• Applied Biological Chemistry
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• v.51 no.3
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• pp.153-158
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• 2008

An actinomycetes F-97 producing tyrosinase inhibitor was isolated from soil samples. Isolation and purification of tyrosinase inhibitor produced by F-97 was performed as follows: IRC-120 ($NH_4^+$ type) column chromatography, silica gel column chromatography, $C_{18}$ column chromatography and Sephadex LH-20 column chromatography were used successively after the centrifuged supernatant was adjusted to pH 4.0. To identify the purity of the inhibitor, octadecylsilyl(ODS) HPLC was carried out with 5% methanol as a mobile phase. Finally, the purification yield of a tyrosinase inhibitor was 5.24%. The inhibitor was very soluble in water, methanol and ethanol but insoluble in acetone, butanol, ethylacetate and chloroform. The ${\lambda}_{max}$ value of this inhibitor in water was 194nm under UV light. The biochemical test of the inhibitor was positive in Molish, Benedict, cone. $H_2SO_4$, and $KMnO_4$ tests but negative in iodine, ninhydrin, Million, Sakaguchi, xanthoproteic and Emerson tests. The tyrosinase inhibitor was stable against heat treatment of $100^{\circ}C$ for 50 minutes and pH $4{\sim}9$. The $IC_{50}$ value of this inhibitor was $19.2{\mu}g/ml$ for mushroom tyrosinase. In $1,000{\mu}g/ml$ inhibitor concentration, inhibition zone was 27 mm for Streptomyces bikiniensis NRRL B-1049. The inhibition of F-97 against mushroom tyrosinase was competitive with tyrosine.

• Journal of Life Science
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• v.17 no.6 s.86
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• pp.798-804
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• 2007

A Actinomycetes F-97 producing tyrosinase inhibitor was isolated from soil samples. The optimum culture condition for 쇼rosinase inhibitor production was investigated and the results were as follows. The best carbon source for tyrosinase inhibitor production was shown as soluble starch, the optimum concentration was 3.0%. The best nitrogen source for tyrosinase inhibitor production was shown as peptone, the optimum concentration was 0.36%. As effect of metal ions on the production of tyrosinase inhibitor, K$_2$HPO$_4$ was shown the best and the optimum concentration was 0.1 mM. The optimum pH and temperature was shown 7.0 and 30${\circ}$C, respectively. And the highest tyrosinase inhibitor production was observed at 70hr cultivation under optimum conditions in jar fermentor scale.

• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.227-233
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• 1996

Tyrosinase is an enzyme which catalyzes an enzymatic browning of some foods and in vivo synthesis of melanin. In order to produce natural and edible inhibitor of the enzyme which is expected to have whitening effect on melanogenesis, a microorganism was selected from fermented foods. It was named as NU-7, and cultured in mushroom (Lentinus edodes, Shiitake) media. Optimal media to produce tyrosinase inhibitor was formulated by varing nitrogen or carbon content. If glucose content was in a range of 3-20% and ammonium sulfate was in a range of 0-0.25%, production of inhibitor was independent of cell mass. Addition of ammonium sulfate as a nitrogen source had little effect on inhibitor production. Production of inhibitor (Y) was proportionally related to shiitake content (X) with a regression equation of Y= -0.96X$^{2}$ + 13.07X + 14.43 (R = 0.96). These results indicate that shiitake and glucose are necessary for the production of tyrosinase inhibitor. In the analysis of mycotoxin in culture broth, aflatoxin was not detected, suggesting that it would be probably edible.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.971-975
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• 2010

Eight hydroxylated stilbene derivatives including resveratrol, desoxyrhapontigenin and piceatannol as potential radical scavenger and tyrosinase inhibitor are synthesized using optimized Wittig-Horner reaction for excellent trans-selectivity in good yields. Antioxidant activity was tested against ABTS radical and tyrosinase inhibitory activity was performed with L-tyrosine as the substrate based on previous procedure with some modification. In general, catecholic stilbenes showed stronger activity against ABTS radical and resorcinolic moiety showed stronger tyrosinase inhibitory activity. Synthetic piceatannol which containing both catecholic and resorcinolic moieties showed the strongest activity in both as ABTS radical scavenger and tyrosinase inhibitor with $IC_{50}$ values of 4.1 and $8.6\;{\mu}M$, respectively.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1977-1983
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• 2006

Kaempferol was isolated and identified from the methanol extract of the flowers of Impatiens balsamina. Kaempferol showed inhibitory activity against mushroom tyrosinase with an $ID_{50}$ of 0.042 mM. Inhibition kinetics, as determined using a Lineweaver-Burk plot, showed kaempferol to be a competitive inhibitor of mushroom tyrosinase with a $K_i$ value of 0.011 mM. The lag phase of tyrosine hydroxylation catalyzed by mushroom tyrosinase clearly increased on increasing the concentration of kaempferol. In addition to its tyrosinase inhibiting activity, kaempferol strongly inhibited melanin production by Streptomyces bikiniensis, in a dose-dependent manner, without inhibiting cell growth. For comparative purposes, the tyrosinase inhibitory activity of kaempferol was also assayed versus quercetin, a positive standard.

• YAKHAK HOEJI
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• v.47 no.1
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• pp.31-36
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• 2003

To investigate the effect of protein kinase on melanin production via cAMP-dependent pathway, we measured the melanin amount and tyrosinase activity in B16 melanoma cells stimulated by alpha-melanocyte stimulating hormone (MSH), forskolin and 8-Br-cAMP. MSH, forskolin and 8-Br-cAMP significantly increased both melanin production and tyrosinase activity in B16 cells. Melanin production and tyrosinase activity by MSH are significantly inhibited by cyclic AMP-dependent protein kinase inhibitor (KT5720) and protein kinase C down-regulation treated with PMA. Bisindolmaleimide (1$\mu$M), protein kinase C inhibitor, significantly inhibited melanin production and tyrosinase activity stimulated by MSH, forskolin and 8-Br-cAMP with the following order of potency: MSH＞forskolin＞8-Br-cAMP. Tyrosine kinase inhibitor, genistein and DHC, significantly inhibited both, but the inhibitory effect was more potent in 8-Br-cAMP-stimulated B16 cells than MSH-stimulated cells. NFkB inhibitor (parthenolide) significantly inhibited melanin production and tyrosinase activity. Neither melanin production nor tyrosinase activity induced by MSH, forskolin and 8-Br-cAMP were affected by KN-62 (calmodulin-dependent protein kinase II inhibitor), PD098059 (mitogen-activated protein kinase inhibitor, MAPKK) and worthmannin (phosphatidylinositol 3-kinase inhibitor). These results suggest that both protein kinase C and tyrosine kinase are involved in melanin production by cyclic AMP-dependent pathway and NFkB pathway may play an important role in cyclic AMP-dependent melanin production in B16 melanoma cells.

• Biomolecules & Therapeutics
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• v.13 no.1
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• pp.32-34
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• 2005

Effect of isoliquiritigenin isolated from the heartwood of Dalbergia odorifera T. Chen (Leguminosae) on mushroom tyrosinase activity was investigated in vitro using L-tyrosine and L-3, 4-dihydroxyphenylalanine (L-DOPA) as the substrates. When L-tyrosine was used as a substrate, both isoliquiritigenin and kojic acid, a positive control, inhibited tyrosinase activity in a concentration-dependent manner. IC$_{50}$ values of isoliquiritigenin and kojic acid were 61.4 and 52.2 ${\muM}$, respectively. However, isoliquiritigenin showed week inhibitory effect on the oxidation of L-DOPA by tyrosinase with inhibition ratio of 9.1 ${\pm}$ 7.1% at 100 ${\muM}$. It is also suggested that 3-unsubstituted and 4-hydroxyl phenyl group in isoliquiritigenin plays an important role on the inhibition of tyrosinase activity when L-tyrosine was used as a substrate. Analysis of Lineweaver-Burk plot showed that isoliquiritigenin acts as a competitive inhibitor in case of L-tyrosine as a substrate.

• Natural Product Sciences
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• v.11 no.2
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• pp.89-91
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• 2005

Effect of the neolignans, honokiol (1) and magnolol (2), isolated from Magnoliae Cortex on mushroom tyrosinase activity was investigated in vitro using L-tyrosine as a substrate. Honokiol (1) inhibited tyrosinase activity significantly in a concentration-dependent manner, on the other hand, magnolol (2) did not show tyrosinase inhibitory effect. Honokiol exhibited tyrosinase inhibitory effect with $IC_{50}$ value of $67.9\;{\mu}M$, and proved to act as a non-competitive inhibitor by the analysis of Lineweaver-Burk plot.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.1 s.49
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• pp.25-33
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• 2005

Melanocytes synthesize melanin within discrete organelle termed melanosomes which are transferred to the surrounding keratinocytes and can be produced in varying sizes, numbers and densities. Skin whitening products have become increasingly popular in the past few years. The most successful natural skin whitening agents are: arbutin, vitamin C, kojic acid, and mulberry, which are all tyrosinase inhibitors. In this work, melanoston, a melanogenesis inhibitor isolated from yeast was studied to understand its mechanism of melanogenesis inhibition. It was found that melanoston was not a tyrosinase inhibitor, while when melanoston was applied to the B16 melanoma cell culture media, the intracellular tyrosinase activity was decreased by more than $30\%$. When B16 melanoma was stimulated with $\alpha$-MSH, cell morphololgy was dramatically changed to have lots of dendrites on the cell membrane surface. On the other hand, B16 was treated with $\alpha$-MSH and melanoston, simultaneously, the change of cell morphologv was not so great. This inhibitory effect of melanoston was found to be related to the inhibition of intracellar activation and transportation of tyrosinase, which was observed by irmmunostaining of B16 melanoma using anti-tyrosinase antibody. From these results, melanoston was regarded as an inhibitor to the differentiation of melanoma cells.

• The Journal of Natural Sciences
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• v.14 no.2
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• pp.93-102
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• 2004

A yeast strain SL-27 found to produce active intracellular tyrosinase inhibitor was screened from 972 kinds of yeasts. It was identified as Malassezia pachydermatis based on microbiological characteristics. The optimum pH and temperature for the growth of Malassezia pachydermatis SL-27 were pH 7.0 and $37^{\circ}C$, respectively. The optimal culture conditions for the production of tyrosinase inhibitor by Malassezia pachydermatis SL-27 were investigated. The optimal medium cimposition for tyrosinase inhibitor production was determined to be 1.0% casamino acid, 2.0% glucose, 0.1% $KH_2PO_4$, 0.05% $MgSo_{4-}7H20$ and each 0.01 of $CaCl_2$ and NaCl. Optimal initial pH and temperature for the production of tyrosinase inhibitor were pH 5.0 and $30^{\circ}C$, respectively. The maximum tyrosinase inhibitory activity of 84%/mL of cell-free extract was showed after 12 h of cultivation under the optimal culturing conditions.