Results 61 to 70 of about 9,564 (223)

Solvochromic Effects in Model Eumelanin Compounds^†

Photochemistry and Photobiology, 2008
ABSTRACTWe have created an indolic compound which is ideally suited to the study of the relationship between structure and function in eumelanin formation. N‐methyl‐5‐hydroxy‐6‐methoxyindole (MHMI) is stable in solid and liquid states, highly soluble in a variety of solvents and forms a dimer only through the 4‐4′ positions.
Nighswander-Rempel, Stephen P., Mahadevan, Indumathy B., Bernhardt, Paul V., Butcher, Jessica, Meredith, Paul   +4 more
openaire   +4 more sources

Exploring the optical properties of metal-modified melanin following ultraviolet irradiation: An experimental and theoretical study using density functional theory

Heliyon
Melanin has an important function to protect humans from sunlight because of its broad spectrum of light absorption. This characteristic varies according to the nature of absorption and the amount of melanin manufactured.
Nawal Madkhali, Saja Algessair
doaj   +1 more source

In Vivo and In Vitro Evaluation of PTeCA (1H‐Pyrrole‐2,3,4,5‐Tetracarboxylic Acid) in Hair Matrix as a Marker for Oxidative Cosmetic Treatment

Drug Testing and Analysis, EarlyView.
A total of 3378 self‐reported treated and untreated hair samples were analyzed for PTCA and PTeCA by LC‐MS/MS. Moreover, their in vitro formation was assessed in 225 untreated hair by different cosmetic treatments with and without oxidative agents. Data suggest that PTeCA could be a reliable marker for oxidative cosmetic treatments in hair.
Sara Casati, Alessandro Ravelli, Roberta F. Bergamaschi, Agata Magliocco, Sofia Vanerio, Gabriella Roda, Paola Rota, Marica Orioli, Alessio Battistini   +8 more
wiley   +1 more source

Redox activity of melanin from the ink sac of Sepia officinalis by means of colorimetric oxidative assay [PDF]

, 2015
The redox properties of natural extract from cuttlefish ink sac (Sepia officinalis) and synthetic melanin used as a biomimetic in melanin structural investigation were determined by comparison of this phenol-based heterogeneous pigment with gallic acid ...
Correlo, V. M., Leonor, I. B., Palladino, Pasquale, Reis, R. L., Srisuk, Pathomthat   +4 more
core   +1 more source

Segmental Hair Analysis of Diphenhydramine and Cyclizine Following a Single Dose

Drug Testing and Analysis, EarlyView.
A single oral dose of diphenhydramine and cyclizine can be quantified in human head hair for a minimum of 5 months and, in certain cases, for up to 1 year following intake. Among 12 study participants, the measured concentrations ranged from 0 to 610 pg/mg within 1 year post‐intake.
Jan Bílek, Marie Katrine Klose Nielsen, Robert Kronstrand, Sys Stybe Johansen   +3 more
wiley   +1 more source

Aspacochioside C from Asparagus cochinchinensis attenuates eumelanin synthesis via inhibition of TRP2 expression

Scientific Reports, 2023
Aspacochioside C (ACC) is a steroidal saponin isolated from Asparagus cochinchinensis. Steroidal saponins, such as pseudoprotodioscin and dioscin, are known to inhibit melanogenesis, but the role of ACC in melanogenesis remains unknown.
Silvia Yunmam, Hae Ran Lee, Seong Min Hong, Ji-Young Kim, Tong Ho Kang, Ai Young Lee, Dae Sik Jang, Sun Yeou Kim   +7 more
doaj   +1 more source

Alpha‐Synuclein Promotes Anterograde Vesicle Transport in Melanocytes and Melanoma Cells: A Pro‐Survival Function

Journal of the Chinese Chemical Society, EarlyView.
Model for how α‐syn modulates the positioning of endolysosomes in melanoma cells. (a) α‐syn tethers endolysosomes to the plasma membrane, a last step in anterograde transport. (b) Loss of α‐syn expression causes the loss of the tethering function, which leads to perinuclear vesicle clustering. Reproduced from the open access article.
Stephan N. Witt
wiley   +1 more source

Fundamental building blocks of eumelanins: electronic properties of indolequinone-dimers

, 2003
We present results from the theoretical INDO calculations of the electronic structure for stacked eumelanins' monomers. As basic indolic components of the eumelanin structure 5,6-dihydroxyindole (DHI or HQ) and its oxidized forms (SQ and IQ) were chosen.
Bochenek, Bolivar-Marinez, Cheng, Clancy, Ewa Gudowska-Nowak, Galvão, Galvão, Kinga Bochenek, Prota, Prota, Pullman, Ridley, Rosei, Sarna, Young, Zajac, Zhang   +16 more
core   +1 more source

Signatures of pancake bonding in hydrated eumelanin

Physical Chemistry Chemical Physics, 2023
Pancake bonding phenomenology explains the long-term inconsistency between electron paramagnetic resonance, muon spin relaxation and conductivity data for biopigment eumelanin.
P. A. Abramov, O. I. Ivankov, A. B. Mostert, K. A. Motovilov   +3 more
openaire   +4 more sources

En Route to a Chiral Melanin: The Dynamic “From-Imprinted-to-Template” Supramolecular Role of Porphyrin Hetero-Aggregates During the Oxidative Polymerization of L-DOPA

Frontiers in Chemistry, 2020
Chiral porphyrin hetero-aggregates, produced from meso-tetrakis(4-N-methylpyridyl) porphyrin H2T4 and copper(II) meso-tetrakis(4-sulfonatophenyl)porphyrin CuTPPS by an imprinting effect in the presence of L-3,4-dihydroxyphenylalanine (L-DOPA), are shown ...
Massimiliano Gaeta, Rosalba Randazzo, Valentina Villari, Norberto Micali, Alessandro Pezzella, Roberto Purrello, Marco d'Ischia, Alessandro D'Urso   +7 more
doaj   +1 more source