Acyl neutral amino acid ester

Abstract

PROBLEM TO BE SOLVED: To provide a compound that has excellent emollient properties and can improve horny layer functions.SOLUTION: A compound is represented by the following formula (1) [where A is a C2 to 10 linear or branched hydrocarbon group, B is C2 to 18 linear or branched hydrocarbon group, X is a C1 to 5 linear or branched hydrocarbon group].SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to acyl neutral amino acid esters and the like. [Background technology]

[0002] The stratum corneum has two functions: a moisturizing function that retains moisture inside the stratum corneum, and a barrier function that prevents the invasion of foreign substances (e.g., foreign bodies, viruses, and bacteria) from the outside world. Sebum, intercellular lipids, natural moisturizing factors, etc. are known to act on the stratum corneum function.

[0003] Profilaggrin stored in the granular layer of skin tissue is decomposed into filaggrin through dephosphorylation during keratinization. Filaggrin moves from the granular layer to the stratum corneum, where it binds and aggregates with keratin fibers to form a keratin pattern. Filaggrin is then decomposed into low molecules such as urocanic acid, which become natural moisturizing factors involved in water retention and ultraviolet absorption. Therefore, it is believed that the more the production of filaggrin is promoted, the more the amount of the decomposed natural moisturizing factors increases, and the moisturizing ability of the skin is improved.

[0004] The keratinocytes that make up the stratum corneum and the intercellular lipids that exist between the keratinocytes prevent foreign substances from entering from the outside world. Therefore, if the number or size of the keratinocytes is insufficient, gaps will appear in the stratum corneum, reducing its barrier function.

[0005] Around the keratinocytes, which contain structures in which keratin such as keratin 10 and filaggrin are aggregated, there exists the marginal zone, which is an extremely tough and huge insoluble structure that lines the cell membrane of the keratinocyte. The main structural elements of the marginal zone are proteins such as involucrin produced in spinous cells and loricrin produced in granular cells, which are cross-linked by enzymes such as transglutaminase (TG) 1. Therefore, it is thought that filaggrin, involucrin, transglutaminase 1, keratin 10, and loricrin strongly affect the formation of keratinocytes and are related to the barrier function of the skin.

[0006] It has been reported that the expression of filaggrin, involucrin, transglutaminase 1, keratin 10, and loricrin is promoted by specific peptides such as glycylproline (Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2014 / 175001 Summary of the Invention [Problem to be solved by the invention]

[0008] However, specific peptides such as glycylproline have a weak expression promoting effect on moisturizing-related proteins such as filaggrin, and are considered to be insufficient for improving the moisturizing ability of retaining moisture inside the stratum corneum.Such specific peptides also have a weak expression promoting effect on proteins related to the barrier function of skin, and are considered to be insufficient for improving the barrier function of suppressing the intrusion of foreign substances.In other words, such specific peptides are considered to be insufficient for improving keratin function.

[0009] In addition, maintaining moisture in the stratum corneum is very important for skin health, and if moisture retention could be achieved not only by maintaining moisture inside the stratum corneum but also by an action from outside the stratum corneum, it would be possible to maintain moisture in each layer more effectively. The function of improving the dryness of the stratum corneum and conditioning the stratum corneum, and the function of improving moisture retention (action outside the stratum corneum) are called emollient properties, but the above-mentioned specific peptides are not known to have emollient properties.

[0010] An object of the present invention is to provide a compound that can improve the stratum corneum function and has excellent emollient properties. [Means for solving the problem]

[0011] As a result of extensive research, the inventors have discovered that certain acyl neutral amino acid esters are promising components capable of improving stratum corneum function and having excellent emollient properties, and have thus completed the present invention.

[0012] That is, the present invention is as follows. [1] The following formula (1): [ka] [During the ceremony, A is a linear or branched hydrocarbon group having 2 to 10 carbon atoms; B is a linear or branched hydrocarbon group having 2 to 18 carbon atoms; and X is a linear or branched hydrocarbon group having 1 to 5 carbon atoms. [2] The compound represented by the formula (1) is represented by the following formula (2): [ka] [During the ceremony, A and B are the same as those in the above formula (1). The following formula (3): [ka] [During the ceremony, A and B are the same as those in the above formula (1). The following formula (4): [ka] [During the ceremony, A and B are the same as those in formula (1) above; or The following formula (5): [ka] [During the ceremony, A and B are the same as those in the above formula (1). [3] The compound of [1] or [2], wherein B is a linear or branched hydrocarbon group having 2 to 8 carbon atoms. [4] The compound of [3], wherein B is a straight-chain or branched-chain hydrocarbon group having 2 or 3 carbon atoms. [5] The compound according to any one of [1] to [4], wherein A is a linear or branched hydrocarbon group having 7 to 10 carbon atoms. [6] The compound according to any one of [1] to [4], wherein A is a linear or branched hydrocarbon group having 2 to 6 carbon atoms. [7] Any of the compounds [1] to [6], wherein the hydrocarbon groups in A, B and X are alkyl. [8] A composition comprising a compound according to any one of [1] to [7] and a carrier. [9] An external skin preparation comprising any one of the compounds according to [1] to [7].

[10] A cosmetic comprising any one of the compounds according to [1] to [7]. Effect of the Invention

[0013] The compound of the present invention can enhance the production of various proteins related to the improvement of stratum corneum function (e.g., the moisturizing ability to retain moisture inside the stratum corneum, and the barrier ability of the stratum corneum to suppress the intrusion of foreign substances from the outside world). The compounds of the present invention can also exhibit excellent emollient properties. Therefore, the compound of the present invention can improve the water retention in the stratum corneum. For example, the improvement in the water retention in the stratum corneum can be achieved from the inside or outside of the stratum corneum, or both. The compounds of the present invention can also be stably formulated with hydrophilic organic solvents and hydrophobic organic solvents (oils) within an effective concentration range. The compound of the present invention can also exhibit transparent properties in the mixed solution of the compound of the present invention and hydrophobic organic solvent (oil) and in the mixed solution of the compound of the present invention and hydrophilic organic solvent, so that it can give a high-class feeling in appearance and can avoid visual effects on skin.Therefore, the compound of the present invention has the advantage that it can reduce white residues caused by application, for example. [Brief description of the drawings]

[0014] [Figure 1] 1 is a diagram showing the amplification amount (relative value to the amplification amount of the control) of each moisturizing-related protein gene of octanoylvaline (Example 3: C8Val), octanoylalanine (Example 4: C8Ala), glycylproline (Comparative Example 2: Gly-Pro), and valine (Comparative Example 3: Val). The moisturizing-related protein genes tested are, from the left, genes encoding filaggrin, involucrin, transglutaminase 1 (TG1), keratin 10, and loricrin (same as in FIG. 2). [Diagram 2] FIG. 2 shows the amplification amount (relative to the amplification amount of the control) of each moisturizing-related protein gene for octanoyl leucine (Example 5: C8Leu), octanoyl isoleucine (Example 6: C8Ile), octanoyl glycine (Example 7: C8Gly), glycylproline (Comparative Example 2: Gly-Pro), and valine (Comparative Example 3: Val). [Diagram 3] 3 is a diagram showing the amplification amount (relative value to the amplification amount of the control) of each moisturizing-related protein gene of butanoyl valine (Example 8: C4Val), hexanoyl valine (Example 9: C6Val), octanoyl valine (Example 10: C8Val), decanoyl valine (Example 11: C10Val), lauroyl (dodecanoyl) valine (Example 12: C12Val) and methanoyl valine (Example 13: C2Val). The moisturizing-related protein genes tested are, from the left, genes encoding filaggrin, involucrin, and transglutaminase 1 (TG1). [Figure 4] FIG. 4 shows the amount of amplification of the filaggrin gene (relative to the amount of amplification of the control) for lauroyl valine (Example 14: C12Val), decanoyl valine (Example 15: C10Val), octanoyl valine (Example 16: C8Val), hexanoyl valine (Example 17: C6Val), butanoyl valine (Example 18: C4Val), and acetyl valine (Example 19: C2Val). [Diagram 5] FIG. 5 shows the amount of amplification of the filaggrin gene (relative to the amount of amplification of the control) for lauroylalanine (Example 20: C12Ala), decanoylalanine (Example 21: C10Ala), octanoylalanine (Example 22: C8Ala), hexanoylalanine (Example 23: C6Ala), and butanoylalanine (Example 24: C4Ala). [Figure 6] FIG. 6 shows the absorbance of lauroyl valine (Comparative Example 4: C12Val), decanoyl valine (Example 25: C10Val), octanoyl valine (Example 26: C8Val), hexanoyl valine (Example 27: C6Val), butanoyl valine (Example 28: C4Val), and acetyl valine (Example 29: C2Val) in cells (percentage of control absorbance). [Figure 7] Figure 7 shows HPLC (Shimadzu) chromatograms (measurement wavelength 210 nm) of N-octanoylalanine produced by hydrolysis of C8Ala-iPA in the presence or absence of esterase. In the chromatogram, an N-octanoylalanine peak is observed at 0.6 minutes elution time, and a C8Ala-iPA peak is observed at 1.7 minutes elution time. When C8Ala-iPA is reacted with esterase, the peak at 1.7 minutes decreases, and a new peak appears at 0.6 minutes. [Figure 8] Figure 8 shows HPLC (Shimadzu) chromatograms (measurement wavelength 210 nm) of N-octanoylalanine produced by hydrolysis of C8Ala-Et in the presence or absence of esterase. In the chromatogram, a peak of N-octanoylalanine is observed at 0.6 minutes elution time, and a peak of C8Ala-Et is observed at 1.2 minutes elution time. When C8Ala-Et is reacted with esterase, the peak at 1.2 minutes decreases, and a new peak appears at 0.6 minutes. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention provides a compound represented by the above formula (1).

[0016] A is a straight or branched chain hydrocarbon group having 2 to 10 carbon atoms. The number of carbon atoms in the hydrocarbon group in A may be, for example, 5 to 10. The hydrocarbon group in A is saturated or unsaturated. Examples of such hydrocarbon groups include alkyl, alkenyl, and alkynyl.

[0017] When A is an alkyl, the alkyl is a straight-chain or branched-chain alkyl having 2 to 10 carbon atoms. Examples and preferred examples of the number of carbon atoms of the alkyl in A are the same as the number of carbon atoms of the hydrocarbon group described above in A. Examples of the alkyl in A include ethyl, propyl (e.g., n-propyl, isopropyl), butyl (e.g., n-butyl, iso-butyl, sec-butyl, tert-butyl), pentyl (e.g., n-pentyl, iso-pentyl, neo-pentyl, 1-ethylpropyl), hexyl (e.g., n-hexyl, iso-hexyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 2-ethylbutyl), heptyl (e.g., n-heptyl, 1-methylhexyl), , 2-methylhexyl, 3-methylhexyl, 1,1-dimethylpentyl, 2,2-dimethylpentyl, 3,3-dimethylpentyl, 2-ethylpentyl), octyl (e.g., n-octyl, 1-methylheptyl, 2-methylheptyl, 3-methylheptyl, 1,1-dimethylhexyl, 2,2-dimethylhexyl, 3,3-dimethylhexyl, 2-ethylhexyl), nonyl (e.g., n-nonyl, 3,5,5-trimethylhexyl), and decanyl (e.g., n-decanyl).

[0018] When A is alkenyl, the alkenyl is a straight or branched alkenyl having 2 to 10 carbon atoms. Examples and preferred examples of the number of carbon atoms of the alkenyl in A are the same as the number of carbon atoms of the above-mentioned hydrocarbon group in A. Examples of the alkenyl in A include ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, and decenyl.

[0019] When A is alkynyl, the alkynyl is a straight or branched alkynyl having 2 to 10 carbon atoms. Examples and preferred examples of the number of carbon atoms of the alkynyl in A are the same as the number of carbon atoms of the above-mentioned hydrocarbon group in A. Examples of the alkynyl in A include ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, and decynyl.

[0020] Preferably, A is a straight or branched alkyl having 2 to 10 carbon atoms. Examples and preferred examples of the number of carbon atoms of the alkyl in A are the same as the number of carbon atoms of the above-mentioned hydrocarbon group in A. Specific examples of such alkyl are as described above.

[0021] In a specific embodiment, the group in A may have 7 to 10 carbon atoms (preferably 8 to 10). When the group in A has 7 to 10 carbon atoms, the compound represented by the above formula (1) has the advantage of being able to significantly induce the expression of genes encoding various proteins related to the improvement of stratum corneum function. Examples of such proteins include proteins that can generate natural moisturizing factors in skin tissues (e.g., filaggrin, profilaggrin), and proteins that can be involved in skin barrier function (e.g., filaggrin, involucrin, transglutaminase 1, keratin 10, loricrin).

[0022] In another specific embodiment, the group in A may have 6 or less carbon atoms (i.e., 2 to 6). Even if the group in A has 6 or less carbon atoms, the compound represented by the above formula (1) has a partition coefficient (LogP) in the range of 1 to 4 and a molecular weight of 500 Da or less, and therefore has the advantages of being excellent in surface absorbency and capable of being provided in the stratum corneum at a high concentration.

[0023] B is a straight or branched chain hydrocarbon group having 2 to 18 carbon atoms. The number of carbon atoms in the hydrocarbon group in B is preferably 2 to 15, more preferably 2 to 12, even more preferably 2 to 8, still more preferably 2 to 6, and particularly preferably 2 or 3. The hydrocarbon group in B is saturated or unsaturated. Examples of such hydrocarbon groups include alkyl, alkenyl, and alkynyl.

[0024] When B is an alkyl, the alkyl is a straight-chain or branched-chain alkyl having 2 to 18 carbon atoms. Examples and preferred examples of the number of carbon atoms of the alkyl in B are the same as the number of carbon atoms of the hydrocarbon group described above in B. Examples of the alkyl in B include ethyl, propyl (e.g., n-propyl, isopropyl), butyl (e.g., n-butyl, iso-butyl, sec-butyl, tert-butyl), pentyl (e.g., n-pentyl, iso-pentyl, neo-pentyl, 1-ethylpropyl), hexyl (e.g., n-hexyl, iso-hexyl, 1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, 2-ethylbutyl), heptyl (e.g., n-heptyl, 1-methylhexyl, 2-methylhexyl, 3-methylhexyl, 1,1-dimethylpentyl, 2,2-dimethylpentyl, 3,3-dimethylpentyl, 2-ethylpentyl), octyl (e.g., n- Examples of the alkyl group include octyl, 1-methylheptyl, 2-methylheptyl, 3-methylheptyl, 1,1-dimethylhexyl, 2,2-dimethylhexyl, 3,3-dimethylhexyl, 2-ethylhexyl), nonyl (e.g., n-nonyl, 3,5,5-trimethylhexyl), decanyl (e.g., n-decanyl), undecanyl (e.g., n-undecanyl), dodecanyl (e.g., n-dodecanyl), tridecanyl (e.g., n-tridecanyl), tetradecanyl (e.g., n-tetradecanyl), pentadecanyl (e.g., n-pentadecanyl), hexadecanyl (e.g., n-hexadecanyl), heptadecanyl (e.g., n-heptadecanyl), and octadecanyl (e.g., n-octadecanyl).

[0025] When B is alkenyl, the alkenyl is a straight or branched alkenyl having 2 to 18 carbon atoms. Examples and preferred examples of the number of carbon atoms of the alkenyl in B are the same as the number of carbon atoms of the above-mentioned hydrocarbon group in B. Examples of the alkenyl in B include ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, and octadecenyl.

[0026] When B is alkynyl, the alkynyl is a straight or branched alkynyl having 2 to 18 carbon atoms. Examples and preferred examples of the number of carbon atoms of the alkynyl in B are the same as the number of carbon atoms of the above-mentioned hydrocarbon group in B. Examples of the alkynyl in B include ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, decynyl, undecynyl, dodecynyl, tridecynyl, tetradecynyl, pentadecynyl, hexadecynyl, heptadecynyl, and octadecynyl.

[0027] Preferably, B is a straight or branched alkyl having 2 to 18 carbon atoms. Examples and preferred examples of the number of carbon atoms of the alkyl in B are the same as the number of carbon atoms of the above-mentioned hydrocarbon group in B. Specific examples of such alkyl are as described above.

[0028] X is a straight or branched chain hydrocarbon group having 1 to 5 carbon atoms. The number of carbon atoms in the hydrocarbon group in X may be, for example, 1 to 4. The hydrocarbon group in X is saturated or unsaturated. Examples of such hydrocarbon groups include alkyl, alkenyl, and alkynyl.

[0029] When X is an alkyl, the alkyl is a straight-chain or branched-chain alkyl having 1 to 5 carbon atoms. Examples and preferred examples of the number of carbon atoms of the alkyl in X are the same as the number of carbon atoms of the above-mentioned hydrocarbon group in X. Examples of the alkyl in X include methyl, ethyl, propyl (e.g., n-propyl, isopropyl), butyl (e.g., n-butyl, iso-butyl, sec-butyl, tert-butyl), and pentyl (e.g., n-pentyl, iso-pentyl, neo-pentyl, 1-ethylpropyl).

[0030] When X is alkenyl, the alkenyl is a straight or branched alkenyl having 2 to 5 carbon atoms. Examples and preferred examples of the number of carbon atoms of the alkenyl in X are the same as the number of carbon atoms of the above-mentioned hydrocarbon group in X. Examples of the alkenyl in X include ethenyl, propenyl, butenyl, and pentenyl.

[0031] When X is alkynyl, the alkynyl is a straight or branched alkynyl having 2 to 5 carbon atoms. Examples and preferred examples of the number of carbon atoms of the alkynyl in X are the same as the number of carbon atoms of the above-mentioned hydrocarbon group in X. Examples of the alkynyl in X include ethynyl, propynyl, butynyl, and pentynyl.

[0032] Preferably, X is a straight or branched alkyl having 1 to 5 carbon atoms. Examples and preferred examples of the number of carbon atoms of the alkyl in X are the same as the number of carbon atoms of the above-mentioned hydrocarbon group in X. Specific examples of such alkyl are as described above.

[0033] Preferably, the compound represented by the formula (1) is a compound represented by any one of the formulae (2) to (5). With respect to A and B in the compounds represented by the formulae (2) to (5), the definitions, examples, preferred examples and specific examples of the hydrocarbon group (e.g., alkyl, alkenyl, alkynyl) and the number of carbon atoms are the same as those described above for the formula (1).

[0034] In a specific embodiment, A and B in the compounds represented by the formulae (2) to (5) may each independently have different numbers of carbon atoms and different hydrocarbon groups. For example, A in the compounds represented by the formulae (2) to (4) may be a linear or branched chain hydrocarbon group having 2 to 10 carbon atoms, and A in the compound represented by the formulae (5) may be a linear or branched chain hydrocarbon group having 6 or less carbon atoms, or 7 to 10 (preferably 8 to 10) carbon atoms. Also, A in the compounds represented by the formulae (2) to (4) may be a linear or branched chain hydrocarbon group having 2 to 10 carbon atoms, and A in the compound represented by the formulae (5) may be a linear or branched chain hydrocarbon group having 7 to 10 (preferably 8 to 10) carbon atoms. Furthermore, A in the compounds represented by the formulae (2) to (4) may be a linear or branched chain hydrocarbon group having 5 to 10 carbon atoms, and A in the compound represented by the formulae (5) may be a linear or branched chain hydrocarbon group having 7 to 10 (preferably 8 to 10) carbon atoms.

[0035] The compounds represented by the formulae (1) to (5) correspond to N-acyl neutral amino acid esters (neutral amino acid derivatives). The compounds represented by the formulae (1) to (5) may be optical isomers (L-form or D-form) with respect to the nitrogen atom, the carbon atom of the carbonyl group, and the carbon atom to which X is bonded, or may be a mixture thereof. Preferably, the compounds represented by the formulae (1) to (5) are L-forms.

[0036] The preparation of the compound of the present invention can be suitably carried out by reacting N-acyl neutral amino acid and alcohol. The reaction of N-acyl neutral amino acid and alcohol can be carried out by a general method for producing an ester from a carboxylic acid compound and an alcohol. Such reactions are well known in the art. For example, the reaction can be carried out by appropriately adding a catalyst. The reaction can also be carried out at an appropriate temperature (e.g., 15 to 200°C) for several hours (e.g., 0.5 to 8 hours). More specifically, the preparation of the compound of the present invention can be carried out by the method of Production Example A described below. The preparation of the compound of the present invention can also be carried out in the same manner as the method described in JP-A-11-240828, except that the types of N-acyl neutral amino acid and alcohol are changed in the method described in JP-A-11-240828. The compound of the present invention can be suitably purified by any purification method (e.g., extraction) used in the field of organic synthesis.

[0037] The compound of the present invention is useful as an agent for improving keratin function and a moisturizing agent, and for the development of products such as cosmetics, medicines, and quasi-drugs. The compound of the present invention may be provided in the form of a composition containing the compound of the present invention and a carrier (e.g., a carrier acceptable as a cosmetic, medicine, or quasi-drug). Examples of such carriers include thickeners, stabilizers, pH adjusters, preservatives, UV protection agents, fragrances, and dyes. The specific types and amounts of these components can be appropriately set. Such compositions can be prepared as compositions in any state. Examples of such compositions include liquid compositions, cream compositions, emulsion compositions, powder compositions, stick compositions, and sheet-impregnated compositions.

[0038] For example, the compound of the present invention can be used by applying (e.g., spreading, administering) an effective amount (e.g., 0.001 mg to 10 g) to a desired site (e.g., skin, hair, body hair, scalp) of a subject (e.g., mammals such as humans, animals such as birds and reptiles). Preferably, the compound of the present invention is applied to humans. The condition of the subject to which the compound of the present invention is applied is a healthy condition or an abnormal condition (e.g., disease). Examples of such abnormal conditions include rough skin, dry skin, scales, disturbance of turnover, and skin diseases (e.g., dermatitis such as atopic dermatitis).

[0039] The compound of the present invention may also be a cosmetic or topical agent. The cosmetic or topical agent of the present invention may be prepared in any form that can be applied to a desired site (e.g., skin, hair, scalp) according to a conventional method.

[0040] The compound of the present invention can be preferably used as a cosmetic or topical agent for the skin, hair, or scalp. Examples of the cosmetic or topical agent for the skin include milky lotion, lotion, cream, gel, beauty essence, and face mask. Examples of the cosmetic or topical agent for the hair include hair milky lotion, hair treatment, hair conditioner, shampoo, and hair lotion. Examples of the cosmetic or topical agent for the scalp include hair growth agents. Examples of the preferred cosmetic include leave-on cosmetic, milky lotion, lotion, cream, gel, beauty essence, and face mask. Examples of the preferred topical agent include ointments, creams, mousses, and gels. EXAMPLES

[0041] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to the following examples. All of the N-acyl neutral amino acids used as starting materials in the following production examples are L-form.

[0042] Preparation Example A: Synthesis of N-acyl neutral amino acid ester from alcohol and N-acyl neutral amino acid N-acyl neutral amino acid (0.14 mol) was added to ethanol (320 mL, 5.48 mol) or isopropyl alcohol (418 mL, 5.48 mol) and mixed. p-Toluenesulfonic acid monohydrate (5.3 g, 0.03 mol) was added to the mixture, and a reflux condenser was attached to prevent the alcohol from evaporating, followed by stirring at a bath temperature of 125°C for 3 hours. The product was concentrated under reduced pressure in vacuum, then diluted with ethyl acetate (600 mL) and washed four times with saturated sodium bicarbonate water (240 mL). The organic phase was further washed twice with ultrapure water (480 mL). Water was removed from the organic layer using sodium sulfate. Furthermore, sodium acid was removed by filtration, and the organic layer was concentrated under reduced pressure in vacuum to obtain the product (acyl neutral amino acid ester).

[0043] Production Example 1: Production of N-octanoylalanine isopropyl ester (C8Ala-iPA)

[0044] [ka]

[0045] N-octanoylalanine (C8Ala, 30.00 g, 0.14 mol) was used as the N-acyl amino acid, and isopropyl alcohol (418 mL, 5.48 mol) was used as the alcohol. The reaction was carried out according to the synthesis method of Production Example A to obtain C8Val-iPA (yield 97%).

[0046] 1 H-NMR(400MHz,CDCl3,rt):δ6.077-6.093(1H,d,J=6.4Hz),5.015-5.078(1H,sep,J=6.4Hz),4.511-4.583(1H,quint,J=7.2Hz),2.184-2.22 2(2H,t,J=7.6Hz),1.599-1.669(2H,quint,J=7.2Hz),1.372-1.390(3H,d,J=7.2Hz)1.244-1.298(14H,m),0.859-0.892(3H,t,J=6.8Hz)ppm.

[0047] ESI-MS(positive) m / z 258.2[M+H] + , 280.1[M+Na] +

[0048] Production Example 2: Production of N-octanoyl valine isopropyl ester (C8Val-iPA)

[0049] [ka]

[0050] N-octanoyl valine (C8Val, 34.06 g, 0.14 mol) was used as the N-acyl amino acid, and isopropyl alcohol (418 mL, 5.48 mol) was used as the alcohol. The reaction was carried out for 8 hours according to the synthesis method of Production Example A to obtain C8Val-iPA (yield 93%).

[0051] 1 H-NMR(400MHz,CDCl3,rt):δ5.955-5.976(1H,d,J=8.4Hz),5.024-5.087(1H,sep,J=6.4Hz),4.528-4.561(1H,dd),2.216-2.254(2 H,t,J=7.2Hz),2.135-2.182(1H,sex,J=6.8Hz),1.610-1.765(2H,quint,J=7.2Hz),1.256-1.314(14H,m),0.860-0.949(9H,m)ppm.

[0052] ESI-MS(positive) m / z 286.2[M+H] + , 308.1[M+Na] +

[0053] Production Example 3: Production of N-octanoylglycine isopropyl ester (C8Gly-iPA)

[0054] [ka]

[0055] N-octanoylglycine (C8Gly, 28.18 g, 0.14 mol) was used as the N-acyl amino acid, and isopropyl alcohol (418 mL, 5.48 mol) was used as the alcohol. The reaction was carried out according to the synthesis method of Production Example A to obtain C8Gly-iPA (yield 97%).

[0056] ESI-MS(positive) m / z 244.1[M+H] + , 266.1[M+Na] +

[0057] Production Example 4: Production of N-octanoylisoleucine isopropyl ester (C8Ile-iPA)

[0058] [ka]

[0059] N-octanoylisoleucine (C8Ile, 36.03 g, 0.14 mol) was used as the N-acyl amino acid, and isopropyl alcohol (418 mL, 5.48 mol) was used as the alcohol. The reaction was carried out according to the synthesis method of Production Example A to obtain C8Ile-iPA (yield 71%).

[0060] ESI-MS(positive) m / z 300.2[M+H] + ,322.2[M+Na] +

[0061] Production Example 5: Production of N-octanoyl leucine isopropyl ester (C8Leu-iPA)

[0062] [ka]

[0063] N-octanoylleucine (C8Leu, 36.03 g, 0.14 mol) was used as the N-acyl amino acid, and isopropyl alcohol (418 mL, 5.48 mol) was used as the alcohol. The reaction was carried out according to the synthesis method of Production Example A to obtain C8Leu-iPA (yield 97%).

[0064] ESI-MS(positive) m / z 300.2[M+H] + ,322.2[M+Na] +

[0065] Production Example 6: Production of N-lauroylisoleucine isopropyl ester (C12Ile-iPA)

[0066] [ka]

[0067] N-lauroylisoleucine (C12Ile, 43.89 g, 0.14 mol) was used as the N-acyl amino acid, and isopropyl alcohol (418 mL, 5.48 mol) was used as the alcohol. The reaction was carried out according to the synthesis method of Production Example A to obtain C12Ile-iPA (yield 85%).

[0068] ESI-MS(positive) m / z 356.3[M+H] + , 378.2[M+Na] +

[0069] Production Example 7: Production of N-octanoylalanine ethyl ester (C8Ala-Et)

[0070] [ka]

[0071] N-octanoylalanine (C8Ala, 30.00 g, 0.14 mol) was used as the N-acyl amino acid, and ethanol (320 mL, 5.48 mol) was used as the alcohol. The reaction was carried out according to the synthesis method of Production Example A to obtain C8Val-Et (yield 90%).

[0072] 1 H-NMR(400MHz,CDCl3,rt):δ6.063-6.078(1H,d,J=6.0Hz),4.552-4.624(1H,quint,J=7.2Hz),4.176-4.230(2H,q, J=7.2Hz),2.186-2.224(2H,t,J=7.6Hz),1.599-1.670(2H,quint,J=7.2Hz), 1.389-1.407(3H,d,J=7.2Hz)1.267-1.302(11H,m),0.860-0.892(3H,m)ppm.

[0073] ESI-MS(positive) m / z 244.2[M+H] + , 266.1[M+Na] +

[0074] Production Example 8: Production of N-octanoyl valine ethyl ester (C8Val-Et)

[0075] [ka]

[0076] N-octanoylvaline (C8Val, 34.06 g, 0.14 mol) was used as the N-acyl amino acid, and ethanol (320 mL, 5.48 mol) was used as the alcohol. The reaction was carried out for 8 hours according to the synthesis method of Production Example A to obtain C8Val-Et (yield 93%).

[0077] 1H-NMR(400MHz,CDCl3,rt):δ5.952-5.973(1H,d,J=8.4Hz),4.557-4.591(1H,dd),4.159-4.241(2H,m),2.217-2.255(2H,t,J =7.2Hz),2.121-2.202(1H,sex,J=6.8Hz),1.610-1.681(2H,quint,J=7.2Hz),1.268-1.303(11H,m),0.860-0.952(9H,m)ppm.

[0078] ESI-MS(positive) m / z 272.2[M+H] + , 294.1[M+Na] +

[0079] Production Example 9: Production of N-octanoylglycine ethyl ester (C8Gly-Et)

[0080] [ka]

[0081] N-octanoylglycine (C8Gly, 28.18 g, 0.14 mol) was used as the N-acyl amino acid, and ethanol (320 mL, 5.48 mol) was used as the alcohol, and the reaction was carried out according to the synthesis method of Production Example A to obtain C8Gly-Et (yield 96%).

[0082] ESI-MS(positive) m / z 230.2[M+H] + , 252.1[M+Na] +

[0083] Production Example 10: Production of N-octanoylisoleucine ethyl ester (C8Ile-Et)

[0084] [ka]

[0085] N-octanoylisoleucine (C8Ile, 36.03 g, 0.14 mol) was used as the N-acyl amino acid, and ethanol (320 mL, 5.48 mol) was used as the alcohol, and reacted according to the synthesis method of Production Example A to obtain C8Ile-Et (yield 97%).

[0086] ESI-MS(positive) m / z 286.2[M+H] + ,308.2[M+Na] +

[0087] Production Example 11: Production of N-octanoyl leucine ethyl ester (C8Leu-Et)

[0088] [ka]

[0089] N-octanoylleucine (C8Leu, 36.03 g, 0.14 mol) was used as the N-acyl amino acid, and ethanol (320 mL, 5.48 mol) was used as the alcohol, and the reaction was carried out according to the synthesis method of Production Example A to obtain C8Gly-Et (yield 98%).

[0090] ESI-MS(positive) m / z 286.2[M+H] + ,308.2[M+Na] +

[0091] Production Example 12: Production of N-lauroylisoleucine ethyl ester (C12Ile-Et)

[0092] [ka]

[0093] N-lauroylisoleucine (C12Ile, 43.89 g, 0.14 mol) was used as the N-acyl amino acid, and ethanol (320 mL, 5.48 mol) was used as the alcohol, and reacted according to the synthesis method of Production Example A to obtain C12Ile-Et (yield 91%).

[0094] ESI-MS(positive) m / z 342.3[M+H] + , 364.3[M+Na] +

[0095] Production Example 13: Production of N-lauroylleucine ethyl ester (C12Leu-Et)

[0096] [ka]

[0097] N-lauroylleucine (C12Leu, 43.89 g, 0.14 mol) was used as the N-acyl amino acid, and ethanol (320 mL, 5.48 mol) was used as the alcohol, and reacted according to the synthesis method of Production Example A to obtain C12Leu-Et (yield 88%).

[0098] ESI-MS(positive) m / z 342.3[M+H] + , 364.3[M+Na] +

[0099] Production Example 14: Production of N-lauroyl valine ethyl ester (C12Val-Et)

[0100] [ka]

[0101] N-lauroylvaline (C12Val, 41.92 g, 0.14 mol) was used as the N-acyl amino acid, and ethanol (320 mL, 5.48 mol) was used as the alcohol. The reaction was carried out for 8 hours according to the synthesis method of Production Example A to obtain C12Val-Et (yield 87%).

[0102] ESI-MS(positive) m / z 328.3[M+H] + , 350.2[M+Na] +

[0103] Production Example 15: Production of N-decanoyl valine isopropyl ester (C10Val-iPA)

[0104] [ka]

[0105] N-decanoylvaline (C10Val, 38 g, 0.14 mol) was used as the N-acyl amino acid, and isopropyl alcohol (418 mL, 5.48 mol) was used as the alcohol. The reaction was carried out according to the synthesis method of Production Example A to obtain C10Val-iPA (yield 98%).

[0106] ESI-MS(positive)m / z 314.5[M+H] + ,336.4[M+Na] +

[0107] Production Example 16: Production of N-decanoylalanine isopropyl ester (C10Ala-iPA)

[0108] [ka]

[0109] N-decanoylalanine (C10Ala, 34.6 g, 0.14 mol) was used as the N-acyl amino acid, and isopropyl alcohol (418 mL, 5.48 mol) was used as the alcohol. The reaction was carried out according to the synthesis method of Production Example A to obtain C10Ala-iPA (yield 97%).

[0110] ESI-MS(positive)m / z 285.4[M+H] + ,307.4[M+Na] +

[0111] Production Example 17: Production of N-decanoyl leucine isopropyl ester (C10Leu-iPA)

[0112] [ka]

[0113] N-decanoylleucine (C10Leu, 39.9 g, 0.14 mol) was used as the N-acyl amino acid, and isopropyl alcohol (418 mL, 5.48 mol) was used as the alcohol. The reaction was carried out according to the synthesis method of Production Example A to obtain C10Leu-iPA (yield 97%).

[0114] ESI-MS(positive)m / z 328.5[M+H] + , 350.3[M+Na] +

[0115] Production Example 18: Production of N-hexanoyl valine ethyl ester (C6Val-Et)

[0116] [ka]

[0117] N-hexanoylvaline (C6Val, 30.14 g, 0.14 mol) was used as the N-acyl amino acid, and ethanol (320 mL, 5.48 mol) was used as the alcohol. The reaction was carried out for 8 hours according to the synthesis method of Production Example A to obtain C6Val-Et (yield 82%).

[0118] ESI-MS(positive) m / z 244.3[M+H] + , 266.2[M+Na] +

[0119] Reference Production Examples 1 to 3: Production of N-lauryl valine isopropyl ester (C12 Val-iPA), N-lauryl alanine isopropyl ester (C12 Ala-iPA), and N-lauryl alanine ethyl ester (C12 Ala-Et) N-lauryl valine isopropyl ester (C12 Val-iPA), N-lauryl alanine isopropyl ester (C12 Ala-iPA), and N-lauryl alanine ethyl ester (C12 Ala-Et) were produced according to the description in JP-A-11-240828.

[0120] Example 1: Evaluation of acyl neutral amino acid esters (1) Evaluation of compatibility with hydrophobic organic solvents (oil) 1 g of each sample was weighed out, added to 5 g of liquid paraffin, and mixed by stirring for 10 minutes at 25° C. After stopping the stirring, the mixture was left to stand for 10 minutes at 25° C., and the state of separation of each sample and liquid paraffin was visually confirmed and evaluated according to the following criteria. Very good (A): No separation was observed and the solution was clear. Favorable (B): Almost no separation is observed and the solution is transparent Not very good (C): Localized separation and turbidity occurred. Not at all desirable: (D): Clear separation occurred

[0121] (2) Evaluation of compatibility with hydrophilic organic solvents 0.5 g of each sample was weighed out, added to 10 g of 1,3-butylene glycol, and mixed by stirring for 10 minutes at 25° C. After stopping the stirring, the mixture was left to stand for 10 minutes at 25° C., and the state of separation of each sample and 1,3-butylene glycol was visually confirmed and evaluated according to the following criteria. Very good (A): No separation was observed and the solution was clear. Favorable (B): Almost no separation is observed and the solution is transparent Not very good (C): Localized separation and turbidity occurred. Not at all desirable: (D): Clear separation occurred

[0122] (3) Property evaluation Each compound was cooled to 4° C. for one day, and then left at room temperature (25° C.) for three days. After three days, the properties of each compound were confirmed at room temperature (25° C.). Preferred (A): The property is liquid at room temperature (25°C). Therefore, it is easy to prepare a formulation by simply mixing with other liquid ingredients at room temperature without heating. Unfavorable (B): The substance is solid or crystalline at room temperature (25°C), making it difficult to prepare a formulation by simply mixing it with other liquid ingredients at room temperature without heating.

[0123] (4) Evaluation of emollient properties Next, emollient properties were evaluated. The backs of the hands of five expert panelists were washed with soap and then dried, and 200 mg of each evaluation sample was added to the hands and spread evenly over the skin. After drying for 15 minutes at 25°C, the addition of each sample was evaluated according to the following criteria to see whether the skin's dryness was improved and the skin was smoothed, and whether moisturizing properties were improved. Based on the panelists' average evaluation scores, the emollient properties during use were evaluated as follows:

[0124] <Evaluation of emollient properties during use> 3 points: Skin was very well conditioned and moisturizing was improved significantly 2 points: Skin was smoothed and moisturizing was improved 1 point: My skin was not well conditioned and I didn't feel much improvement in moisturizing properties. 0 points: My skin was not conditioned at all and I didn't feel any improvement in moisturizing.

[0125] The average score of the expert panelists was 2.4 or above is A, 1.5 or more but less than 2.4 is B, 0.5 or more but less than 1.5 is C, Less than 0.5 is D It was decided.

[0126] [Table 1]

[0127] As a result, the acyl neutral amino acid ester could be stably blended with hydrophobic organic solvents (oils) and hydrophilic organic solvents (Table 1). Therefore, it was demonstrated that the acyl neutral amino acid ester is an excellent oil agent. The acyl neutral amino acid ester also facilitated the preparation of the formulation (Table 1). Thus, the acyl neutral amino acid ester was shown to have excellent handling properties. The acyl neutral amino acid ester also had excellent emollient properties (Table 1). Therefore, it was shown that the acyl neutral amino acid ester can improve the retention of moisture in the stratum corneum from outside the stratum corneum through its emollient action (Table 1).

[0128] Example 2: Evaluation of esterase-catalyzed hydrolysis of acyl neutral amino acid esters 5mg of acyl neutral amino acid ester was added to 1xPBS buffer, and 2.15μl (0.2wt%) of Triton-X100 (Aldrich) was added, and then the mixture was mixed uniformly by ultrasonic irradiation. A buffer solution of esterase (Esterase from porcine liver, Sigma-Aldrich) was added to the mixture so that 5 units of esterase were added per molecule of acyl amino acid, and the mixture was mixed by stirring. This mixture was shaken and stirred for 24 hours in a shaker heated to 30℃ to react. The reaction product was centrifuged in a centrifuge at 12000xg, and the supernatant was analyzed by high performance liquid chromatography (Shimadzu). As a control, only buffer was added instead of the esterase solution. The esterase used (Esterase from porcine liver) was used as a model for the esterase enzyme present in human skin [Bonina, FP et al., Eur. J. Pharm. Sci. 14, 123-134 (2001); Wong, O. et al., Int. J. Pharm., 52, 191-202 (1989); Vavrova K. et al., J. Control Release. 104, 41-49 (2005)].

[0129] When the ester bond of the acyl neutral amino acid ester is hydrolyzed by esterase, the peak area of ​​the acyl neutral amino acid ester decreases on the HPLC chromatogram, and a new peak is observed at the same elution time as the acyl neutral amino acid. The appearance of this peak indicates that the acyl neutral amino acid ester has been hydrolyzed by esterase to produce the acyl neutral amino acid.

[0130] As test substances, the compounds produced in Production Examples 1 to 18 and Reference Production Examples 1 to 3 were used.

[0131] In the presence of esterase, C6Val-iPA, C8Ala-iPA, C8Val-iPA, C8Gly-iPA, C8Ile-iPA, C8Leu-iPA, C8Ala-Et, C8Val-Et, C8Gly-Et, C8Ile-Et, C8Leu-Et, C12Ile-Et, C10Ala-iPA, C10Val-iPA, C10Leu-iPA, C1 All of 2Ala-Et, C12Ala-iPA, C12Val-Et, C12Val-iPA, C12Ile-iPA, and C12Leu-Et were hydrolyzed to produce C6Val, C8Ala, C8Val, C8Gly, C8Ile, C8Leu, C10Ala, C10Val, C10Leu, C12Ala, C12Val, C12Ile, and C12Leu.

[0132] Examples 3 to 7 and Comparative Examples 2 to 3: Comparison of the amount of amplification of genes such as moisturizing-related proteins by octanoyl neutral amino acid Human normal epidermal keratinocytes (NHEK) (NB) (Kurabo) were precultured in HuMedia-KG2 (Kurabo) and cultured at 30 x 10 4 Adjust the concentration of cells / mL and add 2 mL of the adjusted culture medium (i.e., 60x10 4 Cells / well) were added to a 6-well plate and cultured at 37°C for 1 day. Samples (octanoyl valine (Example 3: C8Val), octanoyl alanine (Example 4: C8Ala), octanoyl leucine (Example 5: C8Leu), octanoyl isoleucine (Example 6: C8Ile), octanoyl glycine (Example 7: C8Gly), glycyl proline (Comparative Example 2: Gly-Pro), and valine (Comparative Example 3: Val)) were added to the concentrations shown in each figure and reacted for 48 hours. After the reaction, total RNA was extracted from the cells, reverse transcribed, and the amplification amount of the target genes (filaggrin, involucrin, transglutaminase (TG) 1, keratin 10, and loricrin) was measured by real-time PCR (n=2), and compared with the amplification amount of the control (no addition). GAPDH was used as a correction gene. The calculation was performed using the comparative CT method, the primers and probes were TaqMan (registered trademark) Gene Expression, and the fluorescent dye was FAM. The results are shown in Figures 1 and 2.

[0133] 1 and 2, the amplification amount of each target gene in Examples 3 to 7 was higher than that in Comparative Examples 2 and 3. These results indicate that acyl neutral amino acids can promote the production of moisturizing-related proteins.

[0134] Examples 8 to 13: Comparison of amplification amounts of genes for moisturizing-related proteins, etc. by acyl valine The same procedure as in Example 3 was carried out except that butanoyl valine (Example 8: C4Val), hexanoyl valine (Example 9: C6Val), octanoyl valine (Example 10: C8Val), decanoyl valine (Example 11: C10Val), lauroyl valine (Example 12: C12Val) and acetyl valine (Example 13: C2Val) were used as samples and that filaggrin, involucrin and transglutaminase (TG) 1 were used as target genes. The results are shown in FIG.

[0135] As is clear from Figure 3, the amount of amplification of each target gene was higher than that of the control in all of Examples 8 to 13. These results indicate that an acyl neutral amino acid having an acyl group with 2 to 12 carbon atoms or a salt thereof can promote the production of moisturizing-related proteins regardless of the type of acyl group.

[0136] Examples 14 to 24: Comparison of the amount of filaggrin gene amplification by acylvline or acylalanine Human normal epidermal keratinocytes (NHEK (NB)) (Kurabo Industries, Ltd.) were precultured in HuMedia-KG2 (Kurabo Industries, Ltd.) and cultured at 15 x 10 4 Adjust the concentration of cells / mL and add 2 mL of the adjusted culture medium (i.e., 30x10 4Cells / well) were added to a 6-well plate and cultured for 1 day at 37° C. Samples (lauroyl valine (Example 14: C12Val), decanoyl valine (Example 15: C10Val), octanoyl valine (Example 16: C8Val), hexanoyl valine (Example 17: C6Val), butanoyl valine (Example 18: C4Val), acetyl valine (Example 19: C2Val), lauroyl alanine (Example 20: C12Ala), decanoyl alanine (Example 21: C10Ala), octanoyl alanine (Example 22: C8Ala), hexanoyl alanine (Example 23: C6Ala), butanoyl alanine (Example 24: C4Ala)) were added to the concentrations shown in each figure and reacted for 24 hours. After the reaction, total RNA was extracted from the cells, reverse transcribed, and the amount of amplification of the target gene (filaggrin) was measured by real-time PCR (n=2). The amount of amplification of the control (no addition) was set to 100% and compared with this value. GAPDH was used as a correction gene. Calculation was performed using the comparative CT method, the primers and probes were TaqMan (registered trademark) Gene Expression, and the fluorescent dye was FAM.

[0137] The following evaluations were performed according to the amount of amplification. The results are shown in Tables 2 to 3 and Figures 4 to 5. Very favorable (A): 200% or more Preferred (B): 100% or more but less than 200% Not very favorable (C): 50% or more but less than 100% Not at all favorable (D): Less than 50%

[0138] [Table 2]

[0139] [Table 3]

[0140] Considering the results of Examples 2 to 24 (Tables 2, 3, Figures 1 to 5, and 7, 8), it is believed that the acyl neutral amino acid ester can improve the expression promoting effect of moisturizing-related proteins such as filaggrin, and therefore can improve the moisturizing ability of retaining moisture inside the stratum corneum. In addition, it is believed that the acyl neutral amino acid ester can improve the expression promoting effect of proteins related to the barrier function of the skin, and therefore can improve the barrier function that suppresses the intrusion of foreign substances. In addition, considering the results of Example 1 (Table 1) in addition to these results, it is believed that the acyl neutral amino acid ester has excellent handling properties and can fully improve the stratum corneum function by both its action inside the stratum corneum and its emollient action from the outside of the stratum corneum.

[0141] Examples 25-29: Evaluation of cytotoxicity Human normal epidermal keratinocytes (NHEK (NB)) (Kurabo Industries, Ltd.) were precultured in HuMedia-KG2 (Kurabo Industries, Ltd.) and cultured at 15 x 10 4 Adjust the concentration of cells / mL and add 2 mL of the adjusted culture medium (i.e., 30x10 4 Cells / well) were added to a 6-well plate and cultured at 37°C for one day. Samples (lauroyl valine (Comparative Example 4: C12Val), decanoyl valine (Example 25: C10Val), octanoyl valine (Example 26: C8Val), hexanoyl valine (Example 27: C6Val), butanoyl valine (Example 28: C4Val), acetyl valine (Example 29: C2Val) were added to the concentrations shown in each figure and reacted for 24 hours. Thereafter, the medium was discarded and replaced with 2 mL / well of Neutral Red solution, and cultured for another 2 hours. The Neutral Red solution used was Neutral Red (Kurabo) diluted 1 / 100 with a mixture of HuMedia-KG2 medium / physiological saline (2:1). Neutral The cells stained with Red solution were washed once with PBS(-), then fixed with 1% CaCl2 / 1% formalin solution (1.5 mL / well) for 1 minute, and extracted with 1% acetic acid / 50% ethanol solution (1.5 mL / well) at room temperature for 20 minutes. The absorbance at 540 / 630 nm was measured using a plate reader.

[0142] The following evaluations were performed according to the cell viability, and the results are shown in Table 4 and FIG. Very favorable (A): 95% or more Preferred (B): 75% or more but less than 95% Not very favorable (C): 50% or more but less than 75% Not at all favorable (D): Less than 50%

[0143] [Table 4]

[0144] The results of Examples 14 to 24 show that each acyl neutral amino acid can amplify the filaggrin gene. Moreover, the results of Examples 25 to 29 and Comparative Example 4 show that each acyl neutral amino acid and acyl neutral amino acid ester of Examples 25 to 29 have low cytotoxicity, whereas the acyl neutral amino acid of Comparative Example 4 has high cytotoxicity.

[0145] Example 30: Improvement of profilaggrin production rate by octanoylvaline (C8Val) First, human normal epidermal keratinocytes NHEK (NB) (Kurabo Industries, Ltd.) were cultured in HuMedia-KG2 (Kurabo Industries, Ltd.) at 37°C under 5% CO2 and saturated water vapor. The confluent cells were cultured in a 6-well plate at 15 × 10 4After culturing at 37°C for 1 day, the medium was replaced with HuMedia-KG2 medium supplemented with 100μM octaenoyl valine (C8Val) and 1.3mM CaCl2, and the medium was replaced every 1-2 days for 6 days. After culturing, the medium was removed, the cells were washed twice with cold PBS(-), and 200μL / well of extract (M-PER (Thermo Fisher Scientific)) supplemented with protease inhibitor and phosphatase inhibitor (EzRIPA Lysis (ATTO)) was added to each well, and the cells were shaken at 200 rpm for 5 minutes in a shaker (TAITEC). The cells were scraped off with a scraper, and 200 μL of a denaturant (EzApply (ATTO)) was added to the entire liquid including the precipitate, and then the mixture was heated and shaken at 1100 rpm and 100° C. for 5 minutes in a shaker (Bioer Technology). The resulting solution was centrifuged at 10,000 G in a centrifuge (Tomy Seiko) at 4° C. for 10 minutes, and the supernatant was used as a sample for Western blotting.

[0146] Next, 20 μL of each Western blot sample (profilaggrin) or 5 μL of a solution obtained by diluting the Western blot sample prepared in (1) 50 times (GAPDH) per gel lane was applied to e-PAGEL 7.5% (ATTO) and electrophoresed for 1 hour at a constant current of 21 mA in an electrophoresis device (ATTO). After electrophoresis, the gel was transferred to a PVDF membrane, washed with TBS-T (ATTO), and blocked with EzBlock BSA (ATTO). Next, an antigen-antibody reaction was performed with a primary antibody solution (Anti Filaggrin (AKH1) antibody (Santa Cruz Biotechnology) (profilaggrin), Anti GAPDH (6C5) antibody (Santa Cruz Biotechnology) (GAPDH)). The cells were labeled with a secondary antibody (Anti-IgG (H+L), Mouse, Goat-poly, HRP (KPL)), and the band intensities (250-400 kDa (profilaggrin), 37 kDa (GAPDH)) were quantified using an image analyzer (Amersham) by chemiluminescence (n=2). The expression level of profilaggrin was normalized by the expression level of GAPDH, and the production level of the control (no octaenoylvaline (C8Val) added) was set at 100% for comparison.

[0147] The results obtained were evaluated as follows and are shown in Table 5. Very favorable (A): 250% or more Preferred (B): 150% or more but less than 250% Not very favorable (C): 100% or more but less than 150% Not at all desirable (D): Less than 100%

[0148] [Table 5]

[0149] From the above, it was revealed that octanoylvaline (C8Val) improves the production of profilaggrin protein.

[0150] Example 31: Evaluation of partition coefficients of acyl neutral amino acid esters The partition coefficient (LogP) of the acyl neutral amino acid ester was calculated using a chemical structural formula calculation software called ChemSketch (Advanced Chemistry Development, Inc., (ACD / Labs)).

[0151] [Table 6]

[0152] From Table 6, it can be seen that the LogP values ​​of acyl neutral amino acid esters such as C6Ala-iPA, C6Val-Et, and C6Ile-Et are in the range of 1 to 4, and have excellent properties for transdermal absorption (Marc Schneider, M. et al., Dermatoendocrinol., 1, 197-206 (2009)). [Industrial Applicability]

[0153] The compounds of the present invention are useful as keratinocyte function improving agents, moisturizing agents, etc., and for the development of cosmetics, pharmaceuticals, quasi-drugs, and other products.

Claims

1. A skin topical preparation comprising a compound selected from the following (I) to (IV) and an organic solvent: (I) N-octanoylisoleucine isopropyl ester, and N-octanoylisoleucine ethyl ester; (II) N-octanoyl leucine ethyl ester; (III) N-octanoylalanine isopropyl ester (excluding those contained in N-cocoylalanine isopropyl ester), and N-decanoylalanine isopropyl ester (excluding those contained in N-cocoylalanine isopropyl ester); and (IV) N-hexanoyl valine ethyl ester, N-octanoyl valine ethyl ester, and N-decanoyl valine isopropyl ester.

2. The skin topical preparation according to claim 1, wherein the compound is a compound selected from (I).

3. The skin topical preparation according to claim 1, wherein the compound is the compound (II).

4. The skin topical preparation according to claim 1, wherein the compound is a compound selected from the group consisting of (III).

5. The skin topical preparation according to claim 1, wherein the compound is a compound selected from (IV).

6. A cosmetic composition comprising a compound selected from the following (I) to (IV) and an organic solvent: (I) N-octanoylisoleucine isopropyl ester, and N-octanoylisoleucine ethyl ester; (II) N-octanoyl leucine ethyl ester; (III) N-octanoylalanine isopropyl ester (excluding those contained in N-cocoylalanine isopropyl ester), and N-decanoylalanine isopropyl ester (excluding those contained in N-cocoylalanine isopropyl ester); and (IV) N-hexanoyl valine ethyl ester, N-octanoyl valine ethyl ester, and N-decanoyl valine isopropyl ester.

7. The cosmetic preparation according to claim 6, wherein the compound is a compound selected from (I).

8. The cosmetic preparation according to claim 6, wherein the compound is the compound (II).

9. The cosmetic preparation according to claim 6, wherein the compound is a compound selected from the group (III).

10. The cosmetic preparation according to claim 6, wherein the compound is a compound selected from the group (IV).

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