Application of hyaluronic acid in preparing a preparation for promoting the production of keratin CK15

Abstract

The present invention discloses the application of hyaluronic acid in the preparation of a preparation for promoting the production of keratin CK15, belonging to the technical field of dermatology; the application of hyaluronic acid in the preparation of a preparation for promoting the production of keratin CK15 provided by the present invention, as confirmed by the experiments of the present invention, hyaluronic acid within a specific polydispersity coefficient and viscosity-average molecular weight range can effectively promote the production of keratin CK15; when applied to a composition, it can better play the role of promoting the production of keratin CK15 on the basis of meeting the applicability within a certain pH value range of the composition, achieving the promoting effect of the composition on the production of keratin CK15.

Description

Technical Field

[0001] The present invention belongs to the field of dermatology, and particularly relates to the application of hyaluronic acid in the preparation of a preparation for promoting the production of cytokeratin CK15. Background Art

[0002] Cytokeratin 15 (CK15) is a type of structural protein found in animal cells and constitutes an important part of the cytoskeleton. These proteins contribute to cell shape maintenance, mechanical strength, and intracellular signal transduction. CK15 is a member of the cytokeratin family and is mainly expressed in the skin, hair follicles, and other structures. In the skin, this protein is usually located in the basal cells, which are an important source for skin regeneration and maintaining skin integrity. The expression of CK15 in stem cells and basal cells is crucial for maintaining the regenerative capacity of the skin. Basal cells not only provide structural support for the skin but also differentiate into other types of skin cells to promote skin renewal and repair. The presence of CK15 in these cells helps maintain their stem cell state and is involved in regulating the process of cell differentiation.

[0003] In addition, CK15 is also related to the function of hair follicles. Hair follicles are structures that produce hair, and the basal cells in them also express CK15. These basal cells play an important role in the hair growth cycle, helping to maintain hair growth and regeneration. That is, as a part of the cytokeratin family, CK15 plays a key role in skin regeneration, cell structure maintenance, and the hair growth cycle.

[0004] Hyaluronic acid is a large molecular polysaccharide first extracted and isolated from bovine vitreous humor by Professor Meyer of Columbia University in the United States in 1934, also known as hyaluronic acid. Hyaluronic acid is a transparent and viscous colloidal substance, and this amazing substance has a special water retention effect and is the best moisturizing substance found in nature at present. Hyaluronic acid is a natural biological substance widely present in tissues such as the vitreous humor of the eye, skin, umbilical cord, and synovial fluid of joints. In the early days, the raw materials of hyaluronic acid were mainly extracted from chicken combs, so due to cost and raw material limitations, it was not further promoted. Now, hyaluronic acid mainly comes from microbial fermentation production, which is not limited by animal raw materials, has a low cost, is easy to scale up production, and the product has a high purity. Most of the "hyaluronic acid" on the market exists in the form of sodium salt of hyaluronic acid and is used as a moisturizer. In recent years, the zinc salt of hyaluronic acid has begun to be applied in the skin care field, and its efficacy focuses on anti-inflammatory repair and other directions. However, hyaluronic acid itself (non-salt) has a low pH value (2.5 - 4.5) and strong acidity, while the pH value of human skin is generally 4.5 - 6.5. Therefore, its application in general neutral skin care products is limited. Even if it is added to the formula, due to the limitation of the formula pH value, it loses its efficacy under acidic conditions. Summary of the Invention

[0005] An object of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide an application of hyaluronic acid in the preparation of a preparation for promoting the production of keratin CK15.

[0006] To achieve the above object, in the first aspect of the present invention, the present invention provides an application of hyaluronic acid in the preparation of a preparation for promoting the production of keratin CK15.

[0007] The present invention has found through research that hyaluronic acid can effectively promote the production of keratin CK15. Therefore, it can be applied to the preparation of a preparation for promoting the production of keratin CK15.

[0008] As a preferred embodiment of the application of the present invention, the polydispersity coefficient of the hyaluronic acid is 4.0 - 6.5, and the viscosity-average molecular weight is 3 - 20 kDa.

[0009] The polydispersity coefficient (PD) characterizes the width of the molecular weight distribution curve, which is calculated as the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn), that is, polydispersity coefficient = weight-average molecular weight / number-average molecular weight. The viscosity-average molecular weight (Mv) is the average molecular weight measured by the solution viscosity method; the weight-average molecular weight, number-average molecular weight, and viscosity-average molecular weight can be measured by referring to the method in Patent CN108992369B.

[0010] Exemplarily, the polydispersity coefficient of the hyaluronic acid can be any point value or any two-point range value between 4.0 - 6.5, for example, it can be 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, etc.; the viscosity-average molecular weight of the hyaluronic acid can be any point value or any two-point range value between 3 - 20 kDa, for example, it can be 3 kDa, 4 kDa, 5 kDa, 6 kDa, 7 kDa, 8 kDa, 9 kDa, 10 kDa, 11 kDa, 12 kDa, 13 kDa, 14 kDa, 15 kDa, 16 kDa, 17 kDa, 18 kDa, 19 kDa, 20 kDa, etc.

[0011] As a preferred embodiment of the application of the present invention, the polydispersity coefficient of the hyaluronic acid is 4.8 - 5.9, and the viscosity-average molecular weight is 8 - 13 kDa.

[0012] The present invention has found through research that the polydispersity coefficient and the viscosity-average molecular weight of hyaluronic acid can affect the effect of keratin CK15 generation. When further selecting the polydispersity coefficient of hyaluronic acid to be 4.0 - 6.5 and the viscosity-average molecular weight to be 3 - 20 kDa, especially when the polydispersity coefficient is 4.8 - 5.9 and the viscosity-average molecular weight is 8 - 13 kDa, the obtained hyaluronic acid has a better effect in promoting keratin CK15 generation.

[0013] Preferably, the weight-average molecular weight of the hyaluronic acid is 8 - 60 kDa, and the number-average molecular weight is 2 - 9 kDa.

[0014] More preferably, the weight-average molecular weight of the hyaluronic acid is 18 - 22 kDa, and the number-average molecular weight is 3 - 5 kDa.

[0015] The weight-average molecular weight (Mw) is obtained by multiplying the weight fraction of each molecule by its corresponding molecular weight, that is, the molecular weight statistically averaged by weight; the number-average molecular weight (Mn) is the total weight of all polymer molecules in the sample divided by the total number of molecules.

[0016] The ratio of the weight-average molecular weight to the number-average molecular weight is the polydispersity coefficient. The present invention has found that when the weight-average molecular weight and the number-average molecular weight of hyaluronic acid are within the above ranges, especially within the more preferred ranges, the obtained hyaluronic acid has a more excellent effect in promoting keratin CK15.

[0017] Preferably, the pH value of a 0.1% aqueous solution of the hyaluronic acid is 2.5 - 4.5.

[0018] In the second aspect of the present invention, the present invention provides a composition for promoting keratin CK15 generation, and the composition includes hyaluronic acid.

[0019] As a preferred embodiment of the composition of the present invention, the polydispersity coefficient of the hyaluronic acid is 4.0 - 6.5, and the viscosity-average molecular weight is 3 - 20 kDa.

[0020] As a preferred embodiment of the composition of the present invention, the polydispersity coefficient of the hyaluronic acid is 4.8 - 5.9, and the viscosity-average molecular weight is 8 - 13 kDa.

[0021] Preferably, the weight-average molecular weight of the hyaluronic acid is 8 - 60 kDa, and the number-average molecular weight is 2 - 9 kDa.

[0022] More preferably, the weight-average molecular weight of the hyaluronic acid is 18 - 22 kDa, and the number-average molecular weight is 3 - 5 kDa.

[0023] The research of the present invention finds that when further selecting the polydispersity coefficient, viscosity-average molecular weight and other parameters of hyaluronic acid within the above ranges and using it as a component of the composition, the obtained composition can better promote the generation of keratin CK15.

[0024] As a preferred embodiment of the composition of the present invention, based on the composition, the mass percentage of hyaluronic acid is 0.05-0.2%.

[0025] The research of the present invention finds that adding 0.05-0.2% of hyaluronic acid to the composition can better exert the effect of promoting the generation of keratin CK15.

[0026] As a preferred embodiment of the composition of the present invention, the pH value of the composition is 4.0-5.5.

[0027] Exemplarily, the pH value of the composition can be any point value or any two-point range value between 4.0-5.5, such as 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, etc.

[0028] The research of the present invention finds that when the pH value of the composition is controlled to be 4.0-5.5, the unique efficacy characteristics of hyaluronic acid under acidic conditions can be exerted, and this pH value range is also non-irritating to human application; when the pH value is too low, there will be a certain degree of irritation, and when the pH value is too high, such as reaching about 6.0, although it presents a weak acid environment and the irritation is lower, the efficacy of the obtained composition in promoting the generation of keratin CK15 shows a downward trend; that is, the selected pH value range of the composition of the present invention can exert the optimal efficacy while meeting the requirements of skin care products.

[0029] As a preferred embodiment of the composition of the present invention, the composition further includes a skin care product matrix.

[0030] Preferably, the skin care product matrix includes at least one of water, emulsifier, surfactant, and preservative.

[0031] Preferably, by selecting different skin care product matrices, different types of compositions can be prepared, such as the composition can be a cream, essence water, essence milk, mask, gel, etc.

[0032] The research of the present invention finds that selecting different forms of skin care product matrices and compounding them with the hyaluronic acid of the present invention to form corresponding compositions can effectively promote the generation of keratin CK15, so that the obtained compositions can specifically achieve effects such as exfoliation and hair care.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] The application of hyaluronic acid provided by the present invention in the preparation of a preparation for promoting the production of keratin CK15. It has been confirmed by the experiments of the present invention that hyaluronic acid within a specific polydispersity coefficient and viscosity-average molecular weight range can effectively promote the production of keratin CK15. When applied to a composition, within a certain pH value range of the composition, it can better play the role of promoting the production of keratin CK15 on the basis of meeting applicability, achieving the promoting effect of the composition on the production of keratin CK15. Brief Description of the Drawings

[0035] Figure 1 It is the verification result graph in Effect Example 2. Detailed Embodiments

[0036] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0037] The reagents, methods and equipment used in the present invention are all conventional reagents, methods and equipment in the art unless otherwise specified.

[0038] The hyaluronic acid used in the examples and comparative examples of the present invention was prepared by fermentation and purification from Streptococcus zooepidemicus (purchased from ATCC, catalog number HA-116 ATCC 39920);

[0039] The specific method for preparing hyaluronic acid 1 is as follows:

[0040] Culture Medium

[0041] Slant medium (g / L): Brain Heart Infusion (BHI) 36 g / L, glucose 12 g / L, yeast powder 12 g / L, agar powder 24 g / L, and the pH value of the slant medium is 7.2;

[0042] Seed medium (g / L): glucose 40 g / L, yeast powder 20 g / L, magnesium sulfate heptahydrate 2.0 g / L, manganese sulfate tetrahydrate 0.1 g / L, potassium dihydrogen phosphate 2.0 g / L, calcium carbonate 20 g / L, and the pH value of the seed medium is 7.0;

[0043] Fermentation medium (g / L): yeast powder 20 g / L, disodium hydrogen phosphate 6.2 g / L, potassium sulfate 1.3 g / L, glucose 140 g / L, magnesium sulfate heptahydrate 2.0 g / L, and the pH value of the fermentation medium is 7.0.

[0044] Cultivation Method

[0045] Slant culture: The inoculated slant was placed in a constant temperature incubator at 37 ± 0.2 °C and cultured for 16 ± 0.5 h for shake flask inoculation;

[0046] Seed culture: Inoculate the well-cultured slant seeds into a 500 mL Erlenmeyer flask containing 50 mL of seed medium and culture at a shaker speed of 200 r / min, a temperature of 37 ± 0.2 °C, and a culture time of 15 h;

[0047] Fermentation culture: Inoculate the seed medium into a fully automatic fermenter KFT-7L (Biostat B 2nd generation 1000009844, Sartorius, Germany) at an inoculation amount of 10%. The fermenter is filled with 3.5 L of fermentation medium. The stirring speed is 200 ± 10 r / min, the aeration rate is 1.0 vvm, and the temperature is 37 ± 0.2 °C. Use a pH electrode to detect the pH online and adjust it by adding 5 mol / L NaOH solution through an automatic feeding pump to maintain the pH change within 7.0 ± 0.1. Use a dissolved oxygen electrode to detect the dissolved oxygen concentration online and take samples for detection and analysis every 2 h.

[0048] Extraction and purification

[0049] Take an appropriate amount of the fermentation broth and place it in a stainless steel tank (the outlet is connected to a plate and frame filter). Add water to adjust the concentration to about 0.5%. Stir the mixture at a stirring speed of 200 ± 10 r / min and a temperature of 60 °C for about 30 minutes. After mixing evenly, add 6 mol / L HCl to adjust the pH to 1.5 and continue stirring at this temperature for 8 h. Then start discharging the liquid, and the discharging time lasts for 6 h. Keep stirring in the tank during discharging. After discharging and filtering until the transmittance of the filtrate reaches 99.9% (550 nm), obtain the mixed filtrate 1 and place it in a stainless steel tank, keeping stirring at a stirring speed of 200 ± 10 r / min to obtain the mixed filtrate 2. Take the mixed filtrate 2, add 70% ethanol for precipitation, keep stirring at a stirring speed of 50 ± 5 r / min to obtain the mixed liquid 3. Take the mixed liquid 3, centrifuge for 1 hour at a speed of 4000 r / min, discard the supernatant, take the lower precipitate, dry it, turn the plate every 2 hours, take the dried sample to measure the loss on drying until it is dried to a constant weight, pulverize it, and pass through an 80-mesh sieve to obtain the product.

[0050] The parameters of hyaluronic acid 1 are: Mv = 3.0 kDa, Mw = 8.2 kDa, Mn = 2.04 kDa, PD = 4.02.

[0051] The preparation method of hyaluronic acid 2 is only different from that of hyaluronic acid 1 in extraction and purification. After adding 6 mol / L HCl to adjust the pH to 1.5, continue stirring at this temperature for 6 h, and then start discharging the liquid, and the discharging time lasts for 8 h. The parameters of the prepared hyaluronic acid 2 are: Mv = 8.1 kDa, Mw = 18.6 kDa, Mn = 3.2 kDa, PD = 5.81.

[0052] The only difference between the preparation method of hyaluronic acid 3 and hyaluronic acid 1 lies in the extraction and purification process. After adjusting the pH to 1.8 with 6 mol / L HCl, continue stirring at this temperature for 6 h, and then start discharging the liquid. The discharging time lasts for 6.5 h. The parameters of the prepared hyaluronic acid 3 are: Mv = 12.2 kDa, Mw = 21.6 kDa, Mn = 4.5 kDa, PD = 4.8.

[0053] The only difference between the preparation method of hyaluronic acid 4 and hyaluronic acid 1 lies in the extraction and purification process. After adjusting the pH to 2.0 with 6 mol / L HCl, continue stirring at this temperature for 5 h, and then start discharging the liquid. The discharging time lasts for 7 h. The parameters of the prepared hyaluronic acid 4 are: Mv = 19.9 kDa, Mw = 57.9 kDa, Mn = 8.9 kDa, PD = 6.5.

[0054] The only difference between the preparation method of hyaluronic acid 5 and hyaluronic acid 1 lies in the extraction and purification process. After adjusting the pH to 2.2 with 6 mol / L HCl, continue stirring at this temperature for 4 h, and then start discharging the liquid. The discharging time lasts for 6 h. The parameters of the prepared hyaluronic acid 5 are: Mv = 50.2 kDa, Mw = 117.6 kDa, Mn = 24.5 kDa, PD = 4.8.

[0055] The only difference between the preparation method of hyaluronic acid 6 and hyaluronic acid 1 lies in the extraction and purification process. After adjusting the pH to 1.5 with 6 mol / L HCl, continue stirring at this temperature for 9 h, and then start discharging the liquid. The discharging time lasts for 6.5 h. The parameters of the prepared hyaluronic acid 6 are: Mv = 2.1 kDa, Mw = 6.7 kDa, Mn = 1.4 kDa, PD = 4.8.

[0056] The only difference between the preparation method of hyaluronic acid 7 and hyaluronic acid 1 lies in the extraction and purification process. After adjusting the pH to 1.8 with 6 mol / L HCl, continue stirring at this temperature for 6.5 h, and then start discharging the liquid. The discharging time lasts for 3 h. The parameters of the prepared hyaluronic acid 7 are: Mv = 12.5 kDa, Mw = 17.4 kDa, Mn = 6.2 kDa, PD = 2.8.

[0057] The only difference between the preparation method of hyaluronic acid 8 and hyaluronic acid 1 lies in the extraction and purification process. After adjusting the pH to 1.8 with 6 mol / L HCl, continue stirring at this temperature for 5 h, and then start discharging the liquid. The discharging time lasts for 10 h. The parameters of the prepared hyaluronic acid 8 are: Mv = 12.8 kDa, Mw = 30.5 kDa, Mn = 3.5 kDa, PD = 8.7.

[0058] Examples and comparative examples

[0059] Embodiments and comparative examples of the present invention provide a cream, and the components (mass percentages) of the cream are shown in Table 1;

[0060] Table 1

[0061]

[0062]

[0063] The preparation method of the cream provided in Example 1 is as follows:

[0064] (1) Preparation of Phase C: Weigh hyaluronic acid, add water and stir until completely dissolved, and then adjust the pH value to between 4.0 and 5.5 with an appropriate amount of 1% sodium bicarbonate aqueous solution to obtain Phase C;

[0065] (2) Preparation of Phase A: Weigh the components in Phase A, mix them and heat to 85°C, stir evenly to obtain Phase A;

[0066] (3) Preparation of Phase B: Weigh the components in Phase B, mix them and heat to 85°C, stir evenly to obtain Phase B;

[0067] (4) Add Phase A in step (2) to Phase B in step (3), stir evenly, and then add Phase C in step (1) when the temperature is lowered to 45°C, and stir and mix evenly;

[0068] (5) Adjust the pH value to 4.8 with an appropriate amount of 1% sodium bicarbonate aqueous solution, and age to obtain the cream.

[0069] The preparation methods of the creams (placebo creams) provided in Examples 2-6, Comparative Examples 1-5 and the blank example are the same as those in Example 1, and just do not add the relevant components if they are not present.

[0070] Example 7

[0071] An embodiment of the present invention provides a cream, and the only difference between this cream and that in Example 1 is that in step (5), the pH value is adjusted to 5.4 with an appropriate amount of 1% sodium bicarbonate aqueous solution.

[0072] Example 8

[0073] An embodiment of the present invention provides a cream, and the only difference between this cream and that in Example 1 is that in step (5), the pH value is adjusted to 4.2 with an appropriate amount of 1% sodium bicarbonate aqueous solution.

[0074] Comparative Example 6

[0075] A comparative example of the present invention provides a cream, and the only difference between this cream and that in Example 1 is that in step (5), the pH value is adjusted to 6.1 with an appropriate amount of 1% sodium bicarbonate aqueous solution.

[0076] Effect Example 1

[0077] The effect example of the present invention verifies the safety of hyaluronic acid 3 aqueous solutions with different pH values or hyaluronic acid 3 aqueous solutions with different concentrations, including the following steps:

[0078] 1. Preparation of hyaluronic acid 3 aqueous solution

[0079] (1) Prepare a 1% sodium bicarbonate aqueous solution by mass percentage for later use;

[0080] (2) Weigh a certain amount of hyaluronic acid 3 (determine the mass here according to the mass percentage to be prepared, for example, if the mass percentage is 0.2%, then weigh 0.2 g of hyaluronic acid), add it to 90 g of water, stir until completely dissolved, then adjust the pH value to a fixed value with the 1% sodium bicarbonate aqueous solution in step (1), add water to make up to 100 g, and measure the final pH value.

[0081] 2. Safety test

[0082] The parameters of hyaluronic acid 3 aqueous solutions with different concentrations and pH values are shown in Table 3. The specific test process is as follows: Use hyaluronic acid 3 aqueous solutions with different concentrations and different pH values for safety tests, and set a placebo at the same time. There are 31 subjects in total, 5 males and 26 females, aged 23 - 45 years old. Select a suitable patch tester with an area not exceeding 50 mm 2 , and a depth of about 1 mm. Using the closed patch test method, add about 0.020 - 0.025 mL of the test substance to the patch tester, apply the patch tester to the back of the subject. After 24 hours, remove the test substance, observe the skin reaction 0.5 hour after removal, and record the results according to the skin reaction grading standard in the Cosmetics Safety Technical Specifications (2015 edition) (shown in Table 2). The results obtained are shown in Table 3;

[0083] Table 2

[0084]

[0085] Table 3

[0086]

[0087]

[0088] It can be seen from Table 3 that when the pH value of the hyaluronic acid aqueous solution is between 4.0 - 6.4 and the mass percentage in the hyaluronic acid aqueous solution is below 0.3%, the patch test results all show safe and non - irritating.

[0089] Effect Example 2

[0090] The present invention verifies the promoting effect of the creams (placebo creams) prepared in the effect example, comparative examples and blank example on keratin CK15, which specifically includes the following steps:

[0091] (1) Appropriate amounts of the creams (placebo creams) of Examples 1-8, Comparative Examples 1-6 and the blank example were respectively applied evenly on the prepared human ex vivo skin surface on days T0, T2, T5 and T6 until completely absorbed (the ratio of the amount of the placebo cream applied in the examples and comparative examples to the application area was kept consistent, being 0.020 - 0.025 g / cm 2 , and the human ex vivo skin was the abdominal ex vivo skin of a 56-year-old white female, with 3 skin explants in each group); in addition, a group without any treatment was set as the blank group;

[0092] (2) The measurement site was the CK15 skin stem cell marker. The anti-CK15 monoclonal antibody (Santa Cruz, ref. sc-70912) was diluted to 1:500 with a 0.05% PBS-BSA 0.3% Tween-20 solution, and the CK15 antibody was labeled with fluorescein AF594 (Life technologies, ref. A11005, red staining). The tissue was immunostained at room temperature on day T7, and the staining was observed and evaluated using a Leica DMLB microscope. Subsequently, semi-quantitative analysis was performed using the image analysis software CellSens (Olympus), and the percentage of the surface of the basal layer with positive CK15 immunostaining was calculated; the results obtained are shown in Table 4;

[0093] In the result analysis, the data are expressed as the mean, and the statistical analysis results above the error bars are reported as follows: the statistical analysis within the group (sample group vs blank group) is represented by black asterisks (*p < 0.05; **p < 0.01; ***p < 0.001), and the statistical analysis between groups (sample group vs placebo cream group) is represented by "#" (#p < 0.05; ##p < 0.01; p < 0.001);

[0094] Table 4

[0095]

[0096]

[0097] As can be seen from Table 4, when the technical solution of the present invention is adopted, the obtained cream can effectively promote the generation of keratin CK15, and the percentage of the surface with positive CK15 immunostaining is above 28.5%, which is much higher than the percentage of the positive surface in the blank group and the placebo cream group;

[0098] It can be seen from Examples 1-3 and Comparative Example 5 that the addition amount of hyaluronic acid will affect the production effect of CK15. Increasing the addition amount of hyaluronic acid within a safe range can achieve a more excellent effect of promoting the production of CK15; it can be seen from Example 1, Examples 7-8 and Comparative Example 6 that the pH value of the finally prepared cream will also affect the promotion of CK15 production by the product. When the pH value of the cream is within the range of 4.0-5.5 given in the present invention, the production of CK15 can be better promoted. When the pH value of the cream > 5.5, that is, outside the scope of the present invention, although there is no irritation, the ability to promote the production of CK15 decreases;

[0099] It can be seen from Example 1, Examples 4-6 and Comparative Examples 1-4 that the polydispersity coefficient and the viscosity-average molecular weight of hyaluronic acid will also affect the ability of the cream to promote the production of CK15. When the polydispersity coefficient or the viscosity-average molecular weight of the hyaluronic acid provided in Comparative Examples 1-4 is not within the scope of the present invention, the ability of the obtained product to promote the production of CK15 is weak; when further selecting the polydispersity coefficient of hyaluronic acid to be 4.8-5.9 and the viscosity-average molecular weight to be 8-13 kDa, the ability of the obtained product to promote the production of CK15 is excellent, and the positive surface percentage of CK15 immunostaining at T7 days is above 40.6%;

[0100] Meanwhile, Figure 1 provides the immunostaining result diagram on the 7th day during the verification process. The more obvious and clear the green fluorescence is, the more CK15 is produced. It can be seen from Figure 1 that the product provided by the technical solution of the present invention can significantly promote the production of keratin CK15 compared with the placebo cream group and the blank group.

[0101] Finally, it should be noted that the above examples are used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. Use of hyaluronic acid in the preparation of a preparation for promoting the production of keratin CK15; The polydispersity coefficient of the hyaluronic acid is 4.0 - 6.5, and the viscosity-average molecular weight is 3 - 20 kDa.

2. The application according to claim 1, wherein The polydispersity coefficient of the hyaluronic acid is 4.8 - 5.9, and the viscosity-average molecular weight is 8 - 13 kDa.

3. A composition for promoting the production of keratin CK15, characterized in that, The composition comprises hyaluronic acid; The polydispersity coefficient of the hyaluronic acid is 4.0 - 6.5, and the viscosity-average molecular weight is 3 - 20 kDa; In the composition, the mass percentage of hyaluronic acid is 0.1 - 0.2%; The pH value of the composition is 4.0 - 5.

5.

4. The composition according to claim 3, characterized in that, The polydispersity coefficient of the hyaluronic acid is 4.8 - 5.9, and the viscosity-average molecular weight is 8 - 13 kDa.

5. The composition according to claim 3, wherein The composition further comprises a skin care product matrix.

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