Melanin Overproduction Research Articles

Inhibitory Effects of Fermented Sprouted Oat Extracts on Oxidative Stress and Melanin Overproduction.

Hyperpigmentation occurs due to irregular secretion of melanin pigment in the skin. This can affect quality of life depending on its severity, so prevention and management are essential. Oats (Avena sativa L.), a grain consumed worldwide, are known to offer improved health benefits upon germination and fermentation. This study is aimed to investigate the protective effects of lactobacilli-fermented sprouted oat extracts on oxidative stress and melanin overproduction in vitro. The anti-melanogenic effect was investigated using melanin content and tyrosinase activity assays in B16F10 cells, as well as a mushroom tyrosinase-based enzyme inhibition assay. The results showed that L. casei-fermented oat extracts were the most effective for reducing melanin formation by reducing the mRNA expression of microphthalmia-associated transcription factor, tyrosinase, and tyrosinase-related protein 2. Furthermore, L. casei fermentation was effective in improving the total phenolic, flavonoid, and avenanthramide A contents of sprouted oat extracts. The results also demonstrated the antioxidant effects of L. casei-fermented sprouted oat extracts in promoting DPPH radical-scavenging activity, superoxide dismutase-like activity, and reduction in reactive oxygen species levels. Overall, the findings indicate that fermented sprouted oat extracts are promising candidates for antioxidant and anti-hyperpigmentation treatments.

Targeted intradermal delivery of alpha-arbutin-loaded dissolving polymeric microneedles visualized by three-dimensional Orbitrap secondary ion mass spectrometry (3D OrbiSIMS)

Hyperpigmentation, a prevalent dermatological condition characterized by melanin overproduction, poses treatment challenges due to the hydrophilicity of alpha-arbutin, a widely utilized tyrosinase inhibitor. This study investigates the efficacy of dissolving microneedles (DMNs) in augmenting skin permeation for alpha-arbutin delivery to the targeted epidermal site.Porcine full-thickness skin was employed in a 24-hour Franz cell study, commencing with the assessment of commercial alpha-arbutin-containing products. Solid steel microneedles (CMNs) from Dermapen® were utilized as both pre- and post-treatment modalities to evaluate the influence of different applications on alpha-arbutin delivery. Additionally, alpha-arbutin-loaded polyvinylpyrrolidone-co-vinyl acetate (PVPVA) DMNs, containing 2 % w/w alpha-arbutin, were fabricated and examined for their permeation-enhancing capabilities. HPLC analysis and 3D Orbitrap Secondary Ion Mass Spectrometry (OrbiSIMS) were employed to quantify and visualize alpha-arbutin in various Franz cell components.Results indicate that alpha-arbutin permeation to the skin was restricted (less than 1 %) without microneedle application and significantly increased by 6-fold (4–5 %) with post-treatment CMNs and DMNs, but not with pre-treatment CMNs. Notably, DMNs exhibited a more sustainable and robust capacity than post-treatment CMNs. OrbiSIMS imaging analysis revealed that DMNs visually enhance skin permeation of alpha-arbutin by delivering the compound to the basal layer of the targeted skin location. Overall, this study underscores the potential of DMNs as a promising delivery system for promoting targeted intradermal delivery of alpha-arbutin, providing a comprehensive exploration of various methodologies to identify innovative and improved microneedle approaches for alpha-arbutin permeation.

Atractylodes lancea rhizome derived exosome-like nanoparticles prevent alpha-melanocyte stimulating hormone-induced melanogenesis in B16-F10 melanoma cells

Aberrant melanin overproduction can significantly impact an individual's appearance and cause mental and psychological distress. Current inhibitors of melanin production exert harmful side effects due to inadequate selectivity; thus a need to develop more selective melanin synthesis inhibitors is necessary. Extracellular vesicles are important agents of intercellular signalling in prokaryotes and eukaryotes. Recently, plant-derived nanoparticles, similar to mammalian exosomes, have attracted attention for their use in health research. In this study, to investigate the potential of plant-derived exosome-like nanoparticles (ELNs) as inhibitors of melanin production, we used hot water to extract ELNs from the rhizome of Atractylodes lancea (A-ELNs). The size of A-ENLs ranged from 34 to 401 nm and carried three microRNA: ath-miR166f, ath-miR162a-5p, and ath-miR162b-5p. These A-ENLs were applied to B16-F10 melanoma cells treated with α-melanocyte-stimulating hormone (α-MSH). After A-ELNs were taken up by B16-F10 cells, their melanin levels were significantly reduced. Furthermore, A-ELNs significantly reduced tyrosinase activity in B16-F10 cells and mRNA expression of microphthalmia-associated transcription factor (Mitf), tyrosinase, tyrosinase-related protein 1, and DOPA chrome tautomerase. These results suggest that A-ELN suppresses melanogenic enzymes expression by downregulating Mitf, thereby inhibiting melanin synthesis. Hence, A-ELN can be developed into a novel topical drug after additional studies and optimization.

Anti-Melanogenic and Antioxidant Activity of Bifidobacterium longum Strain ZJ1 Extracts, Isolated from a Chinese Centenarian.

Melanin produced by melanocytes protects our skin against ultraviolet (UV) radiation-induced cell damage and oxidative stress. Melanin overproduction by hyperactivated melanocytes is the direct cause of skin hyperpigmentary disorders, such as freckles and melasma. Exploring natural whitening agents without the concern of toxicity has been highly desired. In this study, we focused on a Bifidobacterium longum strain, ZJ1, isolated from a Chinese centenarian, and we evaluated the anti-melanogenic activity of the distinctive extracts of ZJ1. Our results demonstrated that whole lysate (WL) and bacterial lysate (BL) of ZJ1 ferments efficiently reduce α-melanocyte-stimulating hormone (α-MSH)-induced melanin production in B16-F10 cells as well as the melanin content in zebrafish embryos. BL and WL downregulate melanogenesis-related gene expression and indirectly inhibit intracellular tyrosinase activity. Furthermore, they both showed antioxidant activity in a menadione-induced zebrafish embryo model. Our results suggest that ZJ1 fermentation lysates have application potential as therapeutic reagents for hyperpigmentary disorders and whitening agents for cosmetics.

Targeting senescent dermal fibroblasts responsible for hyperactive melanocytes in melasma

Targeting senescent dermal fibroblasts responsible for hyperactive melanocytes in melasma

Radiofrequency Irradiation Attenuated UVB-Induced Skin Pigmentation by Modulating ATP Release and CD39 Expression.

Hyperpigmentation stimulated by ultraviolet (UV)-induced melanin overproduction causes various cosmetic problems. UV radiation's activation of the cyclic adenosine monophosphate (cAMP)-mediated cAMP-dependent protein kinase (PKA)/cAMP response element-binding protein (CREB)/microphthalmia-associated transcription factor (MITF) pathway is the main pathway for melanogenesis. However, the secretion of adenosine triphosphate (ATP) from keratinocytes due to UV radiation also leads to melanogenesis. Adenosine, converted from ATP by CD39 and CD73, can activate adenylate cyclase (AC) activity and increase intracellular cAMP expression. cAMP-mediated PKA activation results in dynamic mitochondrial changes that affect melanogenesis via ERK. We evaluated whether radiofrequency (RF) irradiation could decrease ATP release from keratinocytes and suppress the expression of CD39, CD73, and A2A/A2B adenosine receptors (ARs) and the activity of AC and downregulate the PKA/CREB/MITF pathway, which would eventually decrease melanogenesis in vitro in UV-irradiated cells and animal skin. Our results indicate that RF decreased ATP release from UVB-irradiated keratinocytes. When conditioned media (CM) from UVB-irradiated keratinocytes (CM-UVB) were administered to melanocytes, the expressions of CD39, CD73, A2A/A2BARs, cAMP, and PKA increased. However, the expression of these factors decreased when CM from UVB and RF-irradiated keratinocytes (CM-UVB/RF) was administered to melanocytes. The phosphorylation of DRP1 at Ser637, which inhibits mitochondrial fission, increased in UVB-irradiated animal skin and was decreased by RF irradiation. The expression of ERK1/2, which can degrade MITF, was increased using RF treatment in UVB-irradiated animal skin. Tyrosinase activity and melanin levels in melanocytes increased following CM-UVB administration, and these increases were reversed after CD39 silencing. Tyrosinase activity and melanin levels in melanocytes were decreased by CM-UVB/RF irradiation. In conclusion, RF irradiation decreased ATP release from keratinocytes and the expressions of CD39, CD73, and A2A/A2BARs, which decreased AC activity in melanocytes. RF irradiation downregulated the cAMP-mediated PKA/CREB/MITF pathway and tyrosinase activity, and these inhibitory effects can be mediated via CD39 inhibition.

Mechanism of melanogenesis inhibition by Keggin-type polyoxometalates.

Abnormal melanin overproduction can result in hyperpigmentation syndrome in human skin diseases and enzymatic browning of fruits and vegetables. Recently, our group found that Keggin-type polyoxometalates (POMs) can efficiently inhibit tyrosinase activity. However, it remains unclear whether Keggin-type POMs exhibit optimal effects in vivo. Additionally, the inhibitory effect and mechanism of action of POMs on cellular tyrosinase activity and melanogenesis have been rarely reported. Here we demonstrate that our screened and synthesised PMo11Zn and GaMo12 show superior inhibitory effects on melanin formation as well as inhibition of cellular tyrosinase activity compared to other Keggin-type POMs. Intriguingly, we reveal that Keggin-type POMs competitively bind to tyrosinase mainly through more interactions with Cu2+ ions and the amino acid residue is capable of forming van der Waals, cation-π and hydrogen bonds, resulting in a reversible non-covalent complex formation. Our findings provide valuable insights into the design, synthesis and screening of polyoxometalates as multifunctional metallodrugs and food preservatives against hyperpigmentation.

Efficacy and Best Mode of Delivery for Tranexamic Acid in Post-Inflammatory Hyperpigmentation: A Systematic Review.

Post-inflammatory hyperpigmentation (PIH) is skin hyperpigmentation that occurs due to any inflammatory condition. Triggering the melanocytes by inflammation leads to melanin overproduction and deposition. Tranexamic acid (TXA) is an antifibrinolytic medication prescribed to treat bleeding. Recently, there are some studies about the use of TXA in the treatment of PIH. The aim of this study is to identify the efficacy and the best mode of delivery for tranexamic acid in the treatment of PIH. This systematic review is reported in accordance with PRISMA guidance. We included all relevant English-language studies that were published up to September 2022 in the following electronic databases: Cochrane Library, PubMed, Embase, and Google Scholar. The initial search yielded 61 articles, 9 of which were included after applying inclusion and exclusion criteria. The systematic review included a total of 196 patients who were over the age of 16 years old. Tranexamic acid was delivered orally in 4 studies, topically in 2 studies, and both simultaneously in 1 study. In addition, intradermal injection was used in 2 other studies. Almost all studies advocated the use of all routes for accelerating the clearance of hyperpigmentation with more favor towards topical and intradermal routes due to their mild reported side effects when compared to oral routes. Intradermal TXA is considered the best route, which exhibits fewer side effects with less cost and excellent outcomes, while oral TXA is found to be less preferable than other routes due to the incidence of undesirable adverse events.

31037 Assessment of actives and formula on antipigmentation efficacy

Hyperpigmentation is a skin condition resulting from overproduction of melanin, the pigment produced by melanocytes. Melanocytes reside at the basal layer of the epidermis, producing melanin and transferring it to surrounding keratinocytes to protect the skin from UV damage. As we get older, irregularities develop, such as dark spots and uneven skin tone. Simple topical treatments against melanin overproduction are not always effective, due to skin irritability of potent ingredients or lack of penetration into the skin. A two-step approach was designed to screen for efficacious antipigmentation actives and validate performance in a finished formulation. First, potentially effective ingredients were screened for cytotoxicity and melanin synthesis inhibition using darkly pigmented normal human melanocytes. One of the efficacious ingredients identified without causing melanocyte cytotoxicity is bisabolol. Next, bisabolol is formulated into formulas with additional beneficial ingredients, and assessed on a 3D skin model for antipigmentation efficacy as well as skin irritability. MelanoDerm model was used to evaluate two different finished formulations that include bisabolol. MelanoDerm was treated with 2 final formulas as well as 2 placebo control formulas, which lacked bisabolol. The positive control was 2% kojic acid. The efficacy was assessed after 2 weeks of treatments. Compared with placebo controls, formula with bisabolol inhibited melanin synthesis. Additionally, collected media was used to evaluate skin irritation potential by assessing IL-1a release by ELISA. Final formulas had minimal impact on IL-1a release. Utilizing both monolayer melanocytes and MelanoDerm, efficacious anti-pigmentation products were validated without concerns on skin irritation.

Synthesis of Fluorinated <i>N</i>- Benzylaniline Derivatives and Evaluations on Anti-Tyrosinase and Anti-Melanogenic Activities

Melasma, freckles, age spots, and acne scars are common aesthetic problems resulted from melanin overproduction. This study aimed to develop new skin depigmenting compounds and characterize on melanin inhibition activities. The fluorinatedN-benzylaniline derivatives were synthesized and evaluated for theirin vitroanti-tyrosinase activity. Derivatives withp-fluorine monosubstition,N-(4-fluorobenzyl)-3-fluoro-4-methoxyaniline (3d), was the most potent inhibitor against mushroom tyrosinase with 75.4 ± 0.34 % inhibition at 500 µM which was as potent as the positive control, kojic acid. Furthermore, compound3dexhibited superior anti-melanogenic activity in α-MSH-induced B16F10 murine melanoma cells, compared to kojic acid. Therefore,N-(4-fluorobenzyl)-3-fluoro-4-methoxyaniline (3d) was proposed as a new agent effective against skin hyperpigmentation.

In Vitro Photoprotective, Anti-Inflammatory, Moisturizing, and Antimelanogenic Effects of a Methanolic Extract of Chrysophyllum lucentifolium Cronquist.

UVB exposure causes DNA mutation and ROS generation, which lead to skin photoaging, skin wrinkling, skin sagging, and uneven skin pigmentation. ROS activate the NF-κB and MAPK signaling pathways leading to production of inflammatory molecules such as COX-2, collagen-degrading proteins such as matrix metalloproteinases (MMPs), and moisture-deficiency-related proteins such as hyaluronidases (HYALs). UVB exposure also induces irregular skin pigmentation though melanin overproduction, related to CREB transcription factor activity and transcription of melanogenesis genes. Here, we demonstrate that Chrysophyllum lucentifolium methanol extract (Cl-ME) has antioxidant activity; it dose-dependently decreased the expression of COX-2, MMP-1, MMP-9, HYAL-1, and HYAL-4 by downregulating the NF-κB (IKKα/β, IκBα) and MAPK (ERK, JNK, and p38) pathways and increased the expression of Col1a1, which encodes a protein important for maintaining skin elasticity. Cl-ME also showed promising antimelanogenic activity by decreasing the expression of CREB, a transcription factor, which in turn inhibited the expression of genes encoding tyrosinase, MITF, TYRP1, and TYRP2. In summary, a methanol extract of C. lucentifolium exhibited antiphotoaging and antimelanogenic activity and could be useful in the cosmeceutical industry.

The Ethanol Extract of Musa sapientum Linn. Peel Inhibits Melanogenesis through AKT Signaling Pathway

Hyperpigmentation caused by melanin overproduction can be induced by UV radiation. The quest for effective depigmenting agents continues because many anti-melanin agents have restricted use and/or produce side-effects. The present study was aimed to investigate the inhibitory activity of Musa sapientum Linn. (AA group) peel ethanol extracts (MPE) on α-melanocyte stimulating hormone (α-MSH)-induced melanin production. In addition, the molecular mechanism related to this process was examined in B16F10 mouse melanoma cells. The results indicated that MPE remarkably inhibited melanogenesis in α-MSH-stimulated B16F10 cells. Microphthalmia-associated transcription factor (MITF) and tyrosinase expressions were suppressed by MPE in a concentration-dependent manner. In addition, MPE significantly decreased the expression of melanosome transfer protein markers (Rab27a and Pmel17) in a dose-dependent manner. This study found that the elevated phosphorylation of AKT in the B16F10 cells was diminished by MPE treatment. Furthermore, microtubule-associated protein 1 light chain 3 (LC3)-II and p62 (autophagy markers) were affected after the B16F10 cells were treated with MPE. This study demonstrated that MPE might be an effective agent for anti-melanogenesis through the AKT pathway, subsequently diminishing MITF expression and tyrosinase enzyme family production. The findings indicated that MPE could potentially serve as a depigmenting agent in cosmeceuticals.

Anti-Melanogenic Effects of Korean Red Ginseng Oil in an Ultraviolet B-Induced Hairless Mouse Model.

A ‘remedy for all’ natural product widely known in the Korean Peninsula is called Panax Ginseng Meyer. Globalization represents a persistent risk to the ozone layer, leading to bountiful amounts of Ultra-Violet B beams (UVB). The variety in human skin hues is ascribed to the characteristic color called Melanin. However, Melanin overproduction due to UVB beams promotes skin staining and tumorigenesis, a process called photo aging, which damages skin quality. To assess the effects of Korean Red Ginseng Oil (KGO) on photo aging, the murine melanoma cell lines B16/F10 were used in vitro and HRM-2 hairless mice exposed to UVB were studied in vivo. Our results revealed that KGO reduced tyrosinase activity and melanin production in B16/F10 cells along with the suppression of upstream factors involved in the melanin production pathway, both transcriptionally and transitionally. In the in vivo studies, KGO suppressed the expression of Matrix Metalloproteinase (MMP) and Interleukins along with a reduction of depth in wrinkle formation and reduced collagen degradation. Moreover, the feed intake and feed efficiency ratio that decreased as a result of UVB exposure was also improved by KGO treatment. In light of our results, we conclude that KGO can have considerable benefits due to its various properties of natural skin enhancement.

Clinical efficacy of dissolvable microneedles armed with anti-melanogenic compounds to counter hyperpigmentation.

Hyperpigmentation is a complex physiological process associated with alterations of skin color due to melanin overproduction and distribution. Both intrinsic and extrinsic factors influence discoloration with the involvement of multiple pathways in cooperative manners. Restoring natural skin color requires a multi-targeted approach. Latest advances in anti-melanogenic compounds and microneedle delivery system have presented opportunities for tackling hyperpigmentationsuccessfully. This work was aimed at assessing the dermal tolerability and efficacy of hyaluronic acid-based microneedle patches loaded with anti-melanogenic actives for improvements of skin discoloration. The test products consist of hyaluronic acid with niacinamide, ascorbic acid 2-glucoside, tranexamic acid, resveratrol, 4-n-butyl-resorcinol, and Halidrys siliquosa extract. In a monocentric 12weeks clinical trial, the HA-MNs patches were applied to the affected areas of the faces on subjects with hyperpigmented skin. The color properties of the skin were analyzed spectrophotometrically. The products were tolerated remarkably; none of the subjects informed any primary or cumulative skin responses. Evaluation of color related measurable skin properties provided insight into the general effectiveness: The individual topology measurements showed 51.4% noticeable improvements in hyperpigmented zones, which were also in good agreement with the personal impressions of the subjects determined by questionnaires before and after the treatments. The concentrated blends of actives in microneedle patches act in a multi-targeted manner, and they could be worked in a complementary fashion for the improvement of skin color and appearance. The study has established the overall convenience of the HA-MNs with the formulation of anti-melogenic compounds against skin discoloration.

Exploring the potential effect and mechanisms of protocatechuic acid on human hair follicle melanocytes.

This study aims to evaluate the effect of protocatechuic acid (PCA) on human hair follicle melanocytes (HFM). Normal primary HFM were isolated and cultured till logarithmic period of second passage, then treated with different concentrations of PCA (0.1-200 μmol L-1) to study the cell proliferation, melanin contents, tyrosinase activity and protein and mRNA expression of melanogenic genes (tyrosinase-related protein 1 (TRP-1), tyrosinase-related protein 2 (TRP-2), and microphthalmia-associated transcription factor (MITF)) in the cultured HFM. In addition, we have also measured the contents of superoxide dismutase (SOD) and glutathione (GSH) in PCA treated HFM. Vitamin C was used as a positive control. The result showed that PCA can decrease the synthesis of melanin and the tyrosinase activity with IC50 = 8.9 μmol L-1 and IC50 = 6.4 μmol L-1, respectively, at the treatment time of 24 hours, without inducing any cytotoxicity in HFM cells. In addition, the mRNA transcription and protein expression levels of TRP-1, TRP-2 and MITF significantly decreased with a dose-dependent manner after 24-hour PCA treated in HFM cells. Furthermore, PCA has significantly increased the SOD and GSH activity in a dose-dependent manner for 24-hour PCA treatment. This study suggested that PCA has an inhibitory effect on the production of melanin through down-regulation of the expression of melanogenesis-related protein and the effect of anti-oxidation, which could be useful for the therapy of melanin overproduction or skin whitening.

Safflospermidines from the bee pollen of Helianthus annuus L. exhibit a higher in vitro antityrosinase activity than kojic acid

BackgroundOzone deterioration in the atmosphere has become a severe problem causing overexposure of ultraviolet light, which results in humans in melanin overproduction and can lead to many diseases, such as skin cancer and melasma, as well as undesirable esthetic appearances, such as freckles and hyperpigmentation. Although many compounds inhibit melanin overproduction, some of them are cytotoxic, unstable, and can cause skin irritation. Thus, searching for new natural compounds with antityrosinase activity and less/no side effects is still required. Here, bee pollen derived from sunflower (Helianthus annuus L.) was evaluated. Materials and methodsSunflower bee pollen (SBP) was collected from Apis mellifera bees in Lopburi province, Thailand in 2017, extracted by methanol and sequentially partitioned with hexane and dichloromethane (DCM). The in vitro antityrosinase activity was evaluated using mushroom tyrosinase and the half maximal inhibitory concentration (IC50) is reported. The antioxidation activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and reported as the half maximal effective concentration. Two pure compounds with antityrosinase activity were isolated by silica gel 60 column chromatography (SG60CC) and high performance liquid chromatography (HPLC), and their chemical structure deduced by Nuclear Magnetic Resonance (NMR) analysis. ResultsThe DCM partitioned extract of SBP (DCMSBP) had an antityrosinase activity (IC50, 159.4 μg/mL) and was fractionated by SG60CC, providing five fractions (DCMSBP1–5). The DCMSBP5 fraction was the most active (IC50 = 18.8 μg/mL) and further fractionation by HPLC gave two active fractions, revealed by NMR analysis to be safflospermidine A and B. Interestingly, both safflospermidine A and B had a higher antityrosinase activity (IC50 of 13.8 and 31.8 μM, respectively) than kojic acid (IC50 of 44.0 μM). However, fraction DCMSBP5 had no significant antioxidation activity, while fractions DCMSBP1–4 showed a lower antioxidation activity than ascorbic acid. ConclusionSafflospermidine A and B are potential natural tyrosinase inhibitors.

Inhibitory Effect of Sesamolin on Melanogenesis in B16F10 Cells Determined by In Vitro and Molecular Docking Analyses.

Melanin protects the skin against the harmful effects of ultraviolet irradiation. However, melanin overproduction can result in several aesthetic problems, including melasma, freckles, age spots and chloasma. Therefore, development of anti-melanogenic agents is important for the prevention of serious hyperpigmentation diseases. Sesamolin is a lignan compound isolated from sesame seeds with several beneficial properties, including potential for melanin inhibition. The aim of this study was to evaluate the anti-melanogenic effect of sesamolin in cell culture in vitro and the underlying mechanism of inhibition using molecular docking simulation. Melanogenesis was induced by 3-isobutyl-1-methylxanthine in B16F10 melanoma cells, and the inhibitory effects of sesamolin were evaluated using zymography, a tyrosinase inhibitory activity assay, western blotting, and real-time reverse transcription-polymerase chain reaction analysis. Docking simulations between sesamolin and tyrosinase were performed using Autodock vina. Sesamolin significantly inhibited the expression of melanogenesis-related factors tyrosinase, and tyrosinase-related proteins 1 and 2 at the mRNA and protein levels. Treatment of melanoma cells with 50 µM sesamolin demonstrated the strongest inhibition against intercellular tyrosinase and melanin synthesis without exerting cytotoxic effects. Sesamolin significantly reduced mushroom tyrosinase activity in a dose-dependent manner via a competitive inhibition mechanism. Tyrosinase docking simulations supported that sesamolin (-6.5 kcal/mol) bound to the active site of tyrosinase more strongly than the positive control (arbutin, -5.7 kcal/mol). Sesamolin could be developed as a melanogenesis inhibiting agent owing to its dual function in blocking the generation of melanogenesis-related enzymes and inhibiting the enzymatic response of tyrosinase.

Anti-Melanogenic Effect of Chestnut Spike Extract through Downregulation of Tyrosinase-Related Proteins and Activation of ERK 1/2

Melanin has been reported to be the key factor for skin homeostasis. Besides defining an important human phenotypic trait, melanin overproduction may cause various disorders such as vitiligo, Addison's disease, Cushing's syndrome, and melasma. In this study, we aimed to investigate the anti-melanogenic potential of dried spike extract of chestnut. The extract inhibited tyrosinase (TYR) activity in a dose-dependent manner. Cellular melanin content decreased markedly after treatment with the extract. The spike extract inhibited microphthalmia-associated transcription factor (MITF) expression and downregulated TYR, TYRP-1, and TYRP-2 protein expression by increasing the phosphorylation of extracellular signal-regulated kinase (ERK)1/2 signalling pathway in melan-a cells. In addition, treatment with U0126, a specific inhibitor of ERK, restored melanin content. Collectively, these results suggest that the chestnut spike extract attenuated melanogenesis by inhibiting MITF expression and downregulating TYR, TYRP-1, and TYRP-2 protein expressions via activation of ERK1/2 pathway.

Ethyl acetate extract from Panax ginseng C.A. Meyer and its main constituents inhibit α-melanocyte-stimulating hormone-induced melanogenesis by suppressing oxidative stress in B16 mouse melanoma cells

Ethnopharmacological relevanceHyperpigmentation disease involves darkening of the skin color due to melanin overproduction. Panax ginseng C.A. Meyer is a well-known traditional Chinese medicine and has a long history of use as a skin lightener to inhibit melanin formation in China, Korea and some other Asian countries. However, the constituents and the molecular mechanisms by which they affect melanogenesis are not fully clear. Aim of the studyThe purpose of this study was to identify the active ingredient in Panax ginseng C.A. Meyer extract that inhibits mushroom tyrosinase activity and to investigate the antioxidative capacity and molecular mechanisms of the effective extract on melanogenesis in B16 mouse melanoma cells. Materials and methodsAqueous extracts of Panax ginseng C.A. Meyer were successively fractionated with an equal volume of chloroform, ethyl acetate, and n-butyl alcohol to determine the effects by examining the activity of mushroom tyrosinase. The effective fraction was analyzed using HPLC and LC-MS. The antioxidative capacity and the inhibitory effects on melanin content, cell intracellular tyrosinase activity, and melanogenesis protein levels were determined in α-melanocyte-stimulating hormone (α-MSH)-treated B16 mouse melanoma cells. ResultsThe ethyl acetate extract from Panax ginseng C.A. Meyer (PG-2) had the highest inhibiting effect on mushroom tyrosinase, mainly contained phenolic acids, including protocatechuic acid, vanillic acid, p-coumaric acid, salicylic acid, and caffeic acid, and exhibited apparent antioxidant activity in vitro. PG-2 and its main constituents significantly decreased melanin content, suppressed cellular tyrosinase activity, and reduced expression of tyrosinase protein to inhibit B16 cells melanogenesis induced by α-MSH, and no cytotoxic effects were observed. They also inhibited cellular reactive oxygen species (ROS) generation, increased superoxide dismutase (SOD) activity and glutathione (GSH) level in α-MSH-treated B16 cells effectively. And those activities of its main constituents could reach more than 80% of PG-2. The ROS scavengers N-acetyl-L-cysteine (NAC) had a similar inhibitory effect on melanogenesis. ConclusionsThese results suggest that ethyl acetate extract from Panax ginseng C.A. Meyer has the highest effect on inhibiting melanogenesis, and that its main components are polyphenolic compounds, which may inhibit melanogenesis by suppressing oxidative stress. This work provides new insight into the active constituents and molecular mechanisms underlying skin-lightening effect of Panax ginseng C.A. Meyer.

Increased therapeutic efficacy of a newly synthesized tyrosinase inhibitor by solid lipid nanoparticles in the topical treatment of hyperpigmentation.

Hyperpigmentation caused by melanin overproduction is a major skin disorder in humans. Inhibition of tyrosinase, a key regulator of melanin production, has been used as an effective strategy to treat hyperpigmentation. In this study, we investigated the use of solid lipid nanoparticles (SLNs) as a highly effective and nontoxic means to deliver a newly synthesized potent tyrosinase inhibitor, MHY498, and to target melanocytes through the skin. MHY498-loaded SLNs (MHY-SLNs) were prepared by an oil-in-water emulsion solvent-evaporation method, and their morphological and physicochemical properties were characterized. MHY-SLNs showed a prolonged drug-release profile and higher skin permeation than that of MHY solution. In an in vivo evaluation of antimelanogenic activity, MHY-SLNs showed a prominent inhibitory effect against ultraviolet B-induced melanogenesis, resulting in no change in the skin color of C57BL/6 mouse, compared with that observed in an MHY solution-treated group and an untreated control group. The antimelanogenic effect of MHY-SLNs was further confirmed through Fontana–Masson staining. Importantly, MHY-SLNs did not induce any toxic effects in the L929 cell line. Overall, these data indicate that MHY-SLNs show promise in the topical treatment of hyperpigmentation.