• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.16 no.1
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• pp.100-111
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• 2003

Recently many efforts were focused to understand the mechanical insights of melanogenesis to develop the agents for hyper-pigmentation and hypo-pigmentation. In the melanin biosynthetic pathway, tyrosinase is the rate limiting enzyme, and ${\alpha}$-melanocyte stimulating hormone(MSH) or cAMP-elevating agents stimulate melanogenesis and enhance the melanin synthesis and the tyrosinase activity. The author has analyzed the effects of Rhizoma Bletillae on the basal melanogenic activities of B16 mouse melanoma cells. Rhizoma Bletillae alone markedly suppressed melanin content and tyrosinase activity in a dose-dependent manner. Pretreatment of the cells with Rhizoma Bletillae. The decrease in the tyrosinase activity was paralled by a decrease in the abundance of tyrosinase protein and tyrosinase promoter activity. These results suggest that Rhizoma Bletillae inhibits melanogenesis of B16 melanoma cells via suppression of tyrosinase activity.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.27 no.1
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• pp.99-109
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• 2001

Novel glucoconjugates phenolic moiety, 3-(methoxycarbonyl)-4-(hydroxyphenyl)-$\beta$-D-glucopyranoside(4), 3-(methoxyacetyl)-4-(hydroxyphenyl)-$\beta$-D-glucopyranoside(7), 4-(hydroxyphenyl)-$\beta$-D-ribofuranoside(11), were synthesized. In order to investigate their depigmentation effect, inhibitory activity against mushroom tyrosinase and inhibitory activity of melanin synthesis in B16 melanoma cell were evaluated in vitro. Compound 11 showed 92.0$\mu\textrm{g}$/㎖ of tyrosinase inhibitory activity whereas compound 4 and 7 showed very low activity not less than 300$\mu\textrm{g}$/㎖. Inhibitory activities of melanin synthesis in B16 melanoma cell of compound 4, 7, and 11 were 8.7, 15.1, and 36.0%, respectively, at the concentration of 100$\mu\textrm{g}$/㎖. Inhibitory activity of compound 11 was much higher than that of arbutin at the same concentration.

• Natural Product Sciences
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• v.11 no.2
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• pp.89-91
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• 2005

Effect of the neolignans, honokiol (1) and magnolol (2), isolated from Magnoliae Cortex on mushroom tyrosinase activity was investigated in vitro using L-tyrosine as a substrate. Honokiol (1) inhibited tyrosinase activity significantly in a concentration-dependent manner, on the other hand, magnolol (2) did not show tyrosinase inhibitory effect. Honokiol exhibited tyrosinase inhibitory effect with $IC_{50}$ value of $67.9\;{\mu}M$, and proved to act as a non-competitive inhibitor by the analysis of Lineweaver-Burk plot.

• The Korean Journal of Food And Nutrition
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• v.27 no.5
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• pp.837-844
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• 2014

This study was carried out to analyze the differences in p-hydroxylbenzyl alcohol (HBA) content, antitumor and anti-obesity activities and tyrosinase inhibitory activity between non-fermented G. elata (NFGP) and fermented G. elata powder. The HBA content, which is an index-component of G. elata decreased from 1.58 mg/g before fermentation to 1.07, 0.32, and 0.13 mg/g after the $1^{st}$ fermentation ($1^{st}$ FGP), $2^{nd}$ fermentation ($2^{nd}$ FGP) and $3^{rd}$ fermentation ($3^{rd}$ FGP), respectively. The anti-proliferation effects on the cell lines HT29 and AGS were significantly higher for the fermented G. elata than the NFGP. The antitumor activity was also increased in a fermentation number-dependent manner. During adipocyte differentiation, the ethanol extract of the $3^{rd}$ FGP inhibited lipid accumulation in 3T3-L1 cells significantly better than NFGP and the $1^{st}$ FGP, treated at the concentration of $10{\mu}g/mL$. The tyrosinase inhibitory activity of the $2^{nd}$ FGP at $600{\mu}g/mL$ over was higher than that of kojic acid. At the concentration of $1,000{\mu}g/mL$, the tyrosinase inhibitory activity was increased in a fermentation number-dependent manner. From these results, the fermented G. elata, especially the $3^{rd}$ FGP, is expected to be good candidate for the development of functional food and agents with antitumor, anti-obesity, and tyrosinase inhibitory potential.

• Biomolecules & Therapeutics
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• v.11 no.4
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• pp.245-248
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• 2003

The purpose of this study was to evaluate tyrosinase inhibitory activity of plant extracts, especially Korean indigenous plants, for the cosmetic use of skin whitening. When 50 plant extracts were tested, the methanol extracts of Agrimonia pilosa, Aster scaber; Dianthus sinensis, Fatsia japonica, Hemistepta lyrata, Lespedeza cuneata, Osmunda japonicum, Pyrvla japvnica, Rodgersia phodophylla and Veratrum grandiforum possessed the considerable tyrosinase inhibitory activity at 3-300 $\mu\textrm{g}$/mL. Especially, L. cuneata, aerial part of O. japonicum and V. gandiforum exhibited the strong inhibition (>50％ inhibition at 300 $\mu\textrm{g}$/mL). In particular, the methanol extract of V. grandiforum and its ethylacetate fraction showed potent inhibition ($IC_{50}$/=30 and 13$\mu\textrm{g}$/mL, respectively), while the reference compound, kojic acid, showed $IC_{50}$/ value of 26$\mu\textrm{g}$/mL. These plant extracts may be used as tyrosinase inhibitors in cosmetics.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.4
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• pp.383-390
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• 2014

The following conclusion was made from the 2D-QSAR model for the tyrosinase inhibitory activity according to the variation of the substituents R1 and R2 in analogues of compound 2-[(2,6-dioxocyclohexyl)methyl]cyclohexane- 1,3-dione (1-23). The best optimized 2D-QSAR model was $Obs.pI_{50}=-0.295({\pm}0.031)TDM$ $-0.120({\pm}0.014)DMZ+0.135({\pm}0.050)DMX.R_2+6.382({\pm}0.17)$, and the correlation $r^2=0.905$) of which was greater than its predictability ($q^2=0.843$). The magnitude of the effect of tyrosinase inhibitory activities was in order of TDM > $DMX.R_2{\geq}DMZ$, and it tended to increase as the hydrophobicity of substrate molecule (ClogP > 0) as well as the steric favor of substituent $R_1$ increased. The analysis of the model implies that inhibitory activity of substrate molecule will increase as $DMX.R_2$ (Dipole moment X component of $R_2$-substituent) increases, while TDM (Total Dipole Moment) and DMZ(Dipole Moment of Z-Component) decrease. As such, it is deemed feasible to conclude, that in order to increase the inhibitory effect, it would be rather desirable to replace the polar groups within the molecules with non-polar functional groups.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.26 no.1
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• pp.199-212
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• 2000

A series of novel ascorbic acid derivatives, polyethoxylated ascorbic acid (PEAA) were synthesized by coupling ascorbic acid with polyethylene glycol (PEG) of two molecular weights (MW: 350 and 550) at the C-2 or C-3 hydroxyl group (2PEAA350, 3PEAA350, 2PEAA550, 3PEAA550) to increase the stability and retain the activity, as a skin whitening agent. Their stability, scavenging activity against free radical, inhibitory activity against tyroxinase and inhibitory activity of melanin synthesis in Bl6 melanoma cell of PEAAs were evaluated in viかo and compared with those of ascorbic acid and 3-O-ethyl ascorbic acid (3OEAA), a Con stable vitamin C derivative. Among PEAAs, 2PEAA350 and 2PEAA550 tad high scaveniging activity against See radical, inhibitory activity against tyrosinase and inhibitory activity if melanogenesis but low stability, 3PEAA350 had high stability and moderate scavenging activity against free radical, infibitory activity against tyrosinase and inhibitory activity of melanogenesis. The stability, scavenging activity against free radical and inhibitory activity of melanogenesis of 3PEAA350 were higher than those of 30EAA. The most stable 3PEAA350 among PEAAs was nontoxic in various toxicological tests. These results suggest that PEAA would be a good whitening agent far enhancing stability and bioavailability.

• Journal of Life Science
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• v.23 no.7
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• pp.913-918
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• 2013

The applicability of the ultrasonic wave method to the extraction of useful components from seaweeds was investigated. Extracts from freeze-dried Ecklonia cava powder were prepared with hot water ($65^{\circ}C$), water ($24^{\circ}C$), 50% ethanol, and 100% ethanol, and ultrasonic extraction was also performed. The content of phenolic compounds and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and tyrosinase inhibitory activity of the extracts were analyzed, and differences in the data obtained by the ultrasonic extraction and the traditional extraction methods were compared. The phenolic content in the E. cava extract by ultrasonic extraction (142.80 mg/g) was approximately 14 times higher than the phenolic content in the hot water extract (10.03 mg/g). The DPPH radical scavenging and the tyrosinase inhibitory activities of the ultrasonic extract were approximately 4 times and 14 times higher than the hot water extracts, respectively. The correlation between the phenolic content and the DPPH radical scavenging activity ($R^2$=99.47) and between the phenolic content and the tyrosinase inhibitory activity ($R^2$=99.99) was very high. These results indicate that ultrasonic extraction is more suitable than traditional extraction for the extraction of useful components from E. cava.

• Archives of Pharmacal Research
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• v.26 no.7
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• pp.532-534
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• 2003

Kojic acid dimethyl ether (1), and the known kojic acid mono methyl ether (2), kojic acid (3) and phomaligol A (4) have been isolated from the organic extract of the broth of the marine-derived fungus Altenaria sp. collected from the surface of the marine green alga Ulva pertusa. The structures were assigned on the basis of comprehensive spectroscopic analyses. Each isolate was tested for its tyrosinase inhibitory activity. Kojic acid (3) was found to have significant tyrosinase inhibitory activity, but compounds 1, 2, and 4 were found to be inactive.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.3
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• pp.86-91
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• 1997

Some natural polyhydroxy aromatic compounds have inhibitory activity against tyrosinase, key enzyme for formation of melanin pigment. We examined the structure-activity relationship of the natural polyhydrowy aromatic compounds and synthesized a number of new derivetives through various methods. Skin lightening effects of these compounds were examined through inhibition of mushroom tyrosinase and inhibitory of melanogenesis on B-16 melanoma cells. These new compounds showed strong inhibitory activity against tyrosinase. Good lightening effects sue to inhibition of melanogenesis were observed from several resorcinol and pyrogallol derivatives. In toxicological tests such as skin primary irritation and sensitization, the above compounds were sufficiently safe for cosmetic use.