inhibition (>50％ inhibition at 300 $\mu\textrm{g}$/mL). In particular, the methanol extract of V. grandiforum and its ethylacetate fraction showed potent inhibition ($IC_{50}$/=30 and 13$\mu\textrm{g}$/mL, respectively), while the reference compound, kojic acid, showed $IC_{50}$/ value of 26$\mu\textrm{g}$/mL. These plant extracts may be used as tyrosinase inhibitors in cosmetics.

• Archives of Pharmacal Research
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• v.22 no.3
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• pp.232-236
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• 1999

In this study, we present evidence that cotreatment of aloesin and arbutin inhibits tyrosinase activity in a synergistic manner by acting through a different action mechanism. Aloesin or arbutin similarly inhibited enzyme activity of human- and mushroom-tyrosinases with an IC50 value of 0.1 or 0.04 mM, respectively. Lineweaver-Burk plots of the enzyme kinetics data showed that aloesin inhibited tyrosinase activity noncompetitively with a Ki value of 5.3 mM, whereas arbutin did it competitively (Maeda, 1996). We then examined whether cotreatment of these agents inhibits the tyrosinase activity in a synergistic manner. The results showed that 0.01 mM aloesin in the presence of 0.03 mM arbutin inhibited activity of mushroom by 80% of the control value and the reverse was also true. The inhibitory effects were calculated to be synergistic according to the B rgi method. Taken together, we suggest that aloesin along with arbutin inhibits in synergy melanin production by combined mechanisms of noncompetitive and competitive inhibitions of tyrosinase activity.

• Journal of Life Science
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• v.27 no.2
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• pp.139-148
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• 2017

The inhibition of tyrosinase, a key enzyme in mammalian melanin synthesis, plays an important role in preventing skin pigmentation and melanoma. Therefore, tyrosinase inhibitors are very important in the fields of medicine and cosmetics. However, only a few tyrosinase inhibitors are currently available because of their toxic effects on skin or lack of selectivity and stability. Therefore, we synthesized a novel series of (E)-2-(substituted benzylidene)-2,3-dihydro-1H-cyclopenta[a]naphthalen-1-one derivatives and evaluated their inhibitory effects on mushroom tyrosinase, with the aim of discovering a novel tyrosinase inhibitor. Among 19 derivatives, MHY3655 ($IC_{50}=0.1456{\mu}M$) showed the strongest inhibitory effect on tyrosinase activity compared to kojic acid ($IC_{50}=17.2{\mu}M$), a well-known tyrosinase inhibitor. In addition, MHY3655 showed competitive inhibition on Lineweaver-Burk plots. We confirmed that MHY3655 strongly interacts with mushroom tyrosinase residues through the docking simulation. Substitutions with a hydroxy group at both R2 and R4 in the phenyl ring indicated that these groups play a major role in the high binding affinity to tyrosinase. Further, MHY3655 did not show cytotoxicity at the concentrations tested in B16F10 melanoma cells. In conclusion, the novel compound MHY3655 potentially shows tyrosinase inhibitory activity, and it could be used as an ingredient in whitening cosmetics.