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Tyrosinase

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https://www.readbyqxmd.com/read/28448467/chemical-composition-and-biological-activities-of-mono-and-heterofloral-bee-pollen-of-different-geographical-origins
#1
Jucilene Silva Araújo, Emerson Dechechi Chambó, Maria Angélica Pereira de Carvalho Costa, Samira Maria Peixoto Cavalcante da Silva, Carlos Alfredo Lopes de Carvalho, Leticia M Estevinho
Recent research shows variations in pollen chemical constituents and, consequently, in their therapeutic properties. Mono and multifloral bee pollen extracts were investigated for antioxidant and enzyme inhibitory activity properties, phenolic compounds and fatty acid composition. Generally, Eucalyptus spp. and multifloral extracts exhibited potent inhibitory activity against α-amylase, acetylcholinesterase, tyrosinase, lipoxygenase, lipase and hyaluronidase. On the other hand, Miconia spp. demonstrated higher antihemolytic activity...
April 27, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28445987/context-dependent-mir-204-and-mir-211-affect-the-biological-properties-of-amelanotic-and-melanotic-melanoma-cells
#2
Marianna Vitiello, Andrea Tuccoli, Romina D'Aurizio, Samanta Sarti, Laura Giannecchini, Simone Lubrano, Andrea Marranci, Monica Evangelista, Silvia Peppicelli, Chiara Ippolito, Ivana Barravecchia, Elena Guzzolino, Valentina Montagnani, Michael Gowen, Elisa Mercoledi, Alberto Mercatanti, Laura Comelli, Salvatore Gurrieri, Lawrence W Wu, Omotayo Ope, Keith Flaherty, Genevieve M Boland, Marc R Hammond, Lawrence Kwong, Mario Chiariello, Barbara Stecca, Gao Zhang, Alessandra Salvetti, Debora Angeloni, Letizia Pitto, Lido Calorini, Giovanna Chiorino, Marco Pellegrini, Meenhard Herlyn, Iman Osman, Laura Poliseno
Despite increasing amounts of experimental evidence depicting the involvement of non-coding RNAs in cancer, the study of BRAFV600E-regulated genes has thus far focused mainly on protein-coding ones. Here, we identify and study the microRNAs that BRAFV600E regulates through the ERK pathway.By performing small RNA sequencing on A375 melanoma cells and a vemurafenib-resistant clone that was taken as negative control, we discover miR-204 and miR-211 as the miRNAs most induced by vemurafenib. We also demonstrate that, although belonging to the same family, these two miRNAs have distinctive features...
April 11, 2017: Oncotarget
https://www.readbyqxmd.com/read/28433680/organocatalyzed-and-mechanochemical-solvent-free-synthesis-of-novel-and-functionalized-bis-biphenyl-substituted-thiazolidinones-as-potent-tyrosinase-inhibitors-sar-and-molecular-modeling-studies
#3
Sadaf Mutahir, Muhammad Asim Khan, Islam Ullah Khan, Muhammad Yar, Muhammad Ashraf, Sidra Tariq, Ren-Long Ye, Bao-Jing Zhou
Eluding the involvement of solvents in organic synthesis and introducing environment friendly procedures can control environmental problems. A facile and an efficient solvent free mechanochemical method (grinding) is achieved to synthesize novel bis-biphenyl substituted thiazolidinones using non-toxic and cheap N-acetyl glycine (NAG). Organocatalytic condensation of a series of Schiff's bases bearing different substituents with thioglycolic acid produces a variety of thiazolidinones derivatives in good to excellent yield...
April 13, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28429191/melanogenesis-inhibition-in-mice-using-a-low-fluence-1064-nm-q-switched-neodymium-doped-yttrium-aluminum-garnet-laser-a-pilot-study
#4
Jae-Hui Nam, Joon Hong Min, Wang-Kyun Kim, Sunmin Yim, Won-Serk Kim
A low-fluence 1064-nm Q-switched neodymium-doped yttrium aluminum garnet laser, or laser toning, has yielded favorable outcomes in various benign pigmented disorders. However, the exact mechanism of action of laser toning has not been fully elucidated. We sought to determine the inhibitory effect of laser toning on melanogenesis and to assess how laser passes influence the outcomes. To produce perceptible pigmentation, nine HRM-2 melanin-possessing hairless mice were treated with ultraviolet (UV) B radiation on the dorsal skin...
April 20, 2017: Lasers in Medical Science
https://www.readbyqxmd.com/read/28425165/melanogenesis-inhibitory-and-cytotoxic-activities-of-limonoids-alkaloids-and-phenolic-compounds-from-phellodendron-amurense-bark
#5
Toshihiro Akihisa, Satoru Yokokawa, Eri Ogihara, Masahiro Matsumoto, Jie Zhang, Takashi Kikuchi, Kazuo Koike, Masahiko Abe
Four limonoids, 1-4, five alkaloids, 5-9, and four phenolic compounds, 10-13, were isolated from a MeOH extract of the bark of Phellodendron amurense (Rutaceae). Among these, compound 13 was a new, and its structure was established as rel-(1R,2R,3R)-5-hydroxy-3-(4-hydroxy-3-methoxyphenyl)-6-methoxy-1-(methoxycarbonylmethyl)indane-2-carboxylic acid methyl ester (γ-di(methyl ferulate)) based on the spectrometric analysis. Upon evaluation of compounds 1-13 against the melanogenesis in the B16 melanoma cells induced with α-melanocyte-stimulating hormone (α-MSH), four compounds, limonin (1), noroxyhydrastinine (6), haplopine (7), and 4-methoxy-N-methyl-2-quiolone (8), exhibited potent melanogenesis-inhibitory activities with almost no toxicity to the cells...
April 20, 2017: Chemistry & Biodiversity
https://www.readbyqxmd.com/read/28425134/record-broken-a-copper-peroxide-complex-with-enhanced-stability-and-faster-hydroxylation-catalysis
#6
Sonja Herres-Pawlis, Patricia Liebhäuser, Kristina Keisers, Alexander Hoffmann, Thomas Schnappinger, Isabella Sommer, Anne Thoma, Claudia Wilfer, Roland Schoch, Kai Stührenberg, Matthias Bauer, Maximilian Dürr, Ivana Ivanovic-Burmazovic
Tyrosinase model systems pinpoint pathways to translate nature´s synthetic abilities into useful synthetic catalysts. Mostly, they use N-donor ligands which mimic the histidine residues coordinating the two copper centres. Copper complexes with bis(pyrazolyl)methanes with pyridinyl or imidazolyl moieties are already reported as excellent tyrosinase models. Substitution of the pyridinyl donor results now in the new ligand HC(3 tBuPz)2(4 CO2MePy) which stabilises a room-temperature stable -2:2-peroxide dicopper(II) species upon oxygenation...
April 19, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28418429/chemical-constituents-radical-scavenging-activity-and-enzyme-inhibitory-capacity-of-fruits-from-cotoneaster-pannosus-franch
#7
Francisco Les, Víctor López, Giovanni Caprioli, Romilde Iannarelli, Dennis Fiorini, Marzia Innocenti, Maria Bellumori, Filippo Maggi
Cotoneaster pannosus (Rosaceae) is a semievergreen shrub, producing globose dark red pomes, native to China and widely used as an ornamental plant all over the world. Despite its extensive cultivation, little information is available on the chemical composition and biological activities of its fruits. In this work, the analysis of the chemical composition of C. pannosus fruits, in terms of phenolic components, carotenoids and ascorbic acid by HPLC/DAD, HPLC/ESI-MS and MS/MS as well as in terms of macro- and micro-nutrients was performed...
April 18, 2017: Food & Function
https://www.readbyqxmd.com/read/28414110/rifampicin-as-a-novel-tyrosinase-inhibitor-inhibitory-activity-and-mechanism
#8
Wei-Ming Chai, Mei-Zhen Lin, Fang-Jun Song, Ying-Xia Wang, Kai-Li Xu, Jin-Xin Huang, Jian-Ping Fu, Yi-Yuan Peng
In this study, the inhibitory effect and mechanism of rifampicin on the activity of tyrosinase were investigated for developing a novel tyrosinase inhibitor. It was found to have a significant inhibition on the activity of tyrosinase (IC50=90±0.6μM). From the kinetics analysis, it was proved to be a reversible and noncompetitive type inhibitor of the enzyme with the KI value of 94±3.5μM. The results obtained from intrinsic fluorescence quenching indicated that rifampicin could interact with tyrosinase. In particular, the drastic decrease of fluorescence intensity was due to the formation of a rifampicin-enzyme complex in a static procedure which was mainly driven by hydrophobic forces and hydrogen bonding...
April 13, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28410220/reprogramming-induced-by-isoliquiritigenin-diminishes-melanoma-cachexia-through-mtorc2-akt-gsk3%C3%AE-signaling
#9
Xiao-Yu Chen, De-Fang Li, Ji-Chun Han, Bo Wang, Zheng-Ping Dong, Li-Na Yu, Zhao-Hai Pan, Chuan-Jun Qu, Ying Chen, Shi-Guo Sun, Qiu-Sheng Zheng
Isoliquiritigenin (ISL), a member of the flavonoids, is known to have anti-tumor activity in vitro and in vivo. The effect of ISL on reprogramming in cancer cells, however, remains elusive. In this study, we investigated the effect of ISL on reprogramming in human melanoma A375 cells. ISL (15 μg/ml) significantly inhibited A375 cell proliferation, anchorage independent cell proliferation and G2/M cell cycle arrest after ISL exposure for 24 h. However, there were no significant changes in apoptosis rate. Terminal differentiation indicators (melanin content, melanogenesis mRNA expression, tyrosinase (TYR) activity) were all up-regulated by ISL treatment...
March 29, 2017: Oncotarget
https://www.readbyqxmd.com/read/28393917/inhibition-of-melanogenesis-by-jineol-from-scolopendra-subspinipes-mutilans-via-map-kinase-mediated-mitf-downregulation-and-the-proteasomal-degradation-of-tyrosinase
#10
Md Badrul Alam, Vivek K Bajpai, JungIn Lee, Peijun Zhao, Jung-Hee Byeon, Jeong-Sic Ra, Rajib Majumder, Jong Sung Lee, Jung-In Yoon, Irfan A Rather, Yong-Ha Park, Kangmin Kim, MinKyun Na, Sang-Han Lee
In this study, the authors investigated the anti-melanogenic effects of 3,8-dihydroxyquinoline (jineol) isolated from Scolopendra subspinipes mutilans, the mechanisms responsible for its inhibition of melanogenesis in melan-a cells, and its antioxidant efficacy. Mushroom tyrosinase activities and melanin contents were determined in melan-a cells, and the protein and mRNA levels of MITF, tyrosinase, TYRP-1, and TYRP-2 were assessed. Jineol exhibited significant, concentration-dependent antioxidant effects as determined by DPPH, ABTS, CUPRAC, and FRAP assays...
April 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28393568/assessment-of-radical-scavenging-whitening-and-moisture-retention-activities-of-panax-ginseng-berry-mediated-gold-nanoparticles-as-safe-and-efficient-novel-cosmetic-material
#11
Zuly Jiménez, Yeon-Ju Kim, Ramya Mathiyalagan, Kwang-Hoon Seo, Padmanaban Mohanan, Jong-Chan Ahn, Yu-Jin Kim, Deok Chun Yang
Panax ginseng berry extract possess remarkable pharmacological effects on skin treatment such as anti-aging, antioxidant, promotor of collagen synthesis and alleviation against atopic dermatitis. In recent years, gold nanoparticles have gained much attention due to their extensive range of applications in particular in the field of drug delivery as a result of their biological compatibility and low toxicity. In a previous study, we designed and developed biocompatible gold and silver nanoparticles based on phytochemical profile and pharmacological efficacy of P...
April 9, 2017: Artificial Cells, Nanomedicine, and Biotechnology
https://www.readbyqxmd.com/read/28392975/the-effect-of-retinal-melanin-on-optical-coherence-tomography-images
#12
Melissa A Wilk, Alison L Huckenpahler, Ross F Collery, Brian A Link, Joseph Carroll
PURPOSE: We assessed the effect of melanin on the appearance of hyperreflective outer retinal bands in optical coherence tomography (OCT) images. METHODS: A total of 23 normal subjects and 51 patients with albinism were imaged using the Bioptigen high-resolution spectral-domain OCT. In addition, three wild type, three albino (slc45a2(b4/b4) ), and eight tyrosinase mosaic zebrafish were imaged with the hand-held Bioptigen Envisu R2200 OCT. To identify pigmented versus nonpigmented regions in the tyrosinase mosaic zebrafish, en face summed volume projections of the retinal pigment epithelium (RPE) were created from volume scans...
April 2017: Translational Vision Science & Technology
https://www.readbyqxmd.com/read/28392894/anti-melanogenic-activity-of-viola-odorata-different-extracts-on-b16f10-murine-melanoma-cells
#13
Vafa Baradaran Rahimi, Vahid Reza Askari, Seyed Ahmad Emami, Zahra Tayarani-Najaran
OBJECTIVES: In previous studies, antioxidant activity of Viola odorata L. has been demonstrated. In this study, we have investigated the anti-melanogenic effect of extract and fractions of the plant in B16F10 cell line. MATERIALS AND METHODS: Impact of different increasing concentrations of extract and fractions of V. odorata was evaluated on cell viability, cellular tyrosinase, melanin content and mushroom tyrosinase as well as ROS production in B16F10 murine melanoma cell line...
March 2017: Iranian Journal of Basic Medical Sciences
https://www.readbyqxmd.com/read/28392381/the-light-subunit-of-mushroom-agaricus-bisporus-tyrosinase-its-biological-characteristics-and-implications
#14
Wangsa T Ismaya, Olivia M Tandrasasmita, Syaripah Sundari, Diana, Xuelei Lai, Debbie S Retnoningrum, Bauke W Dijkstra, Raymond R Tjandrawinata, Heni Rachmawati
The light subunit of mushroom Agaricus bisporus tyrosinase (LSMT) is a protein of unknown function that was discovered serendipitously during the elucidation of the crystal structure of the enzyme. The protein is non-immunogenic and can penetrate the intestinal epithelial cell barrier, and thus, similar to its structural homologue HA-33 from Clostridium botulinum, may be potentially absorbable by the intestine. LSMT also shares high structural homology with the ricin-B-like lectin from the mushroom Clitocybe nebularis (CNL), which has been shown to display biological activity against leukemic cancer cells and dendritic cells...
April 6, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28392346/uchl1-regulates-melanogenesis-through-controlling-mitf-stability-in-human-melanocytes
#15
Eun Young Seo, Seon-Pil Jin, Kyung-Cheol Sohn, Chi-Hyun Park, Dong Hun Lee, Jin Ho Chung
Ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) is involved in many signaling pathways via the ubiquitin-proteasome system. UCHL1 is expressed in the human skin and serves as a neuronal marker; however, its functions in melanogenesis remain unknown. Here, we investigated the role of UCHL1 in melanogenesis, and elucidated the underlying mechanism using human melanocytes. UCHL1 downregulation by siRNA resulted in upregulation of microphthalmia-associated transcription factor (MITF), tyrosinase, dopachrome tautomerase (DCT), tyrosinase-related protein 1 (TRP-1), and melanin...
April 6, 2017: Journal of Investigative Dermatology
https://www.readbyqxmd.com/read/28390858/combining-in%C3%A2-vitro-in%C3%A2-vivo-and-in-silico-approaches-to-evaluate-nutraceutical-potentials-and-chemical-fingerprints-of-moltkia-aurea-and-moltkia-coerulea
#16
Gokhan Zengin, Ramazan Ceylan, Jelena Katanić, Adriano Mollica, Abdurrahman Aktumsek, Tatjana Boroja, Sanja Matić, Vladimir Mihailović, Snežana Stanić, Zaahira Aumeeruddy-Elalfi, Mustafa Abdullah Yilmaz, Mohamad Fawzi Mahomoodally
Methanolic extracts of Moltkia aurea Boiss. (MA) and Moltkia coerulea (Willd.) Lehm. (MC) were investigated for their antioxidant capacity and enzymatic inhibitory potential against acetylcholinesterase, butyrylcholinesterase, α-amylase, α-glucosidase, and tyrosinase in vitro. MA and MC were also explored for their antimicrobial effect, as well as for their possible genotoxic/antigenotoxic potential on Drosophila melanogaster in vivo. The total bioactive components (phenolic (TPC) and flavonoid contents (TFC)) were determined and liquid chromatography-tandem mass spectrometry (LC-MS/MS) metabolite profiling of MA and MC appraised...
April 5, 2017: Food and Chemical Toxicology
https://www.readbyqxmd.com/read/28390782/anti-melanogenic-activity-of-phytosphingosine-via-the-modulation-of-the-microphthalmia-associated-transcription-factor-signaling-pathway
#17
Eun Jeong Jang, Yoonho Shin, Hyen Joo Park, Donghwa Kim, Cholomi Jung, Ji-Young Hong, Sanghee Kim, Sang Kook Lee
BACKGROUND: Microphthalmia-associated transcription factor (MITF) suppresses the expression of enzymes controlling the production of melanin. Phytosphingosine is a well-known cosmetic agent, but its anti-melanogenic activity and mechanism of action remain unclear. OBJECTIVE: This study was designed to investigate the effects of phytosphingosine on melanin synthesis and elucidate the plausible mechanism of actions in vitro and ex vivo systems. METHODS: Melanin content, cell viability, tyrosinase activity, p-CREB DNA binding activity, and the protein gene expression levels of the enzymes and proteins involved in melanogenesis were measured with the treatment of phytosphingosine...
March 23, 2017: Journal of Dermatological Science
https://www.readbyqxmd.com/read/28390091/inhibition-of-tyrosinase-by-4h-chromene-analogues-synthesis-kinetic-studies-and-computational-analysis
#18
Edikarlos M Brasil, Luciana M Canavieira, Érica T C Cardoso, Edilene O Silva, Jerônimo Lameira, José L M Nascimento, Vera L Eifler-Lima, Barbarella de Matos Macchi, Dharmarajan Sriram, Paul V Bernhardt, José Rogério Araújo Silva, Craig M Williams, Cláudio N Alves
Inhibition of mushroom tyrosinase was observed with synthetic dihydropyrano[3,2-b]chromenediones. Among them, DHPC04 displayed the most potent tyrosinase inhibitory activity with a Ki value of 4μM, comparable to the reference standard inhibitor kojic acid. A kinetic study suggested that these synthetic heterocyclic compounds behave as competitive inhibitors for the L-DOPA binding site of the enzyme. Furthermore, molecular modeling provided important insight into the mechanism of binding interactions with the tyrosinase copper active site...
April 8, 2017: Chemical Biology & Drug Design
https://www.readbyqxmd.com/read/28389280/in-vitro-safety-and-efficacy-evaluations-of-a-complex-botanical-mixture-of-eugenia-dysenterica-dc-myrtaceae-prospects-for-developing-a-new-dermocosmetic-product
#19
Larissa Cleres Moreira, Renato Ivan de Ávila, Danillo Fabrini Maciel Costa Veloso, Tatiana Nascimento Pedrosa, Emerson Silva Lima, Renê Oliveira do Couto, Eliana Martins Lima, Aline Carvalho Batista, José Realino de Paula, Marize Campos Valadares
In the context of developing a new natural product-based cosmetic, the in vitro efficacy and safety evaluations of a complex botanical mixture based on Eugenia dysenterica leaf hydroalcoholic extract (EDE) (2.5-1000μg/mL) were carried out. Chromatographic analysis demonstrated the presence of the tannin (ellagic acid) and flavonoids (quercetin and gallic acid) which characterize the EDE as a polyphenol-rich mixture. Using HFF-1 fibroblasts, it was shown that EDE promoted cell regeneration after UVA exposure...
April 4, 2017: Toxicology in Vitro: An International Journal Published in Association with BIBRA
https://www.readbyqxmd.com/read/28388092/spectrophotometric-characterization-of-the-action-of-tyrosinase-on-p-coumaric-and-caffeic-acids-characteristics-of-o-caffeoquinone
#20
Antonio Garcia-Jimenez, Jose Luis Munoz-Munoz, Francisco García-Molina, Jose Antonio Teruel-Puche, Francisco García-Cánovas
New methods are proposed to determine the activity of tyrosinase on caffeic and p-coumaric acids. Because o-quinone from caffeic acid is unstable in its presence, it has been characterized through spectrophotometric measurements of the disappearance of coupled reducing agents, such as nicotinamide adenine dinucleotide reduced form. It has also been characterized by a chronometric method, measuring the time that a known concentration of ascorbic acid takes to be consumed. The activity on p-coumaric acid has been followed by measuring the formation of o-quinone of caffeic acid at the isosbestic point originated between caffeic acid and o-caffeoquinone and measuring the formation of o-quinone at 410 nm, which is stable in the presence of p-coumaric acid (both of them in the presence of catalytic amounts of caffeic acid, maintaining the ratio between p-coumaric acid and caffeic acid constant; R = 0...
April 18, 2017: Journal of Agricultural and Food Chemistry
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