In Vitro In Silico Screening Strategy and Mechanism of Novel Tyrosinase Inhibitory Peptides from Nacre of Hyriopsis cumingii.

For thousands of years, pearl and nacre powders have been important traditional Chinese medicines known for their skin whitening effects. To prepare the enzymatic hydrolysates of Hyriopsis cumingii nacre powder (NP-HCH), complex enzymatic hydrolysis by pineapple protease and of neutral protease was carried out after the powder was pre-treated with a high-temperature and high-pressure method. The peptides were identified using LC-MS/MS and picked out through molecular docking and molecular dynamics simulations. Subsequently, the tyrosinase inhibitory and antioxidant properties of novel tyrosinase inhibitory peptides were investigated in vitro. In addition, the enzymatic activity of tyrosinase in B16F10 cells as well as melanin content and antioxidant enzyme levels were also examined. The results showed that a tyosinase inhibitory peptide (Tyr-Pro-Asn-Pro-Tyr, YPNPY) with an efficient IC50 value of 0.545 ± 0.028 mM was identified. The in vitro interaction results showed that YPNPY is a reversible competitive inhibitor of tyrosinase, suggesting that it binds to the free enzyme. The B16F10 cell whitening test revealed that YPNPY can reduce the melanin content of B16F10 cells by directly inhibiting the activity of intracellular tyrosinase. Additionally, it indirectly affects melanin production by acting as an antioxidant. These results suggest that YPNPY could be widely used as a tyrosinase inhibitor in whitening foods and drugs.

Comoclathrin, a novel potent skin-whitening agent produced by endophytic Comoclathris strains associated with Andalusia desert plants.

As part of our screening program for the discovery of molecules of microbial origin with skin-whitening activity, 142 diverse fungal endophytes from a wide variety of Andalusia arid plants were screened, applying the OSMAC approach. The fungal strains CF-090361 and CF-090766, isolated from xerophytic plants, were selected as the most promising, while phylogenetic analysis revealed that both strains could represent a new species within the genus Comoclathris. The effect of different fermentation conditions on the production of tyrosinase inhibitory activity was examined, in order to identify the optimum cultivation conditions. LCMS based metabolomics was applied to determine significant differences between the strains and fermentation conditions, and to identify potential bioactive secondary metabolites. Bioassay-guided purification of the main active components led to the isolation of three new compounds (1-3), along with the known compounds graphostrin B (4) and brevianamide M (5). Compound 1 (Comoclathrin) demonstrated the strongest anti-tyrosinase activity (IC50 0.16 µΜ), which was 90-times higher than kojic acid (IC50 14.07 µΜ) used as positive control. Additionally, comoclathrin showed no significant cytotoxicity against a panel of cancer cell lines (HepG2, A2058, A549, MCF-7 and MIA PaCa-2) and normal BJ fibroblasts. These properties render comoclathrin an excellent development candidate as whitening agent.

Skin-whitening mechanism of cumin (Cuminum cyminum L.) extract.

Skin-whitening effect is closely linked with the melanogenesis inhibitory activity and free radical scavenging capacity. The purpose of the present study was to evaluate the skin-whitening effect of cumin (Cuminum cyminum L.) extract. The whitening activity was evaluated by cell-free mushroom tyrosinase assay, free radical scavenging assay, cell viability assay, cellular tyrosinase assay and melanin content assay using B16F10 murine melanoma cells. The results showed that cumin extract exhibited concentration-dependent inhibitory effect on both monophenolase and diphenolase activities of mushroom tyrosinase (IC50 values of 1.027mg/mL and 0.977mg/mL, respectively). Kinetic study on diphenolase showed that the cumin extract was a reversible mixed-type inhibitor, and the inhibition constant (KI) was determined to be 0.62mg/mL. In addition, cumin extract significantly suppressed melanin production and cellular tyrosinase activity of B16F10 melanoma cells in a concentration and time dependent manner without cytotoxicity. Moreover, cumin extract exerted strong scavenging capacity on DPPH, hydroxyl and superoxide anion radicals. Taken together, these results strongly suggest that cumin is a potential skin-whitening agent for the cosmetic industry.

Skin-Whitening and Anti-Wrinkle Effects of Bioactive Compounds Isolated from Peanut Shell Using Ultrasound-Assisted Extraction.

Response surface methodology was employed to optimize the ultrasound-assisted extraction (UAE) conditions for simultaneous optimization of dependent variables, including DPPH radical scavenging activity (RSA), tyrosinase activity inhibition (TAI), and collagenase activity inhibition (CAI) of peanut shell extracts. The effects of the main variables including extraction time (5.0~55.0 min, X1), extraction temperature (26.0~94.0 °C, X2), and ethanol concentration (0.0%~99.5%, X3) were optimized. Based on experimental values from each condition, quadratic regression models were derived for the prediction of optimum conditions. The coefficient of determination (R2) of the independent variable was in the range of 0.89~0.96, which demonstrates that the regression model is suitable for the prediction. In predicting optimal UAE conditions based on the superimposing method, extraction time of 31.2 min, extraction temperature of 36.6 °C, and ethanol concentration of 93.2% were identified. Under these conditions, RSA of 74.9%, TAI of 50.6%, and CAI of 86.8% were predicted, showing good agreement with the experimental values. A reverse transcription polymerase chain reaction showed that peanut shell extract decreased mRNA levels of tyrosinase-related protein-1 and matrix metalloproteinase-3 genes in B16-F0 cell. Therefore, we identified the skin-whitening and anti-wrinkle effects of peanut shell extracts at protein as well as gene expression levels, and the results show that peanut shell is an effective cosmetic material for skin-whitening and anti-wrinkle effects. Based on this study, peanut shell, which was considered a byproduct, can be used for the development of healthy foods, medicines, and cosmetics.

Ishophloroglucin A Isolated from Ishige okamurae Suppresses Melanogenesis Induced by α-MSH: In Vitro and In Vivo.

Diphlorethohydroxycarmalol (DPHC) isolated from Ishige okamurae (IO) showed potential whitening effects against UV-B radiation. However, the components of IO as well as their molecular mechanism against α-melanocyte-stimulating hormone (α-MSH) have not yet been investigated. Thus, this study aimed to investigate the inhibitory effects of Ishophloroglucin A (IPA), a phlorotannin isolated from brown algae IO, and its crude extract (IOE), in melanogenesis in vivo in an α-MSH-induced zebrafish model and in B16F10 melanoma cells in vitro. Molecular docking studies of the phlorotannins were carried out to determine their inhibitory effects and to elucidate their mode of interaction with tyrosinase, a glycoprotein related to melanogenesis. In addition, morphological changes and melanin content decreased in the α-MSH-induced zebrafish model after IPA and IOE treatment. Furthermore, Western blotting results revealed that IPA upregulated the extracellular related protein expression in α-MSH-stimulated B16F10 cells. Hence, these results suggest that IPA isolated from IOE has a potential for use in the pharmaceutical and cosmetic industries.

Algae Metabolites in Cosmeceutical: An Overview of Current Applications and Challenges.

Cosmetics are widely used by people around the world to protect the skin from external stimuli. Consumer preference towards natural cosmetic products has increased as the synthetic cosmetic products caused adverse side effects and resulted in low absorption rate due to the chemicals' larger molecular size. The cosmetic industry uses the term "cosmeceutical", referring to a cosmetic product that is claimed to have medicinal or drug-like benefits. Marine algae have gained tremendous attention in cosmeceuticals. They are one of the richest marine resources considered safe and possessed negligible cytotoxicity effects on humans. Marine algae are rich in bioactive substances that have shown to exhibit strong benefits to the skin, particularly in overcoming rashes, pigmentation, aging, and cancer. The current review provides a detailed survey of the literature on cosmeceutical potentials and applications of algae as skin whitening, anti-aging, anticancer, antioxidant, anti-inflammation, and antimicrobial agents. The biological functions of algae and the underlying mechanisms of all these activities are included in this review. In addition, the challenges of using algae in cosmeceutical applications, such as the effectiveness of different extraction methods and processing, quality assurance, and regulations concerning extracts of algae in this sector were also discussed.

Ganoderma lucidum polysaccharide reduces melanogenesis by inhibiting the paracrine effects of keratinocytes and fibroblasts via IL-6/STAT3/FGF2 pathway.

Our previous study found that Ganoderma lucidum polysaccharide (GLP), bioactive ingredients from Ganoderma lucidum, protected fibroblasts from photoaging. However, whether GLP can affect melanogenesis in melanocytes through regulating paracrine mediators that secreted by keratinocytes and fibroblasts is unclear. We aimed to investigate the efficacy and mechanisms of action of GLP in melanogenesis by regulating paracrine effects of keratinocytes and fibroblasts. The effect of GLP on cell viability affected by GLP was measured by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. After an immortal keratinocyte line (HaCaT) and primary fibroblasts (FB) were treated with GLP, the supernatants of HaCaT and FB cells were collected and cocultured with an immortalized melanocyte line (PIG1). The expression levels of melanogenesis-associated genes in PIG1 cells were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analysis. Furthermore, FRS-2, ERK, JNK, and p38 phosphorylation levels were measured. Then, major melanogenic paracrine mediators in HaCaT and FB cells treated with GLP were evaluated by qRT-PCR and enzyme-linked immunosorbent assay (ELISA). In addition, the expression of IL-6 and STAT3 was examined in HaCaT and FB cells. GLP was not cytotoxic to HaCaT and FB cells. The supernatants of GLP-treated HaCaT and FB cells downregulated the expression levels of MITF, TYR, TYRP1, TYRP2, RAB27A, and FSCN1 genes and inhibited the phosphorylation of FRS-2, ERK, JNK, and p38 in PIG1 cells. GLP also decreased FGF2 secretion in HaCaT and FB cells. Moreover, GLP reduced IL-6 expression and STAT3 phosphorylation in HaCaT and FB cells. GLP reduced melanogenesis in melanocytes by inhibiting the paracrine effects of keratinocytes and fibroblasts via IL-6/STAT3/FGF2 pathway.

Ganoderma lucidum polysaccharide inhibits UVB-induced melanogenesis by antagonizing cAMP/PKA and ROS/MAPK signaling pathways.

Ultraviolet (UV)-induced pigmentation is very common in clinical practice, but the current treatments are rarely effective, accompanied by some side effects. Ganoderma lucidum polysaccharide (GLP) is a natural antioxidant with no toxic side effects, which can antagonize UVB-induced fibroblast photo aging. The study aims to explore the role of GLP in inhibiting UVB-induced melanogenesis and its possible mechanism. The expression of melanogenesis genes such as microphthalmia-associated transcription factor (MITF), tyrosine (TYR), tyrosinase related protein 1 (TYRP1), tyrosinase related protein 2 (TYRP2), ras-related protein Rab-27A (Rab27A), and Myosin shows an upward trend after exposure of B16F10 and PIG1 cells to UVB irradiation, but GLP can downregulate the expression of genes related to UVB-induced melanogenesis. GLP can inhibit UVB-activated protein kinase A (PKA) and mitogen-activated protein kinase (MAPK) signaling pathways. Besides, GLP protects mitochondria from UVB damage and inhibits reactive oxygen species (ROS) production. Also, UVB-induced cyclic adenosine monophosphate (cAMP) can be inhibited. It has been found in the experiments of UVB-induced skin pigmentation in zebrafish that GLP is capable of inhibiting UVB-induced skin pigmentation. Meanwhile, it can greatly relieve erythema reaction in guinea pig skin caused by high-dosage UVB irradiation. In conclusion, this study shows that GLP can inhibit UVB-induced melanogenesis by antagonizing cAMP/PKA and ROS/MAPK signaling pathways and is a potential natural safe whitening sunscreen additive.

Optimization of Antioxidant and Skin-Whitening Compounds Extraction Condition from Tenebrio molitor Larvae (Mealworm).

Skin-whitening ingredients are a very important part of the development of functional cosmetics and a wide variety of raw materials are used. Tyrosinase is a key enzyme in the animal melanogenic pathway that is the rate-limiting step for the production of melanin. Several synthetic and naturally occurring tyrosinase inhibitors have been studied for skin-whitening. The development of natural agents is becoming more important due to the disadvantages of synthetics such as high cytotoxicity, insufficient penetration power, and low activity. The purpose of this study was to evaluate the total phenol content (TPC), antioxidant, and tyrosinase inhibition activity of mealworm (Tenebrio molitor larvae) extract, and the subsequent optimization of the extraction condition using statistically-based optimization. The major extraction variables extraction temperature, time, and ethanol concentration were optimized using response surface methodology (RSM). The results showed that optimum extraction temperature of 88.1 °C, extraction time of 43.7 min, and ethanol concentration of 72.0 v/v%, provided the predicted maximum levels of total phenolic compounds (TPC) of 5.41 mg GAE/g dry weight (DW) and tyrosinase inhibition activity (TIA) of 82.4%. From the validation experiment, 5.61 ± 0.2 mg GAE/g dry weight (DW), tyrosinase inhibition of 79.6 ± 3.3%, and radical scavenging activity of 91.8 ± 5.1 µg/mL were found and showed to be very similar to the predicted values. These results suggest that mealworm has great potential as a source of bioactive compounds which could be used as cosmetics, food, and pharmaceutical agents.

Poria cocos Wolf extracts represses pigmentation in vitro and in vivo.

In skin, melanocytes determine skin color using melanogenesis, which induces protective mechanism to oxidative stress and UV damage. However, when melanin is excessive produced by the various stimulus, the accumulated melanin induces hyperpigmentation disease such as melasma, freckles, Melanism ware induced. Therefore, it is implicated to finding potential agents for whitening to be used in cosmetic products. In our present study, we show that Poria cocos Wolf extracts decreased melanin synthesis in B16F10. And then this inhibition of melanogenesis was provoked by regulation of tyrosinase activity and tyrosinase and MITF expression. Moreover, Poria cocos Wolf extracts contained cream improved skin tone using increase of bright value. Overall, these results provide evidence to potential agent for whitening to be used in cosmetic products.

The depigmenting effect of natural resorcinol type polyphenols Kuwanon O and Sanggenon T from the roots of morus australis.

ETHNOPHARMACOLOGICAL RELEVANCE: Morus australis, one of the major Morus species growing in East Asia, is rich in phenolic compounds. The extract of M. australis has been used as skin whitening components for a long period. The action mechanisms of its principal constituents are still unclear. This study aims to evaluate the skin lightening effects of phenolic compounds extracted from the root of M. australis in different melanocyte systems and artificial skin models. MATERIALS AND METHODS: The depigmenting effect of resorcinol type polyphenols (RTPs) from the root extract of M. australis was evaluated in murine b16 and melan-a cell lines using a combined sulforhodamine B assay. Tyrosinase activity and the expression of melanogenesis proteins were evaluated for the mechanism study. The artificial skin model is used as a replacement of the animal test. RESULTS: Only Kuwanon O and Sanggenon T were found to have significant depigmenting effects in both murine b16 and melan-a cell lines. Their depigmenting mechanisms are slightly different in the two cell systems. In b16 cells, Kuwanon O and Sanggenon T, together with the other two RTPs, induced post-transcriptional degradations of MITF without suppressing its mRNA expression, leading to significant decreases of TRP-1 and TRP-2 production. While in melan-a cells, the levels of tyrosinase families were suppressed via MITF downregulation at both transcription and translation level by RTPs, with Kuwanon O inducing the greatest suppression. Further evaluations in artificial skin model demonstrated the outstanding depigmenting effects of Kuwanon O and Sanggenon T. CONCLUSIONS: Kuwanon O and Sanggenon T from M.australis root extract are two potential skin whitening ingredients. To screen resorcinol flavonone derivatives with an isoprenyl group in the Diels-Alder substituent might be an option for the search of potent hypopigmenting agents from plants.

Optimization of extraction conditions for osthol, a melanogenesis inhibitor from Cnidium monnieri fruits.

CONTEXT: Coumarin derivatives have been reported to inhibit melanin biosynthesis. OBJECTIVE: The melanogenesis inhibitory activity of osthol, a major coumarin of the fruits of Cnidium monnieri Cusson (Umbelliferae), and optimized extraction conditions for the maximum yield from the isolation of osthol from C. monnieri fruits were investigated. MATERIALS AND METHODS: B16F10 melanomas were treated with osthol at concentration of 1, 3, and 10 µM for 72 h. The expression of melanogenesis genes, such as tyrosinase, TRP-1, and TRP-2 was also assessed. For optimization, extraction factors such as extraction solvent, extraction time, and sample/solvent ratio were tested and optimized for maximum yield of osthol using response surface methodology with the Box-Behnken design (BBD). RESULTS: Osthol inhibits melanin content in B16F10 melanoma cells with an IC50 value of 4.9 µM. The melanogenesis inhibitory activity of osthol was achieved not by direct inhibition of tyrosinase activity but by inhibiting melanogenic enzyme expressions, such as tyrosinase, TRP-1, and TRP-2. The optimal condition was obtained as a sample/solvent ratio, 1500 mg/10 ml; an extraction time 30.3 min; and a methanol concentration of 97.7%. The osthol yield under optimal conditions was found to be 15.0 mg/g dried samples, which were well matched with the predicted value of 14.9 mg/g dried samples. CONCLUSION: These results will provide useful information about optimized extraction conditions for the development of osthol as cosmetic therapeutics to reduce skin hyperpigmentation.

Anti-melanogenic effects of Aster spathulifolius extract in UVB-exposed C57BL/6J mice and B16F10 melanoma cells through the regulation of MAPK/ERK and AKT/GSK3ß signalling.

OBJECTIVES: Pharmacological studies of Aster spathulifolius Maxim(AS) have demonstrated its anti-allergy, anti-viral and anti-obesity effects, however, its anti-melanogenic effects is still unclear. In this study, the effects of AS extract (ASE) on the inhibition of melanin synthesis were investigated in vitro and in vivo. METHODS: To perform this study, the contents of melanin and tyrosinase activity were analysed in B16F10 melanoma cells. Western blotting was carried out to determine the underlyling mechanism. Additionally, we investigated the effect of this extract on hyperpigmentation in C57bL/6J mice induced by 3, 6 and 9 weeks of UVB irradiation. KEY FINDINGS: AS extract led to reduced melanin synthesis through the regulation of MITF and its downstream signals. Furthermore, ASE increased the phosphorylation of MAPK/ERK and Akt/GSK3ß signalling pathway components. In vivo study, hypopigmentation effects were also observed. The melanocyte activity and the distribution of melanin granules were decreased in UVB-irradiated mice treated with ASE. CONCLUSIONS: These results suggest that the ASE may be promising as an active anti-melanogenic component, and further investigations should be performed regarding its potential as a whitening agent in the field of cosmetics.

Identification of HSP70-inducing activity in Arnica montana extract and purification and characterization of HSP70-inducers.

BACKGROUND: The expression of heat shock proteins (HSPs), particularly HSP70, is receiving considerable attention in the field of cosmetics, particularly given our recent report that ultraviolet-induced melanin production, skin damage and wrinkle formation were all suppressed in transgenic mice expressing HSP70. OBJECTIVE: In the present study, we searched for HSP70-inducers from a library of herbal extracts that have already been approved as quasi-pharmaceutical products in Japan. We selected an ethanol extract of Arnica montana (A. montana), based on its high HSP70-inducing activity and low cytotoxicity. METHODS: Cell viability was determined by MTT method and expression of HPS70 was monitored by immunoblotting analysis. RESULTS: From the extract, we purified and identified eight sesquiterpene lactones (AM1-8) as HSP70-inducers, among which AM-2 (helenalin 2-methylbutyrate) was selected due to its good HSP70-inducing properties and low cytotoxicity. Treatment of cultured mouse melanoma cells with AM-2 or A. montana extract up-regulated the expression of HSP70 in a dose-dependent manner. This treatment also activated heat shock factor-1, a transcription factor for hsp genes. Furthermore, pre-treatment of cells with AM-2 or A. montana extract decreased melanin production and expression and activity of tyrosinase. CONCLUSION: These results suggest that AM-2 and A. montana extract could be beneficial for use in hypopigmenting cosmetics as a consequence of their stimulatory effects on HSP70 expression.

Melanogenesis inhibitory effect of aerial part of Pueraria thunbergiana in vitro and in vivo.

Melanin is major factor that determines skin color as well as one of the defense systems that prevent the UV-induced damage. In case of abnormal concentration of melanin, skin diseases or problems occur such as albinism, leukoplakia, melasma, freckles, moles, and lentigo. With the lifespan of humans has been extended, importance of 'life quality' has been increased. White and clean skin is very important part of the satisfaction of appearance, especially for Asia women. The aim of this study was to find an anti-melanogenesis activity for which the aerial part of Pueraria thunbergiana can be utilized based on the increase in demands for cosmetics, particularly natural products. We demonstrated anti-pigmentation effects of aerial part of P. thunbergiana by measuring melanin content and through staining in the B16F10 melanoma cell line. The aerial part of P. thunbergiana decreased tyrosinase activity significantly in B16F10 cell cultures, while there is no direct effect on enzyme in cell-free conditions. To define the mechanisms, real-time PCR, western blot, glucosidase activity and antioxidant activity assay were implemented. As results, we demonstrated that aerial part of P. thunbergiana has anti-melanogenesis activity via two mechanisms. One is downgrading microphthalmia-associated transcription factor by activating Akt/GSK-3ß. Consequently, transcription of tyrosinase and tyrosinase-related protein 1 is decreased. Another is interrupting maturation of tyrosinase through inhibiting α-glucosidase. Furthermore, aerial part of P. thunbergiana showed great efficacy on pigmentation in vivo. These results suggest that aerial part of P. thunbergiana can be used as an anti-melanogenic agent.

Inhibitory effects of adlay extract on melanin production and cellular oxygen stress in B16F10 melanoma cells.

The aim of this study was to determine the effects of adlay extract on melanin production and the antioxidant characteristics of the extract. The seeds were extracted by the supercritical fluid CO2 extraction (SFE) method. The effect of adlay extract on melanin production was evaluated using mushroom tyrosinase activity assay, intracellular tyrosinase activity, antioxidant properties and melanin content. Those assays were performed spectrophotometrically. In addition, the expression of melanogenesis-related proteins was determined by western blotting. The results revealed that the adlay extract suppressed intracellular tyrosinase activity and decreased the amount of melanin in B16F10 cells. The adlay extract decreased the expression of microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase related protein-1 (TRP-1) and tyrosinase related protein-2 (TRP-2). The extract also exhibited antioxidant characteristics such as free radical scavenging capacity and reducing power. It effectively decreased intracellular reactive oxygen species (ROS) levels in B16F10 cells. We concluded that the adlay extract inhibits melanin production by down-regulation of MITF, tyrosinase, TRP-1 and TRP-2. The antioxidant properties of the extract may also contribute to the inhibition of melanogenesis. The adlay extract can therefore be applied as an inhibitor of melanogenesis and could also act as a natural antioxidant in skin care products.

Hypo-pigmenting effect of sesquiterpenes from Inula britannica in B16 melanoma cells.

During the course of screens to identify anti-melanogenic agents from natural resources, we found that the methanol extract of the dried flower of Inula britannica L. inhibited melanin synthesis in cultured melanoma cells stimulated with 3-isobutyl-1-methylxanthine (IBMX). A bioassay-guided isolation of the chloroform fraction of the I. britannica using an in vitro melanogenesis inhibition assay led to the isolation of sesquiterpenes, 1-O-acetylbritannilactone (1), britannilactone (2) and neobritannilactone B (3). Compounds 1 and 2 significantly reduced melanin production in a dose-dependent manner with IC50 values of 13.3 and 15.5 µM, respectively, whereas compound 3 was found to be cytotoxic. Compound 1 also inhibited the tyrosinase activity only in cell based-systems. Western blot analysis indicated that compound 1 inhibited melanogenesis by activating extracellular signal-regulated kinase (ERK) and Akt signaling and also inhibiting cAMP related binding protein, which regulates its downstream pathway, including tyrosinase, tyrosinase related protein-1 and TRP-2. These results demonstrated that compound 1, a major sesquiterpene from the flowers of I. britannica, exhibited anti-melanogenic activity by suppression of tyrosinase expression via ERK and Akt signaling. Taken together, our results suggest that these compounds may act as potent natural skin-lightening agents.

Acanthoic acid inhibits melanogenesis through tyrosinase downregulation and melanogenic gene expression in B16 melanoma cells.

The aim of this study was to investigate the in vitro inhibitory effects of acanthoic acid (ACAN), isolated from Acanthopanax koreanum, on melanogenesis and its related enzymes such as tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 in B16 melanoma cells. We found that ACAN significantly attenuates melanin synthesis and reduces the activity of intracellular tyrosinase, the rate-limiting melanogenic enzyme. Western blot analysis showed that ACAN also decreases tyrosinase, TRP-1, and TRP-2 protein expression. In addition, ACAN significantly decreased the expression of microphthalmia-associated transcription factor (MITF), a key regulator of melanogenesis. These results indicate that ACAN effectively inhibits melanin biosynthesis through down-regulation of MITF and thus could be useful as a new skin-whitening agent.

Octaphlorethol A isolated from Ishige foliacea inhibits α-MSH-stimulated induced melanogenesis via ERK pathway in B16F10 melanoma cells.

In this study, the potent skin-whitening effects of Octaphlorethol A (OPA) isolated from Ishige foliacea was investigated through inhibitory effect of melanin synthesis and tyrosinase activity in alpha-melanocyte stimulating hormone (α-MSH) induced B16F10 melanoma cells. OPA markedly inhibited melanin synthesis and tyrosinase activity in a concentration-dependent manner. We also found that OPA decreased microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 and -2 (TRP-1 and TRP-2) protein expressions. Moreover, OPA reduces p38 MAPK protein levels and activates extracellular signal-regulated kinase (ERK) and c-jun N-terminal kinases (JNKs) protein expressions in B16F10 cells. A specific ERK inhibitor PD98059 significantly blocks OPA-inhibited melanin synthesis and tyrosinase activity, whereas a p38MAP and JNK inhibitor had no effect. These findings provide evidence demonstrating that the anti-melanogenic effect of OPA is mediated through the activation of ERK signal pathway in B16F10 cells. These results indicate that OPA has the potential to be used as a melanogenesis inhibitor in the food and cosmetics industry.

Inhibition of melanin content by Punicalagins in the super fruit pomegranate (Punica granatum).

Current efforts to develop effective skin lightening products through the inhibition of melanin production have focused on compounds that inhibit the function and activity of tyrosinase, the rate-limiting enzyme in the melanin biosynthesis pathway. Synthetic tyrosinase inhibitors, such as hydroquinone, kojic acid, and arbutin, have been reported to cause skin irritation or acute dermatitis, raising concerns about the safety of these compounds. As a result, there is a need for safe natural ingredients that show effective skin lightening. In this report, we have identified a natural ingredient, pomegranate fruit extract, that inhibits melanin production in melanocytes and shows potential for use as a cosmetic skin lightening agent. In addition, we have identified a polyphenolic compound, punicalagins, as the active melanin inhibitor in pomegranate fruit extract based on its capacity to directly inhibit melanin production.