Use of keratin hydrolysates to improve skin appearance and to prevent and / or reduce signs of skin aging.

Abstract

Non-therapeutic cosmetic oral use of a keratin hydrolysate as an agent for improving the quality and / or appearance of the skin, wherein the hydrolysate has a specific profile in total amino acids, contains at least 88% by weight of free amino acids relative to the total weight of amino acids in the hydrolysate, and the remainder of the amino acids in the hydrolysate is in the form of a peptide having a molecular weight of 800 daltons or less, and a corresponding cosmetic treatment method.

Description

Technical Field

[0001] The present invention relates to keratin hydrolysates, and more particularly, to the field of oral use of keratin hydrolysates as agents for improving skin quality, appearance and preventing and / or reducing signs of skin aging for cosmetic purposes.

Background Art

[0002] The skin consists of three layers: the epidermis, the dermis and the subcutaneous tissue. The epidermis, when in contact with the outside, is more significantly affected by attacks from the outside. The epidermis is covered by a hydrolipidic membrane and is composed of four layers: the stratum corneum, the stratum granulosum, the stratum spinosum and the stratum basale.

[0003] The skin, especially the epidermis, is the main defense barrier of the human body against external attacks such as air pollution, climate change and UV radiation. Therefore, the skin is constantly exposed to stress that ages the skin.

[0004] <s Generally, it is distinguished into intrinsic aging and extrinsic aging.

[0005] Intrinsic aging, also known as physiological aging ("chronological aging"), is the result of the slowdown of the regeneration of keratinocytes, which are cells in the surface layer of the skin, especially in the epidermis. The reduction of subcutaneous adipose tissue and the appearance of fine wrinkles are the main signs of intrinsic aging.

[0006] Extrinsic aging (photoaging) is characterized by loss of skin elasticity, impairment of skin barrier function and the appearance of deeper wrinkles. Extrinsic aging is essentially due to repeated exposure of the skin to the sun and is also associated with the appearance of darker spots that create uneven areas of appearance. This aging is also called photoaging or actinic aging.

[0007] There is still a need for new cosmetic products that improve skin quality and appearance, and especially prevent and / or reduce signs of skin aging.

[0008] In particular, there remains a need for new products that are effective and easy to administer.

[0009] This problem is solved by the present invention, which specifically addresses the use of certain keratin hydrolysates having particularly low molecular weights.

[0010] Such hydrolysates, as well as their use in improving the quality and / or appearance of nails and / or hair, are already known, particularly those described in the application WO2019 / 043128. However, this patent application does not suggest the use of such hydrolysates in improving the appearance of skin.

[0011] Furthermore, patent US7579317B2 describes obtaining keratin derivatives and, among numerous medical applications, improving skin health. These keratin derivatives are characterized by their high molecular weight, comparable to that of the raw material protein, and the fact that they are S-sulfonated. These are actually obtained by a digestion step consisting of sulfonation of the keratin substance by oxidative sulfilysis, followed by water extraction. These keratin derivatives are quite different from the hydrolysates used in the present invention.

[0012] Other aspects, advantages, and characteristics of the present invention are presented in the following description and examples. [Overview of the project] [Problems that the invention aims to solve]

[0013] The object of the present invention is a non-therapeutic cosmetic oral use of keratin hydrolysate as an agent for improving the quality and / or appearance of the skin, wherein the hydrolysate contains at least 88% by weight of free amino acids relative to the total weight of the amino acids in the hydrolysate, and the remainder of the amino acids in the hydrolysate is in the form of a peptide having a molecular weight of 800 daltons or less, and the hydrolysate has the following composition of each amino acid relative to the total amino acids: aspartic acid content in the range of 6.0-9.0% by weight, preferably 7.3-8.2% by weight; 4.0 Threonine content in the range of ~6.0% by weight, preferably 4.6~5.3% by weight; serine content in the range of 10.0~15.0% by weight, preferably 11.9~13.0% by weight; glutamic acid content in the range of 9.0~14.0% by weight, preferably 11.0~11.9% by weight; glycine content in the range of 7.0~10.0% by weight, preferably 8.4~9.1% by weight; alanine content in the range of 4.0~6.0% by weight, preferably 5.2~5.5% by weight; 6.0~10.0% by weight, preferably 7.8~8.5% by weight Valine content within the range; methionine content in the range of 0.0-0.5% by weight, preferably 0.1-0.4% by weight; isoleucine content in the range of 4.0-6.0% by weight, preferably 4.1-4.6% by weight; leucine content in the range of 6.0-9.0% by weight, preferably 6.7-7.7% by weight; tyrosine content in the range of 0.0-0.6% by weight, preferably 0.1-0.5% by weight; phenylalanine content in the range of 2.0-3.2% by weight, preferably 2.3-3.0% by weight; 1.0-3.0% by weight, preferably 1 The formulation has a lysine content in the range of 0.7 to 2.3% by weight, a histidine content in the range of 0.4 to 1.0% by weight, preferably 0.5 to 0.8% by weight, an arginine content in the range of 5.0 to 8.0% by weight, preferably 5.5 to 6.8% by weight, a proline content in the range of 9.0 to 14.0% by weight, preferably 9.5 to 11.8% by weight, a tryptophan content of less than 0.1% by weight, preferably equal to 0.0% by weight, and a cystine content in the range of 4.0 to 7.2% by weight, preferably 5.3 to 6.3% by weight.

[0014] This amino acid profile represents the weight percentage of each amino acid (free + bound) relative to the total number of amino acids (free + bound).

[0015] The object of the present invention is also a non-therapeutic cosmetic treatment method for improving skin quality and / or appearance, comprising at least one step of oral administration to an individual of a hydrolysate, wherein the hydrolysate contains at least 88% by weight of free amino acids relative to the total weight of the amino acids in the hydrolysate, and the remainder of the amino acids in the hydrolysate is in the form of a peptide having a molecular weight of 800 daltons or less, wherein the hydrolysate has the following composition in each amino acid relative to the total amino acids: an aspartic acid content in the range of 6.0 to 9.0% by weight, preferably 7.3 to 8.2% by weight;4 Threonine content in the range of 0.0-6.0% by weight, preferably 4.6-5.3% by weight; serine content in the range of 10.0-15.0% by weight, preferably 11.9-13.0% by weight; glutamic acid content in the range of 9.0-14.0% by weight, preferably 11.0-11.9% by weight; glycine content in the range of 7.0-10.0% by weight, preferably 8.4-9.1% by weight; alanine content in the range of 4.0-6.0% by weight, preferably 5.2-5.5% by weight; valine content in the range of 6.0-10.0% by weight, preferably 7.8-8.5% by weight. Content; Methionine content in the range of 0.0-0.5% by weight, preferably 0.1-0.4% by weight; Isoleucine content in the range of 4.0-6.0% by weight, preferably 4.1-4.6% by weight; Leucine content in the range of 6.0-9.0% by weight, preferably 6.7-7.7% by weight; Tyrosine content in the range of 0.0-0.6% by weight, preferably 0.1-0.5% by weight; Phenylalanine content in the range of 2.0-3.2% by weight, preferably 2.3-3.0% by weight; Lysine content in the range of 1.0-3.0% by weight, preferably 1.7-2.3% by weight. A non-therapeutic cosmetic treatment method for improving skin quality and / or appearance, having a histidine content in the range of 0.4 to 1.0 wt%, preferably 0.5 to 0.8 wt%; an arginine content in the range of 5.0 to 8.0 wt%, preferably 5.5 to 6.8 wt%; a proline content in the range of 9.0 to 14.0 wt%, preferably 9.5 to 11.8 wt%; a tryptophan content of less than 0.1 wt%, preferably equal to 0.0 wt%; and a cystine content in the range of 4.0 to 7.2 wt%, preferably 5.3 to 6.3 wt%. [Means for solving the problem]

[0016] The inventors have surprisingly shown that this hydrolysate can impart particularly advantageous properties to the skin, especially in terms of gloss, firmness, and elasticity.

[0017] In this document, "skin" refers to the epidermis.

[0018] Subjects administered with the hydrolysate according to the present invention have younger-looking, less tired-looking skin.

[0019] Hydrolyzed products were also observed to provide a good level of moisture to the skin.

[0020] In particular, the hydrolyzed products according to the present invention enable the prevention and reduction of the appearance of wrinkles and / or fine lines, and lead to skin thickening. In fact, a decrease in skin thickness is an indicator of skin aging.

[0021] Keratin derivatives known to have beneficial effects on the skin generally have high molecular weights, similar to those of keratin itself. Considering their keratin-like structure, their beneficial effects on the skin can be predicted.

[0022] However, no studies have shown that hydrolysates used in this invention, which have molecular weights and free amino acid content significantly different from those of natural keratin, have a significantly beneficial effect on skin appearance at low daily doses.

[0023] Other features and benefits of the present invention will become clear upon reading the detailed description below. [Brief explanation of the drawing]

[0024] [Figure 1] This graph shows the transformation (in units of 10⁻³m) as a function of time (in seconds). [Modes for carrying out the invention]

[0025] According to a first aspect, the present invention relates to the non-therapeutic oral use of a specific keratin hydrolyzate as an agent for improving the quality and / or appearance of the skin for cosmetic purposes.

[0026] According to a second aspect, the present invention relates to a method for a non-therapeutic cosmetic treatment for improving the quality and / or appearance of the skin, comprising oral administration of a specific keratin hydrolyzate to an individual.

[0027] The keratin hydrolyzate used according to the present invention has a high level of free amino acids and a specific amino acid profile.

[0028] In particular, tyrosine is present in the keratin hydrolyzate according to the present invention at a content of 0.6% by weight or less, preferably 0.5% by weight or less, and in a preferred embodiment 0.4% by weight or less, based on the total weight of the amino acids of the hydrolyzate. This low tyrosine content is the result of the implementation of a tyrosine extraction step in the method for preparing the hydrolyzate.

[0029] Advantageously, the hydrolyzate does not contain tyrosine, and any trace of this amino acid is due to the limits of the operating conditions of the equipment used during the extraction step.

[0030] Furthermore, cysteine is advantageously present in the keratin hydrolyzate according to the present invention at a content of 0.10% by weight or less, preferably 0.05% by weight or less, based on the total weight of the amino acids of the hydrolyzate, and in an even more preferred embodiment, the hydrolyzate does not contain cysteine.

[0031] On the other hand, the hydrolyzate according to the present invention contains cystine, which is a cysteine dimer, more particularly L-cystine, in a significant content. In fact, the cystine content is in the range of 4. ~ 7.2% by weight, preferably 5.3 ~ 6.3% by weight, based on the total weight of the amino acids of the hydrolyzate.

[0032] The hydrolysate according to the present invention contains at least 88% by weight, preferably at least 93% by weight, and in a more preferred embodiment at least 95% by weight of free amino acids relative to the total weight of the amino acids in the hydrolysate, with the remainder of the amino acids in the hydrolysate being in the form of peptides having a molecular weight of 800 daltons or less. The average molecular weight of the hydrolysate is in the range of 140 to 160 Da.

[0033] In fact, hydrolysates essentially contain amino acids, which are free amino acids (at least 88% by weight relative to the total weight of amino acids) and amino acids that are linked to form peptides, and hydrolysates further contain mineral substances and water.

[0034] Advantageously, the amino acid content of the hydrolysate, also called the total amino acids (free + bound), is in the range of 80% to 90% by weight relative to the total weight of the hydrolysate.

[0035] The keratin hydrolysate used in accordance with the present invention has the specific amino acid composition presented above, namely, the percentage of each amino acid (free + bound) relative to the total amino acids (free + bound).

[0036] Advantageously, the mineral content of the hydrolysate is 9% by weight or less, preferably less than 8% by weight, based on the total weight of the hydrolysate.

[0037] The mineral content is determined after calcining the hydrolyzed product at 550°C for 4 hours.

[0038] Amino acids are assayed according to the methods of EC Rule 152 / 2009.

[0039] According to this method, hydrolysis using an acid is performed beforehand to determine the total amount of amino acids.

[0040] To determine the amounts of free and total amino acids, the amino acids are separated by chromatography (HPLC) with an ion-exchange column and assayed by reaction with ninhydrin and photometric detection, typically at 570 nm.

[0041] While we do not wish to be bound by any theory, it appears that significant chemical hydrolysis, which produces these characteristics, particularly peptides with molecular weights of 800 Daltons or less, confers specific properties to the hydrolysates with respect to the skin.

[0042] Another advantage of the hydrolysate according to the present invention is that the hydrolysate is highly digestible and further approved as food grade. The hydrolysate according to the present invention has a pure amino acid digestibility of at least 90%. This value is very close to the highest possible value (100%). This property allows for good assimilation of the hydrolysate and, as a result, better efficacy of the free amino acids.

[0043] Digestibility is measured in vivo according to the method described in "Standardized amino acid digestibility of wheat distillers' dried grains with solubles in force-fed cockerels" by Cozannet P., Primot Y., Gady C., Metayer JP, Lessire M., Skiba F., and Noblet J., British Poultry Science, Feb. 2011;52(1):72-81.

[0044] Method for preparing hydrolyzed products The hydrolysates used in accordance with the present invention are obtained by carrying out preparation methods from natural, particularly poultry keratin material, and preferably from poultry feathers.

[0045] This natural keratinous substance mainly consists of high molecular weight polypeptides with a highly branched structure that makes them difficult for enzymes to access, and which make the aforementioned natural keratinous substance indigestible.

[0046] Advantageously, the hydrolyzed product is a hydrolyzed product of poultry keratin raw material.

[0047] Examples of domesticated poultry include hens, chickens, turkeys, and ducks.

[0048] Preferably, the hydrolysates used according to the present invention are not obtained from human keratin such as hair.

[0049] A method for preparing a keratin hydrolysate used in the present invention involves carrying out at least one chemical hydrolysis using an acid under conditions that allow for obtaining a hydrolysate in which at least 88% by weight of free amino acids relative to the total weight of amino acids in the hydrolysate are free amino acids, and the remainder of the amino acids in the hydrolysate is in the form of peptides having a molecular weight of 800 daltons or less.

[0050] The percentage of peptides in hydrolysates is generally in the range of 5 to 12% by weight relative to the total weight of amino acids in the hydrolysate.

[0051] In fact, since hydrolysis is partial, the percentage of peptides in the hydrolysate is not zero, but preferably at least 5% by weight of the total amino acids.

[0052] The chemical hydrolysis of the raw materials is carried out using an acid selected from hydrochloric acid, phosphoric acid, and sulfuric acid, preferably a strong acid, preferably hydrochloric acid.

[0053] Chemical hydrolysis is generally carried out at a temperature in the range of 110-115°C for a period of 1-8 hours, preferably 6-7 hours.

[0054] According to certain alternative methods, chemical hydrolysis The first chemical hydrolysis is carried out at a temperature of 60-80°C for a period of 4-5 hours, followed by A second chemical hydrolysis is performed at a temperature in the range of 100-115°C for a period of 5-7 hours. The process is carried out in two steps, and the two hydrolysis steps can be performed without an intermediate interruption step or by performing an intermediate interruption step between 1 hour and 7 days.

[0055] More precisely, the first chemical hydrolysis is carried out at 72°C for 4.5 hours, the second chemical hydrolysis is carried out at 107°C for 6 hours, and an intermediate interruption of 24-80 hours is performed between the two chemical hydrolysis processes.

[0056] The step of extracting tyrosine is carried out using a base, preferably selected from sodium hydroxide and potassium hydroxide, preferably sodium hydroxide.

[0057] The step of extracting tyrosine is a conventional step, and its implementation falls within the scope of the skills of those skilled in the art.

[0058] Unlike some keratin hydrolysates, the hydrolysate according to the present invention does not contain sulfocysteine.

[0059] The steps of chemical hydrolysis and tyrosine extraction may be followed by an optional step of purifying the resulting hydrolysate.

[0060] The steps of chemical hydrolysis and tyrosine extraction may be followed by an optional step of concentrating the resulting hydrolysate.

[0061] The steps of chemical hydrolysis and tyrosine extraction may be followed by an optional drying step, such as drying by spraying.

[0062] The purification, concentration, and drying steps are conventional steps, and their implementation is within the scope of the skills of those skilled in the art.

[0063] Advantageously, the resulting keratin hydrolysate is dried by spray drying to obtain the hydrolysate in a solid form.

[0064] use As already mentioned, the present invention relates to the cosmetic oral use of keratin hydrolysates according to the present invention as agents that improve the quality and / or appearance of the skin.

[0065] More specifically, the present invention relates to the cosmetic oral use of keratin hydrolysates that improve skin firmness and / or reduce loss of elasticity, thereby imparting a glossy and "healthy-looking" effect. Subjects administered the hydrolysates exhibited younger-looking, less tired-looking skin.

[0066] More specifically, the present invention relates to the cosmetic oral use of keratin hydrolysates for preventing and / or reducing the appearance of signs of skin aging, particularly wrinkles and / or fine lines.

[0067] In subjects treated with the hydrolysate, wrinkles appear less noticeable and shallower. The skin appears smoother and noticeably less imperfection.

[0068] In subjects administered the hydrolysate, the skin significantly thickened, which is one of the causes of wrinkle reduction. Furthermore, the skin exhibited better moisture retention.

[0069] According to a second aspect, the present invention relates to a non-therapeutic cosmetic treatment method for improving the quality and / or appearance of skin, comprising oral administration of a specific hydrolysate to an individual. Advantageously, the present invention relates to a cosmetic treatment method for preventing and / or reducing the appearance of signs of skin aging, particularly wrinkles and / or fine lines, and / or improving skin radiance and / or firmness and / or reducing loss of skin elasticity.

[0070] Advantageously, the use and method according to the present invention involves a daily administration of hydrolysate in an amount of 0.3 to 0.7 g, preferably 0.4 to 0.6 g, and in a preferred embodiment, 0.5 g of hydrolysate.

[0071] Preferably, the daily administration of hydrolysate is in the range of 0.3 to 0.7 g, preferably 0.4 to 0.6 g, and in a preferred embodiment, 0.5 g, for a period of at least 30 to 100 days, preferably at least 45 to 95 days, and in a preferred embodiment, for 90 days.

[0072] As can be seen from the examples, the administration of the hydrolysate is advantageously carried out in the form of two doses per day, preferably one dose in the morning and one in the evening.

[0073] According to a first preferred embodiment, in the use and methods of the present invention, the hydrolysate is administered in the form of a composition comprising the hydrolysate and at least one component selected from the group formed by zinc or a salt thereof, copper or a salt thereof, vitamins B, particularly B3, B5, B6 and / or B8, vitamin D3, vitamin C, vitamin A, vitamin E, silicon, selenium, magnesium, calcium, manganese, molybdenum, iron, yeast, plant extracts, particularly horsetail, β-carotene, collagen, hyaluronic acid, glutathione, and mixtures thereof.

[0074] According to a second preferred embodiment, in the use and method of the present invention, the hydrolysate is administered in the form of a composition comprising the hydrolysate and at least one of the following additional amino acids: additional cystine and / or additional arginine and / or additional proline and / or additional lysine and / or additional methionine, wherein the amount of additional cystine by weight is equal to the amount of cystine by weight of the hydrolysate, and / or the amount of additional arginine by weight is equal to the amount of arginine by weight of the hydrolysate, and / or the amount of additional proline by weight is equal to the amount of proline by weight of the hydrolysate, and / or the amount of additional lysine by weight is equal to the amount of lysine by weight of the hydrolysate, and / or the amount of additional methionine by weight is 10 mg / day to 80 mg / day.

[0075] The following examples illustrate the present invention without limiting its scope. [Examples]

[0076] [Example 1] Compliant hydrolysates The three hydrolysates according to the present invention were prepared from three different batches of feathers according to the same method. Each time, the feathers were freshly collected from the applicant's partners, and as a result, the properties of the feathers (chicken, turkey, duck, goose, etc.) may vary.

[0077] A. Preparation of hydrolyzed products Each time, 4,500 kg of poultry feathers are introduced into a 50,000-liter reactor / hydrolysis unit.

[0078] The first step of chemical hydrolysis is carried out by adding 18,000 liters of hydrochloric acid (24%), and the hydrolysis is carried out at 72°C for 4.5 hours.

[0079] Store the obtained product at room temperature for 48 hours (intermediate interruption).

[0080] Next, a second chemical hydrolysis is carried out by heating at 105°C for 6 hours without adding acid.

[0081] The obtained product is cooled.

[0082] Next, the step of extracting tyrosine is carried out by raising the pH to approximately 7 using sodium hydroxide.

[0083] The resulting solution is desalted by electrodialysis and then dried by spraying.

[0084] 4200 kg of hydrolyzed product is obtained in a dry form.

[0085] B. Determination of the composition of the hydrolysate Amino acids are assayed according to the methods of EC Rule 152 / 2009.

[0086] The amino acids are separated by chromatography (HPLC) with an ion-exchange column and assayed by reaction with ninhydrin and photometric detection at 570 nm.

[0087] The values ​​presented are expressed in grams of amino acids relative to the total number of amino acids.

[0088] Table 1 shows the aminograms of all amino acids in hydrolyzate I, i.e., the content of each amino acid relative to the total amino acids.

[0089] [Table 1]

[0090] Hydrolyzate I contains 6.6% by weight of mineral material and 83.3% by weight of free amino acids.

[0091] Table 2 shows the aminograms of all amino acids in hydrolysate II, i.e., the content of each amino acid relative to the total amino acids.

[0092] [Table 2]

[0093] Hydrolyzate II contains 7.6% by weight of mineral material and 80.4% by weight of free amino acids.

[0094] Table 3 shows the aminograms of all amino acids in hydrolyzate III, i.e., the content of each amino acid relative to the total amino acids.

[0095] [Table 3]

[0096] Hydrolyzate III contains 7.1% by weight of mineral material and 83.0% by weight of free amino acids.

[0097] C. Digestibility Table 4 below shows the net digestibility coefficients for each amino acid of hydrolysate I, expressed as percentages, and the average net digestibility of all amino acids.

[0098] These values ​​were obtained using the following protocol for young roosters with cecal resection, a reference model for measuring the bioavailability of amino acids in the animal kingdom.

[0099] Experimental protocol Digestiveness measurements were performed on young adult roosters that had undergone cecal removal and were housed in individual cages. Outside of the study period, they were fed a standard diet.

[0100] We used two repeated samples from four young roosters that had undergone cecal removal.

[0101] All animals were fasted for 24 hours before being administered a single 80g meal consisting of 24g of hydrolyzed sample I mixed with 56g of sugar.

[0102] Over the following 48 hours, all fecal matter, including endogenous loss, is collected in two 24-hour periods to avoid fermentation and potential deterioration.

[0103] These feces are carefully sampled, ensuring they are free of any impurities such as feathers, and then frozen (-80°C).

[0104] Next, the feces are dried in an oven, grouped, and mixed into two pools, corresponding to two repetitions of the four animals used for the hydrolysis product.

[0105] We will analyze the two pools.

[0106] Nutritional analysis (dry substance, crude protein (Dumas method), and amino acids) is performed on hydrolysates, young rooster feces, and endogenous losses.

[0107] These data are used to calculate net protein and amino acid digestibility.

[0108] Regarding protein digestibility, since urea nitrogen is present in bird droppings, protein nitrogen is measured in feces (Terpstra method).

[0109] Therefore, the net nutrient digestibility, measured as a percentage, is calculated using a quantitative method based on the difference between the amount of hydrolyzed product ingested and the amount of feces excreted, corrected for endogenous losses, according to the following formula.

[0110]

number

[0111] The digestibility values ​​for hydrolyzate I are shown in Table 4 below.

[0112] [Table 4]

[0113] The net digestibility of amino acids in hydrolysate I according to the present invention is very high, being very close to the highest possible value (100%). As a result, the hydrolysate according to the present invention is readily assimilated by the body.

[0114] The same results are obtained for the net digestibility of amino acids in hydrolysates II and III.

[0115] [Example 2] Measurement of beauty activity The following examples were carried out using a commercially available keratin-based product as Product A, which contains hydrolysate II according to the present invention, and as comparative Product C.

[0116] Each capsule of Product A contained 125 mg of keratin hydrolysate II prepared on top of 205 mg of corn maltodextrin and 10 mg of magnesium stearate as excipients.

[0117] According to available information, product C contains a wool keratin derivative with a molecular weight greater than 950 Da. The protein fraction of the keratin derivative is between 60% and 70% by weight of the total weight of the derivative, and the mineral fraction is between 30% and 40% by weight. The proportion of free amino acids is less than 6% by weight of the amino acids in the keratin derivative. The protein fraction consists of 80% by weight of peptides composed of 3 to 35 amino acids. The net digestibility of product C, determined according to the method described in Example 1.C above, is less than 75%.

[0118] Each capsule of Product C contains 125 mg of a keratin derivative and 205 mg of corn maltodextrin and 10 mg of magnesium stearate as excipients.

[0119] The placebo consists only of 330 mg of corn maltodextrin (excipient) and 10 mg of magnesium stearate (excipient).

[0120] A double-blind, randomized, placebo-controlled trial was conducted on 99 healthy subjects aged 35–65 years (33 subjects received product A, 33 received control product C, and 33 received a placebo). Other inclusion criteria were listed below: visible crow's feet, mild to moderate skin laxity, and a phototype ranging from I to IV on the Fitzpatrick scale.

[0121] Products A, C, and placebo were administered orally at a rate of 4 capsules per day (2 capsules in the morning and 2 capsules in the evening) for 90 days, and interim results were measured after 45 days.

[0122] Group 1 received a daily dose of 0.5g of hydrolyzed product II (4 capsules of product A), Group 2 received a daily dose of 0.5g of keratin derivative (4 capsules of product C), and Group 3 received 4 capsules of placebo per day.

[0123] A. Shine Skin luster was measured using a CM700D spectrophotometer / colorimeter (Konica Minolta, Inc.).

[0124] The measurement parameter was the gloss value at 8°.

[0125] The instrument emits diffused light that reaches the skin through an aperture located at the end of the illumination bulb.

[0126] Next, a sensor positioned at an angle of 8° to the vertical axis of the aperture detects reflected light and calculates a parameter called the "gloss value."

[0127] The gloss value is used to manage the sheen of a color.

[0128] The difference between the skin gloss measurement results at 45 days (D45) and the gloss measurement results at the start of the test (D0), and the difference between the skin gloss measurement results at 90 days (D90) and the gloss measurement results at the start of the test (D0), are reported in Table 5 below.

[0129] [Table 5]

[0130] The hydrolyzed product (product A) according to the present invention makes it possible to obtain smoother skin than comparative product C after 45 days, and the smoothness becomes even more pronounced after 90 days.

[0131] An additional trial was conducted by administering 1 g of hydrolyzed II daily for 45 days, but this trial did not yield better results than the trial of administering 0.5 g of hydrolyzed II for 45 days.

[0132] B. Tightening and elasticity Skin firmness and elasticity are measured using a suction / stretching method (Cutometer® MPA580, Courage+Khazaka, electronic GmbH).

[0133] A vacuum (450 mbar) is generated inside the device, the skin is drawn into the probe opening for 2 seconds, and then released after a specified time (2 seconds).

[0134] The principle of this method is illustrated in Figure 1, and can be transformed as a function of time (in seconds) (10 -3 (In meters)

[0135] The parameter R0 corresponds to the skin's elasticity, which is the first maximum amplitude (Uf) of the curve and represents the passive behavior of the skin against force. The parameter R0 is inversely proportional to the degree of skin tightness. The resulting values ​​can be expressed as absolute values, such as an increase in skin tightness.

[0136] The parameter R2 corresponds to total elasticity or full elasticity, which is the ratio (Ua / Uf) between the residual deformation of the skin and its maximum elongation, indicating the skin's ability to return to its initial recovery state after a stressful event.

[0137] Tightness is measured as the absolute value of the parameter R0.

[0138] The difference between the skin tightening measurement results at 45 days (D45) and the tightening measurement results at the start of the study (D0), and the difference between the skin tightening measurement results at 90 days (D90) and the tightening measurement results at the start of the study (D0), are recorded in Table 6 below.

[0139] [Table 6]

[0140] The hydrolysate according to the present invention (product A) allows for firmer skin after 45 days of treatment compared to comparative product C.

[0141] An additional trial was conducted by administering 1 g of hydrolyzed II daily for 90 days, but this trial did not yield better results than the trial of administering 0.5 g of hydrolyzed II for 90 days.

[0142] Elasticity is measured using the parameter R2.

[0143] The difference between the skin elasticity measurement results at 45 days (D45) and the elasticity measurement results at the start of the test (D0), and the difference between the elasticity measurement results at 90 days (D90) and the elasticity measurement results at the start of the test (D0), are recorded in Table 7 below.

[0144] [Table 7]

[0145] The hydrolyzed product (product A) according to the present invention makes it possible to obtain skin that is more elastic than comparative product C after 45 days.

[0146] An additional trial was conducted by administering 1 g of hydrolyzed II daily for 45 days, but this trial did not yield better results than the trial of administering 0.5 g of hydrolyzed II for 45 days.

[0147] C. Effects on wrinkles / fine lines The surface of the skin is quantitatively evaluated using Primos3D (GFMesstechnik GmbH).

[0148] Primos3D is a non-contact in vivo skin measurement device based on structured light projection.

[0149] Combined with comprehensive 3D measurement and evaluation software, the sensor enables the evaluation of skin surface characteristics such as wrinkle / fine line depth, length, and area (surface area).

[0150] In this study, the depth, length, and surface area of ​​wrinkles were measured in the "crow's feet" area.

[0151] This trial was conducted in comparison to a placebo.

[0152] The differences between the measurement results of wrinkle / fine wrinkle depth / length / surface area at 45 days (D45) and the measurement results at the start of the test (D0), and the differences between the measurement results of wrinkle / fine wrinkle depth / length / surface area at 90 days (D90) and the measurement results at the start of the test (D0), are reported in Table 8 below.

[0153] [Table 8]

[0154] The hydrolyzed product according to the present invention makes it possible to reduce wrinkles / fine lines from day 45.

[0155] In addition, the study collected user feedback and stated that 80% of subjects who used the hydrolyzed product according to the present invention reported that their skin was smoother, more supple, and better moisturized.

Claims

1. Non-therapeutic cosmetic oral use of keratin hydrolysates as agents for improving skin quality and / or appearance, wherein the hydrolysates contain at least 88% by weight of free amino acids relative to the total weight of the amino acids in the hydrolysates, the remainder of the amino acids in the hydrolysates being in the form of peptides having a molecular weight of 800 daltons or less, and the hydrolysates having the following composition of each of the amino acids relative to the total amino acids: an aspartic acid content in the range of 6.0 to 9.0% by weight, preferably 7.3 to 8.2% by weight; 4 0-6.0% by weight, preferably 4.6-5.3% by weight, threonine content; 10.0-15.0% by weight, preferably 11.9-13.0% by weight, serine content; 9.0-14.0% by weight, preferably 11.0-11.9% by weight, glutamic acid content; 7.0-10.0% by weight, preferably 8.4-9.1% by weight, glycine content; 4.0-6.0% by weight, preferably 5.2-5.5% by weight, alanine content; 6.0-10.0% by weight, preferably 7.8-8.5% by weight Valine content in the range of %; methionine content in the range of 0.0 to 0.5 wt%, preferably 0.1 to 0.4 wt%; isoleucine content in the range of 4.0 to 6.0 wt%, preferably 4.1 to 4.6 wt%; leucine content in the range of 6.0 to 9.0 wt%, preferably 6.7 to 7.7 wt%; tyrosine content in the range of 0.0 to 0.6 wt%, preferably 0.1 to 0.5 wt%; phenylalanine content in the range of 2.0 to 3.2 wt%, preferably 2.3 to 3.0 wt%; 1.0 to 3.0 wt%, preferably The formula has a lysine content in the range of 1.7 to 2.3% by weight, a histidine content in the range of 0.4 to 1.0% by weight, preferably 0.5 to 0.8% by weight, an arginine content in the range of 5.0 to 8.0% by weight, preferably 5.5 to 6.8% by weight, a proline content in the range of 9.0 to 14.0% by weight, preferably 9.5 to 11.8% by weight, a tryptophan content of less than 0.1% by weight, preferably equal to 0.0% by weight, and a cystine content in the range of 4.0 to 7.2% by weight, preferably 5.3 to 6.3% by weight.

2. The use according to claim 1, comprising a daily administration of 0.3 to 0.7 g of hydrolysate, preferably 0.4 to 0.6 g of hydrolysate, and in a preferred embodiment, 0.5 g of hydrolysate.

3. The use according to claim 1 or 2, characterized in that the hydrolysate is administered in the form of a composition comprising the hydrolysate and at least one component selected from the group formed by zinc or a salt thereof, copper or a salt thereof, vitamins B, particularly B3, B5, B6 and / or B8, vitamin D3, vitamin C, vitamin A, vitamin E, silicon, selenium, magnesium, calcium, manganese, molybdenum, iron, yeast, plant extracts, particularly horsetail, β-carotene, collagen, hyaluronic acid, glutathione, and mixtures thereof.

4. The use according to any one of claims 1 to 3, characterized in that the hydrolysate is administered in the form of a composition comprising the hydrolysate and at least one of the following additional amino acids: additional cystine and / or additional arginine and / or additional proline and / or additional lysine and / or additional methionine, wherein preferably the amount of additional cystine by weight is equal to the amount of cystine by weight of the hydrolysate, and / or the amount of additional arginine by weight is equal to the amount of arginine in the hydrolysate, and / or the amount of additional proline by weight is equal to the amount of proline in the hydrolysate, and / or the amount of additional lysine by weight is equal to the amount of lysine in the hydrolysate, and / or the amount of additional methionine by weight is 10 mg / day to 80 mg / day.

5. The use according to any one of claims 1 to 4, which improves the luster and / or firmness of the skin and / or reduces the loss of elasticity of the skin.

6. Use according to any one of claims 1 to 4, to prevent and / or reduce the appearance of signs of skin aging, particularly wrinkles and / or fine lines.

7. A non-therapeutic cosmetic treatment method for improving skin quality and / or appearance, comprising at least one step of oral administration of the hydrolyzed keratin Content; threonine content in the range of 4.0 to 6.0% by weight, preferably 4.6 to 5.3% by weight; serine content in the range of 10.0 to 15.0% by weight, preferably 11.9 to 13.0% by weight; glutamic acid content in the range of 9.0 to 14.0% by weight, preferably 11.0 to 11.9% by weight; glycine content in the range of 7.0 to 10.0% by weight, preferably 8.4 to 9.1% by weight; alanine content in the range of 4.0 to 6.0% by weight, preferably 5.2 to 5.5% by weight; 6.0 to 10.0% by weight, preferably 7.8 to 8.5% by weight Valine content in the range of %; methionine content in the range of 0.0 to 0.5% by weight, preferably 0.1 to 0.4% by weight; isoleucine content in the range of 4.0 to 6.0% by weight, preferably 4.1 to 4.6% by weight; leucine content in the range of 6.0 to 9.0% by weight, preferably 6.7 to 7.7% by weight; tyrosine content in the range of 0.0 to 0.6% by weight, preferably 0.1 to 0.5% by weight; phenylalanine content in the range of 2.0 to 3.2% by weight, preferably 2.3 to 3.0% by weight; 1.0 to 3.0% by weight, preferably 1 A cosmetic treatment method comprising: a lysine content in the range of 7 to 2.3% by weight; a histidine content in the range of 0.4 to 1.0% by weight, preferably 0.5 to 0.8% by weight; an arginine content in the range of 5.0 to 8.0% by weight, preferably 5.5 to 6.8% by weight; a proline content in the range of 9.0 to 14.0% by weight, preferably 9.5 to 11.8% by weight; a tryptophan content of less than 0.1% by weight, preferably equal to 0.0% by weight; and a cystine content in the range of 4.0 to 7.2% by weight, preferably 5.3 to 6.3% by weight.

8. A cosmetic treatment method according to claim 7, comprising daily administration of a hydrolyzed substance in an amount of 0.3 to 0.7 g, preferably 0.4 to 0.6 g, and in a preferred embodiment, 0.5 g of the hydrolyzed substance.

9. The cosmetic treatment method according to claim 7 or 8, wherein the hydrolysate is administered in the form of a composition comprising the hydrolysate and at least one component selected from the group formed by zinc or a salt thereof, copper or a salt thereof, vitamins B, particularly B3, B5, B6 and / or B8, vitamin D3, vitamin C, vitamin A, vitamin E, silicon, selenium, magnesium, calcium, manganese, molybdenum, iron, yeast, plant extracts, particularly horsetail, β-carotene, collagen, hyaluronic acid, glutathione, and mixtures thereof.

10. A cosmetic treatment method according to any one of claims 7 to 9, wherein the hydrolysate is administered in the form of a composition comprising the hydrolysate and at least one of the following additional amino acids: additional cystine and / or additional arginine and / or additional proline and / or additional lysine and / or additional methionine, wherein preferably the amount of additional cystine by weight is equal to the amount of cystine by weight of the hydrolysate, and / or the amount of additional arginine by weight is equal to the amount of arginine in the hydrolysate by weight, and / or the amount of additional proline by weight is equal to the amount of proline in the hydrolysate by weight, and / or the amount of additional lysine by weight is equal to the amount of lysine in the hydrolysate by weight, and / or the amount of additional methionine by weight is in the range of 10 mg / day to 80 mg / day.

11. A cosmetic treatment method according to any one of claims 7 to 10, which prevents and / or reduces the appearance of signs of skin aging, particularly wrinkles and / or fine lines, and / or improves the luster and / or firmness of the skin and / or reduces the loss of elasticity of the skin.

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