A kind of glycyrrhizic acid compound nanoparticles and its preparation method and application

Abstract

This invention relates to glycyrrhizic acid-based nanoparticles, their preparation method, and applications, specifically belonging to the field of nanotechnology. The preparation method of the nanoparticles is as follows: (1) Modified chitosan is completely dissolved in a 0.5-1.5 wt% acidic aqueous solution to prepare a modified chitosan aqueous solution; (2) Glycyrrhizic acid-based compounds are dissolved in a 0.5-1.5 wt% alkaline aqueous solution to prepare a glycyrrhizic acid-based aqueous solution; (3) Under stirring conditions, the modified chitosan aqueous solution from step (1) and the glycyrrhizic acid-based aqueous solution from step (2) are mixed, Tween 80 is added, and stirring is continued for 1-3 hours to obtain a glycyrrhizic acid-based nanoparticle emulsion; (4) The glycyrrhizic acid-based nanoparticle emulsion from step (3) is freeze-dried to obtain glycyrrhizic acid-based nanoparticles. The glycyrrhizic acid-based nanoparticles prepared in this invention have good stability and antioxidant properties, and can significantly reduce the influence of glycyrrhizic acid-based compounds on the viscosity of the carbomer system.

Description

Technical Field

[0001] The invention belongs to the field of nanotechnology, and specifically relates to glycyrrhizic acid compound nanoparticles and a preparation method and application thereof. Background Art

[0002] With the development of science and technology, people in modern society pay more and more attention to their appearance. In modern life, due to people's eating, working and resting habits and environmental problems, their skin will have many problems, such as acne, allergies, rapid aging or spots, which will have a great impact on people's lives and psychology. Based on these problems, the development of functional skin care products is becoming more and more widespread. Skin care products can help the skin resist external invasion, maintain the balance of skin microecology, maintain the health of the skin barrier, and repair damaged aging problems. However, many existing cosmetics have uneven effects, and more in-depth research is needed on the effective ingredients of skin care products to improve the comprehensive effect of skin care products.

[0003] Glycyrrhizic acid compounds include glycyrrhizic acid, glycyrrhetinic acid and glycyrrhizic acid salts. They are not only important in the medical industry, but also widely used in the cosmetics industry. Glycyrrhizic acid compounds are a good water-soluble cosmetic anti-allergic soothing ingredient. They can whiten the skin by scavenging free radicals and clearing inflammation. They can inhibit the production of melanocytes from the root, prevent and reduce suntan, spots and acne marks, even and brighten the skin tone, and form a barrier against ultraviolet rays on the skin. In the skin care industry, they are often used together with other surfactants to accelerate the digestion and absorption of skin care ingredients by the skin and improve quality and efficiency. They can be used for sun protection, whitening, itching, adjusting sebaceous glands, anti-allergic, freckle removal, moisturizing, etc. The addition amount of glycyrrhizic acid compounds is generally 0.1-0.8%, but when used in combination with the carbomer system, due to its own strong ionicity, the overall viscosity of the cosmetic system will be reduced, thereby limiting the use amount and application range of glycyrrhizic acid compounds, and will also have a greater impact on the overall performance of skin care products.

[0004] Based on the problems existing in the existing technology, shielding and reducing the effect of the ionicity of glycyrrhizic acid compounds on the viscosity of carbomer through special technical means is of great significance for expanding the application scope of glycyrrhizic acid compounds and improving the comprehensive performance of skin care products. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a glycyrrhizic acid compound nanoparticle and a preparation method and application thereof. The preparation process of the glycyrrhizic acid compound nanoparticle is simple, and the prepared glycyrrhizic acid compound nanoparticle has good stability and antioxidant properties, can significantly reduce the effect of glycyrrhizic acid compounds on the viscosity of the carbomer system, and expand the application of glycyrrhizic acid compounds in the field of daily chemicals.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention provides a method for preparing glycyrrhizic acid compound nanoparticles, comprising the following preparation steps:

[0008] (1) completely dissolving the modified chitosan in a 0.5-1.5 wt % acidic aqueous solution to prepare a modified chitosan aqueous solution;

[0009] (2) completely dissolving the glycyrrhizic acid compound in a 0.5-1.5 wt % alkaline aqueous solution to prepare a glycyrrhizic acid compound aqueous solution;

[0010] (3) under stirring, mixing the modified chitosan aqueous solution obtained in step (1) and the glycyrrhizic acid compound aqueous solution obtained in step (2) to obtain a mixed solution, adding Tween 80 thereto, and continuing stirring for 1-3 hours to obtain a glycyrrhizic acid compound nanoparticle emulsion;

[0011] (4) freeze-drying the glycyrrhizic acid compound nanoparticle emulsion obtained in step (3) to obtain glycyrrhizic acid compound nanoparticles.

[0012] The present invention uses chitosan grafted with epicatechin gallate, and by strictly controlling the preparation process, glycyrrhizic acid compounds are prepared into nanoparticles with uniform particle size. The nanoparticles have good stability and antioxidant properties, and can significantly reduce the effect of glycyrrhizic acid compounds on the viscosity of the carbomer system. The nanoparticles are used in skin care products to make the ingredients of the skin care products more stable and improve the anti-inflammatory and antioxidant properties of the skin.

[0013] In some embodiments, the preparation steps of the modified chitosan are:

[0014] Chitosan and epicatechin gallate were dissolved in an acetic acid solution, stirred for 20-30 minutes to obtain a mixed solution, ascorbic acid was added to the mixed solution, an inert gas was introduced for 50-60 minutes, an initiator was added, and the mixture was reacted at 20-25° C. in an inert gas atmosphere for 20-24 hours, and finally dialyzed in deionized water for 65-75 hours, and freeze-dried to obtain modified chitosan.

[0015] The invention strictly controls the preparation process during the modification of chitosan, and grafts epicatechin gallate onto the hydroxyl group and the amino group of chitosan through a free radical-mediated reaction generated by ascorbic acid and an initiator. The grafting rate is high, and the influence of glycyrrhizic acid compounds on the viscosity of the carbomer system can be significantly reduced. The prepared modified chitosan has good defense performance and antioxidant capacity against ultraviolet light, and the application of the modified chitosan in skin care products can significantly improve the efficacy of the skin care products.

[0016] In some embodiments, the mass ratio of chitosan, epicatechin gallate and ascorbic acid is 1:(1-2):(0.1-0.12).

[0017] Preferably, the mass ratio of chitosan, epicatechin gallate and ascorbic acid is 1:1.5:0.11.

[0018] In some embodiments, the mass concentration of the chitosan in the acetic acid solution is 0.5-3%.

[0019] Preferably, the mass concentration of the chitosan in the acetic acid solution is 1%.

[0020] The applicant found that by strictly controlling the mass ratio of chitosan, epicatechin gallate and ascorbic acid and the concentration of chitosan in the system, the grafting rate of epicatechin gallate on chitosan can be increased, further improving its antioxidant capacity.

[0021] In some embodiments, the chitosan has a deacetylation degree of ≥90% and a Mw of 200,000-500,000.

[0022] The applicant found that chitosan with a deacetylation degree of ≥90% has good water solubility and appropriate viscosity. Using this characteristic chitosan can increase the grafting rate of epicatechin gallate on chitosan. This is because epicatechin gallate has a higher affinity with this specific chitosan, thereby improving its grafting rate and antioxidant capacity.

[0023] In some embodiments, the initiator is one or more of ammonium persulfate, potassium persulfate and hydrogen peroxide.

[0024] Preferably, the initiator is ammonium persulfate.

[0025] In some embodiments, the glycyrrhizic acid compound in the mixed solution is 15-35 wt % of the modified chitosan.

[0026] Preferably, the glycyrrhizic acid compound in the mixed solution is 25wt% of the modified chitosan.

[0027] More preferably, the glycyrrhizic acid compound is glycyrrhizic acid and glycyrrhizic acid salt.

[0028] The applicant has found that strictly controlling the amount of glycyrrhizic acid compound added can improve the encapsulation rate of the modified chitosan for the glycyrrhizic acid compound and make the particle size of the prepared glycyrrhizic acid compound nanoparticles uniform and moderate.

[0029] In some embodiments, the amount of Tween 80 added is 1-3 wt % of the mixed solution.

[0030] Preferably, the amount of Tween 80 added is 2 wt % of the mixed solution.

[0031] The applicant found that the nanoparticles generated by the reaction in the present application are prone to agglomeration. A certain amount of Tween 80 is added to the reaction system, which can not only adsorb on the surface and interface of the reaction system, significantly changing the interface energy, but also enhance the repulsive force between the nanoparticles, preventing the nanoparticles from agglomerating, so that the prepared nanoparticles are evenly dispersed in the system.

[0032] In some embodiments, the solid content of the glycyrrhizic acid compound nanoparticle emulsion is 1-5 wt %.

[0033] Preferably, the solid content of the glycyrrhizic acid compound nanoparticle emulsion is 3 wt %.

[0034] The second method of the present invention provides a glycyrrhizic acid compound nanoparticle obtained according to the above-mentioned preparation method.

[0035] The third method of the present invention provides an application of the glycyrrhizic acid compound nanoparticles obtained according to the above-mentioned preparation method in the field of daily chemicals.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The present invention strictly controls the preparation process to prepare glycyrrhizic acid compounds and modified chitosan into nanoparticles with uniform particle size. The nanoparticles have good stability and antioxidant properties, can significantly reduce the effect of glycyrrhizic acid compounds on the viscosity of the carbomer system, and expand the application of glycyrrhizic acid compounds in the field of daily chemicals, especially in skin care products.

[0038] 2. In the present invention, epicatechin gallate is grafted onto the hydroxyl and amino groups on chitosan, with a high grafting rate, and the prepared modified chitosan has good ultraviolet protection and antioxidant capacity.

[0039] 3. In the present invention, a certain amount of Tween 80 is added to the reaction system of glycyrrhizic acid compound nanoparticles, which can significantly change the interfacial energy, enhance the repulsive force between nanoparticles, prevent the agglomeration of nanoparticles, and make the prepared nanoparticles evenly dispersed in the system, which is beneficial to improve the stability of skin care products. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] In order to better illustrate the specific implementation mode of the present invention, further examples are given below.

[0042] The initiator used in the present invention is ammonium persulfate; the glycyrrhizic acid compound used is dipotassium glycyrrhizinate; the carbomer used is Carbopol 910; and the chitosan used in the present invention is purchased from Shanghai Maokang Biotechnology Co., Ltd.

[0043] The chitosan used in Preparation Example 1-4 has a deacetylation degree of ≥95% and a Mw of 500,000.

[0044] Preparation Example 1

[0045] The preparation steps of modified chitosan are:

[0046] 1 g of chitosan and 1.5 g of epicatechin gallate were dissolved in 100 mL of 1 wt% acetic acid solution and stirred for 25 min to obtain a mixed solution. 0.11 g of ascorbic acid was added to the mixed solution. After nitrogen was introduced for 55 min, 0.3 g of initiator was added. The mixture was reacted at 25 ° C. in a nitrogen atmosphere for 22 h. Finally, it was dialyzed in deionized water for 70 h and freeze-dried to obtain modified chitosan.

[0047] Preparation Example 2

[0048] The preparation steps of the modified chitosan are the same as those in Preparation Example 1, except that 0.8 g of epicatechin gallate is used.

[0049] Preparation Example 3

[0050] The preparation steps of the modified chitosan are the same as those in Preparation Example 1, except that 0.8 g of ascorbic acid is used.

[0051] Preparation Example 4

[0052] The preparation steps of modified chitosan are:

[0053] 4 g of chitosan and 6 g of epicatechin gallate were dissolved in 100 mL of 1 wt% acetic acid solution and stirred for 25 min to obtain a mixed solution. 0.44 g of ascorbic acid was added to the mixed solution. After nitrogen was introduced for 55 min, 1 g of initiator was added. The mixture was reacted at 25 ° C. under a nitrogen atmosphere for 22 h. Finally, it was dialyzed in deionized water for 70 h and freeze-dried to obtain modified chitosan.

[0054] Preparation Example 5

[0055] The preparation steps of the modified chitosan are the same as those of Preparation Example 1, except that the chitosan used has a deacetylation degree of 71% and a Mw of 250,000.

[0056] Preparation Example 6

[0057] The preparation steps of the modified chitosan are the same as those of Preparation Example 1, except that the chitosan used has a deacetylation degree of ≥95% and a Mw of 800,000.

[0058] Example 1

[0059] A method for preparing glycyrrhizic acid compound nanoparticles comprises the following preparation steps:

[0060] (1) 5 g of modified chitosan was completely dissolved in 300 mL of 0.5 wt % acetic acid aqueous solution to prepare a modified chitosan aqueous solution;

[0061] (2) 0.75 g of a glycyrrhizic acid compound was completely dissolved in 225 mL of a 0.5 wt % aqueous ammonia solution to prepare a glycyrrhizic acid compound aqueous solution;

[0062] (3) at a rotation speed of 100 r / min, the modified chitosan aqueous solution obtained in step (1) and the glycyrrhizic acid compound aqueous solution obtained in step (2) were mixed to obtain a mixed solution, 5.25 g of Tween 80 was added thereto, and stirring was continued for 1 h to obtain a glycyrrhizic acid compound nanoparticle emulsion;

[0063] (4) freeze-drying the glycyrrhizic acid compound nanoparticle emulsion obtained in step (3) to obtain glycyrrhizic acid compound nanoparticles.

[0064] The modified chitosan used was obtained from Preparation Example 1.

[0065] Example 2

[0066] A method for preparing glycyrrhizic acid compound nanoparticles comprises the following preparation steps:

[0067] (1) 19 g of modified chitosan was completely dissolved in 300 mL of 1.5 wt % acetic acid aqueous solution to prepare a modified chitosan aqueous solution;

[0068] (2) 6.65 g of a glycyrrhizic acid compound was completely dissolved in 225 mL of a 1.5 wt % aqueous ammonia solution to prepare a glycyrrhizic acid compound aqueous solution;

[0069] (3) at a rotation speed of 100 r / min, the modified chitosan aqueous solution obtained in step (1) and the glycyrrhizic acid compound aqueous solution obtained in step (2) were mixed to obtain a mixed solution, 15.75 g of Tween 80 was added thereto, and stirring was continued for 3 h to obtain a glycyrrhizic acid compound nanoparticle emulsion;

[0070] (4) freeze-drying the glycyrrhizic acid compound nanoparticle emulsion obtained in step (3) to obtain glycyrrhizic acid compound nanoparticles.

[0071] The modified chitosan used was obtained from Preparation Example 1.

[0072] Example 3

[0073] A method for preparing glycyrrhizic acid compound nanoparticles comprises the following preparation steps:

[0074] (1) 12 g of modified chitosan was completely dissolved in 300 mL of 1 wt % acetic acid aqueous solution to prepare a modified chitosan aqueous solution;

[0075] (2) 3 g of a glycyrrhizic acid compound was completely dissolved in 225 mL of a 1 wt % aqueous ammonia solution to prepare a glycyrrhizic acid compound aqueous solution;

[0076] (3) at a rotation speed of 100 r / min, the modified chitosan aqueous solution obtained in step (1) and the glycyrrhizic acid compound aqueous solution obtained in step (2) were mixed to obtain a mixed solution, 10.5 g of Tween 80 was added thereto, and stirring was continued for 2 h to obtain a glycyrrhizic acid compound nanoparticle emulsion;

[0077] (4) freeze-drying the glycyrrhizic acid compound nanoparticle emulsion obtained in step (3) to obtain glycyrrhizic acid compound nanoparticles.

[0078] The modified chitosan used was obtained from Preparation Example 1.

[0079] Example 4

[0080] A method for preparing nanoparticles of glycyrrhizic acid compounds, the specific implementation method is the same as that of Example 3, except that the modified chitosan used is obtained from Preparation Example 2.

[0081] Example 5

[0082] A method for preparing glycyrrhizic acid compound nanoparticles, the specific implementation method is the same as that of Example 3, except that the modified chitosan used is obtained from Preparation Example 3.

[0083] Example 6

[0084] A method for preparing glycyrrhizic acid compound nanoparticles, the specific implementation method is the same as that of Example 3, except that the modified chitosan used is obtained from Preparation Example 4.

[0085] Example 7

[0086] A method for preparing glycyrrhizic acid compound nanoparticles, the specific implementation method is the same as that of Example 3, except that the modified chitosan used is obtained from Preparation Example 5.

[0087] Example 8

[0088] A method for preparing glycyrrhizic acid compound nanoparticles, the specific implementation method is the same as that of Example 3, except that the modified chitosan used is obtained from Preparation Example 6.

[0089] Example 9

[0090] A method for preparing glycyrrhizic acid compound nanoparticles, the specific implementation method is the same as that of Example 3, except that the glycyrrhizic acid compound used is 1.2 g.

[0091] Example 10

[0092] A method for preparing glycyrrhizic acid compound nanoparticles, the specific implementation method is the same as that of Example 3, except that 9 g of Tween 80 is used.

[0093] Comparative Example 1

[0094] A method for preparing nanoparticles of glycyrrhizic acid compounds, the specific implementation method is the same as that of Example 3, except that an equal mass of unmodified chitosan is used instead of modified chitosan.

[0095] Comparative Example 2

[0096] A method for preparing glycyrrhizic acid compound nanoparticles, the specific implementation method is the same as that of Example 3, except that an equal mass of sodium dodecyl sulfate is used instead of Tween 80.

[0097] Performance Testing

[0098] 1. Determination of the grafting rate (total phenol content) of the modified chitosan obtained in the preparation example: weigh 10 mg of the modified chitosan and dissolve it in 100 mL of 1 wt% acetic acid solution, take 1 mL of it and mix it with 1 mL of 10-fold diluted Folin phenol reagent, react for 5 minutes, then add 5 mL of saturated sodium carbonate solution, stir evenly, and let it stand in a dark environment for 2 hours to react, measure the absorbance of the solution at 760 nm, and substitute it into the standard curve to calculate the grafting rate.

[0099] Standard curve: first dissolve epicatechin gallate in deionized water to prepare 0 mg / mL, 0.2 mg / mL, 0.5 mg / mL, 0.7 mg / mL, 1 mg / mL, 1.5 mg / mL, 2 mg / mL, and 3 mg / mL standard solutions, take 1 mL of it and mix it with 1 mL of 10-fold diluted folin phenol reagent, react for 5 minutes, then add 5 mL of saturated sodium carbonate solution, stir evenly, let it react in a dark environment for 2 hours, and measure the absorbance of the solution at 760 nm to make a standard curve.

[0100] The specific test results are shown in Table 1.

[0101] Table 1

[0102]

[0103] As shown in Table 1, the grafting rate of the modified chitosan obtained in Preparation Example 1 is the highest, while in Preparation Examples 2-6, the grafting rate of epicatechin gallate on chitosan is affected due to the changes in the preparation conditions (the amount of epicatechin gallate, the amount of ascorbic acid, the concentration of chitosan, the deacetylation degree of chitosan, and the molecular weight of chitosan).

[0104] The following performance tests were performed on the glycyrrhizic acid compound nanoparticles obtained in the examples and comparative examples:

[0105] 2. Effect of glycyrrhizic acid compound nanoparticles on the viscosity of carbomer solution: 0.5 g of the glycyrrhizic acid compound nanoparticles obtained in the embodiment and the comparative example were respectively added to 98 mL of 0.5 wt% carbomer aqueous solution, stirred evenly, and allowed to stand for 2 h. The viscosity was tested using the “T / FDCA 004-2020 Determination of Cosmetic Viscosity - Rotational Rheometer Method”, and the 0.5 wt% carbomer aqueous solution was used as a blank control group.

[0106] 3. Antioxidant capacity (DPPH radical scavenging activity) of glycyrrhizic acid compound nanoparticles: The glycyrrhizic acid compound nanoparticles obtained in the examples and comparative examples were prepared into standard solutions with concentrations of 0 mg / mL, 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL, and 0.5 mg / mL, and 1 mL and 3 mL of 0.04 mg / mL DPPH-methanol solution were taken respectively to react for 30 min under dark conditions, centrifuged at 5000 r / min for 10 min, and then the absorbance of the solution was measured at 517 nm. A mixture of 1 mL of deionized water and 3 mL of 0.04 mg / mL DPPH-methanol solution was used as a blank control; then dipotassium glycyrrhizinate and modified chitosan were prepared into standard solutions with concentrations of 0 mg / mL, 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL, and 0.5 mg / mL, and tested in the same manner as above;

[0107] DPPH free radical scavenging activity (%) = 100% × (A0-A1) / A0, wherein A0 is the absorbance of the blank control group, and A1 is the absorbance of the glycyrrhizic acid compound nanoparticle solution.

[0108] The specific test results are shown in Table 2.

[0109] Table 2

[0110] serial number Solution viscosity (Pa·S) Antioxidant capacity (%) Blank control group 22 5 Example 1 21 80 Example 2 22 83 Example 3 22 85 Example 4 16 76 Example 5 17 72 Example 6 16 70 Example 7 14 65 Example 8 15 68 Example 9 17 71 Example 10 18 69 Comparative Example 1 17 72 Comparative Example 2 14 76 Dipotassium glycyrrhizinate solution -- 44 Modified chitosan solution -- 13

[0111] As shown in Table 2, although both the dipotassium glycyrrhizinate solution and the modified chitosan solution have certain antioxidant properties, their antioxidant properties are relatively weak when used alone. The antioxidant properties of the glycyrrhizic acid compound nanoparticles prepared in Examples 1-3 are significantly higher than those of the dipotassium glycyrrhizinate solution and the modified chitosan solution, and the glycyrrhizic acid compound nanoparticles have little effect on the viscosity of the carbomer solution.

[0112] Compared with Example 3, the glycyrrhizic acid compound nanoparticles prepared in Examples 4-8 changed the preparation process conditions, which affected the grafting rate of epicatechin gallate on chitosan, thereby affecting the comprehensive properties of the modified chitosan, so that the antioxidant capacity of the prepared glycyrrhizic acid compound nanoparticles was weakened to varying degrees, and the viscosity of the carbomer solution was significantly reduced.

[0113] Compared with Example 3, Example 9 changes the dosage of glycyrrhizic acid compound, resulting in decreased difficulty in synthesis, stability and comprehensive performance of glycyrrhizic acid compound nanoparticles; Example 10 changes the dosage of Tween 80, making the prepared glycyrrhizic acid compound nanoparticles prone to agglomeration and decreased comprehensive performance, thereby weakening the antioxidant capacity of the prepared glycyrrhizic acid compound nanoparticles to varying degrees, and significantly reducing the viscosity of the carbomer solution.

[0114] Compared with Example 3, in Comparative Example 1, unmodified chitosan is used instead of modified chitosan. Although glycyrrhizic acid compound nanoparticles can be synthesized, their antioxidant performance is poor and the viscosity of the carbomer solution is greatly affected; in Comparative Example 2, sodium dodecyl sulfate is used instead of Tween 80. The dispersion effect of sodium dodecyl sulfate on glycyrrhizic acid compound nanoparticles in the system is weaker than that of Tween 80. The reason may be that sodium dodecyl sulfate is not an anionic surfactant, which causes the glycyrrhizic acid compound nanoparticles to agglomerate, reduce the comprehensive performance, and significantly reduce the antioxidant ability and the viscosity of the carbomer solution.

[0115] The above is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present application. Although the present application is disclosed as above in the preferred embodiment, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution.

Claims

1. A method for preparing glycyrrhizic acid compound nanoparticles, characterized in that: The method comprises the following preparation steps: (1) completely dissolving the modified chitosan in a 0.5-1.5 wt % acidic aqueous solution to prepare a modified chitosan aqueous solution; (2) completely dissolving the glycyrrhizic acid compound in a 0.5-1.5 wt % alkaline aqueous solution to prepare a glycyrrhizic acid compound aqueous solution; (3) under stirring, mixing the modified chitosan aqueous solution obtained in step (1) and the glycyrrhizic acid compound aqueous solution obtained in step (2) to obtain a mixed solution, adding Tween 80 thereto, and continuing stirring for 1-3 hours to obtain a glycyrrhizic acid compound nanoparticle emulsion; (4) freeze-drying the glycyrrhizic acid compound nanoparticle emulsion obtained in step (3) to obtain glycyrrhizic acid compound nanoparticles; The preparation steps of the modified chitosan are: Dissolve chitosan and epicatechin gallate in an acetic acid solution, stir for 20-30 minutes to obtain a mixed solution, add ascorbic acid to the mixed solution, pass an inert gas for 50-60 minutes, add an initiator, react at 20-25° C. and in an inert gas atmosphere for 20-24 hours, finally dialyze in deionized water for 65-75 hours, and freeze-dry to obtain modified chitosan; The mass ratio of chitosan, epicatechin gallate and ascorbic acid is 1:(1-2):(0.1-0.12); The chitosan has a deacetylation degree of ≥90% and a Mw of 200,000-500,000; The glycyrrhizic acid compound in the mixed solution is 15-35wt% of the modified chitosan; The amount of Tween 80 added is 1-3wt% of the mixed solution; The initiator is one or more of ammonium persulfate, potassium persulfate and hydrogen peroxide; The glycyrrhizic acid compounds are glycyrrhizic acid and glycyrrhizic acid salt; The mass concentration of the chitosan in the acetic acid solution is 0.5-3%.

2. The method for preparing glycyrrhizic acid compound nanoparticles according to claim 1, characterized in that: The solid content of the glycyrrhizic acid compound nanoparticle emulsion is 1-5wt%.

3. A glycyrrhizic acid compound nanoparticle prepared according to the method for preparing glycyrrhizic acid compound nanoparticles according to claim 1 or 2.

4. Application of glycyrrhizic acid compound nanoparticles prepared by the method for preparing glycyrrhizic acid compound nanoparticles according to claim 1 or 2 in the field of daily chemicals.

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