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Tyrosinase

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https://www.readbyqxmd.com/read/28228229/oxidative-transformation-of-a-tunichrome-model-compound-provides-new-insight-into-the-crosslinking-and-defense-reaction-of-tunichromes
#1
Adal Abebe, Qun F Kuang, Jason Evans, William E Robinson, Manickam Sugumaran
Tunichromes, small oligopeptides with dehydrodopa units isolated from the blood cells of ascidians, have been implicated in the defense reactions, metal binding, wound repair, or tunic formation. Their instability and high reactivity has severely hampered the assessment of their biological role. Experiments conducted with the model compound, 1,2-dehydro-N-acetyldopamine, indicated that the instability of tunichromes is due to this basic structure. Exposure of this catecholamine derivative to even mild alkaline condition such as pH 7...
February 16, 2017: Bioorganic Chemistry
https://www.readbyqxmd.com/read/28219012/the-tyrosinase-catalyzed-oxidation-of-the-leukoderma-inducing-agent-raspberry-ketone-produces-e-4-3-oxo-1-butenyl-1-2-benzoquinone-implications-for-melanocyte-toxicity
#2
Shosuke Ito, Maki Hinoshita, Erina Suzuki, Makoto Ojika, Kazumasa Wakamatsu
The exposure of human skin to 4-(4-hydroxyphenyl)-2-butanone (raspberry ketone, RK) is known to cause chemical/occupational leukoderma. RK has a structure closely related to 4-(4-hydroxyphenyl)-2-butanol (rhododendrol), a skin whitening agent that was found to cause leukoderma in the skin of consumers in 2013. Rhododendrol is a good substrate for tyrosinase and causes a tyrosinase-dependent cytotoxicity to melanocytes, cells that are responsible for skin pigmentation. Therefore, it is expected that RK exerts its cytotoxicity to melanocytes through the tyrosinase-catalyzed oxidation to cytotoxic o-quinones...
February 20, 2017: Chemical Research in Toxicology
https://www.readbyqxmd.com/read/28217548/polygonum-multiflorum-root-extract-as-a-potential-candidate-for-treatment-of-early-graying-hair
#3
Nguyen Dinh Thang, Pham Ngoc Diep, Pham Thi Huong Lien, Le Thi Lien
Despite Polygonum multiflorum (PM) has been experiencely used as a drug to treat early graying hair phenomenon in Asian countries for a long time, there is limited study examined the real biological effects of PM on hair graying in vitro and in vivo. In this study, we investigated the effects of PM root extract (PM-RE) on melanin synthesis in human melanoma SKMEL-28 cells and embryos/larvae of wild-type strain AB zebrafish. We also preliminary revealed the molecular mechanism of early hair graying phenomenon in both in vitro and in vivo models...
January 2017: Journal of Advanced Pharmaceutical Technology & Research
https://www.readbyqxmd.com/read/28208818/hydroxycinnamic-acids-and-their-derivatives-cosmeceutical-significance-challenges-and-future-perspectives-a-review
#4
Oludemi Taofiq, Ana M González-Paramás, Maria Filomena Barreiro, Isabel C F R Ferreira
Bioactive compounds from natural sources, due to their widely-recognized benefits, have been exploited as cosmeceutical ingredients. Among them, phenolic acids emerge with a very interesting potential. In this context, this review analyzes hydroxycinnamic acids and their derivatives as multifunctional ingredients for topical application, as well as the limitations associated with their use in cosmetic formulations. Hydroxycinnamic acids and their derivatives display antioxidant, anti-collagenase, anti-inflammatory, antimicrobial and anti-tyrosinase activities, as well as ultraviolet (UV) protective effects, suggesting that they can be exploited as anti-aging and anti-inflammatory agents, preservatives and hyperpigmentation-correcting ingredients...
February 13, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28204812/the-lactoferricin-b-derived-peptide-lfb17-34-induces-melanogenesis-in-b16f10-cells
#5
Hsiu-Chin Huang, Hsuan Lin, Min-Chuan Huang
Lactoferricin B (LfcinB), a peptide of bovine lactoferrin (LfB), exhibits multiple biological functions, including antimicrobial, antiviral, antioxidant and immunomodulatory activities. However, the role of LfcinB-related peptides in melanogenesis remains unclear. In this study, a set of five LfcinB-related peptides was examined. We found that LfB17‑34, an 18-mer LfcinB-derived peptide, increased melanogenesis in B16F10 melanoma cells without significantly affecting cell viability. LfB17‑34 increased in vitro tyrosinase activity and melanin content in a dose-dependent manner...
March 2017: International Journal of Molecular Medicine
https://www.readbyqxmd.com/read/28195739/substrate-and-lewis-acid-coordination-promote-o-o-bond-cleavage-of-an-unreactive-l2cu-ii-2-o2-2-species-to-form-l2cu-iii-2-o-2-cores-with-enhanced-oxidative-reactivity
#6
Isaac Garcia-Bosch, Ryan E Cowley, Daniel E Díaz, Ryan L Peterson, Edward I Solomon, Kenneth D Karlin
Copper-dependent metalloenzymes are widespread throughout metabolic pathways, coupling the reduction of O2 with the oxidation of organic substrates. Small-molecule synthetic analogs are useful platforms to generate L/Cu/O2 species that reproduce the structural, spectroscopic, and reactive properties of some copper-/O2-dependent enzymes. Landmark studies have shown that the conversion between dicopper(II)-peroxo species (L2Cu(II)2(O2(2-)) either side-on peroxo, (S)P, or end-on trans-peroxo, (T)P) and dicopper(III)-bis(μ-oxo) (L2Cu(III)2(O(2-))2: O) can be controlled through ligand design, reaction conditions (temperature, solvent, and counteranion), or substrate coordination...
February 14, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28195138/bioproduction-characterization-anticancer-and-antioxidant-activities-of-extracellular-melanin-pigment-produced-by-newly-isolated-microbial-cell-factories-streptomyces-glaucescens-neae-h
#7
Noura El-Ahmady El-Naggar, Sara M El-Ewasy
In this present study, a newly isolated strain, Streptomyces sp. NEAE-H, capable of producing high amount of black extracellular melanin pigment on peptone-yeast extract iron agar and identified as Streptomyces glaucescens NEAE-H. Plackett-Burman statistical design was conducted for initial screening of 17 independent (assigned) variables for their significances on melanin pigment production by Streptomyces glaucescens NEAE-H. The most significant factors affecting melanin production are incubation period, protease-peptone and ferric ammonium citrate...
February 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28192773/a-bioinspired-elastin-based-protein-for-a-cytocompatible-underwater-adhesive
#8
M Jane Brennan, Bridget F Kilbride, Jonathan J Wilker, Julie C Liu
The development of adhesives that can be applied and create strong bonds underwater is a significant challenge for materials engineering. When the adhesive is intended for biomedical applications, further criteria, such as biocompatibility, must be met. Current biomedical adhesive technologies do not meet these needs. In response, we designed a bioinspired protein system that shows promise to achieve biocompatible underwater adhesion coupled with environmentally responsive behavior that is "smart" - that is, it can be tuned to suit a specific application...
January 30, 2017: Biomaterials
https://www.readbyqxmd.com/read/28192140/action-of-2-2-4-4-tetrahydroxybenzophenone-in-the-biosynthesis-pathway-of-melanin
#9
Antonio Garcia-Jimenez, Jose Antonio Teruel-Puche, Pedro Antonio Garcia-Ruiz, Jose Berna, Jose Neptuno Rodríguez-López, Jose Tudela, Francisco Garcia-Canovas
2,2',4,4'-tetrahydroxybenzophenone (Uvinul D50), a sunscreen used in cosmetics, has two effects in the melanin biosynthesis pathway. On the one hand, it acts a weak inhibitor of tyrosinase and on the other, it accelerates the conversion of dopachrome to melanin. Uvinul D50 was seen to behave as a weak competitive inhibitor: apparent constant inhibition=2.02±0.09mM and IC50=3.82±0.39mM established in this work. These values are higher than those in the bibliography, which tend to be undersetimated. This discrepancy could be explained by the reaction of Uvinul D50 with the dopachrome produced from l-tyrosine or l-dopa, which would interfere in the measurement...
February 10, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28188783/disruption-of-melanosome-transport-in-melanocytes-treated-with-theophylline-causes-their-degradation-by-autophagy
#10
Yushi Katsuyama, Norihisa Taira, Masato Yoshioka, Yuri Okano, Hitoshi Masaki
Melanosomes containing melanin are transported from the perinuclear area to the tips of dendrites in epidermal melanocytes, and are then transferred to keratinocytes. Thus, skin color is determined by the amount of melanin synthesized in melanocytes and the subsequent dispersion of melanosomes in the epidermis. Therefore, disrupting intracellular melanosome transport in melanocytes is considered an effective approach to regulate skin color. However, the fate of melanosomes that accumulate in melanocytes due to disrupted intracellular transport is unclear...
February 7, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28185012/the-synergistic-effect-of-maltose-enhances-the-anti-melanogenic-activity-of-acarbose
#11
Bum-Ho Bin, Sung Tae Kim, Jinhyuk Bhin, Kyounghee Byoun, Tae Ryong Lee, Eun-Gyung Cho
Melanocytes play an important role in maintaining epidermal homeostasis by producing melanin and protecting the skin from harmful environmental factors. However, excessive up- or down-regulation of melanin production often causes hyper- or hypo-pigmented disorders, respectively, which affect the patient's quality of life. Therefore, various strategies for modulating melanin levels have been developed by the pharmaceutical and cosmetic industries. We reported previously that voglibose, which is a well-known anti-hyperglycemic agent, could be used as an anti-melanogenic agent by inhibiting α-glucosidase activity and reducing tyrosinase protein levels...
February 9, 2017: Archives of Dermatological Research
https://www.readbyqxmd.com/read/28183263/aryl-butenes-active-against-k562-cells-and-lacking-tyrosinase-inhibitory-activity-as-new-leads-in-the-treatment-of-leukemia
#12
Mehdi El Arbi, Emna Ketata, Aref Neifar, Wafa Mihoubi, Girish K Gupta, Pascal Pigeon, Siden Top, Ali Gargouri, Gérard Jaouen
The inhibitory effects of four series of aryl butene derivatives, active against breast cancer, on the monophenolase activity of tyrosinase, in melanin-free ink from Sepia officinalis, have been studied. Hydroxytamoxifen 1, ferrociphenol 17 and several aryl butene analogs have shown strong antiproliferative activity on hormone-dependent and hormone-independent breast cancer cells and were evaluated in leukemia K562 cell proliferation. Their potential to induce skin depigmentation by evaluating their anti-tyrosinase activity was also estimated...
February 8, 2017: Mini Reviews in Medicinal Chemistry
https://www.readbyqxmd.com/read/28182699/bifunctional-effects-of-o-methylated-flavones-from-scutellaria-baicalensis-georgi-on-melanocytes-inhibition-of-melanin-production-and-intracellular-melanosome-transport
#13
Michiko Kudo, Kumiko Kobayashi-Nakamura, Kentaro Tsuji-Naito
The growing interest in skin lightening has recently renewed attention on the esthetic applications of Chinese herbal medicine. Although Scutellaria baicalensis Georgi is used for antipyretic and antiinflammatory purposes, its whitening effect remains unclear. This study reports three major findings: (1) S. baicalensis has a potent inhibitory effect on melanogenesis; (2) wogonin and its glycoside are the active components of S. baicalensis; and (3) O-methylated flavones from S. baicalensis, such as wogonin, inhibit intracellular melanosome transport...
2017: PloS One
https://www.readbyqxmd.com/read/28174780/shedding-light-on-the-biological-and-chemical-fingerprints-of-three-achillea-species-a-biebersteinii-a-millefolium-and-a-teretifolia
#14
Gokhan Zengin, Abdurrahman Aktumsek, Ramazan Ceylan, Sengul Uysal, Andrei Mocan, Gokalp Ozmen Guler, M Fawzi Mahomoodally, Jasmina Glamočlija, Ana Ćirić, Marina Soković
Representatives of the Achillea genus are widely used as foods or nutraceuticals. Considering the increasing demand for herbal dietary supplements with health promoting effects, the objective of this research was to evaluate the biological and chemical profiles of different extracts (ethyl acetate, methanol and water) obtained from three Achillea species (A. biebersteinii, A. millefolium and A. teretifolia). The antioxidant (free radical scavenging (DPPH and ABTS), reducing power (CUPRAC and FRAP), metal chelating and phosphomolybdenum), enzyme inhibitory (anti-cholinesterase, anti-tyrosinase, anti-amylase and anti-glucosidase) and antimicrobial (antibacterial and antifungal) effects were assessed to investigate their biological profiles...
February 8, 2017: Food & Function
https://www.readbyqxmd.com/read/28174769/a-highly-sensitive-and-selective-fluorescence-off-on-probe-for-the-detection-of-intracellular-endogenous-tyrosinase-activity
#15
Xiaofeng Wu, Xiaohua Li, Hongyu Li, Wen Shi, Huimin Ma
A resorufin-based highly sensitive and selective fluorescence off-on probe with a new recognition moiety for tyrosinase is developed, and applied to detect and image endogenous tyrosinase activity in different living cells.
February 8, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28168765/prediction-of-anti-alzheimer-s-activity-of-flavonoids-targeting-acetylcholinesterase-in-silico
#16
Subrata Das, Monjur A Laskar, Satyajit D Sarker, Manabendra D Choudhury, Prakash Roy Choudhury, Abhijit Mitra, Shajarahtunnur Jamil, Siti Mariam A Lathiff, Siti Awanis Abdullah, Norazah Basar, Lutfun Nahar, Anupam D Talukdar
INTRODUCTION: Prenylated and pyrano-flavonoids of the genus Artocarpus J. R. Forster & G. Forster are well known for their acetylcholinesterase (AChE) inhibitory, anti-cholinergic, anti-inflammatory, anti-microbial, anti-oxidant, anti-proliferative and tyrosinase inhibitory activities. Some of these compounds have also been shown to be effective against Alzheimer's disease. OBJECTIVE: The aim of the in silico study was to establish protocols to predict the most effective flavonoid from prenylated and pyrano-flavonoid classes for AChE inhibition linking to the potential treatment of Alzheimer's disease...
February 7, 2017: Phytochemical Analysis: PCA
https://www.readbyqxmd.com/read/28165370/plumbagin-suppresses-%C3%AE-msh-induced-melanogenesis-in-b16f10-mouse-melanoma-cells-by-inhibiting-tyrosinase-activity
#17
Taek-In Oh, Jeong-Mi Yun, Eun-Ji Park, Young-Seon Kim, Yoon-Mi Lee, Ji-Hong Lim
Recent studies have shown that plumbagin has anti-inflammatory, anti-allergic, antibacterial, and anti-cancer activities; however, it has not yet been shown whether plumbagin suppresses alpha-melanocyte stimulating hormone (α-MSH)-induced melanin synthesis to prevent hyperpigmentation. In this study, we demonstrated that plumbagin significantly suppresses α-MSH-stimulated melanin synthesis in B16F10 mouse melanoma cells. To understand the inhibitory mechanism of plumbagin on melanin synthesis, we performed cellular or cell-free tyrosinase activity assays and analyzed melanogenesis-related gene expression...
February 3, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28165285/lactoferrin-inhibits-melanogenesis-by-down-regulating-mitf-in-melanoma-cells-and-normal-melanocytes
#18
Nanase Ishii, Mizuyuki Ryu, Yasushi A Suzuki
The aim of this study was to evaluate the effect of bovine lactoferrin (bLf) on melanin-producing cells and to elucidate its mechanism of action. We tested the anti-melanogenic effect of bLf on a 3-dimensional cultured pigmentation skin model and confirmed a 20% reduction in pigmentation, suggesting that bLf was transdermally absorbed and it suppressed melanin production. Treatment of human melanoma cells with bLf resulted in a significant, dose-dependent suppression of melanin production. Apo-bLf and holo-bLf suppressed melanogenesis to the same degree as bLf...
February 2017: Biochemistry and Cell Biology, Biochimie et Biologie Cellulaire
https://www.readbyqxmd.com/read/28163970/garcinia-subelliptica-merr-fukugi-a-multipurpose-coastal-tree-with-promising-medicinal-properties
#19
REVIEW
Tomomi Inoue, Mami Kainuma, Karin Baba, Nozomi Oshiro, Norimi Kimura, Eric Wei Chiang Chan
In this short review, the current knowledge on the botany, ecology, uses, and medicinal properties of the multipurpose Garcinia subelliptica (Fukugi) is updated. As yet, there are no reviews on this indigenous and heritage coastal tree species of the Ryukyu Islands in Japan, which has ethnocultural, ecological, and pharmacological significance. Planted by the Okinawan people some 300 years ago, Fukugi trees serve as windbreaks and accord protection against the destructive typhoons. The species has become a popular ornamental tree, and its bark has been used for dyeing fabrics...
January 2017: Journal of Intercultural Ethnopharmacology
https://www.readbyqxmd.com/read/28161548/anti-melasma-codrug-of-retinoic-acid-assists-cutaneous-absorption-with-attenuated-skin-irritation
#20
Pei-Wen Hsieh, Chi-Feng Hung, Chih-Hung Lin, Chang-Wei Huang, Jia-You Fang
Melasma treatment with combined retinoic acid (RA) and hydroquinone (HQ) usually causes unsatisfactory outcomes and safety concerns. This study attempted to evaluate the cutaneous absorption and skin tolerance of the codrug conjugated with RA and HQ via ester linkage. The codrug's permeation of the pig skin was estimated using Franz diffusion cell. The codrug and parent drugs were comparatively examined for anti-inflammatory activity and tyrosinase inhibition. In vivo cutaneous irritation was assessed on nude mouse skin...
February 1, 2017: European Journal of Pharmaceutics and Biopharmaceutics
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