In human skin, inflammatory cytokines such as interleukin (IL)-1α and IL-1β are produced in keratinocytes by the stimulation of ultraviolet rays, and inflammation is induced. Suppression of inflammation is important in whitening because keratinocytes during inflammation produce melanocyte-stimulating factors such as endothelin-1 and prostaglandin, which lead to the formation of spots. Recently, IL-37 has been reported as an anti-inflammatory cytokine. IL-37 suppresses the release of inflammatory mediators such as inflammatory cytokines and plays a role as an inflammatory inhibitor within an organism. However, the function of IL-37 in human skin has not yet been fully elucidated. Therefore, we investigated the functions of IL-37 in the epidermis. First, we examined the localization of IL-37 in human skin by immunohistochemistry. IL-37 was detected in the granular layer of the epidermis in normal human skin. Next, we investigated the anti-inflammatory function of IL-37 in epidermis by using human keratinocyte cell line HaCaT. As a result, IL-37 significantly suppressed the increase in mRNA expression levels of inflammatory cytokines, melanocyte-stimulating related factors due to UVB irradiation. Furthermore, we also investigated the effects of UVB irradiation on IL-37 mRNA expression and protein level. UVB irradiation suppressed significantly both IL-37 mRNA expression and protein level. From the above results, it was suggested that IL-37 is expressed in the stratum granulosum of the human epidermis and has a function of suppressing the inflammatory reaction in the skin, and also suppresses the production of melanocyte-stimulating factors through that function. However, it was considered that the inflammatory resistance of IL-37, which is inherent in the skin, is reduced by the influence of UVB. In order to suppress skin inflammation and prevent the formation of spots, it is important to recover the decrease of IL-37 due to the effects of UVB and enhance the natural inflammatory resistance in one’s skin.

As anti-aging continues to gain worldwide attention, many people are becoming increasingly interested in beauty treatments that maintain beautiful skin free of discoloration and freckles by inhibiting melanogenesis. Sake lees, the lees resulting from sake production, have conventionally been used as a food product but may also have promise as an ingredient for cosmetics. To explore this potential, in this experiment, we investigated the tyrosinase inhibiting effects of sake lees extract.

Dried sake lees powder solutions were extracted using 20, 60, and 100°C distilled water and 20, 40, 60, 80, and 100% ethanol. The tyrosinase inhibiting effects of each extract were examined using tyrosinase from mushroom and 3,4-dihydroxy-L-phenylalanine substrate. The results confirmed that the 60°C water extract (stock solution and 100 times dilution of stock solution) and 60% ethanol extract (stock solution and 100 or 1000 times dilution of stock solution) significantly inhibited tyrosinase activity. These extracts are concluded to contain multiple tyrosinase-inhibiting ingredients. Sake lees extract is thus a promising ingredient for use in skin-whitening cosmetics.

Although “sensitive skin” is not an academic term that indicates skin symptoms, it is widely recognized by consumers and is a skin problem that cannot be ignored. It is not difficult to imagine that sensitive skin is closely related to modern life. In addition, due to seasonal changes and climate change such as new lifestyles, sensitive skin may be exposed to rapid changes in the external environment, which is considered to be one of the factors. In this paper, I would like to show about the relationship between changes in the external environment and sensitive skin. I would also like to mention that as a mechanism by which the barrier function and moisturizing function, which are important functions of the skin, are disturbed by changes in the external environment. In particular, this article introduces that Caspase14 (C14), which are both natural moisturizing factor (NMF) production-related enzymes and denucleation-related enzymes and NMF-producing enzyme Bleomycin Hydrolase (BH) become unstable due to climate changes. It has been clarified that the gene expression of C14 is reduced by changing to a low humidity or low temperature state. On the other hand, it is clarified that the gene expression of BH fluctuates depending on the season in Japan. It also reveals that this seasonal variation is no longer seen in patients with atopic dermatitis. These results show that the skin has a mechanism to flexibly maintain homeostasis against external environmental stimuli. However, it suggests that disruption of this mechanism may be involved in the formation of sensitive skin, including atopic dermatitis. In other words, in order to prevent sensitive skin, it is important to maintain skin function and homeostasis that are not disturbed by the external environment, which is one of the causes of sensitive skin.

The skin concentration of topically applied cosmetic active ingredients is very important for evaluating cosmetics. However, the direct measurement of drug concentration in the membrane has several problems. Generally, controlling the removal of the drug formulation from the membrane surface is very difficult. Hard cleaning of the membrane surface decreases the membrane concentration, whereas inadequate cleaning may leave the drug formulation on the membrane. In the present paper, relationship between skin permeation and skin concentration is shown and research results with verification result for utilization to dose setting method guideline for human long-duration trials (Safety) is also introduced. I hope this paper will be helpful to ensure the efficacy and safety of cosmetic products.

We have been conducting sensitive skin research for more than 50 years, when sensitive skin was not well known. The vulnerable stratum corneum barrier condition peculiar to sensitive skin is easily affected by various internal and external factors such as dryness, ultraviolet rays, pollen, air pollutants, and stress. And latest studies have also suggested that it is associated with temperature differences and skin-resident bacteria. In this paper, we will discuss our development of cosmetics for sensitive skin, which has been evolving by conducting research and development focusing on the vulnerable skin barrier unique to sensitive skin.

It is important for us to spend our daily lives comfortably and lively. To that end, cosmetic behavior in daily life has the power to modestly enrich and revitalize the mind as well as the skin. It is not only because it has a functional value to the skin, but also because it has an emotional or affective value that resonates the mind through the skin. Grounded in this belief, we have been studying the effects of cosmetics on the mind and the body for about 40 years. By demonstrating and quantifying these effects in a scientific manner, our aim is to lead development of ever better cosmetics and maximize the satisfaction of the user. This paper summarizes research findings on how skin care, makeup, and fragrance affect the mind and body through tactile, visual, and olfactory sensations by means of psychophysiological and affective engineering measurement techniques.