• Natural Product Sciences
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• v.20 no.1
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• pp.33-38
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• 2014

In recent times, the demand for edible medication for the treatment of hyperpigmentation has increased significantly. Therefore, the discovery of a stable, safe and inexpansive antimelanogenic component from natural substances, such as grains, is of particular interest. The levels and activities of some metabolites and/or enzymes can be increased. In the present study, we investigated the antimelanogenic effects of water-soluble extracts from barley (BE), malt (ME) and germinated barley (GBE) in melan-a cells. The inhibitory effects of ME and GBE on melanin production were significantly greater than that of BE. Interestingly, the content of ferulic acid, the proposed active component of barley, was also higher in ME and GBE than in BE by HPLC analysis. Western blot analysis of the expression of melanogenic enzymes in melan-a cells treated with BE, ME or GBE indicated the expression of both tyrosinase and tyrosinase-related protein 2 (TRP-2) significantly decreased after treatment with BE, ME or GBE. These results suggest that besides BE, ME and GBE also inhibit melanin production most likely through suppression of tyrosinase and TRP-2 expression. ME and GBE were more efficacious at inhibiting melanin production than BE was and may also represent potential skin-whitening agents.

• Microbiology and Biotechnology Letters
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• v.36 no.1
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• pp.72-81
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• 2008

The effect of genistein on melanin synthesis was studied using in vitro and in vivo model. Genistein inhibited melanin synthesis in cultured melan-a cells dose dependently. Tyrosinase activity was decreased by genistein treatment in melan-a cells, but genistein did not inhibit tyrosinase directly. Genistein did not affect the expression of tyrosinase in melan-a cells. Genistein inhibited the activity of ${\alpha}$-glucosidase in virtro and the glycosylation of tyrosinase in melan-a cells. The resulting unsaturated glycosylation of tyrosinase makes it unstable and disturb correct transportation. To further clarify the effect of genistein on the melanogenesis, we established UVB-induced hyperpigmentation on the shaved backs of brown guinea pigs. The animals were exposed to UVB radiation once a week for three consecutive weeks. Genistein (1 and 2%) or vehicle alone as a control were then topically applied to the hyperpigmented areas daily. Genistein showed significant lightening effect on the UVB-induced hyperpigmentation in five weeks. Depigmenting effect was prominent in 2% genistein treatment with Fontana-Masson staining. In conclusion, genistein may be a useful agent for skin whitening.

• Applied Microscopy
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• v.41 no.3
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• pp.169-177
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• 2011

To evaluate the whitening effect of Camellia sinensis water extract (CSWE), CSWE was treated to melan-a cells. Total polyphenol contents and flavonoid contents of CSWE were 102 mg/g and 87 mg/g, respectively. The electron-donating ability of CSWE revealed a dose-dependent response, showing the excellent ability of 82% at 800 ${\mu}g$/mL, and which was higher than the arbutin (48%). The CSWE significantly (p<0.001) suppressed the melanin synthesis and the development of melanocyte dendrites was inhibited in a dose-dependent manner. The CSWE significantly (p<0.001) inhibited both intra-cellular and cell-extracted tyrosinase activities. And inhibitory efficacies of CSWE on both melanin synthesis and tyrosinase activity were significantly (p<0.001) higher than the arbutin. The tyrosinase protein expression was not influenced by arbutin treatment. However, CSWE treatment significantly (p<0.001) reduced it. Both arbutin and CSWE treatment did not influence on mRNA expressions of tyrosinase, tyrosinase-related protein-1 and tyrosinase related protein-2.

• Korean Journal of Veterinary Research
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• v.59 no.4
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• pp.219-222
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• 2019

Three 8-12-year-old male cocker spaniels presented with an appendicular mass accompanied by pain, inflammation, lameness, and loss of nail in the digits of the forelimb or hindlimb. A histological examination revealed dermal masses of the digit composed of numerous neoplastic cells with marked pleomorphism and high mitosis. The neoplastic cells showed a strong invasive tendency into the epidermis and adjacent bony tissues, such as distal phalanx. Immunohistochemistry of the neoplastic cells in three masses revealed positive reactions for Melan-A. These three dogs were diagnosed as nailbed malignant melanoma in the digit based on the history, clinical signs, and histopathologic features.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.391.3-392
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• 2002

Melanin is a main pigment found in skin. hair and eyes, and tyrosinase plays an important role in the process of melanin polymer biosynthesis. Caesalpinia sappan L.(C. sappan) has been commonly used in Oriental folk medicines to promote blood circulation and as analgesic as well as remedy for thrombosis. This present study was designed to investigate the effect of ethyl acetate extract from C. sappan on melanogenesis in Melan-a cells. (omitted)

• Computational Structural Engineering
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• v.2 no.1
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• pp.55-64
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• 1989

A procedure which may be useful in dealing with problems of half plane is considered. Boundary elements are combined with nonlinear finite elements to facilitate their merits. Boundary elements for semi-infinite region are composed using the Melan's solution for half plane. Nonlinear finite elements are used to model irregularity or nonhomogeneity of elasto-plastic materials, which is usual in underground structures. In order to verify the procedure, a shallow tunnel under internal pressure is analysed using the nonlinear finite element method and combined method. It is shown that the developed procedure is accurate enough compared with other method.

• Korean Journal of Medicinal Crop Science
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• v.28 no.3
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• pp.195-199
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• 2020

Background: The inhibitory effect of Rodgersia podophylla root extract on melanin production has been reported, however, the study on the optimal extraction conditions that increase melanin inhibitory activity has not yet been performed. Methods and Results: In this study, we compared the melanin inhibitory activity of R. podophylla root extract obtained through different preprocessing and extraction methods. The melanin inhibitory activity was examined using Melan-A melanocytes. The results indicated that the inhibitory activity of R. podophylla roots collected in August was higher than that of the roots collected in May and November. Additionally, non-dried R. podophylla roots exhibited higher activity than dried roots, and the stirring extract was more active than the ultrasonic extract. Conclusions: Collection of R. podophylla root when the temperature is high, without drying, and stirring extraction are considered to be the optimal extraction conditions for increased melanin inhibitory effect.

• Toxicological Research
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• v.32 no.2
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• pp.141-147
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• 2016

We evaluated the antioxidant activity and melanogenic effects of black soybean ethanol extracts, including Rhynchosia nulubilis bean ethanol extract (RNBEE), R. nulubilis leaf ethanol extract (RNLEE), R. volubilis bean ethanol extract (RVBEE), and R. volubilis leaf ethanol extract (RVLEE). The total polyphenol contents of RNBEE, RNLEE, RVBEE, and RVLEE were 16.0, 57.7, 365.9, and 260.1 mg/g, respectively. The total flavonoid contents of RNBEE, RNLEE, RVBEE, and RVLEE were 40.4, 91.7, 84.7, and 216.5 mg/g, respectively. The electron-donating abilities of RNBEE, RNLEE, RVBEE, and RVLEE at $1,000{\mu}g/mL$ were 32.4%, 12.7%, 83.5%, and 84.5%, respectively. RNBEE, RNLEE, RVBEE, and RVLEE at $50{\mu}g/mL$ significantly increased (p < 0.01) melanin contents by 30.4%, 32.1%, 35.5%, and 37.4%, respectively, compared to that of the control. RNBEE, RNLEE, RVBEE, and RVLEE at $50{\mu}g/mL$ significantly increased (p < 0.01) intracellular tyrosinase activity by 18.4%, 21.8%, 21.5%, and 21.1%, respectively, compared to that of the control. These results demonstrated that black soybean ethanol extracts promote melanogenesis in melan-a cells. Among the black soybean ethanol extracts, R. volubilis was found to be more effective than R. nulubilis, and leaf extract was found to be more effective than bean extract. The potential mechanism underlying the hyperpigmentation effects of black soybeans is the promotion of tyrosinase activity.

• Journal of Microbiology and Biotechnology
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• v.25 no.12
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• pp.2011-2015
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• 2015

Ginsenoside Rb2 (Gin-Rb2) was purified from the fruit extract of Panax ginseng. Its chemical structure was measured by spectroscopic analysis, including HR-FAB-MS, ¹H-NMR, and IR spectroscopy. Gin-Rb2 decreased potent melanogenesis in melan-a cells, with 23.4% at 80 μM without cytotoxicity. Gin-Rb2 also decreased tyrosinase and MITF protein expression in melan-a cells. Furthermore, Gin-Rb2 presented inhibition of the body pigmentation in the zebrafish in vivo system and reduced melanin contents and tyrosinase activity. These results show that Gin-Rb2 isolated from P. ginseng may be an effective skin-whitening agent via the in vitro and in vivo systems.

• Korean Journal of Medicinal Crop Science
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• v.15 no.6
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• pp.434-436
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• 2007

In the previous study, we reported the inhibitory effects of Rodgersia podophylla root extract on tyrosinase activity and melanin production in melan-a cells. However, mechanism of the inhibitory activity and in vivo assay were not yet examined. This study performed the examination of the effects of Rodgersia podophylla root extract on protein expression and in vivo depigmenting activity using melan-a cells and brown guinea pigs. As the results of western immunoblotting analysis, treatment of Rodgersia podophylla root extract reduced tyrosinase expression rates in 10 and 100 ppm concentrations, dose dependently. Moreover, Rodgersia podophylla root extract exhibited depigmenting activity on UV-B induced hyperpigmentation in brown guinea pig skin. These results suggested that Rodgersia podophylla root extract could act as whitening agent for the skin via not only direct tyrosinase activity inhibition but also reducing of tyrosinase expression.