RESUMO
Bacterial tyrosinase is a copper-containing metalloenzyme with diverse physio-chemical properties, that have been identified in various bacterial strains, including actinobacteria and proteobacteria. Tyrosinases are responsible for the rate-limiting catalytic steps in melanin biosynthesis and enzymatic browning. The physiological role of bacterial tyrosinases in melanin biosynthesis has been harnessed for the production of coloring and dyeing agents. Additionally, bacterial tyrosinases have the capability of cross-linking activity, demonstrated material functionalization applications, and applications in food processing with varying substrate specificities and stability features. These characteristics make bacterial tyrosinases a valuable alternative to well-studied mushroom tyrosinases. The key feature of substrate specificity of bacterial tyrosinase has been exploited to engineer biosensors that have the ability to detect the minimal amount of different phenolic compounds. Today, the world is facing the challenge of multi-drugs resistance in various diseases, especially antibiotic resistance, skin cancer, enzymatic browning of fruits and vegetables, and melanogenesis. To address these challenges, medicinal scientists are developing novel chemotherapeutic agents by inhibiting bacterial tyrosinases. To serve this purpose, heterocyclic compounds are of particular interest due to their vast spectrum of biological activities and their potential as effective tyrosinase inhibitors. In this chapter, a plethora of research explores applications of bacterial tyrosinases in different fields, such as the production of dyes and pigments, catalytic applications in organic synthesis, bioremediation, food and feed applications, biosensors, wool fiber coating and the rationalized synthesis, and structure-activity relationship of bacterial tyrosinase inhibitors.
Assuntos
Bactérias , Inibidores Enzimáticos , Monofenol Mono-Oxigenase , Monofenol Mono-Oxigenase/antagonistas & inibidores , Monofenol Mono-Oxigenase/metabolismo , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Bactérias/efeitos dos fármacos , Bactérias/enzimologia , Especificidade por Substrato , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/metabolismo , Humanos , Melaninas/biossíntese , Melaninas/antagonistas & inibidores , Melaninas/metabolismoRESUMO
Tyrosinases (TYR) play a key role in melanin biosynthesis by catalyzing two reactions: monophenolase and diphenolase activities. Despite low amino acid sequence homology, TYRs from various organisms (from bacteria to humans) have similar active site architectures and catalytic mechanisms. The active site of the TYRs contains two copper ions coordinated by histidine (His) residues. The catalytic mechanism of TYRs involves electron transfer between copper sites, leading to the hydroxylation of monophenolic compounds to diphenols and the subsequent oxidation of these to corresponding dopaquinones. Although extensive studies have been conducted on the structure, catalytic mechanism, and enzymatic capabilities of TYRs, some mechanistic aspects are still debated. This chapter will delve into the structure of the active site, catalytic function, and inhibition mechanism of TYRs. The goal is to improve our understanding of the molecular mechanisms underlying TYR activity. This knowledge can help in developing new strategies to modulate TYR function and potentially treat diseases linked to melanin dysregulation.
Assuntos
Domínio Catalítico , Monofenol Mono-Oxigenase , Humanos , Monofenol Mono-Oxigenase/metabolismo , Monofenol Mono-Oxigenase/química , Melaninas/metabolismo , Melaninas/biossíntese , Animais , Catálise , Biocatálise , OxirreduçãoRESUMO
Non-thermal plasma (NTP) is an emerging technology with extensive applications in biomedicine, including treatment of abnormal pigmentation. However, very few studies have investigated how plasma induces anti-melanogenesis. Here, liquid plasma was prepared by treating an NTP jet with helium and oxygen (as carrier gases) for 15 min in serum-free culture media. In the zebrafish model, pigmentation ratio was observed with or without liquid plasma. The anti-melanogenic effect of liquid plasma was evaluated in human melanocytes by assessing the expression of melanogenesis-related genes using western blotting, RT-PCR, and immunohistochemistry. Liquid plasma reduced pigmentation in the zebrafish model and inhibited melanin synthesis in primary human melanocytes. Intracellular reactive oxygen species levels decreased and Nrf2 expression increased in liquid plasma-treated melanocytes. Liquid plasma affected microphthalmia-associated transcription factor (MITF) and tyrosinase mRNA and protein levels, tyrosinase activity, and melanin content. Considering the role of Wnt/ß-catenin and PI3K/Akt pathways in melanogenesis, the effect of liquid plasma on this pathway was determined; liquid plasma decreased active ß-catenin, LEF1/TCF4, MITF, and tyrosinase levels in a time-dependent manner and inhibited the nuclear translocation of ß-catenin. This inhibition subsequently suppressed melanogenesis by downregulating MITF and tyrosinase. These results suggest that liquid plasma may be used for treating pigmentary disorders.
Assuntos
Melaninas , Melanócitos , Fator 2 Relacionado a NF-E2 , Peixe-Zebra , Animais , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/genética , Melanócitos/metabolismo , Melanócitos/efeitos dos fármacos , Melaninas/biossíntese , Melaninas/metabolismo , Humanos , Gases em Plasma/farmacologia , Fator de Transcrição Associado à Microftalmia/metabolismo , Fator de Transcrição Associado à Microftalmia/genética , Monofenol Mono-Oxigenase/metabolismo , Monofenol Mono-Oxigenase/genética , Regulação para Cima/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Via de Sinalização Wnt/efeitos dos fármacos , beta Catenina/metabolismo , MelanogêneseRESUMO
Inspired by the potent tyrosinase inhibitory activity of phenolic compounds with a 2-phenylbenzo[d]thiazole scaffold, we explored phenolic compounds 1-15 with 2-phenylbenzo[d]oxazole, which is isosterically related to 2-phenylbenzo[d]thiazole, as novel tyrosinase inhibitors. Among these, compounds 3, 8, and 13, featuring a resorcinol structure, exhibited significantly stronger mushroom tyrosinase inhibition than kojic acid, with compound 3 showing a nanomolar IC50 value of 0.51 µM. These results suggest that resorcinol plays an important role in tyrosinase inhibition. Kinetic studies using Lineweaver-Burk plots demonstrated the inhibition mechanisms of compounds 3, 8, and 13, while docking simulation results indicated that the resorcinol structure contributed to tyrosinase binding through hydrophobic and hydrogen bonding interactions. Additionally, these compounds effectively inhibited tyrosinase activity and melanin production in B16F10 cells and inhibited B16F10 tyrosinase activity in situ in a concentration-dependent manner. As these compounds showed no cytotoxicity to epidermal cells, melanocytes, or keratinocytes, they are appropriate for skin applications. Compounds 8 and 13 demonstrated substantially higher depigmentation effects on zebrafish larvae than kojic acid, even at 800- and 400-times lower concentrations than kojic acid, respectively. These findings suggest that 2-phenylbenzo[d]oxazole is a promising candidate for tyrosinase inhibition.
Assuntos
Melaninas , Simulação de Acoplamento Molecular , Monofenol Mono-Oxigenase , Preparações Clareadoras de Pele , Animais , Humanos , Camundongos , Agaricales/enzimologia , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Melaninas/biossíntese , Melaninas/antagonistas & inibidores , Estrutura Molecular , Monofenol Mono-Oxigenase/antagonistas & inibidores , Monofenol Mono-Oxigenase/metabolismo , Oxazóis/química , Oxazóis/farmacologia , Pironas , Resorcinóis/química , Resorcinóis/farmacologia , Preparações Clareadoras de Pele/farmacologia , Preparações Clareadoras de Pele/química , Relação Estrutura-Atividade , Peixe-ZebraRESUMO
Fungal contamination poses a serious threat to public health and food safety because molds can grow under stressful conditions through melanin accumulation. Although ultraviolet (UV) irradiation is popular for inhibiting microorganisms, its effectiveness is limited by our insufficient knowledge about UV tolerance in melanin-accumulating molds. In this study, we first confirmed the protective effect of melanin by evaluating the UV sensitivity of young and mature spores. Additionally, we compared UV sensitivity between spores with accumulated melanin and spores prepared with melanin biosynthesis inhibitors. We found that mature spores were less UV-sensitive than young spores, and that reduced melanin accumulation by inhibitors led to reduced UV sensitivity. These results suggest that melanin protects cells against UV irradiation. To determine the most effective wavelength for inhibition, we evaluated the wavelength dependence of UV tolerance in a yeast (Rhodotorula mucilaginosa) and in molds (Aspergillus fumigatus, Cladosporium halotolerans, Cladosporium sphaerospermum, Aspergillus brasiliensis, Penicillium roqueforti, and Botrytis cinerea). We assessed UV tolerance using a UV-light emitting diode (LED) irradiation system with 13 wavelength-ranked LEDs between 250 and 365 nm, a krypton chlorine (KrCl) excimer lamp device, and a low pressure (LP) Hg lamp device. The inhibition of fungi peaked at around 270 nm, and most molds showed reduced UV sensitivity at shorter wavelengths as they accumulated pigment. Absorption spectra of the pigments showed greater absorption at shorter wavelengths, suggesting greater UV protection at these wavelengths. These results will assist in the development of fungal disinfection systems using UV, such as closed systems of air and water purification.
Assuntos
Melaninas , Raios Ultravioleta , Melaninas/metabolismo , Melaninas/química , Melaninas/biossíntese , Esporos Fúngicos/efeitos da radiação , Esporos Fúngicos/metabolismo , Esporos Fúngicos/efeitos dos fármacos , Fungos/metabolismo , Fungos/efeitos da radiação , Fungos/efeitos dos fármacos , Rhodotorula/metabolismo , Rhodotorula/efeitos da radiação , Cladosporium/metabolismo , Cladosporium/químicaRESUMO
The important role of dihydroxynaphthalene-(DHN) melanin in enhancing fungal stress resistance and its importance in fungal development and pathogenicity are well-established. This melanin also aids biocontrol fungi in surviving in the environment and effectively infecting insects. However, the biosynthetic origin of melanin in the biocontrol agents, Metarhizium spp., has remained elusive due to the complexity resulting from the divergence of two DHN-like biosynthetic pathways. Through the heterologous expression of biosynthetic enzymes from these two pathways in baker's yeast Saccharomyces cerevisiae, we have confirmed the presence of DHN biosynthesis in M. roberstii, and discovered a novel naphthopyrone intermediate, 8, that can produce a different type of pigment. These two pigment biosynthetic pathways differ in terms of polyketide intermediate structures and subsequent modification steps. Stress resistance studies using recombinant yeast cells have demonstrated that both DHN and its intermediates confer resistance against UV light prior to polymerization; a similar result was observed for its naphthopyrone counterpart. This study contributes to the understanding of the intricate and diverse biosynthetic mechanisms of fungal melanin and has the potential to enhance the application efficiency of biocontrol fungi such as Metarhizium spp. in agriculture.
Assuntos
Vias Biossintéticas , Melaninas , Metarhizium , Saccharomyces cerevisiae , Metarhizium/metabolismo , Metarhizium/genética , Melaninas/metabolismo , Melaninas/biossíntese , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Naftóis/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Raios UltravioletaRESUMO
Significance: Near-infrared spectroscopy (NIRS) is a non-invasive optical method that measures changes in hemoglobin concentration and oxygenation. The measured light intensity is susceptible to reduced signal quality due to the presence of melanin. Aim: We quantify the influence of melanin concentration on NIRS measurements taken with a frequency-domain near-infrared spectroscopy system using 690 and 830 nm. Approach: Using a forehead NIRS probe, we measured 35 healthy participants and investigated the correlation between melanin concentration indices, which were determined using a colorimeter, and several key metrics from the NIRS signal. These metrics include signal-to-noise ratio (SNR), two measurements of oxygen saturation (arterial oxygen saturation, SpO 2 , and tissue oxygen saturation, StO 2 ), and optical properties represented by the absorption coefficient ( µ a ) and the reduced scattering coefficient ( µ s ' ). Results: We found a significant negative correlation between the melanin index and the SNR estimated in oxy-hemoglobin signals ( r s = - 0.489 , p = 0.006 ) and SpO 2 levels ( r s = - 0.413 , p = 0.023 ). However, no significant changes were observed in the optical properties and StO 2 ( r s = - 0.146 , p = 0.44 ). Conclusions: We found that estimated SNR and SpO 2 values show a significant decline and dependence on the melanin index, whereas StO 2 and optical properties do not show any correlation with the melanin index.
Assuntos
Melaninas , Razão Sinal-Ruído , Espectroscopia de Luz Próxima ao Infravermelho , Humanos , Melaninas/análise , Melaninas/metabolismo , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Masculino , Feminino , Adulto , Adulto Jovem , Saturação de Oxigênio/fisiologia , Oxigênio/metabolismo , Oxiemoglobinas/análise , Oximetria/métodos , Hemoglobinas/análiseRESUMO
For thousands of years, pearl and nacre powders have been important traditional Chinese medicines known for their skin whitening effects. To prepare the enzymatic hydrolysates of Hyriopsis cumingii nacre powder (NP-HCH), complex enzymatic hydrolysis by pineapple protease and of neutral protease was carried out after the powder was pre-treated with a high-temperature and high-pressure method. The peptides were identified using LC-MS/MS and picked out through molecular docking and molecular dynamics simulations. Subsequently, the tyrosinase inhibitory and antioxidant properties of novel tyrosinase inhibitory peptides were investigated in vitro. In addition, the enzymatic activity of tyrosinase in B16F10 cells as well as melanin content and antioxidant enzyme levels were also examined. The results showed that a tyosinase inhibitory peptide (Tyr-Pro-Asn-Pro-Tyr, YPNPY) with an efficient IC50 value of 0.545 ± 0.028 mM was identified. The in vitro interaction results showed that YPNPY is a reversible competitive inhibitor of tyrosinase, suggesting that it binds to the free enzyme. The B16F10 cell whitening test revealed that YPNPY can reduce the melanin content of B16F10 cells by directly inhibiting the activity of intracellular tyrosinase. Additionally, it indirectly affects melanin production by acting as an antioxidant. These results suggest that YPNPY could be widely used as a tyrosinase inhibitor in whitening foods and drugs.
Assuntos
Antioxidantes , Melaninas , Simulação de Acoplamento Molecular , Monofenol Mono-Oxigenase , Peptídeos , Monofenol Mono-Oxigenase/antagonistas & inibidores , Animais , Peptídeos/farmacologia , Peptídeos/química , Peptídeos/isolamento & purificação , Camundongos , Antioxidantes/farmacologia , Antioxidantes/química , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Linhagem Celular Tumoral , Melanoma Experimental/tratamento farmacológico , Simulação por Computador , Espectrometria de Massas em Tandem , Preparações Clareadoras de Pele/farmacologia , Preparações Clareadoras de Pele/química , Preparações Clareadoras de Pele/isolamento & purificação , Simulação de Dinâmica MolecularRESUMO
Excessive melanogenesis leads to hyperpigmentation-related cosmetic problems. UV exposure increases oxidative stress, which promotes melanogenesis-related signal pathways such as the PKA, microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), tyrosinase-related protein-1 (TRP1), and tyrosinase-related protein-2 (TRP2) pathways. Glycine is a source of endogenous antioxidants, including glutathione. Fermented fish collagen (FC) contains glycine; thus, we evaluated the effect of FC on decreasing melanogenesis via decreasing oxidative stress. The glycine receptor (GlyR) and glycine transporter-1 (GlyT1) levels were decreased in UV-irradiated keratinocytes; however, the expression levels of these proteins increased upon treatment with FC. The FC decreased oxidative stress, as indicated by the decreasing expression of NOX1/2/4, increased expression of GSH/GSSG, increased SOD activity, and decreased 8-OHdG expression in UV-irradiated keratinocytes. Administration of conditioned media from FC-treated keratinocytes to melanocytes led to decreased p38, PKC, MITF, TRP1, and TRP2 expression. These changes induced by the FC were also observed in UV-irradiated animal skin. FC treatment increased the expression of GlyR and GlyT, which was accompanied by decreased oxidative stress in the UV-irradiated skin. Moreover, the FC negatively regulated the melanogenesis signaling pathways, leading to decreased melanin content in the UV-irradiated skin. In conclusion, FC decreased UV-induced oxidative stress and melanogenesis in melanocytes and animal skin. FC could be used in the treatment of UV-induced hyperpigmentation problems.
Assuntos
Colágeno , Queratinócitos , Melaninas , Estresse Oxidativo , Raios Ultravioleta , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/efeitos da radiação , Raios Ultravioleta/efeitos adversos , Animais , Melaninas/biossíntese , Colágeno/metabolismo , Humanos , Queratinócitos/efeitos dos fármacos , Queratinócitos/efeitos da radiação , Queratinócitos/metabolismo , Peixes , Fermentação , Melanócitos/efeitos dos fármacos , Melanócitos/metabolismo , Melanócitos/efeitos da radiação , Antioxidantes/farmacologia , Transdução de Sinais/efeitos dos fármacos , Pele/efeitos dos fármacos , Pele/metabolismo , Pele/efeitos da radiação , MelanogêneseRESUMO
Tyrosinase is a crucial copper-containing enzyme involved in the production of melanin. Melasma, age spots, and freckles are examples of hyperpigmentation diseases caused by excess production of melanin. Inhibiting tyrosinase activity is a crucial method for treating these disorders along with various applications such as cosmetics, food technology, and medicine. Natural products have proven a rich source of tyrosinase inhibitors, with several molecules from plant, marine, and microbial sources showing potential inhibitory action. This chapter provides a complete overview of natural compounds that have been found as tyrosinase inhibitors, with emphasis on their structures, modes of action, and prospective applications.
Assuntos
Produtos Biológicos , Inibidores Enzimáticos , Monofenol Mono-Oxigenase , Monofenol Mono-Oxigenase/antagonistas & inibidores , Produtos Biológicos/farmacologia , Produtos Biológicos/química , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Humanos , Animais , Melaninas/antagonistas & inibidores , Melaninas/metabolismoRESUMO
Several dozen Mendelian mutants have been discovered in axolotl (Ambystoma mexicanum) populations, including several that affect pigmentation. Four recessive mutants have been described in the scientific literature and genes for three of these have been identified. Here we describe and genetically dissect copper, a mutant with an albino-like phenotype known only from the pet trade. We performed a cross segregating copper and wildtype color phenotypes and used bulked segregant RNA-Seq to identify a region on chromosome 6 that was enriched for single-nucleotide polymorphisms (SNPs) between the color phenotypes. This region included Tyrosinase-like Protein 1 (Tyrp1), a melanin synthesis protein that when mutated, is associated with lighter than black melanin coloration in animal models and oculocutaneous albinism in humans. Inspection of RNA-Seq reads identified a single nucleotide deletion that is predicted to change the coding frame, introduce a premature stop codon in exon 6 and yield a truncated Tyrp1 protein in copper individuals. Using CRISPR-Cas9 editing, we show that wildtype Tyrp1 crispants exhibit copper pigmentation, thus confirming Tyrp1 as the copper locus. Our results suggest that commercial and hobbyist axolotl populations may harbor useful mutants for biological research.
Assuntos
Ambystoma mexicanum , Cobre , Mutação , Pigmentação , Polimorfismo de Nucleotídeo Único , Animais , Ambystoma mexicanum/genética , Cobre/metabolismo , Pigmentação/genética , Fenótipo , Oxirredutases/genética , Oxirredutases/metabolismo , Melaninas/metabolismo , Melaninas/genéticaRESUMO
Pterostilbene (PTS), which is abundant in blueberries, is a dimethyl derivative of the natural polyphenol resveratrol (RES). Several plant species, including peanuts and grapes, also produce PTS. Although RES has a wide range of health benefits, including anti-cancer properties, PTS has a robust pharmacological profile that includes a better intestinal absorption and an increased hepatic stability compared to RES. Indeed, PTS has a higher bioavailability and a lower toxicity compared to other stilbenes, making it an attractive drug candidate for the treatment of various diseases, including diabetes, cancer, cardiovascular disease, neurodegenerative disorders, and aging. We previously reported that RES serves as a substrate for tyrosinase, producing an o-quinone metabolite that is highly cytotoxic to melanocytes. The present study investigated whether PTS may also be metabolized by tyrosinase, similarly to RES. PTS was oxidized as a substrate by tyrosinase to form an o-quinone, which reacted with thiols, such as N-acetyl-L-cysteine, to form di- and tri-adducts. We also confirmed that PTS was taken up and metabolized by human tyrosinase-expressing 293T cells in amounts several times greater than RES. In addition, PTS showed a tyrosinase-dependent cytotoxicity against B16BL6 melanoma cells that was stronger than RES and also inhibited the formation of melanin in B16BL6 melanoma cells and in the culture medium. These results suggest that the two methyl groups of PTS, which are lipophilic, increase its membrane permeability, making it easier to bind to intracellular proteins, and may therefore be more cytotoxic to melanin-producing cells.
Assuntos
Melaninas , Monofenol Mono-Oxigenase , Estilbenos , Monofenol Mono-Oxigenase/metabolismo , Humanos , Estilbenos/farmacologia , Estilbenos/metabolismo , Estilbenos/química , Animais , Melaninas/metabolismo , Melaninas/biossíntese , Camundongos , Resveratrol/farmacologia , Resveratrol/análogos & derivados , Ativação Metabólica , Linhagem Celular Tumoral , Células HEK293 , Melanócitos/efeitos dos fármacos , Melanócitos/metabolismo , Sobrevivência Celular/efeitos dos fármacosRESUMO
Tyrosinase, a pivotal enzyme in melanin biosynthesis, orchestrates the pigmentation process in humans, affecting skin, hair, and eye color. This chapter examines the three-dimensional structure and functional aspects of tyrosinases from various sources, highlighting their di-metal ion coordination crucial for catalytic activity. I explore the biochemical pathwayscheme catalyzed by tyrosinase, specifically the oxidation of L-tyrosine to L-dopaquinone, a precursor in melanin synthesis. Detailed structural analyses, including 3D structures obtained from X-ray crystallography and computational modeling, reveal key insights into the enzyme's active site, variations among tyrosinases, and substrate binding mechanisms. Furthermore, the chapter investigates the role of human tyrosinase variants, their inhibitors, essential for developing therapeutic and cosmetic applications targeting hyperpigmentation disorders. Structural characterizations of tyrosinase-inhibitor complexes provide a foundation for designing effective inhibitors, with compounds like kojic acid, L-mimosine, and (S)-3-amino-tyrosine demonstrating significant inhibitory potential. This comprehensive examination of the structure, function, and inhibition mechanisms of tyrosinase offers avenues for innovative treatments in biotechnology, health, and beyond.
Assuntos
Monofenol Mono-Oxigenase , Humanos , Domínio Catalítico , Cristalografia por Raios X , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Melaninas/metabolismo , Melaninas/biossíntese , Melaninas/química , Modelos Moleculares , Monofenol Mono-Oxigenase/antagonistas & inibidores , Monofenol Mono-Oxigenase/metabolismo , Monofenol Mono-Oxigenase/química , Conformação Proteica , Tirosina/química , Tirosina/metabolismoRESUMO
Melanin, which is produced by melanocytes and spread over keratinocytes, is responsible for human skin browning. There are several processes involved in melanogenesis, mostly prompted by enzymatic activities. Tyrosinase (TYR), a copper containing metalloenzyme, is considered the main actor in melanin production, as it catalyzes two crucial steps that modify tyrosine residues in dopaquinone. For this reason, TYR inhibition has been exploited as a possible mechanism of modulation of hyper melanogenesis. There are various types of molecules used to block TYR activity, principally used as skin whitening agents in cosmetic products, e.g., tretinoin, hydroquinone, azelaic acid, kojic acid, arbutin and peptides. Peptides are highly valued for their versatile nature, making them promising candidates for various functions. Their specificity often leads to excellent safety, tolerability, and efficacy in humans, which can be considered their primary advantage over traditional small molecules. There are several examples of tyrosinase inhibitor peptides (TIPs) operating as possible hypo-pigmenting agents, which can be classified according to their origin: natural, hybrid or synthetically produced. Moreover, the possibility of variating their backbones, introducing non-canonical amino acids or modifying one or more peptide bond(s), to obtain peptidomimetic molecules, is an added value to avoid or delay proteolytic activity, while the possibility of conjugation with other bioactive peptides or organic moieties can bring other specific activity leading to dual-functional peptides.
Assuntos
Inibidores Enzimáticos , Monofenol Mono-Oxigenase , Peptídeos , Peptidomiméticos , Monofenol Mono-Oxigenase/antagonistas & inibidores , Monofenol Mono-Oxigenase/metabolismo , Humanos , Peptidomiméticos/farmacologia , Peptidomiméticos/química , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Peptídeos/química , Peptídeos/farmacologia , Animais , Melaninas/metabolismo , Melaninas/antagonistas & inibidoresRESUMO
Collagen is considered to be an intercellular adhesive that prevents tissue stretching or damage. It is widely utilized in cosmetic skin solutions, drug delivery, vitreous substitutions, 3D cell cultures, and surgery. In this study, we report the development of a green technology for manufacturing collagen peptides from flatfish skin using ultrasound and enzymatic treatment and a subsequent assessment on skin functionality. First, flatfish skin was extracted using ultrasound in distilled water (DW) for 6 h at 80 °C. Molecular weight analysis via high-performance liquid chromatography (HPLC) after treatment with industrial enzymes (alcalase, papain, protamex, and flavourzyme) showed that the smallest molecular weight (3.56 kDa) was achieved by adding papain (0.5% for 2 h). To determine functionality based on peptide molecular weight, two fractions of 1100 Da and 468 Da were obtained through separation using Sephadex™ G-10. We evaluated the effects of these peptides on protection against oxidative stress in human keratinocytes (HaCaT) cells, inhibition of MMP-1 expression in human dermal fibroblast (HDF) cells, reduction in melanin content, and the inhibition of tyrosinase enzyme activity in murine melanoma (B16F10) cells. These results demonstrate that the isolated low-molecular-weight peptides exhibit superior skin anti-oxidant, anti-wrinkle, and whitening properties.
Assuntos
Colágeno , Peptídeos , Pele , Animais , Humanos , Pele/efeitos dos fármacos , Pele/metabolismo , Colágeno/metabolismo , Peptídeos/química , Peptídeos/farmacologia , Camundongos , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismo , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Ondas Ultrassônicas , Estresse Oxidativo/efeitos dos fármacos , Antioxidantes/farmacologia , Antioxidantes/química , Células HaCaT , Peso Molecular , Melaninas , Monofenol Mono-Oxigenase/metabolismoRESUMO
Cladosporium cladosporioides are the pigmented soil fungi containing melanin. The aim of this work was to determine the influence of amphotericin B on free radicals in the natural melanin isolated from pigmented fungi Cladosporium cladosporioides and to compare it with the effect in synthetic DOPA-melanin. Electron paramagnetic resonance (EPR) spectra were measured at X-band (9.3 GHz) with microwave power in the range of 2.2-70 mW. Amplitudes, integral intensities, linewidths of the EPR spectra, and g factors, were analyzed. The concentrations of free radicals in the tested melanin samples were determined. Microwave saturation of EPR lines indicates the presence of pheomelanin in addition to eumelanin in Cladosporium cladosporioides. o-Semiquinone free radicals in concentrations ~1020 [spin/g] exist in the tested melanin samples and in their complexes with amphotericin B. Changes in concentrations of free radicals in the examined synthetic and natural melanin point out their participation in the formation of amphotericin B binding to melanin. A different influence of amphotericin B on free radical concentration in Cladosporium cladosporioides melanin and in DOPA-melanin may be caused by the occurrence of pheomelanin in addition to eumelanin in Cladosporium cladosporioides. The advanced spectral analysis in the wide range of microwave powers made it possible to compare changes in the free radical systems of different melanin polymers. This study is important for knowledge about the role of free radicals in the interactions of melanin with drugs.
Assuntos
Anfotericina B , Cladosporium , Melaninas , Melaninas/metabolismo , Cladosporium/efeitos dos fármacos , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Anfotericina B/farmacologia , Radicais Livres/metabolismo , Di-Hidroxifenilalanina/química , Di-Hidroxifenilalanina/metabolismo , Di-Hidroxifenilalanina/análogos & derivadosRESUMO
Coreopsis tinctoria Nutt. is an important medicinal plant in traditional Uyghur medicine. The skin-lightening potential of the flower has been recognized recently; however, the active compounds responsible for that are not clear. In this work, tyrosinase, a target protein for regulating melanin synthesis, was immobilized on the Whatman paper for the first time to screen skin-lightening compounds present in the flower. Quercetagetin-7-O-glucoside (1), marein (2), and okanin (3) were found to be the enzyme inhibitors. The IC50 values of quercetagetin-7-O-glucoside (1) and okanin (3) were 79.06 ± 1.08 µM and 30.25 ± 1.11 µM, respectively, which is smaller than 100.21 ± 0.11 µM of the positive control kojic acid. Enzyme kinetic analysis and molecular docking were carried out to investigate their inhibition mechanism. Although marein (2) showed a weak inhibition effect in vitro, it inhibited the intracellular tyrosinase activity and diminished melanin production in melanoma B16 cells as did the other two inhibitors. The paper-based ligand fishing method developed in this work makes it effective to quickly screen tyrosinase inhibitors from natural products. This is the first report on the tyrosinase inhibitory effect of those three compounds, showing the promising potential of Coreopsis tinctoria for the development of herbal skin-lightening products.
Assuntos
Coreopsis , Inibidores Enzimáticos , Simulação de Acoplamento Molecular , Monofenol Mono-Oxigenase , Monofenol Mono-Oxigenase/antagonistas & inibidores , Monofenol Mono-Oxigenase/metabolismo , Coreopsis/química , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Animais , Melaninas/antagonistas & inibidores , Melaninas/biossíntese , Ligantes , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Camundongos , Enzimas Imobilizadas/química , Enzimas Imobilizadas/antagonistas & inibidores , CinéticaRESUMO
Based on the hypothesis that the 2-mercaptoacetamide moiety chelates the copper ions of tyrosinase, 2-mercapto-N-arylacetamide (2-MAA) analogs were designed and synthesized as potential tyrosinase inhibitors. Four 2-MAA analogs showed low IC50 values ranging from 0.95 to 2.0 µM against mushroom tyrosinase, which was 12-26 times lower than that of kojic acid (IC50 value = 24.3 µM). However, according to a copper ion chelation experiment performed, the 2-MAA analogs did not participate in chelation with copper ions. To identify the mode of inhibition of the 2-MAA analogs, kinetic studies were performed, and the results were supported by docking results. In addition, docking simulation results suggested that the 2-MAA analogs strongly inhibited tyrosinase activity because of the hydrogen bonding of the amide NH group and the hydrophobic interaction of the aryl ring instead of chelation with copper ions. In experiments using B16F10 cells, 2-MAA analogs were shown to inhibit melanin production by inhibiting cellular tyrosinase activity. Western blotting showed that in addition to directly inhibiting tyrosinase activity, analog 7 also has an anti-melanogenic effect by inhibiting the expression of microphthalmia-associated transcription factor (MITF) and tyrosinase. The 2-MAA analogs showed no appreciable cytotoxicity against HaCaT and B16F10 cells, making them suitable for dermal applications. In a depigmentation experiment using zebrafish embryos, analogs 1 and 2 showed more potent depigmentation effects than kojic acid even at 1000 times lower concentration than that of kojic acid. These results suggest that the 2-MAA analogs are promising anti-melanogenic agents that can inhibit most tyrosinases in various species.
Assuntos
Acetamidas , Inibidores Enzimáticos , Melaninas , Monofenol Mono-Oxigenase , Peixe-Zebra , Animais , Monofenol Mono-Oxigenase/antagonistas & inibidores , Monofenol Mono-Oxigenase/metabolismo , Camundongos , Acetamidas/farmacologia , Acetamidas/química , Acetamidas/síntese química , Melaninas/antagonistas & inibidores , Melaninas/metabolismo , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Agaricales/enzimologia , Simulação de Acoplamento Molecular , Relação Estrutura-Atividade , Linhagem Celular Tumoral , Estrutura Molecular , Relação Dose-Resposta a Droga , HumanosRESUMO
Cryptococcus neoformans has emerged as a frontrunner among deadly fungal pathogens and is particularly life-threatening for many HIV-infected individuals with compromised immunity. Multiple virulence factors contribute to the growth and survival of C. neoformans within the human host, the two most prominent of which are the polysaccharide capsule and melanin. As both of these features are associated with the cell wall, we were interested to explore possible cooperative or competitive interactions between these two virulence factors. Whereas capsule thickness had no effect on the rate at which cells became melanized, build-up of the melanin pigment layer resulted in a concomitant loss of polysaccharide material, leaving melanized cells with significantly thinner capsules than their nonmelanized counterparts. When melanin was provided exogenously to cells in a transwell culture system we observed a similar inhibition of capsule growth and maintenance. Our results show that melanin sequesters calcium thereby limiting its availability to form divalent bridges between polysaccharide subunits required for outer capsule assembly. The decreased ability of melanized cells to incorporate exported polysaccharide into the growing capsule correlated with the amount of shed polysaccharide, which could have profound negative impacts on the host immune response.
Assuntos
Cálcio , Parede Celular , Cryptococcus neoformans , Melaninas , Cryptococcus neoformans/metabolismo , Cryptococcus neoformans/crescimento & desenvolvimento , Melaninas/metabolismo , Cálcio/metabolismo , Parede Celular/metabolismo , Cápsulas Fúngicas/metabolismo , Humanos , Polissacarídeos/metabolismo , Polissacarídeos Fúngicos/metabolismoRESUMO
Long-term exposure to ultraviolet (UV) radiation induces skin photoaging, which manifests as oxidative stress, inflammation, and collagen degradation. Multiple approaches (topical or systemic retinoids, antioxidants, alpha-hydroxy acids, laser, surgery) are used in the treatment of photoaged skin, and the use of topical retinoids is currently a primary clinical treatment. Previous studies revealed that retinoic acid promotes keratinocyte proliferation and reduces melanin deposition and matrix metalloproteinase (MMP) secretion; it also causes potential allergic and inflammatory damage to the skin. This study aimed to investigate the therapeutic effects and mechanisms of trifarotene, a functional retinoic acid analog, on UV-irradiated photoaging ICR and BALB/c nude mice and UVB photodamaged human epidermal keratinocyte (HaCaT) cells by examining indicators such as collagen, oxidoreductase, and inflammatory factor presence through histochemical staining, Western blot, and ELISA. Results suggested that trifarotene significantly reduced UV-induced photoaging in mouse skin tissue, potentially by reducing oxidative stress damage and inflammatory factor release, and inhibiting melanin deposition and collagen degradation by downregulating MMP expression. Concentrations of malondialdehyde, tyrosinase, interleukin-6, interleukin- 12, and tumor necrosis factor-alpha in photoaged skin decreased, while SOD content in photodamaged HaCaT cells significantly increased. Trifarotene (3.3 µmol L-1) inhibited phosphorylated JNK and c-Jun expression both independently and collaboratively with the JNK activator anisomycin, demonstrating that trifarotene mitigates UV-induced collagen degradation and apoptosis through inhibition of the JNK/c-Jun/MMPs signaling pathway.