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1.
Molecules ; 26(4)2021 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-33668684

RESUMO

The disposal of food waste is a current and pressing issue, urging novel solutions to implement sustainable waste management practices. Fish leftovers and their processing byproducts represent a significant portion of the original fish, and their disposal has a high environmental and economic impact. The utilization of waste as raw materials for the production of different classes of biofuels and high-value chemicals, a concept known as "biorefinery", is gaining interest in a vision of circular economy and zero waste policies. In this context, an interesting route of valorization is the extraction of omega-3 fatty acids (ω-3 FAs) for nutraceutical application. These fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have received attention over the last decades due to their beneficial effects on human health. Their sustainable production is a key process for matching the increased market demand while reducing the pressure on marine ecosystems and lowering the impact of waste production. The high resale value of the products makes this waste a powerful tool that simultaneously protects the environment and benefits the global economy. This review aims to provide a complete overview of the sustainable exploitation of fish waste to recover ω-3 FAs for food supplement applications, covering composition, storage, and processing of the raw material.


Assuntos
Suplementos Nutricionais , Ácidos Graxos Ômega-3/farmacologia , Peixes/metabolismo , Alimentos , Desenvolvimento Sustentável , Resíduos/análise , Animais , Ácidos Graxos Ômega-3/química , Óleos de Peixe/química , Óleos de Peixe/isolamento & purificação , Óleos de Peixe/farmacologia
2.
Int J Mol Sci ; 19(8)2018 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-30042336

RESUMO

Caffeic acid derivatives represent promising lead compounds in the search for tyrosinase inhibitors to be used in the treatment of skin local hyperpigmentation associated to an overproduction or accumulation of melanin. We recently reported the marked inhibitory activity of a conjugate of caffeic acid with dihydrolipoic acid, 2-S-lipoylcaffeic acid (LCA), on the tyrosine hydroxylase (TH) and dopa oxidase (DO) activities of mushroom tyrosinase. In the present study, we evaluated a more lipophilic derivative, 2-S-lipoyl caffeic acid methyl ester (LCAME), as an inhibitor of tyrosinase from human melanoma cells. Preliminary analysis of the effects of LCAME on mushroom tyrosinase indicated more potent inhibitory effects on either enzyme activities (IC50 = 0.05 ± 0.01 µM for DO and 0.83 ± 0.09 µM for TH) compared with LCA and the reference compound kojic acid. The inhibition of DO of human tyrosinase was effective (Ki = 34.7 ± 1.1 µM) as well, while the action on TH was weaker. Lineweaver⁻Burk analyses indicated a competitive inhibitor mechanism. LCAME was not substrate of tyrosinase and proved nontoxic at concentrations up to 50 µM. No alteration of basal tyrosinase expression was observed after 24 h treatment of human melanoma cells with the inhibitor, but preliminary evidence suggested LCAME might impair the induction of tyrosinase expression in cells stimulated with α-melanocyte-stimulating hormone. All these data point to this compound as a valuable candidate for further trials toward its use as a skin depigmenting agent. They also highlight the differential effects of tyrosinase inhibitors on the human and mushroom enzymes.


Assuntos
Ácidos Cafeicos/química , Inibidores Enzimáticos/farmacologia , Monofenol Mono-Oxigenase/antagonistas & inibidores , Preparações Clareadoras de Pele/farmacologia , Ácido Tióctico/análogos & derivados , Agaricales/enzimologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/química , Humanos , Concentração Inibidora 50 , Melaninas/metabolismo , Melanoma/enzimologia , Pironas/farmacologia , Preparações Clareadoras de Pele/química , Ácido Tióctico/química , Tirosina 3-Mono-Oxigenase/antagonistas & inibidores
3.
Int J Mol Sci ; 17(5)2016 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-27196900

RESUMO

Recent advances in the chemistry of melanins have begun to disclose a number of important structure-property-function relationships of crucial relevance to the biological role of human pigments, including skin (photo) protection and UV-susceptibility. Even slight variations in the monomer composition of black eumelanins and red pheomelanins have been shown to determine significant differences in light absorption, antioxidant, paramagnetic and redox behavior, particle morphology, surface properties, metal chelation and resistance to photo-oxidative wear-and-tear. These variations are primarily governed by the extent of decarboxylation at critical branching points of the eumelanin and pheomelanin pathways, namely the rearrangement of dopachrome to 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA), and the rearrangement of 5-S-cysteinyldopa o-quinoneimine to 1,4-benzothiazine (BTZ) and its 3-carboxylic acid (BTZCA). In eumelanins, the DHICA-to-DHI ratio markedly affects the overall antioxidant and paramagnetic properties of the resulting pigments. In particular, a higher content in DHICA decreases visible light absorption and paramagnetic response relative to DHI-based melanins, but markedly enhances antioxidant properties. In pheomelanins, likewise, BTZCA-related units, prevalently formed in the presence of zinc ions, appear to confer pronounced visible and ultraviolet A (UVA) absorption features, accounting for light-dependent reactive oxygen species (ROS) production, whereas non-carboxylated benzothiazine intermediates seem to be more effective in inducing ROS production by redox cycling mechanisms in the dark. The possible biological and functional significance of carboxyl retention in the eumelanin and pheomelanin pathways is discussed.


Assuntos
Ácidos Carboxílicos/química , Melaninas/química , Antioxidantes/química , Vias Biossintéticas , Humanos , Fenômenos Magnéticos
7.
G Ital Dermatol Venereol ; 155(3): 286-293, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29192469

RESUMO

BACKGROUND: Natural antioxidants represent an effective option in the prevention and/or improvement of ultraviolet radiations (UVR)-induced/aggravated skin conditions. UVR cause DNA damage in keratinocytes, directly, in the form of cyclobutane pyrimidine dimers (CPDs), or indirectly, through oxidative stress production. Failure of the repair system can result in genetic mutations primarily responsible for the initiation of NMSCs. The aim of our study was to evaluate the in vitro protective effect of milk thistle and olive purified extracts on cultured keratinocytes after solar simulator irradiations (SSR). METHODS: Immortalized keratinocytes were pre-incubated with different concentrations of milk thistle and olive purified extracts, and irradiated with increasing doses of SSR. Thereafter, CPDs and p53 expression were evaluated to assess DNA damage, whereas cellular antioxidants consumption and lipid membranes peroxidation were measured to analyze oxidative stress. RESULTS: The study substances were well tolerated by cells and displayed good cytoprotective and antioxidant activities, being milk thistle dry extract more effective in limiting the direct DNA damage, and olive extract particularly able to reduce lipid membrane peroxidation and to increase cellular antioxidants. CONCLUSIONS: Both study substances can be defined as safe compounds, showing differential cytoprotective and antioxidant activities and might represent interesting options for NMSCs chemoprevention.


Assuntos
Produtos Biológicos/farmacologia , Queratinócitos/efeitos dos fármacos , Extratos Vegetais/farmacologia , Silybum marianum/química , Antioxidantes/administração & dosagem , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Produtos Biológicos/administração & dosagem , Dano ao DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Células HaCaT , Humanos , Queratinócitos/patologia , Peroxidação de Lipídeos/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/administração & dosagem , Raios Ultravioleta/efeitos adversos
8.
ACS Sustain Chem Eng ; 8(17): 6700-6712, 2020 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-33828928

RESUMO

Herein, the antioxidant and food stabilizing properties of a pecan nut shell (PNS) hydroalcoholic extract (PNSE) are reported. Chemical degradation of PNSE demonstrated the presence of condensed tannins as the main phenolic components. PNSE showed remarkable antioxidant properties in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay (EC50 = 0.004 mg/mL). PNSE was initially tested as an inhibitor of mushroom tyrosinase, exhibiting a quite low IC50 value (0.055 mg/mL) against the enzyme diphenolase activity, suggesting its use in enzymatic browning inhibition. The anthocyanin stabilization properties were evaluated under accelerated aging conditions of both pure pigments and commercial fruit juices, and PNSE was found to be effective at concentrations (0.05 mg/mL) at which well-known stabilizers such as chlorogenic and ferulic acids proved to fail. PNSE also performed well in the stabilization of spray-dried anthocyanins for use as a food colorant, increasing the half-life of blackberry anthocyanins up to 20%. In order to explore the possibility of using PNSE as a functional additive for active packaging, polylactic acid (PLA) films containing PNSE were prepared by solvent casting, and no substantial alteration of the mechanical properties was found on addition of the extract up to 10% w/w. The films showed remarkable antioxidant properties (DDPH reduction >60% with a 3% w/w loading, at a dose of 1 mg/mL in the DPPH solution) and delayed the onset of browning of apple smoothies (ca. 30% inhibition with a 10% w/w loading). These results highlight the exploitation of PNS as a low-cost polyphenol source for food industry applications.

9.
G Ital Dermatol Venereol ; 154(6): 624-631, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28712268

RESUMO

BACKGROUND: 1,2-Decanediol (S-Mal) is an organic compound belonging to the 1,2-alkanediol family, with two hydroxyl groups located on the first and second carbon of the alkane chain, probably responsible for the enhanced anti-bacterial efficacy. The willow bark total extract (W-Mal) has been used since thousands of years as an herbal remedy for its antipyretic, analgesic, anti-inflammatory and anti-microbial activities. S-Mal is used in cosmetic preparations, whether W-Mal can be topically or systemically administered. Aim of our study was to evaluate in vitro the anti-inflammatory and antioxidant properties of S-Mal and W-Mal, singularly or in combination, in LPS-stimulated keratinocytes. METHODS: The possible toxic effect of S-Mal and W-Mal was assessed through analysis of cell viability 24 hours after treatment. The anti-inflammatory and antioxidant activities were evaluated by measuring IL-8, TNF-α and IL-1ß production as well as cellular antioxidants (GSH and NADPH) consumption, 24 and 48 hours, respectively, after LPS stimulation. RESULTS: Both substances resulted able to: 1) increase cell viability (P<0.05); 2) decrease the release of inflammatory mediators (IL-8, TNF-α and IL-1ß) (P<0.05 - P<0.001); and 3) limit the depletion of cellular antioxidants (GSH and NADPH) (P<0.001). CONCLUSIONS: S-Mal and W-Mal have shown a potential cytoprotective activity when used together, and good anti-inflammatory and antioxidant effects when used either singularly or in combination. In light of our results, S-Mal and W-Mal could represent effective and safe options in the management of bacterial-induced or aggravated skin conditions.


Assuntos
Glicóis/farmacologia , Queratinócitos/efeitos dos fármacos , Extratos Vegetais/farmacologia , Salix/química , Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Citocinas/metabolismo , Humanos , Mediadores da Inflamação/metabolismo , Queratinócitos/patologia , Lipopolissacarídeos , Casca de Planta , Fatores de Tempo
10.
Pigment Cell Melanoma Res ; 31(4): 475-483, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29350885

RESUMO

To inquire into the role of the carboxyl group as determinant of the properties of 5,6-dihydroxyindole melanins, melanins from aerial oxidation of 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and its DHICA methyl ester (MeDHICA) were comparatively tested for their antioxidant activity. MALDI MS spectrometry analysis of MeDHICA melanin provided evidence for a collection of intact oligomers. EPR analysis showed g-values almost identical and signal amplitudes (ΔB) comparable to those of DHICA melanin, but spin density was one order of magnitude higher, with a different response to pH changes. Antioxidant assays were performed, and a model of lipid peroxidation was used to compare the protective effects of the melanins. In all cases, MeDHICA melanin performed better than DHICA melanin. This capacity was substantially maintained following exposure to air in aqueous buffer over 1 week or to solar simulator over 3 hr. Different from DHICA melanin, MeDHICA melanin was proved to be fairly soluble in different water-miscible organic solvents, suggesting its use in dermocosmetic applications.


Assuntos
Antioxidantes/química , Indóis/química , Melaninas/química , Esterificação , Concentração de Íons de Hidrogênio
11.
ACS Appl Mater Interfaces ; 10(9): 7670-7680, 2018 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-28937213

RESUMO

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 from DHI melanin and does not contain species compatible with DHI-based oligomers as primary building blocks; (b) PDA films and precipitate display a single main peak at m/ z 402 in common; (c) no species matching the range of m/ z values expected for cyclic porphyrin-type tetramers was detected in DHI melanin produced in the presence or in the absence of folic acid (FA) as templating agent, nor by oxidation of the 2,7'-dimer of DHI as putative precursor. 15N NMR resonances and Raman spectra predicted by extensive DFT calculations on porphyrin-type structures at various oxidation levels did not match spectral data for PDA or DHI melanin. Notably, unlike PDA, which gave structurally homogeneous films on quartz on atomic force microscopy (AFM) and micro-Raman spectroscopy, DHI melanin did not form any adhesive deposit after as long as 24 h. It is concluded that PDA film deposition involves structural components unrelated to DHI-based oligomers or porphyrin-type tetramers, which, on mechanism-based analysis, may arise by quinone-amine conjugation leading to polycyclic systems with extensive chain breakdown.

12.
Biomimetics (Basel) ; 2(3)2017 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-31105178

RESUMO

Conjugation of naturally occurring catecholic compounds with thiols is a versatile and facile entry to a broad range of bioinspired multifunctional compounds for diverse applications in biomedicine and materials science. We report herein the inhibition properties of the caffeic acid- dihydrolipoic acid S-conjugate, 2-S-lipoylcaffeic acid (LC), on mushroom tyrosinase. Half maximum inhibitory concentration (IC50) values of 3.22 ± 0.02 and 2.0 ± 0.1 µM were determined for the catecholase and cresolase activity of the enzyme, respectively, indicating a greater efficiency of LC compared to the parent caffeic acid and the standard inhibitor kojic acid. Analysis of the Lineweaver⁻Burk plot suggested a mixed-type inhibition mechanism. LC proved to be non-toxic on human keratinocytes (HaCaT) at concentrations up to 30 µM. These results would point to LC as a novel prototype of melanogenesis regulators for the treatment of pigmentary disorders.

13.
Sci Rep ; 7: 41532, 2017 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-28150707

RESUMO

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 the interplay of geometric order and disorder in 5,6-dihydroxyindole (DHI)-based oligomeric/polymeric structures play a central role, however the contributions of structural (scaffold-controlled) and redox (π-electron-controlled) disorder have remained uncharted. Herein, we report an integrated experimental-theoretical entry to eumelanin chromophore dynamics based on poly(vinyl alcohol)-controlled polymerization of a large set of 5,6-dihydroxyindoles and related dimers. The results a) uncover the impact of the structural scaffold on eumelanin optical properties, disproving the widespread assumption of a universal monotonic chromophore; b) delineate eumelanin chromophore buildup as a three-step dynamic process involving the rapid generation of oxidized oligomers, termed melanochromes (phase I), followed by a slow oxidant-independent band broadening (phase II) leading eventually to scattering (phase III); c) point to a slow reorganization-stabilization of melanochromes via intermolecular redox interactions as the main determinant of visible broadband absorption.


Assuntos
Absorção de Radiação , Luz , Melaninas/química , Evolução Biológica , Dimerização , Modelos Moleculares , Oxirredução , Álcool de Polivinil/química , Espectrofotometria Ultravioleta , Termodinâmica , Fatores de Tempo
14.
Sci Rep ; 5: 18447, 2015 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-26669666

RESUMO

Pheomelanin has been implicated in the increased susceptibility to UV-induced melanoma for people with light skin and red hair. Recent studies identified a UV-independent pathway to melanoma carcinogenesis and implicated pheomelanin's pro-oxidant properties that act through the generation of reactive oxygen species and/or the depletion of cellular antioxidants. Here, we applied an electrochemically-based reverse engineering methodology to compare the redox properties of human hair pheomelanin with model synthetic pigments and natural eumelanin. This methodology exposes the insoluble melanin samples to complex potential (voltage) inputs and measures output response characteristics to assess redox activities. The results demonstrate that both eumelanin and pheomelanin are redox-active, they can rapidly (sec-min) and repeatedly redox-cycle between oxidized and reduced states, and pheomelanin possesses a more oxidative redox potential. This study suggests that pheomelanin's redox-based pro-oxidant activity may contribute to sustaining a chronic oxidative stress condition through a redox-buffering mechanism.


Assuntos
Cabelo/química , Melaninas/química , Modelos Químicos , Pigmentação , Raios Ultravioleta , Cabelo/metabolismo , Humanos , Melaninas/metabolismo , Oxirredução/efeitos da radiação
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