Antibacterial and acne-removing microemulsion containing plant extract and preparation method thereof

Abstract

The application discloses a bacteriostatic and acne-removing microemulsion containing plant extracts and a preparation method thereof. The bacteriostatic and acne-removing microemulsion contains a microemulsion loaded with quercetin alone, a microemulsion loaded with sasanquasapernin alone, and a microemulsion loaded with quercetin and sasanquasapernin simultaneously. The bacteriostatic and acne-removing microemulsion containing plant extracts prepared by the application not only solves the problems of stickiness of camellia oil and poor solubility of quercetin, but also has a synergistic inhibitory effect on propionibacterium acnes, achieves the same high-efficiency bacteriostatic effect with a lower drug concentration, saves drug cost, reduces drug irritation, and expands the application of quercetin and sasanquasapernin in the cosmetic and pharmaceutical fields due to the rich pharmacological effect of the plant extracts, low side effect and safety. The microemulsion system prepared by the application is clear, transparent, uniform and stable, the preparation process is simple, the required energy is low, the cost is low, and the system is beneficial to commercial production.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical formulation technology, specifically to an antibacterial and acne-reducing microemulsion containing plant extracts and its preparation method, and more specifically to an antibacterial and acne-reducing microemulsion containing quercetin and / or camellia saponin and its preparation method. Background Technology

[0002] Acne is a chronic inflammatory skin disease of the hair follicles and sebaceous glands, and it is self-limiting. It commonly appears on the face, back, and chest of adolescents and adults, manifesting as comedones, papules, pustules, nodules, and cysts. The main clinical manifestation is the ability to squeeze out a white, rice-grain-like powdery substance. After treatment, 3%–7% of acne patients will experience scarring, negatively impacting their physical and mental health. Propionibacterium acnes is the main microorganism causing acne and driving the inflammatory response; therefore, inhibiting its growth is currently the primary approach to acne treatment. While antibiotics are known to inhibit microbial growth, long-term use can lead to severe drug resistance in pathogens and may even harm the skin and the body. Compared to antibiotics, plant extracts offer advantages such as rich pharmacological effects, low side effects, and safety with multiple benefits, making the exploration of novel anti-P. acnes drugs of great significance.

[0003] Quercetin, a natural plant extract, possesses a variety of biological activities. Belonging to the flavonoid family, it exhibits antioxidant and free radical scavenging effects, as well as anticancer, anti-inflammatory, antibacterial, and cardiovascular protective pharmacological activities. It can inhibit the production of bacterial extracellular polysaccharide matrix, thereby reducing the formation of extracellular polysaccharide-protein complexes. Furthermore, by disrupting the integrity of biological membranes, it makes it easier for antibacterial drugs to act on bacteria, thus inhibiting bacterial growth. Quercetin has few side effects and no teratogenic, carcinogenic, or mutagenic toxicity, making it widely used in clinical practice. However, quercetin is almost insoluble in water (<0.5 μg / g) and oil (<1 mg / g), has poor oral absorption, low bioavailability, and is easily degraded, which greatly limits its development and application in the pharmaceutical field.

[0004] Camellia oleifera Abel. is one of the world's four major woody oil crops. Camellia oil is rich in nutrients and high in unsaturated fatty acids, earning it the reputation of "Oriental olive oil." With increasing demand for healthy diets, the camellia oil industry has flourished. my country produces approximately 2.65 million tons of camellia seeds annually, with about 700,000 tons of camellia seed meal remaining after oil processing. The saponins in this meal are mainly camellia saponins. Currently, camellia saponins are primarily used for sterilization in animal and aquatic product processing areas or are simply discarded, failing to be fully utilized. However, camellia saponins are a natural and excellent surfactant with strong foaming, emulsifying, dispersing, and wetting properties. They are low-cost and have good inhibitory effects on bacteria and fungi, with the antibacterial effect positively correlated with saponin concentration. Furthermore, they possess anti-inflammatory, analgesic, and anticancer physiological activities.

[0005] Microemulsions are typically stable, transparent or translucent liquid dispersions composed of appropriate proportions of oil, water, surfactants, and co-surfactants. They are isotropic and thermodynamically stable. Microemulsions have particle sizes in the 10-100 nm range and extremely low surface tension. When used as carriers for transdermal drug delivery, microemulsions offer advantages such as increased drug solubility, nanoscale particle size, the ability of components to act as penetration enhancers, low surface tension, and high thermodynamic stability. These advantages facilitate the penetration of hydrophilic, lipophilic, and amphiphilic drugs through the stratum corneum and increase drug retention in the skin. Since the pore diameter of human skin is only 60 nm, active ingredients such as quercetin and camellia oil saponins can also penetrate deep into the dermis through these pores with the aid of microemulsion technology, maximizing their bioactivity.

[0006] Su Qiaoling et al. studied the antibacterial properties of tea saponin extracted from tea lees in the Sanjiang area of ​​Guangxi. The antibacterial test showed that the tea saponin solution had a significant inhibitory effect on Staphylococcus epidermidis, but the required concentration of tea saponin solution was high, and the inhibitory effect was closely related to the concentration. Only when the concentration of tea saponin reached 60 mg / mL could there be a significant inhibitory effect on Staphylococcus epidermidis. The antibacterial effect of the tea saponin obtained by this process was not obvious, the required concentration was too high, which increased the cost, and it may also cause certain skin irritation, so it could not be applied to the cosmetics and pharmaceutical fields (Su Qiaoling, Ye Youming, Zhu Tiantian. Process optimization and antibacterial study of tea saponin extracted from tea lees [J]. Feed Research, 2022, 45(13): 83-87.). Wang Yumei et al. found that the MIC of Paris saponins I, II, and IV against Propionibacterium acnes was 125 μg / mL. The results showed that Paris saponins I, II, and IV had a relatively significant antibacterial effect against Propionibacterium acnes. However, saponins must be extracted from traditional Chinese medicine, and the separation and extraction process is complicated, with problems such as long extraction time and insufficient extraction. Therefore, the cost is very high and cannot be promoted and applied on a large scale (Wang Yumei, Fan Qian, Liu Bairu, Hu Jinshan, Zhang Cuixian. Study on the in vitro antibacterial effect of different saponin components of Paris on acne-related pathogens [J]. Chinese Journal of Integrated Traditional and Western Medicine Dermatology and Venereology, 2022, 21(03):225-227.).

[0007] In recent years, scholars both domestically and internationally have explored the effects of quercetin on skin inflammation associated with acne. Lim HJ et al. investigated the effects of quercetin on inflammatory skin diseases induced by Propionibacterium acnes. When Propionibacterium acnes was injected intradermally into the ears of mice, it caused skin erythema and swelling. After treatment with quercetin, the thickness and swelling of the ears were significantly reduced. These results indicate that Propionibacterium acnes can be used to treat skin inflammation caused by Propionibacterium acnes. However, this study increased the solubility of quercetin by using DMSO. DMSO is restricted by the US Food and Drug Administration to use in non-special and non-irreplaceable situations. DMSO has a small molecular weight and is easily absorbed by the skin. Long-term skin contact with DMSO can cause some local irritation reactions, such as itching and burning sensation, thus limiting its wide application in pharmaceuticals and cosmetics (Lim HJ, Kang SH, Song YJ, et al. Inhibitory Effect of Quercetin on Propionibacterium acnes-induced Skin Inflammation[J]. International Immunopharmacology, 2021, 96:107557.). Li Anping et al. disclosed a new bioactivity and use of a natural flavonoid compound—its application as an antibacterial agent in inhibiting human pathogens (patent CN113368102A). The study investigated the antibacterial activity of quercetin against Escherichia coli and Staphylococcus aureus. The results showed that when the concentration of quercetin was 0.8 mg / mL, the inhibition rates against both bacteria were 66.37% and 63.09%, respectively, indicating a weak antibacterial effect. Furthermore, the study did not investigate the inhibitory effect of quercetin on Propionibacterium acnes.

[0008] Chinese patent CN110063925A discloses an acne-removing composition and its preparation method, which includes 0.05-50 parts of quercetin, and in addition to quercetin, also contains ethanol, glycerin, naringenin, chlorogenic acid, eucalyptus oil, eugenol, emodin, menthyl lactate, tea polyphenols, American cockroach extract, allantoin, and vitamin A acetate. Although this composition has good antibacterial effects, its complex and numerous components result in high costs and may cause skin irritation. Furthermore, the lack of added water prevents it from carrying sufficient amounts of water-soluble drugs, limiting its application in cosmetics or pharmaceutical preparations. When applied to the skin, it may cause severe greasiness and even clog pores, hindering its large-scale application.

[0009] Quercetin is a poorly soluble drug, almost insoluble in water (<0.5 μg / g) and oil (<1 mg / g), with low bioavailability and easy degradation. It is necessary to find a suitable carrier to solubilize it in order to fully exert its biological activity.

[0010] Although the above studies have demonstrated the antibacterial properties of quercetin and tea oil saponins, they have not explored the combined pharmacological effects of the two. Moreover, there are still a series of problems, such as the lack of obvious antibacterial effect, the high required drug concentration, the high cost, the heavy oily feeling, and the inability of the solvent to be applied to the skin, which greatly limit their application in the fields of cosmetics and medicine. Summary of the Invention

[0011] In order to solve the above-mentioned technical problems, the purpose of this invention is to provide an antibacterial and acne-removing microemulsion containing plant extracts (quercetin and / or tea oil saponin) and its preparation method.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0013] An antibacterial and acne-reducing microemulsion containing plant extracts, the antibacterial and acne-reducing microemulsion comprising: a microemulsion loaded with quercetin alone, a microemulsion loaded with camellia saponin alone, and a microemulsion loaded with both quercetin and camellia saponin.

[0014] The raw materials for microemulsions loaded with quercetin alone include: camellia oil, deionized water, co-surfactant, surfactant, and quercetin.

[0015] The raw materials for microemulsions carrying camellia saponin alone include: camellia oil, deionized water, co-surfactant, surfactant, and camellia saponin.

[0016] The raw materials for the microemulsion loaded with quercetin and camellia saponin include: camellia oil, deionized water, co-surfactant, surfactant, quercetin, and camellia saponin.

[0017] The co-surfactant is at least one of ethanol and 1,2-propanediol; the surfactant is Tween 85.

[0018] The preparation method of the above-mentioned antibacterial and acne-removing microemulsion containing plant extracts includes the following steps:

[0019] (1) Camellia oil is thoroughly mixed with Tween 85 and co-surfactant to obtain mixture A, wherein the mass fraction of camellia oil is 10%-50%, the mass fraction of Tween 85 is 40%-72%, and the mass fraction of co-surfactant is 10%-18%.

[0020] (2) Mix mixture A thoroughly with quercetin to obtain mixture B;

[0021] (3) Dissolve camellia saponin in deionized water to obtain camellia saponin aqueous solution;

[0022] (4) Under stirring conditions, add the aqueous solution of tea oil saponin or deionized water dropwise to mixture B or mixture A until it becomes a clear and transparent microemulsion system.

[0023] Furthermore, in step (2), the mass fraction of quercetin in mixture B is 0-1.7%.

[0024] Furthermore, in step (3), the mass fraction of the camellia saponin aqueous solution is 0-12.5%.

[0025] Furthermore, in step (4), the obtained microemulsion system is ultrasonically treated and then centrifuged to maintain its clarity, transparency, and stable properties.

[0026] Furthermore, in step (4), the microemulsions obtained include microemulsions loaded with quercetin alone, microemulsions loaded with camellia saponin alone, and microemulsions loaded with both quercetin and camellia saponin, all of which belong to the oil-in-water system.

[0027] Furthermore, in step (4), the microemulsions individually loaded with quercetin and microemulsions individually loaded with camellia saponin can be continuously diluted twice with nutrient broth.

[0028] The microemulsions containing quercetin prepared in this invention exhibit an inhibition rate of ≥99.873% against Propionibacterium acnes when the quercetin concentration is ≥0.875 mg / mL.

[0029] The microemulsion containing camellia saponin prepared by this invention exhibits an inhibition rate of ≥96.754% against Propionibacterium acnes when the concentration of camellia saponin is ≥25 mg / mL.

[0030] In the microemulsion simultaneously loaded with quercetin and camellia saponin prepared by this invention, the concentration of quercetin required to inhibit Propionibacterium acnes to more than 90% was reduced to 0.109 mg / mL, and the concentration of camellia saponin was reduced to 0.781 mg / mL.

[0031] This invention loads quercetin and camellia oleifera saponin into a microemulsion. When used as a carrier for transdermal drug delivery, the microemulsion promotes drug penetration through the stratum corneum, thus solving the technical problem of quercetin's poor solubility. Compared to quercetin aqueous solution (0.1% DMSO) and camellia oleifera saponin solution, the microemulsion, when loaded with either quercetin or camellia oleifera saponin alone, shows a significant inhibitory effect on the growth of Propionibacterium acnes, especially within the first 24 hours, where the number of Propionibacterium acnes decreases most rapidly. Therefore, this microemulsion system facilitates the action of plant extracts quercetin and camellia oleifera saponin on Propionibacterium acnes and inhibits its growth. When the microemulsion is used in combination with quercetin and camellia oleifera saponin, it has a synergistic inhibitory effect on Propionibacterium acnes, greatly reducing the required drug concentration to achieve the desired antibacterial effect. The same antibacterial effect is achieved with a lower drug concentration, maximizing the combined efficacy of quercetin and camellia oleifera saponin. This not only saves on drug costs but also reduces drug irritation, making it suitable for acne treatment. Furthermore, the plant extracts offer a wealth of pharmacological effects, low side effects, and are safe and multi-functional, expanding the application of quercetin and camellia oil saponins in cosmetics and pharmaceuticals.

[0032] Compared with the prior art, the present invention has the following beneficial effects and advantages:

[0033] (1) The antibacterial and acne-removing microemulsion containing plant extracts prepared in this invention improves the solubility of quercetin, increases its antibacterial pharmacological activity, can be applied to transdermal drug delivery, improves the bioavailability of quercetin, and expands the application of quercetin in the pharmaceutical field.

[0034] (2) The preparation method of the present invention improves the hydrophobic properties of camellia oil, forming an oil-in-water microemulsion with a clear and transparent appearance, which is easier to absorb through the skin, has good dispersibility, and better stability. The resulting microemulsion system can be infinitely diluted with water, expanding its application in water-based cosmetics.

[0035] (3) The antibacterial and acne-removing microemulsion containing plant extracts prepared in this invention is loaded with both the poorly soluble substance quercetin and the water-soluble substance camellia saponin. This not only solves the problems of the stickiness of camellia oil and the poor solubility of quercetin, but also the quercetin and camellia saponin contained therein have a synergistic inhibitory effect on Propionibacterium acnes. The prepared drug-loaded microemulsion has a synergistic inhibitory effect on Propionibacterium acnes. A high antibacterial rate can be achieved with a lower drug concentration, saving drug costs. Moreover, it is suitable for local administration and can be applied to acne treatment, avoiding the problem of poor absorption when taken orally.

[0036] (4) The preparation process of the present invention is simple, requires low energy, does not require high temperature treatment, has low cost, is suitable for industrial production, and does not pollute the environment. Attached Figure Description

[0037] Figure 1The diagram shows the inhibitory effect of the camellia oil microemulsion loaded with quercetin prepared in Example 1 on Propionibacterium acnes.

[0038] Figure 2 The diagram shows the inhibitory effect of the camellia oil microemulsion loaded with camellia saponin prepared in Example 2 on Propionibacterium acnes.

[0039] Figure 3 The time-inhibition curves of camellia oil microemulsion loaded with quercetin and quercetin aqueous solution (0.1% DMSO) prepared in Example 1 are shown.

[0040] Figure 4 The time-antibacterial curves of the camellia oil microemulsion and the camellia saponin aqueous solution loaded with camellia saponin prepared in Example 2 are shown. Detailed Implementation

[0041] The specific implementation of the present invention will be further described below with reference to specific embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0042] Example 1

[0043] A method for preparing a quercetin-containing antibacterial and acne-reducing microemulsion includes the following steps:

[0044] (1) Camellia oil, Tween 85 and ethanol are thoroughly mixed and stirred for 20 min at a speed of 500 r / min to obtain mixture A, in which the mass fraction of camellia oil is 50%, the mass fraction of Tween 85 is 40% and the mass fraction of ethanol is 10%.

[0045] (2) Mixture A with quercetin thoroughly for 90 minutes, at a speed of 500 r / min, and at a temperature of 25°C to obtain mixture B. The mass fraction of quercetin in mixture B is 1.7%.

[0046] (3) Prepare 20 mL of deionized water.

[0047] (4) Under stirring conditions, deionized water is added dropwise to mixture B until it becomes a clear and transparent microemulsion system. It is then treated with ultrasonic waves at 20 kHz for 30 min and water bath at 25 ℃ for 12 h. It can be infinitely diluted with water.

[0048] Example 2

[0049] A method for preparing an antibacterial and acne-reducing microemulsion containing camellia saponin includes the following steps:

[0050] (1) Camellia oil, Tween 85 and ethanol are thoroughly mixed. The stirring time is 20 min, the speed is 500 r / min and the temperature is 25℃ to obtain mixture A, in which the mass fraction of camellia oil is 23.81%, the mass fraction of Tween 85 is 53.33% and the mass fraction of ethanol is 13.33%.

[0051] (2) Dissolve camellia saponin in deionized water, stirring for 5 minutes at a speed of 500 r / min to obtain an aqueous solution of camellia saponin. The mass fraction of the aqueous solution of camellia saponin is 12.5%.

[0052] (3) Under stirring conditions, add the camellia saponin aqueous solution dropwise to mixture A until it becomes a clear and transparent microemulsion system. Treat with 20kHz ultrasound for 30min and water bath at 25℃ for 12h. It can be infinitely diluted with water.

[0053] Example 3

[0054] A method for preparing an antibacterial and acne-removing microemulsion containing quercetin and camellia oil saponin includes the following steps:

[0055] (1) Camellia oil, Tween 85 and ethanol are thoroughly mixed. The stirring time is 20 min, the speed is 500 r / min and the temperature is 25℃ to obtain mixture A, in which the mass fraction of camellia oil is 10%, the mass fraction of Tween 85 is 60.95% and the mass fraction of co-surfactant is 15.24%.

[0056] (2) Mixture A with quercetin thoroughly for 90 minutes, at a speed of 500 r / min, and at a temperature of 25°C to obtain mixture B. The mass fraction of quercetin in mixture B is 1.11%.

[0057] (3) Dissolve camellia saponin in deionized water, stirring for 5 minutes at a speed of 500 r / min to obtain an aqueous solution of camellia saponin. The mass fraction of the aqueous solution of camellia saponin is 3.33%.

[0058] (4) Under stirring conditions, add the camellia saponin aqueous solution dropwise to mixture B until it becomes a clear and transparent microemulsion system. Treat with 20kHz ultrasound for 30 minutes and water bath at 25℃ for 12 hours. It can be infinitely diluted with water.

[0059] Performance testing

[0060] 1. Stability study of the microemulsions prepared in Examples 1, 2, and 3

[0061] The microemulsions prepared in Examples 1, 2, and 3 were diluted with water and their centrifugal stability was investigated, including the following steps: Appropriate amounts of the microemulsions prepared in each example were taken and centrifuged at 6000 r / min, 8000 r / min, and 10000 r / min for 20 min, and the separation was observed. The results showed that the microemulsions still exhibited strong stability after centrifugation at different speeds, remained clear and transparent without separation, showed good drug solubility, and showed no precipitation. The PDI was less than 0.3, indicating that the microemulsions were well dispersed in the continuous phase with fewer opportunities for aggregation and better stability.

[0062] 2. Identification of Microemulsion Types Prepared in Examples 1, 2, and 3

[0063] The type of microemulsion prepared was determined by staining. The results showed that the diffusion rate of water-soluble methylene blue in the microemulsions of Examples 1, 2, and 3 was higher than that of oil-soluble dye Sudan Red, indicating that the microemulsions obtained in Examples 1, 2, and 3 were all oil-in-water type.

[0064] 3. Synergistic inhibitory effect of the microemulsions prepared in Examples 1 and 2 on Propionibacterium acnes

[0065] The camellia oil microemulsion loaded with quercetin prepared in Example 1 was continuously diluted twice with nutrient broth, and then diluted with an equal volume of 10 6 The bacterial suspensions were mixed at CFU / mL to achieve final quercetin concentrations of 3.5 mg / mL, 1.7505 mg / mL, 0.8755 mg / mL, 0.4385 mg / mL, and 0.2195 mg / mL. After mixing, the mixtures were anaerobically cultured at 37°C for 48 hours. A blank control group, a growth control group, and a solvent control group were also set up. Each concentration was tested in triplicate, and the OD600 value was measured. The minimum inhibitory concentration of the microemulsion for this bacterial strain was defined as 90% inhibition rate.

[0066] The camellia oil microemulsion loaded with camellia saponin prepared in Example 2 was continuously diluted twice with nutrient broth, and then diluted with an equal volume of 10 6 The bacterial suspensions were mixed at CFU / mL to achieve final concentrations of 50 mg / mL, 25 mg / mL, 12.5 mg / mL, 6.25 mg / mL, 3.125 mg / mL, and 1.563 mg / mL of camellia saponin. After mixing, the mixtures were anaerobically cultured at 37°C for 48 hours. A blank control group, a growth control group, and a solvent control group were also set up. Each concentration was replicated in triplicate, and the OD600 value was measured. The minimum inhibitory concentration of the microemulsion for this bacterial strain was defined as 90% inhibition rate.

[0067] The microemulsions prepared in Examples 1 and 2, along with quercetin aqueous solution (0.1% DMSO) and camellia saponin aqueous solution, were added to the nutrient broth. Propionibacterium acnes bacteria in the logarithmic growth phase were then inoculated into the broth and cultured to a final bacterial concentration of 10. 6 The concentrations of quercetin and camellia oleifera saponins were adjusted to a final concentration of 0.875 mg / mL using CFU / mL. The dynamic growth of *Propionibacterium acnes* was observed in quercetin microemulsion, camellia oleifera saponin microemulsion, quercetin aqueous solution (0.1% DMSO), and camellia oleifera saponin aqueous solution. The control group (without any drugs) was used. After 6, 12, 24, 36, and 48 hours of culture, the solutions were diluted to specific concentrations and plated on agar plates. After anaerobic incubation at 37°C for 48 hours, the concentrations (CFU / mL) were counted.

[0068] The microemulsions prepared in Examples 1 and 2 were serially diluted twice with nutrient broth. Quercetin was diluted to eight concentration gradients, ranging from 7 mg / mL to 0.055 mg / mL; camellia oil saponin was diluted to seven concentration gradients, ranging from 100 mg / mL to 1.563 mg / mL. Following a checkerboard pattern (as shown in Table 1), 50 μL of camellia oil microemulsion loaded with quercetin, 50 μL of camellia oil microemulsion loaded with camellia oil saponin, and 100 μL of 10... 6 CFU / mL bacterial suspension. After mixing, it was anaerobically cultured at 37℃ for 48 h. A blank control group, a growth control group, and a solvent control group were set up. Each concentration was performed in triplicate. The OD600 value was measured. The minimum inhibitory concentration of the drug in the well for the bacterial strain was defined as 90% inhibition rate.

[0069] Table 1

[0070]

[0071]

[0072] The results showed that, Figure 1 and Figure 2 When the microemulsion was loaded with quercetin alone, the inhibition rate against *Propionibacterium acnes* was ≥99.873% when the quercetin concentration was ≥0.875 mg / mL, meaning the minimum inhibitory concentration (MIC) of quercetin against *Propionibacterium acnes* was 0.875 mg / mL. When the microemulsion was loaded with camellia oleifera saponin alone, the inhibition rate against *Propionibacterium acnes* was ≥96.754% when the camellia oleifera saponin concentration was ≥25 mg / mL, meaning the MIC of camellia oleifera saponin against *Propionibacterium acnes* was 25 mg / mL.

[0073] Depend on Figure 3 and Figure 4It is known that when the microemulsion is loaded with quercetin and tea oil saponin alone, and the concentrations are 0.875 mg / mL and 25 mg / mL, respectively, the growth of Propionibacterium acnes in the logarithmic growth phase is significantly inhibited. Moreover, in the first 24 hours of action, the microemulsion loaded with the drug alone has a more significant inhibitory effect than the corresponding aqueous solution, and the number of Propionibacterium acnes decreases faster. Therefore, the microemulsion system of the present invention is more conducive to the drug exerting its antibacterial effect. The reason is likely that the nanostructure of the microemulsion is more conducive to the plant extract entering and destroying the cell structure of Propionibacterium acnes.

[0074] Table 2

[0075]

[0076] As shown in Table 2, when quercetin and camellia saponin are used in combination, when the antibacterial rate reaches greater than 90%, i.e. 96.02%, the minimum inhibitory concentration of quercetin drops to 0.109 mg / mL, which is 1 / 8 of the amount of quercetin used in the original quercetin-loaded microemulsion. The minimum inhibitory concentration of camellia saponin drops to 0.781 mg / mL, which is 1 / 32 of the amount of camellia saponin used in the original camellia saponin-loaded microemulsion. Moreover, the microemulsion system excluding the plant extract portion has no inhibitory effect on Propionibacterium acnes.

[0077] Calculate their combined antibacterial index, FICI = MIC 槲联用 / MIC 槲单用 +MIC 皂联用 / MIC 皂单用 =0.156. The criteria for judging the combined antibacterial index of drugs are as follows: synergistic effect: FICI ≤ 0.5; antagonistic effect: FICI ≥ 4; additive effect: 0.5

Claims

1. A microemulsion containing plant extracts for antibacterial and acne-reducing purposes, characterized in that, The antibacterial and acne-removing microemulsion is a microemulsion simultaneously loaded with quercetin and camellia saponin; the raw materials of the microemulsion simultaneously loaded with quercetin and camellia saponin include: camellia oil, deionized water, co-surfactant, surfactant, quercetin, and camellia saponin. The co-surfactant is at least one of ethanol and 1,2-propanediol; the surfactant is Tween 85. The concentration of quercetin was 0.109 mg / mL, and the concentration of camellia saponin was 0.781 mg / mL, with an inhibition rate of over 90% against Propionibacterium acnes. The preparation of the antibacterial and acne-reducing microemulsion containing plant extracts includes the following steps: (1) Camellia oil is thoroughly mixed with Tween 85 and co-surfactant to obtain mixture A, wherein the mass fraction of camellia oil is 10%-50%, the mass fraction of Tween 85 is 40%-72%, and the mass fraction of co-surfactant is 10%-18%; (2) Mix mixture A thoroughly with quercetin to obtain mixture B; (3) Dissolve camellia saponin in deionized water to obtain camellia saponin aqueous solution; (4) Under stirring conditions, add the tea oil saponin aqueous solution dropwise to mixture B until it becomes a clear and transparent microemulsion system.

2. The method for preparing an antibacterial and acne-reducing microemulsion containing plant extracts as described in claim 1, characterized in that, Includes the following steps: (1) Camellia oil is thoroughly mixed with Tween 85 and co-surfactant to obtain mixture A, wherein the mass fraction of camellia oil is 10%-50%, the mass fraction of Tween 85 is 40%-72%, and the mass fraction of co-surfactant is 10%-18%; (2) Mix mixture A thoroughly with quercetin to obtain mixture B; (3) Dissolve camellia saponin in deionized water to obtain camellia saponin aqueous solution; (4) Under stirring conditions, add the tea oil saponin aqueous solution dropwise to mixture B until it becomes a clear and transparent microemulsion system.

3. The method for preparing an antibacterial and acne-removing microemulsion containing plant extracts according to claim 2, characterized in that, In step (4), the obtained microemulsion system is ultrasonically treated and then centrifuged to maintain its clarity, transparency, and stable properties.

4. The method for preparing an antibacterial and acne-removing microemulsion containing plant extracts according to claim 2, characterized in that, The microemulsions obtained in step (4) simultaneously loaded with quercetin and tea oil saponin belong to the oil-in-water system.

5. The method for preparing an antibacterial and acne-removing microemulsion containing plant extracts according to claim 2, characterized in that, In step (4), the microemulsion is obtained by continuous double dilution with nutrient broth.

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