• The Plant Pathology Journal
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• v.17 no.4
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• pp.210-215
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• 2001

The phenotype of Rhizoctonia solani KR-13 was randomly segregated to both melanin-producing (M+) and non-producing (M-) types through successive cultures on PDA. M+type with dark melanin showed strong pathogenicity to rice and self-anastomosis. Meanwhile, M- type with white or less-melanized mycelia showed very weak pathogenicity and non-self-anastomosis. Melanin production of R. solani was affected by incubation temperature in both M+ and M- types, but not by light treatment. The application of tricyclazole, an inhibitor of fungal melanin biosynthesis, showed no controlling effect on R. solani causing rice sheath blight. Results of this study showed that melanization of mycelia of R. solani is an important pathogenicity factor in rice.

• Microbiology and Biotechnology Letters
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• v.23 no.2
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• pp.209-213
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• 1995

During the screening of inhibitors of melanin biosynthesis from microbial secondary metabolites, a fungal strain MR-93 which was capable of producing high level of an inhibitor was selected from plant leaf. Based on taxonomic studies, the fungus could be classified as a strain of Trichoderma sp.. The active compound (MR-93D) was purified from the culture broth by Diaion HP-20 column chromatography, ethylacetate extraction, Sephadex LH-20 column chromatography and HPLC. The inhibitor was identified as 4-hydroxy-8-isocyano-l-oxaspiro[4-4]cyclonon-8-en-2- one by spectroscopic methods of UV, $^{1}$H-NMR, ESIMS and IR. MR-93D showed a strong tyrosinase inhibitory activity with 0.03 $\mu$g/m of IC$_{50}$ value. It also inhibited melanin biosynthesis with 35 mm inhibition zone at 30 $\mu$g/paper disc in Streptomyces bikiniensis, a bacterium used as an indicator organism in this work.

• The Journal of Korean Medicine
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• v.26 no.3 s.63
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• pp.55-65
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• 2005

Objectives : This study was carried out for the development of medicine for vitiligo treatment and focused on the effect of Psoraleae fructus extract on melanin synthesis of B16 melanoma cells. Methods : Activity of tyrosinase playing a vital role in the synthesis and quantity of melanin, which is the final product in cultured B16 melanoma cells, the effects of Psoraleae fructus extract were measured. Results : The results indicated that Psoraleae fructus extract increased beth the amount of melanin and the activity of tyrosinase according to concentration, also supported by western blot analysis. Conclusions : The results suggest that Psoraleae fructus extract has an advantageous effect on the promotion of melanin synthesis and will contribute to the development of vitiligo treatment through further related studies.

• YAKHAK HOEJI
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• v.47 no.6
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• pp.398-403
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• 2003

To investigate the relationship between structure and biological activity of phenylpropanoids, we measured effects of phenylpropanoids on anti-oxidant and whitening activity, In DPPH radical scavenging activity, caffeic acid analogues showed the significant anti-oxidant activity. Although phenylpropanoids did not inhibit purified-tyrosinase activity, they significantly inhibited tyrosinase activity and melanin production in MSH-stimulated B16 melanoma cells. However, phenylpropanoids did not affect tyrosinase expression in MSH-stimulated B16 melanoma cells, which suggest that inhibition of MSH-induced melanin production was due to tyrosinase inhibition mediated via other signal pathways but not expression of tyrosinase. Phenylpropanoids also significantly inhibited both hyaluronidase and elastase activity, suggesting that phenylpropanoids may be used as whitening, hydration and anti-wrinkling agents. Hydroxyl residue of aromatic ring in phenylpropanoids plays an important role in anti-oxidant and whitening activity.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.641-646
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• 1995

During the screening of inhibitors of melanin biosynthesis from microbial secondary metabolites, a fungal strain MR304 which was capable of producing high level of an inhibitor was selected. Based on taxonomic studies, this fungus could be classified as Trichoderma harzianum. The active compound (MR304-1) was purified from culture broth by Diaion HP-20 column chromatography, ethylacetate extraction, Sephadex LH-20 column chromatographv and HPLC. The inhibitor was identified as 3-(1,5-dihvdroxy-3-isocyanocyclopent-(E)-3-envl)prop-2-enoate by spectroscopic methods of UV, ESIMS, $^{1}$H-NMR, $^{13}$C-NMR, NOE, HMQC and HMBC. MR304-1 showed strong mushroom tyrosinase inhibitory activity with IC$_{50}$ value of 0.25 $\mu $g/ml. It inhibited melanin biosynthesis with 15 mm inhibition zone at 30 $\mu $g/paper disc in Streptomyces bikiniensis, a bacterium used as an indicator organism in this work. It also inhibited melanin biosynthesis in B16 melanoma cells with a niinimum inhibitory concentration of 0.05 $\mu $g/ml.

• KSBB Journal
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• v.32 no.3
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• pp.187-192
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• 2017

In this study, we investigated the effect of Rumex axetosella, Sonchus oleraceus and Euphoibia jolkini extracts on tyrosinase activity and melanin production as natural products of whitening functional cosmetics. To measure the melanin production, 50, 100, $200{\mu}g/mL$ of Rumex axetosella, Sonchus oleraceus and Euphoibia jolkini extracts were treated on ${\alpha}-MSH$ treated B16F10 melanoma cells, respectively. Melanin contents in ${\alpha}-MSH$ treated B16F10 melanoma cells were decreased by 41.5, 51.11, and 61% in $200{\mu}g/mL$ treatment compared to none treatment, respectively. In addition, the intracellular tyrosinase activity was decreased after treatments with all extracts. Furthermore, $100{\mu}g/mL$ of Euphoibia jolkini extract was decreased 81.5% of melanin production in B16F10 melanoma cells. When the three extracts were compared, Euphoibia jolkini extract was considered to be the most functional material for whitening effect.

• KSBB Journal
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• v.32 no.3
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• pp.233-237
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• 2017

Melanin is one of the most important factors affecting skin color. Melanogenesis is the bioprocess of melanin production by melanocytes in the skin and hair follicles and is mediated by several enzymes, such as tyrosinase, tyrosinase related protein (TRP)-1, and TRP-2, MITF. In this study, we investigated the effect of Artemisia fukudo Makino extracts on tyrosinase activity and melanin production as natural products of whitening functional cosmetics. Melanin content in murine B16F10 melanoma cells were decreased by Artemisia fukudo Makino extracts in a dose-dependently. In addition, the inhibition of tyrosinase activity of Artemisia fukudo Makino extracts showed to decrease tyrosinase activity as the concentration of ${\alpha}-MSH$ was increased. Furthermore, western blot analysis revealed that Artemisia fukudo Makino extracts significantly downregulated the expression of tyrosinase, TRP-1 which treat of ${\alpha}-MSH-induced$ melanogenesis in murine B16F10 melanoma cells. As a result, Artemisia fukudo Makino extract showed functionalities as an effective whitening agent to inhibit melanin formation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.1
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• pp.89-94
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• 2014

Stem bark extracts of Fraxinus rhynchophylla Hance were found to contain two major bioactive components, esculetin and esculin. Esculetin substantially inhibited melanogenesis in B16F10 melanoma cells, with an $IC_{50}$ value of $2.8{\mu}M$, and reduced melanin synthesis in Melan-A cells. Moreover, esculetin suppressed melanin biosynthesis by inhibiting mushroom tyrosinase activity, with an $IC_{50}$ value of $40{\mu}M$. Taken together, these results suggest that esculetin could serve as an effective skin-lightening agent that inhibits melanin production by regulating the activity of melanogenic enzymes.

• The Korean Journal of Physiology
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• v.7 no.2
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• pp.59-66
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• 1973

It has been reported that vasopressin disperse the melanophore granule of frog skin. The author used hypophysectomized and adrenergic receptor blockaded animals in order to define the mechanism of vasopressin on the melanopore pigment of frog skin. The Rana niglomaculata which could be found in the Seoul area were used on this experiment. The amount of the following drugs were injected into the lymphatic sac of the frog; vaospressin $(0.05\;{\mu}g/g\;B.W.)$, dibenzylin $(0.05\;{\mu}g/g\;B.W.)$, and propranolol $(0.01\;{\mu}g/g\;B.W.)$. The following results were observed; 1. Vasopressin dispersed the melanin granules of melanocyte of frog skin. 2. The melanin granule dispersion activity of vasopressin was observed on the hypophysectomized frog. 3. The melanin granule dispersion was observed on the adrenergic receptor blockaded frog with dibenzylin or propranolol respectively, especially the later one was found to be more obvious. 4. The melanin granule dispersion was observed on the frog which was injected with vasopressin after alpha-receptor or beta-receptor blockade and the later one was found to be more obvious. 5. The melanin granule dispersion was more effective with the blockade of beta-receptor after the treatment with vasopressin on hypophysectomized frog.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.874-879
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• 2008

Tyrosinase is a key enzyme for melanin biosynthesis, and hyperpigmentation disorders are associated with abnormal accumulation of melanin pigments, which can be reduced by treatment with depigmenting agents. The methanol extract of Lespedeza cyrtobotrya $M_{IQ}$ showed inhibitory activity against mushroom tyrosinase. The active compound was purified from the methanol extract of L. cyrtobotrya, followed by several chromatographic methods, and identified as dalbergioidin (DBG) by spectroscopic methods. The results showed that DBG exhibited tyrosinase inhibitory activity with an $IC_{50}$ of $20\;{\mu}M$. The kinetic analysis of tyrosinase inhibition revealed that DBG acted as a noncompetitive inhibitor. In addition, DBG showed a melanin biosynthesis inhibition zone in the culture plate of Streptomyces bikiniensis that has commonly been used as an indicator organism. Furthermore, $27\;{\mu}M$ DBG decreased more than 50% of melanin contents on the pigmentation using the immortalized mouse melanocyte, melan-a cell.