• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.173-177
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• 1997

For the utilizing of tannins in the functional foods and natural inhibitor against browning reaction by tyrosinase in foods, inhibition effect against tyrosinase of tannins from Korean green tea was determined. Acetone extract from Korean green tea showed inhibition effect against tyrosinase. The gallocatechin compounds showed higher inhibition effect than the catechin compounds. In terms of stereo isomers, (-)-epicatechin compounds had higher inhibition effect than the (+)-catechin compounds. The monomer had higher inhibition effect than the dimer.

• KSBB Journal
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• v.16 no.2
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• pp.220-223
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• 2001

To determine the inhibition of mushroom tyrosinase activity, fresh and dried mugwort, Artemisia princeps was extracted initially with water and ethyl alcohol, and subsequently with hexane, chloroform and ethyl acetate in that order. The highest yield was obtained from the ethyl acetate (15.2%) and hexane (15.5%) fraction of the ethanolic extract of fresh and dried mugwort, respectively. For all fractions tested, the inhibition of tyrosinase activity by fresh mugwort was higher than that of dried mugwort, and the inhibition ratio of tyrosinase activity was 98.9% in the chloroform fraction and 96.7% in the hexane fraction.

• Korean Journal of Pharmacognosy
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• v.32 no.3 s.126
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• pp.175-180
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• 2001

Solvent extracts of 17 plants collected in Cheju Island were investigated for their biological properties related to cosmeceuticals such as tyrosinase and hyaluronidase inhibition and also radical scavenging effects. The chloroform fraction of Phytolacca esculenta root exhibited strong inhibition against tyrosinase activity. No fraction showed significant hyaluronidase inhibition. Some solvent extracts of plants such as Achyranthes japonica and Artemisia princeps showed considerable radical scavenging activities.

• Food Science and Preservation
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• v.9 no.4
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• pp.369-374
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• 2002

This study was performed to investigate the effects of tyrosinase inhibition, xanthine oxidase inhibition and nitrite-scavenging effects of gamma-irradiated Schizandrae Fructus extracts from different solvents. Schizandrae Fructus was extracted by hot water, ethanol, acetone and methanol, and the extracts were irradiated 10, 20 and 30 kGy with gamma rays. All extracts from Schizandrae Fructus showed inhibition effect against tyrosinase. Tyrosinase inhibition effect of Schizandrae Fructus were higher in solvent extracts than hot water extracts by irradiation. The Schizandrae Fructus extracts had a higher inhibitory effect against xanthine oxidase, and the effect was not changed by irradiation. Nitrite scavenging activity, which was measured at various pH conditions (1.2, 3.0, 6.0), was the highest in Schizandrae Fructus extracts at pH 1.2 and 3.0. Hot water extracts provided higher nitrite scavenging effect than those of the methanol, ethanol and acetone extracts. Gamma-Irradiation may not influence on biological activites of the extracts when irradiated up to 30 kGy.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.1
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• pp.110-115
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• 2012

Various unripe peach (Prunus persica L. Batsch) seeds, which were picked on late May, were subjected to 80% methanol extracts to investigate the antioxidant activities, whitening effects, and anti-wrinkle activities. The yield of 6 cultivars (Takinosawa Gold, Kawanakawase Hakuto, Madoka, Yumefuji, Nagasawa Hakuho, and Hong Bak) from unripe peaches were the highest on Yumefuji, followed by Madoka, Kawanakawase Hakuto, Takinosawa Gold, Hong Bak, and Nagasawa Hakuho (6.16%, 6.08%, 5.65%, 5.25%, 5.23%, and 5.20%). The content of the total polyphenol of seed extracts ranged from 18.33 to 27.08 mg/g. The antioxidant in vitro assays including the DPPH and ABTS radical scavenging activities were the highest with Hong Bak and Kawanakawase Hakuto. The tyrosinase inhibition activity greatly affected the Takinosawa Gold and Kawanakawase Hakuto. Compared to the elastase inhibition activity of 6 cultivars, Madoka was higher than others, while the lowest was Hong Bak. The significant correlation coefficient values were determined (more than p=0.05) between the yield, total polyphenol content, antioxidant activities, tyrosinase inhibition, and elastase inhibition activities. The results suggested that the total polyphenol content has a high positive value on the DPPH, ABTS radical scavenging activity, and tyrosinase inhibition activity. Also, the tyrosinase inhibition activity and elastase inhibition activity showed a significant correlation (r=+0.594). The ABTS inhibition activity and tyrosinase inhibition activity that is the most suitable character represented significant positive correlation (r=+0.846). This data suggested that the methanol extracts from these unripe peaches could be potential candidates for natural cosmetics.

• YAKHAK HOEJI
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• v.44 no.3
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• pp.279-282
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• 2000

The inhibition mode of S-hydroxy-2-phenylalanylaminomethyl-4-pyron ($IC_{50}=24.6{\;}{\mu}M$) on mushroom tyrosinase was investigated using L-tyrosine as a substrate. This inhibitor is the kojic acid derivative, where the C-7 hydroxyl of kojic acid was replaced by amino group and coupled to the carboxyl of L-phenylalanine. The kinetic data obtained show a competitive inhibition pattern.

• Korean Journal of Pharmacognosy
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• v.50 no.2
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• pp.112-117
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• 2019

In this study, extracts of bark from Ulmus davidiana var. japonica and its fractions were investigated the antioxidative, antibacterial and tyrosinase inhibition activity for physiological activity towards functional applications. In the measurement of DPPH radical scavenging activity, the ethyl acetate fraction showed higher radical scavenging ability than others. Moreover, in the tyrosinase inhibition assay, showed that the ethyl acetate fraction has good inhibition effects. Results of the DPPH radical scavenging and tyrosinase inhibition activity are related with the total polyphenol concentrations of ethyl acetate fraction. In antibacterial activity used to find out by utilizing the disc diffusion assay, chloroform fraction showed strong effect against Staphylococcus aureus and S. epidermidis. These results are related with the flavonoid contents of chloroform fraction. On the other hand, in the L929 cell viability measurement by MTT assay, the hexane, butanol and aqueous fraction treated at high concentration were showed cytotoxicity. But the others samples were exhibited a moderate viabilities. As a result of investigated the antioxidant and tyrosinase inhibition activity, the ethyl acetate fraction could be applicable for cosmetics related fields. And the chloroform fraction showed significant antibacterial activity against S. aureus and S. epidermidis.

• Korean Journal of Pharmacognosy
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• v.48 no.1
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• pp.46-50
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• 2017

This study was conducted to investigate the antioxidative activities and tyrosinase inhibition effects of fractions from the distilled water extract of Inonotus obliquus. Moreover, GC-MS based analysis with trimethylsilyl (TMS) derivatization was carried out for active compound in the extract of I. obliquus. In DPPH radical scavenging ability, $SC_{50}$ values of the ethyl acetate fraction was 0.393 mg/ml as a result of the most effective than other fractions. Meanwhile, aqueous fraction showed higher effect in tyrosinase inhibitoty activity. In GC-MS based analysis with TMS derivatization, 7 compounds including syringic acid, vanillic acid and protocatechuic acid were observed in ethyl acetate fraction, and oxalic acid is the main compound in aqueous fraction. As a result, it was confirmed that oxalic acid in aqueous fraction from the distilled water extract of I. obliquus was a compound showing tyrosinase inhibition effect.

• Journal of Pharmaceutical Investigation
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• v.36 no.2
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• pp.103-107
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• 2006

In order to develop hydroquinone analogues for topical delivery, a structure-activity relationship study has been performed. A series of 2-substituted hydroquinones were tested for their ability to inhibit mushroom tyrosinase, alter melanin release and exert cytotoxicity in B6-F10 melanocytes. The electronic property of the 2-substituents did not affect the tyrosinase inhibition nor melanocyte toxicity. However, lipophilicity did affect to some degree the tyrosinase inhibition. The discrepancy in the structure-activity relationship may be due to the poor aqueous solubility of select analogues. Compounds with steric bulk at the 2-position seems to be less soluble, not enabling the analogue to interact effectively with the tyrosinase enzyme. Among the analogues tested, 2-isopropyl hydroquinone seems to be the most promising candidate for topical delivery, being the least toxic analogue with moderate melanin release inhibition.