A5030585327- melanin and skin pigmentation
- Phytochemicals and Antioxidant Activities
- Biochemical Analysis and Sensing Techniques
- Skin Protection and Aging
- Free Radicals and Antioxidants
- Olfactory and Sensory Function Studies
- Antioxidant Activity and Oxidative Stress
- biodegradable polymer synthesis and properties
- Nanocomposite Films for Food Packaging
- Photochromic and Fluorescence Chemistry
- Pomegranate: compositions and health benefits
- Lignin and Wood Chemistry
- Polymer Surface Interaction Studies
- Biochemical and biochemical processes
- Bioactive Compounds and Antitumor Agents
- Coffee research and impacts
- Dyeing and Modifying Textile Fibers
- Ginkgo biloba and Cashew Applications
- Tea Polyphenols and Effects
- Sesame and Sesamin Research
- Radical Photochemical Reactions
- Edible Oils Quality and Analysis
- Sulfur Compounds in Biology
- Nitric Oxide and Endothelin Effects
- Conducting polymers and applications
University of Naples Federico II
2015-2024
Naples Anesthesia & Physician Associates
2015-2018
University of Florence
2015
Universidade Federal de Alfenas
2014
Daresbury Laboratory
2006-2009
University of Salford
2006-2009
Lund University
2008-2009
University of Manchester
2009
Keele University
2006-2009
Istituto di Chimica Biomolecolare
2009
The black we wear: Why nature selected 5,6-dihydroxyindole-2-carboxylic acid (DHICA) to synthesize (photo)protective eumelanin pigments is an enigma. Synthetic DHICA has now been shown be a highly efficient free-radical scavenger in the solid state, which due conformationally interrupted π-electron network associated with atypical optical, paramagnetic, and aggregation properties.
One of the most common approaches for control skin pigmentation involves inhibition tyrosinase, a copper-containing enzyme which catalyzes key steps melanogenesis. This review focuses on tyrosinase properties series natural and synthetic, bioinspired phenolic compounds that have appeared in literature last five years. Both mushroom human inhibitors been considered. Among first class, flavonoids, particular chalcones, occupy prominent role as inhibitors, followed by hydroxystilbenes (mainly...
A fundamental unsettled issue concerning eumelanins, the functional biopolymers of human skin and hair, is why they are black. The experimental difficulty lies in virtual insolubility these pigments, causing marked scattering effects hindering characterization intrinsic absorption properties heterogeneous species produced by oxidative polymerization 5,6-dihydroxyindole (DHI) related monomer precursors. synthesis spectrally robust, water-soluble DHI polymers therefore an important goal...
The role of 5,6-dihydroxyindole (DHI)-based oligomers, including porphyrin-like tetramers, in polydopamine (PDA) film formation was addressed by a comparative structural investigation against model polymers from DHI and its 2,7′-dimer. MALDI-MS data showed that (a) PDA is structurally different melanin does not contain species compatible with DHI-based oligomers as primary building blocks; (b) films precipitate display single main peak at m/z 402 common; (c) no matching the range values...
Summary The highest incidence of melanoma in red haired individuals is attributed to the synthesis and phototoxic properties pheomelanin pigments. Recently, has also been implicated UV ‐independent pathways oxidative stress; however, underlying mechanisms have remained uncharted. Herein, we disclose unprecedented property purified human hair ( RHP ) promote (i) oxygen‐dependent depletion major cell antioxidants, for example glutathione NADH ; (ii) autoxidative formation melanin pigments from...
Despite extensive investigations over the past decade, chemical basis of extraordinary underwater adhesion properties polydopamine (PDA) has remained not entirely understood. The bulk evidence points to PDA wet as a complex process based on film deposition, and growth in which primary amine groups, besides catechol moieties, play central role. However, detailed interplay interactions underlying dynamics formation yet been elucidated. Herein, we report results series experiments showing that...
Eumelanins, the chief photoprotective pigments in man and mammals, owe their black color to an unusual broadband absorption spectrum whose origin is still a conundrum. Excitonic effects from interplay of geometric order disorder 5,6-dihydroxyindole (DHI)-based oligomeric/polymeric structures play central role, however contributions structural (scaffold-controlled) redox (π-electron-controlled) have remained uncharted. Herein, we report integrated experimental-theoretical entry eumelanin...
Polyphenols are natural organic compounds with many possible applications because of their unique biological activities. They can be extracted from a wide variety waste biomasses, and great deal interest exists in identifying extraction processes optimized terms both yield environmental impact. In this framework, we have compared three techniques, namely, maceration assisted by either ultrasounds or microwaves, for the phenolic dry pine needles, largely available underexploited biomass. The...
The transient species formed by oxidation of three dimers 5,6-dihydroxyindole (1), a major building block the natural biopolymer eumelanin, have been investigated. Pulse radiolytic 5,5',6,6'-tetrahydroxy-2,4'-biindolyl (3) and 5,5',6,6'-tetrahydroxy-2,7'-biindolyl (4) led to semiquinones absorbing around 450 nm, which decayed with second-order kinetics (2k=2.8x10(9) 1.4x10(9) M-1 s-1, respectively) give corresponding quinones (500-550 nm). 5,5',6, 6'-Tetrahydroxy-2,2'-biindolyl (2), on other...
Chemical or enzymatic oxidation of 5,6-dihydroxyindole (1) leads to the rapid deposition a black solid resembling eumelanin pigments by way complex oligomerization/polymerization process that proceeds in early stages via dimers 2−3 and trimers 5−6 characterized 2,4'- 2,7'-couplings. Despite extensive efforts, structures higher oligomers, which define structural architecture physicochemical properties particles, have so far defied elucidation. Using dimer−dimer coupling strategy has recently...
Summary A pulse radiolytic investigation has been conducted to establish whether a redox reaction takes place between dopaquinone and 5,6‐dihydroxyindole (DHI) its 2‐carboxylic acid (DHICA) measure the rate constants of interactions. To obviate possible confounding reactions, such as nucleophilic addition, method employed generate used dibromide radical anion acting on dopa form semiquinone which rapidly disproportionates dopaquinone. In presence DHI corresponding indole‐5,6‐quinone (and/or...
The first tetramer of the eumelanin precursor 5,6-dihydroxyindole has been obtained, as acetyl derivative, by peroxidase/H2O2-induced oxidative coupling 5,5',6,6'-tetrahydroxy-2,4'-biindolyl (2) in presence Zn2+ ions. tetramer, 5,5',5' ',5' '',6,6',6' ',6' ''-octaacetoxy-2,4':2',3' ':2' ',4' ''-tetraindolyl (acetylated 7), incorporates an unprecedented 2,3'-biindolyl substructure suggestive a different positional reactivity system when framed into dimeric scaffold.