• 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.

• Korean Journal of Pharmacognosy
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• v.46 no.1
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• pp.84-92
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• 2015

Tyrosinase is a key enzyme to control the biosynthesis of melanin pigments and has two enzyme activities, namely of 1-tyrosine hydroxylase and of 1-dopa oxidase. Thus, tyrosinase is regarded as a target in skin-whitening and therapeutic intervention of local hyperpigmentation diseases. We have tested tyrosinase inhibitory activity on the water extracts of 50 species oriental medicinal plant. Among them, five medicinal plants, Linderae Radix, Clematidis Radix, Cinnamomi Cortex Spissus, Fritillariae Thunbergii Bulbus and Bulbus Fritillariae Cirrhosae were investigated strong inhibition effect. Five medicinal plants were fractionated using organic solvents (methylene chloride, ethyl acetate, n-butanol, water). Cinnamomi Cortex Spissus (ethyl acetate fraction) was investigated strong inhibition effect. Tyrosinase inhibitory activity below $IC_{50}\;40{\mu}g/ml$ is confirmed in five herbal plants that are Linderae Radix, Clematidis Radix, Cinnamomi Cortex Spissus, Fritillariae Thunbergii Bulbus and Bulbus Fritillariae Cirrhosae. Tyrosinase inhibitory levels ($IC_{50}\;{\mu}g/ml$) of each plants were 15.56, 35.02, 25.14, 15.20 and 39.77. We also investigate the effect of effective plant's fraction. in dose of $100{\mu}g/ml$, Cinnamomi Cortex Spissus (P-36) EtOAc fraction significant inhibitory effect over 50%. Clematidis Radix (P-35) and Cinnamomi Cortex Spissus (P-36) MC fraction inhibit tyrosinase each 36.60% and 43.21%. inhibitory rates of Fritillariae Thunbergii Bulbus (P-40) EtOAc and $H_2O$ fraction are 31.40% and 31.51%. Bulbus Fritillariae Cirrhosae (P-45) BuOH fraction regulate tyrosinase activity to 37.71%. We examined tyrosinase inhibitory activity of natural products and these results suggest that several herbs have potential as a new whitening material.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.12
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• pp.1679-1683
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• 2008

The objectives of this study were to determine inhibitory effect on tyrosinase activity and antioxidant activity of the methanolic extract from grape seeds and to investigate relationships between tyrosinase inhibitory activity and antioxidant activity of the extract. The 80% methanol extracts of grape seeds were fractionated subsequently with hexane, chloroform, ethyl acetate and water. The methanolic extract and fractions from grape seeds inhibited tyrosinase activity in a concentration dependent manner. The methanolic extracts showed the highest inhibitory effects on tyrosinase activity. The inhibitory effects of the ethyl acetate fraction from the methanolic extract on tyrosinase activity was higher than other fractions. The ethyl acetate fraction from methanolic extracts showed higher antioxidant activity and contained higher polyphenolic and flavonoid contents compared to other fractions. The correlation coefficients among the polyphenoilc content of methanolic extracts, ABTS radical cation scavenging activity and inhibitory effect of tyrosinase were relatively high. These results suggest that grape seeds may have potential as a depigmentation agent for cosmetics and functional food products.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.736-741
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• 2000

The abilities of petroleum ether-extracts prepared from 75 plants to inhibit tyrosinase activity were evaluated in reverse micelles composed of isooctane/AOT(100 mM)/phosphate buffer(20 mM, pH 8.0) containing tyrosinase(105.3 units/mL) and 3,4-dihydroxyphenylalanine(0.18 mM). Compared with control which has no plant extracts, garlic could completely inhibit in vitro melanogenesis by tyrosinase, and Chinese quince, sweet potato, onion, radish bud and apple did more than 60%. Lipophilic extracts of medicinal plants and herbs such as rosemary, coriander, cinnamomi ramulus, crataegii fructus, ramulus biotae folium, mume fructus, menthae herba, eucommiae cortex and clove also inhibited tyrosinase activity more than 60%. When the extraction yield of lipophilic materials was considered together with their inhibition effect on tyrosinase, it was possible to select plants of which tyrosinase inhibitors could be produced in high quantity from unit weight. Using reverse micelles, the analysis of the capacity of lipophilic materials to inhibit tyrosinase activity which was difficult up to present could be possible.

• Journal of Microbiology and Biotechnology
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• v.19 no.7
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• pp.681-684
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• 2009

This study was carried out to evaluate the inhibitory effect of Flammulina velutipes extracts on tyrosinase activity and to identify its biologically active component. The ethyl acetate and n-butanol extracts showed potent tyrosinase inhibitory activities. Subsequently, fractions of the n-butanol extract showed only a partial tyrosinase inhibitory activity. The most active compound of tyrosinase inhibitory activity was identified from the ethyl acetate extract as 1',3'-dilinolenoyl-2'-linoleoylglycerol (LnLLn) by comparing its mass, $^1H-$, and $^{13}C-NMR$spectral data with those previously reported in the literature. LnLLn showed tyrosinase inhibitory activity with an $IC_{50}$value of 16.1 ${\mu}g/ml$. These results suggest that the ethyl acetate extract of F. velutipes could be applicable for the development of a new whitening agent.

• Korean Journal of Plant Resources
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• v.34 no.6
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• pp.510-516
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• 2021

Whitening agents derived from natural sources which do not have side effects are sought after. Schizophragma hydrangeoides is an edible plant that grows wild on Jeju Island. We aimed to determine whether S. hydrangeoides extracts show anti-melanogenic activity. Here, we found that 70% ethanol extracts of S. hydrangeoides leaf suppressed α-melanocyte-stimulating hormone-induced melanogenesis in B16F10 mouse melanoma cells. This activity of anti-melanogenesis in B16F10 cells were investigated by determining melanin content and tyrosinase activity, and by performing western blotting. The 70% ethanol extract downregulated tyrosinase and tyrosinase-related protein 1. In addition, the n-hexane fraction of S. hydrangeoides leaf (HFSH) exhibited significant anti-melanogenic activity among the various solvent fractions tested without reducing the viability of B16F10 cells. Taken together, these results indicate that extracts from S. hydrangeoides leaf can influence cellular processes via modulation of tyrosinase activity. Hence, S. hydrangeoides can be used as a whitening agent in the cosmetic industry and as a therapeutic agent for treating hyperpigmentation disorders in the clinic.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.3
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• pp.82-85
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• 1997

To develop an active material for skin darkening, we examined the effect of 300 plants on tyrosinase activity and found only Caesalpinia sappan has an ability to increase tyrosinase activity highly and melanin contents in B-16 melanoma cells. A compound increasing tyrosinase activity and melanin production was isolated from Caesalpinia sappan Lignum. Brazilin was identified as a new active agent. Brazilin increases the tyrosinase activity and malanin production of B-16 melanoma cells. In conclusion, it seems that brazilin cal be used as a new sunless tanning agent.

• 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 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.

• Korean Journal of Pharmacognosy
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• v.45 no.2
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• pp.141-146
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• 2014

In this study, we investigated on antioxidative activities and tyrosinase inhibitory activities of methanol extract and its fractions from roots of Arctium lappa. The total phenolic compound and flavonoid content of the ethylacetate fraction was found to be 818.29 mg/g and 360.59 mg/g as the highest content. In the measurement of DPPH radical scavenging ability and tyrosinase inhibitory activity, the ethylacetate fraction was higher than the other fractions and the extract. In addition, comparative analysis of phenolic compounds by liquid chromatography-mass spectrometry (MS)/MS system under the multiple-reaction monitoring (MRM) with negative-ion electrospray ionization mode. The main phenolic compounds in the extract and fractions of roots from Arctium lappa were cynarin and chlorogenic acid. The main phenolic compound of the ethylacetate fraction was cynarin. n-Butanol fraction had a significantly higher chlorogenic acid content than other samples. In conclusion, DPPH radical scavenging ability and tyrosinase inhibitory activity of the cynarin-riched ethylacetate fraction showed the highest activity.