Human placental protein/peptides stimulate melanin synthesis by enhancing tyrosinase gene expression

Timeline of the Development of Skin-Lightening Active Ingredients in Japan

Japanese pharmaceutical cosmetics, often referred to as quasi-drugs, contain skin-lightening active ingredients formulated to prevent sun-induced pigment spots and freckles. Their mechanisms of action include suppressing melanin production in melanocytes and promoting epidermal growth to eliminate melanin more rapidly. For example, arbutin and rucinol are representative skin-lightening active ingredients that inhibit melanin production, and disodium adenosine monophosphate and dexpanthenol are skin-lightening active ingredients that inhibit melanin accumulation in the epidermis. In contrast, oral administration of vitamin C and tranexamic acid in pharmaceutical products can lighten freckles and melasma, and these products are more effective than quasi-drugs. On the basis of their clinical effectiveness, skin-lightening active ingredients can be divided into four categories according to their effectiveness and adverse effects. This review discusses academic research and development regarding skin-lightening ingredients in Japan.

Effects of oral administration of equine placental extract supplement on the facial skin of healthy adult women: A randomized, double-blind, placebo-controlled study

INTRODUCTION

Placenta extract is used as an ingredient in ointments for treating dermatological diseases, skin dryness, and for skin beautification. However, the clinical effects of the equine placenta on humans and the underlying mechanism of action are unclear. This randomized, controlled, double-blind study aimed to clinically evaluate the effect of oral intake of equine placental extract on human skin quality.

METHODS

Healthy women volunteers between the ages of 30 and 59 years (n = 29) were randomly assigned to receive 220 mg of equine placental extract-placebo orally, once daily for 4 weeks. Skin quality parameters such as skin hydration, skin barrier function (transepidermal water loss [TEWL]), and melanin index were assessed at baseline and after 4 weeks of administration.

RESULTS

The melanin index was significantly increased in the placebo group, whereas it remained unchanged in the equine placenta group. The pattern of melanin index change was significantly different due to intake or no intake of equine placenta supplements over 4 weeks. No significant difference was found in skin hydration and TEWL between the two groups at 4 weeks of postadministration. It was shown that the intake of the equine placenta was more effective in protecting the skin condition against the change of ultraviolet (UV) sensitively than the change in temperature and humidity.

CONCLUSIONS

Effect of equine placental extract intake was evident on the cheek skin of the equine placenta group where participants were protected from UV-induced pigmentation. Equine placental extract is useful for decreasing melanin synthesis and melanin content in the human skin and can be used as an effective food supplement to maintain human skin quality.

Polygonum multiflorum Thunb. Extract Stimulates Melanogenesis by Induction of COX2 Expression through the Activation of p38 MAPK in B16F10 Mouse Melanoma Cells

Polygonum multiflorum Thunb. (PM) root extracts have been used for treating graying hair in Oriental medicine; however, the molecular mechanisms underlying the melanogenic effects of PM root have not been fully understood. In the present study, we investigated the melanogenic effects of an ethanolic extract of PM root (PME) and the mechanisms involved. We examined the effects of PME on cell viability, cellular melanin content, and tyrosinase activity in B16F10 cells. The melanogenic mechanism of PME was explored using signaling inhibitors and examining the expression of melanogenic genes and signaling molecules by western blot and RT-qPCR analyses. PME did not exhibit any cytotoxicity in B16F10 cells compared to that in control cells. PME treatment significantly increased melanin production and tyrosinase activity. In addition, PME induced the expression of cyclooxygenase-2 (COX2) as well as that of melanogenic genes, such as microphthalmia-associated transcription factor (MiTF), tyrosinase-related protein (Trp) 1, Trp2, and tyrosinase, in B16F10 cells. PME treatment increased the level of phosphorylated p38 mitogen-activated protein kinase (MAPK), and pretreatment with SB 203580, a p38 MAPK inhibitor, significantly suppressed this PME-induced increase in the expression of COX2 and melanogenic genes. These results indicate that PME induced the expression of melanogenic genes by inducing COX2 expression via the activation of the p38 MAPK pathway, thereby contributing to the enhancement of melanogenesis.

Effect of human placental extract on menopausal symptoms, fatigue, and risk factors for cardiovascular disease in middle-aged Korean women

OBJECTIVE

In Korea, human placental extract (HPE) has recently been used to treat various diseases (chronic liver diseases, menopause syndrome, chronic fatigue, skin pigment diseases, etc.), but evidence-based studies are not yet sufficient. The aim of this study was to examine the effects of HPE on menopausal symptoms, fatigue, and risk factors for cardiovascular disease in middle-aged Korean women in a randomized controlled trial.

DESIGN

Korean women, aged 40 to 64 years, with menopausal symptoms and fatigue were recruited as participants. The women were randomly assigned to a placebo group or an HPE group. The HPE group received subcutaneous injections of HPE in the abdomen for 8 weeks, whereas the placebo group received normal saline. Then, the Menopause Rating Scale, and Fatigue Severity Scale, and Visual Analog Scale were administered, and risk factors for cardiovascular disease were assessed.

RESULTS

The Menopause Rating Scale total baseline score was not different between the two groups; however, the score of the HPE group decreased significantly at 8 weeks compared with that of the placebo group (P = 0.033). Fatigue Severity Scale and Visual Analog Scale scores of the placebo group did not change, whereas the scores of the HPE group decreased significantly during the study period (Fatigue Severity Scale, P = 0.002; Visual Analog Scale, P = 0.001). The baseline 17beta-estradiol level was not significantly different between the two groups, but the 17beta-estradiol level of the HPE group was significantly increased at 8 weeks compared with that of the placebo group (P = 0.031). No changes in risk factors for cardiovascular disease were observed in either group.

CONCLUSIONS

Menopausal symptoms and fatigue in middle-aged Korean women improved after 8 weeks of HPE treatment, whereas risk factors for cardiovascular disease did not change during the study period.

Activation of the Mitf promoter by lipid-stimulated activation of p38-stress signalling to CREB

The microphthalmia-associated transcription factor Mitf plays a critical role in regulating many aspects of melanocyte biology. It is required for melanoblast and postnatal melanocyte survival, regulates proliferation, and activates genes associated with differentiation such as tyrosinase and related genes involved in melanogenesis. Identifying the signals that regulate Mitf expression is crucial if we are to understand how cells of the melanocyte lineage respond to environmental cues. Here we show that the Mitf promoter is induced by lipid signalling via the p38 stress-activated kinase pathway that is also activated by a wide range of receptors as well as UV irradiation. Signalling via p38 leads to increased phosphorylation and activation of cyclic adenosine monophosphate response element-binding (CREB) that binds and activates the Mitf promoter via the cyclic adenosine monophosphate (cAMP) response element. Moreover, we also show that activation of p38 mediated by lipids is potentiated by inhibition of the PI3kinase pathway but not by inhibition of protein kinase A (PKA). The results identify a mechanism in which stress signalling via p38 leads to activation of CREB, enhanced Mitf expression and consequently increased tyrosinase expression. The results are relevant for the regulation of melanocytes by Mitf, but also raise the possibility that lipid mediated activation of p38 signalling may represent a potential therapy for vitiligo.