• Proceedings of the PSK Conference
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• 2003.04a
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• pp.294.2-295
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• 2003

Gentisic acid, a skin-whitening agent, is known to possess tyrosinase inhibition activity. In order to develop an effective skin-whitening agent, hydroquinone derivatives in which the carboxylic acid moiety of gentisic acid was replaced with various functional groups, were selected and evaluated for their ability to inhibit tyrosinase activity as well as to inhibit melanin release. (omitted)

• Microbiology and Biotechnology Letters
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• v.49 no.2
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• pp.167-173
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• 2021

Reactive oxygen species (ROS) disrupt the cellular redox balance, exert cytotoxic effects, and consequently promote the development of various diseases in humans. Previous studies have reported that antioxidants counteract the adverse effects of ROS. Several studies examine the whitening effects of various agents based on their ability to inhibit tyrosinase activity. Tyrosinase is a critical enzyme involved in the synthesis of melanin, which protects the skin against radiation. Various agents exhibiting antioxidant and tyrosinase inhibitory activities have been synthesized. However, these synthetic drugs are associated with toxicity, decreased safety, and poor skin penetration in vivo, which has limited the clinical application of synthetic drugs. This study examined the antioxidant and tyrosinase inhibitory activities of some microalgae. The methanol, dichloromethane, and ethyl acetate extracts of four microalgal species (Tetraselmis tetrathele, Dunaliella tertiolecta, Platymonas sp., and Chaetoceros simplex) were prepared. The physiological and whitening effects of microalgal extracts were investigated by measuring the antioxidant and tyrosinase inhibitory activities. The ethyl acetate extract of D. tertiolecta exhibited the highest antioxidant and tyrosinase inhibitory activities. Future studies must focus on examining the whitening effects of microalgae on cell lines to facilitate the development of microalga-based therapeutics for skin diseases, functional health foods, and whitening agents. Thus, microalgae have potential applications in the pharmaceutical, food, and cosmetic industries.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.3
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• pp.320-326
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• 2017

This study investigated the water extracts of fallen pear (FPWE) on tyrosinase activity and melanogenesis. In the present study, we examined the effects of FPWE on mushroom tyrosinase activity in vitro, B16F10 melanoma cell tyrosinase activity, melanin contents, and expression of melanogenic enzyme proteins such as tyrosinase. An apparent down-regulatory effect on tyrosinase activity was observed when B16F10 cells were incubated with FPWE. Results of melanin assay using B16F10 cells treated with different concentrations (50, 125, and $250{\mu}g/mL$) of FPWE showed a dose-dependent decrease in melanin content. To determine whether or not FPWE indirectly affects tyrosinase activity, we assessed mushroom tyrosinase activity upon treatment with various concentrations (125, 250, 500, and $1,000{\mu}g/mL$) of FPWE. In addition, we investigated changes in the protein level of tyrosinase by using Western blotting. Tyrosinase and microphthalmia-associated transcription factor expression levels in B16F10 melanoma cells were reduced in a dose-dependent manner by FPWE. These results suggest that FPWE reduced melanin formation by inhibition of tyrosinase activity. Therefore, we suggest that FPWE could be used an effective whitening agent for skin.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.3 s.52
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• pp.265-271
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• 2005

This study is performed to investigate the effects of citrus essential oils on melanin production in B16 melanoma cells and reactive oxygen species (ROS) generation in RBL 2H3 cells. Five kinds of citrus essential oil (bergamot, grapefruit, lemmon, mandarin, petigrain) did not have any influence on DPPH radical scavenger activity, cell growth and cytotoxicity in B16 melanoma cells. In purified tyrosinase assay, both mandarin and petigrain essential oils dose-dependently inhibited its activity, but bergamot did not. In $1{\mu}M\;{\alpha}-MSH-stimulated$ B16 melanoma cells, all of 5 citrus essential oils inhibited melanin production in $\underline{a}$ dose dependent manner. On the other hand, four kinds of citrus essential oil dose-dependently increased ROS generation in RBL 2H3 mast cells, but mandarin did not. From the above results, it is possible that citrus essential oils nay be developed to be anti-melanogenic agent on the basis of their inhibitory effect on MSH-induced melanin production. Hut we can not rule out the possibility of the induction of allergy and inflammation since citrus essential oils caused ROS generation in RBL 2H3 mast cells.

• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.364-370
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• 2012

In this study, the compounds of Prunus persica Flos were extracted with 70.0% acetone and were purified using a sephadex-LH-20 column chromatography. As a result, eight fractions were isolated. For whitening effects, the tyrosinase inhibitory activity was determined to be 92.2% in Fr.-8 isolated from P. persica Flos at 1.000 ppm. The melanoma cell-originated tyrosinase inhibitory effect of Fr.-8 from P. persica Flos was approximately 63.4% at 100 ppm. The inhibitory activity on melanin synthesis by Fr.-8 isolated from P. persica Flos was about 71.7% at 100 ppm concentration. For anti-wrinkling effects, the elastase inhibition activities by Fr.-5, 7 isolated from P. persica Flos were around 71.4 and 74.5% respectively at 1,000 ppm. The collagenase inhibition activity and collagen synthesis by Fr.-8 isolated from P. persica Flos was about 80.0% at 100 ppm. All these findings suggested that the fractions of P. persica Flos have great potential as cosmeceutical ingredients with whitening and anti-wrinkling effects.

• The Korea Journal of Herbology
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• v.21 no.2
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• pp.1-7
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• 2006

Objectives : The purpose of this study is to isolate tyrosinase inhibitory material from Pinellia ternata and characterize its own structure and activity. Methods : Pinellia ternata (600g) was extracted with 95% methanol (1L) at $37^{\circ}C$ for 4 days, with shaking at 250rpm. The extract was further solvent-fractionated with n-hexane, chloroform, ethylacetate and water. The active fraction was subjected to JAI recycling prep-HPLC JAIGEL GS-320 column. The structure was identified for the active peak with NMR and GC. Results : Tyrosinase was potently inhibited by 95% methanol extracts from Pinellia ternata. The $IC_{50}$ value of the extracts was estimated to be 0.05mg/ml. The extracts was divided into four solvent-fractions, and the most potent tyrosinase inhibition was found in ethylacetate layer. $IC_{50}$ value of ethylacetate fraction was 0.001mg/ml. This fraction was further purified with JAI Recycling Preparative HPLC (Model: LC 9104). The isolated compound showing inhibitory activity was characterized on its chemical structure by NMR and the compound was identified as 3,4-dihydroxybenzaldehyde. $IC_{50}$ was found to be 7.74 ${\mu}M$ which is much lower than that of kojic acid $(66.5{\mu}M)$. Conclusions : The data suggest that 3,4-dihydroxybenzaldehyde isolated and identified from Pinellia ternata is very strong inhibitor to melanin biosynthesis.

• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.299-306
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• 2022

In this study, derivatives of trimethoxybenzene were investigated as inhibitors of melanogenesis. We examined the effects of methyl 3,4,5-trimethoxybenzoate (MTB), ethyl 3,4,5-trimethoxybenzoate (ETB), methyl 3,4,5-trimethoxycinnamate (MTC), and ethyl 3,4,5-trimethoxycinnamate (ETC). First, the inhibitory effects of these agents on melanin production were evaluated using α-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 melanoma cells. We found that all derivatives decreased α-MSH-induced melanin production in B16F10 melanoma cells; ETC showed a strong inhibitory effect at half of the concentration of the other derivatives. As tyrosinase is considered a key enzyme of melanogenesis, we also examined whether the derivatives inhibited tyrosinase activity. MTC and ETC reduced mushroom tyrosinase activity and expression levels of α-MSH-induced B16F10 cellular tyrosinase protein. Inhibitory effects of all derivatives on α-MSH-induced B16F10 cellular tyrosinase activity were shown in a dose-dependent manner. Additionally, the derivatives were exposed to diphenylpicrylhydrazyl free radical to examine their antioxidant characteristics. All derivatives showed considerable antioxidant activity, which was 2-fold higher than that of arbutin. In conclusion, the trimethoxybenzene derivatives, including MTB, ETB, MTC, and ETC exerted anti-melanogenic and antioxidant effects on α-MSH-stimulated melanogenesis, demonstrating their potential for use as novel hypopigmenting agents and antioxidants.

• Journal of Nutrition and Health
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• v.53 no.2
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• pp.121-128
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• 2020

Purpose: The Rubus coreanus fruit (RF) is an important traditional medicinal herb having antioxidant, anti-inflammatory, and immunoregulatory properties. These activities are known to change dramatically, depending on maturity of the RF. It is presumed that change of functional components, such as flavonoids, tannins, phenolic acids, triterpenoids and organic acids in RF, affect the various bioactivities. This study aimed to confirm changes in the anti-melanogenic effects of RF based on maturity, and to identify the bioactive compounds responsible. Methods: The cell viability of mature RF (MRF) and immature RF (IRF) extracts was investigated using B16F10 cells. To compare the anti-melanogenic effect of MRF and IRF extracts, we first assessed the melanin content. High-performance liquid chromatography analysis was performed to evaluate changes in the level of ellagic acid according to maturity of the RF. In addition, tyrosinase inhibitory activity of both extracts was examined. Results: MRF and IRF extracts (50-200 ㎍/mL) do not affect the cell viability of B16F10 melanoma cells. IRF extract more effectively inhibited melanin synthesis than MRF extract. The content of ellagic acid in IRF extract was higher than that obtained in MRF extract. Furthermore, greater inhibition of tyrosinase activity was observed after exposure to IRF extract than MRF extract. A positive correlation was determined between ellagic acid content and tyrosinase inhibitory activity, and a negative correlation was obtained between ellagic acid content and melanin content. Taken together, our results indicate that ellagic acid is one of the major bioactive compounds of RF that imparts a whitening effect. Conclusion: Our results indicate that ellagic acid in MRF and IRF extracts affect the anti-melanogenesis effect through inhibition of tyrosinase activity. Therefore, the ellagic acid rich IRF has greater potential for application as a natural and functional cosmetic material.

• Korean Journal of Pharmacognosy
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• v.38 no.4
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• pp.376-381
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• 2007

Seven compounds were isolated from the MeOH extract of the seeds of Plantago asiatica L. and their structures were identified as ${\beta}-sitosterol$ (1), (24R)-6${\beta}$-hydroxy-24-ethyl-cholest-4-en-3-one (2), acteoside (3), geniposidic acid (4), 1-octen-3-ol 3-O-${\beta}$-D-xylopyranosyl$(1{\rightarrow}6)-{\beta}-D-glucopyranoside$ (5), plantainoside D (6) and plantamajoside (7) on the spectroscopic analysis. Among them, $(24R)-6{\beta}$-hydroxy-24-ethyl-cholest-4-en-3-one (2) and 1-octen-3-ol 3-O-${\beta}$-D-xylopyranosyl ($1{\rightarrow}6)-{\beta}-D-glucopyranoside$ (5) were first isolated from this plant. Among them, geniposidic acid (4) showed the most potent inhibitory effect on melanogenesis, with inhibition rate of 41%.

• Journal of Life Science
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• v.23 no.12
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• pp.1428-1435
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• 2013

The aim of this study is to investigate the melanogenic effect of Oenanthe javanica ethanolic extracts (OJE) containing quercetin and kaempferol in melanoma cells (B16F1). In order to determine whether OJE inhibits melanin synthesis at the cellular level, the melanoma cells were cultured in the presence of different concentrations of OJE. In the present study, the antioxidant effects of OJE on DPPH radical scavenging, power reduction, lipid peroxidation, and DNA oxidation were evaluated in a cell free system. Furthermore, the effect of OJE on the production of melanin was determined by dopaquinone (DOPA) assay and tyrosinase activity. In addition, the protein expression of tyrosinase, as well as antioxidant enzymes such as superoxide dismutase (SOD)-1, SOD-2 and glutathione reductase (GSH), were examined using Western blot analysis. In this study, it was observed that OJE exhibited an inhibitory effect on lipid peroxidation and blocked the DNA oxidation induced by the hydroxyl radical produced by Fenton's reagent. OJE increased melanin synthesis above 50 ${\mu}g/ml$ and tyrosinase activity was detected above 50 ${\mu}g/ml$. In Western blot analysis, OJE increased the expression levels of tyrosinase, SOD-1, SOD-2, and GSH in a dose-dependent manner. These findings indicate that OJE with antioxidant activity can regulate the tyrosinase activity and melanin production in melanocyte, suggesting that it could promote the development of black hair as well as protect skin from oxidative stress.