Melanin Inhibitory Effect of Tuber himalayense Isolated in Incheon, Korea.

There has been a growing interest in skin beauty and antimelanogenic products. Melanogenesis is the process of melanin synthesis whereby melanocytes are activated by UV light or hormone stimulation to produce melanin. Melanogenesis is mediated by several enzymes, such as tyrosinase (TYR), microphthalmia-associated transcription factor (MITF), tyrosinase-related protein-1 (TRP-1), and TRP-2. In this study, we investigated the effect of Tuber himalayense extract on melanin synthesis in α-melanocyte-stimulating hormone (α-MSH)-treated B16F10 melanoma cells. We confirmed that T. himalayense extract was not toxic to α-MSH-treated B16F10 melanoma cells and exhibited a significant inhibitory effect on melanin synthesis at concentrations of 25, 50, and 100 µg/ml. Additionally, the T. himalayense extract inhibited melanin, TRP-1, TRP-2, tyrosinase, and MITF, which are enzymes involved in melanin synthesis, in a concentration-dependent manner. Furthermore, T. himalayense extract inhibited the mitogen-activated protein kinase (MAPK) pathways, such as extracellular signal-regulated kinase-1/2 (ERK), c-Jun N-terminal kinase (JNK), and p38. Therefore, we hypothesized that various components of T. himalayense extract affect multiple factors involved in melanogenesis in B16F10 cells. Our results indicate that T. himalayense extract could potentially be used as a new material for preparing whitening cosmetics.

Cajanin Suppresses Melanin Synthesis through Modulating MITF in Human Melanin-Producing Cells.

Despite its classification as a non-life-threatening disease, increased skin pigmentation adversely affects quality of life and leads to loss of self-confidence. Until now, there are no recommended remedies with high efficacy and human safety for hyperpigmentation. This study aimed to investigate anti-melanogenic activity and underlying mechanism of cajanin, an isoflavonoid extracted from Dalbergia parviflora Roxb. (Leguminosae) in human melanin-producing cells. Culture with 50 µM cajanin for 48-72 h significantly suppressed proliferation in human melanoma MNT1 cells assessed via MTT viability assay. Interestingly, cajanin also efficiently diminished melanin content in MNT1 cells with the half maximum inhibitory concentration (IC50) at 77.47 ± 9.28 µM. Instead of direct inactivating enzymatic function of human tyrosinase, down-regulated mRNA and protein expression levels of MITF and downstream melanogenic enzymes, including tyrosinase, TRP-1 and Dct (TRP-2) were observed in MNT1 cells treated with 50 µM cajanin for 24-72 h. Correspondingly, treatment with cajanin modulated the signaling pathway of CREB and ERK which both regulate MITF expression level. Targeted suppression on MITF-related proteins in human melanin-producing cells strengthens the potential development of cajanin as an effective treatment for human hyperpigmented disorders.

Melanogenesis-promoting effect of Cirsium japonicum flower extract in vitro and ex vivo.

OBJECTIVE: In this study, we examined the effect of C. japonicum flower extract (CFE) on melanogenesis and its mechanism in vitro and ex vivo. METHODS: The effect of CFE on melanogenesis was investigated with lightly (HEMn-LP) and moderately (HEMn-MP) pigmented normal human melanocytes, reconstituted three-dimensional skin (3D skin) model and ex vivo human hair follicles. The melanogenesis-inducing effect of CFE was evaluated using melanin content and intracellular tyrosinase activity assay. The amount and type of eumelanin and pheomelanin were analysed by using HPLC method. The mechanism involved in the effect of CFE on hyperpigmentation was explored by cyclic adenosine monophosphate (cAMP) immunoassay and western blot analysis for tyrosinase, microphthalmia-associated transcription factor (MITF) and phosphorylated CRE-binding protein (pCREB) expression. The degree of pigmentation in 3D skin and L-values were measured using a CR-300 chroma meter. The amount of dissolved melanin was measured using a spectrophotometer. The content of melanin in the hair follicles was evaluated by Fontana Masson staining. RESULTS: C. japonicum flower extract significantly increased the melanin content and cellular tyrosinase activity in both HEMn-LP and HEMn-MP cells. The markers of pheomelanin and eumelanin in HEMn-LP and HEMn-MP were also increased by CFE. We observed that CFE treatment on melanocytes increased intracellular cAMP with inducing pCREB and up-regulating the protein levels of TYR and MITF. Furthermore, CFE considerably increased the melanin content in a 3D skin model and ex vivo human hair follicles. CONCLUSIONS: These results suggest that CFE exerts hyperpigmentation activity through cAMP signalling in human melanocytes that it can improve follicular depigmentation and vitiligo by stimulating the melanin synthesis.

OBJECTIF: Dans cette étude, nous avons examiné l'effet de l'extrait de fleur de C. japonicum (EFC) sur la mélanogenèse et son mécanisme in vitro et ex vivo. MÉTHODES: L'effet du EFC sur la mélanogenèse a été étudié avec des mélanocytes humains normaux légèrement (HEMn-LP) et modérément (HEMn-MP) pigmentés, un modèle de peau reconstituée en 3 dimensions (peau 3D) et des follicules pileux ex vivo. L'effet inducteur de la mélanogénèse de la EFC a été évalué en utilisant la teneur en mélanine et le dosage de l'activité de la tyrosinase intracellulaire. La quantité et le type d'eumélanine et de phéomélanine ont été analysés en utilisant la méthode HPLC. Le mécanisme impliqué dans l'effet de la EFC sur l'hyperpigmentation a été exploré par immunoessai à l'adénosine monophosphate cyclique (AMPc) et Western blot pour l'expression de la tyrosinase, du facteur de transcription associé à la microphtalmie (MITF) et l'expression de la protéine CREB phosphorylée. Le degré de pigmentation de la peau 3D, les valeurs L ont été mesurées à l'aide d'un chromamètre CR-300. La quantité de mélanine dissoute a été mesurée à l'aide d'un spectrophotomètre. La teneur en mélanine des follicules pileux a été évaluée par coloration Fontana Masson. RÉSULTATS: EFC a augmenté de manière significative la teneur en mélanine et l'activité de la tyrosinase cellulaire dans les cellules HEMn-LP et HEMn-MP. Les marqueurs de phéomélanine et d'eumélanine dans HEMn-LP et HEMn-MP ont également été augmentés par EFC. Nous avons observé que le traitement EFC sur les mélanocytes augmentait l'AMPc intracellulaire en induisant pCREB et en régulant à la hausse les niveaux de protéines de TYR et MITF. De plus, le EFC a considérablement augmenté la teneur en mélanine dans un modèle de peau 3D et dans les follicules pileux humains ex vivo. CONCLUSIONS: Ces résultats suggèrent que la EFC exerce une activité d'hyperpigmentation via la signalisation de l'AMPc dans les mélanocytes humains qu'elle peut améliorer la dépigmentation folliculaire et le vitiligo en stimulant la synthèse de mélanine.

Salicylic acid in ginseng root alleviates skin hyperpigmentation disorders by inhibiting melanogenesis and melanosome transport.

Abnormal melanogenesis and melanosome transport can cause skin pigmentation disorders that are often treated using ginseng-based formulation. We previously found that phenolic acid compounds in ginseng root could inhibit melanin production and as a skin-whitening agents. However, mechanisms of action underlying effects of ginseng phenolic acid monomers on melanogenesis remain unclear. This study was conducted to investigate effects of salicylic acid, a main ginseng root phenolic acid component, on melanogenesis and melanosome functions in melanocytes of zebrafish and other species. Salicylic acid exhibited no cytotoxicity and reduced melanin levels and tyrosinase activity in B16F10 murine melanoma cells and normal human epidermal melanocytes regardless of prior cell stimulation with α-melanocyte stimulating hormone. Additionally, salicylic acid treatment reduced expression of melanogenic enzymes tyrosinase, tyrosinase-related protein 1 and tyrosinase-related protein 2, while reducing expression of their master transcriptional regulator, microphthalmia-associated transcription factor. Moreover, reduced phosphorylation of cAMP response-element binding protein was observed due to reduced cAMP levels resulting from salicylic acid inhibition of upstream signal regulators (adenylyl cyclase and protein kinase A). Furthermore, salicylic acid treatment suppressed expression of transport complex-associated proteins melanophilin and myosin Va in two UVB-treated melanocytic cell lines, suppressed phagocytosis of fluorescent microspheres by UVB-stimulated human keratinocytes (HaCaT), inhibited protease-activated receptor 2 activation by reducing both Ca2+ release and activation of phosphoinositide 3 kinase/AKT and mitogen-activated protein kinases and induced anti-melanogenic effects in zebrafish. Collectively, these results indicate that salicylic acid within ginseng root can inhibit melanocyte melanogenesis and melanin transport, while also suppressing keratinocyte phagocytic function.

Herb Sanqi-Derived Compound K Alleviates Oxidative Stress in Cultured Human Melanocytes and Improves Oxidative-Stress-Related Leukoderma in Guinea Pigs.

Sanqi, a traditional Chinese herb, is widely used for cardiovascular diseases, and its neuroprotective effects against oxidative stress were recently discovered. The purpose of this study was to investigate whether Sanqi-derived compound K (Sanqi-CK), an active metabolite of Sanqi, could protect melanocytes from oxidative stress. Cultured human primary skin epidermal melanocytes (HEMn-MPs) were treated with hydrogen peroxide (H2O2) in the presence or absence of Sanqi-CK. Sanqi-CK exhibited protective effects against H2O2-induced cell death by reducing oxidative stress. In addition, treatment with Sanqi-CK reversed the decreased glutathione reductase activity and decreased ratio of reduced glutathione (GSH)/oxidized glutathione (GSSG) seen in H2O2-treated melanocytes. Furthermore, topical application of Sanqi-CK alleviated leukoderma in guinea pigs, a disorder characterized by melanocyte cell death resulting from rhododendrol-induced oxidative stress. Taken together, these data suggest that Sanqi-CK protects melanocytes against oxidative stress, and its protective effects are associated with modulating the redox balance between GSH and GSSG and activating glutathione reductase. Thus, Sanqi-CK may be a good candidate for preventing melanocyte loss in oxidative-stress-associated pigmentary disorders.

MAPK and Notch-Mediated Effects of Meso-Xanthin F199 Compounds on Proliferative Activity and Apoptosis of Human Melanocytes in Three-Dimensional Culture.

Meso-Xanthin (Meso-Xanthin F199™) is a highly active antiaging injection drug of the latest generation. The main acting compound is fucoxanthin, supplemented with several growth factors, vitamins, and hyaluronic acid. Previous examination of fucoxanthin on melanocytes showed its ability to inhibit skin pigmentation through different signaling pathways focused on suppression of melanogenic-stimulating receptors. In turn, the anticancer property of fucoxanthin is realized through MAPK and PI3K pathways. We aimed to evaluate the effect of fucoxanthin and supplemented growth factors on melanocyte growth and transformation at a proteomic level. The effect of fucoxanthin on melanocytes cultivated in three-dimensional (3D) condition was examined using high-throughput proteomic and system biology approaches to disclose key molecular events of the targeted action. Our results demonstrated significant inhibition of cell differentiation and ubiquitination processes. We found that the negative regulation of PSME1 and PTGIS largely determines the inhibition of NF-κB and MAPK2. Besides, fucoxanthin selectively inhibits cell differentiation via negative regulation of Raf signaling and the upstream activation of IL-1 signaling. It is assumed that inhibition of Raf influences the Notch-4 signaling and switches off the MAPK/MAPK2 cascade. Blockage of MAPK/MAPK2 is feasible due to suppression of Ras and NF-κB by the addressed action of IKKB, IKK2, and TRAF6. Suggestively, Meso-Xanthin F199™ can manage processes of proliferative activity and inhibition of apoptosis due to composition of fucoxanthin and growth-stimulating factors, which may increase the risk of skin cancer development under certain condition.

Tropolone-Bearing Sesquiterpenes from Juniperus chinensis: Structures, Photochemistry and Bioactivity.

The tropolone-bearing sesquiterpenes juniperone A (1) and norjuniperone A (2) were isolated from the folk medicinal plant Juniperus chinensis, and their structures were determined by a combination of spectroscopic and crystallographic methods. Photojuniperones A1 (3) and A2 (4), bearing bicyclo[3,2,0]heptadienones derived from tropolone, were photochemically produced and structurally identified by spectroscopic methods. Predicted by the machine learning-based assay, 1 significantly inhibited the action of tyrosinase. The new compounds also inhibited lipid accumulation and enhanced the extracellular glycerol excretion.

Inhibitory Effect of Elaeagnus umbellata Fractions on Melanogenesis in α-MSH-Stimulated B16-F10 Melanoma Cells.

When skin is exposed to UV radiation, melanocytes produce melanin. Excessive melanin production leads to skin pigmentation, which causes various cosmetic and health problems. Therefore, the development of safe, natural therapeutics that inhibit the production of melanin is necessary. Elaeagnus umbellata (EU) has long been widely used as a folk medicinal plant because of pharmacological properties that include anti-ulcer, antioxidant, and anti-inflammatory properties. In this study, we investigated the antioxidant activity and melanogenesis inhibitory effects of EU fractions in B16-F10 melanoma cells. EU fractions showed a dose-dependent increase in antioxidant activity in radical scavenging activity. In addition, we evaluated the effect of EU fractions on tyrosinase activity and melanogenesis in α-melanocyte-stimulating hormone-induced B16-F10 melanoma cells. EU was noncytotoxic at 12.5-50 µg/mL. EU fractions effectively inhibited tyrosinase activity and melanogenesis, suppressed the phosphorylation of CREB and ERK involved in the melanogenesis pathway, and down-regulated expression of melanogenesis-related proteins. Interestingly, the anti-melanogenesis effect was most effective at a concentration of 50 µg/mL EU, and the effects of the fractions were superior to those of the extract. Therefore, our study suggests that EU has potential as a safe treatment for excessive pigmentation or as a natural ingredient in cosmetics.

The effect of Aspalathus linearis (Burm.f.) R.Dahlgren and its compounds on tyrosinase and melanogenesis.

Pigmentation, a process controlled by melanogenesis, plays a vital role in protecting the skin against harmful ultraviolet rays. The level of protection is compromised in case of hypopigmentation. This study aimed to evaluate an Aspalathus linearis extract, fractions and phytoconstituents, for their efficacy on melanogenesis stimulation. Fifteen compounds were kinetically assessed against tyrosinase; the rate-limiting enzyme of melanogenesis. Aspalathin and catechin significantly (p value < 0.001) increased the enzymatic rate, showing 50% stimulatory effects at 119.70 ± 2.06 µg/mL and 143.30 ± 2.74 µg/mL, respectively, by acting as subversive substrates. Five compounds inhibited the enzyme's activity, of which four exhibited competitive inhibition. To investigate the molecular interactions between the compounds and the active site, molecular docking was done, using tyrosinase (PBD: 2Y9X) and tyrosinase related protein 1 (PBD: 5M8P). All the compounds docked successfully with acceptable docking scores. Further quantitative structure-activity relationship analysis identified potential functional groups, linked to the specific activity. The crude extract, its fractions, and compounds exhibited low antiproliferative activity with 50% cell viability at concentrations higher than 100 µg/mL. Finally, both aspalathin and catechin exhibited a significant increase (4.5%) in melanin production at 119.82 µg/mL and 76.92 µg/mL, respectively. This is the first report of A. linearis' compounds on skin re-pigmentation.

The effect of isolates from Cassipourea flanaganii (Schinz) alston, a plant used as a skin lightning agent, on melanin production and tyrosinase inhibition.

ETHNOPHARMACOLOGICAL RELEVANCE: The Zulu and Xhosa people of South Africa use the stem bark of Cassipourea flanaganii as a skin-lightning cosmetic. AIM OF THE STUDY: To isolate and identify compounds responsible for the skin lightning properties from the stem bark of Cassipourea flanaganii and to evaluate their cytotoxicity towards skin cells. MATERIALS AND METHODS: Extracts from the stem bark of Cassipourea flanaganii were isolated using chromatographic methods and structures were determined using NMR, IR and MS analysis. The tyrosinase inhibitory activity and the ability to inhibit the production of melanin were determined using human primary epidermal melanocyte cells. Cytoxicity was established using the same melanocytes and a neutral red assay. RESULTS: One previously undescribed compound, ent-atis-16-en-19-al (1) along with the known ent-atis-16-en-19-oic acid (2), ent-atis-16-en-19-ol (3), ent-kaur-16-en-19-oic acid (4), ent-kaur-16-en-19-al (5), ent-manoyl oxide (6), guinesine A (7), guinesine B (8), guinesine C (9), lichenxanthone (10), 2,4-dihydroxy-3,6-dimethyl benzoic acid methyl ester (11), lynoside (12), lupeol (13), ß-amyrin (14), docosyl ferulate (15), stigmasterol, sitosterol and sitosterol-O-glucoside were isolated in this investigation. An impure fraction containing compound 3 was acetylated to obtain 19-acetoxy-ent-atis-16-ene (3a). Compounds 10 and 11 are usually isolated from lichen, hence they are possible contaminants of lichen harvested with the bark. Compounds 1, 3a, 5-14 were not significantly cytotoxic to the primary epidermal melanocyte cells (P > 0.05) when compared to the negative and positive controls (DMSO, 0.1% and hydrogen peroxide, 30 wt% in water). Inhibition of tyrosinase was significantly greater with respect to the negative control (P < 0.001) for compounds 3a, 5-8 and 9-10 at 10 µM and for compounds 5-8 and 9-10 at 100 µM. Compared to hydroquinone (the positive control) at 10 µM, the level of inhibition was comparable or to that of compounds 3a, 5, 6, and 8-10 at 10 µM, with 9 and 10 showing a greater level of inhibition. Inhibition of melanin was both concentration and time dependent for all compounds tested with higher melanin content at 24 h compared to 48 h s and at 10 mM compared to100 mM at both time points; melanin content was significantly lower for hydroquinone at both time points and concentrations. CONCLUSIONS: Compounds 1, 5-14, isolated from Cassipourea flanaganii and the derivative 3a showed low cytotoxicity. All compounds had a clear time and concentration dependent effect on melanin content which did not appear to be dependent on their inhibition of tyrosinase.

Capsaicin Inhibits the Expression of Melanogenic Proteins in Melanocyte via Activation of TRPV1 Channel: Identifying an Inhibitor of Skin Melanogenesis.

Chili pepper belongs to the genus Capsicum of Solanaceae family. Capsaicin is the primary capsaicinoid in placenta and flesh of chili pepper fruit, which has been shown to have various pharmacological functions, including gastric protection, anti-inflammation, and obesity treatment. Here, we revealed that capsaicin as well as chilli extract was able to inhibit synthesis of melanin in melanocytes. In cultured melanocytes, the melanin content was reduced to 54 ± 6.55% and 42 ± 7.41% with p < 0.001 under treatment of 50 µM capsaicin for 24 and 72 h, respectively. In parallel, the protein levels of tyrosinase and tyrosinase-related protein-1 were reduced to 62 ± 8.35% and 48 ± 8.92% with p < 0.001. Such an inhibitory effect of capsaicin was mediated by activation of transient receptor potential vanilloid 1-induced phosphorylation of extracellular signal-regulated kinase. This resulted in a degradation of microphthalmia-associated transcription factor, leading to reduction of melanogenic enzymes and melanin. These results revealed that capsaicin could be an effective inhibitor for skin melanogenesis. Hence, chili pepper, as our daily food, has potential in dermatological application, and capsaicin should be considered as a safe agent in treating hyperpigmentation problems.

The Vascular Component of Melasma: A Systematic Review of Laboratory, Diagnostic, and Therapeutic Evidence.

BACKGROUND: Melasma is a common acquired disorder of hyperpigmentation, classically manifesting as symmetric brown patches on the face. Although the exact pathogenesis is not fully understood, vascular abnormalities have been implicated in melasma. OBJECTIVE: To evaluate the laboratory and clinical evidence regarding the safety and efficacy of antivascular agents for the treatment of melasma. METHODS: A systematic review of PubMed, EMBASE, and Cochrane was conducted on May 13, 2020, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Original research articles investigating the role of vascularity and/or evaluating the use of antivascular therapeutics in melasma were included. Clinical recommendations were based on the American College of Physicians guidelines. RESULTS: A total of 34 original research articles as follows were identified: 4 laboratory studies, 15 diagnostic studies, and 15 therapeutic studies. CONCLUSION: There is promising evidence supporting the use of tranexamic acid and laser/light therapies to treat the vascular component of melasma, and more rigorous clinical trials are needed to validate their efficacy. Clinicians may consider treatment with one or more antivascular therapeutics in patients with melasma. Further research is warranted to characterize the role of cutaneous vascularization in melasma and may provide insights for novel therapies.

Borage Oil Treated with Immobilized Lipase Inhibits Melanogenesis.

In the present study, we demonstrated that borage (Borago officinalis L.) seed oil subjected to immobilized lipase pretreatment are enriched with linoleic acid (LNA, 18:2n-6), γ-linolenic acid (GLA, 18:3n-6), and oleic acid (OLA, 18:1n-9). We further showed that lipase-treated borage oil (LT-BOL) regulates the activity and degradation of tyrosinase, an important enzyme implicated in the synthesis of melanin in murine melanocytes, B16F10. LT-BOL and its free fatty acid components reduced the levels of melanin and tyrosinase in melanocytes with GLA exerting similar or stronger effects compared with LNA and OLA. The brightening efficacy of LT-BOL on melanin metabolism in humans was tested by an 8-week, double-blind, randomized clinical trial, which enrolled 21 Korean female adults (mean age 48.57 ± 3.28). Visual evaluation showed that cream containing 1% LT-BOL significantly decreased (p < 0.05) melasma on the treated skin area after 6 and 8 weeks. The analysis of the skin brightness using Chromameter CR-400 confirmed that the brightness of the treated area was significantly increased (p < 0.01) after 4, 6, and 8 weeks. Together, our results suggest that LT-BOL may be suitable as a natural skin whitening cosmeceutical product.

Roles of Cannabinoids in Melanoma: Evidence from In Vivo Studies.

Melanoma is the fourth most common type of cancer diagnosed in Australians after breast, prostate, and colorectal cancers. While there has been substantial progress in the treatment of cancer in general, malignant melanoma, in particular, is resistant to existing medical therapies requiring an urgent need to develop effective treatments with lesser side effects. Several studies have shown that "cannabinoids", the major compounds of the Cannabis sativaL. plant, can reduce cell proliferation and induce apoptosis in melanoma cells. Despite prohibited use of Cannabis in most parts of the world, in recent years there have been renewed interests in exploiting the beneficial health effects of the Cannabis plant-derived compounds. Therefore, the aim of this study was in the first instance to review the evidence from in vivo studies on the effects of cannabinoids on melanoma. Systematic searches were carried out in PubMed, Embase, Scopus, and ProQuest Central databases for relevant articles published from inception. From a total of 622 potential studies, six in vivo studies assessing the use of cannabinoids for treatment of melanoma were deemed eligible for the final analysis. The findings revealed cannabinoids, individually or combined, reduced tumor growth and promoted apoptosis and autophagy in melanoma cells. Further preclinical and animal studies are required to determine the underlying mechanisms of cannabinoids-mediated inhibition of cancer-signaling pathways. Well-structured, randomized clinical studies on cannabinoid use in melanoma patients would also be required prior to cannabinoids becoming a viable and recognized therapeutic option for melanoma treatment in patients.

Sulforaphane controls the release of paracrine factors by keratinocytes and thus mitigates particulate matter-induced premature skin aging by suppressing melanogenesis and maintaining collagen homeostasis.

BACKGROUND: Skin aging, potentially caused by exposure to particulate matter (PM)2.5, is characterized by wrinkling, abnormal pigmentation, and skin dryness triggered by several keratinocyte-derived paracrine factors. Sulforaphane (4-methylsulfinylbutyl isothiocyanate, SFN), commonly found in cruciferous vegetables, has diverse biological effects on skin tissue. PURPOSE: In the present study, we have investigated whether SFN may alleviate PM2.5-induced premature skin aging. METHODS: We used keratinocyte/melanocyte or keratinocyte/fibroblast coculture models of skin cells and measured the parameters of melanogenesis, collagen homeostasis and inflammation. RESULTS: SFN inhibited the development of reactive oxygen species in keratinocytes exposed to PM2.5. In keratinocyte/melanocyte cocultures, it significantly inhibited the upregulation of melanogenic paracrine mediators (including endothelin-1 and prostaglandin E2) in keratinocytes exposed to PM2.5; the synthesis of melanogenic proteins including microphthalmia-associated transcription factor, tyrosinase-related protein 1, and tyrosinase; and the levels of melanin in melanocytes. SFN treatment of keratinocyte/fibroblast cocultures significantly reduced the PM2.5-induced expression of NF-κB-mediated cytokines including interleukin-1ß, interleukin-6, tumor necrosis factor α, and cyclooxygenase-2. In fibroblasts of the keratinocyte/fibroblast coculture system, the expression levels of phospho-NF-κB, cysteine-rich protein 61, and matrix metalloproteinase-1 were significantly decreased whereas procollagen type I synthesis was significantly increased. CONCLUSION: Collectively, our results suggest that SFN mitigates PM2.5-induced premature skin aging by suppressing melanogenesis and maintaining collagen homeostasis. It acts by regulating the release of paracrine factors from keratinocytes.

Homocysteine induces melanocytes apoptosis via PERK-eIF2α-CHOP pathway in vitiligo.

Vitiligo is a depigmentation disorder that develops as a result of the progressive disappearance of epidermal melanocytes. The elevated level of amino acid metabolite homocysteine (Hcy) has been identified as circulating marker of oxidative stress and known as a risk factor for vitiligo. However, the mechanism underlying Hcy-regulated melanocytic destruction is currently unknown. The present study aims to elucidate the effect of Hcy on melanocytic destruction and its involvement in the pathogenesis of vitiligo. Our results showed that Hcy level was significantly elevated in the serum of progressive vitiligo patients. Notably, Hcy induced cell apoptosis in melanocytes via activating reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress protein kinase RNA-like ER kinase (PERK)-eukaryotic translation initiation factor 2α (eIF2α)-C/EBP homologous protein (CHOP) pathway. More importantly, folic acid, functioning in the transformation of Hcy, could lower the intracellular Hcy level and further reverse the apoptotic effect of Hcy on melanocytes. Additionally, Hcy disrupted melanogenesis whereas folic acid supplementation could reverse the melanogenesis defect induced by Hcy in melanocytes. Taken together, Hcy is highly increased in vitiligo patients at progressive stage, and our in vitro studies revealed that folic acid could protect melanocytes from Hcy-induced apoptosis and melanin synthesis inhibition, indicating folic acid as a potential benefit agent for patients with progressive vitiligo.

RNA helicase DDX21 mediates nucleotide stress responses in neural crest and melanoma cells.

The availability of nucleotides has a direct impact on transcription. The inhibition of dihydroorotate dehydrogenase (DHODH) with leflunomide impacts nucleotide pools by reducing pyrimidine levels. Leflunomide abrogates the effective transcription elongation of genes required for neural crest development and melanoma growth in vivo1. To define the mechanism of action, we undertook an in vivo chemical suppressor screen for restoration of neural crest after leflunomide treatment. Surprisingly, we found that alterations in progesterone and progesterone receptor (Pgr) signalling strongly suppressed leflunomide-mediated neural crest effects in zebrafish. In addition, progesterone bypasses the transcriptional elongation block resulting from Paf complex deficiency, rescuing neural crest defects in ctr9 morphant and paf1(alnz24) mutant embryos. Using proteomics, we found that Pgr binds the RNA helicase protein Ddx21. ddx21-deficient zebrafish show resistance to leflunomide-induced stress. At a molecular level, nucleotide depletion reduced the chromatin occupancy of DDX21 in human A375 melanoma cells. Nucleotide supplementation reversed the gene expression signature and DDX21 occupancy changes prompted by leflunomide. Together, our results show that DDX21 acts as a sensor and mediator of transcription during nucleotide stress.

Design and Development of Spray-Dried Microsystems to Improve Technological and Functional Properties of Bioactive Compounds from Hazelnut Shells.

An extract obtained from hazelnut shells by-products (HSE) has antioxidant and chemopreventive effects on human melanoma and cervical cancer cell lines, inducing apoptosis by caspase-3 activation. A clinical translation is limited by poor water solubility and low bioavailability. Dried plant extracts often show critical characteristics such as sticky/gummy appearance, unpleasant smell, and instability involving practical difficulties in processing for industrial use. A spray drying method has been applied to transform raw HSE in a microparticulate powder. The biopolymeric matrix was based on l-proline as loading carrier, hydroxyethylcellulose in combination with pectin as coating polymers; lecithin and ethanol were used as solubility enhancers. A Hot-Cold-Hot method was selected to prepare the liquid feed. The thus prepared powder showed good technological properties (solid-state, particle dimensions, morphology, and water dissolution rate), stability, and unchanged chemopreventive effects with respect to the unprocessed HSE.

7,8-Dimethoxycoumarin stimulates melanogenesis via MAPKs mediated MITF upregulation.

Background: Melanin in the skin is the defense against the harmful UV radiation, which is considered as one of the major risk factors for skin cancer. The compound 7,8-dimethoxycoumarin (DMC, C11H10O4), a natural coumarin molecule present in several medicinal plants, possesses antioxidant and anti-inflammatory activities. However, the mechanism underlying its effects on melanogenesis in melanocytes is unclear. Therefore, we investigated the effect of DMC on melanogenesis activation in B16F10 melanoma cells. Methods: We examined the cytotoxic range of DMC on B16F10 melanoma cells and increased effects of melanogenesis, and intracellular tyrosinase activity. In addition, regulation mechanisms were assessed by Western blot analysis. Results: The results showed that DMC significantly increased melanin content and tyrosinase activity in the cells without being cytotoxic. Furthermore, DMC stimulated the expression of tyrosinase, TRP-1, TRP-2, and MITF thereby activating melanin production and Akt phosphorylation was increased in the Akt signaling pathway. on the contrary, interfering with the phosphorylation of ERK in the MAPKs pathway. Conclusions: These results suggest that DMC may serve as a candidate for potential melanin-producing activator and anti-gray hair applications.