A microemulsion containing plant polyphenols, and a preparation method and application thereof

Abstract

The application discloses a microemulsion containing plant polyphenols and a preparation method and application thereof. The microemulsion comprises plant polyphenols, a main emulsifier, a co-emulsifier, oil and water. The co-emulsifier is combined by a sulfur-containing compound and a polyhydric alcohol, wherein the sulfur-containing compound comprises one or more of thioctic acid, cystine and cysteine. The application provides a preparation method of the microemulsion containing plant polyphenols for cosmetics and medicines. The application can greatly improve the solubility, stability, antioxidant property and transdermal efficiency of the plant polyphenol active substance, and improves the bioavailability of the plant polyphenol active substance in the field of cosmetics and medicines.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of micro-nano carriers, and particularly relates to a microemulsion containing plant polyphenols and a preparation method and application thereof. BACKGROUND

[0002] Plant polyphenols, also known as plant tannins, are secondary metabolites with antioxidant, anti-inflammatory and antibacterial activities, and widely exist in the bark, roots, leaves and fruits of plants, and can reduce the oxidative damage of lipids, proteins, enzymes, carbohydrates and DNA in living cells and tissues, and thus can be used as a natural antioxidant in different fields.

[0003] Exposure of the skin to the environment, such as smoke, microorganisms or ultraviolet radiation, can cause biological reactions, including hyperplasia, erythema, photoaging and skin cancer, and especially UVA radiation can penetrate the dermal tissue and affect the skin components. After irradiation of skin fibroblasts, it can cause the activity of catalase and superoxide dismutase to decrease. At present, the beneficial effects of plant polyphenols as functional ingredients have attracted widespread attention in the medical and cosmetic industries, and many skin care products based on plant polyphenol-rich extracts have been developed.

[0004] Although more and more plant polyphenols are applied to the fields of cosmetics and medicine, further research is still needed in the solubility and skin penetration of polyphenols. In order to exert biological activity, the substances applied topically must be able to be released from the formula, reach the skin, and finally overcome the barrier of the stratum corneum, penetrate the epidermis, and further transdermal release of active substances mainly depends on the molecular properties, such as molecular weight and lipophilicity.

[0005] Plant polyphenols have various pharmacological activities such as anti-inflammatory and antioxidant activities, but many plant polyphenols have poor water solubility and low stability, and are easily degraded under natural light and high temperature, resulting in very low bioavailability. SUMMARY

[0006] This section is intended to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification of the present application in order to avoid obscuring the purpose of this section, the abstract and the title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0007] In view of the above and / or problems existing in the prior art, the present application is proposed.

[0008] Therefore, the purpose of the present application is to overcome the deficiencies in the prior art, and to provide a microemulsion containing plant polyphenols.

[0009] To solve the above technical problems, the present application provides the following technical scheme: a microemulsion containing plant polyphenols, comprising,

[0010] plant polyphenol, primary emulsifier, co-emulsifier, oil and water;

[0011] The co-emulsifier is a combination of sulfur-containing compound and polyhydric alcohol, the plant polyphenol is 0.1-5% by mass percentage of total raw materials, the primary emulsifier is 10-15%, the co-emulsifier is 5-10%, the oil is 1-5%, and the balance is water to make up to 100%.

[0012] As a preferred scheme of the microemulsion containing plant polyphenol of the present application, the sulfur-containing compound includes one or more of thioctic acid, cystine and cysteine.

[0013] As a preferred scheme of the microemulsion containing plant polyphenol of the present application, the polyhydric alcohol includes one or more of glycerol, ethanol, propylene glycol, butylene glycol and pentylene glycol.

[0014] As a preferred scheme of the microemulsion containing plant polyphenol of the present application, the mass ratio of the polyhydric alcohol to the sulfur-containing compound is 1:1-1:2.

[0015] As a preferred scheme of the microemulsion containing plant polyphenol of the present application, the plant polyphenol includes one or more of grape polyphenol, apple polyphenol, soybean isoflavone, silymarin, resveratrol, quercetin and curcumin.

[0016] As a preferred scheme of the microemulsion containing plant polyphenol of the present application, the primary emulsifier includes one or more of PEG-40 hydrogenated castor oil, PEG-60 hydrogenated castor oil, PEG-8 caprylic capric glyceride, polyglyceryl-10 laurate and PEG-20 phytosterol.

[0017] As a preferred scheme of the microemulsion containing plant polyphenol of the present application, the oil includes one or more of caprylic capric triglyceride, isopropyl myristate, octyldodecanol, squalane and hydrogenated polydecene.

[0018] Another object of the present application is to overcome the deficiencies in the prior art and provide a preparation method of a microemulsion containing plant polyphenol, comprising,

[0019] Mixing the primary emulsifier, the polyhydric alcohol and the sulfur-containing compound to obtain an emulsifier;

[0020] Mixing the emulsifier, the oil and water uniformly to obtain a transparent, thermodynamically stable microemulsion;

[0021] Slowly adding the plant polyphenol into the microemulsion under stirring to obtain a microemulsion containing plant polyphenol.

[0022] As a preferred scheme of the preparation method of the microemulsion containing plant polyphenols, according to the total mass percentage of raw materials, the plant polyphenols are 0.1-5%, the main emulsifier is 10-15%, the co-emulsifier is 5-10%, the oil is 1-5%, and the balance is water to make up to 100%, wherein the co-emulsifier is a combination of sulfur-containing compounds and polyols, and the mass ratio of polyols to sulfur-containing compounds is 1:1-1:2.

[0023] Another object of the present application is to overcome the deficiencies in the prior art and provide an application of the microemulsion containing plant polyphenols in the preparation of cosmetics and drugs.

[0024] The present application has the following beneficial effects:

[0025] (1) The microemulsion containing plant polyphenols prepared by the present application has good solubilizing capacity for plant polyphenols, which can increase the solubility of plant polyphenols in the oil phase by nearly 50 times, and the addition of plant polyphenols has no obvious effect on the particle size and stability of the microemulsion, and the microemulsion system significantly improves the light stability, thermal stability and storage stability of plant polyphenols.

[0026] (2) The microemulsion loaded with plant polyphenols in the present application shows enhanced transdermal performance, and the skin accumulation amount of the microemulsion is 6-8 times higher than that of the curcumin emulsifier oil solution without water, and the prepared microemulsion can significantly improve the antioxidant property of plant polyphenols; the microemulsion containing plant polyphenols prepared by the present application can be applied in cosmetics and drugs. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0028] Figure 1 The microemulsion phase diagram of sample 2 in Example 1 of the present application.

[0029] Figure 2 (A) UV spectrum and (B) particle size distribution diagram of curcumin encapsulated by the microemulsion in the present application, wherein (a) is the initial macroscopic photograph of the curcumin microemulsion, and (b) is the macroscopic photograph after 30 days of storage in a dark room at 25°C.

[0030] Figure 3 The effect of light time and temperature on the stability of curcumin in the present application, wherein ethanol is curcumin-ethanol solution.

[0031] Figure 4Figure for inhibition rate of TBARS after microemulsion loaded curcumin in the embodiment of the present application.

[0032] Figure 5 Figure for comparison of SOD and GSH content in cells after UVA irradiation of different treated cells in the embodiment of the present application.

[0033] Figure 6 Figure for comparison of curcumin content in different layers of skin after the sample in the embodiment of the present application is applied to pig skin. DETAILED DESCRIPTION

[0034] In order to make the above objectives, features and advantages of the present application more apparent, the specific embodiments of the present application will be described in detail below with reference to the embodiments of the present application.

[0035] In the following description, a lot of specific details are set forth in order to facilitate a full understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0036] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0037] Embodiment 1

[0038] The sample was prepared according to the raw material ratio in Table 1.

[0039] The main emulsifier, polyol and sulfur-containing compound were mixed according to the proportion in the table to obtain an emulsifier, and the emulsifier, oil and water were mixed according to the proportion in the table to prepare a microemulsion;

[0040] The plant polyphenol was slowly added to the microemulsion under stirring to obtain a microemulsion containing plant polyphenol.

[0041] Table 1

[0042]

[0043]

[0044] Embodiment 2

[0045] Active substance solubility test:

[0046] Curcumin is a natural active ingredient with various pharmacological activities such as anti-inflammatory and antioxidant effects. However, it has poor water solubility and low stability, and is easily degraded under natural light and high temperatures, resulting in very low bioavailability. Using microemulsions as an encapsulation system can effectively improve these problems.

[0047] Test method: The solubility of curcumin was studied by ultraviolet-visible spectroscopy. The maximum absorption wavelength of curcumin was 425 nm.

[0048] Sample: Saturated aqueous solution of curcumin in sample 1 (weigh excess curcumin and disperse it in 20 mL of water, sonicate for 30 min, let stand for 12 h, and obtain the supernatant by centrifugation);

[0049] Sample 2: Saturated octyldodecyl alcohol solution of curcumin (Weigh out excess curcumin and disperse it in 20 mL of octyldodecyl alcohol, sonicate for 30 min, let stand for 12 h, and then obtain the supernatant by centrifugation);

[0050] Sample 3: Saturated microemulsion of curcumin (curcumin was added to Sample 2 in Example 1 until the microemulsion was about to break or curcumin solids precipitated out, and then the supernatant was obtained by centrifugation).

[0051] Table 2 Solubility of curcumin in each component

[0052] Type of component Water Octyldodecanol Microemulsion Curcumin solubility (mg / L) 0.1876 151.0836 7564.7627

[0053] The results in the table above show that the microemulsion prepared by this invention can increase the solubility of curcumin by more than 50 times compared with that in the oil phase, indicating that the microemulsion system exhibits good solubilizing properties for curcumin.

[0054] Example 3

[0055] Comparison of the stability of active ingredients

[0056] To evaluate the stability protection effect of the microemulsion system of the present invention as a carrier on plant polyphenols, the storage stability, light and heat stability of curcumin in the microemulsion system of sample 2 in Example 1 were investigated.

[0057] The storage stability of curcumin microemulsion was assessed by storing it in a 25°C water bath away from light. The results are as follows: Figure 2 As shown.

[0058] The microemulsion encapsulating curcumin retained 79.56% of its volume after 90 days of storage, without exhibiting turbidity or stratification. Figure 2 (B Insert Figure). This indicates that curcumin was not released from the microemulsion, therefore the microemulsion system of this invention has a certain stabilizing effect on curcumin.

[0059] The sample 2 in Example 1 was irradiated under a natural incandescent lamp, and the retention rate of curcumin was determined at different times using ultraviolet-visible spectroscopy, compared with a curcumin-ethanol solution, and the results are shown in Figure 3 As shown in A. After irradiation for 20 h under the same light conditions, the retention rate of curcumin in the microemulsion (>95%) was higher than that in ethanol (<78%), indicating that the use of the microemulsion of the present application to encapsulate curcumin can significantly improve its light stability.

[0060] After sample 2 was placed at different temperatures for 3 h, the retention rate of curcumin was as shown in Figure 3 B. At different temperatures, the retention rate of curcumin encapsulated in the microemulsion decreased slowly, and at 75°C, the retention rate of curcumin in the microemulsion was still greater than 96%, while the retention rate of curcumin in ethanol had decreased to below 80%, indicating that the use of the present application to encapsulate curcumin can significantly improve its thermal stability.

[0061] Example 4

[0062] DPPH· radical scavenging capacity

[0063] The antioxidant properties of the microemulsion of the present application were studied using 1,1-diphenyl-2-trinitrobenzene hydrazine radical (DPPH·) as a model molecule.

[0064] Test method: The microemulsion sample and 0.1 mmol / L DPPH· ethanol solution were mixed at a volume ratio of 1:1, the system was placed in the dark for 30 min, and the absorbance at 517 nm (AS) was measured. A blank group (curcumin microemulsion-ethanol system) was prepared according to the above procedure, and its absorbance at 517 nm (A O ) was measured. The DPPH· radical scavenging rate was calculated by the following formula:

[0065] DPPH· radical scavenging rate = (A s -A0) / A0

[0066] Sample: Sample 2 in Example 1

[0067] Control group 1: Sample 2 in Example 1 (lipoic acid in the formula is replaced with a polyol, no lipoic acid is added)

[0068] Control group 2: Sample 2 in Example 1 (curcumin in the formula is replaced with lipoic acid, no curcumin is added, the total amount of lipoic acid added is 4.3%)

[0069] Table 3 Solubility of curcumin in each component

[0070] Type of component Sample 2 Control 1 Control 2 DPPH· radical scavenging rate (%) 93.97 65.09 1.49

[0071] From Table 3, it can be seen that the preferred microemulsion of the present application can significantly improve the scavenging effect of curcumin on DPPH· free radicals, which is much higher than the highest value of 85.75% reported in the literature. Through the control group experiment, it can be found that this excellent DPPH· free radical scavenging effect is not a simple addition of curcumin and sulfur-containing compounds, but a synergistic effect on the interface of microemulsion nanodroplets.

[0072] Example 5

[0073] Anti-lipid peroxidation ability

[0074] Test method: The anti-lipid peroxidation ability was investigated by using the thiobarbituric acid (TBARS) method.

[0075] The anti-lipid peroxidation ability of curcumin ethanol solution with a concentration range of 0.05-0.30 mg / mL and sample 2 was determined.

[0076] The inhibition rates of curcumin ethanol solution and curcumin microemulsion of the present application on TBARS are shown in Table 4. Figure 4 The ability of both to inhibit the generation of TBARS is enhanced with the increase of their concentrations, showing good anti-lipid peroxidation ability. However, the TBARS inhibition rate of the curcumin microemulsion of the present application is significantly better than that of curcumin ethanol solution at the same concentration.

[0077] Example 6

[0078] SOD and GSH are important antioxidant enzymes in cells, and their activities are closely related to the content of intracellular ROS. External stimuli such as UVA and H2O2 can reduce the activity of SOD and the content of GSH, leading to a significant increase in the content of intracellular ROS and causing obvious oxidative damage to cells.

[0079] Test method: HSF cells in the logarithmic growth phase were inoculated in a transparent 6-well plate, 2 mL per well, so that the cell density was 4×10 5 4 / mL per well, and cultured in a 37℃, 5% CO2, and humidity-saturated incubator for 24 h. The DMEM was removed, and the sample diluted with DMEM was added, 2 mL per well, so that the concentration of curcumin was 150 μg / mL, and the incubation was continued in the incubator for 24 h. The DMEM was removed, 1 mL of PBS was added, and UVA irradiation was performed in an ultraviolet crosslinking instrument for 40 min. After PBS washing, the SOD and GSH reagent kits were used for treatment, and the activity of intracellular SOD and the content of GSH were determined.

[0080] Sample: sample 2 in Example 1

[0081] Control group 1: sample 2 in Example 1 (thioctic acid in the formula is replaced with polyol, and no thioctic acid is added)

[0082] Control group 2: sample 2 in example 1 (replace curcumin in the formula with lipoic acid, no curcumin added, total amount of lipoic acid added is 4.3%)

[0083] Control group 3: DMSO solution of curcumin (dissolve curcumin in DMSO to make its mass fraction 0.3%)

[0084] After UVA irradiation, the activity of SOD and the content of GSH in the cells are significantly reduced, while the cells treated with the curcumin microemulsion can significantly inhibit the reduction of SOD activity and GSH content, protect the cells from oxidative damage, and are significantly better than the protection of free curcumin and blank microemulsion on the cells.

[0085] Lipoic acid in the blank microemulsion can also inhibit the reduction of SOD activity and GSH content, and protect the cells from oxidative damage. When curcumin is added to the microemulsion, lipoic acid and curcumin can achieve a synergistic effect, greatly improving the effect of inhibiting the reduction of SOD activity and GSH content, and significantly improving the antioxidant performance.

[0086] Example 7

[0087] Transdermal test

[0088] Test method: The in vitro transdermal absorption performance of the curcumin microemulsion sample was studied by Franz diffusion cell.

[0089] Sample: sample 2 in example 1

[0090] Control group 1: sample 2 in example 1 (replace water in the formula with octyldodecanol)

[0091] From Figure 6 It can be seen that curcumin microemulsion and control group 1 have no detection of curcumin in the receiving liquid, indicating that curcumin will not penetrate the skin to reach the subcutaneous tissue and participate in blood circulation, laying a foundation for its application in cosmetics; in addition, compared with control group 1, curcumin in curcumin microemulsion can better penetrate the epidermis to reach the dermis, effectively promoting the transdermal absorption of curcumin, and the total transdermal content is increased from (1.75 ± 0.18) μg / cm 2 to (9.24 ± 0.27) μg / cm 2 . Overall, the curcumin-loaded microemulsion shows enhanced transdermal performance, with a 5.3-fold increase in skin accumulation compared to control group 1 without water, indicating that the curcumin microemulsion prepared by the present application is a promising curcumin transdermal drug carrier.

[0092] Example 8

[0093] Human efficacy test

[0094] The skin brightness L* value of the typical position of the face of the subject is measured. The higher the L* value, the brighter the skin color; the higher the L* value growth rate, the better the skin brightness improvement effect. The samples are prepared by using the emulsion formulations in Table 4. The subjects use emulsion 1 and emulsion 2 on the left and right sides of the face respectively, and the skin brightness L* value is measured after 28 days. After using blank emulsion 2, the skin brightness of the subject increases by 0.71%; after using emulsion 1 for 28 days, the skin brightness increases by 4.42%, which is obviously better than the blank emulsion.

[0095] Table 4 Emulsion formulation

[0096]

[0097]

[0098] Although more and more plant polyphenols are applied to the fields of cosmetics and medicine, further research is still needed in the solubility and skin penetration of polyphenols. In order to exert biological activity, the substances applied topically must be able to be released from the formula, reach the skin, and finally overcome the barrier of the stratum corneum, penetrate into the epidermis, and further transdermal release of active substances mainly depends on the molecular properties such as molecular weight and lipophilicity.

[0099] Plant polyphenols have various pharmacological activities such as anti-inflammatory and antioxidant activities, but many plant polyphenols have poor water solubility, low stability, and are easily degraded under natural light and high temperature, resulting in very low bioavailability. The use of microemulsion as a loading system can effectively improve the above problems. The microemulsion system not only can be used as a carrier for encapsulating plant polyphenols to increase their solubility, but also can improve their stability and antioxidant activity, which is of great significance for further expanding the application range of plant polyphenols.

[0100] In view of the problems of poor stability, low solubility and poor skin permeability of plant polyphenols, the microemulsion prepared by combining sulfur compounds with emulsifiers can greatly improve the solubility of plant polyphenol active substances, and can increase the solubility of plant polyphenols in the oil phase by 50 times. The addition of active substances has no significant effect on the particle size and stability of the microemulsion, and the microemulsion system improves the light stability, thermal stability and storage stability of plant polyphenol active substances. The presence of the compound further improves the antioxidant activity of the microemulsion system, and the average value of DPPH·RSA reaches 91.74%, which is higher than the reported value. In addition, the microemulsion loaded with active substances shows enhanced transdermal performance, and the skin accumulation of the active substance emulsifier oil solution is about 4 times higher.

[0101] The microemulsion containing plant polyphenols prepared by the present application has application prospects in the fields of cosmetics and medicine due to its unique structure and functional properties.

[0102] It should be noted that the above examples are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced, without departing from the spirit and scope of the technical solutions of the present application, which should be covered in the scope of the claims of the present application.

Claims

1. A microemulsion containing plant polyphenols, characterized by: The application relates to a microemulsion containing plant polyphenols. The plant polyphenols, the main emulsifier, the auxiliary emulsifier, the oil and water; The auxiliary emulsifier is a combination of a sulfur-containing compound and a polyhydric alcohol, the plant polyphenols are 0.1-5% of the total mass of raw materials, the main emulsifier is 10-15%, the auxiliary emulsifier is 5-10%, the oil is 1-5%, and the rest is water to make up to 100%; The mass ratio of the polyhydric alcohol to the sulfur-containing compound in the auxiliary emulsifier is 1:1-1:2; The sulfur-containing compound is thioctic acid; The polyhydric alcohol is one or more of glycerol, ethanol, propylene glycol, butanediol and pentanediol; The plant polyphenols are curcumin; The main emulsifier is one or more of PEG-40 hydrogenated castor oil, PEG-60 hydrogenated castor oil, PEG-8 caprylic acid capric acid glyceride and polyglyceryl-10 laurate.

2. The microemulsion containing plant polyphenols according to claim 1, characterized in that: The oil includes one or more of caprylic acid capric acid triglyceride, isopropyl myristate, octyldodecanol, squalane and hydrogenated polydecene.

3. The method for preparing the microemulsion containing plant polyphenols according to claim 1 or 2, characterized by: The application relates to a microemulsion containing plant polyphenols. The main emulsifier, the polyhydric alcohol and the sulfur-containing compound are mixed to obtain an emulsifier; The emulsifier, the oil and water are uniformly mixed to obtain a transparent, thermodynamically stable microemulsion; The plant polyphenols are slowly added into the microemulsion under stirring to obtain a microemulsion containing plant polyphenols.

4. The application of the microemulsion containing plant polyphenols in cosmetics and medicines according to claim 1 or 2.

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