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.

N-(4-methoxyphenyl) caffeamide-induced melanogenesis inhibition mechanisms.

BACKGROUND: The derivative of caffeamide exhibits antioxidant and antityrosinase activity. The activity and mechanism of N-(4-methoxyphenyl) caffeamide (K36E) on melanogenesis was investigated. METHODS: B16F0 cells were treated with various concentrations of K36E; the melanin contents and related signal transduction were studied. Western blotting assay was applied to determine the protein expression, and spectrophotometry was performed to identify the tyrosinase activity and melanin content. RESULTS: Our results indicated that K36E reduced α-melanocyte-stimulating hormone (α-MSH)-induced melanin content and tyrosinase activity in B16F0 cells. In addition, K36E inhibited the expression of phospho-cyclic adenosine monophosphate (cAMP)-response element-binding protein, microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein-1 (TRP-1). K36E activated the phosphorylation of protein kinase B (AKT) and glycogen synthase kinase 3 beta (GSK3ß), leading to the inhibition of MITF transcription activity. K36E attenuated α-MSH induced cAMP pathways, contributing to hypopigmentation. CONCLUSIONS: K36E regulated melanin synthesis through reducing the expression of downstream proteins including p-CREB, p-AKT, p-GSK3ß, tyrosinase, and TRP-1, and activated the transcription factor, MITF. K36E may have the potential to be developed as a skin whitening agent.

Antioxidative and melanogenesis-inhibitory activities of caffeoylquinic acids and other compounds from moxa.

The MeOH extract of moxa, the processed leaves of Artemisia princeps PAMP. (Asteraceae), exhibited potent 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity and melanogenesis-inhibitory activity in α-melanocyte-stimulating hormone (α-MSH)-stimulated B16 melanoma cells. Eight caffeoylquinic acids, 1 and 6-12, five flavonoids, 13-17, two benzoic acid derivatives, 18 and 19, three coumarin derivatives, 20-22, four steroids, 23-26, and six triterpenoids, 27-32, were isolated from the MeOH extract. Upon evaluation of compounds 1, 6-23, and four semisynthetic caffeoylquinic acid esters, 2-5, for their DPPH radical-scavenging activity, 15 compounds, 1-13, 17, and 19, showed potent activities (IC(50) 3.1-16.8 µM). The 15 compounds exhibited, moreover, potent inhibitory activities (51.1-92.5% inhibition) against peroxidation of linoleic acid emulsion at 10 µg/ml concentration. In addition, when 27 compounds, 1-8, 10, 12, 13, 15-18, 20-25, and 27-32, were evaluated for their inhibitory activity against melanogenesis in α-MSH-stimulated B16 melanoma cells, five caffeoylquinic acids, i.e., chlorogenic acid (1), ethyl chlorogenate (3), propyl chlorogenate (4), isopropyl chlorogenate (5), and butyl chlorogenate (6), along with homoorientin (17) and vanillic acid (18), exhibited inhibitory activities with 33-62% reduction of melanin content at 100 µM concentration with no or almost no toxicity to the cells (89-114% of cell viability at 100 µM). Western blot analysis showed that compound 6 reduced the protein levels of microphtalmia-associated transcription factor (MITF), tyrosinase, tyrosine-related protein 1 (TRP-1), and TRP-2 mostly in a concentration-dependent manner, suggesting that this compound inhibits melanogenesis on α-MSH-stimulated B16 melanoma cells by, at least in part, inhibiting the expression of MITF, followed by decreasing the expression of tyrosinase, TRP-1, and TRP-2. Furthermore, four compounds, 13, 15, 16, and 30, exhibited cytotoxicities against HL60 human leukemia cell line (IC(50) 7.0-11.1 µM), and nine compounds, 14-16, 23, 26-28, 31, and 32, showed inhibitory effects (IC(50) 272-382 mol ratio/32 pmol 12-O-tetradecanoylphohrbol-13-acetate (TPA)) against Epstein-Barr virus early antigen (EBV-EA) activation induced by TPA in Raji cells.

Inhibition of melanogenesis by Xanthium strumarium L.

Xanthium strumarium L. (Asteraceae) is traditionally used in Korea to treat skin diseases. In this study, we investigated the effects of a X. strumarium stem extract on melanin synthesis. It inhibited melanin synthesis in a concentration-dependent manner, but it did not directly inhibit tyrosinase, the rate-limiting melanogenic enzyme, and instead downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase expression. MITF, the master regulator of pigmentation, is a target of the Wnt signaling pathway, which includes glycogen synthase kinase 3ß (GSK3ß) and ß-catenin. Hence, the influence of X. strumarium stem extract on GSK3ß and ß-catenin was further investigated. X. strumarium induced GSK3ß phosphorylation (inactivation), but the level of ß-catenin did not change. Moreover, a specific GSK3ß inhibitor restored X. strumarium-induced melanin reduction. Hence, we suggest that X. strumarium inhibits melanin synthesis through downregulation of tyrosinase via GSK3ß phosphorylation.

Suppression of α-MSH and IBMX-induced melanogenesis by cordycepin via inhibition of CREB and MITF, and activation of PI3K/Akt and ERK-dependent mechanisms.

Cordycepin has been a traditional medicine in China and Korea for centuries. This study explored the inhibitory effect of cordycepin on melanogenesis and the relative molecular mechanisms. Cordycepin inhibited melanin synthesis-related enzymes, such as tyrosinase, tyrosinase-related protein-1 (TRP1) and tyrosinase-related protein-2 (TRP2). α-MSH and IBMX were reported as melanin synthesis enhancers. Both of them could increase intracellular melanin synthesis by activation of the microphthalmia-associated transcription factor (MITF) signaling pathway. In the MITF pathway, the phosphorylation of cAMP related binding protein (CREB) activated the transcription of MITF, resulting in increasing melanin synthesis. Cordycepin also decreased the phosphorylation of CREB induced by α-MSH and IBMX in B16F10 melanoma cells. Accordingly, cordycepin inhibited melanogenesis signaling pathways by activating ERK and AKT signaling pathways to regulate the suppression of MITF and its downstream pathways including tyrosinase, TRP1 and TRP2. These results indicate the role of cordycepin as a potent depigmenting agent for cosmetics.

Inhibitory effect of mulberroside A and its derivatives on melanogenesis induced by ultraviolet B irradiation.

Mulberroside A was isolated from the ethanol extract of Morus alba roots. The enzymatic hydrolysis of mulberroside A with Pectinex produced oxyresveratrol and oxyresveratrol-3-O-glucoside. We tested oxyresveratrol, oxyresveratrol-3-O-glucoside, and mulberroside A to determine whether they could inhibit ultraviolet B (UVB) irradiation-induced melanogenesis in brown guinea pig skin. Topical application of mulberroside A, oxyresveratrol, and oxyresveratrol-3-O-glucoside reduced the pigmentation in guinea pig skin. These compounds suppressed the expression of melanogenic enzymes tyrosinase, tyrosinase-related protein-1, and microphthalmia transcription factor. The anti-melanogenesis effect was highest with oxyresveratrol, intermediate with oxyresveratrol-3-O-glucoside, and lowest with mulberroside A. Mulberroside A is a glycosylated stilbene of oxyresveratrol; thus, the deglycosylation of mulberroside A resulted in enhanced inhibition of melanogenesis. Histological analysis with Fontana-Masson staining confirmed that these compounds significantly reduced the melanin content in the epidermis of UVB-irradiated guinea pig skin compared to the vehicle control. Thus, these compounds effectively reduced pigmentation and may be suitable cosmetic agents for skin whitening.

Effect of saucerneol D on melanin production in cAMP-elevated melanocytes.

Intracellular cAMP stimulates microphthalmia-associated transcription factor (MITF) induction in melanocytes through cAMP-responsive element binding protein (CREB), which plays a pivotal role in the gene expression of tyrosinase for melanin biosynthesis. In the present study, saucerneol D as a lignan constituent of Saururus chinensis (Saururaceae family) efficiently inhibited melanin production with IC(50) values of 188-297 nM in B16 melanoma cells stimulated with α-melanocyte stimulating hormone (α-MSH) or other cAMP elevators. Moreover, saucerneol D down-regulated α-MSH-induced gene expression of tyrosinase at the transcription level in B16 cells, but it did not directly inhibit the catalytic activity of cell-free tyrosinase. As to the molecular basis of hypopigmenting action, saucerneol D inhibited α-MSH-induced phosphorylation of CREB in the cells, and sequentially suppressed MITF induction. Taken together, this study provides saucerneol D down-regulated the gene expression of tyrosinase, resulting in the inhibition of cAMP-induced melanin biosynthesis, and suggests pharmacological potential of the lignan structure in skin hyperpigmentation.

Inhibitory effect of Elephantopus mollis H.B. and K. extract on melanogenesis in B16 murine melanoma cells by downregulating microphthalmia-associated transcription factor expression.

In this study, the inhibitory effect of Elephantopus mollis H.B. and K. extract on melanogenesis in B16 murine melanoma cells was examined and possible mechanisms were elucidated. The melanin content in B16 cells decreased when they were treated with E. mollis extract. Inhibition was accompanied by reduced expression of tyrosinase (TYR) and tyrosinase-related protein 1 (TRP1). Furthermore, the expression level of microphthalmia-associated transcription factor (MITF), a major transcriptional regulator of genes encoding melanogenic enzymes such as Tyr and Trp1, decreased as assessed by western blotting and quantitative reverse transcriptase polymerase chain reaction (RT-PCR). These results suggest that E. mollis extract reduces melanogenesis by downregulating Mitf expression, leading to reduced expression of Tyr and Trp1. In addition, melanocortin-1 receptor (MC1R) expression was downregulated by E. mollis extract, suggesting desensitization to α-melanocyte-stimulating hormone (α-MSH) of cells treated with the extract.

Inhibition of skin pigmentation by an extract of Lepidium apetalum and its possible implication in IL-6 mediated signaling.

The development of effective skin-lightening agents is an increasingly important area of research aimed at the treatment of hyperpigmentation induced by UV irradiation or by medical conditions such as melasma, postinflammatory melanoderma and solar lentigo. Although some inhibit tyrosinase, identifying and understanding the mechanisms of action of other agents is an important goal if more effective pigmentation inhibitors are to be developed. We present here that an extract of Lepidium apetalum (ELA) decreased UV-induced skin pigmentation in brown guinea pigs and melanogenesis of HM3KO human melanoma cells. Interestingly, ELA did not reduce melanogenesis in HM3KO cells unless they were co-cultivated in keratinocyte-conditioned medium prepared by culturing keratinocytes with ELA. Under these conditions, ELA decreased tyrosinase mRNA and protein expression as well as melanin content via an ELA-mediated increase in keratinocyte IL-6 production which in turn was shown to decrease in the expression Mitf, a transcription factor implicated in tyrosinase gene expression and melanocyte differentiation. The results reveal that ELA may be an effective inhibitor of hyperpigmentation caused by UV irradiation or by pigmented skin disorders through a mechanism involving IL-6-mediated downregulation of Mitf rather than a direct inhibition of tyrosinase activity.