姜黄素对黑素的抑制作用及机制北大核心CSCD

目的姜黄素调节B16F10细胞微环境影响黑素合成的机制研究。方法(1)不同浓度姜黄素分别作用于B16F10及HaCaT细胞,MTT法检测该两种细胞活力;NaOH裂解法检测B16F10细胞黑素含量;L-DOPA氧化法检测B16F10细胞酪氨酸酶活性;Western blot法检测B16F10细胞黑素生成(gp100、Mitf、GPNMB、Tyr、TRP2)及转运(Rab27a)关键蛋白表达水平;HaCaT细胞:ISG15蛋白表达水平。(2)不同浓度ISG15作用于B16F10细胞,NaOH裂解法检测黑素含量;L-DOPA氧化法检测酪氨酸酶活性;结果姜黄素在一定浓度范围内,直接抑制酪氨酸酶活性及黑素生成,且抑制黑素细胞迁移;ISG15蛋白作用于黑素细胞,明显促进gp100蛋白表达,酪氨酸酶活力,黑素含量。姜黄素抑制HaCaT细胞ISG15蛋白表达,改变黑素细胞微环境,通过ISG15间接发挥抑制黑素合成作用。结论姜黄素除直接抑制黑素合成外,还可以通过抑制ISG15蛋白的表达,改变黑素细胞微环境,间接发挥抑制黑素合成作用。     

中药对人黑素细胞酪氨酸酶活性及黑素合成的影响效果

目的：探讨刺蒺藜、黄芩苷对体外培养人黑素细胞（Melanocyte,MC）及其与角质形成细胞（Keratinoeyte,KC）共培养体系中酪氨酸酶（Tyrosinase,TYR）活性及黑素合成的影响效果。方法培养人表皮黑素细胞及黑素细胞与角质形成细胞共培养体系,利用MTT法、多巴氧化法及NaOH法测定刺蒺藜、黄芩苷对黑素细胞的增殖、酪氨酸酶活性及黑素合成的影响,以补骨脂素作为对照。结果刺蒺藜、黄芩苷均可促进酪氨酸酶活性及增加黑素合成,但对共培养体系中黑素细胞的作用强于体外纯黑素细胞的作用（P<0.05）;在对酪氨酸酶活性的影响中,黄芩苷的作用强于刺蒺藜,其差异具有统计学意义（P<0.05）;在对黑素合成的作用上,刺蒺藜强于黄芩苷（P<0.05）。结论刺蒺藜、黄芩苷对人黑素细胞酪氨酸酶活性及黑素合成均有较强的促进作用,且对共培养体系的作用强于对纯黑素细胞的作用。     

具抑制酪氨酸酶活性祛斑增白药物

据统计,约有７０％的被调查者认为美容的最大障碍之一是面部雀斑、黄褐斑、老年斑的形成。这些色斑的形成是由于皮肤产生黑色素过多所致。而黑色素形成又与酪氨酸酶密切相关,抑制酪氨酸酶活性便能减少黑色素的生成［１．２］。据此,选择具有抑制酪氨酸酶活性的药物,添加于适宜制剂中,涂擦患部即可达到祛斑美容之目的。具有抑制酪氨酸酶活性的药物为数不少,本文就此作如下介绍。１　化学药品以往应用较多的主要有：氢醌（对苯二酚）、壬二酸及汞化合物（氯化汞、白降汞等）等。也有用对苯二酚和壬二酸霜治疗黄褐斑均取得了较好效果的报…     

驱虫斑鸠菊提取物抑制恶性黑色素瘤A375细胞增殖的研究

目的探讨驱虫斑鸠菊提取物对人恶性黑色素瘤A375细胞的增殖以及对其酪氨酸酶活性和黑色素含量的影响。方法四甲基噻唑氮蓝比色法测定对A375细胞抑制作用;显微法观察细胞形态;比色法测定酪氨酸酶活性和黑色素含量。结果在一定质量浓度范围(1～40mg.L-1)内随着驱虫斑鸠菊提取物质量浓度增加可抑制黑色素瘤细胞的增殖;驱虫斑鸠菊提取物质量浓度小于10mg.L-1,对酪氨酸酶活性和黑色素合成抑制有增加的趋势;大于20mg.L-1时,显示一定的细胞毒性作用。结论驱虫斑鸠菊提取物能显著抑制恶性黑色素瘤A375细胞的增殖,在一定质量浓度范围内(1～40mg.L-1)有浓度依赖关系(P<0.05)。     

银杏叶中抑制酪氨酸酶活性的成分研究

目的 探明银杏叶中对酪氨酸酶具有抑制作用的活性成分。方法 以体外酪氨酸酶活性抑制检测为导向，对银杏叶提取物中具有抑制活性的萃取部位采用正相、反相硅胶柱色谱和制备HPLC等方法进行逐级分离纯化，获得部分具有抑制活性的化合物，并采用核磁等波谱技术鉴定其结构。结果 从银杏叶95%乙醇提取物中分离纯化，获得了5个对酪氨酸酶具有抑制活性的化合物，分别鉴定为：白果内酯(Ⅰ)、原儿茶酸(Ⅱ)、对香豆酸(Ⅲ)、对羟基苯甲酸(Ⅳ)、间羟基苯甲酸(Ⅴ)。结论 银杏叶中含有能抑制酪氨酸酶的活性成分，具有开发成抑制皮肤黑色素生成药物或美白化妆品的潜在应用价值。     

松茸及多种植物提取物的美白功效研究

目的评价松茸、桑白皮、虎杖及葛根提取物对酪氨酸酶活性及黑色素合成的抑制作用,为美白类产品的开发提供试验依据。方法测定不同浓度松茸、桑白皮、虎杖及葛根提取物对酪氨酸酶活性,B16细胞增殖的影响及对B16细胞内黑色素含量及酪氨酸酶活性的抑制作用。以阳性药光甘草定作为对照。采用SigmaStat软件进行统计学处理。结果在B16细胞模型中,松茸提取物抑制活性优于桑白皮、虎杖和葛根提取物（P〈0.05）,高浓度（25 mg/L）松茸提取物对黑色素合成及酪氨酸酶活性的抑制率分别为（46.70±7.79）%和（65.73±0.58）%,与光甘草定的作用效果相当[抑制率分别是（30.48±3.05）%和（73.53±0.80）%]。结论高浓度松茸提取物对酪氨酸酶活性及黑色素合成的抑制作用与光甘草定相当,其作为天然来源的皮肤美白剂具有一定的开发潜力。     

牛磺酸对酪氨酸酶的抑制作用

酪氨酸酶的活性与黑色素的形成有关。用Ｌ－酪氨酸作底物,测定了牛磺酸对酪氨酸酶的非竞争性抑制。其抑制常数为５３．７Ｍｇ／Ｌ,牛磺酸浓度为３２μｇ／ｍｌ时,最大抑制率为３５．３％。牛磺酸有望成为治疗和预防黑色素疾病的药物。     

三叶青提取物对A375细胞增殖、酪氨酸酶活性及黑色素合成的影响

目的探讨三叶青乙醇提取物对人恶性黑色素瘤A375细胞增殖、酪氨酸酶活性及黑色素合成的影响。方法 采用MTT比色法,测定不同浓度三叶青乙醇提取物对A375细胞体外抑制作用;比色法测定酪氨酸酶活性和黑色素含量。结果在质量浓度为1～625μg/ml范围内,随着三叶青乙醇提取物浓度增大可抑制A375细胞的增殖(P<0.01);三叶青乙醇提取物浓度在1～5μg/ml时,对酪氨酸酶活性和黑色素合成抑制有增加趋势;而在25～625μg/ml时,对A375细胞有一定毒性。结论三叶青乙醇提取物在一定浓度范围内(1～625μg/ml)能抑制A375细胞的增殖,且呈剂量依赖关系。     

丁香精油对黑色素细胞抗氧化特性及黑色素生成的影响

目的:考察丁香精油对体外培养的黑色素细胞抗氧化特性的变化及对黑色素生成抑制作用,为精油在食品、化妆品等领域的应用提供理论支撑.方法:通过测定精油作用后细胞增殖活力,选择合适的药物浓度.然后用不同浓度精油作用细胞,测定细胞内T-SOD、ROS的含量、黑色素含量和酪氨酸酶相对活性.结果:MTT法可知丁香精油最大无毒浓度为0.084mg/mL,用于后续试验,可显著抑制黑色素细胞生长,抑制率与药物浓度正相关.细胞经药物作用48h后,细胞内T-SOD增加,ROS下降,黑色素含量和酪氨酸酶活性下降.结论:丁香精油具有抗氧化性及抑制黑色素细胞黑色素生成的功效.     

氢化可的松对B-16黑素瘤细胞酪氨酸酶及黑素生成影响研究

目的　探讨氢化可的松体外对酪氨酸酶活性影响 ,以及对小鼠B 16黑素瘤细胞株细胞增殖、黑素合成以及细胞内酪氨酸酶活性的作用。方法　利用四甲基偶氮唑蓝(MTT)比色法测定药物对细胞增殖的影响 ;采用酶学方法研究药物对酪氨酸酶活性的影响 ;用 5 70nm比色法测定黑素含量。结果　氢化可的松体外可激活酪氨酸酶活性 ,增强B16鼠黑素瘤细胞增殖 ,提高酪氨酸酶和黑色素合成能力。结论　氢化可的松可增强酪氨酸酶活性 ,进而促进黑素合成。     

Gentamicin affects melanogenesis in normal human melanocytes

Background: Aminoglycoside antibiotics, including gentamicin, despite their ability to induce adverse effects on pigmented tissues, remain valuable and sometimes indispensable for the treatment of various infections. It is known that gentamicin binds to melanin biopolymers, but the relation between this drug affinity to melanin and its toxicity is not well documented. The aim of this work was to examine the impact of gentamicin on viability and melanogenesis in HEMa-LP (light pigmented) and HEMn-DP (dark pigmented) normal human melanocytes.

Methodology/principal findings: The effect of gentamicin on cell viability was determined by 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate (WST-1) assay; melanin content and tyrosinase activity were measured spectrophotometrically. It has been demonstrated that gentamicin induces concentration-dependent loss in melanocytes viability. The application of antibiotic in concentration of 10?mM causes higher reduction in viability of the light pigmented melanocytes (by about 74%) when compared with the dark pigmented ones (by about 62%). The value of the concentration of a drug that produces loss in cell viability by 50% (EC₅₀) for both cell lines was found to be ～7.5?mM. It has been shown that gentamicin causes inhibition of tyrosinase activity and reduces melanin content in light pigmented melanocytes significantly more than in the dark pigmented cells.

Conclusion/significance: We have found that gentamicin modulates melanization process in melanocytes in vitro, what may explain the potential role of melanin biopolymer in the mechanisms of undesirable toxic effects of this drug in vivo, as a result of its accumulation in pigmented tissues. We have also stated that the melanogenesis process in light pigmented melanocytes is more sensitive to the inhibitory effect of gentamicin than in the dark pigmented cells.     

Depigmentation of melanocytes by the treatment of extracts from traditional Chinese herbs: a cell culture assay

OBJECTIVE: To obtain potential skin whitening agents from traditional Chinese herbs, we tested changes of melanin content in melanocyte cell lines after treatment with extracts of 90 traditional Chinese herbs. METHODS: Mouse melanocyte cell lines were used. Depigmentation activity of the herb extracts were first screened in Mel-Ab cells, and then re-evaluated in melan-a cells and co-culture of melan-a and SP-1 cells. Melanin content and cell viability were the two indications for evaluation. Tyrosinase activity and the expression of melanin synthesis related enzymes in cells treated with the herb extracts were also tested. RESULTS: Nine herb extracts were proved to have depigmentation activity similar to or better than that of arbutin and low cytotoxicity to melanocytes. Two of them were more effective in co-cultured melan-a cells. Most of the effective herb extracts inhibited tyrosinase activity and the expression of tyrosinase. Some of them also inhibited tyrosinase related protein-1 and/or tyrosinase related protein-2 in cultured cells. CONCLUSIONS: We have found 9 herb extracts to be promising skin whitening agents. Among them, water extract of Galla Chinensis and ethanol extract of Radix Clematidis exhibited higher depigmentation activity and caused lower tyrosinase activity in cell culture assays and are worthy to be further studied.     

Interaction between ciprofloxacin and melanin: the effect on proliferation and melanization in melanocytes

There have been described serious adverse events caused by ciprofloxacin in pigmented tissues. It is known that some fluoroquinolones bind well to melanin rich tissues, but the relation between their affinity to melanin and the skin or eye toxicity is not well documented. The aim of this study was to examine whether ciprofloxacin binds to melanin, and how this interaction affects the proliferation and melanization in melanocytes. We have demonstrated that complexes which ciprofloxacin forms with melanin possess at least two classes of independent binding sites. Their association constants are K(1)~10(5) M(-1) and K(2)~10(2) M(-1), respectively. Ciprofloxacin has induced evident concentration-dependent loss in melanocytes viability. The value of ED(50) was found to be ~0.5 mM. It has also been shown that ciprofloxacin reduces melanin content, and decreases tyrosinase activity in human skin melanocytes. The ability of ciprofloxacin to interact with melanin and its inhibitory effect on melanization in melanocytes in vitro may explain a potential role of melanin in the mechanisms of ciprofloxacin toxic effects in vivo.     

Temperature regulates melanin synthesis in melanocytes

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 degrees C) produce less melanin than cells at 37 degrees 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 degrees C for 1 h or 3 h did not affect tyrosinase activity or melanin synthesis, whereas long exposures to 31 degrees 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.     

Inhibitory effects of cinnamic acid on melanin biosynthesis in skin

Cinnamic acid is a wildly distributed phenylpropanoid component naturally occurring in plants, and is mainly found in Cinnamomum cassia BLUME and Panax ginseng. Cinnamic acid was recently reported to exert a tyrosinase inhibitory effect. However, research on melanocytes and animal bodies was not reported until now. In this study, we examined the effects of cinnamic acid on melanin biosynthesis within the melanocytes and brown guinea pigs. Melan-a cells were used to examine the effects of cinnamic acid in the melanocytes. Treatment with 100 ppm of cinnamic acid resulted in a significant reduction of melanin production in the melan-a cells at 29.0%. This compound also exhibited a potent inhibitory effect on tyrosinase activity and reduced tyrosinase expression in the melan-a cells. Moreover, cinnamic acid exhibited depigmenting activity on the UV-B-induced hyperpigmentation of brown guinea pig skin. Our results suggest that cinnamic acid might act as a skin whitening agent via inhibition of tyrosinase activity and expression within melanocytes.     

Effect of fluoroquinolones on melanogenesis in normal human melanocytes HEMn-DP: a comparative in vitro study

Purpose: Fluoroquinolones are one of the most commonly prescribed classes of antibiotics. However, their use is often connected with high risk of phototoxic reactions that lead to various skin or eye disorders. The aim of this study was to examine the effect of ciprofloxacin, lomefloxacin, moxifloxacin and fluoroquinolone derivatives with different phototoxic potential, on the viability and melanogenesis in melanocytes.

Materials and methods: Normal human epidermal melanocytes, dark pigmented (HEMn-DP) were used as an in vitro model system. The effect of the tested antibiotics on cell viability and melanization in pigmented cells was investigated using a spectrophotometric method. The WST-1 assay was used to detect the cytotoxic effect of antibiotics.

Results: Ciprofloxacin, lomefloxacin and moxifloxacin induced the concentration-dependent loss in melanocytes viability. The values of EC₅₀ for the tested fluoroquinolone derivatives were found to be 2.0?mM for ciprofloxacin, 0.51?mM for lomefloxacin and 0.27?mM for moxifloxacin. The exposure of cells to different concentrations of the analyzed drugs resulted in decrease in melanin content and tyrosinase activity. The highest decrease was observed for lomefloxacin which may explain its high phototoxic potential in vivo. The role of melanin in the mechanism of the toxicity of fluoroquinolones was discussed and the obtained results were compared with the previously obtained data concerning light-pigmented melanocytes (HEMa-LP).

Conclusions: The results obtained in vitro suggest that the phototoxic potential of fluoroquinolones in vivo depends on specific drug–melanin interaction, the ability of drugs to affect melanogenesis as well as on the degree of melanocytes pigmentation.     

鱿鱼皮胶原蛋白多肽对B16黑素瘤细胞黑素合成的影响

目的研究不同分子量鱿鱼皮胶原蛋白多肽SP1(Mr>10000u)、SP2(6000u相似文献   

Dimeric cinnamoylamide derivatives as inhibitors of melanogenesis

Dimeric cinnamoylamide derivatives were synthetized and tested as inhibitors of tyrosinase activity and melanin formation. The most active dimeric cinnamoylamide derivatives was dimeric compound of p-coumaric acid (compound 1) that inhibited tyrosinase activity more efficiently than p-coumaric acid. It also inhibited melanin production by B16 melanoma cell line and normal human melanocytes more efficiently than kojic acid. We next investigated the potential mutagenic and skin sensitization effect of compound 1. Compound 1 was found to induce no mutagenic activity, no irritation and no delayed contact hypersensitivity at the maximum concentration of 10%. In vitro percutaneous absorption studies exhibited that compound 1 could diffuse across the skin till its site of action. All these results lead us to propose that compound 1 may be a safe and effective candidate for treating skin hyperpigmentation related disorders.