• Journal of Life Science
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• v.33 no.2
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• pp.169-175
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• 2023

As a protective defensive mechanism against ultraviolet (UV) light exposure in skin tissue, melanocytes produce the pigment melanin. Tyrosinase plays a key role in melanin production in melanocytes. However, the overproduction of melanin can lead to lesions, such as freckles and dark spots. Thus, it is clinically important to find a modulating molecule to control melanogenesis by regulating tyrosinase expression and/or activity. It is known that catechin, a plant flavonoid, can reduce melano- genesis through the downregulation of tyrosinase expression. Here, we tested whether catechin derivatives isolated from the stem bark of Ulmus parvifolia have an effect on melanin production by regulating tyrosinase in mouse melanoma cells and in vitro mushroom tyrosinase. The catechin derivatives used in this study included C5A, C7A, C7G, and C7X. Treatments using these catechin derivatives reduced melanin production in mouse melanoma B16F10 cells in which melanogenesis was stimulated by α-MSH. Notably, the anti-melanogenic effects of catechin derivatives were similar to those of kojic acid, a well-known anti-melanogenic molecule. Both C5A and C7A directly inhibited the activity of tyrosinase isolated from mushrooms in vitro. Furthermore, our in silico computational simulation showed that these two compounds were expected to bind to the active site of tyrosinase, which is similar to kojic acid. In addition, all four catechin derivatives reduced tyrosinase protein expression. In summary, our results showed that catechin derivatives can reduce melanogenesis by regulating tyrosinase activity or expression. Thus, this study suggests that catechin derivatives isolated from U. parvifolia can be novel modulators of melanin production.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.794-798
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• 2003

The reactive oxygen species (or free radicals) generated by ultraviolet radiation cause damage on cellular components and pigment of skin. The aim of this study was to investigate the skin-whitenig effect of Okyong-san. Inhibitory effects of okyong-san extracts on melanin synthesis were studied. Namely, UV-absorbing ability, free radical scavenging activity and tyrosinase inhibitory activity of okyong-san extracts were investigated. As a result, the extracts of okyong-san were found to inhibit the activity of tyrosinase and they showed an absorbance in the UV-B region and UV-C region. We also observed that extracts of okyong-san had free radical scavenging activity.

• The Korean Journal of Cytopathology
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• v.9 no.1
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• pp.111-115
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• 1998

Although the characteristic cytologic features of melanoma have been well described the diagnosis of metastatic melanoma by fine needle aspiration cytology (FNAC) may be difficult in the case of amelanotic melanoma and in the absence of awareness of clinical history. Furthermore, when the breast is the site of initial presentation, it could simulate a primary breast carcinoma leading to misdiagnosis. The recognition of metastatic malignant melanoma in FNAC material is essential to avoid an unnecessary mastectomy and to ensure appropriate chemotherapy. We experienced a case of metastatic melanoma of breast which presented as solitary breast mass in a 56-year-old woman. She had a history of surgical excision of right foot for melanoma one year ago. The cytologic smears were composed of noncohesive epithelioid cells with round or eccentric nuclei, bi-or multi-nucleation, prominent nucleoli, fine chromatin, and intranuclear inclusions. The cytoplasm of tumor cells had scanty melanin pigment but were diffusely positive for S-100 protein.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.204-208
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• 2002

A Streptomyces sp. isolated from a soil sample collected in Taejeon, Korea has previously been found to produce two new polyene antibiotics. The two new antibiotics were named "16-methyloxazolomycin (antibacterial)" and "tetrin C (antifungal)", and their chemical structures are presented elsewhere [10, 11]. In the current study, chemotaxonomy, numerical taxonomy, and ISP methods were all employed for the taxonomic study. The spore chains were spirales and the spore surface was smooth. The spore mass was a gray series and no melanin pigment was produced. On the basis of the morphological and physiological properties, the microorganism was identified to be Streptomyces erumpens, belonging to the gray series of category IV, as defined by Bergey′s Manual. Tetrin C at the concentration of 20 ${\mu}g$/ml demonstrated a potent in vivo (pot test) preventive effect against rice blast, rice sheath blight, cucumber gray mold, wheat powdery mildew, and barley leaf rust.

• Korean Journal of Pharmacognosy
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• v.36 no.4 s.143
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• pp.273-277
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• 2005

In mammalian melanocytes, melanin synthesis is controlled by tyrosinase, the key enzyme in the pigment synthesis. In this study, to develop a new whitening agent, we have investigated the antioxidant and the inhibitory effect of Artemisia anomala extract on tyrosinase activity and melanigenesis in the B16/F1 melanoma cells. The inhibition ratio of tyrosinase activity of butanol fraction from A. anomala was higher than that of arbutin ($97.5{\pm}0.5%$ at the concentration of 2 mg/ml). The butanol fraction was shown scavenging activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and superoxide anion radicals in a dose dependent manner. The highest inhibitory activity of melanogenesis was also butanol fraction ($25.0{\pm}3%$ at the concentration of $200\;{\mu}g/ml$). From these results, we suggest that the A. anomala extract might be used to be a potential agent for skin whitening.

• Applied Microscopy
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• v.18 no.1
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• pp.49-59
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• 1988

Fine structures of the testis and vas deferens in the fall-web worm, Hyphantria cunea Drury, are studied with electron microscope. Adult worms have single testis close to the midlines of the abdomen. Testis is composed of 4 follicles which are incompletly separated from each other and bounded together by a peritoneal sheath. The peritoneal sheath consisted of outer cuticular layer and two kinds of inner layers, in which glycogen particles are dispersed commonly. These two layers are divided by the morphology of cytoplasmic granules. Follicular epithelium forming the wall of the follicles have melanin pigment granules, and trachea or tracheoles are extended through this epithelium. In the cysts of adult testis, matured spermatozoa are grouped together in bundles and after releasing the sperm bundles to the vas deferens, lamellar shaped lysosomes appeared in the cytoplasms of the cyst cells. The number of spermatozoa per cyst is exactly 256 ($2^8$), this number is characteristics of the Lepidoperan species. Vas deferens is a tube with a fairly thick bounding epithelium, a basement membrane and a layer of circular muscle outside it. At the apical portion of the epithelial cells, microvilli are well developed. And in the cytoplasms of these cells, numerous excretory granules are observed.

• Journal of Periodontal and Implant Science
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• v.41 no.4
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• pp.201-207
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• 2011

Purpose: The aim of this study is to compare two different gingival depigmentation techniques using an erbium:yttrium-aluminum-garnet (Er:YAG) laser and rotary instruments. Methods: Two patients with melanin pigmentation of gingiva were treated with different gingival depigmentation techniques. Ablation of the gingiva by Er:YAG laser was performed on the right side, and abrasion with a rotary round bur on the opposite side. Results: The patients were satisfied with the esthetically significant improvement with each method. However, some pigment still remained on the marginal gingival and papilla. The visual analog scale did not yield much difference between the two methods, with slightly more pain on the Er:YAG laser treated site. Conclusions: The results of these cases suggest that ablation of the gingiva by an Er:YAG laser and abrasion with a rotary round bur is good enough to achieve esthetic satisfaction and fair wound healing without infection or severe pain. Prudent care about the gingival condition, such as the gingival thickness and degree of pigmentation along with appropriate assessment is needed in ablation by the Er:YAG laser procedure.

• Korean Journal of Veterinary Research
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• v.45 no.3
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• pp.335-339
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• 2005

The melanocortin 1 receptor (MC1R) plays an important role in regulation of melanin pigment synthesis within mammalian melanocytes. Mutations within the gene encoding MC1R have been shown to explain coat color variations within several mammalian species including cattle. To develope a rapid and accurate method for the identification of Hanwoo, we performed a modified PCR-RFLP analysis of MC1R gene using single nucleotide polymorphism (SNP) within MC1R as a target. A size of 538 bp (537 bp for Hanwoo) was amplified by PCR, digested with Hpa II, and electrophoresed on a 1.5% agarose gel. A PCR product from Hanwoo showed a single band of 537 bp, whereas two fragments of 328 bp and 210 bp were detected in both Holstein and Black angus. The current result suggests that the PCR-RFLP using our primers and enzyme digestion system would be very accurate, easy and reproducible method to discriminate between Hanwoo and Holstein/Black angus meat.

• Korean Journal of Veterinary Research
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• v.45 no.1
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• pp.25-28
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• 2005

The melanocortin 1 receptor (MC1R) plays an important role in regulation of melanin pigment synthesis within mammalian melanocytes. Mutations within the gene encoding MC1R have been shown to explain coat color variations within several mammalian species including cattle. To develope a rapid and accurate method for the identification of Hanwoo meat, we performed a single nucleotide polymorphism (SNP) analysis in Melanocortin 1 receptor (MC1R) gene using TaqMan$^{(R)}$ MGB probe-based real-time PCR. Two specific probes (one for Hanwoo and the other for Holstein and Black angus) were designed. At the 5' end of 2 TaqMan$^{(R)}$ MGB probes, 6-carboxyfluorescein (FAM) was labeled for Hanwoo, and VIC for Holstein and Black angus. As a result, Hanwoo samples showed FAM-positive signal only, whereas other samples showed VIC-positive. This result suggests that the TaqMan$^{(R)}$ MGB probe based real-time PCR technique would be very accurate, easy and reproducible method to discriminate between Hanwoo meat and Holstein/Black angus meat.

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.235-237
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• 2006

When fruit bodies of Coprinellus congregatus were matured, they were autolysed to form black ink. During the developmental changes, cell walls of basidia were degraded. Laccase formed melanin which was the typical black pigment of fungi, and chitinase hydrolyzed the chitin which was a component of fungal cell wall. When laccase and chitinase genes were used as the probe for the Northern analysis to confirm their expression during the fruit body development, both gene expressions were increased as the mushroom was getting matured.