Stable composition containing epigallocatechin gallate and preparation method and application thereof

Abstract

The invention discloses a stable composition containing epigallocatechin gallate as well as a preparation method and application of the stable composition. The stable composition is prepared from glycerol, vitamin C, chlorogenic acid, ethyoxyl diethylene glycol and epigallocatechin gallate. The preparation method comprises the following steps: mixing glycerol and epigallocatechin gallate at room temperature, stirring and dispersing uniformly, heating to 75-80 DEG C, and stirring until complete dissolution to obtain a transparent solution which is a phase A; uniformly stirring vitamin C, chlorogenic acid and ethyoxyl diethylene glycol at room temperature to obtain a transparent solution which is a phase B; and uniformly mixing the phase A and the phase B to obtain the stable composition. The composition has the characteristics of high temperature resistance, illumination resistance and high stability, and the preparation method of the composition is simple and low in cost.

Description

Technical Field

[0001] The invention relates to a composition containing epigallocatechin gallate, in particular to a stable composition containing epigallocatechin gallate and a preparation method and application thereof. Background Art

[0002] Epigallocatechin gallate (EGCG) is one of the catechins, with the highest content, which can reach 50%. The structural characteristics of catechins are that there are two or three phenolic hydroxyl groups on the B-ring and 5,7-diphenolic hydroxyl groups on the A-ring, so they have antioxidant activity. In addition to the phenolic hydroxyl groups on the above two rings, EGCG also has three phenolic hydroxyl groups on the D-ring (structural formula 1). Among the four main catechins, it has the strongest antioxidant activity. EGCG has good water solubility, and its antioxidant activity is more than 100 times that of vitamin C and 25 times that of vitamin E. In skin care products, it has the effects of anti-oxidation and moisturizing, removing yellowness and brightening, anti-inflammatory and soothing, anti-pollution, and anti-aging, and is an active ingredient that is deeply recognized by consumers.

[0003] However, the special structure of EGCG is extremely unstable, especially in water, where it is prone to self-oxidation, hydrolysis, polymerization, isomerization and other reactions, making it difficult to use stably in cosmetics. Attempts have been made to add EGCG to cosmetics by adjusting the pH, adding chelating agents and antioxidants, but it is difficult to maintain stability during the shelf life, and obvious discoloration, taste change, and inactivation still occur. In addition, some raw material suppliers will perform molecular modification on EGCG, insert glucoside, palmitoyl, or introduce other molecules for encapsulation, in an attempt to solve the stability problem of EGCG application, but the results are not good, and the stability is still not ideal; moreover, the modification process of molecular modification is complicated, resulting in a substantial increase in the price of raw materials, high cost, and low cost performance.

[0004] In the prior art, an apple polyphenol deodorizing mouthwash and its preparation method with application number 202110118899.7 discloses "the composition by mass percentage is: chlorogenic acid 0.05%-0.08%, catechin 0.07%-0.1%, phlorizin 0.1%-0.2%, anthocyanin 0.06%-0.08%, xylitol 1%-3%, potassium sorbate 0.1%-0.2%, vitamin C 0.02%-0.04%, salt 0.1%-0.3%, ethanol 5%-8%, glycerol 8%-10%, deionized water is added to 100% to prepare apple polyphenol deodorizing mouthwash."

[0005] However, the mouthwash in the above patent is a water-containing formula, in which the catechins are easily oxidized and inactivated, and have poor light and heat stability. Summary of the invention

[0006] The purpose of the present invention is to provide a stable composition containing epigallocatechin gallate and its preparation method and application. The composition of the present invention has the characteristics of high temperature resistance and light resistance, high stability, simple preparation method and low cost.

[0007] The technical solution of the present invention is a stable composition containing epigallocatechin gallate, which is composed of glycerol, vitamin C, chlorogenic acid, ethoxydiglycol and epigallocatechin gallate.

[0008] The aforementioned stable composition containing epigallocatechin gallate is composed of the following components in parts by weight: 80 to 100 parts of glycerol, 0.1 to 0.5 parts of vitamin C, 0.001 to 0.04 parts of chlorogenic acid, 1 to 13 parts of ethoxydiglycol and 0.01 to 30 parts of EGCG.

[0009] The aforementioned stable composition containing epigallocatechin gallate is composed of the following components in parts by weight: 84.15 parts of glycerol, 0.33 parts of vitamin C, 0.02 parts of chlorogenic acid, 13 parts of ethoxydiglycol and 2.5 parts of EGCG.

[0010] The aforementioned stable composition containing epigallocatechin gallate is composed of the following components in parts by weight: 76.65 parts of glycerol, 0.33 parts of vitamin C, 0.02 parts of chlorogenic acid, 13 parts of ethoxydiglycol and 10 parts of EGCG.

[0011] The method for preparing the above-mentioned stable composition comprises the following steps:

[0012] A. Mix glycerol and epigallocatechin gallate at room temperature, stir and disperse evenly, heat to 75-80°C, stir until completely dissolved to obtain a transparent solution, which is phase A;

[0013] B. Stir vitamin C, chlorogenic acid and ethoxydiglycol at room temperature to obtain a transparent solution, which is phase B;

[0014] C. Mix phase A and phase B evenly to obtain a stable composition.

[0015] The above-mentioned stable composition can be used in cosmetics.

[0016] A cosmetic is in the form of two compartments, one of which stores a stable composition containing epigallocatechin gallate, and the other stores a water-containing composition. The method for using the cosmetic is to mix the compositions in the two compartments while using the cosmetic.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The composition of the present invention adopts four specific common cosmetic ingredients, namely glycerin, vitamin C, chlorogenic acid and ethoxydiglycol, and the ingredients are safe and reliable; and the ingredients are combined in a reasonable ratio to fuse substances with different solubilities together to form a stable and uniform solution.

[0019] Among them, VC, as a super antioxidant, preferentially sacrifices itself to consume the oxygen or free radicals in the system, protects EGCG from oxidation, reduces the pH of the system, and maintains the pH of the system stable under various test conditions, inhibits the hydrolysis and oxidation of EGCG, and prompts chlorogenic acid to provide powerful antioxidant and chelating effects in the later stage, stabilizing the EGCG solution.

[0020] The composition can stabilize EGCG of different concentrations under different storage conditions, especially high-concentration EGCG with a concentration of up to 10%. Even under the conditions of 45°C + light and 50°C, it can still ensure stability for a long time. It has good water solubility and can be better divided into warehouses and applied to cosmetics, ensuring that the appearance and content changes are low during the shelf life, and the effects of anti-oxidation and moisturizing, yellowing and brightening, anti-inflammatory and soothing, anti-pollution, and anti-aging are effectively exerted.

[0021] The preparation method of the invention is simple, the ingredients are common, and compared with the prior art, it has the advantages of high efficiency and high cost performance.

[0022] Therefore, the composition of the present invention has the characteristics of high temperature resistance and light resistance and high stability, and the preparation method of the composition is simple and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a diagram of the initial dissolution state of EGCG in Comparative Examples 1-9 of the present invention.

[0024] Figure 2 It is a graph showing the stability results of Comparative Examples 1-9 of the present invention after one month under different conditions.

[0025] Figure 3 It is a graph showing the stability results of Comparative Examples 1-9 of the present invention after 3 months under different conditions.

[0026] Figure 4 It is a statistical graph of the EGCG retention rate of comparative examples 1-9 of the present invention after storage for 3 months under 45° C. light conditions.

[0027] Figure 5 It is a graph showing the stability results of comparative examples 10-17 of the present invention under different conditions for one month.

[0028] Figure 6 It is a graph showing the stability results of Example 1, Comparative Example 1, Comparative Example 8, and Comparative Examples 18-19 of the present invention under different conditions for one month.

[0029] Figure 7 It is a graph showing the stability results of Example 1, Comparative Example 1, Comparative Example 8, and Comparative Examples 18-19 of the present invention under different conditions for 3 months.

[0030] Figure 8 It is a statistical graph of EGCG retention rates after storage under different conditions in Example 1, Comparative Example 1, Comparative Example 8, and Comparative Examples 18-19 of the present invention.

[0031] Fig. 9 It is a graph showing the stability results of Example 1 of the present invention and Comparative Example 20 after being stored for one month under different conditions.

[0032] Fig.10 1 is a graph showing the stability results of Example 1, Comparative Example 18, Comparative Example 19 and Comparative Example 21 of the present invention after being stored under different conditions for one month.

[0033] Fig.11 It is a statistical graph of the IC50 of DPPH free radical scavenging rate of Example 1, Comparative Example 18, Comparative Example 19 and Comparative Example 21 of the present invention after being stored under different conditions for one month.

[0034] Fig.12 This is a graph showing the stability results of Examples 1-4 after storage for 1 month under different conditions. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the embodiments, but they are not intended to limit the present invention.

[0036] Embodiment 1:

[0037] The invention discloses a stable composition containing epigallocatechin gallate, which is composed of the following raw materials in percentage by weight: 84.15% of glycerol, 13% of ethoxydiglycol, 0.33% of vitamin C, 0.02% of chlorogenic acid and 2.5% of epigallocatechin gallate.

[0038] The preparation method of the above embodiment comprises the following steps:

[0039] A. Mix glycerol and epigallocatechin gallate at room temperature, stir and disperse evenly, heat to 75-80°C, stir until completely dissolved to obtain a transparent solution, and cool to room temperature to obtain phase A;

[0040] B. Stir vitamin C, chlorogenic acid and ethoxydiglycol at room temperature to obtain a transparent solution, which is phase B;

[0041] C. Mix phase A and phase B evenly to obtain a stable composition.

[0042] The above composition can be used in cosmetics. The cosmetics contain ingredients in the form of two compartments, one of which stores a stable composition containing epigallocatechin gallate, and the other stores a water-containing composition. The method of using the cosmetics is to mix the two compartment compositions while using.

[0043] The formulations of different embodiments and comparative examples are shown in Table 1:

[0044] Table 1. Formulations of various embodiments and comparative examples

[0045]

[0046]

[0047] Comparative Examples 1-9 were respectively recorded as AI, and the solubility of the AI ​​group and the stability under different conditions for 1 month and 3 months were measured. The stability test conditions were: room temperature, -15°C, 45°C, 45°C light, and 45°C light for 3 months. The test conditions were: 45°C light for 1 month + room temperature for 2 months. The solubility test results are shown in Table 2, and the stability test results are shown in Table 3. Figure 1-3 .in Figure 1 is the initial state diagram of each group, Figure 2 The degree of discoloration after one month under different conditions. Figure 3 The color change degree after 3 months under different conditions.

[0048] Table 2. Dissolution state of EGCG

[0049]

[0050] As can be seen from Table 2, the solubility of EGCG in most polyols is not particularly good, and it needs to be heated to 80°C in a water bath for a certain period of time before it can be dissolved. However, it can be dissolved in 1,3-propylene glycol and ethoxydiglycol by stirring at room temperature.

[0051] from Figure 1-3It can be seen that at room temperature and -15°C, ECGG does not change color in the corresponding solvents. However, at -15°C, EGCG will precipitate from water, and its low-temperature solubility is poor, indicating that EGCG has a certain fat solubility. Under the conditions of 45°C heat resistance and 45°C light, the EGCG solution has a certain discoloration phenomenon, especially the 45°C light is more serious. Under the condition of 45°C heat resistance for 1 month, the pure glycerol system has the slightest discoloration and the best performance, followed by the glycerol system containing 10% and 20% alcohol, and the discoloration is relatively small. The discoloration of other solvent systems is relatively obvious, especially the water, ethoxydiglycol and 1,3-propylene glycol systems, which have very serious discoloration. Under the condition of 45℃ illumination for 1 month, the discoloration is aggravated. Under the condition of 45℃ heat resistance for 3 months, the discoloration degree of each group of compositions is further aggravated than that under the condition of 45℃ illumination for 1 month. Under the condition of 45℃ illumination for 1 month + room temperature for 2 months, the discoloration degree of each system is further aggravated than that under the condition of 45℃ for 3 months. Among them, the pure glycerol system is the most stable and the dipropylene glycol system is the least stable.

[0052] The retention rate of EGCG after AI was stored at 45°C for 3 months under light conditions was calculated using the HPLC standard curve method. Retention rate = (EGCG remaining content / EGCG initial content) * 100%. The initial sample content of EGCG was 2.5% wt (pure product 2.39% wt). The test results are shown in Tables 3 and Figure 4 shown.

[0053] Table 3. EGCG content after storage for 3 months under 45℃ light conditions

[0054]

[0055] From Table 3 and Figure 4 It can be seen that the retention rate of EGCG in the pure glycerol system is the highest, with a retention rate of 95.40%; the retention rate of ethoxydiglycol system is the lowest, with a retention rate of 62.76%.

[0056] The pH value of the AI ​​group was tested under different storage conditions, and the test results are shown in Table 4.

[0057] Table 4. pH values ​​of EGCG solutions in each group after storage for 3 months

[0058]

[0059]

[0060] Note: 45℃ light test conditions are: 1 month at 45℃ light + 2 months at room temperature

[0061] From the pH values ​​in Table 4, it can be seen that at 45°C and 45°C illumination, the pH of the system decreases, and the decrease is greater at 45°C illumination. The pure glycerol system has the smallest pH change among all systems. Combined with the above test results, it can be seen that the darker the color of the system, the lower the pH, and high temperature and light accelerate the hydrolysis and oxidation reactions of EGCG. Therefore, using glycerol as a solvent can, on the one hand, reduce the presence of water and oxygen in the system and reduce various consumption reactions; on the other hand, it can stabilize the acid-base environment of the system and inhibit the occurrence of related reactions.

[0062] Although it can be seen from the above experiments that glycerol is the most ideal solvent for protecting EGCG, most antioxidants cannot be directly dissolved in glycerol. Therefore, ethoxydiglycol was introduced as a medium solvent to dissolve the antioxidants.

[0063] The stability of Comparative Examples 10 to Comparative Examples 17 was tested for 1 month under different conditions such as 25°C, -15°C, 45°C, and 45°C light. The test results are shown in Figure 5 .from Figure 5 It can be seen that comparative example 11 has the best stability. Compared with the system without antioxidants, the comparative examples 11 and 12 containing VC have less discoloration and better stability under heat and light conditions for 1 month, especially the stability under light conditions has been greatly improved, and ethoxydiglycol has a better stability effect on EGCG than water. The above experiments show that ethoxydiglycol alone and antioxidants including chlorogenic acid, ferulic acid and lipoic acid will accelerate the discoloration of EGCG solution, while VC can enhance the stability of the EGCG glycerol system and offset the negative effects of ethoxydiglycol.

[0064] The stability of Example 1, Comparative Example 1, Comparative Example 8, Comparative Examples 18-19 was tested for 1 month and 3 months at room temperature, -15°C, 45°C, 45°C light, 50°C, etc., and the retention rate of EGCG was calculated by HPLC standard curve method. The retention rate of EGCG % = (EGCG residual content / EGCG initial content) * 100%, and the initial content of EGCG was 2.39wt%. The results of the 1-month stability test are shown in Figure 6 , 3-month stability results are shown in Figure 7 The 3-month test conditions are 45℃ and -15℃ for 3 months, and the remaining test conditions are corresponding conditions for 1 month + room temperature for 2 months.

[0065] Table 5. EGCG retention rate (%) of EGCG solution after storage under different conditions

[0066]

[0067] from Figure 6-7It can be seen that Example 1 has the best stability and the lowest degree of color change, while Comparative Examples 8 and 19 have very serious color changes due to the presence of water. From the previous experiments, it can be seen that ethoxydiglycol and chlorogenic acid have a negative impact on the stability of the system when used alone. Combined with Example 1 and Comparative Example 18, it can be seen that glycerol has a good protective effect on EGCG, and when VC and chlorogenic acid are used in combination, they can not only eliminate the negative effects of chlorogenic acid on the system when used alone, but also promote the chlorogenic acid to play a role in stabilizing EGCG.

[0068] The retention rates of EGCG in Example 1, Comparative Example 1, Comparative Example 8, and Comparative Examples 18-19 are shown in Tables 5 and Figure 8 . It can be seen that, except for the water-containing comparative examples 8 and 19 which will precipitate at -15°C, the stability of the other groups is the best at -15°C, and the EGCG retention rate of Example 1 is the highest under all conditions, which has a great effect on improving the stability of high temperature + light. The addition of chlorogenic acid has a more obvious effect on improving the stability of the system under long-term high temperature and light. However, the stability of the aqueous EGCG system is poor, and the EGCG retention rate is low.

[0069] The stability of Example 1 and Comparative Example 20 was tested for 1 month at room temperature, -15°C, 45°C, 45°C light, and 50°C, and the retention rate of EGCG was calculated using the HPLC standard curve method. The stability test results are shown in Fig. 9 ,The test results of retention rate are shown in Table 5.

[0070] from Fig. 9 It can be seen that after each group of samples completed the 1-month test, Example 1 basically did not change color, while Comparative Example 20 changed color significantly, especially under 45°C light conditions. This shows that when the antioxidants in the EGCG system are the same, the solvent glycerol can protect the color of the system, and as all glycerol is replaced by ethoxydiglycol, the heat resistance and light resistance stability of the system deteriorate. It can also be seen from Table 5 that under 45°C light conditions, the retention rate of EGCG in Example 1 is 95.40%, while the retention rate in Comparative Example 20 is only 80.75%, which proves that the glycerol in the composition protects the system better than ethoxydiglycol.

[0071] The stability and scavenging rate of DPPH free radicals were tested after the accelerated storage of Example 1, Comparative Example 18, Comparative Example 19 and Comparative Example 21 at room temperature, -15°C, 45°C + light, and 50°C for 1 month. The test results are shown in Table 1. Fig.10 , Fig.11 As shown in Table 7. Among them, the sample at -15°C needs to be dissolved by slight heat before testing the scavenging rate of DPPH free radicals.

[0072] Table 6. DPPH free radical scavenging rate IC50 after EGCG solution was stored for 1 month

[0073]

[0074]

[0075] From the experimental results, it can be seen that after one month of accelerated experiment, Example 1 has the best color change stability, the lowest IC50 value under heat and light, and the strongest free radical scavenging ability. Moreover, the same antioxidant has a lower effect in water than in glycerol. In the water system, the free radical scavenging ability of chlorogenic acid combined with VC is weaker than that of VC alone, indicating that in the water system, chlorogenic acid and VC have side effects.

[0076] The stability test of Examples 1-4 was conducted for one month at -15°C, 45°C light, and 50°C. The test results are shown in Fig.12 .from Fig.12 It can be seen that the embodiments containing different EGCG concentrations have good stability under different storage conditions and are not prone to discoloration.

[0077] Based on the above data, it is shown that the composition of VC, chlorogenic acid, ethoxydiglycol and glycerol of the present invention has a good protective effect on EGCG and can maintain long-term stability under high temperature and light conditions.

Claims

1. A stable composition containing epigallocatechin gallate, characterized in that: It is composed of glycerin, vitamin C, chlorogenic acid, ethoxydiglycol and epigallocatechin gallate.

2. The stable composition containing epigallocatechin gallate according to claim 1, characterized in that: The following components in parts by weight Composition: 80-100 parts of glycerin, 0.1-0.5 parts of vitamin C, 0.001-0.04 parts of chlorogenic acid, 1-13 parts of ethoxydiglycol and 0.01-30 parts of EGCG.

3. The stable composition containing epigallocatechin gallate according to claim 1, characterized in that: The invention is composed of the following ingredients in parts by weight: 84.15 parts of glycerin, 0.33 parts of vitamin C, 0.02 parts of chlorogenic acid, 13 parts of ethoxydiglycol and 2.5 parts of EGCG.

4. The stable composition containing epigallocatechin gallate according to claim 1, characterized in that: The invention is composed of the following ingredients in parts by weight: 76.65 parts of glycerin, 0.33 parts of vitamin C, 0.02 parts of chlorogenic acid, 13 parts of ethoxydiglycol and 10 parts of EGCG.

5. The method for preparing the stable composition according to any one of claims 1 to 4, characterized in that: The following steps are involved: A. Mix glycerol and epigallocatechin gallate at room temperature, stir and disperse evenly, heat to 75-80°C, stir until completely dissolved to obtain a transparent solution, which is phase A; B. Stir vitamin C, chlorogenic acid and ethoxydiglycol at room temperature to obtain a transparent solution, which is phase B; C. Mix phase A and phase B evenly to obtain a stable composition.

6. Use of the stable composition according to any one of claims 1 to 4 in cosmetics.

7. A cosmetic comprising the stable composition according to any one of claims 1 to 4, characterized in that: The cosmetic is in the form of two compartments, one of which stores a stable composition containing epigallocatechin gallate, and the other stores a water-containing composition. The method for using the cosmetic is to mix the compositions of the two compartments while using the cosmetic.

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