Tyrosinase mRNA Expression Research Articles

Antioxidant and Skin-Whitening Efficacy of a Novel Decapeptide (DP, KGYSSYICDK) Derived from Fish By-Products.

The skin is vulnerable to damage from ultraviolet rays and oxidative stress, which can lead to aging and pigmentation issues. This study investigates the antioxidant and whitening efficacy of a decapeptide (DP, KGYSSYICDK) derived from marine fish by-products and evaluates its potential as a new skin-whitening agent. DP demonstrated high antioxidant activity, showing comparable or superior performance to Vitamin C (Vit. C) in ferric reducing antioxidant power (FRAP) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assays. In hydrogen peroxide (H2O2)-treated HaCaT cells, DP increased cell viability and reduced reactive oxygen species (ROS) generation. Furthermore, DP inhibited tyrosinase activity and decreased melanin production in α-melanocyte stimulating hormone (α-MSH)-induced B16F10 melanoma cells in a dose-dependent manner. Reverse transcription polymerase chain reaction (RT-PCR) analysis revealed that DP reduces the mRNA expression of MITF, tyrosinase, and MC1R, thus suppressing melanin production. DP exhibits strong binding interactions with multiple amino acid residues of tyrosinase, indicating potent inhibitory effects on the enzyme. These results suggest that DP possesses significant antioxidant and whitening properties, highlighting its potential as a skin-whitening agent. Future research should focus on optimizing DP's structure and exploring structure-activity relationships.

The Antioxidant and Whitening Effect of Miracle Fruit (Synsepalum dulcificum) Seed and Leaf Methanol Extracts

The seed and leaf 70% methanol extracts of miracle fruit (Synsepalum dulcificum) were investigated for its whitening activity for application as a functional ingredient in cosmetic products. At the leaf extract concentration of 100 mg/ml, the DPPH radical scavenging activity was found to be 94.58%, the ABTS+ radical scavenging activity was 36.62%. The total polyphenolic content of seed and leaf extract was 18.76 mgGAE/g, 71.42 mgGAE/g, respectively. The seed and leaf extracts reduced both tyrosinase activity and L-DOPA oxidation in a concentration-dependent manner. In B16F10 mouse melanoma cells, leaf extract inhibited 30% of melanin synthesis at 100 mg/ml. Miracle fruit seed and leaf extracts also inhibited the expression of melanogenesis genes such as microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein (TRP)-1. Moreover, reverse transcription-polymerase chain reaction of the extract showed that the mRNA expression of MITF, tyrosinase, and TRP-1 was decreased. The data suggested a protective role for the Synsepalum dulcificum seed and leaf extracts against melanogenesis.

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.

Kaempferol promotes melanogenesis and reduces oxidative stress in PIG1 normal human skin melanocytes

Vitiligo is an autoimmune disease characterized by depigmentation. Kaempferol is a flavonoid compound with broad anti-inflammatory and antioxidant properties. The purpose of this study was to investigate the effect of kaempferol on melanogenesis in PIG1 normal human skin melanocytes and its response to oxidative stress. The effect of kaempferol on melanin synthesis in PIG1 normal human skin melanocytes was explored by measuring tyrosinase activity, melanin content, mRNA and protein expression of key enzymes and expression of related pathway proteins. The effects of kaempferol pretreatment on cell viability, apoptosis, ROS level and HO-1 protein level under H2 O2 stimulation were explored. When treated with kaempferol, the tyrosinase activity and melanin content of PIG1 cells increased, the mRNA and protein expressions of TYR, TRP1, TRP2 and MITF increased, and the phosphorylation level of ERK1/2 increased. Upon the stimulation of H2 O2 , kaempferol reduced the production of ROS, decreased apoptosis and increased the protein expression of HO-1 in PIG1 cells. In addition, kaempferol inhibited oxidative stress-induced melanin reduction and promoted melanin synthesis in PIG1 cells and protected against H2 O2 -induced oxidative stress damage.

Aktivitas pegagan (Centella asiatica) pada dermatologi

Pegagan (Centella asiatica L.) is a herbal plant used in dermatology that has activity in treating skin diseases and skin lesions such as excoriations, burns, hypertrophic scars, antioxidants, anti-aging, skin whitening, and as a cosmetic ingredient. This review aims to collect data regarding the activity of Centella asiatica herb extracts in dermatology in both preclinical and clinical trial identification is done by searching literature through media Science Direct and Google Scholar using the keywords ''Centella asiatica'', ''Gotu kola'', ''dermatology'', ''cosmetics'', and ''whitening''. The search was based on the inclusion and exclusion criteria that had been set. The literature results show that the chemical constituents of Centella asiatica, such as asiaticoside, madecassoside, asiatic acid, and madecassic acid, are phytochemicals that play an essential role in the pharmacological activity of Centella asiatica in dermatology as a treatment and skin care. In both preclinical and clinical tests, it was shown that administration of Centella asiatica was capable of proliferating fibroblasts, activating the Smads pathway, increasing collagen synthesis, reducing metalloproteinase activity by increasing collagen deposition, and reducing melanin content in melanocytes so that it can modulate melanogenesis by inhibiting the expression of tyrosinase mRNA.

Hibiscus Flower Extract and Niacinamide Show Enhanced Whitening Effects in Mouse Melanoma Cells (B16F10)

Melanoma, a type of cancer that most often occurs on skin exposed to UV rays, is becoming increasingly common. Recent research has focused actively on using natural products. The goal of this study was to compare the melanin-inhibitory effects of Hibiscus (Hibiscus sabdariffa L.) flower Extract (HE) and Niacinamide (NA), a functional ingredient with whitening effects, on melanoma cells. The 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the effects of HE (1, 3.5, 7, 10, and 14 μg/mL) and NA (1, 5, 10, 20, and 25 μg/mL) on cell viability. A lactate dehydrogenase cytotoxicity assay was employed to confirm the cytotoxic effect of HE and NA on mouse melanoma cells. The real-time reverse-transcription polymerase chain reaction was performed to analyze Tyrosinase (TYR), Tyrosinase-Related Protein (TRP), and Microphthalmia-associated Transcription Factor (MITF) mRNA expression levels to determine whitening effects. Vitamin C (VC, 10 µg/mL) was selected as a control. The MTT assay showed that HE and NA were non-cytotoxic at <10 μg/mL in B16F10 cells when compared to the control, VC. The cytotoxicity of HE was confirmed to be lower than the control (VC) when a concentration of 7 µg/mL or lower was applied. The cytotoxicity of NA was low even at a concentration of 10 µg/mL. HE showed greater whitening effects at lower concentrations (i.e., 1 µg/mL) than VC (10 µg/mL). HE had almost no cytotoxicity compared to NA and VC, and the expression levels of whitening inhibition genes MITF and TYR were higher than VC, indicating that it can be used as a healthy functional food or cosmetic material.

Enhanced Anti-Skin Aging Effects of Fermented Black Ginseng (Panax ginseng C.A. Meyer) by Aspergillus niger KHNT-1

Functional foods to prevent aging, particularly skin aging, have grown in popularity as society ages and science uncovers the pathological mechanisms of aging. In this study, we used processed ginseng, one of the famous functional foods, along with fermentation utilizing the novel Aspergillus niger strain KHNT-1 to enhance its value and efficacy. We successfully produced fermented black ginseng (FBG) and investigated its anti-skin aging properties, such as anti-melanogenic, anti-wrinkle, and antioxidant activities. The results showed that FBG at 100 μg/mL inhibited tyrosinase and melanin production in IBMX-stimulated B16F10 cells. FBG significantly reduced tyrosinase, TYRP-1, and MITF mRNA expression. Moreover, FBG stimulated anti-wrinkle effects in UVB-irradiated human dermal fibroblast (FBG) cells by inhibiting elastase activity, and decreasing MMP-1 and MMP-9 while increasing COL-1 mRNA expression. Furthermore, FBG showed antioxidant activity by reducing ROS levels in H2O2-induced HaCat cells. All tests showed that FBG had better anti-melanogenic, anti-wrinkle, and antioxidant activities than black ginseng (BG) and white ginseng (WG). Interestingly, FBG had lower toxicity in B16F10, HDF, and HaCat cells compared with BG. Thus, this study discovers the underlying mechanism of FBG as a functional material with anti-skin-aging properties.

Molecular Analysis of the Melanogenesis Inhibitory Effect of Saponins-Rich Fraction of Argania spinosa Leaves Extract.

Plant saponins are abundant and diverse natural products with a great potential for use in drug-discovery research. Here, we evaluated extracts of saponins-rich fractions of argan leaves and argan oil extraction byproducts (shell, pulp, press cake) for their effect on melanogenesis. Results show that from among the samples tested, only the saponins-rich fraction from leaves (ALS) inhibited melanin production in B16 murine melanoma (B16) cells. The mechanism of the melanogenesis inhibition was elucidated by determining the protein and mRNA expression of melanogenesis-associated enzymes tyrosinase (TYR), tyrosinase-related protein 1 (TRP1), and dopachrome tautomerase (DCT), and microphthalmia-associated transcription factor (MITF), and performing DNA microarray analysis. Results showed that 10 µg/mL ALS significantly inhibited melanogenesis in B16 cells and human epidermal melanocytes by 59% and 48%, respectively, without cytotoxicity. The effect of ALS on melanogenesis can be attributed to the decrease in TYR, TRP1, and MITF expression at the protein and mRNA levels. MITF inhibition naturally led to the downregulation of the expression of Tyr and Trp1 genes. Results of the DNA microarray analysis revealed the effect on melanogenesis-associated cAMP and Wnt signaling pathways’ genes. The results of this study suggest that ALS may be used in cosmeceuticals preparations for hyperpigmentation treatment.

Extraction and Concentration of Waste Pueraria lobata Stems with Antioxidants and Anti-Melanogenesis Activity as a Novel Skin Whitening Agent for Natural Cosmetic Prototypes.

The root of Pueraria lobata (Willd.) is used commercially in different products, including dietary supplements, cosmetics, and teas, but its stem part is rarely used and studied. Therefore, this study evaluated the antioxidant and anti-melanogenesis activities of the bioactive fraction of P. lobata stem and investigated whether the activated carbon decolorization technique would have an impact on its activity and chemical composition. We observed that the dichloromethane fraction of P. lobata stem (DCM-PLS) has excellent antioxidant and anti-melanin synthesis activity at a concentration of 50 μg/mL. For the investigation of the anti-melanogenesis mechanism, we evaluated the mRNA expression of tyrosinase, which was depressed by the DCM-PLS. Daidzin was identified as the main active ingredient in DCM-PLS by using a high-performance liquid chromatography-diode array detector-hyphenated with tandem mass spectrometry. In addition, the activated carbon decolorization technology has no negative impact on the main components and bioactivity of DCM-PLS. DCM-PLS also did not induce any skin response in the human skin safety test. Collectively, DCM-PLS could be used as a natural type of skin-whitening agent in skin care products.

Lactobacillus Kimchicus-fermented Ficus caria fruits and leaves extract as an inhibitor of α-MSH-mediated melanogenesis in B16F10 mouse melanoma cells

Purpose: To explore the anti-melanogenetic effects of Lactobacillus Kimchicus-fermented Ficus caria fruits and leaves extracts (KFFE) in B16F10 mouse melanoma cells.Methods: The anti-melanogenetic effects of Lactobacillus Kimchicus-fermented Ficus caria fruit and leaf extracts (KFFE) were assessed using melanin contents assay and tyrosinase expression and activity assay in α-MSH-treated B16F10 mouse melanoma cells.Results: The KFFE reduced α-MSH-mediated melanin synthesis in B16F10 mouse melanoma cells, while the tyrosinase mRNA expression was down-regulated by KFFE in B16F10 mouse melanoma cells (p &lt; 0.05). Furthermore, cellular tyrosinase activity was downregulated by KFFE in B16F10 mouse melanoma cells (p &lt; 0.05).Conclusion: KFFE functions to repress melanin synthesis and thus, can potentially be used as a cosmetic ingredient.

Cypress tree (Chamaecyparis obtusa) Bark extract inhibits melanogenesis through repressing CREB and MITF signalling pathways in α-MSH-stimulated B16F10 cells

ABSTRACT Cypress tree (Chamaecyparis obtusa) bark is well-known for its bio-functional activities and high content of polyphenol and flavonoids. It has previously exhibited antioxidant, anti-pathogenic, and anti-inflammatory activities. Our study aimed to investigate the anti-melanogenic effect of Cypress Tree Bark extract (CBE). We evaluated cellular tyrosinase activity and melanin content in alpha-melanocyte-stimulating hormone (α-MSH) induced B16F10 murine melanoma cells. We analyzed microphthalmia-associated transcription factor (MITF), tyrosinase-related protein (TRP1 and TRP2), and cAMP response element-binding protein (CREB) activation via phosphorylation of AKT and ERK using western blot analysis. Tyrosinase, MITF, TRP1, and TRP2 mRNA expression were examined via real-time polymerase chain reaction. CBE restored melanin content and tyrosinase activity remarkably in α-MSH stimulated melanoma cells. It exhibited an anti-melanogenic effect through suppressing MITF, TRP1, TRP2, tyrosinase mRNA and protein expression in α-MSH-induced B16F10 cells. Furthermore, CBE has significantly inhibited CREB activation by suppressing AKT and extracellular signal-regulated kinase phosphorylation. Our data strongly suggest that CBE has potential effects against melanogenesis.

Deoxyvasicinone with Anti-Melanogenic Activity from Marine-Derived Streptomyces sp. CNQ-617.

The tricyclic quinazoline alkaloid deoxyvasicinone (DOV, 1) was isolated from a marine-derived Streptomyces sp. CNQ-617, and its anti-melanogenic effects were investigated. Deoxyvasicinone was shown to decrease the melanin content of B16F10 and MNT-1 cells that have been stimulated by α-melanocyte-stimulating hormone (α-MSH). In addition, microscopic images of the cells showed that deoxyvasicinone attenuated melanocyte activation. Although, deoxyvasicinone did not directly inhibit tyrosinase (TYR) enzymatic activity, real-time PCR showed that it inhibited the mRNA expression of TYR, tyrosinase-related protein 1 (TRP-1), and tyrosinase-related protein 2 (TRP-2). In the artificial 3D pigmented skin model MelanodermTM, deoxyvasicinone brightened the skin significantly, as confirmed by histological examination. In conclusion, this study demonstrated that the marine microbial natural product deoxyvascinone has an anti-melanogenic effect through downregulation of melanogenic enzymes.

Whitening and Moisturizing Effects of Hydrolyzed Swiftlet Nest Extracts

Purpose: This research verified the skin whitening and moisturizing effects of hydrolyzed swiftlet nest extracts (HSNE) in vitro using human keratinocytes and melanoma.Methods: To confirm the antioxidant effect of HSNE, DPPH radical-scavenging activity was measured. To find out the whitening effect of HSNE, the genes related to melanogenesis, mRNA expression of tyrosinase (TYR), tyrosinase related protein (TRP) 1, 2 and microphthalmia associated transcription factor (MITF) were measured. We also measured the melanin contents after treatment of HSNE to confirm the anti-melanogenesis effect. Using reverse transcription polymerase chain reaction (RT-PCR), the genes related to moisturizing such as aquaporin (AQP) 3, hyaluronan synthase (HAS) 1, 2, and 3 were determined. The results of the tests were analyzed with student’s t-test and expressed as mean±standard deviation.Results: DPPH radical scavenging effects of HSNE increased in a concentration dependent manner. The expression of melanogenesis-related genes were inhibited by the treatment of HSNE in a concentration-dependent manner (MITF, TYR, TRP1, and 2). Melanin contents also decreased with the treatment of HSNE. The expression of moisturizing-related genes (HAS1, 2, 3, and AQP3) increased in a concentration-dependent manner.Conclusion: It is confirmed that the hydrolyzed swiftlet nest extracts have skin whitening and moisturizing effects and can be used as a functional cosmetic raw material.

Di (Isoquinolin-1-Yl) Sulfane (DIQS) Inhibits Melaninogenesis by Modulating PKA/CREB and MAPK Signaling Pathways

The novel synthetic compound Di (isoquinolin-1-yl) sulfane (DIQS) was identified by zebrafish larva screening during the development of an agent to inhibit abnormal hyperpigmentation. In this study, we investigated the inhibitory effect of DIQS on melanogenesis and its underlying mechanism. DIQS inhibited melanin production and tyrosinase activity in B16F10 cells stimulated with α-melanocyte-stimulating hormone (α-MSH), as well as zebrafish embryos and reconstituted human skin tissue containing melanocytes. DIQS decreased the mRNA and protein expression of microphthalmia-associated transcription factor (MITF) and tyrosinase at a concentration of 10 μM. DIQS also inhibited the phosphorylation of cAMP response element-binding protein (CREB) and p-p38 and p-JNK stimulated by α-MSH. These results suggest that DIQS attenuates hyperpigmentation via inhibition of the cAMP/PKA/CREB/MITF/tyrosinase axis and MAPK pathways. Liquid chromatography–tandem mass spectrometry analysis revealed that DIQS blocked the conversion of tyrosine to L-3,4-dihydroxyphenylalanine (L-DOPA) in zebrafish embryos. Finally, we confirmed that DIQS was non-toxic in reconstituted human tissues such as the epidermis, used to test skin sensitization, and the cornea, used to test eye irritation. In summary, the results of this study suggest the potential of DIQS as a small-molecule agent for skin-whitening cosmetics and the treatment of hyperpigmentation disorders without biological toxicity.

Oxidative stress in the skin: Impact and related protection.

Skin, our first interface to the external environment, is subjected to oxidative stress caused by a variety of factors such as solar ultraviolet, infrared and visible light, environmental pollution, including ozone and particulate matters, and psychological stress. Excessive reactive species, including reactive oxygen species and reactive nitrogen species, exacerbate skin pigmentation and aging, which further lead to skin tone unevenness, pigmentary disorder, skin roughness and wrinkles. Besides these, skin microbiota are also a very important factor ensuring the proper functions of skin. While environmental factors such as UV and pollutants impact skin microbiota compositions, skin dysbiosis results in various skin conditions. In this review, we summarize the generation of oxidative stress from exogenous and endogenous sources. We further introduce current knowledge on the possible roles of oxidative stress in skin pigmentation and aging, specifically with emphasis on oxidative stress and skin pigmentation. Meanwhile, we summarize the science and rationale of using three well-known antioxidants, namely vitamin C, resveratrol and ferulic acid, in the treatment of hyperpigmentation. Finally, we discuss the strategy for preventing oxidative stress-induced skin pigmentation and aging.

Evaluation of Anti-Melanogenesis Activity of Enriched Pueraria lobata Stem Extracts and Characterization of Its Phytochemical Components Using HPLC-PDA-ESI-MS/MS.

The root of Pueraria lobata (Willd.) is a widely used herbal medicine worldwide, whereas the stem of the plant is discarded or used as feed for livestock. To reuse and exploit the stem of P. lobata as a resource, we investigated its potential as a skin-whitening agent. We found that the developed, enriched P. lobata stem (PLS) extract significantly inhibited melanin production in the 3-isobutyl-1-methylxanthine-induced B16/F10 cells at a concentration of 50 μg/mL. To further confirm the mechanism of the antimelanogenic effect of the enriched PLS extracts, we examined the mRNA expression of tyrosinase, which was suppressed by the extracts. To standardize and implement effective quality control of the enriched PLS extracts, its major chemical constituents were identified by high-performance liquid chromatography–photodiode array–electrospray ionization–mass spectrometry. In total, 12 constituents were identified. In silico analysis showed that the main constituents, puerarin and daidzin, had excellent binding affinities for human tyrosinase. Collectively, our results suggest that the PLS extracts could be used as anti-pigmentation agents.

Antimelanogenesis Effects of Theasinensin A.

Theasinensin A (TSA) is a major group of catechin dimers mainly found in oolong tea and black tea. This compound is also manufactured with epigallocatechin gallate (EGCG) as a substrate and is refined after the enzyme reaction. In previous studies, TSA has been reported to be effective against inflammation. However, the effect of these substances on skin melanin formation remains unknown. In this study, we unraveled the role of TSA in melanogenesis using mouse melanoma B16F10 cells and normal human epidermal melanocytes (NHEMs) through reverse transcription polymerase chain reaction (RT-PCR), Western blotting analysis, luciferase reporter assay, and enzyme-linked immunosorbent assay analysis. TSA inhibited melanin formation and secretion in α-melanocyte stimulating hormone (α-MSH)-induced B16F10 cells and NHEMs. TSA down-regulated the mRNA expression of tyrosinase (Tyr), tyrosinase-related protein 1 (Tyrp1), and Tyrp2, which are all related to melanin formation in these cells. TSA was able to suppress the activities of certain proteins in the melanocortin 1 receptor (MC1R) signaling pathway associated with melanin synthesis in B16F10 cells: cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB), protein kinase A (PKA), tyrosinase, and microphthalmia-associated transcription factor (MITF). We also confirmed α-MSH-mediated CREB activities through a luciferase reporter assay, and that the quantities of cAMP were reduced by TSA in the enzyme linked immunosorbent assay (ELISA) results. Based on these findings, TSA should be considered an effective inhibitor of hyperpigmentation.

Expression of tyrosine pathway enzymes in mice demonstrates that homogentisate 1,2-dioxygenase deficiency in the liver is responsible for homogentisic acid-derived ochronotic pigmentation.

Alkaptonuria (AKU) is caused by homogentisate 1,2‐dioxygenase (HGD) deficiency. This study aimed to determine if HGD and other enzymes related to tyrosine metabolism are associated with the location of ochronotic pigment. Liver, kidney, skin, bone, brain, eyes, spleen, intestine, lung, heart, cartilage, and muscle were harvested from 6 AKU BALB/c Hgd −/− (3 females, 3 males) and 4 male C57BL/6 wild type (WT) mice. Hgd, 4‐hydroxyphenylpyruvate dioxygenase (4‐Hppd), tyrosine hydroxylase (Th), and tyrosinase (Tyr) mRNA expression was investigated using qPCR. Adrenal gland and gonads from AKU Hgd tm1a −/− mice were LacZ stained, followed by qPCR analysis of Hgd mRNA. The liver had the highest expression of Hgd, followed by the kidney, with none detected in cartilage or brain. Low‐level Hgd expression was observed within developing male germ cells within the testis and epididymis in Hgd tm1a −/−. 4‐Hppd was most abundant in liver, with smaller amounts in kidney and low‐level expression in other tissues. Th was expressed mainly in brain and Tyr was found primarily in the eyes. The tissue distribution of both Hgd and 4‐Hppd suggest that ochronotic pigment in AKU mice is a consequence of enzymes within the liver, and not from enzymatic activity within ochronotic tissues. Excessive accumulation of HGA as ochronotic pigment in joints and other connective tissues originates from the circulation and therefore the extracellular fluid. The tissue distribution of both Th and Tyr suggests that these enzymes are not involved in the formation of HGA‐derived ochronotic pigment.

Effects of Captopril on Melanin Formation in B16 cells

The effect of captopril on melanin formation in B16 cells was investigated. In B16 intracellular model system, the effect of captopril on antityrosinase activity was found dose-dependent and correlated to its ability to suppress melanin formation. The copper chelation by captopril may in part be responsible for the inhibition of tyrosinase activity. Captopril also displayed a remarkable reducing ability and significantly inhibited ROS generation. Interestingly, captopril also significantly suppressed tyrosinase mRNA expression, as determined by reverse transcription-polymerase chain reaction (RT-PCR). Overall, the results showed that the protective effect of captopril makes it a potent inhibitor of melanin formation.

Melochia corchorifolia extract inhibits melanogenesis in B16F10 mouse melanoma cells via activation of the ERK signaling.

Numerous researches have focused on discovering available inhibitors of melanogenesis from natural medicinal plants with stable efficacy and safety to resolve cutaneous hyperpigmentary problems. Melochia corchorifolia Linn. (MC) has been used as folk medicine to treat various diseases. However, the effect of MC on melanogenesis remains unknown. In this study, we investigated the effect of MC extract on melanogenesis and its underlying mechanisms in B16F10 mouse melanoma cells. B16F10 cells were treated with MC extract, and then, cell viability, melanin content, and tyrosinase activity were analyzed. The mRNA and protein expression of tyrosinase and microphthalmia-associated transcription factor (MITF) were evaluated using real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting, respectively. Phosphorylated or total protein levels in MC extract-induced signaling pathways were analyzed by Western blotting. Treatment of B16F10 cells with MC extract inhibited melanin synthesis and intracellular tyrosinase activity in a dose-dependent manner with no cytotoxicity. Protein and mRNA expressions of tyrosinase and MITF were also significantly decreased by MC extract treatment. In addition, phosphorylated level of extracellular signal-regulated kinase (ERK) was obviously increased by MC extract, but AKT pathway was not activated. Inhibited ERK phosphorylation by pretreatment with a selective ERK inhibitor PD98059 significantly reversed the decreased melanin content induced by treatment with MC extract in B16F10 cells. MC extract inhibits melanogenesis in B16F10 mouse melanoma cells through suppression of MITF-tyrosinase signaling pathway by ERK activation.