Skin Melanin Research Articles

Regulation of eumelanogenesis-related genes by ethanol extract of Melaleuca Leucadendron leaves.

Eumelanin, a type of skin melanin pigment, possesses the ability to absorb a wide range of wavelengths, providing protection to the skin from ultraviolet radiation. However, excessive production of eumelanin may result in hyperpigmentation. Consequently, the development of skin-brightening products that suppress eumelanin synthesis to achieve a lighter and more even skin tone is necessary. The present study investigated the potential application of Melaleuca leucadendron as a natural skin-brightening agent. We investigated the effects of the ethanol leaf extract of M. Leucadendron on α-melanocyte-stimulating hormone-induced melanogenesis in B16F10 cells and identified the key factors involved in melanogenesis. This leaf extract significantly inhibited melanin production by downregulating the expression of microphthalmia-associated transcription factor, tyrosinase, tyrosinase-related protein 1, and dopachrome tautomerase without causing cytotoxicity. Furthermore, it substantially reduced melanin content in a 3D skin model. These results suggest that the extract of M. Leucadendron is a promising, safe, and effective skin-brightening agent.

Extraction and Characteristics of Melanin from Black Soldier Fly (BSF) Pupal Skin as Biopolymer Raw Material

The generation of organic waste has increased globally in recent years. One way to degrade waste more quickly and carry out the bioconversion process of organic waste is to use insects. This BSF has attracted researchers to cultivate and utilize this biomass to extract biochemicals. However, in this research, pupal skin melanin (PSM) from BSF waste is used to obtain melanin. Melanin is a group of blackish-brown pigments with strong physical, chemical, and antimicrobial properties. These properties can be used as an alternative biopolymer material for various environmental sustainability purposes. The melanin extraction method consists of three main steps, namely demineralization, deproteination, and deacetylation, which will be compared with the results of melanin purification from Sepia officinalis melanin (SOM). Characteristics using FTIR, SEM, and EDS to determine the comparison of the quality of melanin obtained from the extraction of pupal skin with commercial melanin from Sepia officinalis. The research results obtained from FTIR analysis show that there are distinctive peaks that correspond to the structure of melanin, including hydroxyl groups (-OH), amine groups (-NH), carboxyl groups (-COOH), and aromatic groups. For SEM analysis, the morphology of PSM and SOM shows differences in surface condition. The melanin resulting from Sepia officinalis is not homogeneous and contains many lumps or aggregates. Whereas the surface of melanin from pupal skin is more homogeneous or looks smoother, but there are still small aggregates on the surface. Furthermore, from the EDS analysis, the total pure concentration was 99.33% for SOM and 69.78% for PSM.

Hybrid deep learning-based skin cancer classification with RPO-SegNet for skin lesion segmentation

ABSTRACT Skin melanin lesions are typically identified as tiny patches on the skin, which are impacted by melanocyte cell overgrowth. The number of people with skin cancer is increasing worldwide. Accurate and timely skin cancer identification is critical to reduce the mortality rates. An incorrect diagnosis can be fatal to the patient. To tackle these issues, this article proposes the Recurrent Prototypical Object Segmentation Network (RPO-SegNet) for the segmentation of skin lesions and a hybrid Deep Learning (DL) – based skin cancer classification. The RPO-SegNet is formed by integrating the Recurrent Prototypical Networks (RP-Net), and Object Segmentation Networks (O-SegNet). At first, the input image is taken from a database and forwarded to image pre-processing. Then, the segmentation of skin lesions is accomplished using the proposed RPO-SegNet. After the segmentation, feature extraction is accomplished. Finally, skin cancer classification and detection are accomplished by employing the Fuzzy-based Shepard Convolutional Maxout Network (FSCMN) by combining the Deep Maxout Network (DMN), and Shepard Convolutional Neural Network (ShCNN). The established RPO-SegNet+FSCMN attained improved accuracy, True Negative Rate (TNR), True Positive Rate (TPR), dice coefficient, Jaccard coefficient, and segmentation analysis of 91.985%, 92.735%, 93.485%, 90.902%, 90.164%, and 91.734%.

Developing translucent emulsions using sustainable NADES-based extracts

In this work, we explored natural deep eutectic solvents (NADES) for developing translucent NADES-in-oil emulsions (TEs) for cosmetic applications. NADES, composed of lactic acid and glycerol (1:1 and 1:4 ratios), were selected for their natural origin, non-toxicity, and compatibility with living organisms. These green solvents facilitated the extraction of bioactive compounds from Lavandula angustifolia, Corymbia citriodora, Thymus vulgaris, Quercus suber, Allium sativum, and Origanum vulgare. The resulting NADES-extracts were characterized using LC-MS for compound identification and incorporated into TEs formulations. The content of phenolics, flavonoids, chelating power, and the antioxidant activity were assessed for both NADES-extracts an TEs. The produced TEs (50 wt% egg L-α-phosphatidylcholine (EPC), 20 wt% ethanol, 20 wt% olive oil, and 10 wt% NADES/NADES-extracts) effectively hindered the activity of enzymes responsible for skin melanin regulation and aging, namely tyrosinase (IC50 ≈ 0.18 mg/mL for eucalyptus) and elastase (IC50 ≈ 0.23 mg/mL for thyme). Gram-negative bacteria, particularly K. pneumoniae, were found to be more susceptible to NADES-extracts and TE-extracts, resulting in larger zones of inhibition. The study reported no toxic effects in the larval model, with a noticeable decrease (2-fold) in melanization in G. mellonella larvae after TE application. Cytotoxicity results indicated that TEs could be tolerated in skin cells at concentrations up to 5 %. Transdermal testing showed TEs permeation into the skin of 1–5 %, suggesting their use for cosmetic purposes without significant cellular damage. This study highlights the potential of NADES combined with natural extracts as sustainable, non-toxic ingredients in cosmetic formulations, paving the way for innovative skin regeneration products.

Integrated deep learning approach for generating cross-polarized images and analyzing skin melanin and hemoglobin distributions.

Cross-polarized images are beneficial for skin pigment analysis due to the enhanced visualization of melanin and hemoglobin regions. However, the required imaging equipment can be bulky and optically complex. Additionally, preparing ground truths for training pigment analysis models is labor-intensive. This study aims to introduce an integrated approach for generating cross-polarized images and creating skin melanin and hemoglobin maps without the need for ground truth preparation for pigment distributions. We propose a two-component approach: a cross-polarized image generation module and a skin analysis module. Three generative adversarial networks (CycleGAN, pix2pix, and pix2pixHD) are compared for creating cross-polarized images. The regression analysis network for skin analysis is trained with theoretically reconstructed ground truths based on the optical properties of pigments. The methodology is evaluated using the VISIA VAESTRO clinical system. The cross-polarized image generation module achieved a peak signal-to-noise ratio of 35.514dB. The skin analysis module demonstrated correlation coefficients of 0.942 for hemoglobin and 0.922 for melanin. The integrated approach yielded correlation coefficients of 0.923 for hemoglobin and 0.897 for melanin, respectively. The proposed approach achieved a reasonable correlation with the professional system using actually captured images, offering a promising alternative to existing professional equipment without the need for additional optical instruments or extensive ground truth preparation.

Wnt5a negatively regulates melanogenesis in primary Arctic fox epidermal melanocytes

Melanocytes, which are mainly found in the epidermis, are responsible for the melanin of skin and hair, and thereby contribute to the appearance of skin and provide protection from damage by ultraviolet radiation. Our previous study revealed that the Wnt5a, one of the many genes that affect melanin production, might be involved in the coat color seasonal change of the Arctic fox by influencing skin melanogenesis. Although the role of Wnt5a in melanocyte lines and melanoma cells has been extensively studied, its role in primary epidermal melanocytes has not been explored. This study aimed to investigate the role and mechanism of the Wnt5a in influencing melanogenesis in Arctic fox primary epidermal melanocytes. We constructed the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) knockout plasmid targeting exons of the Wnt5a and transfected it into primary epidermal melanocytes. The results of the amplification knockout region assay, RT-qPCR assay, and western blot assay showed the success of Wnt5a knockout. RT-qPCR assay and melanin content assay showed that melanin production in melanocytes was significantly increased after Wnt5a knockout, and melanin-related key genes, such as microphthalmia-associated transcription factor, tyrosinase and tyrosinase-related protein 1, were significantly elevated. In addition, we also found that the expression of the β-catenin gene of the Wnt canonical pathway was significantly elevated after Wnt5a knockout. In conclusion, our results indicate that the Wnt5a plays a negative regulatory role in melanogenesis in primary epidermal melanocytes, and is presumably involved in antagonizing or inhibiting canonical Wnt signaling.

Modulation of Melanocyte in Melasma Patients After Picosecond Laser Treatment.

Melasma is a therapeutically challenging hyperpigmented skin condition. Currently, there is a lack of invivo observation regarding changes in melanin and dendritic melanocytes after laser treatment. To investigate alterations in melanin and melanocytes in melasma before and after laser treatment using optical coherence tomography (OCT). Eight female melasma patients were enrolled in Taiwan. Based on the baseline OCT scans, the patients were categorized into either epidermal-type or mixed-type melasma and were assigned different treatment protocols accordingly. Sequential OCT images were collected from melasma lesions and normal skin at baseline, Week 4 and Week 8. After 8 weeks of laser treatment, the mean Melasma Area Severity Index (MASI) score improved from 10.92 to 6.30. Results from OCT showed no significant changes in the normalized density, area, or intensity of melanin in both lesional and normal skin. At baseline, the mean length of dendritic melanocytes in the affected skin was 15% longer than those in normal skin; at Week 8, the mean length of lesional dendritic melanocytes became the same as those in normal skin. Additionally, the mean width of dendritic melanocytes decreased from being 4% wider to only 2% wider than those in normal skin. After 8 weeks of treatment, an improvement of MASI score was noted, mainly attributable to a reduction in lesional area. OCT showed no notable change regarding melanin, but a decrease in length and width of dendritic melanocytes was noted in the lesional skin of melasma patients.

Dynamic changes in the skin transcriptome for the melanin pigmentation in embryonic chickens

Dermal hyperpigmentation stands out among the various skin pigmentation phenotypes in chickens, where most other pigmentation variants affect feather color and patterning predominantly. Despite numerous black chicken breeds worldwide, only a select few exhibit comprehensive black pigmentation, which encompasses the skin, meat, flesh, and bones. The process of skin melanin pigmentation is intricate and develops successively. Historically, research has concentrated primarily on specific developmental points or stages, but fewer studies have examined the entire transcriptome across the timeline of the development of the embryo integument. In our investigation, we undertook the sequencing of chicken embryo skin samples from d 4 to d 13 of incubation. Our results showed that melanoblasts continued to migrate from E4 to the epidermis until E12. Beginning with E6, melanin was synthesized and transferred to epidermal cells and feather follicles in large quantities, and genes such as DCT, TYR, TYRP1, and MITF played a key role in this process, which is significantly different from that of white-skinned chickens. There were 854 differentially expressed genes between E7 and E8. At this stage, melanocytes formed dendritic forms and transferred melanin to keratinocytes, while the dorsal skin became visibly dark. In addition, CDH3, which is a core factor involved in a variety of biological processes, may have an important impact on skin melanin pigmentation. Collectively, our findings unveiled a phased relationship between the canonical pathway and the noncanonical pathway from E4 to E13. These analyses illuminated the gene regulatory mechanism and provided foundational data that pertained to pigmentation in chickens.

Hydrolyzed conchiolin protein inhibits melanogenesis through PKA/CREB and MEK/ERK signalling pathways.

Hydrolyzed conchiolin protein (HCP) derived from pearl and nacre extracts exerts skin-lightening effects; however, the underlying molecular mechanisms are not fully understood. Herein, we investigated the effect of HCP on melanogenesis and the signalling pathways involved. B16F10 cells and PIG cells were treated with HCP to verify its ability to inhibit melanin. Western Blot, immunofluorescence, and flow cytometry methods were performed to investigate the effect of HCP on melanogenesis signalling pathway proteins. The inhibitors were used to further validate the effect of HCP on PKA/CREB and MEK/ERK signalling pathways. To further evaluate the whitening ability of HCP, changes in melanin were detected using 3D melanin skin model and zebrafish model. HCP was found to significantly inhibit melanin synthesis and decrease the expression of melanogenesis-related proteins, such as microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein-2, in a dose-dependent manner. Additionally, we revealed that HCP suppresses melanogenesis via the regulation of the PKA/cAMP response element-binding (CREB) and MEK/extracellular signalling-regulated kinase (ERK) signalling pathways. Using 3D melanin skin models, we demonstrated that HCP can achieve skin-lightening effects by improving apparent chroma, increasing apparent brightness, and inhibiting melanin synthesis. Furthermore, HCP exhibits skin-whitening effects in a zebrafish model. These results suggest that HCP suppresses the melanogenesis signalling cascade by inhibiting the PKA/CREB, MEK/ERK signalling pathway and downregulating MITF and its downstream signalling pathways, resulting in decreased melanin synthesis. In summary, HCP is a potential anti-pigmentation agent with promising applications in cosmetics and pharmaceutical products.

Progression from in vivo validation to in vitro screening in hazard assessment for leukoderma-inducible chemicals

Chemicals are representative environmental factors that affect human health. Recently, external exposure to a chemical of rhododenol (RD) caused chemical leukoderma, an acquired patchy hypopigmentation, in about 20,000 Asian people. The development of a hazard assessment system for accurate determination of leukoderma-inducible chemicals is required for the prevention of such tragedies. Case studies in humans have shown 6 chemicals, including RD, with a constitutive leukoderma-inducible potency and 3 chemicals with a photosensitive but not a constitutive leukoderma-inducible potency. In this study, the 6 positive and 3 negative control chemicals with or without constitutive leukoderma-inducible potencies were investigated by our previously developed in vivo hazard assessment system using tail skin of mice. Based on the results of validation, this study aimed to develop an in vitro hazard assessment system to correctly determine chemicals with a constitutive leukoderma-inducible potency. As expected, external exposure to the 6 positive control chemicals, but not external exposure to the 3 negative control chemicals, resulted in development of constitutive leukoderma in mouse tail skin with a decreased level of skin melanin and decreased number of melanocytes. Moreover, the 6 positive and 3 negative control chemicals were correctly distinguished by the presence or absence of endoplasmic reticulum (ER) stress induction, but not by tyrosinase-dependent cell death or production of reactive oxygen species (ROS), in immortalized normal melanocytes. The hazard assessment system using tail skin could be a solid in vivo tool to reliably determine the chemical potency of a chemical for constitutive leukoderma induction. The hazard assessment system focusing on ER stress induction in normal melanocytes might be a novel and convenient in vitro tool for accurately evaluating chemicals with leukoderma-inducible potencies. Thus, this study contributed to environmentology through the development of a screening system for preventing an environmental factor-related disease.

Mechanism of the wine pomace tannin in hyperpigmentation inhibition: Impact on signaling pathways, cell proliferation, and tyrosinase activity

After winemaking, tannins with high polymerization remain in the pomace. Utilizing these tannin fractions is a concern for the wine industry. While tannins show potential in treating hyperpigmentation, their mechanisms in vivo and at the cellular level are unclear. Herein, pomace tannin fractions (PTFs) were isolated post-winemaking. Nuclear magnetic resonance spectroscopy and mass spectrometry analysis showed PTFs were composed of (epi)catechin gallate and (epi)catechin as terminal and extensional units, with polymerization degrees of 10, 16, and 35. In vivo studies demonstrated that PTFs removed ∼76 % of skin melanin, comparable to hydroquinone. The inhibition by PTFs is due to: (1) Inhibition of the Wnt and melanogenesis pathways, downregulating key melanin synthesis proteins (TYR, TYRP1, TYRP2); (2) Inducing cell cycle arrest at the G1/S checkpoint, disrupting DNA, decreasing mitochondrial membrane potential and integrity, and slowing melanocyte proliferation; (3) Superior tyrosinase inhibitory activity by binding to tyrosinase, chelating copper ions, and demonstrating antioxidant properties. These findings suggest that PTFs inhibit melanin synthesis by the combination of the above mentioned ways, supporting the medical use of winemaking tannins.

YTHDF2 Regulates Advanced Glycation End Products-Induced Melanogenesis through Inhibiting A20 Expression in Human Dermal Fibroblasts.

Fibroblast A20 suppresses advanced glycation end products (AGEs)-induced melanogenesis by inhibiting NLRP3 inflammasome activation. AGEs repress A20 expression and significantly m6A-methylate A20 mRNA in fibroblasts. YTHDF2 is the most studied m6A reader protein and can accelerate degradation of m6A-modified mRNA. Whether YTHDF2 regulates AGEs-induced A20 expression and pigmentation is unknown. In this study, we confirmed that YTHDF2 inversely regulated AGEs-BSA-inhibited A20 expression but facilitated AGEs-BSA-activated NF-κB signaling and NLRP3 inflammasome in fibroblasts via YTHDF2 knockdown and overexpression experiments. Mechanistically, YTHDF2 bound to m6A-modified A20 mRNA induced by AGEs-BSA and increased its degradation. Moreover, fibroblast YTHDF2 robustly promoted AGEs-BSA-induced IL-18 level in coculture supernatants and melanin content, tyrosinase activity, and expression of microphthalmia-associated transcription factor and tyrosinase in melanocytes, which were significantly blocked by IL-18 binding protein. Further, fibroblast YTHDF2 markedly increased AGEs-BSA-induced epidermal melanin level in cocultured ex vivo skin and MAPKs activation in melanocytes. Importantly, upregulated dermal YTHDF2 expression was negatively correlated with dermal A20 level and positively associated with both epidermal melanin and dermal AGEs content in sun-exposed skin and lesions of melasma and solar lentigo. These findings suggest that fibroblast YTHDF2 positively regulates AGEs-induced melanogenesis mainly via A20/ NF-κB /NLRP3 inflammasome/ IL-18 /MAPKs axis in an m6A-dependent manner and functions in photoaging-induced hyperpigmentation skin disorders.

The effect of betel nut extract on melanin pigment levels in rats' skin exposed to Ultraviolet B radiation

This study aims to analyze the effect of areca nut extract on the amount of melanin pigment in the skin of Wistar rats exposed to ultraviolet-B light. The research method used was post-test with control group design. The total sample of white rats used was 20 rats, which were divided into 4 groups with each group consisting of 5 rats. The cream preparation was made using cold cream base. The rats were then exposed to UVB with a certain intensity for 5 days, characterized by erythema as a result of UVB absorption into the epidermis. Each group of treated rats received base cream, 10% areca nut extract cream, and 15% areca nut extract cream topically for 14 days before termination on day 15. The collected data were then tabulated and analyzed. To determine significant differences or influences between the test groups, analysis was carried out with t-test or Independent Samples T-Test approach at 95% confidence level (p < 0.05). The results of the analysis showed that the administration of areca nut extract was effective in reducing the amount of melanin pigment in the skin of Wistar rats exposed to Ultraviolet-B light. From histopathological observations, the administration of areca nut extract with a concentration of 15% is effective in removing or fading melanin pigments in the skin exposed to Ultraviolet-B light and the results of damaged skin melanin pigments appear in the epidermis of rat skin barely visible grain.

Hemoglobin Concentration as an Indicator of Skin Radiation Damage During Radiation Therapy Treatments

Acute radiation dermatitis (ARD) is the most common side effect reported by patients undergoing radiation therapy (RT). Currently, the assessment of the severity of the reaction is based on the visual assessment of the skin, which is a subjective method, depending on many factors. The main aim of this study was to investigate the usefulness of hyperspectral imaging (HSI) in the assessment of ARD and find physiological factors that could be correlated with ARD. In this clinical pilot trial, weekly acquisitions of hyperspectral camera images of irradiated skin were performed for 5 weeks of RT and at the posttreatment follow-up visit which took place 30 to 40 days after the last fraction of RT. At the same time, the severity of radiodermatitis was assessed based on the criteria of the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE). The content and concentration of chromophores in irradiated skin were quantitatively determined using a hyperspectral camera. The use of HSI supported by image analysis and processing methods allowed for the determination of the content and distribution of hemoglobin and melanin in the irradiated skin. It was found that the hemoglobin concentration is correlated with the subjective assessment made according to the CTCAE protocol. HSI is a sensitive and specific method of analyzing the concentration of chromophores in the skin, including hemoglobin. A clear correlation was found between hemoglobin concentration and CTCAE v.5 scale because of which HSI can be considered as an objective method of skin assessment during RT.

Tokishakuyakusan alleviates ultraviolet-induced skin pigmentation by decreasing the expression of melanogenesis-related enzymes

Ethnopharmacological relevanceTokishakuyakusan (TSS), a traditional Kampo medicine, can effectively alleviate symptoms unique to women, such as menstrual pain and menopausal symptoms, and this effect is believed to be related to its ability to increase the secretion of female hormones. TSS is also believed to be effective against skin pigmentation. However, no studies have examined the effect of TSS on pigmentation. Aim of the studyIn this study, we conducted basic research to determine the effects of TSS on pigmentation. Materials and methodsFemale HRM-2 mice were given free access to a normal diet or a TSS-containing diet for 7 weeks. For 3 weeks starting from the 4th week of treatment, the back of the skin was irradiated with ultraviolet (UV) light, and the melanin level was measured. The expression levels of melanogenesis-related genes and inflammatory markers in the skin were analyzed. ResultsThe melanin level in the skin of the mice exposed to UV radiation was approximately three times greater than that in the skin of the mice in the non-UV-irradiated group, confirming pigmentation due to UV irradiation. The protein expression levels of tyrosinase (Tyr), tyrosinase-related protein-1 (Tyrp1), and dopachrome tautomerase (Dct), which are important for melanin production, were significantly greater in the UV irradiation group than in the non-UV irradiation group. In contrast, the amount of skin melanin in the mice treated with TSS was significantly lower than that in the UV-irradiated group, and the expression levels of melanogenesis-related enzymes were also lower. Furthermore, TSS significantly decreased the expression of microphthalmia transcription factor (Mitf), a transcription factor for melanogenesis-related enzymes, and the inflammatory cytokines interleukin-1β and interleukin-6. ConclusionsTSS inhibits melanin production in melanocytes by suppressing the increase in the expression of melanogenesis-related enzymes caused by UV irradiation. These findings suggested that this effect of TSS is exerted through the combined regulation of MITF expression and anti-inflammatory responses.

Combining large-spot low-fluence 1064-nm and fractional 1064-nm picosecond lasers for promoting protective melanosome autophagy via the PI3K/Akt/mTOR signalling pathway for the treatment of melasma.

Melasma is a common condition of hyperpigmented facial skin. Picosecond lasers are reported to be effective for the treatment of melasma. We aimed to identify the most effective therapeutic mode and elucidate the potential molecular mechanisms of picosecond lasers for the treatment of melasma. Female Kunming mice with melasma-like conditions were treated using four different picosecond laser modes. Concurrently, invitro experiments were conducted to assess changes in melanin and autophagy in mouse melanoma B16-F10 cells treated with these laser modes. Changes in melanin in mouse skin were detected via Fontana-Masson staining, and melanin particles were evaluated in B16-F10 cells. Real-time polymerase chain reaction and western blotting were used to analyse the expression levels of melanosome and autophagy-related messenger ribonucleic acid (mRNA) and proteins. A combination of large-spot low-fluence 1064-nm and fractional 1064-nm picosecond lasers resulted insignificant decreases in melanin as well as in mRNA and protein expression of melanin-synthesizing enzymes (TYR, TRP-1 and MITF). This combination also led to increased expression of the autophagy-related proteins, Beclin1 and ATG5, with a marked decrease in p62 expression. Intervention with the PI3K activator, 740 Y-P, increased TYR, TRP-1, MITF, p-PI3K, p-AKT, p-mTOR and p62 expression but decreased the expression of LC3, ATG5 and Beclin1. A combination of large-spot low-fluence 1064-nm and fractional 1064-nm picosecond lasers proved more effective and safer. It inhibits melanin production, downregulates the PI3K/AKT/mTOR pathway, enhances melanocyte autophagy and accelerates melanin metabolism, thereby reducing melanin content.

Newly identified peptide Nigrocin-OA27 inhibits UVB induced melanin production via the MITF/TYR pathway

Melasma is a common skin disease induced by an increase in the content of melanin in the skin, which also causes serious physical and mental harm to patients. In this research, a novel peptide (Nigrocin-OA27) from Odorrana andersonii is shown to exert a whitening effect on C57 mice pigmentation model. The peptide also demonstrated non-toxic and antioxidant capacity, and can significantly reduce melanin content in B16 cells. Topical application effectively delivered Nigrocin-OA27 to skin's epidermal and dermal layers and exhibited significant preventive and whitening effects on the UVB-induced ear pigmentation model in C57 mice. The whitening mechanism of Nigrocin-OA27 may be related to reduced levels of the microphthalmia-associated transcription factor and the key enzyme for melanogenesis-tyrosinase (TYR). Nigrocin-OA27 also inhibited the catalytic activity by adhering to the active core of TYR, thereby reducing melanin formation and deposition. In conclusion, Nigrocin-OA27 may be a potentially effective external agent to treat melasma by inhibiting aberrant skin melanin synthesis.

In vitro and split-faced placebo-controlled in vivo study on the skin rejuvenating effects of cream loaded with bioactive extract of Indigofera argentea Burm.f.

The bioactive extracts of traditional medicinal plants are rich in polyphenols and help to rejuvenate skin. The study was designed to assess the skin rejuvenating effects of a stable cream enriched with 4% I. argentea (IaMe) extract. The quantity of polyphenols by spectrophotometric methods was TPC, 101.55 ± 0.03mg GAE/g and total flavonoid content; 77.14 ± 0.13mg QE/g, while HPLC-PDA revealed gallic acid; 4.91, chlorogenic acid 48.12, p-coumaric acid 0.43, and rutin 14.23μg/g. The significant results of biological activities were observed as DPPH; 81.81% ± 0.05%, tyrosinase; 72% ± 0.23% compared to ascorbic acid (92.43% ± 0.03%), and kojic acid (78.80% ± 0.19%) respectively. Moreover, the promising sun protection effects Sun protection factor of extract (20.53) and formulation (10.59) were observed. The active cream formulation (w/o emulsion) was developed with liquid paraffin, beeswax, IaMe extract, and ABIL EM 90, which was stable for 90 days as shown by various stability parameters. The rheological results demonstrated the active formulation's non-Newtonian and pseudo-plastic characteristics and nearly spherical globules by SEM. The IaMe loaded cream was further investigated on human trial subjects for skin rejuvenating effects and visualized in 3D skin images. Herein, the results were significant compared to placebo. IaMe formulation causes a substantial drop in skin melanin from -1.70% (2 weeks) to -10.8% (12 weeks). Furthermore, it showed a significant increase in skin moisture and elasticity index from 7.7% to 39.15% and 2%-30%, respectively. According to the findings, Indigofera argentea extract has promising bioactivities and skin rejuvenating properties, rationalizing the traditional use and encouraging its exploitation for effective and economical cosmeceuticals.

Investigating Skin Cancer Diagnosis Using a Webcam-based Microcontroller System

Skin cancer can spread fast to nearby tissue and other parts of the human body if it's not diagnosed early. Most are curable only if skin cancer is found and treated in the early stages. Therefore, it's essential to seek a casual way of early diagnosis. This paper assesses a prototype system for skin cancer detection using an Arduino with an ArduCam Mega 5MP, benchmarked against smartphone diagnosis. Bandpass filters capture skin images at red (650 nm), green (532 nm), and blue (450 nm) wavelengths, measuring reflectance values. The approach aims to quantitatively determine skin melanin, oxyhemoglobin, and deoxyhemoglobin levels, aiding in various skin lesions' diagnosis. Evaluation involves comparing pixel reflectance values of images taken by smartphones and the prototype using a 3D mesh grid. Applying the modified Lambert-Beer law to reflectance values of moles, pimples, scars, scabs, and traces predicts relative levels of skin components. The system shows an 87% match with the smartphone standard, demonstrating high reliability. Further study might be needed to clarify the confirmation with clinical cases.

Evaluation of the efficacy of a sunscreen containing ultra-long UVA1 and other UVR broad-spectrum filters on skin barrier protection and melanin content reduction in Chinese adults: A single-center study.

The protection for ultra-long UVA1 is lacked in the market, posing potential damage from ultra-long UVA1 irradiation. The study aims to evaluate the efficacy of a sunscreen containing multiple components, especially Mexoryl® 400 for improving skin barrier function and reducing melanin content. This single-center study included adults with sensitive and normal skin in China in November 2022. Participants received the test sunscreen for 4 weeks. Melanin and hemoglobin content, sebum secretion skin hydration, and trans-epidermal water loss were evaluated at T0d, T7d, and T28d. The self-assessment was done at T15min, T7d, and T28d. Sixty participants were included, including 30 self-claimed sensitive skin in the sunscreen group. The sunscreen demonstrated significant improvements in skin parameters. Skin redness reduced by 9.84% at T28d, sebum content in the forehead area decreased by 22.70% at T28d, and skin stratum corneum hydration increased by 38.44% at T28d, p < 0.001 respectively. Most notably, skin melanin content significantly reduced by 13.49% after 4 weeks' usage (p < 0.001). No adverse reactions were reported in either group. The study sunscreen improved the skin condition by decreasing the melanin content, regulating skin barrier function, and achieving a balance of skin hydration and sebum secretion.