TYROSINASE-INHIBITING MOLECULES AND DERMOPHARMACEUTICAL COMPOSITION THAT INCLUDES THEM

Abstract

The present invention provides tyrosinase-inhibiting molecules of general formula (I) and a dermopharmaceutical or cosmetic composition that includes at least one of said tyrosinase-inhibiting molecules.

##STR00001##

Claims

1. Tyrosinase-inhibiting molecules of the following general formula (I): ##STR00012## wherein R.sup.1 and R.sup.2 are selected, independently therebetween, from H, HSO.sub.3 or one of their salts with a monovalent cation, M.sup.+SO.sub.3.sup.?, or with any physiologically acceptable cation, and represents a single or double bond, with the condition that R.sup.1 and R.sup.2 do not represent both H simultaneously.

2. Tyrosinase-inhibiting molecules, according to claim 1, selected from the following formulas (II) to (VI): II ##STR00013## R.sup.1 and R.sup.2 are both HSO.sub.3 and is a double bond III ##STR00014## one of R.sup.1 or R.sup.2 is HSO.sub.3, and the other of R.sup.1 and R.sup.2 is H and is a double bond ##STR00015## IV ##STR00016## R.sup.1 and R.sup.2 are both M.sup.+SO.sub.3.sup.? and is a single bond V ##STR00017## R.sup.1 is M.sup.+SO.sub.3.sup.? and R.sup.2 is H, is a double bond VI ##STR00018## R.sup.1 and R.sup.2 are both M.sup.+SO.sub.3.sup.? and is a double bond

3. Tyrosinase-inhibiting molecules, according to claim 1 or 2, wherein M is sodium, potassium or triethylammonium.

4. A dermopharmaceutical or cosmetic composition which comprises at least one tyrosinase-inhibiting molecule of general formula (I), according to claim 1, in combination with adequate excipients for the formulation thereof.

5. The dermopharmaceutical or cosmetic composition which comprises at least one tyrosinase-inhibiting molecule selected from formulas (II) to (VI), according to claim 2, in combination with adequate excipients for the formulation thereof.

6. The dermopharmaceutical or cosmetic composition, according to claim 4 or 5, wherein the tyrosinase-inhibiting molecule is present in the dermopharmaceutical or cosmetic composition in a concentration of 0.001-25% by weight.

Description

[0030] The invention is illustrated below through the following examples, which are illustrative, but not limiting, thereof and in reference to the attached figures, wherein:

[0031] FIG. 1: Shows a graphic view of the tyrosinase activity, as a percentage, of the molecules of formula (II) to (VI) at a concentration of 1 mM.

[0032] FIG. 2: Shows a graphic view of the reduction percentage of the melamine content in human melanocyte simples treated with the molecules of formulas (II) and (III).

Effectiveness Of The Molecules Of General Formula (I)

Tyrosinase Inhibition

[0033] In order to assess the possible tyrosinase inhibition of these molecules, a computational human tyrosinase model based on known tyrosinase structures of other organisms was initially developed, since human tyrosinase has not crystallized and, therefore, its actual three-dimensional structure is not available.

[0034] This computational model was used with the aim of virtually assessing the similarity of the different structures of formula (I). A theoretical solubility study using logP was carried out parallel to a synthetic viability study of each.

[0035] Table 1 below shows the results obtained.

TABLE-US-00001 TABLE 1 Average similarity LogP LogP Structure (Kcal/mol) (ionic species) (non-ionic species) [00009] ?8.0 0.74 3.11 [00010] ?8.1 (?1.89 (2.86)

[0036] Given the results, an in vitro assay was conducted on human melanocytes. In order to stimulate melanogenic activity in the cells they were treated with L-tyrosine. This compound, in addition to being a substrate of the tyrosinase enzyme, key to melanin synthesis, is capable of activating cell receptors that activate the melanogenesis-regulating signalling pathways (Slominski A, et al. L-tyrosine and L-dihydroxyphenylalanine as hormone-like regulators of melanocyte functions. Pigment Cell Melanoma Res. 2012; 25(1):14-27). This condition is aimed at stimulating melanogenesis in melanocytes for the purpose of extracting tyrosinase and testing the effect of the molecules of the invention.

[0037] Thus, human melanocytes were cultured in culture medium (#PCS-200-013, ATCC) and L-tyrosine (2 mM) for 3 days. After the stimulation treatment, the cells were trypsinised and lysated in PBS pH 7.0 with 1% Triton X-100. The cell lysate, which contains tyrosinase, was incubated together with the molecules of the invention at different concentrations (0.1 and 1 mM), L-DOPA and MBTH (Winder A J and Harris H. New assays for the tyrosine hydroxylase and dopa oxidase activities of tyrosinase. Eur. J. Biochem. 1991; 198(2):317-26). L-DOPA acts as a substrate for tyrosinase in the enzyme reaction and MBTH is a compound that bonds to the hydroquinone formed from the oxidation of L-DOPA, generating a colour complex. Each of the conditions used was prepared in triplicate. Lastly, absorbance at 492 nm was monitored using a spectrophotometer every 10 min for 2-5 h.

[0038] The results obtained are shown in table 2 and FIG. 1. The L-tyrosine-stimulated control is considered 100% to establish a reference value. In the case of the samples treated with the different molecules, molecule (III) has lower tyrosinase activity (82% at 0.1 mM and 44% at 1 mM), followed by the molecule of formula (II) (97% at 0.1 mM and 55% at 1 mM). In the presence of the molecules of formulas (IV) to (VI), tyrosinase activity is reduced (97%, 82%, 83% and 91%, respectively, at 1 mM), but to a lesser extent in comparison with the first two molecules.

TABLE-US-00002 TABLE 1 Percentage of tyrosinase activity of the molecules synthesised at two differerent concentrations (0.1 and 1 mM) Stimulated + Molecule of formula V Control Reference IV V M = V molecule II III M = K M = Na (C.sub.2H.sub.5).sub.3N M = K 0.1 mM 100 ? 2% 97 ? 3% 97 ? 0% 82 ? 2% >97% >97% >97% >97% 1 mM 84 ? 4% 55 ? 1% 44 ? 1% 97 ? 1% 82 ? 3% 83 ? 0% 91 ? 3% Reference molecule: [00011](E)-1,3-bis(p-hydroxyphenyl)-2-propen-1-one

Melanin Inhibition

[0039] With the aim of studying the inhibition of molecules in melanin, an in vitro assay was conducted on human melanocytes using similar conditions to those described in the tyrosinase inhibition assay. L-tyrosine is used to stimulate melanogenic activity in cells with the aim of extracting the melanin. Here, only the molecules with the best tyrosinase-inhibiting activity were tested (formulas (II) and (III)). In this experiment, the concentration of molecules used is the highest possible taking into account the melanocyte cytotoxicity value, 1.25 mM for the molecule of formula (II) and 0.33 mM for the molecule of formula (III).

[0040] Thus, human melanocytes are cultured in culture medium (#PCS-200-013, ATCC). L-tyrosine (2 mM) was added together with the molecule treatment. All the conditions were prepared in triplicate. After incubating the cells with the treatments for 3 days, they were trypsinised and lysated in 1M NaOH. Cell lysate absorbance at 340 nm was measured using a spectrophotometer. The absorbance value is directly proportional to melanin content.

[0041] As observed in FIG. 2, which shows the melanin content of the prepared samples, the L-tyrosine-stimulated control is considered 100% to establish a reference value. The difference between the melanin content of the samples treated with the molecules of formulas (II) (78?7%) and (III) (49?7%) and the sample treated only with L-tyrosine (100?3%) is significant, in accordance with Student's T-Test.

Solubility of the Synthesized Molecules

[0042] The following assay was conducted with the aim of studying and comparing the water solubility of the molecules.

[0043] Solutions are prepared in DMSO and in water for each of the molecules. All the samples are prepared at a final concentration of 50 mg/ml. After stirring for 1 hour at room temperature, the samples are filtered and a HPLC is performed.

[0044] In order to calculate the percentage of solubility of each of the molecules, the area of the peak of the sample dissolved in water and in DMSO obtained by HPLC is determined. The results are given as a percentage of solubility of the compound dissolved in water in the compound dissolved in DMSO.

[0045] Table 3 shows the results obtained. It can be observed that the reference molecule is fully water soluble at a concentration of 50 mg/ml. Molecules (II) and (III) are highly soluble at this concentration and the molecules of formulas (IV) to (VI) are fully water soluble at the tested concentration.

TABLE-US-00003 TABLE 2 Percentage of water solubility compared to the samples dissolved in DMSO Molecule of formula IV V V VI Concentration Ref. II III M = K M = Na M = (C.sub.2H.sub.5).sub.3N M = K 50 mg/ml 0% 81% 84% 100% 100% 100% 100%

Synthesis of the Molecules of the Invention

[0046] Formula (II): 5-[(E)-2-(4-hydroxy-3-sulfobenzoyl)-1-ethenyl]-2-hydroxybenzenesulfonic Acid

[0047] Under a nitrogen atmosphere, 1,039 g (4.33 mmol) of (E)-1,3-bis(p-hydroxyphenyl)-2-propen-1-one were slowly added to 5.04 g (43.3 mmol) of chlorosulfinic acid at 0? C. The reaction was maintained at room temperature for 22 h and the resulting mixture was slowly added to 25 ml of cold water. The aqueous phase obtained was extracted twice with 20 ml of ethyl acetate, the combined organic phases were washed with 10 ml of water and concentrated to dryness, to obtain 2,017 g of a solid containing 5-[(E)-2-(4-hydroxy-3-sulfobenzoyl)-1-ethenyl]-2-hydroxybenzenesulfonic acid (86.3% HPLC area).

[0048] 1H NMR (d-DMSO, 360 MHZ): ?6.86 (d, 1H), 6.91 (d, 1H), 7.62 (d, 1H), 7.70 (d, 1H), 7.82 (d, 1H), 7.86 (s, 1H), 8.14 (s, 1H), 8.21 (s, 1H).

Formula (III): 5-[(E)-3-(p-hydroxyphenyl)acryloyl]-2-hydroxybenzenesulfonic Acid

[0049] 5-acetyl-2-hydroxybenzenesulfonic Acid (Synthesis Intermediate)

[0050] 2 g (14.69 mmol) of 1-(p-hydroxyphenyl)-1-ethanone were slowly added to 17.6 g (146.9 mmol) of chlorosulfonic acid at 0? C. After 18 h at room temperature, 75 ml of cold water were added to the mixture and the mixture was extracted twice with 50 ml of ethyl acetate. The organic phase was vacuum concentrated to dryness to obtain 1.95 g of a raw product containing 1.71 g (54% yield) 5-acetyl-2-hydroxybenzenesulfonic acid and 0.24 g of 1-(p-hydroxyphenyl)-1-ethanone.

[0051] 1H NMR (d-DMSO, 360 MHz): ?2.50 (3H), 6.88 (d, 1H), 7.84 (d, 1H), 8.06 (s, 1H).

[0052] 5-[(E)-3-(p-hydroxyphenyl)acryloyl]-2-hydroxybenzenesulfonic Acid

[0053] 1.61 ml (26 mmol) of 98% sulphuric acid were slowly added to a mixture of 563 mg (2.60 mmol) of the previous raw product and 362 mg (2.60 mmol) of p-hydroxybenzaldehyde in 6.4 mL of ethanol at 0? C. The reaction was maintained at room temperature for 21 h and the mixture obtained was slowly added to a solution of 2 g sodium chloride in 10 ml of water at 0? C. The suspension was extracted twice with 20 ml of ethyl acetate and the combined organic phases were treated with anhydrous sodium sulphate and were concentrated to dryness. The product obtained was purified in a column with silica gel, eluting with a 100% dichloromethane to cichloromethane/methanol gradient of 8:2 to obtain 230 mg (27.6% yield) of 5-[(E)-3-(p-hydroxyphenyl)acryloyl]-2-hydroxybenzenesulfonic acid.

[0054] 1H NMR (d-DMSO, 360 MHZ): ?6.80-6.88 (2H), 6.91-6.97 (1H), 7.61-7.69 (2H), 7.69-7.78 (1H), 8.06-8.15 (1H), 8,18-8.25 (1H).

Formula (IV) (M=K): 5-[(E)-2-(4-hydroxy-3-sulfonatebenzoyl)-1-ethenyl]-2-hydroxybenzenesulfonate, Dipotassium Salt

[0055] Under a nitrogen atmosphere, 20.8 g (86.63 mmol) of (E)-1,3-bis(p-hydroxyphenyl)-2-propen-1-one were slowly added to 138.25 g (1.18 mol) of chlorosulfonic acid at 0? C. The reaction was maintained at room temperature for 19 h and the resulting mixture was slowly added to 650 ml of cold water. The aqueous phase obtained was extracted twice with 500 ml of ethyl acetate, the combined organic phases were washed with 250 ml of water and were concentrated to dryness to obtain 60.66 g of a product containing 66% of 5-[(E)-2-(4-hydroxy-3-sulfobenzoyl)-1-ethenyl]-2-hydroxybenzenesulfonic acid. 60.1 g of this product were suspended in 230 ml of water and an equimolar amount of potassium carbonate was slowly added to obtain a complete solution. 600 ml of 2-propanol were added to obtain a suspension. The solid was filtered, washed twice with 200 ml of 2-propanol and was vacuum dried at 100? C. to constant weight, to obtain 19 g (46% yield) of dipotassium salt of 5-[(E)-2-(4-hydroxy-3-sulfonatebenzoyl)-1-ethenyl]-2-hydroxybenzenesulfonate.

[0056] 1H NMR (d-DMSO, 360 MHZ): ?6.86 (d, 1H), 6.91 (d, 1H), 7.63 (d, 1H), 7.71 (d, 1H), 7.82 (d, 1H), 7.87 (s, 1H), 8.15 (s, 1H), 8.22 (s, 1H), 10.98 (brs, 1H), 11.18 (brs, 1H).

Formula (V) (M=Na): 5-[(E)-3-(p-hydroxyphenyl)acryloyl]-2-sodium Hydroxybenzenesulfonate

[0057] 1 g of 5-[(E)-3-(4-hydroxyphenyl)acryloyl]-2-hydroxybenzenesulfonic acid (3.12 mmol) was dissolved in 10 ml of 2-propanol and an equimolar amount of sodium bicarbonate was slowly added. The solid was filtered, washed twice with 2 ml of 2-propanol and vacuum dried to 50? C. to constant weight, obtaining 284 mg (27% yield) of 5-[(E)-3-(p-hydroxyphenyl)acryloyl]-2-sodium hydroxybenzenesulfonate.

[0058] 1H NMR (d-DMSO, 360 MHZ): ?6.80-6.88 (2H), 6.91-6.97 (1H), 7.61-7.69 (2H), 7.69-7.78 (1H), 8.06-8.15 (1H), 8.18-8.25 (1H), 10.98 (brs, 1H).

Formula (V) (M=(C.sub.2H.sub.5).sub.3N): 2-hydroxy-5-[2-(4-hydroxy-3-sulfonatebenzoyl)ethyl]-triethylammonium Benzenesulfonate

[0059] 10 g of 5-[(E)-3-(4-hydroxyphenyl)acryloyl]-2-hydroxybenzenesulfonic acid (31.23 mmol) were dissolved in 70 ml of 2-propanol and 13.05 ml of trimethylamine (93.69 mmol) were slowly added. The solid was filtered, washed twice with 20 ml of 2-propanol and vacuum dried at 50? C. to constant weight, obtaining 10.6 g (81% yield) of 5-[(E)-3-(p-hydroxyphenyl)acryloyl]-2-triethylammonium hydroxybenzenesulfonate.

[0060] 1H NMR (d-DMSO, 360 mHz): ?1.06 (t, 9H), 2.80 (q, 6H), 6.83 (d, 2H), 6.93 (d, 1H), 7.66 (s, 2H), 7.73 (d, 2H), 8.09 (dd, 1H), 8.21 (d, 1H).

Formula (VI) (M=K): 2-hydroxy-5-[2-(4-hydroxy-3-sulfonatebenzoyl)ethyl]-benzenesulfonate, Dipotassium Salt

[0061] In a high-pressure reactor, 1 g (2,10 mmol) of 5-[(E)-2-(4-hydroxy-3-sulfonatebenzoyl)-1-ethenyl]-2-hydroxybenzenesulfonate, dipotassium salt, was dissolved in 10 ml of water. 150 mg of Pd/C 10% were added and the mixture was hydrogenated at atmospheric pressure and 1,500 RPM for 72 h at room temperature. The reaction was controlled by 1H NMR. The reaction mixture was filtered through a layer of Celite? and concentrated to dryness, obtaining 2-hydroxy-5-[2-(4-hydroxy-3-sulfonatebenzoyl)ethyl]benzenesulfonate, dipotassium salt.

[0062] 1H NMR (d-DMSO, 360 MHZ): ?2.80 (t, 2H), 3.20 (t, 2H), 6.66 (d, 1H), 6.86 (d, 1H), 7.10 (d, 1H), 7.32 (s, 1H), 7.89 (d, 1H), 8.08 (s, 1H), 10.36 (brs, 1H), 11.12 (brs, 1H).

[0063] Reference molecule: (E)-1,3-bis(p-hydroxyphenyl)-2-propen-1-one

[0064] 16.06 g (165 mmol) of 98% sulphuric acid were slowly added to a mixture of 2 g (16.38 mmol) of p-hydroxybenzaldehyde and 2.23 g (16.38 mmol) of 1-(p-hydroxyphenyl)-1-ethanone in 20 ml of ethanol at room temperature. The reaction was maintained at room temperature for 23 h and the mixture obtained was slowly added to a solution of 10 g of sodium chloride in 33 ml of water at 0? C. The suspension was extracted three times with 16 ml of ethyl acetate and the combined organic phases were washed twice with 16 ml of water. After treating with anhydrous sodium sulphate, the organic phase was vacuum concentrated to dryness to obtain 3.58 g (91% yield, 97.4% HPLC area) of (E)-1.3-bis(p-hydroxyphenyl)-2-propen-1-one.

[0065] 1H NMR (d-DMSO, 360 mHz): ?6.33 (d, 1H), 6.71 (d, 2H), 7.45 (s, 2H), 7.51 (d, 2H), 7.76 (dd, 1H), 8.21 (d, 1H).

[0066] Sample Compositions of the Invention in Cream Form

TABLE-US-00004 Components % by weight Molecules of the invention 0.001-25 Glycerine 3 Butylene glycol 2 Disodium EDTA 0.1 Niacinamide 5 Ethylhexylglycerine 0.1 Phenoxyethanol 0.9 Citric acid 0.3 Sodium citrate 1.88 Xanthan gum 0.2 Polyacrylate Crosspolymer-6 0.8 Caprylic/capric triglyceride acid 5 Isonyl isononanoate 2 Isodecyl neopentanoate 5 Steareth-2 1 Glyceryl stearate, PEG 100 stearate 2 Phosphate cetyl 2 Dimethicone 2 Cetylic alcohol 2 Pentaerythrityl tetra-di-t-butyl 0.1 hydroxyhydrocinnamate Plankton extract 2 Aminoethylphosphinic acid 1 Acetyl glycyl beta-alanine 0.5 Salicylic acid 0.5 Lactic acid 1 Perfume 0.3 Water Up to 100%

[0067] Sample Compositions of the Invention in Serum Form

TABLE-US-00005 Components % by weight Molecules of the invention 0.001-25 Glycerine 8 Butylene glycol 10 Disodium EDTA 0.1 Niacinamide 5 Ethylhexylglycerine 0.1 Phenoxyethanol 0.9 Citric acid 0.3 Sodium citrate 1.88 Sodium metabisulfite 0.2 Polyacrylate Crosspolymer-6 1.5 1,3-propanedyol 6 TRIDECETH-9, PEG-40-hydrogenated 1.5 castor oil, Polysorbate 20 Potassium azeloyl diglycinate 5 Ascorbyl glucoside 3 Acetylglucosamine 1 Lepidium sativum extract 2 Water Up to 100%