α-MSH-antagonist dipeptide conjugates

Abstract
The invention relates to a dipeptide conjugate having general formula I, AA2-AA1-NH2, wherein A represent the radical corresponding to a monocarboxylic acid with general formula II, HOOC—R, in which: R represents a linear or branched aliphatic radical at C1-C24, which is optionally substituted by a hydroxyl group and which can comprise one or more unsaturations, preferably between 1 and 6 unsaturations, and/or which can comprise a phenyl group or lipoic acid or the reduced form thereof, dihydrolipoic acid or N-lipoyllysine; and AA1 and AA2 represent identical or different amino acids which are selected from the group containing Ala, Asn, Cys, Gln, Gly, Ile, Leu, Met, Phe, Pro, Ser, Thr, Trp, Tyr, Val, Asp, Glu, Arg, His, Lys, Orn, Dap, Dab, the corresponding homo-amino acids and the corresponding beta-amino acids in the form of enantiomers or diastereoisomers and mixtures thereof, including racemic mixtures.
Description

This application is a National Stage application of PCT/FR2005/001164, filed May 10, 2005, which claims priority from French patent applications FR 0405069, filed May 11, 2004, and 0411279, filed Oct. 22, 2004. The entire contents of each of the aforementioned applications are incorporated herein by reference.


This invention relates to new alpha-MSH antagonist dipeptide conjugates and their use as a medicine or as a depigmenting agent.


Melanocortine receptors belong to the superfamily of seven transmembrane receptors coupled to protein G and they stimulate the AMPc signal transduction channel (Cone et al. Recent Prog. Horm. Res. 1996, 51, pages 287-317). The melanocortine system is involved in many physiological channels including pigmentation, inflammation, the erectile function, food behavior, energy homeostasis, weight homeostasis and the exocrine glands function. The endogenic agonist ligands for these melanocortine receptors are derived by post-translational modification of the transcript of the proopiomelanocortine gene, that during differential treatment causes generation of α, β and γ hormones stimulating melanocytes (MSH) and corticotrophine (ACTH). Subtypes of melanocortine receptors are activated by all endogenic melanocortine peptides, except for the melanocortine MC2 receptor that is only stimulated by corticotrophine. The family of melanocortine receptors also has two endogenic antagonists, namely agouti and protein related to agouti (AGRP) (Lu et al. Nature 1994, 371, pages 799-802, Ollmann et al., Science 1997, pages 135-138, Shulter et al., Genes Dev. 1997, 11, pages 593-602) that are the only known antagonists discovered at the moment existing in the natural state of these receptors coupled with protein G. These are polypeptides of 132 and 49 amino acid residues respectively. The most studied melanocortine receptor ligands are MC, receptor ligands of melanocortine of the skin that are involved in pigmentation and coloring of animal hair coat (Hruby et al. Ann. N.Y. Acad. Sci. 1993, 680, pages 51-63; Lerner et al. Nature 1961, pages 189, 176; Mountjoy et al. Science 1992, 257, pages 1248-1251).


Nonapepdide 153 N-6 (Jayawickreme et al., J. Biol. Chem. 1994, 269, pages 29846-29854) (H-Met-Pro-D-Phe-Arg-d-Trp-Phe-Lys-Pro-Val-NH2: Ki=11 nM) is a synthetic antagonist of the receptor MC1. However, this compound has a high molecular weight and therefore a very limited therapeutic or cosmetic activity. Its size makes it difficult to optimize and its bioavailability is limited. It is also expensive and difficult to prepare.


Tripeptide D-Trp-Arg-Leu-NH2 (Proc. Natl. Acad. Sci. (1995), 92, pages 2894-2898) also has an antagonist activity. However, it contains tryptophan that is an unstable amino acid and therefore can cause stability problems during storage.


Patent EP 1 174 437 describes di- or tripeptides comprising a naphthyl group and in particular a naphthylalanyl group. However, the presence of the naphthyl group increases the fabrication price of the product. Furthermore in some countries such as Japan, unnatural amino acid based peptides cannot be sold for cosmetic applications. Furthermore, no dipeptide activity is indicated.


Surprisingly, the inventors discovered that dipeptides conjugated at the C-terminal with carboxylic acids have an antagonist activity of the MSH alpha. These antagonists have a very low molecular weight and are therefore easy to optimize, they have good bioavailability and are very easy to prepare.


Therefore, this invention relates to a dipeptide conjugate with general formula I below:

A-AA2-AA1-NH2  I

in which


A represents the radical corresponding to a monocarboxylic acid with the following general formula II:

HOOC—R  II

in which R represents


a linear or branched aliphatic radical in C1-C24, optionally substituted by a hydroxyl group, which can comprise one or more unsaturations, preferably between 1 and 6 unsaturations, and/or which can comprise a phenyl group,


or lipoic acid or the reduced form thereof, dihydrolipoic acid or N-lipoyllysine.


AA1 and AA2 represent identical or different amino acids chosen from the group consisting of Ala, Asn, Cys, Gln, Gly, Ile, Leu, Met, Phe, Pro, Ser, Thr, Trp, Tyr, Val, Asp, Glu, Arg, H is, Lys, Orn, Dap, Dab, the corresponding homo-amino acids and the corresponding beta-amino acids,


in the form of enantiomers or diastereoisomers and mixtures thereof including racemic mixtures.


Amino acids in the dipeptide conjugate with formula (I) may have a D, L or DL configuration if it is not specified otherwise.


Thus, dipeptide conjugates with formula (I) may comprise one or more asymmetric carbon atoms. Therefore, they may exist in the form of enantiomers or diastereoisomers. The invention includes these enantiomers, diastereoisomers and mixtures thereof, including racemic mixtures.


Within the framework of this invention, the following abbreviations have the following meanings:

    • Ala, Alanine,
    • Asn, Asparagine,
    • Cys, Cystein,
    • Gln, Glutamine,
    • Gly, Glycine,
    • Ile, Isoleucine,
    • Leu, Leucine,
    • Met, Methionine,
    • Phe, Phenylalanine or similar, particularly a halogenated derivative, and particularly para-fluoro-Phe, Homo-Phe, para-nitro-Phe or phenylglycine
    • Pro, Proline,
    • Ser, Serine,
    • Thr, Threonine,
    • Trp, Tryptophan,
    • Tyr, Tyrosine,
    • Val, Valine,
    • Asp, Aspartic acid,
    • Glu, Glutamic acid,
    • Arg, Arginine,
    • H is, Histidine,
    • Lys, Lysine,
    • Orn, Ornithine,
    • Dap, Diaminopropionic acid,
    • Dab, Diaminobutyric acid.


Note also that the dipeptide conjugates mentioned above according to this invention are obtained in the terminal form NH2 (in other words they present an amide function).


Dipeptide conjugates according to this invention are bonded to acid with formula II in the form of salts or esters. The conjugations according to this invention may be made by making the acid function of the amino acid react with the acid function of the formula II acid, or it is even possible to take advantage of the presence of a hydroxyl function on the formula II acid.


This invention relates to all these conjugations and non-functional conjugates. Conjugations may be physical or chemical.


Advantageously, at least one of the amino acids AA2 or AA1, and advantageously both of them, represent a basic amino acid, advantageously selected from the group consisting of Arg, H is, Dap, Dab, Orn or Lys, advantageously it will be Arg.


Advantageously, AA2 represents a basic amino acid advantageously selected from the group consisting of Arg, H is, Lys, Orn, Dap, Dab, advantageously it is Arg.


Advantageously, AA1 and/or AA2 do not represent Trp.


Advantageously, AA1 and/or AA2 do not represent Cys.


Advantageously, at least one of the amino acids AA1 or AA2 is selected from the group consisting of Ser and Pro.


Advantageously AA1 represents Pro.


Advantageously AA2 represents Ser.


Advantageously, the acid with formula (II) is a polyunsaturated fatty acid, in other words it comprises between 1 and 6 unsaturations. Even more advantageously, it is an omega-3 acid.


Among these omega-3 acids, there is particularly α-linolenic acid, cervonic acid, timnodonic acid and pinolenic acid. Cervonic, timnodonic and pinolenic acids are also known under the names 4,7,10,13,16,19-docosahexaenoic acid (DHA), 5,8,11,14,17-eicosapentaenoic acid (EPA) and 5,9,12-octodecatrienoic acid, respectively.


When A represents a monocarboxylic acid radical with general formula (II), it may advantageously be selected from among acetic acid, myristic acid, palmitic acid, hydroxydecenoic and decenoic acid, and particularly trans-10-hydroxy-Δ2-decenoic acid and trans-oxo-9-decene-2-oic acid.


Advantageously, acid with formula (II) is an acid selected from among lipoic acid (Lip) or its reduced form dihydrolipoic acid, N-lipoyllysine or phenylbutyric acid (Pbu).


Advantageously, A represents the radical corresponding to palmitic acid (Palm).


The dipeptide conjugates of the invention include the dipeptide conjugates selected from among the group consisting of:


a) A-Arg-His-NH2,


b) A-Arg-Arg-NH2,


c) A-Arg-Pro-NH2,


d) A-Arg-Lys-NH2,


e) A-Ser-Pro-NH2,


f) A-DPhe-Arg-NH2,


in which the definition of A is as given above.


In particular, the dipeptide conjugates in the invention may be selected from among the group consisting of


39) Palm-Arg-His-NH2,


41) Palm-Arg-Arg-NH2,


49) Palm-Arg-Pro-NH2,


50) Palm-Arg-Lys-NH2,


125) Palm-Ser-Pro-NH2,


269) Palm-DPhe-Arg-NH2,


362) Pbu-DPhe-Arg-NH2,


363) Lip-DPhe-Arg-NH2


Dipeptide conjugates according to this invention may be obtained either advantageously by classical chemical synthesis, or by enzymatic synthesis using any processes known to those skilled in the art.


This invention also relates to a cosmetic, dermatological or pharmaceutical composition or a food supplement comprising a dipeptide conjugate according to this invention and possibly a cosmetically or pharmaceutically acceptable excipient.


Dipeptide conjugates can be administered for their cosmetic or pharmaceutical use by topical route. They can also be used orally in food supplements, in other words in the nutraceutical domain.


Dipeptide conjugates according to the invention are preferably administered topically.


The cosmetic, pharmaceutical or dermatological composition according to this invention intended for topical administration may be presented in forms that are normally known for this type of administration, in other words particularly lotions, foams, gels, dispersions, sprays, serums, masks, body milk, pomades, solutions, emulsions, gels, or creams for example with excipients particularly for skin penetration in order to improve the properties and accessibility of the active ingredient. These compositions usually also contain the dipeptide conjugate according to this invention and usually also a physiologically acceptable medium, usually based on water or solvent, for example alcohols, ethers or glycols. They can also contain surface active agents, preservatives, stabilizers, emulsifiers, thickeners, other active constituents leading to a complementary or possibly synergic effect, trace elements, essential oils, perfumes, coloring agents, collagen, chemical or mineral filters, moisturizers or thermal water.


In the composition according to this invention, the dipeptide conjugate according to the invention may be present at a concentration of between 10−8 M and 10−3 M, advantageously between 10−7 M and 10−5 M.


This invention also relates to a dipeptide conjugate according to this invention or a pharmaceutical composition according to this invention for its use as a medicine, advantageously designed to prevent, improve or treat immunitary abnormalities, immunodeficiency, to regulate the body weight by controlling the appetite, to treat disorders of the central nervous system, to regulate satiety, to treat anorexia or some skin cancers.


This invention also relates to the use of a cosmetic composition according to this invention as a depigmenting agent to lighten or whiten the epidermis, to eliminate skin spots, particularly age spots or freckles, or to prevent pigmentation of the epidermis.


Finally, this invention relates to a cosmetic treatment process to lighten, depigment or whiten the epidermis, to eliminate skin spots and particularly age spots or freckles, or prevent pigmentation of the epidermis including application of a cosmetic composition according to this invention to the skin.


The following examples are given for non-limitative guidance.







EXAMPLE 1
Preparation of 361 Dipeptides According to the Invention

A bank of acylated dipeptides with 361 members was synthesized using SynPhase™ Lanterns and a “split and pool” strategy for color marking as described in the article by Feliu et al. (J. Comb. Chem., 2003, 5, pages 256-361).


Thus, these 361 compounds were synthesized on series D SynPhase™ Lanterns with Rink amide PS resin using the standard Fmoc (9-fluorenyl-methoxycarbonyl) synthesis strategy in the solid phase using a Multipin 96 arrangement format. Component blocks AA1 and AA2 were selected from a chemical assembly of 19 D and L amino acids including several types of lateral chains (alkyl, aromatic, acid, voluminous, basic) to produce 19×19=361 combinations.


The following chemical products were used:


Amino acids protected at the N-terminal end by an α-Fmoc, Fmoc-Ala-OH, Fmoc-D-Ala-OH, Fmoc-Arg(Pbf)-OH, Fmoc-D-Arg-(Pbf)-OH, Fmoc-His(Trt)-OH, Fmoc-D-His(Trt)-OH, Fmoc-Lys(Boc)-OH, Fmoc-Phe-OH, Fmoc-D-Phe-OH, Fmoc-Trp(Boc)-OH, Fmoc-D-Trp(Boc)-OH, Fmoc-Met-OH, Fmoc-Glu(OtBu)-OH, Fmoc-Ser(tBu)-OH, Fmoc-Leu-OH, Fmoc-Tyr(tBu)-OH, Fmoc-Gly-OH, Fmoc-Pro-OH, or Fmoc-Asn(trt)-OH group, were purchased from SENN chemicals and Advanced Chemtech.


The coupling agent, HBTU (hexafluorophosphate of 2-(1-H-benzotriazol-1-yl)-1,1,3,3-tetramethyl-uronium), was purchased from SENN chemicals.


N,N-dimethylformamide (DMF), dichloromethane, methanol, acetonitrile, ethyl ether, trifluoroacetic acid (TFA), piperidine were purchased from Riedel de Haen, Carlo Erba or Acros organics and used without purification.


N,N-diisopropylethylamine (DIEA), triisopropyl-silane, palmitic acid were purchased from Aldrich or Avocado. All reagents and chemical products were of analytic quality and they were used without any other purification.


D series Synphase Polystyrene Rink amide Lanterns were supplied by Mimotopes, Pty.


The standard procedure for manufacturing these dipeptides includes the following steps:


1—Fmoc Standard Deprotection Protocol


Fmoc deprotection steps were done by immersing lanterns immobilized on a support of 96 rods in a mix of dimethylsulfoxide (DMF)/piperidine (80/20, v/v) for 30 minutes. Rectangular polypropylene receptacles of the same size as a standard plate with 96 wells were used. The excess deprotection solution was simply eliminated by stirring the rod support vigorously.


2—Standard Washing Protocol


After the coupling or deprotection step, washing steps were carried out by dipping the lanterns arranged in a Multipin format into polypropylene receptacles containing DMF (3×5 min), methanol (2×5 min) and dichloromethane (DCM) (1×5 min), all in sequence. The lanterns were dried in air for 5 minutes under a vapor hood after the last washing with DCM.


3—Standard Coupling Protocol


0.4 M solutions of each Fmoc amino acid, HBTU and DIEA were prepared in DMF and were kept at 4° C. throughout the synthesis. 200 μl of amino acid solution were distributed in plates with 96 deep wells. 200 μl of DIEA solution and 200 μl of HBTU solution were then added and finally, the support of the rods supporting the lanterns was adapted to the deep wells plate for 2 hours.


4—Cleavage


500 μl of TFA/water/triisopropylsilane (95/2.5/2.5, v/v/v) solution was distributed in individual polypropylene tubes arranged in Micronic plates with 96 wells. Cleavage was done for 3 hours. The cleavage cocktail was concentrated directly from plates using a Jouan RC1010 vacuum centrifuge. Compounds were precipitated with dry diethyl ether, and were centrifuged and settled one by one. Precipitation, centrifuging and settlement operations were repeated twice. 500 μl of acetonitrile/water (50/50, v/v) containing 0.1% of TFA were distributed in each tube to solubilize the samples. The samples were then frozen at −80° C. and freeze dried. This operation was repeated twice to completely eliminate the triisopropylsilane purification group.


5—Preparation and Analysis of Samples


Complete banks and simple re-synthesized peptides were analyzed by CLHP in inverse phase and CL/SM. 500 μl of acetonitrile/water (50/50, v/v) containing 0.1% of TFA were distributed on the freeze-dried compounds. 10 μl of each tube was sampled for analysis of CLHP and CL/SM ESI+.


The CLHP analyses were carried out on a CLHP Waters Alliance 2690 system and a Waters 996 photodiode strip detector and a 50×4.6 mm Merck Chromolith Speed ROD C18 column. A flow rate of 5 ml/min and a gradient from 100% of B to 100% of C was used over 3 minutes (Eluant B, water/0.1% of TFA; Eluant C, acetronitrile/0.1% of TFA). Estimates of the purity are based on the percent of the area of peaks detected at 214 nm.


The CL/SM system was composed of a Waters Alliance 2690 CLHP coupled to a Micromass Platform II spectrometer (ionization by electronebulization mode; ESI+). All analyses were done using a 2.1×30 mm Waters Symmetry C18 column, 3.5 μm. A 600 μl/min flow rate and a gradient from 100% of B to 100% of C over 3 minutes were used (Eluant B, water/0.1% of TFA; Eluant C, acetonitrile/0.1% of TFA).


Mass spectra by positive ionic electronebulization were acquired at a solvent flow rate of 100 ml/min. Nitrogen was used both for the nebulizing gas and for the drying gas. Data were acquired in read mode m/z 400 to 1400 at intervals of 0.1−s; 10 readings were added to produce the final spectrum.


The molecular weights of all compounds were calculated using mono-isotopic masses (C=12.000, H=1.007, N=14.003, O=15.994, S=31.972).


Table 1 below contains the analysis results.









TABLE 1







Analytic results of the Palm-dipeptides bank










Dipeptide





conjugate


number


according


to the
Sequence
%
Molecular












invention
A
AA2
AA1
purity
weight
















 1
Palm
His
His
NH2
97
529.3 


 2
Palm
His
Phe
NH2
100 
539.4 


 3
Palm
His
Arg
NH2
100 
548.4 


 4
Palm
His
Trp
NH2
89
578.4 


 5
Palm
His
Glu
NH2
100 
521.3 


 6
Palm
His
Ala
NH2
100 
463.3 


 7
Palm
His
Ser
NH2
100 
479.3 


 8
Palm
His
Leu
NH2
100 
505.4 


 9
Palm
His
Tyr
NH2
100 
555.3 


 10
Palm
His
Gly
NH2
96
449.3 


 11
Palm
His
Pro
NH2
100 
489.3 


 12
Palm
His
Lys
NH2
100 
520.4 


 13
Palm
His
Asn
NH2
100 
506.3 


 14
Palm
His
Met
NH2
88
523.3 


 15
Palm
His
DPhe
NH2
81
539.4 


 16
Palm
His
DTrp
NH2
88
578.4 


 17
Palm
His
DArg
NH2
100 
548.4 


 18
Palm
His
DHis
NH2
97
529.3 


 19
Palm
His
DAla
NH2
88
463.3 


 20
Palm
Phe
His
NH2
100 
539.4 




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 22
Palm
Phe
Arg
NH2
100 
558.4 


 23
Palm
Phe
Trp
NH2
100 
588.4 


 24
Palm
Phe
Glu
NH2
100 
531.3 


 25
Palm
Phe
Ala
NH2
100 
473.3 


 26
Palm
Phe
Ser
NH2
100 
489.3 




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 28
Palm
Phe
Tyr
NH2
100 
565.4 


 29
Palm
Phe
Gly
NH2
100 
459.3 


 30
Palm
Phe
Pro
NH2
23
499.35


 31
Palm
Phe
Lys
NH2
100 
530.4 


 32
Palm
Phe
Asn
NH2
80
516.3 


 33
Palm
Phe
Met
NH2
100 
533.3 


 34
Palm
Phe
DPhe
NH2
100 
549.4 




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 36
Palm
Phe
DArg
NH2
100 
558.4 


 37
Palm
Phe
DHis
NH2
96
539.4 


 38
Palm
Phe
DAla
NH2
100 
473.3 


 39
Palm
Arg
His
NH2
94
548.4 


 40
Palm
Arg
Phe
NH2
100 
558.4 


 41
Palm
Arg
Arg
NH2
100 
567.4 


 42
Palm
Arg
Trp
NH2
95
597.4 


 43
Palm
Arg
Glu
NH2
100 
540.4 


 44
Palm
Arg
Ala
NH2
94
482.4 


 45
Palm
Arg
Ser
NH2
100 
498.4 


 46
Palm
Arg
Leu
NH2
100 
524.4 


 47
Palm
Arg
Tyr
NH2
93
574.4 


 48
Palm
Arg
Gly
NH2
100 
468.3 


 49
Palm
Arg
Pro
NH2
87
508.4 


 50
Palm
Arg
Lys
NH2
100 
539.4 


 51
Palm
Arg
Asn
NH2
91
525.4 


 52
Palm
Arg
Met
NH2
100 
542.4 


 53
Palm
Arg
DPhe
NH2
100 
558.4 


 54
Palm
Arg
DTrp
NH2
60
597.4 


 55
Palm
Arg
DArg
NH2
100 
567.4 


 56
Palm
Arg
DHis
NH2
100 
548.4 


 57
Palm
Arg
DAla
NH2
100 
482.4 


 58
Palm
Trp
His
NH2
93
578.4 


 59
Palm
Trp
Phe
NH2
100 
588.4 


 60
Palm
Trp
Arg
NH2
100 
597.4 




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 62
Palm
Trp
Glu
NH2
87
570.3 


 63
Palm
Trp
Ala
NH2
89
512.3 


 64
Palm
Trp
Ser
NH2
89
528.3 




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 66
Palm
Trp
Tyr
NH2
90
604.4 


 67
Palm
Trp
Gly
NH2
90
498.3 


 68
Palm
Trp
Pro
NH2
100 
538.4 


 69
Palm
Trp
Lys
NH2
99
569.4 


 70
Palm
Trp
Asn
NH2
95
555.3 


 71
Palm
Trp
Met
NH2
89
572.3 




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 73
Palm
Trp
DTrp
NH2
76
627.4 


 74
Palm
Trp
DArg
NH2
93
597.4 


 75
Palm
Trp
DHis
NH2
79
578.4 


 76
Palm
Trp
DAla
NH2
100 
512.3 


 77
Palm
Glu
His
NH2
94
521.3 


 78
Palm
Glu
Phe
NH2
100 
531.3 


 79
Palm
Glu
Arg
NH2
100 
540.4 


 80
Palm
Glu
Trp
NH2
82
570.3 


 81
Palm
Glu
Glu
NH2
100 
513.3 


 82
Palm
Glu
Ala
NH2
100 
455.3 


 83
Palm
Glu
Ser
NH2
100 
471.3 


 84
Palm
Glu
Leu
NH2
100 
497.4 


 85
Palm
Glu
Tyr
NH2
100 
547.3 


 86
Palm
Glu
Gly
NH2
100 
441.3 


 87
Palm
Glu
Pro
NH2
10
481.32


 88
Palm
Glu
Lys
NH2
100 
512.4 


 89
Palm
Glu
Asn
NH2
 7
498.31


 90
Palm
Glu
Met
NH2
100 
515.3 


 91
Palm
Glu
DPhe
NH2
100 
531.3 




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 93
Palm
Glu
DArg
NH2
100 
540.4 


 94
Palm
Glu
DHis
NH2
100 
521.3 


 95
Palm
Glu
DAla
NH2
100 
455.3 


 96
Palm
Ala
His
NH2
97
463.3 


 97
Palm
Ala
Phe
NH2
94
473.3 


 98
Palm
Ala
Arg
NH2
100 
482.4 


 99
Palm
Ala
Trp
NH2
98
512.3 


100
Palm
Ala
Glu
NH2
100 
455.3 


101
Palm
Ala
Ala
NH2
100 
397.3 


102
Palm
Ala
Ser
NH2
100 
413.3 


103
Palm
Ala
Leu
NH2
100 
439.3 


104
Palm
Ala
Tyr
NH2
100 
489.3 


105
Palm
Ala
Gly
NH2
100 
383.3 


106
Palm
Ala
Pro
NH2
100 
423.3 


107
Palm
Ala
Lys
NH2
100 
454.4 


108
Palm
Ala
Asn
NH2
100 
440.3 


109
Palm
Ala
Met
NH2
100 
457.3 


110
Palm
Ala
DPhe
NH2
100 
473.3 


111
Palm
Ala
DTrp
NH2
96
512.3 


112
Palm
Ala
DArg
NH2
100 
482.4 


113
Palm
Ala
DHis
NH2
84
463.3 


114
Palm
Ala
DAla
NH2
100 
397.3 


115
Palm
Ser
His
NH2
95
479.3 


116
Palm
Ser
Phe
NH2
100 
489.3 


117
Palm
Ser
Arg
NH2
100 
498.4 


118
Palm
Ser
Trp
NH2
96
528.3 


119
Palm
Ser
Glu
NH2
100 
471.3 


120
Palm
Ser
Ala
NH2
100 
413.3 


121
Palm
Ser
Ser
NH2
100 
429.3 


122
Palm
Ser
Leu
NH2
100 
455.3 


123
Palm
Ser
Tyr
NH2
97
505.3 


124
Palm
Ser
Gly
NH2
100 
399.3 


125
Palm
Ser
Pro
NH2
100 
439.3 


126
Palm
Ser
Lys
NH2
100 
470.4 


127
Palm
Ser
Asn
NH2
32
456.3 


128
Palm
Ser
Met
NH2
50
473.3 


129
Palm
Ser
DPhe
NH2
100 
489.3 


130
Palm
Ser
DTrp
NH2
93
528.3 


131
Palm
Ser
DArg
NH2
 0
498.4 


132
Palm
Ser
DHis
NH2
91
479.3 


133
Palm
Ser
DAla
NH2
100 
413.3 


134
Palm
Leu
His
NH2
92
505.4 


135
Palm
Leu
Phe
NH2
100 
515.4 


136
Palm
Leu
Arg
NH2
100 
524.4 


137
Palm
Leu
Trp
NH2
100 
554.4 


138
Palm
Leu
Glu
NH2
100 
497.4 


139
Palm
Leu
Ala
NH2
100 
439.3 


140
Palm
Leu
Ser
NH2
100 
455.3 


141
Palm
Leu
Leu
NH2
100 
481.4 


142
Palm
Leu
Tyr
NH2
100 
531.4 


143
Palm
Leu
Gly
NH2
100 
425.3 




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145
Palm
Leu
Lys
NH2
100 
496.4 


146
Palm
Leu
Asn
NH2
15
482.4 


147
Palm
Leu
Met
NH2
100 
499.3 


148
Palm
Leu
DPhe
NH2
100 
515.4 


149
Palm
Leu
DTrp
NH2
87
554.4 


150
Palm
Leu
DArg
NH2
100 
524.4 


151
Palm
Leu
DHis
NH2
86
505.4 


152
Palm
Leu
DAla
NH2
100 
439.3 


153
Palm
Tyr
His
NH2
96
555.3 




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155
Palm
Tyr
Arg
NH2
87
574.4 


156
Palm
Tyr
Trp
NH2
78
604.4 


157
Palm
Tyr
Glu
NH2
100 
547.3 


158
Palm
Tyr
Ala
NH2
100 
489.3 


159
Palm
Tyr
Ser
NH2
100 
505.3 


160
Palm
Tyr
Leu
NH2
100 
531.4 


161
Palm
Tyr
Tyr
NH2
98
581.4 


162
Palm
Tyr
Gly
NH2
100 
475.3 


163
Palm
Tyr
Pro
NH2
93
515.3 


164
Palm
Tyr
Lys
NH2
100 
546.4 


165
Palm
Tyr
Asn
NH2
100 
532.3 




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167
Palm
Tyr
DPhe
NH2
87
565.4 




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169
Palm
Tyr
DArg
NH2
90
574.4 


170
Palm
Tyr
DHis
NH2
92
555.3 


171
Palm
Tyr
DAla
NH2
100 
489.3 


172
Palm
Gly
His
NH2
81
449.3 


173
Palm
Gly
Phe
NH2
100 
459.3 


174
Palm
Gly
Arg
NH2
100 
468.3 


175
Palm
Gly
Trp
NH2
95
498.3 


176
Palm
Gly
Glu
NH2
100 
441.3 


177
Palm
Gly
Ala
NH2
100 
383.3 


178
Palm
Gly
Ser
NH2
100 
399.3 




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180
Palm
Gly
Tyr
NH2
100 
475.3 


181
Palm
Gly
Gly
NH2
100 
369.3 


182
Palm
Gly
Pro
NH2
100 
409.3 


183
Palm
Gly
Lys
NH2
81
440.3 


184
Palm
Gly
Asn
NH2
57
426.3 


185
Palm
Gly
Met
NH2
100 
443.3 


186
Palm
Gly
DPhe
NH2
100 
459.3 


187
Palm
Gly
DTrp
NH2
68
498.3 


188
Palm
Gly
DArg
NH2
100 
468.3 


189
Palm
Gly
DHis
NH2
90
449.3 


190
Palm
Gly
DAla
NH2
100 
383.3 


191
Palm
Pro
His
NH2
97
489.34


192
Palm
Pro
Phe
NH2
97
499.35




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197
Palm
Pro
Ser
NH2
99
439.31


198
Palm
Pro
Leu
NH2
72
465.36


199
Palm
Pro
Tyr
NH2
98
515.34


200
Palm
Pro
Gly
NH2
24
409.30


201
Palm
Pro
Pro
NH2
78
449.33


202
Palm
Pro
Lys
NH2
93
480.37


203
Palm
Pro
Asn
NH2
97
466.32


204
Palm
Pro
Met
NH2
97
483.32


205
Palm
Pro
DPhe
NH2
22
499.35


206
Palm
Pro
DTrp
NH2
96
538.36


207
Palm
Pro
DArg
NH2
37
508.38


208
Palm
Pro
DHis
NH2
73
489.34


209
Palm
Pro
DAla
NH2
59
423.32


210
Palm
Lys
His
NH2
92
520.38




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212
Palm
Lys
Arg
NH2
73
539.42


213
Palm
Lys
Trp
NH2
92
569.40


214
Palm
Lys
Glu
NH2
90
512.36


215
Palm
Lys
Ala
NH2
87
454.36


216
Palm
Lys
Ser
NH2
86
470.35


217
Palm
Lys
Leu
NH2
80
496.40


218
Palm
Lys
Tyr
NH2
97
546.38


219
Palm
Lys
Gly
NH2
89
440.34


220
Palm
Lys
Pro
NH2
21
480.37


221
Palm
Lys
Lys
NH2
96
511.41




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223
Palm
Lys
Met
NH2
89
514.36


224
Palm
Lys
DPhe
NH2
95
530.39


225
Palm
Lys
DTrp
NH2
92
569.40


226
Palm
Lys
DArg
NH2
94
539.42


227
Palm
Lys
DHis
NH2
94
520.38


228
Palm
Lys
DAla
NH2
83
454.36


229
Palm
Asn
His
NH2
28
506.33




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231
Palm
Asn
Arg
NH2
42
525.37


232
Palm
Asn
Trp
NH2
88
555.35




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234
Palm
Asn
Ala
NH2
80
440.31




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238
Palm
Asn
Gly
NH2
32
426.30


239
Palm
Asn
Pro
NH2
89
466.32


240
Palm
Asn
Lys
NH2
30
497.36


241
Palm
Asn
Asn
NH2
85
483.31


242
Palm
Asn
Met
NH2
77
500.31


243
Palm
Asn
DPhe
NH2
76
516.34


244
Palm
Asn
DTrp
NH2
57
555.35




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247
Palm
Asn
DAla
NH2
95
440.31


248
Palm
Met
His
NH2
85
523.33


249
Palm
Met
Phe
NH2
84
533.33


250
Palm
Met
Arg
NH2
76
542.37


251
Palm
Met
Trp
NH2
85
572.34


252
Palm
Met
Glu
NH2
87
515.31


253
Palm
Met
Ala
NH2
99
457.31


254
Palm
Met
Ser
NH2
55
473.30


255
Palm
Met
Leu
NH2
78
499.35


256
Palm
Met
Tyr
NH2
80
549.33


257
Palm
Met
Gly
NH2
63
443.29


258
Palm
Met
Pro
NH2
85
483.32


259
Palm
Met
Lys
NH2
88
514.36


260
Palm
Met
Asn
NH2
92
500.31


261
Palm
Met
Met
NH2
85
517.31


262
Palm
Met
DPhe
NH2
91
533.33


263
Palm
Met
DTrp
NH2
78
572.34


264
Palm
Met
DArg
NH2
57
542.37


265
Palm
Met
DHis
NH2
86
523.33


266
Palm
Met
DAla
NH2
31
457.31


267
Palm
DPhe
His
NH2
95
539.35


268
Palm
DPhe
Phe
NH2
76
549.36


269
Palm
DPhe
Arg
NH2
85
558.39


270
Palm
DPhe
Trp
NH2
70
588.37


271
Palm
DPhe
Glu
NH2
33
531.34


272
Palm
DPhe
Ala
NH2
97
473.33


273
Palm
DPhe
Ser
NH2
83
489.33


274
Palm
DPhe
Leu
NH2
79
515.38


275
Palm
DPhe
Tyr
NH2
93
565.36


276
Palm
DPhe
Gly
NH2
88
459.32


277
Palm
DPhe
Pro
NH2
50
499.35


278
Palm
DPhe
Lys
NH2
65
530.39


279
Palm
DPhe
Asn
NH2
77
516.34


280
Palm
DPhe
Met
NH2
97
533.33


281
Palm
DPhe
DPhe
NH2
76
549.36


282
Palm
DPhe
DTrp
NH2
87
588.37


283
Palm
DPhe
DArg
NH2
92
558.39


284
Palm
DPhe
DHis
NH2
96
539.35


285
Palm
DPhe
DAla
NH2
78
473.33


286
Palm
DTrp
His
NH2
69
578.36


287
Palm
DTrp
Phe
NH2
82
578.36


288
Palm
DTrp
Arg
NH2
79
588.37


289
Palm
DTrp
Trp
NH2
46
597.40


290
Palm
DTrp
Glu
NH2
71
627.38


291
Palm
DTrp
Ala
NH2
60
570.35




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293
Palm
DTrp
Leu
NH2
37
528.34


294
Palm
DTrp
Tyr
NH2
68
554.39


295
Palm
DTrp
Gly
NH2
69
604.37


296
Palm
DTrp
Pro
NH2
72
498.33


297
Palm
DTrp
Lys
NH2
96
538.36


298
Palm
DTrp
Asn
NH2
84
569.40


299
Palm
DTrp
Met
NH2
60
555.35


300
Palm
DTrp
DPhe
NH2
70
572.34


301
Palm
DTrp
DTrp
NH2
52
588.37


302
Palm
DTrp
DArg
NH2
86
627.38


303
Palm
DTrp
DHis
NH2
95
597.40




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306
Palm
DArg
Phe
NH2
42
548.38


307
Palm
DArg
Arg
NH2
60
558.39


308
Palm
DArg
Trp
NH2
42
567.42


309
Palm
DArg
Glu
NH2
73
597.40


310
Palm
DArg
Ala
NH2
82
540.37


311
Palm
DArg
Ser
NH2
74
482.36


312
Palm
DArg
Leu
NH2
34
498.36


313
Palm
DArg
Tyr
NH2
27
524.41


314
Palm
DArg
Gly
NH2
32
574.39


315
Palm
DArg
Pro
NH2
40
468.35




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317
Palm
DArg
Asn
NH2
40
539.42


318
Palm
DArg
Met
NH2
 9
525.37


319
Palm
DArg
DPhe
NH2
82
542.37


320
Palm
DArg
DTrp
NH2
30
558.39


321
Palm
DArg
DArg
NH2
20
597.40


322
Palm
DArg
DHis
NH2
70
567.42


323
Palm
DArg
DAla
NH2
83
548.38


324
Palm
DHis
His
NH2
75
482.36


325
Palm
DHis
Phe
NH2
66
529.35


326
Palm
DHis
Arg
NH2
53
539.35


327
Palm
DHis
Trp
NH2
69
548.38




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329
Palm
DHis
Ala
NH2
63
521.33


330
Palm
DHis
Ser
NH2
47
463.32


331
Palm
DHis
Leu
NH2
66
479.32


332
Palm
DHis
Tyr
NH2
79
505.37


333
Palm
DHis
Gly
NH2
89
555.35


334
Palm
DHis
Pro
NH2
96
449.31


335
Palm
DHis
Lys
NH2
90
489.34


336
Palm
DHis
Asn
NH2
87
520.38


337
Palm
DHis
Met
NH2
76
506.33


338
Palm
DHis
DPhe
NH2
96
523.33


339
Palm
DHis
DTrp
NH2
66
539.35




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341
Palm
DHis
DHis
NH2
84
548.38


342
Palm
DHis
DAla
NH2
52
529.35


343
Palm
DAla
His
NH2
70
463.32




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345
Palm
DAla
Arg
NH2
76
473.33


346
Palm
DAla
Trp
NH2
84
482.36




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348
Palm
DAla
Ala
NH2
53
455.31


349
Palm
DAla
Ser
NH2
11
397.30


350
Palm
DAla
Leu
NH2
78
413.30


351
Palm
DAla
Tyr
NH2
87
439.35




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353
Palm
DAla
Pro
NH2
17
383.29


354
Palm
DAla
Lys
NH2
86
423.32


355
Palm
DAla
Asn
NH2
94
454.36


356
Palm
DAla
Met
NH2
10
440.31


357
Palm
DAla
DPhe
NH2
86
457.31


358
Palm
DAla
DTrp
NH2
85
473.33


359
Palm
DAla
DArg
NH2
36
512.34


360
Palm
DAla
DHis
NH2
96
482.36




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Except for 35 members of the bank (shown in grey), all compounds were detected by a CL/SM ES+ analysis. The average purity determined based on the percent of the area of the expected peak detected at 214 nm on the chromatogram is greater than 83%.


EXAMPLE 2
Biological Properties of Five Dipeptide Conjugates According to this Invention

Experiments on inhibition of AMPc production were carried out on the M4Be human cell line with a concentration of 5×10−8 M of α-MSH. Five Palm-dipeptides according to this invention were introduced at different concentrations and each measurement was made in triplicate. Two or three series of experiments were made.


The tests were made as follows:


The M4Be human cell line (Jacubovich et al. Cancer Immunol. Immunother. 1979, 7, 59-64), a melanocytes cell line capable of producing melanines, was used in this study to determine the values of CI50.


The cells were maintained in the Dulbecco modified Eagle medium with 10% of foetal calf serum (FCS), 1 mM of glutamine, 100 U/ml of penicillin and 10−4 g/ml of streptomycine.


All cell lines were maintained at 37° C. in an atmosphere with 5% of CO2 and cell culture media were renewed every two days. The cells were applied in contact with a plate with 96 wells (Nunc, Roskilde) 24 hours before contact of dipeptides according to the invention.


AMPc was measured as follows:


Cells applied in contact the day before with 8×104 cells per well were put in the presence of one of the five dipeptide conjugates according to the invention at various concentrations for 10 minutes at 37° C. with 5×10−8 M of α-MSH. After this time, the lysis of the cells was made and the AMPc content was measured using a connection test box by competition (RPN225, Amersham Pharmacia Biotech). Each independent experiment was carried out at least twice in triplicate.


The peptidic activity was determined with reference to the AMPc content synthesized by untreated cells and the production of AMPc induced by α-MSH alone. The curves were adjusted and the values of CI50 were determined with non-linear regression in the GraphPad Prism (GraphPad software, San Diego, Calif., United States).


Table 2 below contains the results.









TABLE 2







Experiments on inhibition of AMPc production on M4Be


cells
















CI50
CI50
CI50
CI50




Purity
(μM)
(μM)
(μM)
(μM)


Compound
Sequence
(%)
exp1
exp2
exp3
aver.
















39
Palm-Arg-His-NH2
94
29
4.6
4.4
13


41
Palm-Arg-Arg-NH2
100
36
17

26


49
Palm-Arg-Pro-NH2
87
20
26

23


50
Palm-Arg-Lys-NH2
100
48
9.6

29


125
Palm-Ser-Pro-NH2
100
45
5.5
1.0
17









Thus, unexpectedly, the tested Palm-dipeptides appeared to be antagonists of the human MC1 receptor of melanocortine using M4Be melanoma cell lines. These dipeptide conjugates have a CI50 within a micromolar range. These dipeptides are the first example of short synthesis antagonist compounds binding to the MC1 receptor and they open up the field for small molecule non-peptidic antagonists of α-MSH.


In particular, these compounds comprise an arginine residue in position AA2. Interestingly, compound 125 (Palm-Ser-Pro-NH2) does not have any basic residue in its sequence, and has a value of CI50 equal to 17 μM. This result showed that the bond to the MC1 receptor does not necessarily require a positively charged radical.


With only two amino acid residues, these palmitoyled compounds can be considered as being leader compounds useful for design of non-peptide antagonists of α-MSH.

Claims
  • 1. Dipeptide conjugate with general formula I below: A-AA2-AA1-NH2  I
  • 2. Dipeptide conjugate according to claim 1, wherein AA2 represents a basic amino acid.
  • 3. Dipeptide conjugate according to claim 1 wherein it is selected from among the group consisting of: a) A-Arg-His-NH2,b) A-Arg-Pro-NH2, andc) A-Arg-Lys-NH2,in which the definition of A is as given in claim 1.
  • 4. Dipeptide conjugate according to claim 1, wherein it is selected from among the group consisting of 39) Palm-Arg-His-NH2,49) Palm-Arg-Pro-NH2, and50) Palm-Arg-Lys-NH2.
  • 5. Cosmetic or pharmaceutical composition comprising a dipeptide conjugate according to claim 1, and possibly a cosmetically or pharmaceutically acceptable excipient.
  • 6. Method for lightening or whitening the epidermis, for eliminating skin spots, or for preventing pigmentation of the epidermis comprising the administration of an effective amount of a cosmetic composition according to claim 5 or a cosmetic composition comprising the dipeptide Palm-Arg-Arg-NH2 to a patient in need thereof.
  • 7. Method according to claim 6, wherein the cosmetic composition is applied onto the skin.
  • 8. Dipeptide conjugate according to claim 2, wherein AA2 is Arg.
  • 9. Dipeptide conjugate according to claim 6, wherein the skin spots are age spots or freckles.
Priority Claims (2)
Number Date Country Kind
04 05069 May 2004 FR national
04 11279 Oct 2004 FR national
PCT Information
Filing Document Filing Date Country Kind 371c Date
PCT/FR2005/001164 5/10/2005 WO 00 5/23/2007
Publishing Document Publishing Date Country Kind
WO2005/115174 12/8/2005 WO A
US Referenced Citations (14)
Number Name Date Kind
5674839 Hruby et al. Oct 1997 A
5714576 Hruby et al. Feb 1998 A
5719126 Nordlund et al. Feb 1998 A
5786332 Girten et al. Jul 1998 A
5830994 D'Hinterland et al. Nov 1998 A
6054556 Hruby et al. Apr 2000 A
6228840 Wei et al. May 2001 B1
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Number Date Country
20070231284 A1 Oct 2007 US