COMPOSITION FOR TREATING ATOPY OR PRURITUS COMPRISING N-ACETYL OR N-ACYL AMINO ACID

Abstract

The present disclosure relates to a composition for preventing, alleviating or treating pruritus and/or atopy using an N-acetylamino acid or an N-acylamino acid having almost no side effects on the human body. Also, the present disclosure relates to a cosmetic composition for moisturizing skin or soothing skin. The composition of the present disclosure may be utilized to ameliorate a problematic skin condition caused by various causes, or to safely and effectively alleviate or treat pruritus and/or atopy without concern about side effects.

Claims

1. A method for preventing or treating atopy or pruritus, comprising administering a composition to a subject in need thereof, wherein said composition comprises an N-acylamino acid selected from the group consisting of N-acetylalanine, N-acetylthreonine, N-acetylarginine, N-acetyltryptophan, N-propionyltryptophan, N-butyryltryptophan, N-pentanoyltryptophan, N-undecanoyltryptophan, N-palmitoyltryptophan, N-docos-13-enoyltryptophan, N-stearyltryptophan, N-oleoyltryptophan, N-acetyl-γ-glutammylalanine, and N-palmitoylalanine; or a pharmaceutically acceptable salt thereof as an active ingredient.

2. The method according to claim 1, wherein the N-acylamino acid is one or more amino acids selected from the group consisting of N-acetylalanine, N-acetylthreonine, N-acetylarginine, and N-acetyltryptophan.

3. The method according to claim 2, wherein the N-acylamino acid is selected from the group consisting of N-acetyl-L-alanine, N-acetyl-L-threonine, N-acetyl-L-arginine, and N-acetyl-L-tryptophan.

4. The method according to claim 1, wherein the N-acylamino acid is selected from the group consisting of N-propionyl-L-tryptophan, N-butyryl-L-tryptophan, N-pentanoyl-L-tryptophan, N-undecanoyl-L-tryptophan, N-palmitoyl-L-tryptophan, N-docos-13-enoyl-L-tryptophan, N-stearyl-L-tryptophan, N-oleoyl-L-tryptophan, N-acetyl-γ-glutammyl-L-alanine, and N-palmitoyl-L-alanine.

5. The method according to claim 1, wherein the pruritus is selected from the group consisting of vulvar pruritus, vaginal pruritus, paroxysmal pruritus, winter pruritus, anal pruritus, scrotal pruritus, aquagenic pruritus, scalp pruritus, nasal pruritus, oral pruritus, and ocular pruritus.

6. The method according to claim 1, wherein the composition is prepared into a formulation selected from the group consisting of a formulation for external application to skin, an aerosol, a spray, a collyrium, an oral medication, and an injection.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0091] FIG. 1A shows a process of inducing atopic dermatitis-like skin lesions by repeatedly applying 2,4-dinitrofluorobenzene (DNFB) to Balb/c mouse and administering a drug.

[0092] FIG. 1B shows a process of inducing atopic dermatitis lesions by repeatedly applying 2,4-dinitrofluorobenzene (DNFB) to Nc/Nga mouse and administering a drug.

[0093] FIG. 2A shows a result of applying 20 N-acetyl-L-amino acids on the dermatitis-induced area of atopic dermatitis-induced Balb/c mouse and then measuring clinical skin scores (SCORAD) (*P<0.05 versus 2,4-dinitrofluorobenzene (DNFB)-treated group).

[0094] FIG. 2B shows the images of the back skin of Balb/c mouse treated with 2,4-dinitrofluorobenzene (DNFB) to induce atopic dermatitis and then treated for 7 days with a control substance, N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-threonine, N-acetyl-L-arginine or N-acetyl-L-tryptophan on day 29.

[0095] FIG. 3A shows a result of applying N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-threonine, N-acetyl-L-arginine or N-acetyl-L-tryptophan on the dermatitis-induced area of atopic dermatitis-induced Nc/Nga mouse and then measuring clinical skin scores (SCORAD) (*P<0.05 versus 2,4-dinitrofluorobenzene (DNFB)-treated group).

[0096] FIG. 3B shows the images of the back skin of Nc/Nga mouse treated with 2,4-dinitrofluorobenzene (DNFB) to induce atopic dermatitis and then treated for 7 days with a control substance, N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-threonine, N-acetyl-L-arginine or N-acetyl-L-tryptophan on day 22.

[0097] FIG. 3C shows a result of treating Nc/Nga mouse with 2,4-dinitrofluorobenzene (DNFB) to induce atopic dermatitis, treating for 7 days with a control substance, N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-threonine, N-acetyl-L-arginine or N-acetyl-L-tryptophan on day 22, and then staining the back skin tissue sliced to a thickness of 5 μm with hematoxylin/eosin.

[0098] FIG. 4A shows a result of treating Balb/c mouse with 2,4-dinitrofluorobenzene (DNFB) to induce atopic dermatitis, treating for 7 days with a control substance, N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-threonine, N-acetyl-L-arginine or N-acetyl-L-tryptophan on day 29, and then measuring the total IgE level in the serum sample of the mouse by ELISA (*P<0.05 versus 2,4-dinitrofluorobenzene (DNFB)).

[0099] FIG. 4B shows a result of treating Nc/Nga mouse with 2,4-dinitrofluorobenzene (DNFB) to induce atopic dermatitis, treating for 7 days with a control substance, N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-threonine, N-acetyl-L-arginine or N-acetyl-L-tryptophan on day 29, and then measuring the total IgE level in the serum sample of the mouse by ELISA (*P<0.05 versus 2,4-dinitrofluorobenzene (DNFB)).

[0100] FIG. 5A shows a result of treating Balb/c mouse with 2,4-dinitrofluorobenzene (DNFB) to induce atopic dermatitis, treating for 7 days with a control substance, N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-threonine, N-acetyl-L-arginine or N-acetyl-L-tryptophan on day 29, and then measuring the quantity of IL4 and interferon γ mRNAs in the skin tissue of the mouse (*P<0.05 versus 2,4-dinitrofluorobenzene (DNFB)).

[0101] FIG. 5B shows a result of treating Nc/Nga mouse with 2,4-dinitrofluorobenzene (DNFB) to induce atopic dermatitis, treating for 7 days with a control substance, N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-threonine, N-acetyl-L-arginine or N-acetyl-L-tryptophan on day 29, and then measuring the quantity of IL4 and interferon γ mRNAs in the skin tissue of the mouse (*P<0.05 versus 2,4-dinitrofluorobenzene (DNFB)).

[0102] FIG. 6 shows a result of comparing the atopic dermatitis-relieving effect of L-form N-acetylalanine and N-acetyltryptophan with D/L-form and D-form N-acetylalanine and N-acetyltryptophan at a concentration of 0.1% in Nc/Nga mouse in which atopic dermatitis is induced with DNFB (*P<0.05 versus 2,4-dinitrofluorobenzene (DNFB)).

[0103] FIG. 7 shows a result of comparing the pruritus-relieving effect of L-form N-acetylalanine, N-acetylthreonine, N-acetylarginine and N-acetyltryptophan with D/L-form and D-form N-acetylalanine and N-acetyltryptophan at a concentration of 0.1% in Nc/Nga mouse in which atopic dermatitis is induced with DNFB (*P<0.05 versus 2,4-dinitrofluorobenzene (DNFB)).

[0104] FIG. 8 shows a result of applying N-acyl-L-tryptophan, N-acetyl-γ-glutammylalanine and N-palmitoyl-L-alanine onto the dermatitis-induced area of atopic dermatitis-induced Nc/Nga mouse and then measuring clinical skin score (SCORAD) (*P<0.05 versus 2,4-dinitrofluorobenzene (DNFB)-treated group).

[0105] FIG. 9 shows MS data of compound N-Acetyl-γ-glutammylalanine was synthesized by Genescript (USA).

BEST MODE FOR CARRYING OUT INVENTION

[0106] Hereinafter, the present disclosure will be described in detail through examples. However, the following examples are for illustrative purposes only and it will be obvious to those of ordinary skill in the art that the scope of the present disclosure is not limited by the examples.

EXAMPLES

<Example 1> Test Animals and Reagents

[0107] 7-week-old male Balb/c mice and 7-week-old male Nc/Nga mice were purchased from Orient Bio (Seongnam, Gyeonggi-do, Korea) and maintained under specific pathogen-free conditions. The mice were housed in an air-conditioned animal room at a temperature of 25±1° C. and a relative humidity of 40±5%, and they were given distilled water and laboratory diet. Animal treatment and maintenance complied with the Principles of Laboratory Animal Care (NIH Publication No. 85-23, revised in 1985) and the guidelines of the Institutional Animal Care and Use Committee of the Jeonbuk National University (KHUASP (SE)-15-021). All procedures were conducted in accordance with the guidelines of the United States National Institute of Health (NIH).

<Example 2> Induction of Atopic Dermatitis

[0108] In order to induce atopy-like dermatitis in Balb/c mice, DNFB sensitization was induced by applying 100 μL of 0.35% 2,4-dinitrofluorobenzene (DNFB) (Sigma, USA) in acetone/olive oil (3:1) on the shaved back skin of the mice. Then, dermatitis was induced by applying 100 μL of 0.25% DNFB on days 6, 9, 12, 15, 18 21, 24 and 27 on the shaved back skin. Control mice were treated with a vehicle of the same volume (FIG. 1A).

[0109] In order to establish a model more similar to an atopy model than that of the Balb/c mice, atopy was induced in Nc/Nga mouse mice. Specifically, after inducing DNFB sensitization by applying 100 μL of 0.35% 2,4-dinitrofluorobenzene (DNFB) in acetone/olive oil (3:1) on the shaved back skin, dermatitis was induced by applying 100 μL of 0.15% DNFB for 4-20 days, every other day. Control mice were treated with a vehicle of the same volume (FIG. 1B).

<Example 3> Drug Treatment

[0110] After dissolving an N-acetyl or N-acylamino acid in phosphate-buffered saline to 0.1%, 200 μL of the solution was applied on the back skin of the mice every day, from day 22 until day 28 for the Balb/c atopic dermatitis model, and from day 15 until day 21 for the Nc/Nga atopic dermatitis model. When the N-acetyl or N-acylamino acid was treated together with DNFB, they were treated with 12-hour intervals in order to avoid direct reaction between the DNFB and the N-acetyl or N-acylamino acid. A non-treated group and a 2,4-dinitrofluorobenzene (DNFB) group were treated with phosphate-buffered saline of the same volume (FIGS. 1A-1B). As the N-acetylamino acid, products purchased from Sigma-Aldrich (USA), MP scientific (USA), TCI (Tokyo Chemical Industry, Japan), Santacruz (USA), etc. were used without purification.

<Example 4> Evaluation of Skin-soothing Effect and Severity of Atopic Dermatitis

[0111] The degree of skin soothing and the severity of atopic dermatitis were evaluated macroscopically according to the previously established SCORAD (SCORing Atopic Dermatitis) method (Oranje et al., 2007). The degree of symptoms such as edema, erythema, eschar, dryness, abrasion, lichenification, etc. was graded from 0 to 3 (0, no symptom; 1, mild; 2, moderate; 3, severe). The overall dermatitis score was determined from the sum of all individual scores (Table 1). The assessment was performed by an investigator who was blind to the grouping of the mice. As seen from Table 1, from among the 20 N-acetyl-L-amino acids, N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-arginine, N-acetyl-L-threonine and N-acetyl-L-tryptophan showed significant skin-soothing and atopic dermatitis-treating effects.

TABLE-US-00001 TABLE 1 Mouse 1 Licheni- Mouse 2 Erythema Edema Eschar Dryness Abrasion fication Sum Erythema Edema Eschar Dryness Abrasion Control 0 0 0 0 0 0 0 0 0 0 0 0 DNFB (D) 3 2 2 3 2 3 15 2 3 2 2 3 D + N-acetyl- 2 2 2 2 2 3 13 2 1 2 3 2 L-cysteine D +N-acetyl- 1 1 1 2 1 0 6 1 1 1 0 1 L-alanine D + N-acetyl-L- 3 2 2 3 3 2 152 2 2 3 2 3 asparagine D + N-acetyl- 3 2 1 3 2 2 13 3 2 2 3 2 L-phenylalanme D + N-acetyl- 3 2 2 2 2 2 13 3 2 2 3 2 L-aspartic acid D + N-acetyl- 1 1 1 2 1 1 7 1 1 1 0 1 L-threonine D + N-acetyl- 3 2 2 3 2 2 14 3 2 2 3 2 L-leucine D + N-acetyl- 3 2 2 2 2 2 13 3 2 2 3 2 L-serine D + N-acetyl- 3 2 1 3 2 2 13 2 3 2 3 2 L-proline D + N-acetyl- 1 1 1 0 1 1 5 0 1 1 1 0 L-tryptophan D + N-acetyl- 3 2 3 3 1 3 15 2 2 2 3 2 L-isoleucine D + N-acetyl- 3 2 2 2 2 3 14 2 2 2 3 2 L-glutamic acid D + N-acetyl- 3 2 2 2 2 3 14 3 2 2 3 2 L-glycine D + N-acetyl- 3 2 2 2 2 3 14 2 2 2 2 2 L-valine D + N-acetyl- 1 1 1 1 1 1 6 1 1 1 1 1 L-arginine D + N-acetyl- 3 2 2 3 2 1 13 3 3 2 2 2 L-Lysine D + N-acetyl- 3 2 3 3 2 2 15 3 2 2 3 2 L-tyrosme D +N-acetyl- 2 2 2 2 2 3 13 2 2 2 2 2 L-glutamine D + N-acetyl- 3 2 2 3 2 3 15 3 2 2 3 2 L-histidine D + N-acetyl- 2 2 2 3 2 3 14 3 2 3 3 2 L-methionine Mouse 2 Mouse 3 Licheni- Licheni- fication Sum Erythema Edema Eschar Dryness Abrasion fication Sum Mean Deviation Control 0 0 0 0 0 0 0 0 0 DNFB (D) 3 15 3 3 2 2 3 3 16 15.33 0.58 D + N-acetyl- 3 13 1 2 2 2 2 2 11 12.33 1.15 L-cysteine D +N-acetyl- 0 4 1 1 1 0 1 1 5 5 1 L-alanine D + N-acetyl-L- 3 14 3 3 3 3 2 2 16 15 1 asparagine D + N-acetyl- 3 15 3 2 2 3 1 3 14 14 1 L-phenylalanme D + N-acetyl- 2 14 3 2 2 2 2 1 12 13 1 L-aspartic acid D + N-acetyl- 1 5 1 1 2 1 0 1 6 6 1 L-threonine D + N-acetyl- 3 15 3 2 2 3 2 1 13 14 1 L-leucine D + N-acetyl- 3 15 3 2 2 3 2 2 14 14 1 L-serine D + N-acetyl- 2 14 3 2 2 3 1 2 13 13.33 0.58 L-proline D + N-acetyl- 0 3 0 0 2 0 2 0 4 4 1 L-tryptophan D + N-acetyl- 3 14 3 2 2 3 1 3 14 14.33 0.58 L-isoleucine D + N-acetyl- 2 13 1 2 2 3 2 2 12 13 1 L-glutamic acid D + N-acetyl- 3 15 3 2 2 3 2 3 15 14.67 0.58 L-glycine D + N-acetyl- 3 13 2 2 2 3 1 2 12 13 1 L-valine D + N-acetyl- 1 6 1 1 1 1 0 1 5 5.67 0.58 L-arginine D + N-acetyl- 3 15 3 2 2 3 2 2 14 14 1 L-Lysine D + N-acetyl- 3 15 3 2 2 2 2 2 13 14.33 1.15 L-tyrosme D +N-acetyl- 2 12 2 2 2 2 2 1 11 12 1 L-glutamine D + N-acetyl- 3 15 3 2 2 3 2 2 14 14.67 0.58 L-histidine D + N-acetyl- 3 16 2 2 2 3 2 3 14 14.67 1.15 L-methionine

[0112] Also, as seen from FIG. 2A, from among the 20 N-acetyl-L-amino acids, N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-arginine, N-acetyl-L-threonine and N-acetyl-L-tryptophan showed significant atopic dermatitis-treating effect in the Balb/c atopic dermatitis model (FIG. 2A). The apparent degree of dermatitis was also decreased remarkably in the atopy-induced mice treated with N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-arginine, N-acetyl-L-threonine or N-acetyl-L-tryptophan (FIG. 2B).

[0113] As seen from FIG. 3, from among the N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-arginine, N-acetyl-L-threonine and N-acetyl-L-tryptophan, which exhibited effects in the Balb/c atopic dermatitis model, N-acetyl-L-alanine and N-acetyltryptophan showed atopic dermatitis-treating effect in the atopic dermatitis model of Nc/Nga mice (FIG. 3A). Nc/Nga mice are widely used as an atopic dermatitis model. In particular,

[0114] N-acetyl-L-alanine and N-acetyltryptophan showed remarkable effect in this model (FIG. 3B). After extracting back skin tissues of the atopic dermatitis-induced and drug-treated Nc/Nga mice of Example 2, the tissues were fixed with an Accustain formalin-free fixative solution and then prepared into paraffin blocks. The paraffin blocks were sliced to a thickness of 5 μm and the change in the thickness of the epidermal and dermal layers was observed by staining with hematoxylin/eosin. The thickness of the epidermal and dermal layers, which was increased by the induction of atopic dermatitis, was significantly decreased by the treatment with N-acetyl-L-alanine or N-acetyl-L-tryptophan (FIG. 3C).

<Example 5> Measurement of Serum IqE Level

[0115] After treatment with the test substance, the mice were sacrificed and blood was taken from the heart. After isolating serum from the blood, IgE level was measured. Specifically, after attaching antibodies diluted in a buffer solution onto a 96-well plate and incubating overnight at 4° C., experiment was conducted using an IgE ELISA kit (BD Biosciences, San Diego, Calif.) according to the provided manual. The quantity of the IgE protein was determined by measuring absorbance at 450 nm using a microplate reader. As seen from FIGS. 4A-4B, the treatment of the atopy-induced Balb/c mice with N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-arginine, N-acetyl-L-threonine and N-acetyl-L-tryptophan resulted in significant decrease in serum IgE level (FIG. 4A), and the treatment of the atopy-induced Nc/Nga mice with N-acetyl-L-alanine and N-acetyl-L-tryptophan resulted in significant decrease in serum IgE level (FIG. 4B). Because the serum IgE level is indicative of the severity of atopic dermatitis, the result of FIGS. 4A-4B shows that N-acetyl-L-alanine, N-acetyl-L-arginine, N-acetyl-L-threonine and N-acetyl-L-tryptophan have atopic dermatitis-treating effect.

<Example 6> Measurement of IL4 and Interferon γ by Quantitative Real-time PCR

[0116] After isolating total RNA from the atopy-induced skin tissue using 500 μL of Trizol (Life Technologies, USA) according to the manufacturer's protocol and synthesizing cDNA using the Superscript III reverse transcriptase (Life Technologies, USA), real-time PCR was conducted by reacting with the primers of IL4 and interferon γ to be analyzed. The real-time PCR was conducted on a StepOne Plus PCR cycler (Applied Biosystems) using SYBR Green (Applied Biosystems, Foster City, Calif.). The mRNA expression data were analyzed by the ΔΔCT method and were normalized to β-actin for gene detection. The primers necessary for the real-time PCR were purchased from Qiagen (USA). As seen from FIGS. 5A-5B, the treatment of the atopy-induced Balb/c mice with N-acetyl-L-cysteine, N-acetyl-L-alanine, N-acetyl-L-arginine, N-acetyl-L-threonine and N-acetyl-L-tryptophan significantly decreased the level of IL4 and interferon γ in the skin tissue (FIG. 5A), and the treatment of the atopy-induced Nc/Nga mice with N-acetyl-L-alanine and N-acetyl-L-tryptophan significantly decreased the level of IL4 and interferon γ in the skin tissue. IL4 is known to induce TH2 response and interferon γ is known to induce TH1 response. Accordingly, the result of FIGS. 5A-5B shows that N-acetyl-L-alanine, N-acetyl-L-arginine, N-acetyl-L-threonine and N-acetyl-L-tryptophan exhibit therapeutic effects by inhibiting TH2 and TH1 responses activated by atopic dermatitis.

<Example 7> Stereo-specificity of N-acetylamino Acid

[0117] In order to investigate the effect of L-form, L/D-form and D-form N-acetylalanine and N-acetyltryptophan on atopic dermatitis, their dermatitis-treating effect was evaluated for the atopic dermatitis model of Nc/Nga mice. As a result, the LID-form and D-form N-acetylalanine and N-acetyltryptophan had no effect and only the L-form showed remarkable effect (FIG. 6). This shows that the pruritus-inhibiting action by these substances is stereo-specific.

<Example 8> Pruritus Inhibition Test

[0118] In order to investigate whether L-form, LID-form and D-form N-acetylalanine, N-acetylarginine, N-acetylthreonine and N-acetyltryptophan inhibit pruritus caused by atopic contact dermatitis, 20 μL of 0.1% 2,4-dinitrofluorobenzene (DNFB) solution and 0.1% N-acetylamino acid dissolved in physiological saline were applied once onto the right ear 10 minutes after the final treatment (day 27) with 2,4-dinitrofluorobenzene (DNFB) (Physiological saline was applied to a negative control group), and then pruritus was measured for 1 hour. FIG. 7 compares the pruritus-relieving effect of L-form N-acetylalanine, N-acetylthreonine, N-acetylarginine and N-acetyltryptophan with D/L-form and D-form N-acetylalanine and N-acetyltryptophan at 0.1% after the induction of pruritus with DNFB. The L-form N-acetylalanine, N-acetylthreonine, N-acetylarginine and N-acetyltryptophan significantly inhibited pruritus, whereas the D/L-form and D-form N-acetylalanine and N-acetyltryptophan had little effect. This result shows that the pruritus-inhibiting action by these substances is stereo-specific.

<Example 9> Synthesis of Acyl Derivatives of Tryptophan

[0119] In order to evaluate the effect of N-acyltryptophan compounds other than N-acetyltryptophan, N-propionyltryptophan, N-butryltryptophan, N-pentanoyltryptophan, N-undecanoyltryptophan, N-palmitoyltryptophan, N-(Z)-docos-13-enoyltryptophan and N-stearoyltryptophan, N-oleoyltryptophan were synthesized according to the reaction scheme described below. The reagents used in this example were purchased from Sigma-Aldrich (USA), TCI (Japan), Alfa Aesar (USA), Acros (USA), Hanawa (Japan), etc. and used without purification. The purity of the synthesized compounds and the progress of reaction were identified by thin layer chromatography (TLC) using the PLC Silica gel 60 F254, 0.5 mm (Merck). The substances separated by TLC were identified using UV lamps (254 nm, 365 nm). Separation was conducted by medium-pressure liquid chromatography (MPLC) using a silica gel column cartridge (4-120 g, RediSep Rf) and PLC2020 (Gilson) or by high-performance liquid chromatography (HPLC) using an Agilent 5 Prep-C18 100×21.2 mm column, a YL9100 Semi-prep HPLC system (YL9101S vacuum degasser, YL9111S binary pump, YL9120S UV/Vis detector; Young Lin Instrument). Mass analysis of the products was conducted with Agilent 6130 Quadrupole LC/MS. The NMR spectra for structural analysis of the products were measured with a Bruker ultra-shield 300 MHz NMR spectrometer and a Bruker ultra-shield 500 MHz NMR Spectrometer. Chloroform-d and dimethylsulfoxide-d.sub.6 (Cambridge Isotope Laboratories) were used as NMR solvents and tetramethylsilane (TMS) was used as an internal standard. The NMR data were presented in ppm units.

##STR00002##

<Example 9-1> Preparation of N-propionyltryptophan

[0120] First, for preparation of methylpropionyl L-tryptophanate, a mixture of propionic acid (2.36 mmol), L-tryptophan methyl ester hydrochloride (2.60 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) (2.60 mmol), hydroxybenzotriazole (HOBt) (2.60 mmol) and triethylamine (11.8 mmol) dissolved in dichloromethane was stirred at room temperature for 12 hours. The reaction mixture was concentrated, diluted with a saturated NaHCO.sub.3 solution, and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was combined, washed with brine, washed with 1 N HCl, and then washed again with brine. The organic solvent layer was dried on anhydrous MgSO.sub.4, concentrated and then purified by medium-pressure liquid chromatography (MPLC) using n-hexane and ethyl acetate. The yield was 74% and the characteristics of the methylpropionyl L-tryptophanate are as follows. .sup.1HNMR (500 MHz, chloroform-d) δ 8.19 (s, 1H), 7.61-7.53 (m, 1H), 7.39 (dt, J=8.2, 0.9 Hz, 1H), 7.22 (ddd, J=8.2, 7.0, 1.2 Hz, 1H), 7.16-7.07 (m, 1H), 7.00 (d, J=2.4 Hz, 1H), 6.04-5.88 (m, 1H), 5.00 (dt, J=7.9, 5.3 Hz, 1H), 3.73 (s, 3H), 3.44-3.29 (m, 2H), 2.21 (qd, J=7.6, 1.2 Hz, 2H), 1.14 (t, J=7.6 Hz, 3H). LC-MS (ESI), calcd for C.sub.15H.sub.18N.sub.2O.sub.3 274.1, found m/z 275.1 (M+H.sup.+).

[0121] In order to prepare N-propionyltryptophan from the methylpropionyl-L-tryptophanate, a NaOH (1.48 mmol) solution was added to the methylpropionyl-L-tryptophanate (0.37 mmol) dissolved in tetrahydrofuran and the mixture was stirred at room temperature for 12 hours. After adding water, the reaction mixture was extracted with dichloromethane. The aqueous layer was adjusted to pH 1 by adding 1 N HCl and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was dried on anhydrous MgSO.sub.4 and then concentrated. The yield was 92% and the characteristics of the N-propionyltryptophan are as follows. .sup.1H NMR (500 MHz, DMSO-d.sub.6) δ 10.82 (d, J=2.4 Hz, 1H), 8.03 (d, J=7.9 Hz, 1H), 7.53 (d, J=7.9 Hz, 1H), 7.35-7.27 (m, 1H), 7.13 (d, J=2.3 Hz, 1H), 7.06 (ddd, J=8.1, 6.9, 1.2 Hz, 1H), 6.98 (ddd, J=8.0, 6.9, 1.1 Hz, 1H), 4.46 (d, J=4.8 Hz, 1H), 3.15 (d, J=5.0 Hz, 1H), 3.01 (d, J=8.8 Hz, 1H), 2.08 (qd, J=7.5, 3.1 Hz, 2H), 0.94 (d, J=7.6 Hz, 3H). LC-MS (ESI), calcd for C.sub.14H.sub.16N.sub.2O.sub.3 260.1, found m/z 261.1 (M+H.sup.+).

Example 9-2> Preparation of N-butyryltryptophan

[0122] First, for preparation of methylbutyryl L-tryptophanate, butyric acid (2.36 mmol), a mixture of L-tryptophan methyl ester hydrochloride (2.60 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) (2.60 mmol), hydroxybenzotriazole (HOBt) (2.60 mmol) and triethylamine (11.8 mmol) dissolved in dichloromethane was stirred at room temperature for 12 hours. The reaction mixture was concentrated, diluted with a saturated NaHCO.sub.3 solution, and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was combined, washed with brine, washed with 1 N HCl, and then washed again with brine. The organic solvent layer was dried on anhydrous MgSO.sub.4, concentrated, and then purified by medium-pressure liquid chromatography (MPLC) using n-hexane and ethyl acetate. The yield was 83% and the characteristics of the methylbutyryl L-tryptophanate are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.15 (s, 1H), 7.61-7.51 (m, 1H), 7.39 (dt, J=8.1, 0.9 Hz, 1H), 7.22 (ddd, J=8.1, 7.0, 1.1 Hz, 1H), 7.15 (ddd, J=8.0, 7.0, 1.0 Hz, 1H), 7.01 (d, J=2.4 Hz, 1H), 5.98 (d, J=7.9 Hz, 1H), 5.01 (dt, J=7.9, 5.3 Hz, 1H), 3.73 (s, 3H), 3.39-3.29 (m, 2H), 2.16 (t, J=7.5 Hz, 2H), 1.70-1.58 (m, 3H), 0.93 (t, J=7.4 Hz, 3H). LC-MS (ESI), calcd for C.sub.16H.sub.20N.sub.2O.sub.3 288.2, found m/z 289.2 (M+H.sup.+).

[0123] In order to prepare N-butyryltryptophan from the methylbutyryl L-tryptophanate, a NaOH (1.48 mmol) solution was added to the methylbutyryl L-tryptophanate (0.37 mmol) dissolved in tetrahydrofuran and the mixture was stirred at room temperature for 12 hours. After adding water, the reaction mixture was extracted with dichloromethane. The aqueous layer was adjusted to pH 1 by adding 1 N HCl and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was dried on anhydrous MgSO.sub.4 and then concentrated. The yield was 94% and the characteristics of the N-butyryltryptophan are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.30 (s, 1H), 7.60 (d, J=8.1 Hz, 1H), 7.38 (dt, J=8.2, 0.9 Hz, 1H), 7.22 (ddd, J=8.1, 7.0, 1.2 Hz, 1H), 7.14 (ddd, J=8.0, 7.1, 1.0 Hz, 1H), 7.04 (d, J=2.3 Hz, 1H), 6.08 (d, J=7.6 Hz, 1H), 4.95 (dd, J=7.6, 5.4 Hz, 1H), 3.44-3.32 (m, 2H), 2.11-2.08 (m, 2H), 1.58 (q, J=7.4 Hz, 2H), 0.87 (t, J=7.4 Hz, 3H). LC-MS (ESI), calcd for C.sub.15H.sub.18N.sub.2O.sub.3 274.1, found m/z 275.1 (M+H.sup.+).

<Example 9-3> Preparation of N-pentanoyltryptophan

[0124] First, for preparation of methylpentanoyl L-tryptophanate, a mixture of pentanoic acid (2.36 mmol), L-tryptophan methyl ester hydrochloride (2.60 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) (2.60 mmol), hydroxybenzotriazole (HOBt) (2.60 mmol) and triethylamine (11.8 mmol) dissolved in dichloromethane was stirred at room temperature for 12 hours. The reaction mixture was concentrated, diluted with a saturated NaHCO.sub.3 solution, and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was combined, washed with brine, washed with 1 N HCl, and then washed again with brine. The organic solvent layer was dried on anhydrous MgSO.sub.4, concentrated, and then purified by medium-pressure liquid chromatography (MPLC) using n-hexane and ethyl acetate. The yield was 85% and the characteristics of the methylpentanoyl L-tryptophanate are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.14 (s, 1H), 7.56 (dt, J=8.0, 1.0 Hz, 1H), 7.39 (dd, J=8.1, 0.9 Hz, 1H), 7.22 (ddd, J=8.2, 7.0, 1.2 Hz, 1H), 7.15 (ddd, J=8.0, 7.1, 1.0 Hz, 1H), 7.01 (d, J=2.4 Hz, 1H), 5.97 (d, J=8.0 Hz, 1H), 5.00 (dt, J=7.9, 5.4 Hz, 1H), 3.46-3.23 (m, 2H), 2.32-2.09 (m, 2H), 1.61-1.54 (m, 2H), 1.51-1.19 (m, 2H), 0.90 (t, J=7.3 Hz, 3H). LC-MS (ESI), calcd for C.sub.17H.sub.22N.sub.2O.sub.3 302.2, found m/z 303.2 (M+H.sup.+).

[0125] In order to prepare N-pentanoyltryptophan from the methylpentanoyl L-tryptophanate, a NaOH (1.48 mmol) solution was added to the methylpentanoyl L-tryptophanate (0.37 mmol) dissolved in tetrahydrofuran and the mixture was stirred at room temperature for 12 hours. After adding water, the reaction mixture was extracted with dichloromethane. The aqueous layer was adjusted to pH 1 by adding 1 N HCl and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was dried on anhydrous MgSO.sub.4 and then concentrated. The yield was 90% and the characteristics of the N-pentanoyltryptophan are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.29 (s, 1H), 7.62-7.51 (m, 1H), 7.44-7.32 (m, 1H), 7.22 (ddd, J=8.2, 7.0, 1.1 Hz, 1H), 7.14 (ddd, J=8.0, 7.0, 1.0 Hz, 1H), 7.05 (d, J=2.4 Hz, 1H), 6.07 (d, J=7.7 Hz, 1H), 4.99 (dt, J=7.7, 5.4 Hz, 1H), 3.44-3.30 (m, 2H), 2.18-2.13 (m, 2H), 1.54 (p, J=7.6 Hz, 2H), 1.28 (dt, J=9.0, 7.2 Hz, 3H), 0.87 (t, J=7.3 Hz, 3H). LC-MS (ESI), calcd for C.sub.16H.sub.20N.sub.2O.sub.3 288.2, found m/z 289.2 (M+H.sup.+).

<Example 9-4> Preparation of N-undecanoyltryptophan

[0126] First, for preparation of methylundecanoyl L-tryptophanate, a mixture of undecanoic acid (2.36 mmol), L-tryptophan methyl ester hydrochloride (2.60 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) (2.60 mmol), hydroxybenzotriazole (HOBt) (2.60 mmol) and triethylamine (11.8 mmol) dissolved in dichloromethane was stirred at room temperature for 12 hours. The reaction mixture was concentrated, diluted with a saturated NaHCO.sub.3 solution and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was combined, washed with brine, washed with 1 N HCl, and then washed again with brine. The organic solvent layer was dried on anhydrous MgSO.sub.4, concentrated, and then purified by medium-pressure liquid chromatography (MPLC) using n-hexane and ethyl acetate. The yield was 91% and the characteristics of the methylundecanoyl L-tryptophanate are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.12 (s, 1H), 7.61-7.52 (m, 1H), 7.39 (dt, J=8.1, 0.9 Hz, 1H), 7.25-7.21 (m, 1H), 7.22-7.12 (m, 1H), 7.01 (d, J=2.4 Hz, 1H), 5.97 (d, J=7.9 Hz, 1H), 5.88-5.78 (m, 1H), 3.73 (s, 3H), 3.43-3.27 (m, 2H), 2.23-2.14 (m, 3H), 2.11-2.01 (m, 2H), 1.60 (s, 5H), 1.38 (q, J=7.0 Hz, 2H), 1.28 (d, J=2.1 Hz, 9H). LC-MS (ESI), calcd for C.sub.23H.sub.34N.sub.2O.sub.3 386.2, found m/z 387.2(M+H.sup.+).

[0127] In order to prepare N-undecanoyltryptophan from the methylundecanoyl L-tryptophanate, a NaOH (1.48 mmol) solution was added to the methylundecanoyl L-tryptophanate (0.37 mmol) dissolved in tetrahydrofuran and the mixture was stirred at room temperature for 12 hours. After adding water, the reaction mixture was extracted with dichloromethane. The aqueous layer was adjusted to pH 1 by adding 1 N HCl and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was dried on anhydrous MgSO.sub.4 and then concentrated. The yield was 88% and the characteristics of the N-undecanoyltryptophan are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.30-8.27 (m, 1H), 7.60 (d, J=7.9 Hz, 1H), 7.38 (d, J=8.1 Hz, 1H), 7.25-7.20 (m, 1H), 7.18-7.11 (m, 1H), 7.05 (d, J=2.3 Hz, 1H), 6.06 (d, J=7.5 Hz, 1H), 5.91-5.75 (m, 1H), 5.06-4.96 (m, 2H), 3.44-3.30 (m, 2H), 2.16-2.11 (m, 2H), 2.05 (q, J=7.2 Hz, 2H), 1.54 (d, J=7.3 Hz, 2H), 1.41-1.36 (m, 2H), 1.30-1.22 (m, 11H). LC-MS (ESI), calcd for C.sub.22H.sub.32N.sub.2O.sub.3 372.2, found m/z 373.2 (M+H.sup.+).

<Example 9-5> Preparation of N-palmitoyltryptophan

[0128] First, for preparation of methylpalmitoyl L-tryptophanate, a mixture of palmitoic acid (2.36 mmol), L-tryptophan methyl ester hydrochloride (2.60 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) (2.60 mmol), hydroxybenzotriazole (HOBt) (2.60 mmol) and triethylamine (11.8 mmol) dissolved in dichloromethane was stirred at room temperature for 12 hours. The reaction mixture was concentrated, diluted with a saturated NaHCO.sub.3 solution and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was combined, washed with brine, washed with 1 N HCl, and then washed again with brine. The organic solvent layer was dried on anhydrous MgSO.sub.4, concentrated and then purified by medium-pressure liquid chromatography (MPLC) using n-hexane and ethyl acetate. The yield was 84% and the characteristics of the methylpalmitoyl L-tryptophanate are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.11 (s, 1H), 7.56 (d, J=7.9 Hz, 1H), 7.51-7.33 (m, 1H), 7.19-7.06 (m, 1H), 7.01 (d, J=2.4 Hz, 1H), 5.99 (d, J=8.0 Hz, 1H), 5.00 (dt, J=8.0, 5.3 Hz, 1H), 3.73 (s, 3H), 3.39-3.29 (m, 2H), 2.38 (d, J=7.5 Hz, 2H), 2.19-2.15 (m, 2H), 1.67 (d, J=7.3 Hz, 2H), 0.91 (s, 3H). LC-MS (ESI), calcd for C.sub.28H.sub.44N.sub.2O.sub.3 456.2, found m/z 457.2 (M+H.sup.+).

[0129] In order to prepare N-palmitoyltryptophan from the methylpalmitoyl L-tryptophanate, a NaOH (1.48 mmol) solution was added to the methylpalmitoyl L-tryptophanate (0.37 mmol) dissolved in tetrahydrofuran and the mixture was stirred at room temperature for 12 hours. After adding water, the reaction mixture was extracted with dichloromethane. The aqueous layer was adjusted to pH 1 by adding 1 N HCl and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was dried on anhydrous MgSO.sub.4 and then concentrated. The yield was 89% and the characteristics of the N-palmitoyltryptophan are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.19 (s, 1H), 7.60 (d, J=7.9 Hz, 1H), 7.40 (d, J=8.1 Hz, 1H), 7.27-7.21 (m, 1H), 7.18-7.12 (m, 1H), 7.08 (d, J=2.3 Hz, 1H), 4.99 (dd, J=9.2, 3.8 Hz, 1H), 3.44-3.34 (m, 2H), 2.38 (d, J=7.5 Hz, 2H), 2.14 (d, J=11.8 Hz, 2H), 1.65 (d, J=7.4 Hz, 2H), 1.28 (m, 24 H), 0.91 (s, 3H). LC-MS (ESI), calcd for C.sub.27H.sub.42N.sub.2O.sub.3 442.2, found m/z 443.2 (M+H.sup.+).

<Example 9-6> Preparation of N-(Z)-docos-13-enoyl-L-tryptophan

[0130] First, for preparation of methyl-(Z)-docos-13-enoyl L-tryptophanate, a mixture of (Z)-docos-13-enoic acid (2.36 mmol), L-tryptophan methyl ester hydrochloride (2.60 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) (2.60 mmol), hydroxybenzotriazole (HOBt) (2.60 mmol) and triethylamine (11.8 mmol) dissolved in dichloromethane was stirred at room temperature for 12 hours. The reaction mixture was concentrated, diluted with a saturated NaHCO.sub.3 solution, and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was combined, washed with brine, washed with 1 N HCl, and then washed again with brine. The organic solvent layer was dried on anhydrous MgSO.sub.4, concentrated, and then purified by medium-pressure liquid chromatography (MPLC) using n-hexane and ethyl acetate. The yield was 74% and the characteristics of the methyl-(Z)-docos-13-enoyl L-tryptophanate are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.16 (s, 1H), 7.56 (dd, J=8.0, 1.1 Hz, 1H), 7.39 (dt, J=8.2, 0.9 Hz, 1H), 7.22 (ddd, J=8.2, 7.0, 1.1 Hz, 1H), 7.14 (ddd, J=7.9, 7.0, 1.0 Hz, 1H), 7.00 (d, J=2.4 Hz, 1H), 5.98 (d, J=7.9 Hz, 1H), 5.43-5.31 (m, 2H), 5.00 (dt, J=7.9, 5.3 Hz, 1H), 3.72 (s,3H), 3.39-3.29 (m, 2H), 2.20-2.13 (m, 2H), 2.04 (q, J=6.7 Hz, 4H), 1.61 (q, J=10.0, 7.5 Hz, 2H), 1.35-1.24 (m, 28H), 0.91 (t, J=6.9 Hz, 3H). LC-MS (ESI), calcd for C.sub.34H.sub.54N.sub.2O.sub.3 53/.4, found m/z 539.4 (M+H.sup.+).

[0131] In order to prepare N-(Z)-docos-13-enoyltryptophan from the methyl-(Z)-docos-13-enoyl L-tryptophanate, a NaOH (1.48 mmol) solution was added to the methyl-(Z)-docos-13-enoyl L-tryptophanate (0.37 mmol) dissolved in tetrahydrofuran and the mixture was stirred at room temperature for 12 hours. After adding water, the reaction mixture was extracted with dichloromethane. The aqueous layer was adjusted to pH 1 by adding 1 N HCl and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was dried on anhydrous MgSO.sub.4 and then concentrated. The yield was 92% and the characteristics of the N-(Z)-docos-13-enoyltryptophan are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.24 (s, 1H), 7.60 (dd, J=8.0, 1.0 Hz, 1H), 7.42-7.37 (m, 1H), 7.19-7.11 (m, 1H), 7.07 (d, J=2.4 Hz, 1H), 5.38 (td, J=4.4, 2.1 Hz, 2H), 4.95 (dt, J=7.5, 5.5 Hz, 1H), 3.44-3.33 (m, 2H), 2.14 (dd, J=8.6, 6.8 Hz, 2H), 2.09-1.97 (m, 4H), 1.55 (t, J=7.4 Hz, 2H), 1.28 (dd, J=19.4, 13.4 Hz, 30H), 0.90 (t, J=6.9 Hz, 3H). LC-MS (ESI), calcd for C.sub.33H.sub.52N.sub.2O.sub.3 524.4, found m/z 525.4 (M+H.sup.+).

<Example 9-7> Preparation of N-stearoyl-L-tryptophan

[0132] First, for preparation of methylstearoyl L-tryptophanate, a mixture of stearoic acid (2.36 mmol), L-tryptophan methyl ester hydrochloride (2.60 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) (2.60 mmol), hydroxybenzotriazole (HOBt) (2.60 mmol) and triethylamine (11.8 mmol) dissolved in dichloromethane was stirred at room temperature for 12 hours. The reaction mixture was concentrated, diluted with a saturated NaHCO.sub.3 solution, and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was combined, washed with brine, washed with 1 N HCl, and then washed again with brine. The organic solvent layer was dried on anhydrous MgSO.sub.4, concentrated, and then purified by medium-pressure liquid chromatography (MPLC) using n-hexane and ethyl acetate. The yield was 80% and the characteristics of the methylstearoyl L-tryptophanate are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.09 (d, J=15.2 Hz, 1H), 7.56 (dd, J=7.9, 1.0 Hz, 1H), 7.39 (dt, J=8.2, 0.9 Hz, 1H), 7.22 (ddd, J=8.1, 7.0, 1.2 Hz, 1H), 7.14 (ddd, J=7.9, 7.0, 1.0 Hz, 1H), 7.01 (d, J=2.4 Hz, 1H), 5.00 (dt, J=7.9, 5.3 Hz, 1H), 3.73 (s, 3H), 3.39-3.28 (m, 2H), 2.37 (t, J=7.5 Hz, 2H), 2.19-2.11 (m, 2H), 1.66 (t, J=7.4 Hz, 2H), 1.59 (t, J=7.4 Hz, 2H), 0.91 (s, 3H). LC-MS (ESI), calcd for C.sub.30H.sub.48N.sub.2O.sub.3 484.4, found m/z 485.4 (M+H.sup.+).

[0133] In order to prepare N-stearoyltryptophan from the methylstearoyl L-tryptophanate, a NaOH (1.48 mmol) solution was added to the methylstearoyl L-tryptophanate (0.37 mmol) dissolved in tetrahydrofuran and the mixture was stirred at room temperature for 12 hours. After adding water, the reaction mixture was extracted with dichloromethane. The aqueous layer was adjusted to pH 1 by adding 1 N HCl and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was dried on anhydrous MgSO.sub.4 and then concentrated. The yield was 84% and the characteristics of the N-stearoyltryptophan are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.27-8.17 (m, 1H), 7.60 (d, J=7.9 Hz, 1H), 7.39 (d, J=8.1 Hz, 1H), 7.23 (t, J=7.6 Hz, 1H), 7.15 (t, J=7.5 Hz, 1H), 7.07 (d, J=2.2 Hz, 1H), 6.01 (d, J=7.5 Hz, 1H), 4.98 (dt, J=7.5, 5.5 Hz, 1H), 3.46-3.34 (m, 2H), 2.37 (t, J=7.5 Hz, 2H), 2.17-2.12 (m, 2H), 1.68-1.63 (m, 2H), 1.56 (t, J=7.4 Hz, 2H), 1.29 (s, 24H), 0.91 (s, 3H). LC-MS (ESI), calcd for C.sub.29H.sub.46N.sub.2O.sub.2 470.4, found m/z 471.4 (M+H.sup.+).

<Example 9-8> Preparation of N-oleoyl-L-tryptophan

[0134] First, for preparation of methyloleoyl L-tryptophanate, a mixture of oleoic acid (2.36 mmol), L-tryptophan methyl ester hydrochloride (2.60 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI) (2.60 mmol), hydroxybenzotriazole (HOBt) (2.60 mmol) and triethylamine (11.8 mmol) dissolved in dichloromethane was stirred at room temperature for 12 hours. The reaction mixture was concentrated, diluted with a saturated NaHCO.sub.3 solution, and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was combined, washed with brine, washed with 1 N HCl, and then washed again with brine. The organic solvent layer was dried on anhydrous MgSO.sub.4, concentrated, and then purified by medium-pressure liquid chromatography (MPLC) using n-hexane and ethyl acetate. The yield was 73% and the characteristics of the methyloleoyl L-tryptophanate are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.18 (s, 1H), 7.56 (dd, J=7.9, 1.0 Hz, 1H), 7.39 (dt, J=8.1, 0.9 Hz, 1H), 7.29 (s, 1H), 7.22 (ddd, J=8.2, 7.1, 1.2 Hz, 1H), 7.14 (ddd, J=8.0, 7.0, 1.0 Hz, 1H), 7.00 (d, J=2.4 Hz, 1H), 5.99 (d, J=7.9 Hz, 1H), 5.37 (qd, J=4.1, 2.1 Hz, 2H), 5.00 (dt, J=8.0, 5.3 Hz, 1H), 3.72 (s, 3H), 3.39-3.28 (m, 2H), 2.20-2.13 (m, 2H), 2.08-1.99 (m, 5H), 1.60 (t, J=7.4 Hz, 2H), 1.34-1.28 (m, 24H), 0.92-0.89 (m, 3H). LC-MS (ESI), calcd for C.sub.30H.sub.46N.sub.2O.sub.3 482.4, found m/z 483.4 (M+H.sup.+).

[0135] In order to prepare N-oleoyltryptophan from the methyloleoyl L-tryptophanate, a NaOH (1.48 mmol) solution was added to the methyloleoyl L-tryptophanate (0.37 mmol) dissolved in tetrahydrofuran and the mixture was stirred at room temperature for 12 hours. After adding water, the reaction mixture was extracted with dichloromethane. The aqueous layer was adjusted to pH 1 by adding 1 N HCl and then extracted 3 times with ethyl acetate. The extracted organic solvent layer was dried on anhydrous MgSO.sub.4 and then concentrated. The yield was 86% and the characteristics of the N-oleoyltryptophan are as follows. .sup.1H NMR (500 MHz, chloroform-d) δ 8.22 (s, 1H), 7.61 (d, J=7.9 Hz, 1H), 7.40 (dt, J=8.1, 0.9 Hz, 1H), 7.23 (ddd, J=8.1, 6.9, 1.2 Hz, 1H), 7.15 (ddd, J=8.0, 7.1, 1.0 Hz, 1H), 7.08 (d, J=2.4 Hz, 1H), 5.37 (qd, J=5.3, 4.6, 2.3 Hz, 2H), 4.95 (dt, J=7.3, 5.6 Hz, 1H), 3.45-3.33 (m, 2H), 2.17-2.10 (m, 2H), 1.59-1.51 (m, 2H), 1.38-1.26 (m, 26H), 0.91 (d, J=6.8 Hz, 3H). C.sub.29H.sub.44N.sub.2O.sub.2 468.3, found m/z 469.3 (M+H.sup.+).

<Example 10> Preparation of N-acetyl-γ-glutammylalanine

[0136] N-Acetyl-γ-glutammylalanine was synthesized by Genescript (USA). The MS data of this compound are shown in FIG. 9.

<Example 11> Evaluation of Skin-soothing Effect and Severity of Atopic Dermatitis for Acyl Derivatives of Tryptophan and Acyl Derivatives of Alanine

[0137] Skin-soothing effect and the severity of dermatitis were evaluated for the acyl derivatives of tryptophan synthesized in Example 9, the acyl derivative of alanine synthesized in Example 10 and N-palmitoylalanine (purchased from Santacruz (USA)) according to the method of Example 4 (Table 2)

TABLE-US-00002 TABLE 2 Mouse 1 Licheni- Mouse 2 Erythema Edema Eschar Dryness Abrasion fication Sum Erythema Edema Eschar Dryness Abrasion Control 0 0 0 0 0 0 0 0 0 0 0 0 DNFB (D) 2 3 3 4 2 3 17 4 3 3 4 3 D + N-propionyl 2 2 2 2 2 2 12 2 2 2 3 2 L-tryptophan D + N-butyryl 1 2 2 2 1 2 10 2 1 1 2 2 L-tryptophan D + N-pentanoyl 2 2 2 2 1 2 11 2 2 1 2 1 L-tryptophan D + N-undecanoyl 1 2 1 1 2 2 9 2 1 2 1 2 L-tryptophan D + N-palmitoyl- 1 2 1 1 1 2 6 2 1 2 2 2 L-tryptophan D + N-(Z)-docos- 1 1 1 1 1 0 5 1 1 2 2 1 13-enoyl L-tryptophan D + N-stearyl- 2 2 2 2 2 2 12 2 2 1 2 2 L-tryptophan D + N-oleoyl- 2 1 2 2 2 3 12 1 1 1 2 2 L-tryptophan D + N-palmitoyl 1 2 1 1 1 1 7 2 1 1 1 1 L-alanine D + N-acetyly- 0 1 0 0 1 2 4 1 1 2 1 1 glutammyl- L-alanine Mouse 2 Mouse 3 Licheni Licheni- fication Sum Erythema Edema Eschar Dryness Abrasion fication Sum Mean Deviation Control 0 0 0 0 0 0 0 0 0 0 0 DNFB (D) 3 20 3 3 3 3 3 3 15 17.3 2.0 D + N-propionyl 2 13 2 1 2 1 2 1 9 11.3 1.7 L-tryptophan 3 D + N-butyryl 2 10 1 1 1 1 1 2 6 8.7 1.9 L-tryptophan D + N-pentanoyl 2 10 2 2 2 1 2 1 10 10.3 0.5 L-tryptophan D + N-undecanoyl 2 10 1 2 2 1 1 2 9 9.3 0.5 L-tryptophan D + N-palmitoyl- 1 10 2 2 1 2 1 2 10 8.7 1.9 L-tryptophan D + N-(Z)-docos- 0 7 2 1 2 2 1 1 9 7 1.6 13-enoyl L-tryptophan D + N-stearyl- 1 10 2 2 2 1 2 2 11 11 0.8 L-tryptophan D + N-oleoyl- 3 10 2 1 1 2 2 2 10 10.7 0.9 L-tryptophan D + N-palmitoyl 1 7 2 1 1 2 2 1 9 6.7 0.5 L-alanine D + N-acetyly- 2 8 1 1 1 0 1 2 6 6 2 glutammyl- L-alanine

[0138] As seen from Table 2 and FIG. 8, N-acyl-L-tryptophan and N-acyl-L-alanine showed significant skin-soothing and atopic dermatitis-treating effects.

[0139] While the exemplary embodiments have been shown and described, it will be understood by those skilled in the art that various changes in form and details may be made thereto without departing from the spirit and scope of this disclosure as defined by the appended claims.

(Project ID) 2017R1A2A1A17069822

(Ministry in Charge) Ministry of Science and ICT

(Research Management Agency) National Research Foundation of Korea

(Research Project Title) Support of Follow-up Study of Leading Research Project

[0140] (Research Title) Development of leukotriene derivative-based candidate materials for treatment of atopic dermatitis

(Contribution Rate) 1/2

(Research Institute) Jeonbuk National University

(Research Period) 2017 Sep. 1-2019 Feb. 28

(Project ID) 2017R1A5A2015061

(Ministry in Charge) Ministry of Science and ICT

(Research Management Agency) National Research Foundation of Korea

(Research Project Title) Leading Research Center Support Project

[0141] (Research Title) Research on metabolic inflammation

(Contribution Rate) 1/2

(Research Institute) Jeonbuk National University

(Research Period) 2017 Sep. 1-2019 Feb. 28