• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.3
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• pp.115-121
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• 1997

To identify inhibitors of melanogenesis, we compared the effects of 5 compounds on mushroom tyrosinase, human melanocytic tyrosinase activity and melanin content. The cytotoxicyty of the components were also tested on cultured human melanoctes. Kojic acid showed marked inhibitory effect both on mushroom and human tyrosinase activity. This action of kijic acid is stronger than that of ascorbic acid. Arbutin inhibited human tyrosinase activity of cultured melanocytes although it had slightly inhibitory effect on mushroom tyrosinase activity. Azelaic acid had no effect on human tyrosinase activity. Melanin production was inhibited significantly by kojic acid and tranexamic acid. MTT assay showed that all of the compounds were non-cytotoxic to melanocytes at the concentrations tested. These results suggest that the effect of kojic acid on cultured meanocytes involve inhibition of tyrosinase activity and melanogenesis without affection the cell number.

• YAKHAK HOEJI
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• v.45 no.5
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• pp.522-528
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• 2001

Tyrosinase plays an important role in the process of melanin biosynthesis, and it is a biochemical target enzyme for skin-whitening agents and the remedy for disturbances in pigmentation. We have screened 25 natural plant extracts for inhibitory effects against DOPA oxidase activity of tyrosinase. For the inhibitory effect against DOPA oxidase activity of tyrosinase, the recombinant human tyrosinase and the purified mushroom tyrosinase were used. Each of the dried plants extracted with methanol, and then the extracts were subjected to sequential fractionations with methylene chloride, ethyl acetate, n-butanol and water, respective The methylene chloride fractions of Angelica tenuissima, Nardostachys chinensis, Bombyx mop and Saposhnikovia divaricata, and the n-butanol fraction of Bombyx mori notably inhibited the human tyrosinase activity as well as mushroom tyrosinase activity (more than 90% inhibition). This study suggests that the above extracts have a potential as whitening agents as single ingredients or in combination with other of the extracts.

• Journal of Applied Biological Chemistry
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• v.58 no.4
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• pp.333-338
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• 2015

The objective of this study was to investigate the whitening effect of Salvia miltorrhiza Bunge water extract (SM-W) in human epidermal melanocyte (HEM). Mushroom tyrosinase inhibitory effect of SM-W was approximately 42% at $1,000{\mu}g/mL$. The HEM cellular tyrosinase and melanin synthesis inhibition activity were 26 and 25% at $5{\mu}g/mL$, respectively. Whitening related proteins and mRNAs including tyrosinase, tyrosinase related protein 1 (TRP-1) and TRP-2, and microphthalmia associated transcription factor were reduced by SM-W treatment. In addition, the cAMP expression inhibitory effect of SM-W was decreased by 41% at $5{\mu}g/mL$ concentration. These results indicated that Salvia miltorrhiza Bunge could be used to the possible utilization of functional cosmetic ingredients by confirming whitening activity related with melanin content.

• The Korea Journal of Herbology
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• v.30 no.6
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• pp.1-6
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• 2015

Objectives : Draconis Resina (DR), the resin of Daemonorops draco Bl., is used to circulate the blood and to stop bleeding. It also has been used to generate flesh including ulceration. The present study investigated the effects of DR extract on collagen metabolism in human fibroblasts and tyrosinase activity in mushroom tyrosinase.Methods : The effect of DR extract on type I procollagen production (collagen type I synthesis) and collagenase (matrix metalloproteinase-1, henceforth referred as MMP-1) activity in human normal fibroblasts cell line. Hs68 cells after ultraviolet B (UVB, 312 nm) irradiation was measured using the enzyme - linked immunosorbent assay (ELISA). The tyrosinase activity was also measured to find out the whitening effects in mushroom tyrosinase by ELISA method.Results : There was no cytotoxicity at DR extract at concentrations of 10 μg/ml, 30 μg/ml, and 100 μg/ml. DR extract significantly inhibited the increase of collagenase activity, whereas it did not show on the reduction of type I procollagen in UVB damaged Hs68 cells. DR extract did not reduce the L - DOPA oxidation. However, it significantly reduced the tyrosinase activity by DR extract at concentraions of 0.1 mg/ml, 1 mg/ml and 10 mg/ml.Conclusions : In conclusion, DR showed the anti-wrinkle and whitening effects via the inhibition of collagenase production and the tyrosinase activity. These results suggest that DR may have potential as an anti-aging ingredient in cosmetic herb markets.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.3
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• pp.528-532
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• 2011

This study was designed to investigate the collagen metabolism and tyrosinase activity of Meretrix extracts (ME). The effect of ME on type I procollagen production and collagenase activity in human normal fibroblasts HS68 after UVB (312 nm) irradiation was measured by ELISA method. The tyrosinase activity after treatment of ME was measured as well. Type I procollagen production was recovered by ME in UVB damaged HS68 cells. The increased collagenase activity after UVB damage was significantly recovered by ME. The tyrosinase activity and L-DOPA oxidation were significantly reduced as well. However, the effects on tyrosinase activity and L-DOPA oxidation were not powerful enough to be used as whitening agents. ME showed the anti-wrinkle effects and some whitening effects in vitro. These results suggest that ME may be a useful drug as an anti-wrinkle treatments.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.3
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• pp.261-269
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• 2009

To evaluate the effect of antioxidant on the cytotoxicity induced by oxidative stress of reactive oxygen species (ROS) in cultured human skin melanocytes, colorimeric assay of XTT and tyrosinase activity assay were adopted after human skin melanocytes were preincubated for 2 hours in the media containing various concentrations of superoxide dismutase (SOD) before the treatment of hydrogen peroxide. Light microscopic study was carried out in same cultures. The results of this study were as follows 1. Cell viability of human skin melanocytes was significantly decreased by 30 and $40{\mu}M$ of hydrogen peroxide($H_2O_2$), respectively. 2. XTT50 was determined at $30{\mu}M$ after human skin melanocytes were treated with $10{\sim}40{\mu}M$ of hydrogen peroxide for 6 hours. 3. The cell viability of cultured human skin melanocytes pretreated with SOD was increased than that of cultured human skin melanocytes treated with $H_2O_2$ dose-dependently. 4. In tyrosinase activity of human skin melanocytes, the cell treated with SOD showed brown stain compared with $H_2O_2$ treated cells, dark stain. 5. In light microscopy, cultured human skin melanocytes exposed to $H_2O_2$ showed morphological changes such as the decreased cell number and cytoplasmic processes, compared with control. 6. In light microscopy, cultured human skin melanocytes pretreated with SOD showed the increase of cell number and cytoplasmic processes compared with $H_2O_2-treated$ group. From these results, it is suggested that oxidative stress of ROS such as $H_2O_2$ has cytotoxicity by showing the decreased cell viability, the increased tyrosinase activity and mophological changes of the decreased cell number and cytoplasmic processes. While, antioxidant like SOD was effective in the prevention of oxidative stress-mediated cytotoxicity by the increased cell viability, decreased tyrosinase activity and the protection of degenerative morphological changes in cultured human skin melanocytes.

• Korean Journal of Plant Resources
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• v.14 no.1
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• pp.32-37
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• 2001

Mammalian tyrosinase plays an important role in the process of melanin polymer biosynthesis by catalyzing the hydroxylation of tyrosine to 3,4-dihydroxyphenylalanine(DOPA) and the oxidation of DOPA to dopaquinone. These processes are major determinant of human skin color and involved in localized hyperpigmentation. Therefore, the enzyme inhibitors have been of great concern as skin-whitening cosmetics. Methanol extracts of 174 oriental herbs were screened for the mushroom tyrosinase inhibitory activity.

• Archives of Pharmacal Research
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• v.26 no.10
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• pp.840-845
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• 2003

Temperature change is one of the major environmental factors that influence the human skin. However, the relationship between temperature and melanogenesis has received little attention. In the present study, we investigated the effects of temperature change on melanogenesis in a mouse melanocyte cell line (Mel-Ab), and primary cultured human melanocytes. We found that Mel-Ab cells cultured at low temperatures (31 and 34$^{\circ}C$) produce less melanin than cells at 37$^{\circ}C$. These results were confirmed by experiments upon human melanocytes, demonstrating that the hypopigmenting effect of low temperatures is not cell type dependent. The observed melanin production was found to be accompanied by tyrosinase activity at each temperature, indicating that tyrosinase activity is regulated by temperature. We further examined whether the incubation period at low temperatures plays an important role in the regulation of melanogenesis. Short exposures to 27$^{\circ}C$ for 1 h or 3 h did not affect tyrosinase activity or melanin synthesis, whereas long exposures to 31$^{\circ}C$ for 2 days or 6 days significantly reduced tyrosinase activity and melanin synthesis in a duration-dependent manner. Our results suggest that exposure to low temperature and the duration of this exposure are important regulators of melanogenesis.

• Food Science of Animal Resources
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• v.32 no.5
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• pp.678-684
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• 2012

The melanin pigment in human skin is a major defense mechanism against ultraviolet light to the skin, but darken skin color. Tyrosinase is mainly responsible for melanin biosynthesis (melanogenesis) in animals and enzymatic browning (melanosis) in plants. The purpose of this study was to optimize the fermented milk process for the melanin formation inhibition by using Lactobacillus plantarum M23 with tyrosinase inhibitory activity. We used 4-factor-3-level central composite design combining with response surface methodology. Yeast extract concentration (%, $X_1$), addition of grape (%, $X_2$), incubation temperature ($^{\circ}C$, $X_3$) and incubation time (h, $X_4$) was used as an independent factor, on the other hand, pH (pH, $Y_1$), overall palatability (score, $Y_2$) and tyrosinase inhibitory activity (%, $Y_3$) was used as a dependant factor. Based on the optimization for the highest tyrosinase inhibitory activity with pH 4.4, the expected data of pH, palatability and tyrosinase inhibitory activity with 14.8 h incubation at $37.1^{\circ}C$ by the addition of 0.127% of yeast extract, 2.95% of grape was 4.42, 7.06 and 86.65%, but the real data was 4.35, 6.86 and 84.05%, respectively. Based on the previous results, fermented milk using Lactobacillus plantarum M23 with the tyrosinase inhibitory activity could contribute for the whitening and antiaging of human skin.

• Biomolecules & Therapeutics
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• v.26 no.3
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• pp.282-289
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• 2018

Melanin is a pigment produced from tyrosine in melanocytes. Although melanin has a protective role against UVB radiation-induced damage, it is also associated with the development of melanoma and darker skin tone. Tyrosinase is a key enzyme in melanin synthesis, which regulates the rate-limiting step during conversion of tyrosine into DOPA and dopaquinone. To develop effective RNA interference therapeutics, we designed a melanin siRNA pool by applying multiple prediction programs to reduce human tyrosinase levels. First, 272 siRNAs passed the target accessibility evaluation using the RNAxs program. Then we selected 34 siRNA sequences with ${\Delta}G{\geq}-34.6kcal/mol$, i-Score value ${\geq}65$, and siRNA scales score ${\leq}30$. siRNAs were designed as 19-bp RNA duplexes with an asymmetric 3' overhang at the 3' end of the antisense strand. We tested if these siRNAs effectively reduced tyrosinase gene expression using qRT-PCR and found that 17 siRNA sequences were more effective than commercially available siRNA. Three siRNAs further tested showed an effective visual color change in MNT-1 human cells without cytotoxic effects, indicating these sequences are anti-melanogenic. Our study revealed that human tyrosinase siRNAs could be efficiently designed using multiple prediction algorithms.