Melanin Formation Research Articles

Anti-Melanogenic Effect of Dendropanax morbiferus and Its Active Components via Protein Kinase A/Cyclic Adenosine Monophosphate-Responsive Binding Protein- and p38 Mitogen-Activated Protein Kinase-Mediated Microphthalmia-Associated Transcription Factor Downregulation.

Dendropanax morbiferus H. Lév has been reported to have some pharmacologic activities and also interested in functional cosmetics. We found that the water extract of D. morbiferus leaves significantly inhibited tyrosinase activity and melanin formation in α-melanocyte stimulating hormone (MSH)-induced B16-F10 cells. D. morbiferus reduced melanogenesis-related protein levels, such as microphthalmia−associated transcription factor (MITF), TRP-1, and TRP-2, without any cytotoxicity. Two active ingredients of D. morbiferus, (10E)-9,16-dihydroxyoctadeca-10,17-dien-12,14-diynoate (DMW-1) and (10E)-(–)-10,17-octadecadiene-12,14-diyne-1,9,16-triol (DMW-2) were identified by testing the anti-melanogenic effects and then by liquid chromatography-tandem mass spectrometry (LC/MS/MS) analysis. DMW-1 and DMW-2 significantly inhibited melanogenesis by the suppression of protein kinase A (PKA)/cyclic AMP (cAMP)-responsive binding protein (CREB) and p38 MAPK phosphorylation. DMW-1 showed a better inhibitory effect than DMW-2 in α-MSH-induced B16-F10 cells. D. morbiferus and its active component DMW-1 inhibited melanogenesis through the downregulation of cAMP, p-PKA/CREB, p-p38, MITF, TRP-1, TRP-2, and tyrosinase. These results indicate that D. morbiferus and DMW-1 may be useful ingredients for cosmetics and therapeutic agents for skin hyperpigmentation disorders.

The deubiquitinating enzyme MoUbp8 is required for infection-related development, pathogenicity, and carbon catabolite repression in Magnaporthe oryzae.

Deubiquitination is an essential regulatory step in the Ub-dependent pathway. Deubiquitinating enzymes (DUBs) mediate the removal of ubiquitin moieties from substrate proteins, which are involved in many regulatory mechanisms. As a component of the DUB module (Ubp8/Sgf11/Sus1/Sgf73) in the SAGA (Spt-Ada-Gcn5-acetyltransferase) complex, Ubp8 plays a crucial role in both Saccharomyces cerevisiae and humans. In S. cerevisiae, Ubp8-mediated deubiquitination regulates transcriptional activation processes. To investigate the contributions of Ubp8 to physiological and pathological development of filamentous fungi, we generated the deletion mutant of ortholog MoUBP8 (MGG-03527) in Magnaporthe oryzae (syn. Pyricularia oryzae). The ΔMoubp8 strain showed reduced sporulation, pathogenicity, and resistance to distinct stresses. Even though the conidia of the ΔMoubp8 mutant were delayed in appressorium formation, the normal and abnormal (none-septum or one-septum) conidia could finally form appressoria. Reduced melanin in the ΔMoubp8 mutant is highly responsible for the attenuated pathogenicity since the appressoria of the ΔMoubp8 mutant was much more fragile than those of the wild type, due to the defective turgidity. The weakened ability to detoxify or scavenge host-derived reactive oxygen species (ROS) further restricted the invasion of the pathogen. We also showed that carbon derepression, on the one hand, rendered the ΔMoubp8 strain highly sensitive to allyl alcohol, on the other hand, it enhances the resistance of the MoUBP8 defective strain to deoxyglucose. Overall, we suggest that MoUbp8 is not only required for sporulation, melanin formation, appressoria development, and pathogenicity but also involved in carbon catabolite repression of M. oryzae.

Anti-melanogenic Effects of Kojic Acid and Hydroxycinnamic Acid Derivatives

Melanin provides photoprotection against UV irradiation, but excessive melanin accumulation can cause several problems such as darkened skin, melasma, and freckles. Although many anti-melanogenic agents have been developed for skin-whitening cosmetics, safety issues have been raised regarding these products. As natural substances are often non-toxic and are considered by some to be safer than synthetic compounds, various attempts have been made to synthesize active derivatives from natural substances. In this study, we evaluated the anti-melanogenic effects of four synthesized derivatives (compound 2a, 2b, 2c, and 2d) of kojic and hydroxycinnamic acids which are natural anti-melanogenic substances. Three of these derivatives (2a, 2b, and 2c) inhibited tyrosinase, which catalyzes a rate-limiting step of melanogenesis. Additionally, cell viability and melanin formation were investigated using B16F10 melanoma cells. Compounds 2b and 2c exhibited cytotoxicity towards B16F10 melanoma cells, while compound 2a caused a significant decrease in melanin formation without cytotoxicity. Thus, compound 2a may be viable as a potent skin-whitening agent derived from natural compounds.

Effective Compounds From Caesalpinia sappan L. on the Tyrosinase In Vitro and In Vivo

Caesalpinia sappan L. has been used as an herbal medicine to treat skin damage as a facial cleanser. In this study, 8 known compounds (1-8), (3 R,4 S)-3-(3′,4′-hydroxybenzyl)-3,4-dihydro-2″,3″-dimethyl-3 H-[1,3]dioxolo [4,5-c]chromen-7-ol (1), brazilin (2), protosappanin A (3), protosappanin C (4), protosappanin B (5), caesalpin J (6), sappanone B (7), and sappanchalcone (8), were isolated from the 70% ethanol extract of C. sappan. The effects of 8 compounds and extracts of C. sappan on tyrosinase were assayed in vitro and in vivo. The results indicated that compounds 1, 2, 4, and 7 had activating effects on the tyrosinase. The experiments of enzyme kinetics showed that compounds 3 and 6 were competitive inhibitors on tyrosinase, while compound 6 was anticompetitive inhibitor. The 70% ethanol extract of C. sappan could reduce the contents of tyrosinase in rat serum, ie, the 70% ethanol extracts of C. sappan could inhibit the formation of melanin in vivo. Compounds 2, 3, 5, and 6 promoted the formation of tyrosinase in rat serum, while compound 7 inhibited the synthesis of tyrosinase in rat serum.

Melanogenesis and its associated signalings

Introduction: Melanogenesis is the mechanism of melanin formation in the skin or hair, which is produced by melanosomes in melanocytes. Melanin is the main coloring pigment of the skin, hair and eyes, and also functions as a photoprotection against ultra-violet (UV) exposure.Methods: A total 20 relevant literatures which focused on skin pigmentation and melanogenesis were used to construct this review. The articles were published from 1998-2018. Most of the literatures were basic research and the clinical information were extracted from their discussion.Result: The process of melanogenesis starts from the migrational process of melanoblasts which are precursors of melanocyte cells originating from the neural crest into the epidermal layer and hair follicles. Many factors play a role in melanogenis both intrinsically and extrinsically, the dominant intrinsic factor is Melanocyte Stimulating Hormone-α (α-MSH) while the extrinsic factor that plays a role is UV ray.Conclusion: Melanogenesis is a complex process which influenced by a wide array of internal and external factors with α-MSH and UV ray act as the main regulators. Due to delicate nature of this process, defect in a certain stage could result in significant medical condition.

Structural and Functional Tailoring of Melanin-Like Polydopamine Radical Scavengers

Melanin is a ubiquitous but poorly understood polymeric, dark brown to black pigment biomaterial found both in nature and by organic synthesis. Its structural heterogeneity and disordered covalent/...

Conventional detection and quantification real-time PCR of the pks-1 gene of Chaetomium globosum.

Chaetomium globosum is known as a potential biocontrol indicator against various soil and seedborne pathogens. Precise data are necessary for population monitoring of C. globosum for its effective use in agriculture. A sequence-characterized amplified region marker has been applied for the detection of this biocontrol agent, which will help to detect C. globosum at the site of its application. Out of 17 isolates of C. globosum, only 8 isolates of C. globosum amplified a monomorphic band of 1,900 bp. C. globosum is known for producing chaetoglobosin A. The pks-1 gene is unique in C. globosum in that it is involved in chaetoglobosin A production, melanin formation, and sporulation. Real-time PCR of pks-1 was used to compare the expressions of the pks-1 gene and chaetoglobosin A biosynthesis and sporulation. It was found that the sporulation of C. globosum was associated with the levels of pks-1 gene expression; Cg2 isolate showed high expression of the pks-1 gene, 41.21%, and also produced a great number of spores and perithecia. The association between the pks-1 gene expression and chaetoglobosin A production was estimated. The Pks-1 gene was expressed by all C. globosum isolates except one isolate, C1, which is another species of Chaetomium. In addition, all C. globosum isolates produced chaetoglobosin A with different concentrations and did not express the same levels of pks-1. This finding may be a result of the solvent type used in the extraction.

Nitrogen concentration affects amphotericin B and fluconazole tolerance of pathogenic cryptococci.

Environmental stress often causes phenotypic changes among pathogenic cryptococci, such as altered antifungal susceptibility, changes in capsule and melanin formation, as well as altered levels of the membrane sterol and antifungal target, ergosterol. We therefore hypothesised that nitrogen limitation, a prevalent environmental stress in the natural habitat of these yeasts, might affect virulence and antifungal susceptibility. We tested the effect of different nitrogen concentrations on capsule, melanin and ergosterol biosynthesis, as well as amphotericin B (AmB) and fluconazole (FLU) susceptibility. This was achieved by culturing cryptococcal strains representing Cryptococcus neoformans and Cryptococcus gattii in media with high (0.53g/l), control (0.42g/l) and low (0.21g/l) NH4Cl concentrations. India ink staining was used to determine capsule thickness microscopically, while melanin and ergosterol content were determined spectrophotometrically. We found that lower nitrogen concentrations enhanced both ergosterol and capsule biosynthesis, while a variable effect was observed on melanisation. Evaluation of drug tolerance using time-kill methodology, as well as tests for FLU heteroresistance, revealed that the low nitrogen cultures had the highest survival percentages in the presence of both AmB and FLU, and showed the highest frequency of FLU heteroresistance, suggesting that nitrogen concentration may indeed influence drug tolerance.

Fabrication of Carboxylmethyl Chitosan Nanocarrier via Self-Assembly for Efficient Delivery of Phenylethyl Resorcinol in B16 Cells.

Micro-molecular drugs have special advantages to cope with challenging diseases, however their structure, physical and chemical properties, stability, and pharmacodynamics have more requirements for the way they are delivered into the body. Carrier-based drug delivery systems can circumvent many limited factors of drug delivery and increase their bioavailability. In this context, stable drug nanocarriers of alkaline amino acids (arginine, Arg) modified conjugated linoleic acid-carboxymethyl chitosan (CLA-CMCS) conjugate were developed, which could generate supramolecular micelles to effectively encapsulate the tyrosinase inhibitor phenylethyl resorcinol (PR). The resulting CCA-NPs were spherical nanoparticles with a mean size around 175 nm. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and cellular uptake investigation demonstrated that the CCA-NPs were non-cytotoxic and had excellent cell transport ability. In addition, these CCA-NPs were able to effectively deliver PR and inhibited melanin formation to reduce pigmentation by enhancing cellular uptake. In conclusion, our research indicated that nanocarriers based on self-assembly amphiphilic polymers constituted a promising and effective drug delivery system in hyperpigmentation targeting.

Melanin formation in barley grain occurs within plastids of pericarp and husk cells

Melanins are a class of darkly pigmented biopolymers which are widely distributed among living organisms. The molecular and cellular mechanisms adopted by bacteria, fungi and animals to synthesize melanin, have been well described, but less is known regarding their production in plants. Here, a pair of barley near isogenic lines, bred to differ with respect to the pigmentation of the spike, was compared in order to understand the tissue and cellular location of melanin deposition. The melanic nature of the pigments purified from black spikes was confirmed by a series of solubility tests and Fourier transform infrared spectroscopy. An analysis of grains harvested at various stages of their development revealed that intracellular pigmented structures first appeared in the pericarp and the husk of black spike plants at early dough stage. The co-localization of these structures with red autofluorescence suggested that they form in chloroplast-derived plastids, here designated “melanoplasts”. Differences in dynamics of plastid internal structure during grain ripening were detected between the lines by transmission electron microscopy. Both lines accumulated plastoglobuli inside plastids, which persisted in black grain pericarp tissue up to the hard dough stage, while neither plastoglobuli nor any plastids were observed in grain of the control line at this stage. The role of plastoglobuli in melanin synthesis is discussed.

Melanin production as a visual indicator of conjugal transfer in Streptomyces.

To visualize transfer of plasmid in Streptomyces during conjugation, we constructed a conjugative plasmid that harbored melC operon encoding an extracellular tyrosinase and placed it in Streptomyces hosts which were defective in expressing the operon. Hyphae of these donors were mixed with hyphae of a plasmidless recipient, which could express melC, and plated on a solid medium supplemented with tyrosine. After 8 to 9h of incubation, melanin started to appear in the mating mixture, indicating that the plasmid had entered the recipient and started to synthesize tyrosinase, which in turn catalyzed the formation of melanin. This visual monitoring system allows quick demonstration of conjugal transfer without tedious genetic or biochemical procedure commonly used. It may be applied to most Streptomyces species and may also be used for monitoring chromosome transfer.

Copper and Zinc Status in Psoriasis: Correlation with Severity.

Psoriasis is a common and an inflammatory skin disease. Trace elements play an important role in the skin metabolism such as keratinisation and melanin formation as well as immunological and inflammatory reactions. Henceforth, the present study was aimed to evaluate the essential metals with special reference to Cu and Zn. In this study, 72 psoriatic patients and 50 controls were enrolled. On the basis of PASI score psoriatic group comprising of 48 mild and 24 severe psoriatic patients were grouped. The serum trace elements analysis in the subjects revealed that serum Cu levels and Cu/Zn ratio was significantly higher in the psoriatic patients as compared to controls. Interestingly, severity of the psoriasis was well correlated with the serum Cu levels. Taking together, all these findings suggest that Cu may be a major culprit in the pathogenesis as well as in the severity of the disease.

Arachnid Hemocyanins.

Hemocyanin (Hc), a copper-containing extracellular multimeric protein, is the major protein component of hemolymph in different arachnid groups. Hc possesses 7 or 8 very well-characterized types of monomers with molecular weights ranging from 70 to 85kDa, organized in hexamers or multiple of hexamers. The present chapter compiles the existing data with relation to the function of this protein in the arachnids. Hc has as main function the reversible transport of O2, but it shows many secondary though not less important functions. With reference to this, it has been described that Hc can transport hydrophobic molecules (lipid-derived hormones and lipids) to the different organs, having a key role in the lipid transport system. In arachnids, like in other arthropods and invertebrates, Hc has phenoloxidase function which is related to different metabolic processes such as melanin formation and defense against pathogens. In addition, Hc has additional defensive functions since it can serve as precursor for the production of antimicrobial peptides. In short, the evolution of this protein has led to the development of multiple functions essential for organisms possessing this protein.

Insect Hemolymph Immune Complexes.

Insects possess powerful immune systems that have evolved to defend against wounding and environmental pathogens such as bacteria, fungi, protozoans, and parasitoids. This surprising sophistication is accomplished through the activation of multiple immune pathways comprised of a large array of components, many of which have been identified and studied in detail using both genetic manipulations and traditional biochemical techniques. Recent advances indicate that certain pathways activate arrays of proteins that interact to form large functional complexes. Here we discuss three examples from multiple insects that exemplify such processes, including pathogen recognition, melanization, and coagulation. The functionality of each depends on integrating recognition with the recruitment of immune effectors capable of healing wounds and destroying pathogens. In both melanization and coagulation, protein interactions also appear to be essential for enzymatic activities tied to the formation of melanin and for the recruitment of hemocytes. The importance of these immune complexes is highlighted by the evolution of mechanisms in pathogens to disrupt their formation, an example of which is provided. While technically difficult to study, and not alwaysreadily amenable to dissection through genetics, modern mass spectrometry has become an indispensable tool in the study of these higher-order protein interactions. The formation of immune complexes should be viewed as an essential and emerging frontier in the study of insect immunity.

The activity of avocado (Persea americana Mill.) seed extract containing catechin as a skin lightening agent

Context: Indonesia is a tropical country with high UV rays. UV rays can increase melanin synthesis in the skin and cause the skin to become darker and hyperpigmented. One way to overcome this problem is the use of skin lightening agents through the mechanism of tyrosinase inhibition. Flavonoids have antioxidant activity and inhibit the process of melanogenesis. Also, avocado seeds contain secondary metabolites of flavonoids in the form of catechin. Aims: To determine the potential and activity of catechin as skin lightening agent against the target protein, tyrosinase, by in silico test using molecular docking method and in vitro test compared to kojic acid. Methods: In silico assay was carry out using a computational method with autodock 4.2 program to demonstrate the affinity of active compound (catechin) with tyrosinase as the target protein by evaluating the binding energy value. Inhibition of tyrosinase is one way to inhibit the formation of melanin, so the skin becomes brighter. Spectrophotometry method was conducted to measure the absorbance of dopachrome and calculate the percentage of tyrosinase inhibition to be altered as IC50. Results: The energy values ​​of catechin and kojic acid in tyrosinase enzymes were -7.64 kcal/mol and -5.03 kcal/mol, respectively. The energy value of the catechin bond was smaller than kojic acid in the tyrosinase. The bond energy value showed that catechin had greater potential than kojic acid as a skin lightening agent by inhibiting tyrosinase in silico using the molecular docking method. The IC50 value from ethyl acetate extract of avocado seeds disrupt the tyrosinase using the in vitro test was 93.02 ± 1.98 mg/mL, while IC50 kojic acid was 48.67 ± 0.1 mg/mL. Conclusions: Avocado seeds extract containing catechin has a potential activity as a lightening agent by inhibiting the tyrosinase. Further research must be done to fractionation the extract to get a significant effect.

EFEKTIVITAS EKSTRAK BUAH LADA HITAM (PIPER NIGRUM L) KOMBINASI JAHE MERAH (ZINGIBER OFFICINALE) UNTUK MENGOBATI PENYAKIT VITILIGO

Vitiligo is a disease that causes skin color fading caused by cells that form melanin unfunctionally. The initial symptom is the appearance of white patches that will gradually become brighter and wider. Black pepper, aside from being used as a complement to cooking spices, its piperin content can stimulate the formation of skin melanin. Red Ginger is also believed to heal bad cells in the skin or restore damaged skin naturally, eliminating vitiligo because it contains collagen. This research used the experimental method. Data collection included pH test, organoleptic test, cream effectiveness test and pharmaceutical test. Data analysis used the Anova One Way to find out whether differences cream composition affected color, texture, thickness, and fondness. Test of T-Paired was used to determine differences vitiligo exposure before and after treatment. The comparison of Black Pepper: Red Ginger: Emulgade were (1:2:1), (1:1:1), (1:1:2), (1:1:3), and (1:3:8). Anova One Way test results showed that F-count to cream color (24,718)> F-table (4.53), F-count to cream texture (11,834)>F-table (4.53), F-count to cream density (15,001)>F-table (4.53) and F-count to cream fondness (6,517)>F-table (4.53). This showed that there was a significant difference for the combination of red ginger black pepper cream on color, texture, density and fondness on the cream. The effectiveness test of cream used T-paired test with result Tcount (5.277)>T-table (2.131), it showed that there was a significant difference in the vitiligo exposure before and after being given a cream of black pepper and red ginger. Pharmaceutical test explained that cream were homogeneous, semi-solid, had a distinctive odor, brownish yellow color, pH 6, and had a spread capacity of 5.2 cm.

Anti-melanogenic activity of salacinol by inhibition of tyrosinase oligosaccharide processing.

Hyperpigmentation that manifests through melasma and solar lentigo (age spots), although mostly harmless for health, bothers many people. Controlling the rate-limiting activity of tyrosinase is most effective for suppressing excessive melanin formation and accordingly recent research has focused on the maturation of tyrosinase. Salacia, a medicinal plant, has been used to treat diabetes in India and Sri Lanka. Salacia extract reportedly contains components that inhibit the activity of α-glucosidase. Salacinol, the active ingredient in Salacia extract, has unique thiosugar sulphonium sulphate inner salt structure. Here, we observed that the salacinol component of Salacia extract possesses anti-melanogenic activity in comparison to various existing whitening agents. Although the anti-melanogenic mechanism of salacinol is presumably medicated by inhibition of tyrosinase activity, which is often found in existing whitening agents, salacinol did not inhibit tyrosinase activity in vitro. Analysis of the intracellular state of tyrosinase showed a decrease in the mature tyrosinase form due to inhibition of N-linked oligosaccharide processing. Salacinol inhibited the processing glucosidase I/II, which are involved in the initial stage of N-linked glycosylation. Owing to high activity, low cytotoxicity and high hydrophilicity, salacinol is a promising candidate compound in whitening agents aimed for external application on skin.

Characterization and formulation of sunscreen from seaweed Padina australis and Euchema cottonii slurry

Exposure of UV light can cause skin rashes and sunburn, stimulating the formation of melanin. Long term UV exposure also can cause skin cancer. One way that can reduce negative impact of UV exposure is by using sunscreen. The aims of this study were to obtained the best ratio of seaweed P. australis and E. cottonii slurry to produce sunscreen cream and as well as obtaining sunscreen formulation with good stability. Creams were formulated consist of cream with different ratio of seaweed P. autralis and E. cottonii slurry, i.e. A (control), B (1:1), C (2:1) and D (1:2). The commercial creams product also used as a comparator (KI and KII). The best ratio of P. australis and E. cottonii slurry was showed on cream B (1:1). Sunscreen creams have a good level stability, with no phase separation of dispersant and dispersed phase, and also no discoloration. Sunscreen creams have at least 1 year shelf life as there was no phase separation after centrifugal force at 3,800 rpm for 5 hours.

Shrunk and scattered black spots turn out due to MC1R knockout in a white-black Oujiang color common carp (Cyprinus carpio var. color)

In teleosts, the chromatophore distribution pattern could result in their skin countershading. Previous observations suggested that Melanocortin receptor-1 (MC1R) plays roles in melanin modulation and their patterning processes in many mammals and some fish species. Using CRISPR-Cas9 techniques, we engineered the seven-transmembrane MC1R knockout mutants in Oujiang color common carp to test the hypothesis that the gene might have a role in melanogenesis in this fish. The loss-of-function (MC1R) fishes lost normal melanophore production and their subsequent growth, even while exposed in sunlight for a long time. The usual pathway of melanogenesis in white and black (WB) color carps was altered by this process. Deletion, substitution, and insertions were noticed and frameshift mutation was obtained. Disruptions in a shorter (10 bp–30 bp) fragment produced shrunken and underdeveloped melanophores on the fish skin instead of black patches and the mutant fishes appeared as grayish in color; and a higher rate of modification (215 bp deletion) resulted in remarkable reduction in melanin formation on the skin, and the albinic skin with quite shrunken melanophores appeared. Our present study found that a disruption in MC1R could change the formation pattern of black patches, which suggested that MC1R plays an important role in melanogenesis in Oujiang color common carp. Further evaluation of the relative expression level of some associated genes on the skin of both wild type and mutants can draw a clear scenario of MC1R pathways in melanogenesis in Oujiang color common carp.

The influence of morphological distribution of melanin on parameter selection in laser thermotherapy for vascular skin diseases.

Port wine stains (PWSs) are congenital vascular malformations that progressively darken and thicken with age. Currently, laser therapy is the most effective way in clinical management of PWS. It is known that skin pigmentation (melanin content) affects the radiant exposure that can be safely applied to treat PWS. However, the effect of melanin distribution in the epidermis on the maximum safe radiant exposure has not been studied previously. In this study, 10 different morphological distributions of melanin were proposed according to the formation and migration characteristics of melanin, and the two-scale heat transfer model was employed to investigate the influence of melanin distribution on the threshold radiant exposure of epidermis and blood vessels. The results show that melanin distributions do have a strong effect on laser parameter selection. When uniform melanin distribution is assumed, the threshold radiant exposure to damage a typical PWS blood vessel (50μm diameter) is 8.62J/cm2 lower than that to injure epidermis. The optimal pulse duration is 1-5ms for a typical PWS blood vessel of 50μm when melanin distribution is taken into consideration. PWS blood vessels covered by non-uniformly distributed melanin are more likely to have poor response to laser treatment.