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Tyrosinase

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https://www.readbyqxmd.com/read/28069121/investigating-the-inhibitory-activity-and-mechanism-differences-between-norartocarpetin-and-luteolin-for-tyrosinase-a-combinatory-kinetic-study-and-computational-simulation-analysis
#1
Long Zhang, Xin Zhao, Guan-Jun Tao, Jie Chen, Zong-Ping Zheng
Flavonoids are an important type of natural tyrosinase inhibitor, but their inhibitory activity and mechanism against tyrosinase are very different because of their different structures. In this study, the inhibitory activity and mechanism differences between norartocarpetin and luteolin for tyrosinase were investigated by a combination of kinetic studies and computational simulations. The kinetic analysis showed that norartocarpetin reversibly inhibited tyrosinase in a competitive manner, whereas luteolin caused reversible noncompetitive inhibition...
May 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28054996/production-and-anti-melanoma-activity-of-methoxyisoflavones-from-the-biotransformation-of-genistein-by-two-recombinant-escherichia-coli-strains
#2
Chien-Min Chiang, Yu-Jhe Chang, Jiumn-Yih Wu, Te-Sheng Chang
Biotransformation of the soy isoflavone genistein by sequential 3'-hydroxylation using recombinant Escherichia coli expressing tyrosinase from Bacillus megaterium and then methylation using another recombinant E. coli expressing O-methyltransferase from Streptomyces peucetius was conducted. The results showed that two metabolites were produced from the biotransformation, identified as 5,7,4'-trihydroxy-3'-methoxyisoflavone and 5,7,3'-trihydroxy-4'-methoxyisoflavone, respectively, based on their mass and nuclear magnetic resonance spectral data...
January 4, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28052521/a-bioluminogenic-probe-for-monitoring-tyrosinase-activity
#3
Jianguang Wang, Taesup Lee, Zhe Zhang, Ching Tung
A novel bioluminogenic probe, based on luciferin, was designed and synthesized to monitor tyrosinase activity. Its applications were demonstrated in assessing tyrosinase activity in a buffered aqueous solution, and in measuring endogenous tyrosinase activity in melanoma cells.
January 3, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28051915/alisol-b-a-triterpene-from-alismatis-rhizoma-dried-rhizome-of-alisma-orientale-inhibits-melanin-production-in-murine-b16-melanoma-cells
#4
Ichiro Yoshida, Chihiro Ito, Shinya Matsuda, Akihiko Tsuji, Noriyuki Yanaka, Keizo Yuasa
To develop new whitening agents from natural products, we screened 80 compounds derived from crude drugs in Kampo medicine in a melanin synthesis inhibition assay using murine B16 melanoma cells. The screen revealed that treatment with alisol B, a triterpene from Alismatis rhizoma, significantly decreased both melanin content and cellular tyrosinase activity in B16 cells. However, alisol B did not directly inhibit mushroom tyrosinase activity in vitro. Therefore, we investigated the mechanism underlying the inhibitory effect of alisol B on melanogenesis...
January 4, 2017: Bioscience, Biotechnology, and Biochemistry
https://www.readbyqxmd.com/read/28040595/euphorbia-denticulata-lam-a-promising-source-of-phyto-pharmaceuticals-for-the-development-of-novel-functional-formulations
#5
Gokhan Zengin, Ahmet Uysal, Abdurrahman Aktumsek, Andrei Mocan, Adriano Mollica, Marcello Locatelli, Luisa Custodio, Nuno R Neng, José M F Nogueira, Zaahira Aumeeruddy-Elalfi, M Fawzi Mahomoodally
In this study, Methanolic extracts of Euphorbia denticulata parts (flowers, leaf, stem, and mix of aerial parts) were assessed for a panoply of bioactivities. Inhibitory potential against key enzymes involved in diabetes (α-glucosidase and α-amylase), obesity (pancreatic lipase), neurodegenerative diseases (cholinesterases), and hyperpigmentation (tyrosinase) was evaluated. The antioxidant and antibacterial properties were also assessed. The total phenolic, flavonoid, and phytochemical profile were established using HPLC/DAD and molecular modelling studies on specific target compounds were performed in silico...
December 29, 2016: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
https://www.readbyqxmd.com/read/28038744/characterization-of-glabridin-hydroxypropyl-%C3%AE-cyclodextrin-inclusion-complex-with-robust-solubility-and-enhanced-bioactivity
#6
Yongqin Wei, Jin Zhang, Yan Zhou, Weiya Bei, Yuan Li, Qipeng Yuan, Hao Liang
Various biological activities of glabridin have been reported in literature, however, the bioavailability and clinical application was limited by its low water solubility. In this study, we developed a novel inclusion complex of glabridin and hydroxypropyl-β-cyclodextrin (HP-β-CD) that features improved solubility and bioactivity. The formation of the inclusion complex was supported by data from FT-IR, PXRD, SEM and NMR. Specifically, the NMR results indicated that the aromatic ring of glabridin was merged into and located at the narrow side the cavity of HP-β-CD...
March 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28032664/synthesis-of-novel-pyrazolines-their-boron-fluorine-complexes-and-investigation-of-antibacterial-antioxidant-and-enzyme-inhibition-activities
#7
Nuran Kahriman, Zeynep Haşimoğlu, Vildan Serdaroğlu, Fatih Şaban Beriş, Burak Barut, Nurettin Yaylı
New 3,5-disubstituted-2-pyrazoline derivatives (4-6), their boron-fluorine complexes (boron (3-(2'-aminophenyl),5-(2'-/3'-/4'-pyridyl)pyrazoline, BOAPPY) (7-9) and boron 1,2'-diazaflavone complex (BODAF) (11) were synthesized starting from azachalcones (1-3) to diazaflavone (10), respectively. Biological evaluation of compounds 4-9 and 11 showed remarkable antioxidant, antibacterial, and acetylcholinesterase and tyrosinase enzyme inhibition activities. All newly synthesized compounds 4-9 and 11 showed respectable antibacterial effect with minimum inhibitory concentrations in the range of 4...
December 29, 2016: Archiv der Pharmazie
https://www.readbyqxmd.com/read/28029781/aryl-hydrocarbon-receptor-activation-contributes-to-benzanthrone-induced-hyperpigmentation-via-modulation-of-melanogenic-signaling-pathways
#8
Sabiya Abbas, Shamshad Alam, Krishna P Singh, Mahadeo Kumar, Shailendra K Gupta, Kausar M Ansari
Benzanthrone (BA), an oxidized polycyclic aromatic hydrocarbon (PAH), has been found to be a potential health threat to occupational workers involved in dye manufacturing factories. It has been observed that occupational workers become exposed to BA either during manufacturing, pulverization, or storage and developed various kinds of skin diseases like contact dermatitis, itching, erythema, roughness, and foremost, hyperpigmentation. It has been shown that some environmental organic pollutants (POPs) like dioxins, furans, and polychlorinated biphenyls (PCBs) may act as ligands for the aryl hydrocarbon receptor (AhR) and regulate hyperpigmentation...
January 12, 2017: Chemical Research in Toxicology
https://www.readbyqxmd.com/read/28028844/improved-tlc-bioautographic-assay-for-qualitative-and-quantitative-estimation-of-tyrosinase-inhibitors-in-natural-products
#9
Jinge Zhou, Qingjiu Tang, Tao Wu, Zhihong Cheng
INTRODUCTION: TLC bioautography for tyrosinase inhibitors has made recent progress; however, an assay with a relative low consumption of enzyme and quantitative capability would greatly advance the efficacy of related TLC bioautographic assays. OBJECTIVE: An improved TLC bioautographic assay for detecting tyrosinase inhibitors was developed and validated in this study. METHODS: L-DOPA (better water-solubility than L-tyrosine) was used as the substrate instead of reported L-tyrosine...
December 28, 2016: Phytochemical Analysis: PCA
https://www.readbyqxmd.com/read/28026947/biodegradable-kojic-acid-based-polymers-controlled-delivery-of-bioactives-for-melanogenesis-inhibition
#10
Jonathan J Faig, Alysha Moretti, Laurie B Joseph, Yingyue Zhang, Mary Joy Nova, Kervin Smith, Kathryn E Uhrich
Kojic acid (KA) is a naturally occurring fungal metabolite that is utilized as a skin-lightener and anti-browning agent owing to its potent tyrosinase inhibition activity. While efficacious, KA's inclination to undergo pH-mediated, thermal-, and photo-degradation reduces its efficacy, necessitating stabilizing vehicles. To minimize degradation, poly(carbonate-esters) and polyesters comprised of KA and natural diacids were prepared via solution polymerization methods. In vitro hydrolytic degradation analyses revealed KA release was drastically influenced by polymer backbone composition (e...
December 27, 2016: Biomacromolecules
https://www.readbyqxmd.com/read/28019642/recent-updates-on-melanocyte-biology-and-the-use-of-promising-bioactive-compounds-for-the-treatment-of-hypopigmentary-disorders-a-review
#11
Sharique A Ali, Ishrat Naaz, Kamal Uddin Zaidi, Ayesha Sharique Ali
Skin pigmentation is a broadly appearing phenomenon in nature which plays an important task of determining the appearance and biology of all vertebrates including human beings. Skin color is a crucial attribute, determined by the synthesis of melanin pigment within melanocytes by the process of melanogenesis and is regulated by many extrinsic as well as intrinsic factors. Tyrosinase catalyzes the key step of melanogenesis, dysfunction of tyrosinase leads to reduce melanin production which results in severe clinical and aesthetical problems of hypopigmentation...
December 23, 2016: Mini Reviews in Medicinal Chemistry
https://www.readbyqxmd.com/read/28017864/modifying-effects-of-carboxyl-group-on-the-interaction-of-recombinant-s100a8-a9-complex-with-tyrosinase
#12
Fatemeh NematiNiko, Koorosh Goodarzvand Chegini, Hamideh Asghari, Abbas Amini, Nematollah Gheibi
Tyrosinase is a determinant enzyme for modulating melanin production as its abnormal activity can result in an increased amount of melanin. Reduction of tyrosinase activity has been targeted for preventing and healing hyperpigmentation of skin, such as melanoma and age related spots. The aim of this systematic study is to investigate whether recombinant S100A8/A9 and its modified form reduce the activity of mushroom tyrosinase (MT) through changing its structure. Recombinant His-Tagged S100A8 and S100A9 are expressed in Escherichia coli BL21 (DE3) and modified using Woodward's reagent K which is a carboxyl group modifier...
December 22, 2016: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28012343/hydroxylated-biphenyls-as-tyrosinase-inhibitor-a-spectrophotometric-and-electrochemical-study
#13
Paolo Ruzza, Pier Andrea Serra, Davide Fabbri, Maria Antonietta Dettori, Gaia Rocchitta, Giovanna Delogu
A small collection of C2-symmetry hydroxylated biphenyls was prepared by straightforward methods and the capability to act as inhibitors of tyrosinase has been evaluated by both spectrophotometric and electrochemical assays. Our attention was focused on the diphenolase activity of this enzyme characterized by the absence of the characteristic lag time of enzymatic reaction of its monophenolase activity. To this purpose, we evaluated the capability of tyrosinase to oxidize a natural o-diphenol substrate to o-quinone analyzing the changes in the UV-Vis spectrum of a solution of caffeic acid and the reduction of the cathodic current in a tyrosinase-biosensor, respectively...
December 13, 2016: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28012319/a-novel-fluorimetric-sensing-platform-for-highly-sensitive-detection-of-organophosphorus-pesticides-by-using-egg-white-encapsulated-gold-nanoclusters
#14
Xu Yan, Hongxia Li, Tianyu Hu, Xingguang Su
Assays for organophosphorus pesticides (OPs) with high sensitivity as well as on-site screening have been urgently required to protect ecosystem and prevent disease. Herein, a novel fluorimetric sensing platform was constructed for quantitative detection of OPs via tyrosinase (TYR) enzyme-controlled quenching of gold nanoclusters (AuNCs). One-step green synthetic approach was developed for the synthesis of AuNCs by using chicken egg white (CEW) as template and stabilizer. Initially, TYR can catalyze the oxidation of dopamine to dopaminechrome, which can efficiently quench the fluorescence intensity of AuNCs at 630nm based on dynamic quenching process...
November 25, 2016: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28011217/synthesis-and-biological-evaluation-of-novel-hydroxybenzaldehyde-based-kojic-acid-analogues-as-inhibitors-of-mushroom-tyrosinase
#15
Wenlin Xie, Huilin Zhang, Jingjing He, Jingai Zhang, Qiuyan Yu, Chunxiang Luo, Shangru Li
Two series of novel kojic acid analogues (4a-j) and (5a-d) were designed and synthesized, and their mushroom tyrosinase inhibitory activities was evaluated. The result indicated that all the synthesized derivatives exhibited excellent tyrosinase inhibitory properties having IC50 values in the range of 1.35±2.15-17.50±2.75μM, whereas standard inhibitor kojic acid have IC50 values 20.00±1.08μM. Specifically, 5-phenyl-3-[5-hydroxy-4-pyrone-2-yl-methylmercap-to]-4-(2,4-dihydroxyl-benzylamino)-1,2,4-triazole (4f) exhibited the most potent tyrosinase inhibitory activity with IC50 value of 1...
December 9, 2016: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28006914/antioxidant-flavonols-and-phenolic-compounds-from-atraphaxis-frutescens-and-their-inhibitory-activities-against-insect-phenoloxidase-and-mushroom-tyrosinase
#16
Batsukh Odonbayar, Toshihiro Murata, Javzan Batkhuu, Kosho Yasunaga, Rina Goto, Kenroh Sasaki
Chemical investigation of the aerial parts of Atraphaxis frutescens resulted in the isolation of five 7-methoxyflavonols with pyrogallol B-ring moieties (1-5), a fisetinidol glucoside (13), and a benzyl glycoside (18), together with 26 known compounds including flavonoids, phenylpropanoid amides, anthraquinone glycosides, lignans, and a benzyl derivative. The principal chemical structural feature of the isolated compounds was either a pyrogallol or catechol B-ring moiety, and they showed potent 1,1-diphenyl-2-picrylhydrazyl radical scavenging activities...
December 23, 2016: Journal of Natural Products
https://www.readbyqxmd.com/read/27995312/prognostic-impact-of-tumour-burden-measured-by-quantitative-real-time-pcr-from-sentinel-lymph-nodes-of-melanoma-patients-data-from-10-year-follow-up
#17
Thomas Kurt Eigentler, Joachim Hinderer, Seema Noor, Claus Garbe, Ulrike Leiter
BACKGROUND: Sentinel node (SN) biopsy is regarded as standard of care for patients (pts) with cutaneous melanoma ≥1.0 mm of thickness. In the recent AJCC classification, findings in the SN are simply classified as positive or negative. In our analyses, we were interested whether quantitative real-time PCR (qRT-PCR) is able to predict disease-free survival (DFS) and overall survival (OS) depending on tumour burden in the SN. METHODS: One hundred and forty-five pts were analysed using qRT-PCR for tyrosinase...
December 19, 2016: Journal of Cancer Research and Clinical Oncology
https://www.readbyqxmd.com/read/27994586/improved-antitumor-activity-of-a-therapeutic-melanoma-vaccine-through-the-use-of-the-dual-cox-2-5-lo-inhibitor-licofelone
#18
Silke Neumann, Simon A Shirley, Roslyn A Kemp, Sarah M Hook
Immune-suppressive cell populations impair antitumor immunity and can contribute to the failure of immune therapeutic approaches. We hypothesized that the non-steroidal anti-inflammatory drug licofelone, a dual cyclooxygenase-2/5-LO inhibitor, would improve therapeutic melanoma vaccination by reducing immune-suppressive cell populations. Therefore, licofelone was administered after tumor implantation, either alone or in combination with a peptide vaccine containing a long tyrosinase-related protein 2-peptide and the adjuvant α-galactosylceramide, all formulated into cationic liposomes...
2016: Frontiers in Immunology
https://www.readbyqxmd.com/read/27988355/agmatine-modulates-melanogenesis-via-mitf-signaling-pathway
#19
Eun-Jeong Kwon, Moon-Moo Kim
Agmatine contained in soybean is also found in Manaca, an anti-aging plant, inhabited in Amazon and induces vasodilation by the promotion of NO synthesis in blood vessel. However, the research of agmatine on melanin synthesis related to hair greying is lacking. The aim of this study was to investigate the melanogenic effect of agmatine via regulation of MITF signaling pathway in B16F1 cells. It was determined whether agmatine regulates melanin synthesis at cellular level in addition to the effect of agmatine on mushroom tyrosinase in vitro in the presence of different concentrations of agmatine...
December 13, 2016: Environmental Toxicology and Pharmacology
https://www.readbyqxmd.com/read/27987057/transcriptome-analysis-of-the-freshwater-pearl-mussel-cristaria-plicata-mantle-unravels-genes-involved-in-the-formation-of-shell-and-pearl
#20
Xuefeng Wang, Zhiming Liu, Wenjian Wu
Cristaria plicata, a bivalve widespread in Eastern Asia fresh water, is utilized as the freshwater pearl mussel in China. With a high economic value in pearl production, it is also an ideal object used for the studies on biomineralization in freshwater. In the research, we performed a large-scale sequencing of Cristaria plicata mantle transcriptome using Illumina HiSeq™ 2500, obtaining 98,501 unigenes with 67,817,724 bases. 22.28 and 16.64% of the unigenes were annotated in the NR and Swiss-Prot databases, respectively...
December 16, 2016: Molecular Genetics and Genomics: MGG
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