Modified methylsilanol mannuronate as well as preparation method and application thereof

Abstract

The invention provides modified methylsilanol mannuronate as well as a preparation method and application thereof. The modified methylsilanol mannuronate is prepared from the following raw materials: methylsilanol mannuronate and ulva extract. According to the modified methylsilanol mannuronate, methylsilanol mannuronate is chemically modified through the ulva extract, the modified methylsilanol mannuronate has the advantages of being high in biological activity, good in skin affinity, good in oxidation resistance and the like, and when the modified methylsilanol mannuronate is used in skin care products, compared with methylsilanol mannuronate, the modified methylsilanol mannuronate is high in effective concentration, good in anti-aging effect and free of side effects. The effect and the safety of the skin care product are obviously improved.

Description

Technical Field

[0001] The invention belongs to the technical field of skin care products, and particularly relates to a modified methylsilanol mannuronate, a preparation method and an application thereof. Background Art

[0002] Skin aging is a relatively long and complex process, and its main clinical manifestations are skin sagging, poor elasticity, wrinkles, rough surface, dryness, etc. Skin aging is divided into endogenous aging and exogenous aging. Endogenous aging refers to the aging process that occurs as the human body's own metabolic capacity gradually decreases with age. For example, the decline in the function of the skin's appendages leads to dry skin, resulting in dry lines and peeling. The slowdown in skin metabolism leads to poor moisturizing effects, which in turn leads to poor skin elasticity and wrinkles. The increase in superoxide free radicals will trigger lipid peroxidation in the body, accelerating the aging process of the skin. Exogenous aging refers to the aging changes caused by environmental factors, such as long-term exposure to ultraviolet radiation, harsh climate and environment, or long-term bad living habits and excessive work pressure. Long-term exposure to cold and dry climates will cause the skin to lack moisture and accelerate skin aging. Excessive exposure to the sun will cause excessive oxidation of the skin, which will cause skin aging.

[0003] With the improvement of living standards, people pay more and more attention to skin care and have higher requirements for the efficacy of skin care products. In order to achieve the anti-aging effect, antioxidant components, anti-glycation components or moisturizing components are usually added to skin care products; for example, methylsilanol mannuronate with antioxidant function is added to skin care products. However, the active concentration of methylsilanol mannuronate in skin care products is low, the actual effect is not obvious, the synergistic effect is poor, and it is difficult to achieve the expected effect.

[0004] Therefore, it is an urgent problem to be solved in the art to develop a modified methylsilanol mannuronate with high biological activity, good skin affinity, good antioxidant performance, high effective concentration for use in skin care products, good anti-aging effect, and the ability to significantly improve the efficacy and safety of skin care products. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide a modified methylsilanol mannuronate and a preparation method and application thereof. The modified methylsilanol mannuronate has high biological activity, good skin affinity and good antioxidant performance. Compared with methylsilanol mannuronate, it has a high effective concentration and good anti-aging effect when used in skin care products, which significantly improves the efficacy and safety of skin care products.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a modified methylsilanol mannuronate, wherein the raw materials for preparing the modified methylsilanol mannuronate include methylsilanol mannuronate and Ulva extract.

[0008] Methylsilanol mannuronate has antioxidant effects, stimulates cell renewal and collagen production, and improves the skin's ability to resist ultraviolet rays and external damage; Ulva extract has the effects of moisturizing, improving skin firmness and elasticity, and is highly safe; by using Ulva extract to chemically modify methylsilanol mannuronate, the two are synergistically enhanced to obtain modified methylsilanol mannuronate with good antioxidant properties, which can be used in skin care products to effectively improve the anti-aging properties of skin care products and have good safety.

[0009] Preferably, the mass ratio of the methylsilanol mannuronate to the Ulva extract is (0.3-0.9):1, wherein the specific value in (0.3-0.9) can be, for example, 0.3, 0.32, 0.34, 0.36, 0.38, 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, 0.52, 0.54, 0.56, 0.58, 0.6, 0.62, 0.64, 0.66, 0.68, 0.7, 0.72, 0.74, 0.76, 0.78, 0.8, 0.82, 0.84, 0.86, 0.88, 0.9, etc.

[0010] Preferably, the raw materials for preparing the methylsilanol mannuronate include brown algae and methylsilanol.

[0011] Preferably, the mass ratio of the brown algae to methylsilanol is (2-8):1, wherein the specific values ​​in (2-8) can be, for example, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, etc.

[0012] Preferably, the methylsilanol mannuronate is prepared by the following method, which comprises the following steps:

[0013] The brown algae, the solvent and the enzymolysis agent are mixed to carry out an enzymolysis reaction to obtain an enzymolysis product; the enzymolysis product is reacted with methylsilanol to obtain the methylsilanol mannuronate.

[0014] Preferably, the solvent comprises water.

[0015] Preferably, the mass of the solvent is 15 to 25 times the mass of the brown algae, for example, it can be 15 times, 16 times, 17 times, 18 times, 19 times, 20 times, 21 times, 22 times, 23 times, 24 times, 25 times, etc.

[0016] Preferably, the enzymatic agent comprises brown algae lyase.

[0017] Preferably, based on the total weight percentage of brown algae, solvent and enzymolysis agent as 100%, the added amount of the enzymolysis agent is 0.1-0.5%, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5% and the like.

[0018] Preferably, the temperature of the enzymatic hydrolysis reaction is 25-30°C, for example, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, etc.; the pH value is 6.8-7.2, for example, 6.8, 6.9, 7, 7.1, 7.2, etc.

[0019] Preferably, the number average molecular weight of the enzymatic hydrolysis product is 150-250, for example, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 210, 220, 230, 240, 250, etc.

[0020] Preferably, after the enzymatic hydrolysis reaction is completed, the method further comprises the step of eliminating the enzymatic agent.

[0021] Preferably, the temperature for eliminating the enzymatic agent is 80-90°C, for example, 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, etc.; the time is 20-40min, for example, 20min, 22min, 25min, 28min, 30min, 32min, 35min, 38min, 40min, etc.

[0022] Preferably, the temperature for the reaction of the enzymatic hydrolysate with methylsilanol is 140-160°C, for example, 140°C, 142°C, 145°C, 148°C, 150°C, 152°C, 155°C, 158°C, 160°C, etc.; the pH value is 2-3, and the time is 60-180min, for example, 60min, 65min, 70min, 80min, 90min, 100min, 110min, 120min, 130min, 140min, 150min, 160min, 170min, 180min, etc.

[0023] Preferably, the Ulva extract is prepared by the following method, which comprises:

[0024] The ulvae are mixed with an alkaline aqueous solution and subjected to a hydrolysis reaction to obtain the ulvae extract.

[0025] Preferably, the alkaline aqueous solution comprises an aqueous sodium hydroxide solution and / or an aqueous potassium hydroxide solution.

[0026] Preferably, the mass of the alkaline aqueous solution is 5 to 15 times the mass of Ulva, for example, it can be 5 times, 6 times, 7 times, 8 times, 9 times, 10 times, 11 times, 12 times, 13 times, 14 times, 15 times, etc.

[0027] Preferably, the hydrolysis reaction temperature is 90-120°C, for example, 90°C, 100°C, 110°C, 120°C, etc.; the time is 2-10h, for example, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, etc.

[0028] In a second aspect, the present invention provides a method for preparing the modified methylsilanol mannuronate according to the first aspect, the preparation method comprising the following steps:

[0029] The modified methylsilanol mannuronate is obtained by reacting methylsilanol mannuronate with ulvae extract.

[0030] Preferably, the reaction temperature is 40-50°C, for example, 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, etc.

[0031] Preferably, the pH value of the reaction is 4.5 to 5.5, for example, it can be 4.5, 4.6, 4.7, 4.8, 4.9, 5, 5.1, 5.2, 5.3, 5.4, 5.5, etc.

[0032] In the present invention, after the reaction is completed, a centrifugal filtration step is also included.

[0033] In a third aspect, the present invention provides a skin care product, comprising the modified methylsilanol mannuronate according to the first aspect.

[0034] Preferably, the skin care product comprises, by mass percentage, 10-30% modified methylsilanol mannuronate (for example, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, etc.), 0.5-1.5% glycerol glucoside (for example, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, etc.), 0.1-1% D-panthenol (for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc.), 0.01-0.05% sodium hyaluronate (for example, 0.01%, 0.02%, , 0.03%, 0.04%, 0.05%, etc.), 1-10% glycerol (for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.), 0.1-1% betaine (for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc.), 0.1-0.5% trehalose (for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc.), 0.05-0.2% tocopherol acetate (for example, 0.05%, 0.06%, 0.08%, 0.1%, 0.11%, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, etc.), 0.1-1% PEG-40 ricinoleate (for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc.), 0.01-0.05% palmitoyl tripeptide-5 (for example, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, etc.), 0.05-0.2% xanthan gum (for example, 0.05%, 0.06%, 0.08%, 0.1%, 0.11%, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, etc.), 0.2-1.2% 1,2-hexanediol (for example, it can be 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.2%, etc.), 0.1-1% p-hydroxyacetophenone (for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc.) and 45-88% water (for example, it can be 45%, 46%, 48%, 50%, 52%, 55%, 58%, 60%, 62%, 65%, 68%, 70%, 72%, 75%, 78%, 80%, 82%, 85%, 88%, etc.).

[0035] In the present invention, the preparation method of the skin care product comprises: after mixing xanthan gum, sodium hyaluronate and glycerol, adding water thereto to dissolve them to obtain solution A; dissolving 1,2-hexanediol and p-hydroxyacetophenone under heating conditions and mixing them uniformly, adding them to solution A, mixing tocopherol acetate and PEG-40 ricinoleate and adding them to solution A, then adding modified methylsilanol mannuronate, D-panthenol, betaine, trehalose and palmitoyl tripeptide-5, stirring uniformly, and obtaining the skin care product.

[0036] In the present invention, the skin care products include but are not limited to essence.

[0037] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The modified methylsilanol mannuronate provided by the present invention is prepared by chemically modifying the methylsilanol mannuronate with an Ulva extract, and the two synergistically enhance each other, thereby increasing the active concentration and enhancing the antioxidant performance. The modified methylsilanol mannuronate is used in skin care products, can effectively improve the anti-aging performance of the skin care products, and has good safety. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0041] Example 1

[0042] This embodiment provides a modified methylsilanol mannuronate, the preparation raw materials of which include methylsilanol mannuronate and Ulva extract in a mass ratio of 0.6:1; the preparation raw materials of the methylsilanol mannuronate include brown algae and methylsilanetriol in a mass ratio of 5:1.

[0043] This embodiment provides a method for preparing modified methylsilanol mannuronate, which specifically comprises the following steps:

[0044] (1) Natural marine brown algae and water (the mass of the water is 19 times the mass of the natural marine brown algae) are mixed, and brown algae lyase (Nanning Hanhe Biological Company, the mass is 0.5% of the total mass of the reaction raw materials) is added, and enzymolysis is carried out at a temperature of 25°C and a pH value of 7.0±0.2 for 4 hours. The enzymolysis is terminated when the average molecular weight of the sample is tested by electrophoresis at about 200, and then the temperature is raised to 85°C and kept warm for 30 minutes to inactivate the enzyme, and then methylsilanetriol is added in a formula amount, and the pH value is adjusted to between 2 and 3, and then heated to 150°C, and a condensation reflux device is turned on for reflux reaction for 120 minutes, and the temperature is lowered to 45°C to obtain methylsilanol mannuronate.

[0045] (2) natural ulva is mixed with 60 g / L sodium hydroxide aqueous solution in a mass ratio of 1:9, heated to 100° C. and kept warm for 4 h until the ulva is completely hydrolyzed, and then cooled to 45° C. to obtain a ulva extract; the ulva extract is reacted with the methylsilanol mannuronate obtained in step (1) at 45° C. and pH 5 for 3 h, a sample is taken and dissolved in water, and after a uniform liquid state with good water solubility is formed, the reaction is terminated to obtain modified methylsilanol mannuronate.

[0046] Example 2

[0047] This embodiment provides a modified methylsilanol mannuronate, the preparation raw materials of which include methylsilanol mannuronate and Ulva extract in a mass ratio of 0.55:1; the preparation raw materials of the methylsilanol mannuronate include brown algae and methylsilanetriol in a mass ratio of 4:1.

[0048] This embodiment provides a method for preparing modified methylsilanol mannuronate, which specifically comprises the following steps:

[0049] (1) Natural marine brown algae and water (the mass of the water is 16 times the mass of the natural marine brown algae) are mixed, and brown algae lyase (Nanning Hanhe Biological Company, the mass is 0.3% of the total mass of the reaction raw materials) is added, and the enzymatic hydrolysis is carried out at a temperature of 30°C and a pH value of 7.0±0.2 for 3.5 hours. The enzymatic hydrolysis is terminated when the average molecular weight of the sample is tested by electrophoresis at about 200, and then the temperature is raised to 90°C and kept warm for 20 minutes to inactivate the enzyme, and then methylsilanetriol is added in a formula amount, and the pH value is adjusted to between 2 and 3, and then heated to 155°C, and a condensation reflux device is turned on for reflux reaction for 130 minutes, and the temperature is lowered to 40°C to obtain methylsilanol mannuronate.

[0050] (2) natural ulva is mixed with 60 g / L sodium hydroxide aqueous solution in a mass ratio of 1:12, heated to 120° C. and kept warm for 3 h until the ulva is completely hydrolyzed, and then cooled to 40° C. to obtain an ulva extract; the ulva extract is reacted with the methylsilanol mannuronate obtained in step (1) at 40° C. and pH 5.5 for 5 h, a sample is taken and dissolved in water, and after a uniform liquid state with good water solubility is formed, the reaction is terminated to obtain modified methylsilanol mannuronate.

[0051] Example 3

[0052] This embodiment provides a modified methylsilanol mannuronate, the preparation raw materials of which include methylsilanol mannuronate and Ulva extract in a mass ratio of 0.8:1; the preparation raw materials of the methylsilanol mannuronate include brown algae and methylsilanetriol in a mass ratio of 6:1.

[0053] This embodiment provides a method for preparing modified methylsilanol mannuronate, which specifically comprises the following steps:

[0054] (1) Natural marine brown algae and water (the mass of the water is 22 times the mass of the natural marine brown algae) are mixed, and brown algae lyase (Nanning Hanhe Biological Company, the mass is 0.1% of the total mass of the reaction raw materials) is added, and enzymolysis is carried out at a temperature of 28°C and a pH value of 7.0±0.2 for 4.5 hours. The enzymolysis is terminated when the average molecular weight of the sample is tested by electrophoresis at about 200, and then the temperature is raised to 80°C and kept warm for 40 minutes to inactivate the enzyme, and then methylsilanol is added in a formula amount, and the pH value is adjusted to between 2 and 3, and then heated to 145°C, and a condensation reflux device is turned on to reflux for 150 minutes, and then the temperature is lowered to 45°C to obtain methylsilanol mannuronate.

[0055] (2) natural ulva is mixed with 60 g / L sodium hydroxide aqueous solution in a mass ratio of 1:8, heated to 90° C. and kept warm for 6 h until the ulva is completely hydrolyzed, and then cooled to 45° C. to obtain an ulva extract; the ulva extract is reacted with the methylsilanol mannuronate obtained in step (1) at 50° C. and pH 4.5 for 2 h, a sample is taken and dissolved in water, and after a uniform liquid state with good water solubility is formed, the reaction is terminated to obtain modified methylsilanol mannuronate.

[0056] Example 4

[0057] This embodiment provides a modified methylsilanol mannuronate, which differs from Example 1 only in that the mass of the Ulva extract is reduced so that the mass ratio of methylsilanol mannuronate to the Ulva extract is 1.1:1, and the other raw materials, amounts and preparation methods are the same as those in Example 1.

[0058] Example 5

[0059] This embodiment provides a modified methylsilanol mannuronate, which differs from Example 1 only in that the mass of the Ulva extract is increased so that the mass ratio of methylsilanol mannuronate to the Ulva extract is 0.1:1, and other raw materials, amounts and preparation methods are the same as those in Example 1.

[0060] Example 6

[0061] This embodiment provides a modified methylsilanol mannuronate, which differs from Embodiment 1 only in that, in the preparation method, step (2) is reacted at 45° C. and pH 7, and other raw materials, amounts and preparation methods are the same as those in Embodiment 1.

[0062] Example 7

[0063] This embodiment provides a modified methylsilanol mannuronate, which differs from Embodiment 1 only in that, in the preparation method, step (2) is reacted at 45° C. and a pH value of 3.5, and other raw materials, amounts used and preparation methods are the same as those in Embodiment 1.

[0064] Comparative Example 1

[0065] This comparative example provides a methylsilanol mannuronate, which is the methylsilanol mannuronate obtained in step (1) of Example 1.

[0066] Application Example 1

[0067] This application example provides a skin care product, which includes, by mass percentage, 20% modified methylsilanol mannuronate (Example 1), 1% glyceryl glucoside, 0.5% D-panthenol, 0.03 sodium hyaluronate, 5% glycerol, 0.5% betaine, 0.3% trehalose, 0.1% tocopheryl acetate, 0.5% PEG-40 ricinoleate, 0.03% palmitoyl tripeptide-5, 0.1% xanthan gum, 0.7% 1,2-hexanediol, 0.5% p-hydroxyacetophenone, and the balance is water.

[0068] This application example provides a method for preparing the skin care product, which specifically comprises the following steps:

[0069] After xanthan gum, sodium hyaluronate and glycerol are mixed, water is added thereto to dissolve them to obtain solution A; 1,2-hexanediol and p-hydroxyacetophenone are heated to 60° C. to dissolve and mix evenly, and then added to solution A; tocopherol acetate and PEG-40 ricinoleate are mixed and added to solution A; then modified methylsilanol mannuronate, D-panthenol, betaine, trehalose and palmitoyl tripeptide-5 are added, and the mixture is stirred evenly to obtain the skin care product.

[0070] Application Examples 2 to 7

[0071] Application Examples 2 to 7 respectively provide a skin care product, which differs from Application Example 1 only in that the modified methylsilanol mannuronate is provided by Examples 2 to 7 respectively, and the other components, dosages and preparation methods are the same as those in Application Example 1.

[0072] Comparative application example 1

[0073] This comparative application example provides a skin care product, which differs from Application Example 1 only in that the modified methylsilanol mannuronate is replaced by an equal mass of methylsilanol mannuronate provided in Comparative Example 1, and the other components, amounts and preparation methods are the same as those in Application Example 1.

[0074] Comparative Application Example 2

[0075] This comparative application example provides a skin care product, which differs from Application Example 1 only in that the modified methylsilanol mannuronate is replaced with an equal mass of the Ulva extract provided in Example 1, and the other components, dosages and preparation methods are the same as those in Application Example 1.

[0076] Comparative Application Example 3

[0077] This comparative application example provides a skin care product, which differs from Application Example 1 only in that the modified methylsilanol mannuronate is replaced by a mixture of equal masses of methylsilanol mannuronate and Ulva extract (the mass ratio of the two is 0.6:1), and the other components, amounts and preparation methods are the same as those in Application Example 1.

[0078] Performance Testing

[0079] Antioxidant activity: The test was conducted according to the in vitro DHHP free radical quenching test method in the national standard GB / T 39100-2020 "Determination of Antioxidant Activity of Peptides—DPPH and ABTS Method". 5.0 g of the skin care products obtained from the application example and the comparative application example were weighed as samples, and 2.0 mL of 1.52×10 -4 mmol / L DPPH anhydrous ethanol solution was fully mixed, and allowed to stand at room temperature in the dark for 30 minutes. The solvent was used as a blank control, and the absorbance A1 was measured at 517nm; the same volume of solvent was used to replace the sample solution as a negative control, and the absorbance A2 was measured; the same volume of anhydrous ethanol was used to replace the DPPH solution as a blank group, and the absorbance A3 was measured. Each group was repeated 3 times, and the average value was calculated. The clearance rate was calculated as follows: The clearance rate of the sample for DPPH (%) = [1-(A1-A3) / A2] × 100%. The clearance rate of the sample for DPPH free radicals (%) was used to express the antioxidant activity.

[0080] The specific test results are shown in Table 1.

[0081] Table 1

[0082] DPPH free radical scavenging rate (%) Application Example 1 90 Application Example 2 88 Application Example 3 89 Application Example 4 80 Application Example 5 77 Application Example 6 72 Application Example 7 71 Comparative application example 1 40 Comparative Application Example 2 55 Comparative Application Example 3 70

[0083] As shown in Table 1, the modified methylsilanol mannuronate obtained in the embodiment of the present invention can impart good antioxidant activity to skin care products; the scavenging rate of DPPH free radicals can reach more than 70%, and even 90%.

[0084] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A modified methylsilanol mannuronate, characterized in that: The raw materials for preparing the modified methylsilanol mannuronate include methylsilanol mannuronate and ulvae extract.

2. The modified methylsilanol mannuronate according to claim 1, characterized in that The mass ratio of the methylsilanol mannuronate to the Ulva extract is (0.3-0.9):

1.

3. The modified methylsilanol mannuronate according to claim 1 or 2, characterized in that: The raw materials for preparing the methylsilanol mannuronate include brown algae and methylsilanol; Preferably, the mass ratio of the brown algae to methylsilanol is (2-8):

1.

4. The modified methylsilanol mannuronate according to any one of claims 1 to 3, characterized in that The methylsilanol mannuronate is prepared by the following method, which comprises the following steps: Mixing brown algae, a solvent and an enzymolysis agent to perform an enzymolysis reaction to obtain an enzymolysis product; reacting the enzymolysis product with methylsilanol to obtain the methylsilanol mannuronate; Preferably, the solvent comprises water; Preferably, the mass of the solvent is 15 to 25 times the mass of the brown algae; Preferably, the enzymatic agent comprises brown algae lyase; Preferably, based on the total weight percentage of brown algae, solvent and enzymolysis agent as 100%, the added amount of the enzymolysis agent is 0.1-0.5%.

5. The modified methylsilanol mannuronate according to claim 4, characterized in that The temperature of the enzymatic hydrolysis reaction is 25-30°C, and the pH value is 6.8-7.2; Preferably, the enzymatic hydrolysis reaction is carried out to a number average molecular weight of the enzymatic hydrolysis product of 150 to 250; Preferably, after the enzymatic hydrolysis reaction is completed, the method further comprises the step of eliminating the enzymatic agent; Preferably, the temperature for eliminating the enzymatic agent is 80-90°C and the time is 20-40 minutes; Preferably, the temperature for the reaction of the enzymatic hydrolysis product with methylsilanol is 140-160° C., the pH value is 2-3, and the reaction time is 60-180 min.

6. The modified methylsilanol mannuronate according to any one of claims 1 to 5, characterized in that The Ulva extract is prepared by the following method, which comprises: Mixing ulvae with an alkaline aqueous solution and performing a hydrolysis reaction to obtain the ulvae extract; Preferably, the alkaline aqueous solution comprises an aqueous sodium hydroxide solution and / or an aqueous potassium hydroxide solution; Preferably, the mass of the alkaline aqueous solution is 5 to 15 times the mass of Ulva; Preferably, the temperature of the hydrolysis reaction is 90-120° C., and the time is 2-10 hours.

7. A method for preparing the modified methylsilanol mannuronate according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: The modified methylsilanol mannuronate is obtained by reacting methylsilanol mannuronate with ulvae extract.

8. The preparation method according to claim 7, characterized in that: The reaction temperature is 40-50°C; Preferably, the pH value of the reaction is 4.5-5.

5.

9. A skin care product, characterized in that: The skin care product comprises the modified methylsilanol mannuronate according to any one of claims 1 to 6.

10. The skin care product according to claim 9, characterized in that: Calculated by mass percentage, the skin care product includes 10-30% modified methylsilanol mannuronate, 0.5-1.5% glyceryl glucoside, 0.1-1% D-panthenol, 0.01-0.05% sodium hyaluronate, 1-10% glycerol, 0.1-1% betaine, 0.1-0.5% trehalose, 0.05-0.2% tocopherol acetate, 0.1-1% PEG-40 ricinoleate, 0.01-0.05% palmitoyl tripeptide-5, 0.05-0.2% xanthan gum, 0.2-1.2% 1,2-hexanediol, 0.1-1% p-hydroxyacetophenone and 45-88% water.