The main functions of cleansing surfactants in personal care applications are foaming and cleansing, though they often have negative effects both on humans and the environment as well. In the development of cleansing surfactants, mildness to the skin and the hair has long been the first priority, and now, their impact on the environment is finally becoming another major topic. Some aspects of the “mildness” of cleansing surfactants are reviewed to show approaches for optimized “mild” cleansing products.

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The blood and lymphatic vascular systems are the two major circulatory systems in the skin. The skin continuously receives nutrients and oxygen through the blood vessels, whereas excess water and wastes in the skin are taken up by lymphatic vessels, so that together they maintain skin homeostasis. Despite the indispensable roles of the lymphatic and blood vascular systems in the skin, very few detailed studies have been conducted on their histology and/or functions. First, we analyzed the alteration of the blood and lymphatic vasculature that causes intrinsic aging. Our previous report revealed that pericyte-covered blood vessels are significantly reduced in aged skin. On the other hand, here we showed that lymphatic tight junctions which connect lymphatic endothelial cells (LEC) are looser in aged skin. These data suggest an unstable structure of the circulatory system in aged skin. To investigate the molecular mechanism (s) of blood and lymphatic vascular changes that occur in the skin with age, we evaluated the function of Tie2 (endothelium-specific receptor tyrosine kinase 2) , which is known to be crucial for blood vascular maturation. We have previously demonstrated that Tie2 also promotes the stabilization of lymphatic vessels as well as blood vessels. Surprisingly, we found an age-dependent downregulation of Tie2 activation. This result indicates that the down-regulation of Tie2 activation that occurs with age disables the function of the vasculature as “a nutrient delivery and waste uptake system”. Finally, we found that Cinnamomum cassia Blume (Cinnamon) has a powerful potential to directly activate Tie2 in LEC. In addition, we isolated the Tie2 activating compound from Cinnamomum cassia Blume and determined the structure of the isolated compound as Syringaresinol. The activation of Tie2 induced by Cinnamomum cassia Blume promotes the stabilization of the lymphatic and blood vasculature, and could serve as a revolutionary new strategy to prevent skin aging because it directly counteracts alterations in those systems which disrupt the maintenance of skin homeostasis.

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To make eyes appear more attractive, it is necessary for mascara to curl eyelashes and separate each one from the others. Among ingredients, film-forming resin in mascara is known to affect the curl and separation of each eyelash. However, the relation of the film-forming resin's function to curling and separating eyelashes has not been investigated in detail. That caused a limitation in its ability to curl eyelashes significantly and separate each one. Thus, we hypothesized that we could create dramatic separate curl mascara by developing a mascara film with a high hardness and fast hardening speed. We succeeded in developing a new acrylic resin (SC resin) by selecting suitable monomers of acrylic resins. The SC resin led to a mascara that markedly curled the eyelashes and widely separated each one, producing more an attractive eye appearance.

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The development of methods for objectively and accurately assessing skin condition is an important challenge in cosmetics research. There are currently several promising methods for displaying assessment results that combine quantitative and numerical data with images and other visual data, and that are intuitively easy to understand at a glance. Softness and elasticity of skin are of particular interest to consumers, and while it is possible to show numerical data, it has been difficult to show visual data for these. We therefore attempted to develop a method for objectively assessing skin softness and elasticity that shows both numerical and visual data, and proposed the sphere-drop test. The sphere-drop test involves dropping a sphere from directly above the skin so that it free-falls in a perpendicular line, impacts the skin, and rebounds back, and filming the process with a high-speed camera adjacent to the impact area. This test gives both numerical and visual data on sphere displacement over time. One of the sphere-drop test parameters, compression time (t1+t2), showed a highly significant positive correlation with sensory evaluations for skin softness. Another parameter, rebound height (h2), showed a highly significant positive correlation with sensory evaluations for skin elasticity. As these parameters can be visualized with images in addition to numerical expressions, this method may be a new objective assessment method for visualization of mechanical properties of skin with strong tactile elements.

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Hair styling by heat treatment with a hair iron or curling iron has been frequently done. However, heat treatment causes much hair damage. In this work, we have studied heat damage and how to indicate heat damage. The change of cystine into lanthionine moieties of hair protein occurs with heat treatment. So, we checked whether the amount of lanthionine in hair could serve as an effective heat damage index. As a result, while the amount of cysteic acid was increased by bleach treatment and permanent treatment, the amount of lanthionine was increased by heat treatment. Additionally, we found the degradation of both moisturizing effect and physical strength of hair. Based on these, we concluded that the measurement of lanthionine in the hair was effective to indicate the heat damage to hair.

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