• Natural Product Sciences
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• v.17 no.3
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• pp.198-201
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• 2011

Tyrosinase is one of the important enzymes in the mammalian melanin synthesis. In the process of melanin synthesis, tyrosine is oxidized to DOPA (3,4-dihydroxyphenylalanine), and DOPA is further oxidized to dopaquinone. Tyrosinase is an enzyme catalyzing this oxidation of tyrosine, so chemicals that inhibit the activity of tyrosinase can be used as skin whitening agents. In this study, we isolated five constituents from the 80% MeOH extract of Morus bombycis cortex by bioactivity-guided fractionation. We performed mushroom tyrosinase inhibition assay. As a result, 7,2',4'-trihydroxyflavanone (1), 2',4',2,4,-tetrahydroxychalcone (2), and oxyresveratrol (3) showed the more potent inhibitory effect compared to kojic acid, a well-known skin whitening agent with antityrosinase effect. Moracinoside M (4) and moracin M-3'-O-${\beta}$-D-glucopyranoside (5) also showed the moderate tyrosinase inhibitory activities.

• Food Science of Animal Resources
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• v.32 no.3
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• pp.308-315
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• 2012

This study was conducted to examine the effects of egg shell membrane hydrolysates (ESMH) on skin whitening, wound healing, and UV-protection. ESMH was divided into three groups by molecular weight (Fraction I: above 10 kDa of ESMH, Fraction II: 3 kDa-10 kDa of ESMH, Fraction III: below 3 kDa of ESMH). As a result, all of ESMHs showed over 90% of protein contents. The wound healing experiment using HaCaT cells showed that the fraction I was slightly superior to other fractions depending on the concentration though it was not significantly different. In the experiments of inhibition of tyrosinase and L-3,4-dihydroxyphenylalanine (L-DOPA) oxidation to verify the L-DOPA whitening effect, the whole ESMH (before fractioning) showed a similar amount of inhibition effect with arbutin (control). In the inhibition of melanin formation in B16-F1 melanoma cells, the fraction I showed a high inhibitory effect. In the experiment for protecting the skin from ultraviolet rays using HaCaT cells, all the fractions showed a higher rate of cell viability than the control. In conclusion, this study confirmed that the cosmetic effects of ESMHs such as skin whitening, wound healing, and UV-protection, which were divided depending on the molecule weight. We could confirm that the possibility of ESMHs as a material for functional cosmetics.

• Korean Journal of Acupuncture
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• v.28 no.1
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• pp.39-46
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• 2011

본 연구는 육미지황환(六味地黃丸) 약침액(藥鍼液)가 사람 피부 섬유아세포의 콜라게나제 활성 및 프로 콜라겐 합성에 미치는 영항과 티로시나제 활성에 미치는 효과를 측정하고자 실시하였다. 방법 : HS68 사람 정상 섬유아세포에 UVB 조사 후 육미지황환(六味地黃丸) 약침액(藥鍼液)가 type I procollagen 생성과 콜라게나제 효소활성에 미치는 효능과 티로시나제 효소활성에 미치는 효능을 평가하였다. 결과 : 육미지황환(六味地黃丸) 약침액(藥鍼液)은 UVB 조사된 세포의 콜라게나제 효소활성을 통계적으로 유의하게 억제하였고, 티로시나제 활성과 L-DOPA oxidation 활성 또한 통계적으로 유의하게 억제하였다. 그러나 티로시나제와 L-DOPA oxidation 억제활성의 정도는 미약하였다. 결론 : 육미지황환(六味地黃丸) 약침액(藥鍼液)의 콜라게나제 억제효능은 주름개선 약침 치료에 활용이 가능할 것으로 생각된다.

• Archives of Pharmacal Research
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• v.16 no.3
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• pp.237-243
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• 1993

These studies were performed to investigate the acting sites of ginseng total saponins (GTS) on the U-50, 488H-induced antinociception and the inhibitory effect of the development of tolerance to U-50, 488H-induced antinociception by GTS were studied. The U-50, 488H-induced antinociception was ntagonized in mice pretreated with GTS intraperitoneally, intracerebrally. These antagonisms were reversed by the pretratment iwth a serotonin precursor, 5-hydroxytrypophan (5-HTP), but not with a noradrenaline precursor, L-dihydroxyphenylalanine (L-DOPA). However, the intraplantar sites. On the other hand, GTS inhibited the development of tolerance to U-50, 488H-induced antinociception was reversed by pretreatment with 5-HTP, but not with L-DOPA. Therefore, the antagonism of U-50, 488H-induced antinociception and the inhibition of the development of tolerance to U-50, 488H-induced antinociception and the inhibition of the development of tolerance to U-50, 488H-induced antinociception by GTS are dependent on serotonegic mechanisms.

• Journal of Ginseng Research
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• v.19 no.3
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• pp.202-205
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• 1995

We have previously reported that the antagonism of U-50,488H-induced antinociception in mice pretreated with ginseng total saponins (GTS) Ivas abolished by pretreatment with a serotonin precursor, 5-hydroxytryptophan (5-HTP), but not by a noradrenaline precursor, L-dihydroxyphenylalanine (L-DOPA) in the tail flick test. In the present experiments, the effect of the same GTS on the development of tolerance to U-50,488H-induced antinociception was determined. GTS inhibited the development of tolerance to U-50,488H-induced antinociception. The inhibitory effect of GTS on the development of tolerance to U-50,488H-induced antinociception was reversed by 5-HTP, but not by L-DOPA. These findings suggest that the inhibitory effect of GTS on the development of tolerance to U-50,488H-induced antinociception is dependent on serotonergic mechanisms. Key words Ginseng total saponin, U-50,488H, tolerance, serotonin.

• YAKHAK HOEJI
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• v.41 no.4
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• pp.439-443
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• 1997

From the root bark of Broussonetia kazinoki (Moraceae) two antioxidant components were identified. Their structures were determined as kazinol A (1) and kazinol E (2) (is oprenylated flavan and isoprenylated 1,3-diphenyl propan derivatives) by comparing NMR data with those of the reported compounds from relative plants. The antioxidant activity of 1 and 2 were monitored by the method of DPPH radical scavenging activity, whose $SC_{50}$ values were $41.4{\mu}M\;and\;33.4{\mu}M$, respectively. These compounds also exhibited inhibitory activity against tyrosinase, which is the sole key enzyme for the melanin biosynthesis and play a role in conversion of tyrosine to dopa, and dopa to dopaquinone. The antioxidant effect and the suppression of melanin biosynthesis are useful for anti-aging, increasing vitality in the incidence of major degenerative diseases, and cosmetic products in relation to hyperpigmentation.

• Clean Technology
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• v.22 no.3
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• pp.175-180
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• 2016

Tyrosinases catalyze the hydroxylation of a monophenol (monophenolase activity) and the conversion of an o-diphenol to o-quinone (diphenolase activity), which are mainly involved in the modification of tyrosine residues into 3,4-dihydroxyphenyl-alanine (DOPA) and DOPA/DOPAquinone-derived intermolecular cross-linking. Previously, we obtained a slightly acidic and cold-active tyrosinase, tyrosinase-CNK, by our recombinant protein approach. The enzyme showed optimal activity at pH 6.0 and 20 ℃ with an abnormally high monophenolase/diphenolase activity ratio and still had approximately 50% activity compared with the highest activity even in ice water. Here, we investigated reaction stability of the recombinant tyrosinase-CNK as a psychrophilic enzyme. The enzyme showed remarkable thermal stability at 0 ℃ and the activity was well conserved in repeated freeze-thaw cycles. Although water-miscible organic solvent as reaction media caused the activity decrease of tyrosinase-CNK as expected, the enzyme activity was not additionally decreased with increased concentration in organic solvents such as ethanol and acetonitrile. Also, the enzyme showed high salt tolerance in chaotropic salts. It was remarkably considered that 2⁺ metal ions might inhibit the incorporation of Cu²⁺ into the active site. We expect that these results could be used to design tyrosinase-mediated enzymatic reaction at low temperature for the production of catechols through minimizing unwanted self-oxidation and enzyme inactivation.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.552-558
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• 2002

Polyphenol oxidase from Flammulina velutipes was purified and characterized. Purification of polyphenol oxidase was achieved by ammonium sulfate precipitation, Superdex G-200 gel filtration chromatography, Phenyl superose affinity chromatography, Mono-Q anion exchange chromatography and Superdex S-200 gel filtration chromatography on FPLC. After these purification steps specific activity of purified polyphenol oxidase increased to 199.1 units/mg. Polyphenol oxidase from F. velutipes was composed of a single polypeptide with molecular weight of about 40 kDa. Optimum pH and temperature for the enzyme reaction were found to be 6.0 and $25^{\circ}C$, respectively. The activity of the enzyme gradually decreased at acidic pH between 3 and 5, and the enzyme lost its activity at alkaline pH between 8 and 10. This enzyme exhibited high substrate specificity to o-diphenols. Km-values for L-DOPA and caffeic acid were found to be 3.97 mM and 1.78 mM, respectively. 2-mercaptoethanol, L-ascorbic acid, sodium bisulfite, EDTA and $Mg^{2+}$ inhibited the activity of pholyphenol oxidase and $Cu^{2+}$, $Fe^{2+}$, $Zn^{2+}$ and $Ni^{2+}$ increased enzyme activity. The activity of enzyme was well maintained at $-70^{\circ}C$ for over 4 months, and at $-20^{\circ}C$ for 1 months.

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2001.04a
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• pp.53-53
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• 2001

No Abstract. See Full-text

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.113-113
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• 2001

Dopamine, a principal neurotransmitter in the central nervous system, accounts for 90% of total catecholamines. It serves as a precursor of certain hormones, melanins, noradrenalin and adrenalin. Parkinsonian disease (PD) is characterized by selective loss of dopaminergic neurons in the substantia nigra pars compacta and a significant dimunution in the neostriatal content of dopamine and its metabolites.(omitted)