Formation of Natural Melanin/TiO_(2) Nanostructure Hybrids with Enhanced Optical,Thermal and Magnetic Properties as a Soft Material

The natural Melanin/TiO_(2) was synthesized by the use of ultrasonication under UV radiation.The influence of natural melanin on the structural,optical and thermal properties of TiO_(2) nanoparticles was investigated by using Fourier transform infrared spectroscopy,thermogravimetric analysis and UV-Vis spectroscopy.It was observed that incorporating natural melanin on TiO_(2) nanoparticles(TiO_(2)-Mel)occurred at 2.01 eV with a low value of Urbach energy around 100 meV indicating improvement in the crystalline structure.Magnetic measurement at room temperature showed diamagnetic behavior.Furthermore,thermal results showed that TiO_(2)-Mel is stable even at temperatures up to 400℃.According to the results obtained by the thermal stability of melanin with titanium dioxide,it can be a good candidate in many applications such as solar cells and optoelectronics.

Inhibition of tyrosinase activity and melanine pigmentation by 2-hydroxytyrosol

2-Hydroxytyrosol(2-HT),originally reported as a synthetic compound,was isolated for the first time as a fungal metabolite.2-HT was found to inhibit mushroom tyrosinase with an IC_(50) value of 13.0 mmol/L.Furthermore,2-HT dose-dependently inhibited tyrosinase activity(IC_(50),32.5 mmol/L)in the cell-free extract of B16 melanoma cells andα-melanocyte stimulating hormone(α-MSH)-stimulated melanin formation in intact B16 melanoma cells.

Pigment Distribution and Secretion in the Mantle of the Pacific Oyster(Crassostrea gigas)

The color of Mollusca shells is one of the most important attributes to consumers.At the cellular level,black color is mainly from the melanin produced by melanocytes.The melanosome is a specialized membrane-bound organelle that is involved in melanin synthesis,storage,and transportation.How the complex pigmentation process in the Crassostrea gigas is established remains an open question.The objectives of this studies are to examine the morphological characteristics of melanosomes or melanin of mantle pigmentation in the Pacific oyster,thereby investigating its contribution to shell color.The results show that pigmented granules of the mantles vary among the three lobes,and the melanosomes at different stages are enriched in distinct cargo molecules,which indicate the remarkable difference between the marginal mantle and central mantle.Examination of mantle histology reveals that the mantle margin of the oyster is characterized by three different folds,including the outer secretory,middle sensory,and inner muscular fold.Ferrous ion chelating assays against the tyrosine hydroxylase indicate that a large amount of melanin is localized in the inner surface of the middle fold.Transmission electron microscopy analyses show that the mantle edge is composed of tall columnar and cuboidal epidermal cells and some pigmented melanocytes intersperse among these cells.The numbers of melanosomes among the three lobes are different.In the inner fold and the middle fold of the mantle,some single dispersion,or aggregation of melanosomes with different degrees of melanization are found in the outer surface.Numerous melanosomes are distributed in the epithelium of the outer fold of the mantle,and mainly are at the apical microvillar surface near the lumen.However,melanosomes are occasionally observed in the central mantle,and they are relatively less.This work provides new insights into the process of melanin deposit in the mantle and shell pigmentation in C.gigas.

Dietary aflatoxin B1 induces abnormal deposition of melanin in the corium layer of the chicken shank possibly via promoting the expression of melanin synthesis-related genes

San-Huang chicken is a high-quality breed in China with yellow feather, claw and break. However, the abnormal phenomenon of the yellow shank turning into green shank of San-Huang chicken has been a concern, as it seriously reduces the carcass quality and economic benefit of yellow-feathered broilers. In this study, the cause of this abnormal green skin in shank was systematically investigated. Physiological anatomy revealed that the abnormal skin in shank was primarily due to the deposition of melanin under the dermis. After analyzing multiple potential causes such as heredity(pedigree and genetic markers), environment(water quality monitoring) and feed composition(mycotoxin detection), excessive aflatoxin B1(AFB1) in feed was screened, accompanied with a higher L-dihydroxy-phenylalanine(L-DOPA)(P<0.05) and melanin content(P<0.01). So it was speculated that excessive AFB1 might be the main cause of abnormal green skin in shank. Subsequently, the further results showed that a high concentration of AFB1(>170 μg kg–1)indeed induced the abnormal green skin in shank compared to the normal AFB1 content(<10 μg kg–1), and the mRNA levels of TYR, TYRP1, MITE, MC1R and EDN3 genes related to melanin deposition would significantly up-regulate(P<0.01) and the content and activity of tyrosinase(TyR) significantly increased(P<0.05). At the same time, the content of L-DOPA and melanin deposition also increased significantly(P<0.01), which also confirmed the effect of excessive AFB1 on melanin deposition in skin of shank. Results of additional experiments revealed that the AFB1's negative effect on melanin deposition in skin of shank could last for a longer time. Taken together, the results of this study explained the occurrence and possible mechanisms of the abnormal AFB1-related green skin in shank of chickens. Excessive AFB1 in diets increased the L-DOPA content and melanin abnormal deposition in the chicken shank possibly via promoting TyR content and activity, and the expression of melanin synthesis-related genes. Furthermore, our findings once again raised the alarm of the danger of AFB1 in the broiler production.

Pharmacodynamics of frigid zone plant Taxus cuspidata S.et Z.against skin melanin deposition,oxidation,inflammation and allergy

Background:Taxus cuspidata S.et Z.is a precious species of frigid zone plant belonging to the Taxaceae family,which possesses anticancer,anti-inflammatory,hypoglycemic,and antibacterial pharmacological properties.While taxane extracted from Taxus chinensis has been reported to elicit antioxidant activities,whether Taxus cuspidata S.et Z.has skin-protective actions against injuries remained unknown.This study aims to explore the pharmacological effects of three Taxus extracts on skin melanin deposition,oxidation,inflammation,and allergy so as to provide new ideas for the prevention and treatment of various diseases related to skin damage.Methods:Skin melanin deposition was evaluated by measuring melanin content in the skin of guinea pigs by alkali lysis method.Antioxidant capacity was evaluated by measuring superoxide dismutase(SOD)concentration and glutathione(GSH)content in skin tissue homogenates of Kunming mice by SOD assay kit and micro reduced GSH assay kit.The quantitative real-time polymerase chain reaction(qRT-PCR)and western blotting were used to examine the levels of both SOD and recombinant glutathione peroxidase 4(GPX4).Skin inflammation was evaluated by xylene-induced ear swelling test and egg-white-induced paw swelling test in mice.In a mouse model of skin allergy induced by 4-aminopyridine(4-AP),allergy was determined by licking body counts and histamine concentrations in tissue homogenates using enzyme-linked immunosorbent assay(ELISA)kits.Two proinflammatory factors tumor necrosis factor(TNF)-αand interleukin(IL)-1βwere measured by qRT-PCR.Hematoxylin and eosin(HE)staining was conducted to assess the degree of skin lesion.Results:All three Taxus extracts including Taxus chinensis essential oil,Taxus chinensis extract and Taxus chinensis extract compound reduced the melanin deposits in the back skin relative to the non-treated control animals,of which Taxus chinensis essential oil produced the greatest effect.In contrast,the three Taxus extracts elevated SOD and GSH levels in the skin tissues,and the highest increase was seen with Taxus chinensis essential oil.Three Taxus extracts,especially Taxus chinensis essential oil,effectively reduce the rate of ear and paw swelling.All three Taxus extracts reduced the number of body licks,the levels of TNF-αand IL-1β,and the histamine content in tissue homogenates of mice and alleviated skin damage.Consistently,Taxus chinensis essential oil yielded the greatest magnitude of decreases.Conclusion:While all three Taxus extracts possessed the anti-skin melanin deposition,oxidation,and allergy properties,Taxus chinensis essential oil produced the superior effects.

Study on The Whitening Effect of a Composite Plant Extract

By compounding the cranberry extract,lavender flower extract,Kakadu plum extract,edelweiss flower/leaf extract and aloe vera extract into a composite plant extract(BIRC-Rosée WT100),the whitening effects of this composite plant extract in antioxidation,anti-inflammation,skin barrier maintenance,and inhibition of melanin production and transport were evaluated.By comparing the inhibitory effects on tyrosinase activity between the composite plant extract andα-arbutin,and then analyzing the decline of apparent chromaticity,apparent brightness and melanin content through 3D melanin skin model platform,the comprehensive whitening effect was evaluated and compared with that of kojic acid.The results showed that,the composite plant extract(BIRC-Rosée WT100)had a tyrosinase inhibition rate of 98.99%at the original concentration,which was much higher than that ofα-arbutin.In 3D melanin skin model,the apparent chromaticity and brightness could be effectively improved,and moreover,the total amount of melanin in the skin could be reduced,showing remarkable whitening effect.

脑膜黑色素细胞瘤

脑膜黑色素细胞瘤是一种源于软脑膜黑色素细胞,组织学形态分化良好,呈实性、非浸润性的黑色素细胞瘤,是一种孤立性、不伴周围组织浸润的低级别肿瘤。组织学形态特征性表现为上皮样、纺锤形、多形或梭形黑色素细胞,无间变、坏死,核分裂象少见;梭形或椭圆形肿瘤细胞内含有数目不等的黑色素,呈紧密巢状,类似脑膜瘤＂漩涡＂样结构（图1a）.

Down-regulation of tyrosinase,TRP-1,TRP-2 and MITF expressions by citrus press-cakes in murine B16 F10 melanoma

Objective:To investigate the suitability of citrus-press cakes,by-products of the juice industry as a source for the whitening agents for cosmetic industry.Methods:Ethylacetate extracts of citrus-press cakes(CCE)were examined for their anti-melanogenic potentials in terms of the inhibition of melanin production and mechanisim of melanogenesis by using Western Blot analysis with tyrosinese,tyrosinase-related protein-1(TRP-1),TRP2,and microphthalmia-associated transcription factor(MITF)proteins.To apply the topical agents,citrus-press cakes was investigated the safety in human skin cell line.Finally flavonoid analysis of CCE was also determined by HPLC analysis.Results:Results indicated that CCE were shown to down-regulate melanin content in a dose-dependent pattern.The CCE inhibited tyrosinase,TRP-2,and MITF expressions in a dose-dependent manner.To test the applicability of CCE to human skin,we used MTT assay to assess the cytotoxic effects of CCE on human keratinocyte HaCaT cells.The CCE exhibited low cytotoxicity at 50μg/mL.Characterization of the citrus-press cakes for flavonoid contents using HPLC showed varied quantity of rutin,narirutin,and hesperidin.Conclusions:Considering the anti-melanogenic activity and human safety,CCE is considered as a potential anti-melanogenic agent and may be effective for topical application for treating hyperpigmentation disorders.

Therapeutic effect of natural melanin from edible fungus Auricularia auricula on alcohol-induced liver damage in vitro and in vivo

This study explored the therapeutic effects of Auricularia auricula melanin(AAM)on alcoholic liver damage in vitro and in vivo.Human normal liver L02 cells were pre-treated with ethanol and then treated with AAM to explore the therapeutic effect of AAM on ethanol-induced hepatocyte injury.The results show that AAM signifi cantly elevated the cell viability,ameliorated the cell morphology,reduced the ROS and increased the GSH/GSSG of ethanol-pretreated L02 cells.Then,mice were administered with ethanol to induce acute alcoholic liver damage,and administered with AAM to further study the therapeutic effect of AAM on alcoholic liver damage in mice.As a result,AAM reduced the levels of ALT,AST,TG,and MDA,increased the levels of ADH,SOD,and CAT in liver damage mice.The therapeutic effect of AAM may be related to inhibition of CYP2E1 expression and activation of Nrf2 and its downstream antioxidase.The research enriched the bioactivity of AAM and provided some ideas for the development of melanin-related health foods.

Isolation of Stenotrophomonas maltophilia from clinical samples: An investigation of patterns motility and production of melanin pigment

Objectives: To investigate possible sources of Stenotrophomonas maltophilia(S. maltophilia) in the clinical environment.Methods: Different samples were collected from Amol City of Iran. Steps for the identification of S. maltophilia included culturing, biochemical tests, polymerase chain reaction(PCR) of 16 S r RNA gene and 23 S r RNA gene. In addition, production of melanin pigment and patterns of motility of the bacteria, were also investigated.Results: In our study, 20 S. maltophilia strains were isolated from clinical sources,oxygen manometer apparatus of hospitals were 7/110(6.36%), blood was 1/777(0.13%),sputum was 4/40(4%), urine was 1/2 947(0.03%), tap water was 1/240(0.42%) and dental suction was 6/120(5%). The isolated bacteria showed production of melanin pigment with rates of strong, moderate, weak, and lack of pigment. Types of motilities were seen in isolates.Conclusions: The highest percentage of bacteria is isolated of oxygen manometer system and dental suction, yet has not been reported from oxygen manometer system. These bacteria have also been associated with patients who have respiratory problems, so it is essential for staffs of hospitals to draw attention to this source of bacteria.

The leaf extract of Mallotus japonicus and its major active constituent, rutin,suppressed on melanin production in murine B16F1 melanoma

Objective: To find anti-melanogenesis materials used in whitening cosmetics.Methods: The ethanolic leaf extract of Mallotus japonicus(M. japonicus) having an anti-melanogenesis activity was separated by a sephadex LH-20 chromatography. Each fraction was measured for its tyrosinase inhibitory activity together with its polyphenol content using the Folin–Ciocalteu method. The anti-melanogenesis activity of the active fractions was determined by the melanin content in the murine B16F1 melanoma. The active fractions were put together due to similar constituents, and then separated by high performance liquid chromatography using a C-18 ODS column. The major antimelanogenesis compound was identified using1 H and13C-NMR and liquid chromatography-mass spectrometry.Results: The ethanolic leaf extract of M. japonicus showed an anti-tyrosinase activity with a high polyphenol content, resulting in suppression of melanin production in the B16F1 melanoma. The extract was separated and the active compound was identical as rutin based on the1 H,13C-NMR and liquid chromatography-mass spectrometry analysis data. In addition, the rutin treatment with cells reduced the melanin content in a concentration dependent manner without any cell toxicity. The leaf extract of M. japonicus containing rutin would be useful in whitening cosmetics for protection from UV-light exposure to be limiting the accumulation of melanin in skin.Conclusions: The leaf extract of M. japonicus and/or rutin isolated from the extract as a key whitening agent would be useful as a whitening cosmetic material for protecting against disorder skin due to melanin accumulation.

Catalysis-based specific detection and inhibition of tyrosinase and their application

Tyrosinase is an important enzyme in controlling the formation of melanin in melanosome,and plays a key role in the pigmentation of hair and skin.The abnormal expression or activation of tyrosinase is associated with several diseases such as albinism,vitiligo,melanoma and Parkinson disease.Excessive deposition of melanin could cause diseases such as freckles and brown spots in the human body,and it is also closely related to browning of fruits and vegetables and insect molting.Detecting and inhibiting the activity of tyrosinase is of extraordinary value in the progress of diagnosis and treatment of these diseases.Therefore,many selective optical detection probes and small molecular inhibitors have been developed,and have made significant contributions to the basic and clinical research on these diseases.In this paper,the detection and inhibition of tyrosinase and their application in whitening products are reviewed,with special emphasis on development of fluorescent probes and inhibitors.Hopefully,this review will help design more efficient and sensitive tyrosinase probes and inhibitors,as well as shed light on novel treatment of diseases such as melanoma.

UPLC-MS metabolomics provides insights into the diff erences between black- and white-shelled Pacifi c oysters Crassostrea gigas

A variety of shell colors are one of the most fundamental characteristics of molluscs,which have importantly ecological and economic signifi cance.The Pacifi c oyster Crassostrea gigas is distributed in many sea areas around the world and also an aquacultured mollusc with high nutritional value.In this study,the whole soft body and the mantle tissue of black-shelled Pacifi c oyster(BSO)and white-shelled Pacifi c oyster(WSO)with starkly diff erent melanin contents were compared,and the diff erences in physiology and metabolism between BSO and WSO were analyzed.The results of physiological indicators suggested BSO show more melanin,more dry matter,more crude lipid content,and stronger ability to scavenge free radicals than WSO.The altered metabolites of glycerophospholipids,fatty acyls,and steroids revealed diff erent regulatory mechanisms of lipids.The correlation analysis of metabolomics and previously published RNAseq data suggested that BSO and WSO mainly diff ered in the basal metabolic processes,such as lipid,amino acid and purine metabolisms.This study provides insights into the changes in the physiological indictors and the metabolites of oysters with varying melanin content.

Extraction and Purification of Depigmenting Agents from Chinese Plants

Depigmenting agents were solvent-extracted and purified by preparative and analytical HPLC from three Chinese plants; Chrysanthemum morifolium Ramat（ Xizang Caijuhua）, Rhodiola sachalinensis, and Terminalia chebula Retzius. Four fractions obtained from the ethyl ether layer of C. m. Rama and two fractions from the ethyl acetate layer of Rhodiola salientness show depigmenting effects. At 8 200, the ethyl acetate layers of Chrysanthemum morifolium Ramat, Rhodiola sachalinensis and the methanol extract of Terminalia chebula Retzius, can inhibit the melanin production of mouse B16 melanoma cells by 92%, 60% and 90%, respectively, whereas 46% inhibition was observed by commercially available depigmenting agents（arbutin）. These results show the potential of these three Chinese plants as a novel resource for depigmenting agents in the cosmetic industry.

Sensitivity Detection Technique and Resistance Risk Assessment of Magnaporthe grisea to Tricyclazole

In vitro detection method for the sensitivity of Magnaporthe grisea to tricyclazole was studied, and the potential resistance risk of blast disease to tricyclazole was assessed. Both EC50 of hyphal melanization (EC50-H) and minimum inhibitive concentration of melanization in appressorial (MIC-A) by inhibitor tricyclazole showed positive correlation to the EC50 of tricyclazole against blast disease tested in vivo, with relative co-efficiency (R5) of 0.8995 and 0.8244, respectively. However, stability and reproducibility of EC50-H were better than those of MIC-A, suggesting that it could be used to detect the sensitivity of M. grisea to tricyclazole in vitro. Tricyclazole sensitivity of the progenies derived from single spores of the most sensitive isolate DY2 and the least sensitive isolate GY6 detected in sensitivity monitoring in 2000 was not stable, with mean EC50 values of 4.4968 μg/mL and 5.4010 ug/mL, respectively, indicating that the difference in EC50 between DY2 and GY6 was not caused probably by resistance variation. EC50 of GY6 did not increase significantly when continuously selected for twenty generations under the selection pressure of tricyclazole in vivo. However, the sensitivity of DY2 was decreased by 10-fold after selected for twenty generations. The results suggested that tricyclazole was still low resistance risk for M. grisea in China.

XPS and FTIR studies of fungus-stained Daemonorops margaritae

We explored the discoloration of rattan cane using X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared spectroscopy(FTIR). XPS analysis showed that after the cane was stained by Lasiodiplodia theobromae, carbon and oxygen elements and the ratio of oxygen to carbon decreased. Considering atomic binding,C_1 and C_4 contents increased, while C_2 and C_3 contents decreased, and the ratio of O_2 to O_1 decreased sharply. The relative contents of lignin, cellulose and polysaccharides increased and new substances with low O_2/O_1 ratio occurred. FTIR analysis showed that the absorption peaks of O–H at 3346 cm^(-1), aliphatic C–H at 2921, 2853 and1464 cm^(-1), and C=O at 1723 cm^(-1), were characteristic peaks of fungal melanin intensified, indicating that cane discoloration was primarily caused by fungal melanin. The absorption peaks characterizing cellulose and lignin like polysaccharides at 800 cm^(-1), C–H at 1374 cm^(-1), C–O at1058 and 1038 cm^(-1), phenolic hydroxyl at 1245 cm^(-1),aromatic ether bonds at 1270 cm^(-1), carbon skeleton at1608 cm^(-1) and benzene ring at 1500 cm^(-1) were enhanced since the fungus mainly consumed the extractives in cane cell lumens and the main composition content increased relatively. Regardless of the discoloration caused by natural fungi or inoculated fungi, the discoloring feature and composition changes were identical except that the fungusinoculated cane had more melanin.

Mushroom Tyrosinase Inhibition and Antimelanogenesis Activities of <i>Bacopa monnieri</i>(L.) Methanol Extract in B16F10 Melanoma Cells

Melanocytes that form stratum basale of skin epidermis express tyrosinase enzyme, which catalyzes initial two rate-limiting steps in the biotransformation of tyrosine into dark pigment called melanin. Even today, Tyrosinase inhibitors are among the promising candidates in cosmetic industry for skin-lightening formulations. Overexpression of tyrosinase causes excess melanin biosynthesis and deposition resulting in dark skin color. Moreover, localized overexpression of tyrosinase cause variety of hyperpigmentation disorders like melanoma, melasma, chloasma, dark patches, liver patches, etc. There has been a renewed interest in the natural products as main ingredients in the formulation of safe products for skin-whitening and treatment options for hyperpigmentation disorders. In the present communication, the results of our investigations on tyrosinase inhibition, modulation of intracellular tyrosinase and melanin levels in cultured B16F10 melanoma cells by Bacopa monnieri (L.) methanol extract (BME) are presented and discussed as safe option for skin lightening and to treat hyperpigmentation disorders. BME showed 11%, 29%, 54% and 80% inhibition of mushroom tyrosinase activity at an initial 100, 200, 400 and 600 μg of extract. Treatment of α-melanocyte stimulating hormone (α-MSH) stimulated cultured murine melanoma B16F10 cells with 100 μg/ml of the extract showed a decrease in the levels of cellular melanin and cellular tyrosinase content by 22% and 46% respectively. The cytotoxicity studies by MTT assay revealed that the LC50 of the BME is ≥1000 μg/ml in cultured mouse melanoma B16F10 and HEK293 cells.

Phyllanthus acidus(L.) Skeels and Rhinacanthus nasutus(L.) Kurz leaf extracts suppress melanogenesis in normal human epidermal melanocytes and reconstitutive skin culture

Objective: To determine the effect of extracts from Phyllanthus acidus(P. acidus)(L.) Skeels and Rhinacanthus nasutus(R. nasutus)(L.) Kurz leaves on melanogenesis and the underlying mechanism in normal human epidermal melanocytes(NHEM) and a reconstitutive skin model. Methods: NHEM and a reconstitutive skin model were stimulated with ethanol extracts of P. acidus(L.) Skeels and R. nasutus(L.) Kurz leaves. mRNA expression of microphthalmiaassociated transcription factor(MITF), tyrosinase(TYR), tyrosinase-related protein 1(TYRP1) and dopachrome tautomerase(DCT) were examined by real-time PCR. The melanin content in NHEM was also measured. Moreover, protein levels of tyrosinase were determined using western blot analysis.Results: In NHEM and the reconstitutive skin model, ethanol extracts from P. acidus(at 12.5 and 25.0 μg/mL) and R. nasutus(at 6.25 and 12.50 μg/mL) significantly diminished mRNA expression of MITF, TYR, TYRP1 and DCT in a concentration-dependent manner. P. acidus and R. nasutus extracts also reduced the amount of melanin in α-MSH-stimulated NHEM. Moreover, P. acidus and R. nasutus extracts markedly suppressed tyrosinase at the translational level in the reconstitutive skin model. Conclusions: P. acidus and R. nasutus extracts significantly reduced melanogenesis in NHEM and the reconstitutive skin model, suggesting that P. acidus and R. nasutus extracts can inhibit melanin synthesis through downregulation of MITF, TYR, TYRP1 and DCT. Therefore, the ethanol extracts of P. acidus and R. nasutus contain compounds that have the potential for development as a skin lightening agent for the treatment of hyperpigmentation disorder or melasma.

Bacterial melanin promotes recovery after sciatic nerve injury in rats

Bacterial melanin, obtained from the mutant strain of Bacillus Thuringiensis, has been shown to promote recovery after central nervous system injury. It is hypothesized, in this study, that bacterial melanin can promote structural and functional recovery after peripheral nerve injury. Rats subjected to sciatic nerve transection were intramuscularly administered bacterial melanin. The sciatic nerve transected rats that did not receive intramuscular administration of bacterial melanin served as controls. Behavior tests showed that compared to control rats, the time taken for instrumental conditioned reflex recovery was significantly shorter and the ability to keep the balance on the rotating bar was significantly better in bacterial melanin-treated rats. Histomor- phological tests showed that bacterial melanin promoted axon regeneration after sciatic nerve injury. These findings suggest that bacterial melanin exhibits neuroprotective effects on injured sciatic nerve, contributes to limb motor function recovery, and therefore can be used for rehabil- itation treatment of peripheral nerve injury.

Biomedical overview of melanin.1.Updating melanin biology and chemistry,physico-chemical properties,melanoma tumors,and photothermal therapy

Melanins(eumelanin,pheomelanin,and allomelanin)represent a very,if not themost,important group of biological pigments.Their biological roles are multiple,from photoprotection to antioxidant activity,heavy metal disposal or the myriad uses of color in organisms across all Phyla.In the first part of this review,eumelanin biology and some chemical aspects will be presented,as well as key physico-chemical features that make this biological pigment so interesting.The principal characteristics of the melanocyte,the melanin-synthesizing cell in mammals,will also be introduced.Transformed melanocytes are the cause of one of the most devastating known cancers:the malignant melanoma.Epidemiology and molecular signaling aspects will be presented next,as well as the principal advances in promising oncotherapies designed and applied for the treatment of melanoma.In particular,on account of the photo-physical properties of melanin,special details will be provided regarding the use of photothermal therapy for melanoma treatment.