• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.135-139
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• 2003

During the screening for inhibitors of melanin biosynthesis from plant extract, Angelica polymorpha MAXIM which showed a high level of inhibition was selected. The inhibiting substances were purified form methanol extract of Angelica polymorpha MAXIM followed by silica gel column chromatography and HPLC. The inhibitors were identified as heraclenin, isosaxalin and heraclenol 3'-Me ether, by spectrescopic methods of ESI-MS, H-NMR, C-NMR, DEPT, HMQC and HMBC. These compounds did not have mushroom tyrosinase inhibitory activity, but showed a highly potent melanin biosynthesis inhibition zone in the plate culture of Streptomyces bikiniensis, a bacterium used as an indicator organism in this work. These compounds did not show any growth inhibition against S. bikiniensis at the same concentration of melanin biosynthesis test.

• YAKHAK HOEJI
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• v.43 no.4
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• pp.494-501
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• 1999

The skin whitening effects of pine needle extract, hop extract and chestnut inner shell extract were evaluated both in vitro and in B 16 mouse melanoma cell lines. Each extracts significantly inhibited tyrosinase activity, dopa auto-oxidation and melanin biosynthesis in vitro and in B 16 cell lines. In vitro, hop extract inhibited melanin biosynthesis 15 times stronger than kojic acid at $10{\;}\mu\textrm{g}/ml$ concentration. Each extracts were stronger inhibitors of melanin biosynthesis than kojic acid in B 16 mouse melanoma cell at less than $4{\;}\mu\textrm{g}/ml$ concentration. These results show that extracts fo pine needle, hop and chestnut inner shell could be developed as skin whitening component of cosmetics.

• YAKHAK HOEJI
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• v.45 no.3
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• pp.269-275
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• 2001

The inhibitory effect of extract of Atractylodis Rhizoma alba on melanin biogenesis was studied by using B16/F10 melanoma in culture. Atractylodis Rhizoma alba significantly inhibited tyrosinase activity, and melanin contents with or without $\alpha$-MSH and forskolin in vitro. Melanin contents and tyro-sinase activity have decreased in a dose-dependent manner. These results show that extract of Atractylodis Rhizoma alba could be developed as skin whitening components of cosmetics.

• Journal of Microbiology and Biotechnology
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• v.16 no.5
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• pp.667-672
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• 2006

Tyrosinase is an enzyme that catalyzes the biosynthetic pathway of melanin pigments participating in the coloring of skin, hair, and eyes, and is widely distributed in nature. The inhibitory compounds of tyrosinase have been extensively used as a cosmetic agent with a skin-whitening effect. In this paper, several plant extracts were screened using Melan-a cells for the melanin biosynthesis inhibition activity, and Idesia polycarpa was selected. A melanin biosynthesis inhibitor was isolated from I. polycarpa fruits by activity-guided fractionation, and the inhibitor was identified as 6-hydroxy-2-[[[(1-hydroxy-6-oxo-2-cyclohexenl-yl)carbonyl]oxy]methyl]phenyl$\beta$-D-glucopyranoside (idescrapin) by comparing it with reported spectral data. Idescarpin $(IC_{50}=8{\mu}g/ml)$ reduced melanin content compared with the vehicle. In addition, the inhibitory activity of idescarpin for melanin synthesis is mediated by decreasing tyrosinase protein rather than directly inhibiting the tyrosinase activity. These results suggest that idescarpin isolated from I. polycarpa fruits may be used as a skin-whitening agent.

• 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.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.382.2-382.2
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• 2002

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 and melanin biosynthesis inhibitory activities in vitro has been carried out. The MeOH extracts and/or fractions of Polygoni multiflori Radix, Dalbergiae odoriferae Lignum. Solnani nigri Herba. Polygoni cuspidati Radix. POlygoni multiflori Ramulus. Salviae Radix showed tyrosinase inhibitory effects. Four methanolic extracts also showed melanin biosynthesis inhibitory effects in B-16 melanoma cell line.

• 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.

• Fisheries and Aquatic Sciences
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• v.21 no.11
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• pp.35.1-35.7
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• 2018

Background: The aim of this study was to investigate the in vitro inhibitory effects of Fucofuroeckol-A isolated from Eisenia bicyclis against tyrosinase activity and 3-isobutyl-1-methylxanthine (IBMX)-induced melanin biosynthesis in B16F10 melanoma cells. Result: Among the ethanolic (EtOH) extract of E. bicyclis and its organic solvent fractions, the ethyl acetate (EtOAc) soluble fraction showed a noticeable inhibitory effect on mushroom tyrosinase with an $IC_{50}$ value of $37.6{\pm}0.1{\mu}g/mL$. Repeated column chromatography of the active EtOAc fraction resulted in the isolation of Fucofuroeckol-A. It evidenced more potent tyrosinase inhibitory effect with an $IC_{50}$ value of $11.4{\pm}1.4{\mu}M$ than arbutin ($IC_{50}=1076.6{\pm}44.3{\mu}M$), which was used as a positive control. Lineweaver-Burk plots suggest that Fucofuroeckol-A plays as a noncompetitive inhibitor against tyrosinase. Furthermore, we have evaluated the inhibitory effects of Fucofuroeckol-A on IBMX-induced melanin formation in B16F10 melanoma cells. Fucofuroeckol-A ($12.5-100{\mu}M$) exhibited a significant inhibition of melanin production in the melanoma cells. Conclusion: In the present study, we suggested that Fucofuroeckol-A might prove possibility as a novel inhibitor of melanin biosynthesis in cosmetic applications.

• The Plant Pathology Journal
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• v.16 no.3
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• pp.125-129
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• 2000

A rapid and efficient assay to determine melanin biosynthesis inhibition of Magnaporthe grisea, a causal agent of the rice blast, by chemicals was developed. Wells in 24-well plates were loaded with spore suspension of the fungus and three known melanin biosynthesis inhibitors of KC10017, tricyclazole, and carpropamid. Subsequent color changes of mycelia and culture media in the wells were observed 7 days after incubation. The wells treated with KC10017 (an inhibitor of polyketide synthesis step and/or pentaketide cyclization step) became colorless, whereas tricyclazole (an inhibitor of 1, 3, 8-trihydroxynaphthalene reductase) or carpropamid (an inhibitor of scytalone dehydratase)-treated wells exhibited red color. They did not show any inhibitory effect on fungal growth. The inhibition of reaction steps prior to 1, 3, 6, 8-tetrahydroxynaphthalene formation was easily determined by colorless medium and mycelia. However, it was impossible to distinguish between inhibition of reduction steps and inhibition of dehydration steps by colors of the cultures. It was accomplished through HPLC analysis of the melanin biosynthesis-involving pentaketide metabolites accumulated by the inhibitors. Through screening of a number of synthetic chemicals using the in vitro assay, we could find a novel chemical group of melanin biosynthesis inhibitor.

• YAKHAK HOEJI
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• v.45 no.6
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• pp.701-707
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• 2001

Melanogenesis is a physiological process resulting in the synthesis of melanin pigment. We investigated the inhibitory effect of crude polysaccharide of water extract of Artemisia iwayomgi Kitamura (AI) on melanin biosystheies in B16/F10 melanoma cells. Crude polysaccharide of water extract of Artemisia iwayomgi Kitamura significantly inhibited tyrosinase activity and melanin contents with or without $\alpha$-MSH in vivo. Melanin contents and tyrosinase activity were decreased in a dose-dependent manner,These results show that crude polysaccharide of water extract of Artemisia iwayomgi Kitamura could be developed as skin whitening components of cosmetics.