Eumelanin and pheomelanin in tissue samples can be specifically measured as the markers pyrrole-2,3,5-tricarboxylic acid (PTCA) 4-amino-3-hydroxyphenylalanine after acidic permanganate oxidation hydroiodic hydrolysis, respectively. Those degradation methods, although widely applied, are not easily performed most laboratories. To overcome this difficulty, we developed alkaline H(2)O(2) 1 M K(2)CO(3) that produces, addition to eumelanin marker PTCA, thiazole-2,4,5-tricarboxylic (TTCA)...

Tyrosinase is the rate-limiting enzyme of melanin production and, accordingly, most prominent target for inhibiting hyperpigmentation. Numerous tyrosinase inhibitors have been identified, but those lack clinical efficacy because they were identified using mushroom as target. Therefore, we used recombinant human to screen a library 50,000 compounds and compared active screening hits with well-known whitening ingredients. Hydroquinone its derivative arbutin only weakly inhibited half-maximal...

Abstract The influence of the cytokine interleukin‐12 (IL‐12) on humoral immune responses was studied in vivo . CBA/J mice immunized with protein antigens (keyhole limpet hemocyanin, phospholipase A 2 ) adsorbed to aluminum hydroxide (Alum) develop a Th2‐like response characterized by production large amounts IgG1 as well some IgE but little IgG2a, IgG2b and IgG3 antibodies. IL‐12 is that promotes development activation Th1 cells. cells are involved induction cellular immunity, which low or...

Abstract Background Hyperpigmentary disorders like melasma, actinic and senile lentigines are a major cosmetic concern. Therefore, many topical products available, containing various active ingredients aiming to reduce melanin production distribution. The most prominent target for inhibitors of hyperpigmentation is tyrosinase, the key regulator production. Many tyrosinase described in literature; however, them lack clinical efficacy. Methods We were interested evaluating inhibition skin...

The relationship between human skin pigmentation and protection from ultraviolet (UV) radiation is an important element underlying differences in carcinogenesis rates. association UV damage the risk of cancer clear, yet a strategic balance exposure to needs be met. Dark protected UV-induced DNA significantly more than light owing constitutively higher pigmentation, but as unresolved question what photoprotective benefit, if any, afforded by facultative (i.e. tan induced exposure). To address...

Melasma is a pigmentary disorder characterized by hyperpigmented patchy skin in sun-exposed areas, especially the face. Treatment of melasma can be challenging because long-term therapy required, reoccurrence common, and existing therapies are insufficient unsatisfactory. To investigate new treatment options, we performed an exploratory double-blinded, randomized split-face study to assess efficacy tyrosinase inhibitor Thiamidol compared hydroquinone women with mild moderate melasma. After...

Atrophy is a distressing side effect of potent corticosteroids. After open application high potency steroid, we monitored atrophogenicity by variety non-invasive methods.Volar forearms were treated twice daily for 3 or 4 weeks, with clobetasol propionate cream (Temovate). The following methods used: 1) confocal microscopy, 2) transepidermal water loss (TEWL), 3) dimethyl sulfoxide whealing, 4) sodium hydroxide erosions, 5) analysis stratum corneum lipids, and 6) B-scan ultrasound.Confocal...

Interactions between melanocytes and neighboring cells in the skin are important regulating color humans. We recently demonstrated that less pigmented thicker on palms soles is regulated by underlying fibroblasts those areas, specifically via a secreted factor (DKK1) modulates Wnt signaling. In this study, we tested hypothesis dermal regulate constitutive of individuals ranging from very light to dark. used microarray analysis compare gene expression patterns derived lighter types compared...

Eumelanin is photoprotective while pheomelanin phototoxic to pigmented tissues. Ultraviolet A (UVA)-induced tanning seems result from the photooxidation of pre-existing melanin and contributes no photoprotection. However, data available for biodegradation remain limited. In this study, we first examined photodegradation eumelanin in human black hairs found that ratio Free (formed by peroxidation situ) Total (after hydrogen peroxide oxidation) pyrrole-2,3,5-tricarboxylic acid (PTCA) increases...

The molecular and cellular mechanisms controlling Ab isotype selection following encounter of a given Ag are still unclear, although the regulatory role cytokines is established. In present study we explored possibility that nonimmunologic interaction an allergen with cells innate immune system might result in release mediators promote IgE adaptive responses. Using bee venom phospholipase A2 (PLA2) mutant variant lacking enzymatic function, show PLA2, but not its catalytically inactive...

Analyzing mechanisms and key players in peripheral nociception nonneuronal skin cells are getting more into focus. Herein we investigated the functional expression of TRPV1 TRPA1 human keratinocytes fibroblasts assessed proinflammatory lipid mediator release upon their stimulation as well sensory effects after topical application, combining vitro vivo approaches. In vitro, channels on was confirmed via immunofluorescence, qualitative real time (RT) polymerase chain reaction, cellular Ca(2+)...

Abstract Age spots, also called solar lentigines and lentigo senilis, are light brown to black pigmented lesions of various sizes that typically develop in chronically sun‐exposed skin. It is well known age spots strongly related chronic sun exposure associated with photodamage an increased risk for skin cancer; however, the mechanisms underlying their development remain poorly understood. We used immunohistochemical analysis microarray investigate processes involved formation, focusing on...

Summary Although photodegradation of the retinal pigment epithelium ( RPE ) melanin may contribute to etiology age‐related macular degeneration, molecular mechanisms this phenomenon and structural changes modified remain unknown. Recently, we found that ratio pyrrole‐2,3,4,5‐tetracarboxylic acid PT e CA pyrrole‐2,3,5‐tricarboxylic PTCA is a marker for heat‐induced cross‐linking eumelanin. In study, examined UVA ‐induced in synthetic eumelanins confirm usefulness / as an indicator...

Tyrosinase inhibitors are of great clinical interest as agents for the treatment hyperpigmentary disorders; however, most compounds described in literature lack efficiency due to insufficient inhibitory activity against human tyrosinase (hTyr). Recently, we reported that thiazolyl resorcinols (4-resorcinylthiazol-2-amines and -amides) both selective efficacious hTyr vitro vivo. Here, measured dose-activity profiles a large number analogous better understand molecular basis their interaction...

Abstract Background Solar radiation causes skin damage through the generation of reactive oxygen species (ROS). While UV filters effectively reduce UV‐induced ROS, they cannot prevent VIS‐induced (400‐760 nm) oxidative stress. Therefore, potent antioxidants are needed as additives to sunscreen products. Methods We investigated ROS formation and photoprotective effects Nrf2 inducer Licochalcone A (LicA). Results Visible spectrum 400‐500 nm dose‐dependently induced in cultured human...

Post-inflammatory hyperpigmentation (PIH) is a major cosmetic concern especially in individuals with darker skin complexion. Unfortunately, treatment anti-inflammatory ingredients alone does not prevent the development of hyperpigmented spots. Recently, isobutylamido-thiazolyl-resorcinol (Thiamidol) was described as very potent inhibitor human tyrosinase. The objective this research to investigate potential compound PIH induced by epidermal wounding (suction blister) and related acne.Suction...

Objective: Post-inflammatory hyperpigmentation (PIH) is a major cosmetic concern especially in individuals with darker skin complexion. Unfortunately, treatment anti-inflammatory ingredients alone does not prevent the development of hyperpigmented spots. Recently, Thiamidol (isobutylamido thiazolyl resorcinol) was described as very potent inhibitor human tyrosinase. The objective this research to investigate potential Thiamidol-based formulations PIH induced by acne-induced epidermal...

Thiamidol (isobutylamido thiazolyl resorcinol): A Highly Specific Human Tyrosinase Inhibitor for the Treatment of Hyperpigmentation Tobias Mann1, Wolfram Gerwat1, Jan Batzer1, Kerstin Eggers1, Cathrin Scherner1, Horst Wenck1, Franz Stab1, Vincent J. Hearing2, Klaus-Heinrich Rohm3, Ludger Kolbe1 1Front End Innovation, Beiersdorf AG, Hamburg, Germany; 2DASS Manuscript, Haymarket, Virginia, USA; 3Institute Physiological Chemistry, Philipps University, Marburg, Germany is rate-limiting enzyme...

Clinical Efficacy of the Human Tyrosinase Inhibitor Thiamidol (isobutylamido thiazolyl resorcinol) in Melasma Dennis Roggenkamp1, Adel Sammain1, Manuela Fürstenau2, Martina Kausch2, Thierry Passeron3,4, Ludger Kolbe2 1International Medical Management, Beiersdorf AG, Hamburg, Germany, 2Research & Development, 3Centre Méditerranéen de Médecine Moléculaire – C3M, University Côte d’Azur, INSERM U1065, Nice, France, 4Department Dermatology, CHU France was most potent inhibitor human...

Psychological stress has been shown to impact skin and DNA methylome, but the mechanisms are poorly understood. Here, we collected multi-omics data from 60 stressed relaxed individuals test hypothesis that psychological may via epigenetic modification downstream altered gene expression. Each volunteer completed a series of questionnaires assessments measure their levels condition. Suction blister samples were for analyze cytokines, transcriptome. The dataset generated allowed identification...

The retrochalcone licochalcone A (LicA) has previously been shown to possess antimicrobial and anti-inflammatory properties. In this study, we focused on pathways responsible for the antioxidative properties of LicA. vitro, LicA protected from oxidative stress mediated by reactive oxygen species (ROS) activating expression cytoprotective phase II enzymes. induced nuclear translocation NF-E2-related factor 2 (Nrf2) in primary human fibroblasts elevated enzymes heme oxygenase 1...