• YAKHAK HOEJI
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• v.50 no.6
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• pp.421-428
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• 2006

Water extracts, ethanol extracts, and juice of Cusuta japonica, C, australis, and C. chinensis were prepared, and their cytotoxicity, antioxidant activity and inhibitory effects on tyrosinase activitiy and melanin biosynthesis were estimated by using melanoma Clone M-3. From this study; the following conclusions were attained. Extracts of Cuscuta japonica, C. australis, and C. chinensis showed noticeable cytotoxicity except ethanol extracts from the stem of C. australis. A maximual cytotoxicity was observed with tile ethanol extract from the seed of C, australis (87.39%). While the ethanol extract from the seed of C. japonica (91.88%) showed the most pronounced inhibitory effect on melanin biosynthesis, the water extract from the stem of C. japonica (1.05%) possessed very little inhibitory effect. The most inhibitory effect on tyrosinase activity was observed with the water extract from the stem of C. australis (76.67%). Howeverr the water extract from the stem of C. japonica showed a very poor effect on the inhibition of tyrosinase activity All the preparations, except extracts from the seed of C. australis were able to remove reactive oxygen species (ROS) in a dose-dependent manner. The juice of C. japonica demonstrated the strongest activity (59.02%).

• Journal of Life Science
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• v.21 no.7
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• pp.976-984
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• 2011

Total phenolic content was the highest in 60% ethanol extracts at 21.91 mg/g, and inhibitory activity against tyrosinase of 60% ethanol extracts was higher than ethanol extracts of other concentration. The inhibitory compounds against tyrosinase from Persimmon leaves were purified using Sephadex LH-20, MCI-gel CHP-20 column chromatography with gradient elution. Two purified compounds were isolated as a result. The chemical structures of each compound were determined and identified using $^1H$-NMR and $^{13}C$-NMR, FAB-Mass. The compounds were confirmed as (+)-gallocatechin and prodelphinidin B-3. The tyrosinase inhibitory activities of purified (+)-gallocatechin and prodelphinidin B-3 were 29.5 and 40.2%, respectively. The inhibitory activities of (+)-gallocatechin and prodelphinidin B-3 against melanin biosynthesis in melanoma cell were 32.5 and 46.7%. The safety of essence with tyrosinase inhibitory compounds from persimmon leaves was also assessed by various safety profiles. First, changes in pH (4.90~4.95) and viscosity (23,000~26,000 cP) was not detected for 60 days. Essence also showed stability against temperature and light for 60 days. All these findings suggest that extracts from persimmon leaves have a great potential as a cosmetical ingredient with a potent whitening effect.

• YAKHAK HOEJI
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• v.41 no.4
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• pp.518-523
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• 1997

To isolate biologically active compounds which exhibit tyrosinase inhibition activity and ultimately express skin whitening effect, 14 oriental herbal drugs were screened in ter ms of tyrosinase inhibition. For this purpose, in vitro enzyme assay system for tyrosinase, so called Pomerantz method with some modifications has been established. Crude methanolic extracts from 14 herbal drugs were made and examined for their inhibitory activity against tyrosinase. Those extracts from Cnidii Rhizoma, Arecae Semen, Caryophylli Flos, and Ephedrae Herba showed strong inhibitory activities on mushroom tyrosinase. Therefore, crude methanolic extracts from those 4 herbal drugs were further fractionated using ether, butanol and water. respectively. The ether and n-butanol extracts from Arecae Semen and the n-butanol and water extracts from Caryophylli Flos, respectively, showed relatively strong tyrosinase inhibitory activity compared to arbutin.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1241-1248
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• 2011

Three dimensional quantitative structure-activity relationships (3D-QSARs) between new thiosemicarbazone analogues (1-31) as a substrate molecule and their inhibitory activity against tyrosinase as a receptor were performed and discussed quantitatively using CoMFA (comparative molecular field analysis) and CoMSIA (comparative molecular similarity indices analysis) methods. According to the optimized CoMSIA 2 model obtained from the above procedure, inhibitory activities were mainly dependent upon H-bond acceptor favored field (36.5%) of substrate molecules. The optimized CoMSIA 2 model, with the sensitivity of the perturbation and the prediction, produced by a progressive scrambling analysis was not dependent on chance correlation. From molecular docking studies, it is supposed that the inhibitory activation of the substrate molecules against tyrosinase (PDB code: 1WX2) would not take place via uncompetitive inhibition forming a chelate between copper atoms in the active site of tyrosinase and thiosemicarbazone moieties of the substrate molecules, but via competitive inhibition based on H-bonding.

• Ocean and Polar Research
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• v.25 no.1
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• pp.129-132
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• 2003

The crude extracts of marine algae were screened for tyrosinase-inhibitory and radical scavenging effects. Among the samples tested, Symphyocladia latiuscula and Gloiopeltis furcata were found to be the most effective in DPPH radical scavenging test while Gigatina tenella, Sargassum thunbergii, and Sargassum sp. were moderately active. For the inhibition against mushroom tyrosinase, Symphyocladia latiuscula and Sargassum confusum showed the strongest inhibition. Codium adhaerens, Corallina pilulifera, Carpopeltis cornea, Halymenia acuminata, Hizikia fuziformis, Porphyra suborbiculata, and Enteromorpha linza exhibited mild inhibitory potency.

• Archives of Pharmacal Research
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• v.27 no.11
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• pp.1132-1135
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• 2004

In order to find new tyrosinase inhibitors and the effects of prenyl residue on flavonoid molecules, eight prenylated and three synthetic vinylated flavonoids were examined on their inhibitory effect against tyrosinase activity. From the results, kuwanon C, papyriflavonol A, sanggenon D and sophoflavescenol were found to possess the considerable inhibitory activity. Especially, sanggenon D is revealed as a potent inhibitor ($IC_{50}$ =7.3$\mu$ M), compared to the reference compound, kojic acid ($IC_{50}$ =24.8 $\mu$M). However, the prenylation with isoprenyl group or the vinylation to flavonoid molecules did not enhance tyrosinase inhibitory activity.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.3
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• pp.199-205
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• 2010

The structure-activity relationships (SARs) between a series of phenyl-2,2'-methylenebis(cyclohexane-1,3-dione) analogues (1-22) as substrate molecules and their inhibitory activity against tyrosinase were studied quantitatively using molecular hologram quantitative structure-activity relationships (HQSARs). Based on the results, new compounds with the increased tyrosinase inhibitory activity were designed. In addition, statistically favored E-2 model ($q_2$ = 0.564 & $r_2$ = 0.929) was derived. It is predicted that the activity of the most potent one (P1) of compounds newly designed by the optimized HQSAR E-2 model was $Pred.pI_{50}$ = 5.48 and the predicted inhibitory activity was about 13.4 fold higher than that of the kojic acid used as standard compound.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.9
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• pp.1357-1362
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• 2013

The objective of this study was to evaluate the effects of far-infrared (FIR) irradiation on the antioxidant and tyrosinase inhibitory activities of Schizonepeta (S.) tenuifolia. After FIR irradiation of S. tenuifolia for 30 min at 70, 90, or $110^{\circ}C$, water extracts (2 g/100 mL) were prepared at $60^{\circ}C$ for 1, 3, or 5 h. Total phenol content (TPC), 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activities (RSAs), and tyrosinase inhibitory activity of the extracts were determined. TPC, antioxidant and tyrosinase inhibitory activities of the extracts increased significantly with increasing FIR irradiation temperature of S. tenuifolia. For example, irradiation at $110^{\circ}C$ for 5 h increased TPC, DPPH RSA, ABTS RSA, and tyrosinase inhibitory activity of the extract from 204.64 to $618.67{\mu}g$ gallic acid equivalents/mL, from 30.15 to 80.84%, from 24.43 to 55.33%, and from 7.05 to 33.65%, respectively, compared to the extract of untreated S. tenuifolia. These results indicate that FIR irradiation may be useful as a processing method for enhancing the quality of S. tenuifolia.

• The Korean Journal of Mycology
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• v.46 no.3
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• pp.315-323
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• 2018

The goal of this study was to isolate wild yeasts from the fields of medicinal plants and investigate its tyrosinase inhibitory activities. Wild yeasts isolated from soil in the ginseng and Korean angelica fields of Geumsan, Chungcheongnam-do, Korea were identified by comparing the nucleotide sequences of the D1/D2 domain of 26S rDNA. In total, 43 yeast strains belonging to 21 species were isolated from 50 soil samples obtained from two medicinal plant fields. From the ginseng field, six strains of Rhodotorula glutinis and four strains of Sampaiozyma ingeniosa were isolated, out of which Rhodotorula glutinis strains were dominant. In the Korean angelica field, six strains of Cyberlindnera saturnus, three strains of Piskurozyma taiwanensis, and three strains of Saitozyma podzolica were isolated, out of which Cyberlindnera saturnus strains were dominant. We prepared cell-free extracts of the isolated wild yeasts and their tyrosinase inhibitory activities were investigated. Among 43 yeast strains, cell-free extracts of Naganishia globosa G1-7 showed the highest tyrosinase inhibitory activity (28.0%).

• Fisheries and Aquatic Sciences
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• v.3 no.3_4
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• pp.195-199
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• 2000

Tyrosinase inhibitory activities of 14 kinds of seaweed, Ecklonia stolonifera, Ecklonia cava, Undaria pinnatiflda, Laminaria japonica, Sargassum fulvellum, Sargassum miyabei, Sargassum thunbergii, Porphyra yezoensis, Gracilaria verrucosa, Carpopeltis affinis, Pachymeniopsis elliptica, Gelidium amansii, Codium fragile and Ulva pertusa were determined using commercially available mushroom tyrosinase in an in vitro assay system. The $1\%$ (w/v) methanol extract from E. stolonifera showed the highest tyrosinase inhibitory activity of $79.0\%$, electron donating activity of $79.0\%$ and total phenol content of 3.75 mg/100g. Ethyl acetate-methanol-water (7 : 2 : 0.2, v/v) fraction $(0.5\%,\;w/v)$ isolated from the methanol extract showed tyrosinase inhibitory activity of $75.9 \%$, electron donating activity of $88.1 \%$ and total phenol content of 4.38 mg/100g. Tyrosinase inhibitory activity was closely associated with total phenol content (R = 0.99) and electron donating activity (R=0.99). Maximum absorption wavelength of the fraction was 218nm and that of phenolic compounds showed about a range from 210 to 220nm. The inhibition mode of the fraction was noncompetitive inhibition.