Melanin Deposition Research Articles

Detection of Snps in the Melanocortin 1-Receptor (MC1R) and Its Association with Shank Color Trait in Hs Chicken

ABSTRACT The melanocortin 1 receptor (MC1R) gene plays a key role in controlling the deposition of melanin. In mammals, the MC1Rgene is regarded as a major candidate gene in the control of melanin formation. In domestic animals, the MC1R gene mainly controls the expression of coat, skin, and plumage color in mammals and birds. In order to breed chickens with dark-green shank faster, we screened the molecular markers for shank color in a HS chicken population by exploring the relationship between polymorphism of the MC1R gene and three different shank colors (light green, dark green and yellow). Two primer pairs for code region of the MC1R gene were designed in the basic of chicken genomic sequence. DNA sequencing was performed to detect the polymorphisms and PCR was used to amplify DNA fragment. Sequences analysis indicated that 7 SNPs were predominant the three HS chicken populations with different shank color, including g.18,287,945C>T, g.18,288,088T>C, g.18,288,150G>A, g.18,288,303A>G, g.18,288,512G>A, g.18,288,513T>C, and g.18,288,520A>C. Association analysis revealed that the dark-green shank population showed moderate polymorphism, whereas the light-green shank population showed low polymorphism among overall 7 SNPs and that SNP6 (g.18,288,513T>C) may be significantly associated with three different shank colors in HS chickens. The haplotype CTGGACA had the largest haplotype frequencies, accounting for 56.22%, and the haplotype combination H1H1 is mainly distributed in the dark-green shank population, and may be used as molecular maker for marker-assisted selection of shank color in HS chickens.

In vivo multiphoton microscopy of melasma.

Melasma is a skin disorder characterized by hyperpigmented patches due to increased melanin production and deposition. In this pilot study, we evaluate the potential of multiphoton microscopy (MPM) to characterize non-invasively the melanin content, location, and distribution in melasma and assess the elastosis severity. We employed a clinical MPM tomograph to image in vivo morphological features in melasma lesions and adjacent normal skin in 12 patients. We imaged dermal melanophages in most dermal melasma lesions and occasionally in epidermal melasma. The melanin volume fraction values measured in epidermal melasma (14%±4%) were significantly higher (p<0.05) than the values measured in perilesional skin (11%±3%). The basal keratinocytes of melasma and perilesions showed different melanin distribution. Elastosis was predominantly more severe in lesions than in perilesions and was associated with changes in melanin distribution of the basal keratinocytes. These results demonstrate that MPM may be a non-invasive imaging tool for characterizing melasma.

Azepine derivative T4FAT, a new copper chelator, inhibits tyrosinase

Melanin plays an important role in the protection of the skin from ultraviolet irradiation. However, excessive melanin deposition leads to hyperpigmentation and freckles, which are recognized as skin problems, and signs of aging. Tyrosinase, a copper-containing protein, is the rate-limiting enzyme in melanin biosynthesis and first catalyzes the hydroxylation of l-tyrosine to 3,4-dihydroxyphenylalanine (DOPA) and the further oxidization to dopaquinone. To assist the proper regulation of melanin production, we screened compounds and found that 5,6,7,8-tetrahydro-4H-furo[3,2-c]azepine-4-thione (T4FAT), a thioamide derivative, inhibited melanogenesis in B16F10 mouse melanoma cells. T4FAT was not toxic to cells and was stable in water; in addition, it inhibited the activity of tyrosinase derived from mushroom and B16F10 cells in a non-competitive manner. T4FAT downregulated tyrosinase protein expression in B16F10 cells without affecting mRNA expression. As copper binding to the tyrosinase protein is required for both enzymatic activity, correct folding, and maturation, we examined the metal-chelating activities of T4FAT. Equimolar amount of T4FAT resulted in almost complete chelation of copper ions. The thioamide group of T4FAT is essential for copper chelation and tyrosinase inhibition, which subsequently resulted in melanogenesis inhibition in B16F10 cells. Although T4FAT has similar in vitro properties to kojic acid, which is also a copper chelator and approved as a component of cosmetic formulations, T4FAT inhibited melanogenesis in B16F10 cells 30 times more efficiently than kojic acid. These results suggested that T4FAT, a novel copper chelator, may be helpful for the development of new cosmetics for skin whitening.

Effect of urea-extracted sericin on melanogenesis: potential applications in post-inflammatory hyperpigmentation

BackgroundHyperpigmentation disorders such as post-inflammatory hyperpigmentation are major concerns not only in light-skinned people but also in Asian populations with darker skin. The anti-tyrosinase and immunomodulatory effects of sericin have been known for decades. However, the therapeutic effects of sericin on hyperpigmentation disorders have not been well documented.MethodsIn this study, we used an in vitro model to study the anti-tyrosinase, tolerogenic, and anti-melanogenic effects of sericin on Staphylococcus aureus peptidoglycan (PEG)-stimulated melanocytes, dendritic cells (DCs), and artificial skin (MelanoDerm™). Enzyme-linked immunosorbent assay, conventional and immunolabeled electron microscopy, and histopathological studies were performed.ResultsThe results revealed that urea-extracted sericin has strong anti-tyrosinase properties as shown by a reduction of tyrosinase activity in melanin pigments both 48 h and 10 days after allergic induction with PEG. Anti-inflammatory cytokines including interleukin (IL)-4, IL-10, and transforming growth factor-β were upregulated upon sericin treatment (10, 20, and 50 µg/mL), whereas production of allergic chemokines, CCL8 and CCL18, by DCs was diminished 48 h after allergic induction with PEG. Moreover, sericin lowered the expression of micropthalmia-associated transcription factor (MITF), a marker of melanogenesis regulation, in melanocytes and keratinocytes, which contributed to the reduction of melanin size and the magnitude of melanin deposition. However, sericin had no effect on melanin transport between melanocytes and keratinocytes, as demonstrated by a high retention of cytoskeletal components.ConclusionIn summary, sericin suppresses melanogenesis by inhibition of tyrosinase activity, reduction of inflammation and allergy, and modulation of MITF function.

Comparative transcriptome profiles of Lindian chicken eyelids identify melanin genes controlling eyelid pigmentation

ABSTRACT1. During the long history of chicken domestication, eyelid colour, like skin colour and shank colour, has been one of the physical traits of Chinese indigenous chickens that influence consumer buying behaviour. In China, the Lindian chicken, which has coloured feathers, is renowned for the appetizing flavour of its meat and eggs, and its eyelid colours vary from deep (black) to light shades (light yellow).2. To investigate genes involved in eyelid colour, the expression profiles of black and light-yellow eyelids of Lindian chickens were analysed with transcriptome sequencing.3. A total of 13 466 genes were detected in the eyelids, among which 14 were differentially expressed. Among these differentially expressed genes (DEGs), three key genes, premelanosome protein (PMEL), dopachrome tautomerase (DCT), and tyrosinase (TYR), encoded proteins that positively regulate melanogenesis and melanin deposition. PMEL, DCT and TYR were expressed much more strongly in the black eyelids than in the light-yellow eyelids. A Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that tyrosine metabolism and melanogenesis genes were significantly enriched among these DEGs (corrected P < 0.05).4. In conclusion, melanin may be one of the main factors involved in Lindian chicken eyelid colour. Furthermore, these results provide a valuable resource for the future study of the physical traits of Lindian chicken.

Stereotactic Radiosurgery for Hemorrhagic Brain Metastases from Malignant Melanoma

Stereotactic radiosurgery is a common treatment modality among patients with brain metastases, particularly from malignant melanoma. In this study, we investigate the difference in local control, toxicity, and survival among patients with hemorrhagic and solid melanoma brain metastases. We collected demographic, treatment, local control, toxicity and survival data for 134 patients with a total of 936 intracranial melanoma metastases who underwent Gamma Knife stereotactic radiosurgery between 1998 and 2015 at the University of Virginia Medical Center. Pre-radiosurgical diagnostic imaging was reviewed for evidence of hemorrhage (melanin containing or clearly hemorrhagic). The population consisted of 92 men and 42 women with a mean age of 61.7 years (range 21.2–84.9) at the time of radiosurgery. Overall survival of patients with brain metastases from malignant melanoma was 42%, 31%, 12% at 12, 24 and 72 months from date of first stereotactic radiosurgery. At 6 months, 43% of the patients with hemorrhagic metastases had local tumor control compared to 83% of solid melanoma metastases (log rank p < 0.001). No significant difference in toxicity was noted between the two groups. Factors that were significantly associated with time to local tumor progression on multivariate analysis include prior WBRT (HR 1.62, p = 0.003), prior chemotherapy (HR 0.69, p = 0.011), margin dose (HR 0.88, p < 0.001) and radiographic features of melanin deposition (HR 3.73, p < 0.001), or clear hemorrhage (HR 2.20, p < 0.001). Our findings demonstrate that hemorrhagic intracranial melanoma metastases are associated with inferior local tumor control when treated with SRS, as compared to solid tumors. These results highlight the importance of early radiosurgery among patients with melanoma brain metastases before hemorrhage occurs. Among patients with hemorrhagic metastases at diagnosis, neurosurgical resection should be considered in appropriate patients.

Primary mediastinal melanotic schwannian tumors: A clinicopathological and immunohistochemical study of 5 cases

Mediastinal neurogenic tumors are unusual and more so is the presence of melanotic neurogenic tumors. We present five cases of mediastinal melanotic neurogenic tumors. The patients are five men between the ages of 34 and 43 years (average: 38.5 years). All patients presented with non-specific symptoms that included back pain and cough. Diagnostic imaging revealed the presence of a posterior mediastinal mass without connection to the spinal canal, and surgical resection was accomplished in all of the patients. Histologically, the five tumors showed a spindle epithelioid cellular proliferation, nuclear atypia, mitotic activity, and melanin deposition. Histochemical stain for Fontana Masson clearly demonstrated the presence of melanin pigment in all the cases, while S-100 protein was only focally positive in tumor cells. Other immunohistochemical stains including SOX-10, MITF, HMB-45, and Melan A were negative. Clinical follow-up showed that two patients died 22 and 30 months after initial diagnosis; one remains alive, 6 months after initial diagnosis; two patients were lost to follow up. Melanotic neurogenic tumors represent a diagnostic challenge for pigmented thoracic tumors and careful analysis of the morphology and immunohistochemistry is required to lead to proper diagnosis.

Redness From Fire: Fevers, Abdominal Pain, and Rash

Erythema ab igne (EAI) is an erythematous dermatosis that arises after repeated heat exposure. We present a case of EAI following chronic use of heating pads for analgesia. A 35-year-old woman with a history of familial Mediterranean fever (FMF), pancreatic exocrine insufficiency, presented to clinic for abdominal pain and fever. She presents to our GI clinic very frequently for FMF flares, which typically present as sharp abdominal pain with fevers, but this visit was unique for a new rash over her abdomen that was superficially nontender and nonpruritic. Over the years, the patient had been controlling her symptoms with colchicine, opioids, and heating pads. The abdominal exam was remarkable for mild tenderness to palpation diffusely, consistent with her previous flares. The overlying skin revealed a diffuse, nonblanching, hyperpigmented red/brown rash, sparing the periumbilical region and not extending into the flanks. Based on her well-known history, a diagnosis of EAI was made, and the patient was encouraged to avoid heating pads to that area. She has since decreased their use, and the discoloration persists but has improved.Erythema ab igne, or “redness from fire,” is a dermatosis that erupts on sites of repeated heat exposure. While historically associated with open fires, recent reports have implicated portable heaters, radiators, and even laptop computers. Two GI-related cases (gastroparesis and Crohn's disease), linked EAI with hot water bottles. The rash starts as a transient, reticulate, macular erythema, but with chronic heat exposure, becomes more livid and hyperpigmented. The heat is believed to cause superficial vasculature damage and dilation leading to erythema, and eventually, a more permanent hemosiderin and melanin deposition, which are presennt on biopsy and correlates to the darker hue. Usually, EAI resolves with avoidance of the causative heat source, although long-standing hyperpigmentation may persist for years. Reported treatments include topical 5-fluorouracil, bioflavonoids, trichloroacetic acid, and imiquimod. Biopsy is indicated if malignancy is suspected, as EAI has been rarely implicated in transformation into cutaneous squamous cell and Merkel cell carcinoma. Our case is particularly relevant to gastroenterologists since what can be an initially alarming abdominal rash that turns out to be a benign, self-resolving dermatosis, may at times end up serving as a clue for an underlying, more-serious GI issue.1852 Figure 1 No Caption available.

Semiconducting Synthetic Melanin-Based Organic/Inorganic Hybrid Photoanodes for Solar Water Oxidation.

We report the development of semiconducting melanin-based organic/inorganic hybrid photoanodes for solar water oxidation. Synthetic melanin thin-film incorporating polyoxometalate (POM) water oxidation catalysts (WOCs) are readily deposited on the surface of various n-type inorganic semiconductors (e.g., Fe2 O3 , BiVO4 , and TiO2 ) by electropolymerization. The deposition of melanin and POM hybrid (MP) thin-film results in the remarkably improved performance of an underlying semiconductor photoanode for solar water oxidation with a significantly increased photocurrent density and decreased onset potential for water oxidation through the formation of a melanin-based p-n heterojunction structure. We believe that this study can provide insights into the design and fabrication of various melanin-based optoelectronic devices by utilizing its unique physicochemical properties.

Oral Postinflammatory Pigmentation: Clinicopathologic Features of Nine Cases

Oral postinflammatory pigmentation (OPP) is a pigmentary change of the oral mucosa caused by high melanin production, often associated with chronic inflammatory disorders. Several conditions could lead to OPP, including oral lichen planus (OLP), oral lichenoid lesion (OLL), pemphigus, and pemphigoid. Here, we present 9 OPP cases. The main clinical characteristic in all the cases was oral black to brown pigmentation, localized or diffuse, microscopically exhibiting melanin deposition in the lamina propria. Five were men and 4 women (mean age 52 years). Five cases showed occurrence on the buccal mucosa and the other cases on the lower lip, hard palate, mouth floor, and labial commissure. Four cases were associated with leukoplakia, 2 with OLL, and 1 case each with OLP, actinic cheilitis, and fibrous hyperplasia. More studies involving large series of OPP cases should be conducted for a better understanding of their etiopathogenic mechanisms and clinicopathologic features.

The role of systemic treatments for skin lightening.

Pigmentation of the skin occurs as a result of increased melanin production or deposition due to various reasons including age, hormonal imbalances, endocrine disease, inflammation, and/or exposure to damaging radiation, resulting in dermatologic conditions such as lentigines, melasma, or postinflammatory hyperpigmentation. Although numerous topical therapies exist for skin lightening, they are limited by efficacy and pigmentation recurrence after treatment cessation. New research into systemic therapies for hyperpigmentation has been promising. To summarize the current literature for systemic skin lightening therapies. A review of the literature surrounding systemic skin lightening therapies was completed using PubMed (US National Library of Medicine). Multiple systemic therapies for skin lightening exist including oral carotenoids, glutathione, melatonin, Polypodium leucotomos hydrophilic extract, procyanidin, and tranexamic acid. Preliminary data for the treatment of hyperpigmentation are promising, and currently, these oral treatments appear safe. It is not suggested to use intravenous glutathione for skin lightening due to the increased risk of adverse events. With the patient population seeking effective systemic treatments for skin pigmentation, it is important for dermatologists to understand the properties, the efficacy, and the adverse events profile of each compound, thus ensuring proper use by patients, and that patients are appropriately counseled regarding treatment expectation and safety.

CVDentus bur for epithelial abrasion in the treatment of melanin pigmentation: case report

Introduction: The gingival melanin hyperpigmentation (GMH) is resulted from an abnormal deposition of melanin, but it is not a pathology. However, GMH is an esthetic problem for some people. Some alternatives of treatment for this situation exist. The epithelial abrasion has been an interesting alternative because it has a satisfactory esthetic outcome, is a fast procedure, of easy execution, and low cost. Recently, tips adapted in ultrasound (CVDentus) can bean alternative approach. Objective: To report a clinical case of GMH treated by the technique of the epithelial abrasion with association of instrument adapted in ultrasound. Case report: Patient aged 28 years, melanoderm, sought treatment due to esthetic dissatisfaction because of intense dark color in the maxillary gingiva. The GMH removal was proposed through the technique of the epithelialabrasion CVD bur. Conclusion: The technique of epithelial abrasion using CVD bur was effective in removing GMH at one-year follow-up showing to be easy and safe technique.

Stereotactic radiosurgery for brain metastases from malignant melanoma and the impact of hemorrhagic metastases.

Stereotactic radiosurgery (SRS) is a common treatment modality among patients with brain metastases, particularly from malignant melanoma. Our objective was to investigate the difference in local control, toxicity, and survival among patients with hemorrhagic and solid melanoma brain metastases. We collected demographic, treatment, local control, toxicity, and survival for 134 patients with a total of 936 intracranial melanoma metastases who underwent SRS between 1998 and 2015. Pre-radiosurgical diagnostic imaging was reviewed for evidence of hemorrhage (melanin-containing or clearly hemorrhagic). The cohort consisted of 92 men and 42 women with a mea age of 61.7years (range 21.2-84.9) at the time of radiosurgery. Overall survival of patients with brain metastases from malignant melanoma was 42, 31, 12% at 12, 24, and 72months from date of first SRS. At 6 months, 43% of the patients with hemorrhagic metastases had local tumor control compared to 83% of solid melanoma metastases (p < 0.001). No significant difference in toxicity was noted between the two groups. Factors that were significantly associated with time to local tumor progression on multivariate analysis include prior WBRT (HR 1.62, p = 0.003), prior chemotherapy (HR 0.69, p = 0.011), margin dose (HR 0.88, p < 0.001) and radiographic features of melanin deposition (HR 3.73, p < 0.001), or clear hemorrhage (HR 2.20, p < 0.001). Our findings demonstrate that hemorrhagic intracranial melanoma metastases are associated with inferior local tumor control when treated with SRS, as compared to solid tumors. These results highlight the importance of early radiosurgery among patients with melanoma brain metastases before hemorrhage occurs.

&lt;i&gt;Francisella halioticida&lt;/i&gt;, Identified as the Most Probable Cause of Adductor Muscle Lesions in Yesso scallops &lt;i&gt;Patinopecten yessoensis&lt;/i&gt; Cultured in Southern Hokkaido, Japan

The occurrence of orange/pinkish colored lesions in the adductor muscle of Yesso scallops Patinopecten yessoensis has been known for many years in Japan; however, determination of the causative agent has not been adequately investigated. ​Histological examination of affected scallops in southern Hokkaido typically revealed intense host responses: hemocyte infiltration, an abundance of necrotic hemocytes, lysis of muscle fibers and in some instances melanin deposits when the lesions occurred adjacent to the shell. ​Microbiota analysis showed that Francisella halioticida was dominant in the lesions, and in situ hybridization using F. halioticida specific probes also confirmed the presence of this bacterium within the lesions. ​A F. halioticida specific PCR assay detected this bacterium in the majority of scallop lesions tested. ​Subsequently, three bacterial isolates were obtained from scallop lesions on modified Eugon agar supplemented with antibiotics, and these bacterial isolates were found to be F. halioticida by 16S rRNA and rpoB gene sequences. ​These results suggest that infection with F. halioticida is the most likely cause of the adductor muscle lesions observed in Yesso scallops. ​Field surveys conducted in 2017 of scallops cultured in southern Hokkaido showed that the presence of adductor muscle lesions putatively caused by F. halioticida was significantly related to mortalities and poor growth of scallops.

Study on herbal textual evolution and flavonoids and their pharmacological of Spatholobi Caulis

Spatholobi Caulis, the vine stem of Spatholobus suberectus and widely used in China and Southeast Asian nations, has the effects on nourishing the blood and promoting blood flow, regulating menstruation and relieving pain, and invigorating the nerves. Through consulting the herbal textual and local chronicles, we summarized the original textual research and medicinal evolution on Spatholobi Caulis to analyze the changes of varieties in different historical periods. Further, the major active ingredient in Spatholobi Caulis was discussed. According to the literature to date, 60 flavonoids compounds have been isolated and could be divided into isoflavones, dihydroflavones, flavanols, dihydroflavonols, procyaninides, chalcones, pterocarpans, isoflavanols, isoflavanones and aurone according to their molecular structures. These indicative ingredients in Spatholobi Caulis showed pharmacological activities on regulation of the blood system, anti-tumor, anti-oxidation, anti-virus, anti-bacteria and inhibition of melanin deposition. This review will provide reference and basis for the sustainable use of resources and industry development on Spatholobi Caulis.

Basal cell carcinoma induced by therapeutic radiation for tinea capitis-clinicopathological study.

An increased prevalence of aggressive histological subtypes, such as micronodular and morpheaform, has been seen, irrespective of the clinical course, in basal cell carcinoma (BCC) following irradiation for tinea capitis. The aim of this study was to assess the histopathological features of BCCs among patients irradiated for tinea capitis and correlate them with the clinical course. The medical records and BCC biopsy specimens of individuals who were previously irradiated for tinea capitis were reviewed. Demographic data and clinical characteristics were retrieved. Biopsy specimens were evaluated for histological subtype classification and additional histopathological features. A telephone survey was conducted to assess the clinical behaviour of the tumours. Thirty-one patients (17 male; 14 female) were included. The average age at time of first biopsy was 56 years. The total number of lesions was 185, with 80% of subjects showing multiple lesions. The nodular subtype was the most prevalent, followed by superficial, micronodular and mixed tumours. One-third of the BCCs could be classified as aggressive histologically. Stromal fibroplasia and melanin deposits were common. There was no mortality related to BCC. None of the 17 patients who completed the survey had evidence of local invasiveness or metastases. BCCs following radiation therapy for tinea capitis show unique histological characteristics related to aggressive behaviour. These aggressive features did not reflect the clinical behaviour in the current cohort.

Primary Cutaneous Adenoid Cystic Carcinoma Connecting to the Epidermis

Primary Cutaneous Adenoid Cystic Carcinoma Connecting to the Epidermis

Pharmacokinetic and Pharmacodynamics of Self-Assembled Cubic Liquid Crystalline Nanoparticle Gel After Transdermal Administration.

BackgroundThe aim of this study was to assess the pharmacokinetics after transdermal administration by a novel skin microdialysis technology in rats. The guinea pig model was established by investigating the pharmacodynamics.Material/MethodsThree different agents were given after hair removal, and the samples were extracted by microdialysis and detected by HPLC. Subcutaneous/plasma concentration-time curves of the 3 different agents were analyzed and the pharmacokinetic parameters were calculated. The SS-04B UV light therapy instrument was used in the modeling. Changes in melanin index and histopathology were observed with HE staining.ResultsThe increment and decrement results showed that the concentration had no significant effect on drug recovery both in vivo and in vitro. After the paeonol cubic liquid crystalline nanoparticles gel (PAE-LCNPs) was administered, the maximum peak time (tmax) of paeonol skin concentration appeared at 2.42±0.20 h, the maximum skin concentration Cmax was (926±105) ng/ml, and the area under the curve AUC0–8 was (8056±954) ng/h/ml. The tmax was shortened much more than in the other groups, and the performance of PAE-LCNPs targeting was good. Pharmacodynamic results showed that PAE-LCNPs can reduce melanocytes and reduce the melanin index, proving its utility in the treatment of melanin deposition.ConclusionsThe skin microdialysis study indicated PAE-LCNPs have good transdermal permeability and efficacy. Pharmacological experiments based on the study found that the topical pigmentation model of guinea pigs showed a better therapeutic effect.

Mechanisms of developmental toxicity in zebrafish embryos (Danio rerio) induced by boscalid

Boscalid has been widely used for controlling various plant diseases. It is one of the most frequently detected pesticides in main coastal estuaries in California, with concentrations as high as 36μg/L, but its ecotoxicology information is scarce. To assess the aquatic risk of boscalid, acute toxicity and sub-lethal developmental toxicity toward zebrafish embryos were determined in the present study. In the acute toxicity test, a series of toxic symptoms of embryos were observed, including abnormal spontaneous movement, slow heartbeat, yolk sac oedema, pericardial oedema, spine deformation and hatching inhibition, and 96-h-LC50 (50% lethal concentration) of boscalid toward zebrafish embryos was 2.65 (2.506–2.848)mg/L. From the results of the sub-lethal developmental toxicity test, boscalid was confirmed to have a great impact on development mechanisms of zebrafish embryos. Cell apoptosis in embryos was induced by boscalid with upregulation of genes in the cell apoptosis and an increase of capspase-3 and caspase-9 activity in the present study. Lipid metabolism was affected in embryos due to changes in gene expression and the contents of total triacylglyceride and cholesterol. Melanin synthesis and deposition was caused in embryos due to alterations in related gene expression. Overall, changes in cell apoptosis, lipid metabolism and melanin synthesis and deposition might be responsible for developmental toxicity of boscalid to zebrafish embryos.

Tetrahydrofuran lignans: Melanogenesis inhibitors from Premna integrifolia wood collected in Myanmar

Two new tetrahydrofuran lignans, taungtangyiols A (1) and B (2), and eight known furofuran lignans (3−10), were isolated from the chloroform extract of Premna integrifolia wood collected in Myanmar. Their structures were elucidated by extensive spectroscopic techniques. The X-ray crystal structure of 1 clearly indicated its relative configuration. Taungtangyiols A (1) and B (2) inhibited the deposition of melanin in B16F10 mouse melanoma cells, with IC50 values of 50.7 and 40.9 μM, respectively, without notable cytotoxicity. An SAR study demonstrated that the furofuran and dioxymethylene moieties of the lignans play a vital role in inhibiting melanogenesis.