This study focused on black and white hairs in individuals over the age of 40 and analyzed qualitative changes of age-related hair. Water-related irregular shapes increased with aging for both high-and low-humidity conditions. Careful observance of the difference between black and white hair revealed that the water-related irregular shape of white hair increased. The result of real-time examinations of water behavior by means of Fourier-transform infrared (FT-IR) microscopy revealed an increase of water penetration and decrease of water holding capacity in white hair. The amount of carbonylated proteins, which have been known an indicator of aging, was significantly greater in white hair than black hair over the age of 50. These results suggested that the carbonylation of interior proteins changed water behavior and was the cause of hair shape. Furthermore, it was considered until now that carbonylated proteins could not return to their previous form, but reductive amination treatments using 5-ethyl-2-methylpyridine borane (PEMB) were revealed to reduce the amount of carbonylated proteins, improving water behavior and hair shape. From the above, further quality-of-life (QOL) improvements can be brought about by not only applying color correction to white hair with conventional coloring, but also combining this with hair shape correction based on reductive amination.

Touch sensation is one of the important factors to create emotional value in cosmetics. It has been reported that gentle facial touch, which is one of the skin-care behaviors, arouses pleasantness, and this consecutive facial gentle touch for 4 weeks improves the skin appearance scores evaluated by experts. To reveal the underlying mechanism of improvement of skin appearance by pleasant touch, we examined the involvement of oxytocin which is one of the hypothalamus hormones in healthy Japanese adult women. As a result, cheek-brush stroking on the forearm, which has been shown to arouse pleasantness and increase oxytocin levels, twice a day for 4 weeks increased basal salivary oxytocin levels, and the participants realized the changes in skin condition themselves after the consecutive pleasant touch. Additionally, basal salivary oxytocin levels showed weak but significant positive correlation with the skin appearance scores of fine skin texture, uniformity of skin tone, and radiance. Moreover, after the above-mentioned skin-care behavior improving the skin appearance, the differential changes in pleasantness ratings showed weak but positive correlation with the salivary oxytocin levels. Taken together, our results suggest that the increase in oxytocin levels induced by habitual pleasant touch in skin-care could be partly responsible for improving the skin appearance in healthy Japanese adult women.

In order to investigate in detail the internal structure changes in virgin black human hair keratin fibers resulting from bleaching treatments, the structure of cross-sections at various depths of black human hair, which had been impossible to analyze due to high melanin granule content, was directly analyzed using Raman spectroscopy. The gauche-gauche-gauche (GGG) content of the -SS- groups existing from the cuticle region to the center of cortex region of the virgin black human hair remarkably decreased, while the gauche-gauche-trans (GGT) and trans- gauche-trans (TGT) contents were not changed by performing the excessive bleaching treatment. In particular, it was found that not only the β-sheet and/or random coil content, but also the α-helix content existing throughout the cortex region of virgin black human hair decreased. In addition, the transmission electron microscope observation showed that the proteins in the cell membrane complex, the cuticle and cortex of the virgin black human hair were remarkably eluted by performing the excessive bleaching treatment. From these experiments, it can be concluded that the -SS- groups, which have a GGG conformation, decomposed and finally converted to cysteic acid, and the α-helix structure of some of the proteins existing in the keratin changed to the random coil structure, or was eluted from the cortex region, thereby leading to the change to the rough structure of the virgin black human hair after the excessive bleaching treatment.

Water is the best natural and sustainable cosmetic ingredient. Environmental awareness has been rising in recent years and the oil-free and water-based cleansing lotion market is growing. The characteristics of cleansing lotions—transparent appearance, low viscosity like water, and refreshing feeling—are preferred. However, there remains an issue that makeup can be removed insufficiently because the existing technology for cleansing lotion is based on an aqueous micellar solution of surfactants. In this study, we aimed at enhancing the removing capability of water-based cleansing lotion by using a self-assembly called a sponge phase with extremely low interfacial tension against lipophilic substances. Because of its structure swollen with a large amount of water, the sponge phase has interesting properties: transparent appearance and low viscosity, in spite of infinite aggregates assembled to form a three-dimensional network. We found that this phase can be obtained by controlling the phase equilibrium of a hydrophilic nonionic surfactant. By applying this technology to the cleansing lotion, we succeeded in the development of a new formula with high removing capability taking advantage of ultra-low interfacial tension, while retaining the water-like property. The technology is expected to be used not only for cosmetics that require good compatibility with skin, but also for any industrial applications that require ultra-low interfacial tension.

One of the most effective techniques to improve the color transfer resistance of lipsticks has been to use a film-forming resin in combination with a volatile oil that covers the lips with a hard film. However, color retention is difficult because the film is brittle and easily peels off. Additionally, it tends to cause a dry feeling when the volatile oil evaporates from the lips. In this study, we have developed a novel silicone resin for use in lipstick products with a greatly enhanced flexibility and hardness that is impossible to achieve through a combination of conventional silicone resins. To assess the performance of our new silicone resin, its flexibility, hardness, and curing process were compared against those of conventional silicone resins. In addition, the effects of the molecular weight and structure of the developed silicone resin were also evaluated. Results showed that our silicone resin forms a very uniform film with a high hardness and flexibility compared to a conventional film. In addition, its molecular weight and crosslink density are shown to be important for improving the curing rate. In order to confirm the usefulness of the developed silicone resin, we prepared a formulation and conducted a color transfer resistance test, color retention test, and 12-hour long-lasting test. Results revealed that the formulation shows extremely high color transfer resistance and color retention. In addition, we performed a dry feeling evaluation and a shrinkage evaluation in which the formulation using our developed silicone resin was compared against a formulation using conventional film-forming agent combinations. Results revealed that the newly developed product had no film shrinkage and a significantly reduced dry feeling.

Fine particles of titanium oxide (TiO₂) or zinc oxide (ZnO) with a diameter in the nanometer region are often used for cosmetic materials because they potentially have excellent optical properties such as transparency or ultraviolet (UV) light protection. This study proposes a method to improve UV protection properties of those particles through the optimization of manufacturing processes. The method is based on the application of a thin film spinning high speed mixer for the dispersion of TiO₂ fine particles. We investigated the effect of turbulent liquid flow produced by the mixer on the particle size distribution, storage stability and UV light protection properties. Using this technique, flocculation of fine particles was effectively disintegrated with increasing rotor speed to produce monodispersed uniform dispersion which showed sharp particle size distribution dependent upon the rotor speed of the mixer. In the case of a peripheral speed higher than 30 m/s, no precipitation was observed when the samples were left standing at room temperature more than a month. When we evaluated the UV light protection effects of TiO₂ fine particles, it was found that UV transmittance measured by spectrophotometer, and sun protection factor (SPF) obtained by an SPF analyzer remarkably improved when the peripheral speed of the mixer was raised. Interestingly, there was a critical rotor speed at 30 m/s which showed significant increase in SPF. This threshold was typical of thin film spinning high speed mixers but not observed with a conventional homogenizing mixer. This remarkable improvement may be the result of the sharp particle size distribution produced by the turbulent liquid flow at a higher range of rotor speed. We report on the importance of manufacturing processes that contribute to the quality of functional products.

The complex coacervation of an anionic surfactant with a cationic polymer is one of the most important formulation techniques for modern conditioning shampoos. This study investigated the amount of perfume retained by hair following shampooing in relation to the complex coacervate-forming abilities of various anionic surfactants, including cocoyl glutamate (CG) with a cationic hydroxyethyl cellulose (PQ10). d-Limonene, a commonly used fragrance, was included in our shampoo formulations. We examined anionic surfactant-PQ10 complex coacervates by diluting several model shampoos, which revealed that complex coacervates facilitate the retention of d-Limonene on hair. In particular, a shampoo containing CG and PQ10 exhibited high levels of CG-PQ10 complex coacervate; the shampooed hair retained a remarkable amount of limonene compared to other shampoos containing anionic surfactants, such as alkyl ether sulfates or acylsarcosinate, together with PQ10. The amount of d-Limonene retained on hair using the CG-PQ10 shampoo was found to be controlled by its salt and fatty acid concentrations, as well as the pH of the formulation. CG is a mild anionic surfactant that can be used in the skin-compatible pH range and is known to be highly biodegradable and environmentally friendly. Given the ability of CG to coacervate with cationic polymers over a wide range of CG concentrations in diluted shampoo, our results indicate that CG is a useful material for engendering shampoos with additional value.

A major cause of wrinkle formation, which has a significant effect on apparent age, is a decrease in dermal extracellular matrix (ECM). Normally, ECM is always synthesized and decomposed to maintain a balance, but when decomposition becomes dominant due to aging, the amount of ECM decreases and wrinkles are formed. There is also a cascade that promotes ECM degradation by exposure to ultraviolet (UV) light. When UV causes inflammation of the skin, cytokines called chemokines are secreted at the inflamed area. When one of them, IL-8, is secreted, it promotes neutrophil migration and is also involved in activation of neutrophils infiltrating the inflamed site. When neutrophils are activated, they secrete excess neutrophil elastase, which promotes ECM degradation and wrinkle formation. We have constructed a method for evaluating the migration activity of neutrophil-like cells, and applied a yeast culture extract derived from the flower of “Sasayuri” (Lilium japonicum) to the neutrophil-like cell migration activity inhibitory effect, and ECM synthesis promoting effect, in vivo. The effect of improving wrinkles was confirmed, and the importance of controlling neutrophil migration by IL-8 in anti-wrinkle efforts was found.