• Journal of Radiation Protection and Research
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• v.33 no.3
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• pp.87-91
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• 2008

We induced the activation of melanocytes in the epidermis of C57BL/6 mice by ultraviolet B (UVB) irradiation and observed the effect of Bu-Zhong-Yi-Qi-Tang (BZYQT) on the formation, and decrease of UVB-induced epidermal melanocytes. C57BL/6 mice were irradiated by UVB $80\;mJ/cm^2$ (0.5 mW/sec) daily for 7 days, and BZYQT was intraperitoneally or topically applied pre- or post-irradiation. For the estimation of change of epidermal melanocytes, light microscopic observation with dihydroxyphenylalanine (DOPA) stain was performed. Split epidermal sheets prepared from the ear of untreated mice exhibited 11-16 melanocytes/$mm^2$, and one week after UV irradiation, the applied areas show an increased number of strongly DOPA-positive melanocytes with stout dendrites. But intraperitoneal or topical treatment with BZYQT before each irradiation interrupted UVB-induced pigmentation and resulted in a marked reduction in the number of epidermal melanocytes as compared to radiation control skin. The number and size of DOPA-positive epidermal melanocytes were also significantly decreased in intraperitoneally injected or topically applicated group after irradiation with BZYQT at 3rd and 6th weeks after irradiation. The present study suggests the BZYQT as inhibitor of UVB-induced pigmentation and depigmenting agent.

• Journal of Radiation Protection and Research
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• v.32 no.2
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• pp.59-64
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• 2007

We induced the activation of melanocytes in the epidermis of C57BL/6 mice by ultraviolet B (UVB) irradiation and observed the effect of bamboo (Phyllostachys nigra var. henenis Strapf) leaf extract (BLE) on the formation, and decrease of UVB-induced epidermal melanocytes. C57BL/6 mice were irradiated by $UVB\;80mJ/cm^2(0.5mW/sec)$ daily for 7 days, and BLE was intraperitoneally or topically applied pre-or post-irradiation. For the estimation of change of epidermal melanocytes, light microscopic observation with dihydroxyphenylalanine (DOPA) stain was performed. Split epidermal sheets prepared from the ear of untreated mice exhibited 11-16 $melanocytes/mm^2$, and one week after UV irradiation, the applied areas show an increased number of strongly DOPA-positive melanocytes with stout dendrites. But intraperitoneal or topical treatment with BLE before each irradiation interrupted UVB-induced pigmentation and resulted in a marked reduction in the number of epidermal melanocytes as compared to radiation control skin. The number and size of DOPA-positive epidermal melanocytes were also significantly decreased in intraperitoneally injected or topically applicated group after irradiation with BLE at 3rd and 6th weeks after irradiation. The results of present study indicate that BLE is likely to be useful as inhibitor of UVB-induced pigmentation and depigmenting agent.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.24 no.3
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• pp.65-72
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• 1998

In this study, we demonstrated the whitening effect of Lagenaria leucantha through the melanin biosynthesis of S bikiniensis and inhibition of melanogenesis in cultured Bl6 melanocytes. And we confirmed the whitening effect of Lagenaria leucantha through the depigmentation of gold fish in vivo. The melanogenesis of B$_{16}$ melanocytes was founded to be activated dose and time dependently by the treatment of u- MSH. When the B$_{16}$ melanocytes was treated with 200nM of $\alpha$-MSH, the morphology of melanocytes was remarkably changed. The melanin content and the synthesis of tyrosinase were strikingly increased. Lagenaria ieucantha inhibited the melanin formation stimulated by $\alpha$-MSH without affection of cell viability. However, Lagenaria leucantha didn't inhibit tyrosinase activity and showed weak suppression on the synthesis of tyrosinase. These results suggest Lagenaria leucantha might inhibit melanin formation with tyrosinase independent manner. Lagenaria ieucantha also inhibition melanin biosynthesis with 18mm inhibition zone in S.bikiniensis. To evaluate the inhibitory activity of melanogenesis of Lagenaria leucantha in vivo, we examined its effect on depigmentation of gold fish. Lagenaria ieucantha remarkably reduced the size and density of melanophores in gold fish. These results suggest that Lagenaria ieucantha can be used as a whitening agent in cosmetics.ics.s.

• Journal of Pathology and Translational Medicine
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• v.52 no.6
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• pp.363-368
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• 2018

Background: Vitiligo is a chronic autoimmune disease in which the destruction of melanocytes causes white spots on the affected skin. Janus kinase (JAK) is a family of intracellular, non-receptor tyrosine kinases that transduce cytokine-mediated signals via the JAK-signal transducer and activator of transcription pathway. The aim of the present study is to explore the possible role of JAK1 in the pathogenesis of vitiligo using immunohistochemical methods. Methods: The current study was conducted in a sample of 39 patients who presented with vitiligo and 22 healthy individuals who were age and sex matched as a control group. We used immunohistochemistry to evaluate JAK1 status (intensity and distribution) and assess the percentage of residual melanocytes using human melanoma black 45 (HMB45). Results: Intense and diffuse JAK1 expression was significantly more likely to indicate vitiliginous skin compared to normal skin (p<.001). Strong and diffuse JAK1 expression was associated with short disease duration, female sex, and lower percentage of melanocytes (detected by HMB45) (p<.05). Conclusions: JAK1 may be involved in the pathogenesis of vitiligo, as indicated by intense and diffuse expression compared to control and association with lower percentage of melanocytes detected by HMB45 immunostaining.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.982-988
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• 2022

Licorice (Glycyrrhiza) has been used as preventive and therapeutic material for hyperpigmentation disorders. Previously, we isolated noble compounds including dehydroglyasperin C (DGC), dehydroglyasperin D (DGD) and isoangustone A (IAA) from licorice hexane/ethanol extracts. However, their anti-melanogenic effects and underlying molecular mechanisms are unknown. The present study compared effects of DGC, DGD and IAA on pigmentation in melan-a melanocytes and human epidermal melanocytes (HEMn). DGD exerted the most excellent anti-melanogenic effect, followed by DGC and IAA at non-cytotoxic concentrations. In addition, DGD significantly inhibited tyrosinase activity in vitro cell-free system and cell system. Western blot result showed that DGD decreased expression of microphthalmia-associated transcription factor (MITF), tyrosinase and tyrosinase-related protein-1 (TRP-1) in melan-a cells and HEMn cells. DGD induced phosphorylation of MITF, ERK and Akt signal pathway promoting MITF degradation system. However, DGD did not influence p38 and cAMP-dependent protein kinase (PKA)/CREB signal pathway in melan-a cells. These result indicated that DGD inhibited melanogenesis not only direct regulation of tyrosinase but also modulating intracellular signaling related with MITF level. Collectively, these results suggested a protective role for DGD against melanogenesis.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.3
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• pp.287-292
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• 2017

Vitiligo is an intriguing depigmentary disorder and is notoriously difficult to be treated. The ultimate goal of vitiligo treatment is to replenish the lost melanocytes by immigration from hair follicle and to restore the normal function of melanogenesis by residual melanocytes. There are two types of topical calcineurin inhibitors called tacrolimus and pimecrolimus, and are recommended as the first-line treatments in vitiligo. Although pimecrolimus is efficacious for the repigmentation of vitiligo, its intrinsic mechanisms have never been investigated in vitro. This research aimed to study the ability of pimecrolimus on stimulating melanogenesis, melanocyte migration and MITF (microphthalmia associated transcription factor) protein expression. Results showed that pimecrolimus at the dosages of 1, 10, $10^2$nM were neither mitogenic nor cytotoxic to melanocytes. The addition of pimecrolimus at 10, $10^2$ and $10^3nM$ significantly increased intracellular tyrosinase activity, which was consistent with the elevated content of melanin content at the same concentrations. The peak effect was seen at 72 h in response to $10^2$nM pimecrolimus. Results of the wound scratch assay and Transwell assays indicate that pimecrolimus is effective in facilitating melanocyte migration on a collagen IV-coated surface. In addition, MITF protein yield reached the highest by pimecrolimus at $10^2nM$. In brief, pimecrolimus enhances melanin synthesis as well as promotes migration of melanocytes directly, possibly via their effects on MITF protein expression.

• BMB Reports
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• v.41 no.11
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• pp.765-770
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• 2008

Undesirable hyperpigmentation that can arise from increased melanocyte activity may be alleviated by targeting active melanocytes for apoptosis. The role of Stathmin 1 as an important regulator of microtubule dynamics is well documented. The current study examined the potential of Stathmin 1-targeting strategies in eliminating active melanocytes. A vector to overexpress Stathmin 1 and vectors to express three distinct small hairpin RNAs to knockdown Stathmin 1 expression in normal melanocytes were produced and in cell cultures acted accordingly. Both overexpression and knockdown of Stathmin 1 led to a marked increase in melanocyte apoptosis, as indicated by the accumulation of apoptotic cells and increased levels of cleaved caspase-3. Both up- and down-regulation of Stathmin 1 expression inhibited the activity of differentiated melanocytes, as indicated by decreases in both melanin production and tyrosinase activity. Taken together, these results indicate that hyperactive melanocytes can be inhibited by altering Stathmin 1 expression.

• 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.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.4 s.34
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• pp.133-143
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• 1999

To identify inhibitory effect of Bamboo extract on melanogenesis, the effect was compared with arbutin, ascorbic acid, hydroquinone, and kojic acid on the melanin biosynthesis in B16 mouse melanoma cells and cultured human melanocytes. The cell viability of the agent was tested on cultured human melanocytes. We also examined its. free radical scavenging activity on 1,1-diphenyl-2-picrylhydrazyl(DPPH). Bamboo extract showed considerable effect against melanin production and did not reduce cell viability at the concentration tested. It also showed potent free radical scavenging activity.

• Proceedings of the SCSK Conference
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• 1999.10a
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• pp.133-143
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• 1999

To identify inhibitory effect of Bamboo extract on melanogenesis, the effect was compared with arbutin. ascorbic acid, hydroquinone, and kojic acid on the melanin biosynthesis in Bl6 mouse melailoma cells and cultured hunlan melanocytes. The cell viability of the agent was tested on cultured human melanocytes. We also examined. its free radical scavenging activity on 1,1-dipheny1-2-picrylhydrazyl (DPPH). Bamboo extract showed considerable effect against melanin production and did not reduce cell viability at the concentration tested. It also showed potent free radical scavenging activity.