JP2010189300A - Beauty method for restoring skin damage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel beauty method for restoring skin damage. <P>SOLUTION: The beauty method comprises applying an external preparation for skin containing a compound having a sterol structure so as to facilitate restoration of skin damage. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a novel cosmetic method for repairing rough skin using a sterol compound.

  The stratum corneum located in the outermost layer of the skin protects the living body from the contact and penetration of foreign substances such as bacteria and harmful substances, and has a barrier function to keep the skin in a healthy state by preventing moisture evaporation from the body. When the barrier function is lowered, transepidermal water loss (TEWL) from the skin surface is increased, and the stratum corneum moisture is relatively lowered. When the skin crests (skins) consisting of skin grooves and skin hills become irregular due to a decrease in water content of the stratum corneum, the skin becomes rough and rough (Toshiro Sone et al., Cosmetic Society Journal Vol.15 No.2. Pp. 60-65 (1991)).

  It is known that intercellular lipids in the stratum corneum that play an important role in this barrier function are mainly composed of ceramide, free fatty acid and cholesterol, and form a lamellar structure (Bouwstra JA, et al. Acta Derm Venereol Suppl (Stockh). 2000; 208: pp. 23-30 .; Bouwstra JA, et al., Int J Cosmet Sci. 2008 Oct; 30 (5): p. 388).

  There is a surfactant as a component contained in a skin care cleaning agent or the like. Surfactants penetrate the stratum corneum, are absorbed by keratinous keratin, and mix with intercellular lipids (Friberg, SE et al., Colloids Surf. 1988, 30, pp.1-12; Rhein, LD Ibid. 1997, 48, pp.253-274). Furthermore, surfactants are known to damage skin by removing skin lipids such as fatty acids, fatty acid glycerides, cholesteryl esters, even if only a small amount of lipid is removed (Fulmer, AW et al., J. Invest. Dermatol. 1986, 86, pp. 598-602; Denda, M. et al., Arch. Dermatol. Res. 1994, 286, pp. 41-46; Ronald, RW et al , J. Invest. Dermatol. 1999, 113, pp. 960-966; Lopez, O. et al. Bioch. Et Biophy Acta 2000, 1508, pp. 196-209 and Ebba, B. et al., Inter J Phama. 2000, 195, pp.189-195).

  In the cosmetic industry, studies have been made to recover from the above-mentioned damage to the human stratum corneum. As an example, it is known that lipid membranes can be restored at least partially by using fats and oils as additives (Lawson, EE; Anigbogu, ANC; Williams, AC; Barry, BW; Edwards, HGM Spectrochimica Acta Part A 1998, 54, pp. 543-558).

  When the skin surface is treated with acetone / ether, intercellular lipids containing ceramide are eluted from the stratum corneum. Although elution of ceramide significantly reduces the water content in the stratum corneum, it is known that such water content can be restored to a normal level by applying ceramide to the skin surface and supplementing it (Imokawa, G. Akasaki, S .; Minematsu, Y .; Kawai, M. Arch. Dermatol. Res. 1989, 281, pp. 45-51.). If the ceramide composing the stratum corneum is lost, it is reasonable to make up for the ceramide.

Toshiro Sone et al., Cosmetic Society Vol.15 No.2. Pp. 60-65 (1991) Bouwstra JA, et al., Acta Derm Venereol Suppl (Stockh). 2000; 208: pp. 23-30. Bouwstra JA, et al., Int J Cosmet Sci. 2008 Oct; 30 (5): p. 388). Friberg, S. E. et al., Colloids Surf. 1988, 30, pp.1-12 Rhein, L. D. Ibid. 1997, 48, pp.253-274 Fulmer, A. W. et al., J. Invest. Dermatol. 1986, 86, pp. 598-602 Denda, M. et al., Arch. Dermatol. Res. 1994, 286, pp.41-46 Ronald, R. W. et al., J. Invest. Dermatol. 1999, 113, pp. 960-966 Lopez, O. et al. Bioch. Et Biophy Acta 2000, 1508, pp. 196-209 Ebba, B. et al., Inter J. Phama. 2000, 195, pp.189-195 Lawson, E. E .; Anigbogu, A. N. C .; Williams, A. C .; Barry, B. W .; Edwards, H. G. M. Spectrochimica Acta Part A 1998, 54, pp. 543-558 Imokawa, G .; Akasaki, S .; Minematsu, Y .; Kawai, M. Arch. Dermatol. Res. 1989, 281, pp. 45-51.

  An object of the present invention is to provide a cosmetic method for repairing rough skin by a novel mechanism, which is different from a conventionally known method for restoring a moisturizing function based on ceramide.

  It has been reported that the application of acetone / ether to the skin causes efflux of not only ceramide but also other intercellular lipids, resulting in a state close to skin diseases. Thus, it is considered that the state in which the intercellular lipid structure is greatly disturbed is different from the rough skin that occurs on a daily basis in examining the suitability of ingredients to be included in cosmetics and the like.

  On the other hand, when the present inventor applied a suitable concentration of a surfactant such as sodium dodecyl sulfate (SDS) to the skin, unlike the above-mentioned acetone / ether treatment, ceramide is hardly contained within a short time (within 1 day). It turns out that it does not leak. In addition, when various oils were applied to the stratum corneum damaged by the application of a surfactant, it was also found that oils having a sterol structure such as cholesterol and phytosterol are particularly effective for repairing the damage. Based on these findings, the present inventor concluded that a compound having a sterol structure, not ceramide, is an important factor for repairing rough skin, and completed the present invention.

  That is, the present invention includes the following inventions.

[1] A cosmetic method characterized by accelerating repair of rough skin by applying a skin external preparation containing a compound having a sterol structure on the skin.
[2] A skin external preparation containing one or more fatty acids selected from fatty acids having 12 to 18 carbon atoms is applied to the skin before, after, or simultaneously with the application of the external preparation for skin. ] Beauty method as described in.
[3] The cosmetic method according to [2], wherein the fatty acid is palmitic acid.
[4] The cosmetic method according to [1], wherein the external preparation for skin further contains one or more fatty acids selected from fatty acids having 12 to 18 carbon atoms.
[5] The cosmetic method according to [4], wherein the fatty acid is palmitic acid.

  Cholesterol, which is a major intercellular lipid component, regulates the fluidity of biological membranes. According to the present invention, by applying a compound having a sterol structure such as cholesterol to the skin, the rough skin state, that is, the intercellular lipid structure that has been disturbed by elution of cholesterol and palmitic acid, is immediately restored to a normal state. Can be built. This means the recovery of the skin barrier function, which is a different mechanism from the recovery of the moisturizing function using ceramide.

  The repair of the intercellular lipid structure in the stratum corneum by the sterol compound is also in line with the “corneo (the stratum corneum) growth theory” constructed by the applicant of the present application, in which the stratum corneum is brought up and maintained in total.

  The new rough skin repair mechanism using such sterol compounds is different from the conventional rough skin amelioration mechanism that moisturizers exhibit, and the development of a new stratum corneum care component targeting intercellular lipids. It also contributes to the development of new rough skin improvement agents.

FIG. 1A shows, from below, an untreated stratum corneum pseudo-substrate, the substrate after exposure to SDS solution, a stratum corneum pseudo-substrate after exposure to an ethanol solution instead of an SDS solution, and cholesterol and palmitic acid after exposure to an SDS solution. The infrared (IR) absorption spectrum of the said board | substrate (7 second-24 hours) after applying the ethanol solution containing the mixture of these is shown. FIG. 1B shows an IR absorption spectrum of the substrate (5 seconds to 24 hours) after applying the stratum corneum pseudo-substrate after exposure to the SDS solution and the palmitic acid-containing ethanol solution from the bottom. FIG. 1C shows an IR absorption spectrum of the substrate (6 seconds to 24 hours) after application of the stratum corneum lipid simulated substrate after exposure to the SDS solution and the ethanol solution containing cholesterol acid, from the bottom. FIG. 2 is a diagram showing the repairing effect of palmitic acid, cholesterol, and phytosterol on the stratum corneum lipid pseudo-substrate after SDS treatment by electron spin resonance (ESR) measurement. FIG. 3 is a diagram showing the effect of repairing a cosmetic general-purpose ingredient on the stratum corneum lipid pseudo-substrate after SDS processing, by ESR measurement. FIG. 4 is a diagram showing the effect of repairing the sterol oil content on the stratum corneum lipid pseudo-substrate after the SDS treatment by ESR measurement. FIG. 5 is a diagram showing the repairing effect of palmitic acid, cholesterol, and phytosterol on the stratum corneum lipid pseudo-substrate after SDS treatment by differential scanning calorimetry (DSC) measurement. FIG. 6 is a diagram showing the repair effect of phytosterol on the human stratum corneum after SDS treatment, expressed as a ratio of Corneometer measurement values. FIG. 7 is a diagram showing the repair effect of phytosterol on the human stratum corneum after SDS treatment in terms of TEWL ratio.

  The present invention provides a cosmetic method characterized by promoting the repair of rough skin by applying a solution containing a compound having a sterol structure on the skin.

  The term “compound having a sterol structure” as used herein is used synonymously with “sterol compound” in the present specification. From the viewpoint of repairing rough skin, a compound having a sterol structure is preferable.

  Among the sterol compounds, crystalline substances that are solid at room temperature such as cholesterol and phytosterol are applied to the skin after being dissolved in an appropriate solvent. According to an experiment using a skin stratum corneum intercellular lipid pseudo-substrate described later, when a sterol compound is applied to the substrate in which the intercellular lipid structure is disturbed by the addition of SDS, the conformation of the ceramide in the substrate is short. It is clear that it will be repaired in time (8 seconds). On the other hand, palmitic acid cannot repair the ceramide conformation in a short time like a sterol compound, but gradually permeates into the substrate and can restore the substrate to an untreated state. . Therefore, when the sterol compound is applied alone, for example, before, after, or simultaneously with the application of the sterol compound, a solution containing a fatty acid having 12 to 18 carbon atoms, preferably palmitic acid, is applied to the skin. It can be restored to an unprocessed state as compared with.

  When the above-mentioned sterol compound and fatty acid having 12 to 18 carbon atoms are powdered at room temperature such as palmitic acid and stearic acid, alcohols such as ethanol and isopropanol, hydrocarbon oils such as liquid paraffin, squalane and isododecane, Oils such as macadamia nut oil, sunflower oil and olive oil, jojoba oil, fatty acids other than carbon number 12-18 such as oleic acid, etc., or a mixture thereof are included in the external preparation for skin. These solvents are not limited to the specific ones listed, and any solvents can be used as long as they can dissolve the sterol compound and the fatty acid having 12 to 18 carbon atoms. On the other hand, when the sterol compound and the fatty acid having 12 to 18 carbon atoms are liquid at room temperature, they can be directly included in the external preparation for skin. Thus, in another aspect, the present invention provides a skin external preparation containing a sterol compound and / or a fatty acid having 12 to 18 carbon atoms as an active ingredient for repairing rough skin.

  In the skin external preparation, the sterol compound may be contained in an amount of 0.01 to 100% by weight, and the fatty acid having 12 to 18 carbon atoms may be contained in an amount of 0.01 to 100% by weight.

  The dosage form of the external preparation for skin is not limited to a solution, and may be any dosage form such as cream, ointment, gel, aerosol and the like. These ingredients, along with other optional ingredients, can be included in any skin care product such as lotions, emulsions, and the like.

  As an index for evaluating “skin roughness”, an increase in TEWL value (transdermal moisture transpiration) is generally known. According to this method, a state in which TEWL (transdermal moisture transpiration) has increased since before application of the test object is regarded as rough skin, and the degree of increase in TEWL is regarded as a state in which the barrier ability of the skin has decreased. . In the present invention, in order to evaluate rough skin in vitro, a substrate simulating the skin stratum corneum intercellular lipid developed by the present inventor (hereinafter referred to as “skin stratum corneum lipid simulated substrate” in the present specification). (Japanese Patent Application No. 2008-335319) is used to evaluate the disorder of the structure as rough skin. The substrate is a model membrane composed of three types of lipids (ceramide, palmitic acid and cholesterol) in which the stratum corneum having a complicated structure is simplified. In the present invention, the difference (spectral intensity, wave number shift of absorption band derived from compounded lipid, etc.) compared with the IR absorption spectrum of the untreated substrate is regarded as the degree of damage.

  A flat plate such as a cover glass, mica, or silicon wafer can be used as a base substrate on which a lipid film composed of the three types of lipids is formed. These lipid mixtures are dissolved in a solvent at a mass ratio of 20-70%: 10-60%: 20-40% (ceramide: palmitic acid: cholesterol). From the viewpoint of imitating the composition ratio of stratum corneum intercellular lipid present in the skin, the ratio of the mixed lipid is preferably a mass ratio of 2: 1: 1 (ceramide: palmitic acid: cholesterol). As the solvent, methanol, chloroform, hexane, acetone, ethyl acetate, or the like, or a mixture thereof can be used. The solvent is not limited to these specific solvents, and any solvent may be used as long as it can dissolve the lipid.

  After dissolving the lipid mixture in a solvent, the solution is spread on a flat plate, for example, a cover glass, and dried. Subsequently, the flat plate is melted in an oven at a high temperature (for example, 120 ° C.) and left to stand for a predetermined time in a nitrogen stream. After cooling to room temperature, the lipid pseudo-substrate of the present invention can be prepared by adding water to a flat plate and immersing it in humidification (for example, dipping in water for a long time or adding water). A method in which the solid lipid mixture is melted and then humidified is also possible.

  “Repair of rough skin” means that the disruption of intercellular lipid structure (lamellar structure) in the substrate caused by the application of the surfactant and its fluidity and order are restored to the state before the application of the surfactant. means. When a sterol compound alone and / or a mixture of sterol compound and palmitic acid was applied to the substrate, the IR spectrum showed the same profile as that of the untreated substrate after 8 seconds (FIGS. 1A and 1C). On the other hand, when palmitic acid was applied alone, it took 11 minutes for the IR spectrum to recover to the original profile (FIG. 1B). From these results, even when applied to actual skin, sterol compounds are considered to contribute to immediate repair of rough skin.

However, the dose and usage of the compound having a sterol structure and the fatty acid having 12 to 18 carbon atoms in the external preparation for skin are not particularly limited, and are appropriately determined depending on the dosage form and the rough skin condition to be treated. Typically, several times a day, for example, 1 to 3 times, an appropriate amount, for example, ^{2 to} 3 μL of a 3% by mass solution per square cm ^{2 is} rubbed directly into the skin, or the appropriate amount is soaked in gauze or the like. Can be applied to the skin.

Preparation of skin stratum corneum lipid mimic substrate Ceramide III (95.9%, 0.3 g) (Evonik Degussa, Essen, Germany), palmitic acid (0.15 g) (Nacalai Tesque, Kyoto, Japan) and cholesterol (0.15 g) (Nacalai Tesque, Kyoto, Japan) was dissolved in a mixed solvent of chloroform (50 cm ³ ) and methanol (10 cm ³ ). Subsequently, the lipid mixed solution (0.2 cm ³ ) was spread on an 18 × 18 mm cover glass and dried. The produced lipid mixed film was melted at 120 ° C. in an oven and then left in a nitrogen atmosphere at the same temperature for 1 hour. The sample was allowed to penetrate water for 24 hours after cooling to room temperature. Finally, it was stored in a desiccator containing saturated sodium chloride (75% relative humidity) until use.

Damage to skin stratum corneum intercellular lipid mimetic substrate by SDS Each of the prepared substrates was exposed to an aqueous SDS solution (5.0 mg / cm ³ ) and maintained for a different period of time. Produced in the substrate. The substrate damaged by the SDS exposure was washed with a small amount of water and dried before use.

Changes in chemical structure and composition in the substrate after exposure to an aqueous SDS solution were analyzed spectroscopically using IR absorption spectra. The IR absorption spectrum was obtained by measuring in a transmission mode using a KBr pellet on a Digilab FTS-60A spectrometer manufactured by Bio-Rad. All spectra were scanned 64 times on average between 4000 and 400 cm ⁻¹ .

  Moreover, the packed state of lipids in the substrate was confirmed by subjecting the damaged substrate to X-ray diffraction (XRD). X-ray diffraction (XRD) measurement was performed on a X-ray diffractometer (RAD-RC, manufactured by Rigaku Corporation, D8 Discover, manufactured by Bruker, Germany), and high-density CuKα radiation (λ = 0. 154 nm) under the conditions of 50 mA, 60 kV, and 40 mA, 40 kV.

  From the results of IR and XRD, it was found that when SDS was applied to the substrate, cholesterol and palmitic acid were eluted from the substrate. Specifically, cholesterol was eluted about 1 minute after application, and palmitic acid was eluted 5-6 minutes after application. On the other hand, although ceramide (especially ceramide III) was suggested that the structure of the amide group changed from α-helix to β structure 4 minutes after application, the substrate was not removed after 24 hours from application. Almost remained. These phenomena were also confirmed in human skin.

Restoration of lipid structure by addition of cholesterol and / or palmitic acid 1) Mixture containing equal amounts of cholesterol and palmitic acid in ethanol, 2) Palmitic acid alone, and 3) Cholesterol alone to 5.0 mg / cm ³ each The dissolved and damaged substrate was exposed to the solution for different periods of time and maintained. After washing and drying, IR absorption spectrum measurement was performed.

Evaluation of repair of substrate damaged by SDS exposure by IR spectrum The substrate after lipid exposure was compared with the IR absorption spectrum before exposure. The results are shown in FIGS. As shown in FIG. 1A, 1) the substrate that has been exposed to a mixed solution of cholesterol and palmitic acid, the absorption band of 1614cm ^-1 in the amide I (ceramide III) is recovered to 1640 cm ^-1 by exposure 8 seconds . This suggests that the structure of ceramide III has recovered from the β structure to the α helix. When the damaged substrate was exposed to a solution of 3) cholesterol alone, ceramide III similarly recovered from the β structure to the α helix (FIG. 1C). However, 2) When exposed to a solution of palmitic acid alone, the structure of amide I (ceramide III) did not recover (FIG. 1B). Thus, it can be seen that the addition of cholesterol affects the structure of the remaining ceramide III.

The absorption band at 1708 cm ^{−1 in} C═O stretching mode (derived from palmitic acid) increased in intensity gradually after 1) exposure to an ethanol solution of palmitic acid and cholesterol (FIG. 1A). On the other hand, the intensity of the 1378 cm ^-1 absorption band (derived from the COH in-plane variable angle mode of cholesterol) increased after 8 seconds of exposure when the solution of 1) was used. However, the 1708 cm ^-1 absorption band increased in intensity 11 minutes after exposure to 2) palmitic acid alone in ethanol (FIG. 1B), whereas the 1378 cm ^-1 absorption band 3) ethanol alone in cholesterol. The intensity increased 8 seconds after exposure to the solution (FIG. 1C). These results suggest that the penetration rate of cholesterol is faster than that of palmitic acid.

Examination of repair effect on SDS-treated stratum corneum by ESR measurement In order to examine the fluidity and order of the lamellar structure of the stratum corneum, ESR measurement was performed on the substrate before and after the lipid exposure. The SDS-treated stratum corneum was immersed in an ethanol solution of a test sample for 10 seconds, and then immersed in ethanol for 10 seconds to remove the test sample adsorbed on the stratum corneum. As a control, samples in which the untreated stratum corneum and the SDS-treated stratum corneum were each immersed in ethanol for 10 seconds were also prepared. For each treated stratum corneum, 5-DSA aqueous solution was applied and incubated at 37 ° C. for 1 hour, and then the stratum corneum was washed thoroughly with water and spread on a cover glass, and allowed to stand overnight in a desiccator with a relative humidity of 93%. And then subjected to ESR measurement. The measurement conditions are as follows. Equipment: JES-RE1X X-band (9 GHz) EPR spectrometer (JEOL), microwave power: 10 mW, time constant: 1 second, sweep time: 8 minutes, modulation: 0.2 mT, sweep width: 15 mT. The stratum corneum structure was evaluated by calculating an order parameter (S value).

1. 2. Addition of stratum corneum intercellular lipid-related substance Fig. 2 shows the measurement results of the stratum corneum immersed in an ethanol solution containing 0.25 mass% of palmitic acid, cholesterol and phytosterol, which are stratum corneum intercellular lipid-related substances, for 10 seconds. Shown in The vertical axis of the graph indicates the S value, and the larger the value, the higher the stratum corneum structure. The stratum corneum structure of the stratum corneum treated with SDS with respect to the untreated stratum corneum was deteriorated, and the S value was not changed even after ethanol treatment for 10 seconds. On the other hand, moderate repairing effect was observed for palmitic acid applied stratum corneum, and excellent repairing effect was observed for cholesterol as a sterol compound and phytosterol applied stratum corneum.

2. Addition of general cosmetic oils Liquid paraffin used as cosmetic general oils, glyceryl diisostearate, N-lauroyl-L-glutamate di (phytosteryl 2-octyldodecyl), olive oil, isostearic acid, methylpolysiloxane 3% by mass ethanol solution FIG. 3 shows the measurement results of the stratum corneum soaked for 10 seconds. The vertical axis of the graph indicates the S value, and the larger the value, the higher the stratum corneum structure. The stratum corneum structure of the stratum corneum treated with SDS with respect to the untreated stratum corneum was deteriorated, and the S value was not changed even after ethanol treatment for 10 seconds. In contrast, liquid paraffin, glyceryl diisostearate, olive oil applied stratum corneum, moderate restoration effect, isostearic acid, methylpolysiloxane applied stratum corneum did not so much, N-sterol compound N- The lauroyl-L-glutamate di (phytosteryl 2-octyldodecyl) treated stratum corneum showed an excellent repair effect.

3. Addition of sterol oil 3% by mass of polyoxyethylene phytosterol, polyoxyethylene polyoxypropylene phytosterol, N-lauroyl-L-glutamate di (phytosteryl-2-octyldodecyl), macadamia nut oil fatty acid phytosteryl which is an oil having a sterol structure The measurement results of the stratum corneum immersed in an ethanol solution for 10 seconds are shown in FIG. The vertical axis of the graph indicates the S value, and the larger the value, the higher the stratum corneum structure. The stratum corneum structure of the stratum corneum treated with SDS with respect to the untreated stratum corneum was deteriorated, and the S value was not changed even after ethanol treatment for 10 seconds. On the other hand, an excellent restoration effect was observed for all the sterol oil-treated horny layers examined.

Examination of the stratum corneum repair effect by DSC measurement The recovery of the lipid structure of the substrate after SDS treatment by the addition of stratum corneum intercellular lipid was examined by DSC measurement. As the stratum corneum intercellular lipid to be added, 1) palmitic acid, 2) cholesterol, and 3) phytosterol were used. Each lipid was dissolved in ethanol to a concentration of 0.25% by weight. The SDS-treated stratum corneum was applied to the ethanol solution for 10 seconds each, and then immersed in ethanol for 10 seconds to remove the test sample adsorbed on the stratum corneum. As a control, a sample in which the untreated stratum corneum and the SDS-treated stratum corneum were each immersed in ethanol for 10 seconds was also prepared (n = 1). The measurement conditions are as follows. Apparatus: DSC120 (SII), measurement cell: 15 μL silver, measurement conditions: temperature raised from 5 ° C. to 130 ° C. at 2 K / min. The results are shown in FIG.

  As is apparent from the results of FIG. 5, the untreated stratum corneum has a lipid-derived peak temperature around 64 ° C. The peak temperature decreased below 62 ° C. in the SDS-treated stratum corneum, and remained below 62 ° C. even when ethanol was applied for 10 seconds. However, the peak temperature recovered to the temperature indicated by the untreated stratum corneum by simply exposing the SDS-treated stratum corneum to an ethanol solution of cholesterol for 10 seconds. Moreover, the peak temperature derived from lipid also recovered significantly for phytosterol. A moderate recovery effect was obtained by adding an ethanol solution of palmitic acid.

  From the results of the above ESR and DSC, it is considered that the compound having a sterol structure contributes to the immediate restoration of the disorder of the lamellar structure of the stratum corneum and the fluidity and order. With regard to phytosterols that showed excellent stratum corneum repair effect, the repair effect was examined in an in vivo test using human stratum corneum.

Examination of the repair effect of phytosterol on SDS treatment in the human stratum corneum in vivo The forearm inner side was washed with soap and dried with a towel. After 30 minutes, mark the site to which phytosterol is applied, and use the Corneometer CM825PC (COLOGNE, Germany), Tevameter TM210 (Courage + Khazaka, Cologne, Germany) to determine the moisture content of the skin and the TEWL value. Was measured. Thereafter, 300 μl of 3 wt% SDS aqueous solution was patched to each application site for 30 minutes.

  Next, in order to remove SDS from the patch application site, the application site was washed with soap and allowed to stand for 30 minutes. Thereafter, the skin surface moisture content and TEWL value were measured using the Corneometer and Tevameter.

  An ethanol solution containing 0.25 wt% phytosterol (Nisshin Oil Co., Ltd., Tokyo, Japan) was applied to the application site, and allowed to stand for 30 minutes. Thereafter, the skin surface moisture content and TEWL value were measured using the Corneometer and Tevameter. The results are shown in FIGS.

  The skin surface moisture ratio (corneometer measured value ratio) and TEWL ratio with respect to untreated skin decreased after application of SDS (FIG. 6) and TEWL ratio increased (FIG. 7). This means that rough skin was caused by the application of SDS. In contrast, in the skin after addition of phytosterol, the skin surface moisture content ratio increased (FIG. 6) and the TEWL ratio decreased (FIG. 7). That is, not only cholesterol but also phytosterol, which is a plant-derived sterol compound, has been proven in actual skin to contribute to the recovery of rough skin.

  According to the cosmetic method of the present invention, a rough skin state can be recovered by applying a compound having a sterol structure to the skin without using ceramide. By utilizing a novel rough skin repairing mechanism using such a sterol compound, it becomes possible to develop a novel stratum corneum care component targeting intercellular lipids and, in turn, a novel rough skin improving agent.

Claims (5)

  A cosmetic method characterized by accelerating repair of rough skin by applying a skin external preparation containing a compound having a sterol structure on the skin.   The skin external preparation containing one or more fatty acids selected from fatty acids having 12 to 18 carbon atoms is applied to the skin before, after, or simultaneously with the application of the external preparation for skin. Beauty methods.   The cosmetic method according to claim 2, wherein the fatty acid is palmitic acid.   The cosmetic method according to claim 1, wherein the external preparation for skin further contains one or more fatty acids selected from fatty acids having 12 to 18 carbon atoms.   The cosmetic method according to claim 4, wherein the fatty acid is palmitic acid.

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