Traditional Chinese medicine composite essential oil microemulsion gel and preparation method and application thereof

Abstract

This invention provides a microemulsion gel of traditional Chinese medicine (TCM) compound essential oils, its preparation method, and its application, relating to the technical field of TCM compound essential oil preparations. Following TCM theory and based on the principle of syndrome differentiation and treatment, this invention yields a microemulsion gel of TCM compound essential oils composed of Bupleurum chinense essential oil, Citrus reticulata peel essential oil, Ligusticum chuanxiong essential oil, Murraya paniculata essential oil, and Nardostachys chinensis essential oil, which has the functions of soothing the liver and regulating qi, promoting blood circulation and relieving pain. Based on single-factor experiments, this invention uses response surface methodology to optimize the formulation of the TCM compound essential oil microemulsion gel, ultimately obtaining a uniform, stable, and easily spreadable microemulsion gel. The TCM compound essential oil microemulsion gel of this invention can effectively improve depressive-like behavior in mice under chronic unpredictable stress and reduce the levels of inflammatory factors in the CUMS mouse model, effectively improving the bioavailability of active ingredients in plant essential oils. This invention provides reference and guidance for the development of new dosage forms for the prevention and treatment of depression and the application of TCM essential oils.

Description

Technical Field

[0001] This invention relates to the field of traditional Chinese medicine compound essential oil preparation technology, specifically to a traditional Chinese medicine compound essential oil microemulsion gel, its preparation method, and its application. Background Technology

[0002] Depression is a common central nervous system disorder, affecting approximately 17% of the world's population. With increasing societal development and rising life pressures, the incidence of depression is gradually increasing. The main symptoms of depression include anhedonia and loss of interest, often accompanied by anxiety, sleep disturbances, and other psychological and physical symptoms of varying degrees. A World Health Organization report indicates that over 700,000 people worldwide commit suicide each year due to depression, a major contributing factor to the rising global mortality rate.

[0003] Currently, clinical treatment for depression mainly includes medication, psychotherapy, and physical therapy. Medication accounts for the majority of treatments, and most clinically used antidepressants are synthetic antidepressants. First-generation synthetic antidepressants were gradually abandoned due to safety concerns, leading to the transition to second-generation synthetic antidepressants. However, second-generation drugs still have drawbacks such as slow onset of action and relatively singular target points. These factors have prompted scientists to develop third-generation antidepressants that are more targeted, more effective, and safer. However, current third-generation antidepressants still suffer from insufficient efficacy and numerous adverse reactions in both short- and long-term treatment, and their safety and tolerability remain controversial. Therefore, the search for natural antidepressants with lower toxicity and higher efficacy has become a new research focus.

[0004] In traditional Chinese medicine, aromatic herbs are collectively referred to as aromatic drugs. Aromatic drugs constitute a significant proportion of Chinese medicinal materials and play an indispensable role in clinical treatment. Utilizing aromatic drugs for enzymatic hydrolysis can improve traditional aromatherapy, allowing aromatic substances to be formulated into inhalers and essential oils for absorption through respiration or skin, thereby relieving stress, treating diseases, and promoting health. In recent years, increasing research has revealed that plant essential oils can exert their effects through inhalation and skin penetration, often serving as an adjunct to antidepressant treatment and showing strong efficacy in individuals with depressive tendencies or those in the early stages of depression. However, due to the clearing effect of the nasal mucosa, essential oils have a short residence time in the nasal mucosa, resulting in low bioavailability. However, with the development of drug formulations, it has been found that microemulsion gel-loaded formulations can prolong the residence time of drugs in the nasal mucosa and improve bioavailability. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a traditional Chinese medicine compound essential oil microemulsion gel with significant antidepressant effects and its preparation method.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention provides a microemulsion gel of traditional Chinese medicine compound essential oil, wherein every 100 parts by weight of the microemulsion gel is composed of the following components by weight percentage: 6-9% of traditional Chinese medicine compound essential oil, 25-35% of surfactant, 12-16% of co-surfactant, 1-5% of humectant, 1-2% of gel matrix, and the balance being purified water.

[0010] Specifically, each 100 parts by weight of the microemulsion gel is composed of the following ingredients by weight percentage: 7.98% herbal compound essential oil, 29.82% surfactant, 14.91% co-surfactant, 3% humectant, 1.5% gel matrix, and the balance being purified water.

[0011] Specifically, the herbal compound essential oil is composed of Bupleurum chinense essential oil, Citrus reticulata peel essential oil, Ligusticum chuanxiong essential oil, Murraya paniculata essential oil, and Nardostachys jatamansi essential oil in a mass ratio of 5-7:3-5:3-5:1-3:1-3; preferably, the herbal compound essential oil is composed of Bupleurum chinense essential oil, Citrus reticulata peel essential oil, Ligusticum chuanxiong essential oil, Murraya paniculata essential oil, and Nardostachys jatamansi essential oil in a mass ratio of 6:4.5:4.5:1.5:1.5.

[0012] Specifically, the surfactant is one of the following: polyoxyethylene 40 hydrogenated castor oil (RH40), Tween-80 (TW-80), Tween-20 (TW-20), Span-80, and polyethylene glycol glycerol caprylate (Labrasol); preferably, the surfactant is TW-80.

[0013] Specifically, the co-surfactant is one of Transcutol P, polyethylene glycol 400 (PEG400), 1,2-propanediol, anhydrous ethanol, and n-butanol; preferably, the co-surfactant is PEG400.

[0014] Specifically, the moisturizer is one of glycerin, trehalose, hyaluronic acid, sorbitol, and urea.

[0015] Specifically, the gel matrix is ​​either Carbomer 934 or Carbomer 940, preferably Carbomer 940.

[0016] This invention also provides a method for preparing a microemulsion gel of traditional Chinese medicine compound essential oil, wherein the microemulsion gel is prepared according to the following steps:

[0017] (1) Preparation of compound essential oil of traditional Chinese medicine: 500g each of Bupleurum chinense, Citrus reticulata peel, Ligusticum chuanxiong, Murraya paniculata, and Nardostachys jatamansi were finely pulverized and passed through a No. 2 sieve to obtain uniform powder; then, each powder was mixed with 9 times its volume of distilled water, and each was placed in an electric heating mantle and soaked for 1 hour to fully saturate it; then glass beads were added and a volatile oil measuring device was connected, and a reflux condenser was installed at the top. The water was heated to gradually boil and maintained at a gentle boil; after 6 hours of continuous extraction, when the volume of the volatile oil no longer increased, Stop heating and allow the system to cool naturally for 30 minutes. Then, record the volume of the volatile oil and collect it. To ensure purity, use anhydrous sodium sulfate to dry the volatile oil. The dried volatile oil is a yellow oily liquid. Store it in a brown bottle and place it in a refrigerator at 4°C for later use. Mix Bupleurum chinense essential oil, Citrus reticulata essential oil, Ligusticum chuanxiong essential oil, Murraya paniculata essential oil, and Nardostachys jatamansi essential oil evenly according to a mass ratio of 5-7:3-5:3-5:1-3:1-3 to obtain a compound essential oil of traditional Chinese medicine.

[0018] (2) Mix the Chinese herbal compound essential oil, surfactant and co-surfactant evenly according to the above mass percentage, slowly add water under magnetic stirring, and continue stirring for more than 40 minutes to obtain a microemulsion solution for later use.

[0019] (3) Add the gel matrix to the microemulsion solution obtained in step (2), mix evenly, allow it to swell overnight, adjust the pH to 6-7 with triethanolamine, then add a humectant, mix evenly and the Chinese herbal compound essential oil microemulsion gel is obtained.

[0020] (III) Beneficial Effects

[0021] The liver governs the free flow of Qi and thrives on smooth circulation. Its meridians extend to the hypochondrium and lower abdomen. If emotions are not properly regulated, the liver Qi loses its smooth flow, leading to stagnation and obstruction of the meridians, resulting in symptoms such as hypochondriac pain, chest tightness, and abdominal distension. Impaired liver function also manifests as depression, irritability, and frequent sighing; a wiry pulse is a sign of liver stagnation. Following the principle of "unblocking stagnant Qi" in the *Neijing* (Inner Canon of Medicine), treatment should focus on soothing the liver and regulating Qi. This invention follows the theories of Traditional Chinese Medicine (TCM) and adheres to the principle of syndrome differentiation and treatment. Based on the fundamental formula of Chaihu Shugan San (Bupleurum Liver-Soothing Powder), it modifies the formula to obtain a TCM compound essential oil microemulsion gel prepared from a combination of Chaihu essential oil, Chenpi essential oil, Chuanxiong essential oil, Jiulixiang essential oil, and Gansong essential oil. In this formula, Chaihu, known for its ability to soothe the liver and relieve stagnation, is used as the principal ingredient; Chenpi, which regulates qi, soothes the liver, and promotes circulation, is used as the assistant ingredient; Chuanxiong, which invigorates blood and qi to relieve pain, works synergistically with Chaihu to alleviate stagnation in the liver meridian and enhances the effects of promoting qi circulation, blood circulation, and pain relief. Jiulixiang, which promotes qi circulation, blood circulation, and relieves pain, and Gansong, which regulates qi, relieves pain, and invigorates the spleen, are used as adjuvant ingredients. Together, these herbs work to soothe the liver, regulate qi, invigorate blood, and relieve pain.

[0022] Based on single-factor experiments, this invention utilizes response surface methodology to optimize the formulation of the herbal compound essential oil microemulsion gel, ultimately obtaining the optimal formulation: 7.98% herbal compound essential oil, 29.82% surfactant, 14.91% co-surfactant, 3% humectant, 1.5% gel matrix, with the remainder being purified water; wherein the surfactant is TW-80, the co-surfactant is PEG 400, the humectant is glycerin, and the gel matrix is ​​carbomer 940; a uniform, stable, and extensible herbal compound essential oil microemulsion gel is thus prepared.

[0023] This invention presents a microemulsion gel containing compound essential oils from traditional Chinese medicine (TCM). This gel effectively improves depressive-like behavior in mice under chronic unpredictable stress and reduces inflammatory cytokine levels in a CUMS mouse model, with significantly enhanced effects compared to direct application of the compound essential oils. It also effectively improves the bioavailability of active ingredients in plant essential oils. The addition of Murraya paniculata and Nardostachys jatamansi essential oils significantly enhances the antidepressant efficacy of the microemulsion gel. All components in this microemulsion gel work synergistically, and none can be omitted. This invention provides a reference for the development of new dosage forms for the prevention and treatment of depression and the application of TCM essential oils. Attached Figure Description

[0024] Figure 1 The microemulsion solutions prepared with different surfactants and traditional Chinese medicine compound essential oils at km=2 are shown.

[0025] Figure 2 The microemulsion solutions prepared with different co-surfactants and compound essential oils of traditional Chinese medicine at km=2 are shown in the following figures.

[0026] Figure 3 Pseudo-ternary phase diagrams for surfactant screening; A: oil phase - RH40 / Transcutol P(2:1) - water; B: oil phase - TW-80 / Transcutol P(2:1) - water; C: oil phase - [RH40 / TW-80(2:1)] / Transcutol P(2:1) - water.

[0027] Figure 4 Pseudo-ternary phase diagrams for surfactant screening: A: Oil phase - TW-80 / 1,2-propylene glycol (2:1) - water; B: Oil phase - TW-80 / PEG 400 (2:1) - water; C: Oil phase - TW-80 / Transcutol P (2:1) - water.

[0028] Figure 5The pseudo-ternary phase diagrams for screening the km value are: A: oil phase - TW-80 / PEG 400 (1:1) - water; B: oil phase - TW-80 / PEG 400 (2:1) - water; C: oil phase - TW-80 / PEG 400 (3:1) - water.

[0029] Figure 6 for Figure 6 A: 3D effect surface plot (particle size); B: Contour plot (particle size); C: 3D effect surface plot (PDI); D: Contour plot (PDI).

[0030] Figure 7 The appearance and particle size distribution of microemulsions containing compound essential oils from traditional Chinese medicine. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] Preparation of compound essential oils from traditional Chinese medicine:

[0034] 500g each of Bupleurum chinense, dried tangerine peel, Ligusticum chuanxiong, Murraya paniculata, and Nardostachys jatamansi were finely pulverized and passed through a No. 2 sieve to obtain uniform powder. Then, each powder was mixed with nine times its volume of distilled water, and each mixture was immersed in an electric heating mantle for 1 hour to ensure thorough saturation. Next, glass beads were added and a volatile oil measuring device was connected, with a reflux condenser installed at the top. The water was heated until it gradually boiled and maintained at a gentle simmer. After 6 hours of continuous extraction, heating was stopped when the volume of the volatile oil no longer increased. The system was allowed to cool naturally for 30 minutes. The volume of the volatile oil was then recorded and collected. To ensure purity, the volatile oil was dried using anhydrous sodium sulfate. The dried volatile oil was a yellow oily liquid, which was stored in a brown bottle and placed in a refrigerator at 4°C for later use. Bupleurum chinense essential oil, tangerine peel essential oil, Ligusticum chuanxiong essential oil, Murraya paniculata essential oil, and Nardostachys jatamansi essential oil were mixed evenly in a mass ratio of 6:4.5:4.5:1.5:1.5 to obtain a compound essential oil of traditional Chinese medicine.

[0035] Example 2

[0036] The difference between this embodiment and Embodiment 1 is that the herbal compound essential oil is obtained by mixing Bupleurum essential oil, Tangerine peel essential oil, Ligusticum chuanxiong essential oil, Murraya paniculata essential oil, and Nardostachys chinensis essential oil in a mass ratio of 5:3:3:1:1.

[0037] Example 3

[0038] The difference between this embodiment and Embodiment 1 is that the herbal compound essential oil is obtained by mixing Bupleurum essential oil, Tangerine peel essential oil, Ligusticum chuanxiong essential oil, Murraya paniculata essential oil, and Nardostachys chinensis essential oil in a mass ratio of 7:5:5:3:3.

[0039] Example 4

[0040] The difference between this embodiment and Embodiment 1 is that the herbal compound essential oil is obtained by mixing Bupleurum essential oil, Tangerine peel essential oil, Ligusticum chuanxiong essential oil, Murraya paniculata essential oil, and Nardostachys chinensis essential oil in a mass ratio of 5.8:4:4.2:2:2.

[0041] Example 5

[0042] This invention provides a method for preparing a microemulsion gel of traditional Chinese medicine compound essential oil, the preparation method comprising the following steps:

[0043] (1) Preparation of compound essential oil from traditional Chinese medicine: 500g each of Bupleurum chinense, Citrus reticulata peel, Ligusticum chuanxiong, Murraya paniculata, and Nardostachys jatamansi were finely pulverized and passed through a No. 2 sieve to obtain uniform powder; then, each powder was mixed with 9 times its volume of distilled water, and each was placed in an electric heating mantle and soaked for 1 hour to fully saturate it; then, glass beads were added and a volatile oil measuring device was connected, and a reflux condenser was installed at the top, and the water was heated to gradually boil and maintained at a gentle boil; after 6 hours of continuous extraction, when the volume of the volatile oil no longer increased, Stop heating and allow the system to cool naturally for 30 minutes. Then, record the volume of the volatile oil and collect it. To ensure purity, use anhydrous sodium sulfate to dry the volatile oil. The dried volatile oil is a yellow oily liquid. Store it in a brown bottle and place it in a refrigerator at 4°C for later use. Mix Bupleurum chinense essential oil, Citrus reticulata essential oil, Ligusticum chuanxiong essential oil, Murraya paniculata essential oil and Nardostachys jatamansi essential oil evenly according to a mass ratio of 6:4.5:4.5:1.5:1.5 to obtain a compound essential oil of traditional Chinese medicine.

[0044] (2) Mix the Chinese herbal compound essential oil, surfactant and co-surfactant evenly according to the above mass percentage, slowly add water under magnetic stirring, and continue stirring for more than 40 minutes to obtain a microemulsion solution for later use.

[0045] (3) Add the gel matrix to the microemulsion solution obtained in step (2), mix evenly, allow it to swell overnight, adjust the pH to 6-7 with triethanolamine, then add a humectant, mix evenly and the Chinese herbal compound essential oil microemulsion gel is obtained.

[0046] Based on single-factor experiments, this invention uses response surface methodology to optimize the formulation of the traditional Chinese medicine compound essential oil microemulsion gel, which is described in detail below.

[0047] 1. Experimental Methods and Results

[0048] 1.1 Selection of Surfactants

[0049] The co-surfactant was Transcutol P, and the oil phase was a compound essential oil of traditional Chinese medicine. Different surfactants (RH40, TW-80, TW-20, Labrasol, Span-80) were investigated.

[0050] Following a km=2 ratio, co-surfactants were prepared into mixed emulsifiers with different surfactants. These mixed emulsifiers were then mixed with traditional Chinese medicine compound essential oils in appropriate proportions, and water was added slowly and uniformly under magnetic stirring for titration. When the surfactants were RH40 and TW-80, the resulting microemulsion solution was homogeneous, clear, and transparent (see...). Figure 1 Therefore, RH40 and TW-80 were initially selected as the surfactants in the formulation.

[0051] 1.2 Selection of Co-surfactants

[0052] The oil phase consisted of compound essential oils from traditional Chinese medicine, and the surfactant was RH40. Different co-surfactants (TranscutolP, PEG 400, 1,2-propanediol, anhydrous ethanol, and n-butanol) were investigated.

[0053] Following the formula km=2, ​​surfactants were mixed with different co-surfactants to prepare mixed emulsifiers. These mixed emulsifiers were then mixed with traditional Chinese medicine compound essential oils in appropriate proportions. Water was then slowly titrated under magnetic stirring, resulting in a homogeneous, clear, and transparent microemulsion (see...). Figure 2 However, considering the biosafety index, Transcutol P, PEG 400, and 1,2-propylene glycol were initially selected as co-surfactants.

[0054] 1.3 Univariate analysis of prescriptions

[0055] 1.3.1 Screening of Surfactants

[0056] The co-surfactant is Transcutol P, the oil phase is a compound essential oil of traditional Chinese medicine, and the surfactants are RH40 and TW-80.

[0057] According to km=2, ​​Transcutol P was mixed with RH40, TW-80, and RH40 / TW-80 (2:1) to prepare mixed emulsifiers. The oil phase and the mixed emulsifier were mixed in proportions of 0.5:9.5, 1:9, 1.5:8.5, 2:8, 2.5:7.5, 3:7, 3.5:6.5, and 4:6. Water was slowly added and titrated until the critical point of clarification followed by turbidity and then clarification was reached. Data were recorded, and a pseudo-ternary phase diagram was plotted. The results are shown in Table 1 and [Table data would be inserted here]. Figure 3This indicates that the microemulsion region area is the largest when TW-80 is used as the surfactant, therefore TW-80 was selected as the surfactant.

[0058] Table 1 Screening of surfactants

[0059] A Oil phase - RH40 / Transcutol P(2:1) - Water 0.0164 B Oil phase - TW-80 / Transcutol P(2:1) - Water 0.0207 C Oil phase - [RH40 / TW-80(2:1)] / Transcutol P(2:1) - Water 0.0150

[0060] 1.3.2 Screening of co-surfactants

[0061] TW-80 was used as the surfactant, the compound essential oil of traditional Chinese medicine was used as the oil phase, and the co-surfactants were TranscutolP, PEG 400 and 1,2-propylene glycol.

[0062] According to km=2, ​​TW-80 was mixed with Transcutol P, PEG 400, and 1,2-propylene glycol to prepare mixed emulsifiers. The herbal compound essential oils were mixed with the mixed emulsifiers in ratios of 0.5:9.5, 1:9, 1.5:8.5, 2:8, 2.5:7.5, 3:7, 3.5:6.5, and 4:6. Water was slowly added and titrated under magnetic stirring until the critical point of clarification followed by turbidity and then clarification was reached. Data was recorded, and a pseudo-ternary phase diagram was plotted using Origin2019 64-bit. The results are shown in Table 2 and... Figure 4 When TW-80 is the surfactant and PEG400 is the co-surfactant, the microemulsion area prepared when the compound essential oil is the oil phase is the largest. Therefore, PEG400 is selected as the co-surfactant.

[0063] Table 2 Screening of co-surfactants

[0064] A Oil phase - TW-80 / 1,2-propylene glycol (2:1) - water 0.0278 B Oil phase-TW-80 / PEG 400(2:1)-water 0.0323 C Oil phase - TW-80 / Transcutol P(2:1) - Water 0.0207

[0065] 1.3.3 Filtering of km values

[0066] Different mixed emulsifiers were prepared by mixing TW-80 and PEG 400 at different km values ​​(km = 1:1, 2:2, 3:1, 4:1). The herbal compound essential oil was mixed with the mixed emulsifier in ratios of 0.5:9.5, 1:9, 1.5:8.5, 2:8, 2.5:7.5, 3:7, 3.5:6.5, and 4:6. Water was slowly added and titrated under magnetic stirring until the critical point of clarification followed by turbidity and then clarification was reached. Data were recorded, and a pseudo-ternary phase diagram was plotted using Origin2019 64-bit. The results are shown in Table 3. Figure 5 The microemulsion prepared with a km=2:1 ratio of surfactant (TW-80) and co-surfactant (PEG 400) yielded the largest microemulsion area. Therefore, km=2 was selected.

[0067] Table 3 Filtering of km values

[0068] A Oil phase-TW-80 / PEG 400(1:1)-water 0.0163 B Oil phase-TW-80 / PEG 400(2:1)-water 0.0323 C Oil phase-TW-80 / PEG 400(3:1)-water 0.0080

[0069] 1.4 Star-shaped design - response surface methodology for optimizing formulation

[0070] 1.4.1 Optimization of Microemulsion Formulas for Traditional Chinese Medicine Compound Essential Oils

[0071] The formulation was optimized using the oil phase ratio (A%) of the compound essential oil of traditional Chinese medicine and the mixed phase ratio (B%) of the mixed emulsifier [TW-80 / PEG 400 (km=2:1)] as factors, and the microemulsion particle size Y1 (nm) and Y2 (PDI) as indicators. The experimental factor levels are shown in Table 4, and the microemulsion star point design table and results are shown in Table 5.

[0072] Table 4. Microemulsion Factor Levels

[0073]

[0074] Table 5. Microemulsion dot design and results

[0075]

[0076] 1.4.2 Data Results and Processing

[0077] The results of the analysis of variance and binomial equation fitting are shown in Tables 6 and 7.

[0078] Table 6. Particle Size-Variance-Analysis Results

[0079] Table 7. Results of PDI-Variance Analysis

[0080]

[0081] 1.4.3 Effect Surface

[0082] When km=2, ​​and the mixed phase ratio is constant, the particle size and PDI gradually increase with the increase of the oil phase ratio; when the oil phase ratio is constant, both the particle size and PDI increase with the increase of the mixed phase ratio, see [reference needed]. Figure 6 The final optimized formulation consisted of: Chinese herbal compound essential oil (7.98%), Tween-80 (29.82%), PEG400 (14.91%), and water (47.29%).

[0083] 1.3.4 Verification Test

[0084] Three parallel validations were performed according to the optimized formulation process. The microemulsions obtained were all clear and transparent, with an average particle size of 20.14 (±0.23 nm), an average PDI value of 0.23 (±0.01), and an average Zeta potential of -18.36 (±4.2), which met the expected results.

[0085] 1.5 Quality Evaluation of Compound Microemulsions of Traditional Chinese Medicine

[0086] 1.5.1 Appearance and physicochemical properties

[0087] The microemulsion of compound essential oils from traditional Chinese medicine prepared according to the prescription is yellow, uniform in appearance, transparent, clear, and has good fluidity (see...). Figure 7 Three microemulsion formulations were prepared in parallel according to the optimized formula. The average particle size was 20.14 (±0.23 nm), the average PDI value was 0.23 (±0.01), the average Zeta potential was -18.36 (±4.2) mV, the average pH was 6.32 (±0.14), the average refractive index was 1.425 (26.3℃), and the average conductivity was 290 μS / cm. This indicates that the essential oil microemulsions prepared by this formula have good physicochemical properties.

[0088] 1.5.2 Stability Assessment

[0089] 1.5.2.1 Centrifugal Stability

[0090] Three groups of volatile oil microemulsions were prepared in parallel at 13000 r·min -1 Centrifuge for 20 minutes under the specified conditions and observe changes in appearance and particle size. The results are shown in Table 8. After centrifugation, the particles were clear and transparent, and there were no significant changes in particle size and PDI, indicating good centrifugal stability.

[0091] Table 8 Centrifugal stability ( n=3)

[0092] 1 Clarity, transparency, uniformity 20.22±0.18 0.21±0.01 2 Clarity, transparency, uniformity 19.96±0.17 0.20±0.01 3 Clarity, transparency, uniformity 20.64±0.21 0.23±0.02

[0093] 1.5.2.2 Temperature stability

[0094] The microemulsion solutions were placed at 4, 25, and 50 °C for 24 h. The results are shown in Table 9. The microemulsions remained clear and transparent at different temperatures, with no significant changes in particle size or PDI, and no stratification or demulsification occurred.

[0095] Table 9 Temperature stability ( n=3)

[0096] 1 Clarity, transparency, uniformity 21.42±0.21 0.23±0.01 2 Clarity, transparency, uniformity 22.64±0.18 0.21±0.01 3 Clarity, transparency, uniformity 21.94±0.26 0.24±0.02

[0097] 1.5.2.3 Dilution Stability

[0098] The microemulsion was diluted with double-distilled water at ratios of 1:100, 1:500, and 1:1000, respectively. The results are shown in Table 10. The microemulsion did not separate into layers, and there were no significant changes in particle size and PDI, indicating good dilution stability.

[0099] Table 10 Dilution stability ( n=3)

[0100] 1 Clarity, transparency, uniformity 22.48±0.24 0.16±0.01 2 Clarity, transparency, uniformity 21.73±0.22 0.19±0.01 3 Clarity, transparency, uniformity 20.15±0.21 0.18±0.01

[0101] 1.6 Preparation of Microemulsion Gel

[0102] 1.6.1 Screening of Gel Matrix Dosage

[0103] Weigh out carbomer 934 and carbomer 940 at mass fractions of 1.0%, 1.5%, and 2.0%, respectively, and add them to 6.0 g of the herbal compound essential oil microemulsion solution. Allow it to swell fully overnight, adjust the pH to 6-7 with triethanolamine, and incubate at 9000 rpm. -1 After centrifugation for 10 min, the properties, viscosity, flowability, stability, and extensibility of the microemulsion gel were evaluated. The results are shown in Table 11.

[0104] Table 11 Screening of Gel Matrix

[0105] Carbomer 934 1.00％ Yellow fluid, clumps weak have Uneven, stratified Difficult to apply Carbomer 934 1.50％ Yellow gel powerful none Uniform, stable, and without stratification EasyPaint Exhibition Carbomer 934 2.00％ Yellow fluid, clumps weak have Uneven, stratified Difficult to apply Carbomer 940 1.00％ Yellow fluid weak have Uniform, stable, and without stratification EasyPaint Exhibition Carbomer 940 1.50％ Yellow fluid weak have Uniform, stable, and without stratification EasyPaint Exhibition Carbomer 940 2.00％ Yellow fluid weak have Uniform, stable, and without stratification EasyPaint Exhibition

[0106] 1.6.2 Screening of humectant content

[0107] We screened the effects of adding 1%, 3%, and 5% glycerin as a moisturizer to a microemulsion gel containing compound essential oils from traditional Chinese medicine. The results showed that when the glycerin content was 1%, the gel's appearance remained unchanged and it had no greasy feel; when the glycerin content was 5%, the gel became slightly greasy and its spreadability decreased; when the glycerin content was 3%, the gel was clear and transparent, with a moderate greasiness and good spreadability. Therefore, a glycerin content of 3% was selected.

[0108] 2. Conclusion

[0109] Based on single-factor experiments, this invention uses response surface methodology to optimize the formulation of the herbal compound essential oil microemulsion gel, ultimately obtaining the optimal formulation of the herbal compound essential oil microemulsion gel, specifically: 7.98% herbal compound essential oil, 29.82% surfactant, 14.91% co-surfactant, 3% humectant, 1.5% gel matrix, and the balance being purified water; wherein the surfactant is TW-80, the co-surfactant is PEG 400, the humectant is glycerin, and the gel matrix is ​​carbomer 940.

[0110] Comparative Example 1

[0111] Microemulsion gel was prepared according to the method described in Example 5. The microemulsion gel formulation was as follows: 7.98% of traditional Chinese medicine compound essential oil, 29.82% of TW-80, 14.91% of PEG 400, 3% of glycerin, 1.5% of carbomer 940, and the balance being purified water. The traditional Chinese medicine compound essential oil was obtained by uniformly mixing Bupleurum chinense essential oil, Citrus reticulata peel essential oil, and Ligusticum chuanxiong essential oil in a mass ratio of 6:4.5:4.5.

[0112] Comparative Example 2

[0113] The difference between this comparative example and Comparative Example 1 is that the herbal compound essential oil is obtained by uniformly mixing tangerine peel essential oil, Sichuan lovage essential oil and cyperus essential oil in a mass ratio of 4.5:4.5:3.

[0114] Test case

[0115] 1. Preparation and grouping of animal models of depression

[0116] SPF-grade female Kunming mice with a body weight of (20±2) g were selected. After 3 days of acclimatization, the mice were randomly divided into four groups according to their body weight: blank group, fluoxetine hydrochloride group (0.0025 mg / g), model group, essential oil (EO) group (the essential oil prepared in Example 1, 0.25 μl / g), essential oil microemulsion gel (EOMG) group (the essential oil microemulsion gel prepared in Example 5 of this invention, 0.25 μl / g), control group 1 (microemulsion gel prepared in Comparative Example 1, 0.25 μl / g), and control group 2 (microemulsion gel prepared in Comparative Example 2, 0.25 μl / g). Each group consisted of 12 mice, and the mice were administered the medication via nasal drops. The control group mice were housed together without any modeling procedure, while the other groups were housed individually and subjected to the CUMS program for modeling: cold water swimming (4℃, 5 min), empty cage, tail clamping (3 min), light-dark reversal (24 h), food and water deprivation for 12 h, moist bedding (12 h), odor stimulation (3 h), restraint (2 h), crowding (12 h), no bedding (24 h), cage tilt at 45° (24 h), noise environment (60 Hz, 1 h), 45℃ heat stimulation (5 min), and cage vibration for 10 min. These stimuli were randomly assigned, and during the stress cycle, unpredictable stimulation methods were used; that is, one of the above stress stimulation methods was randomly selected each day, ensuring that the method was not repeated within a week. Drug administration and modeling were performed simultaneously, and the modeling procedure was not interrupted during drug administration, with continuous modeling and drug administration for 28 days.

[0117] 2. Indicator Detection

[0118] 2.1 Weight Measurement

[0119] Mice were monitored weekly to compare the differences in weight gain among groups, determine the effects of chronic stress on the mice's food intake and growth, and the effect of the herbal compound essential oil microemulsion gel of this invention on body weight.

[0120] 2.2 Sugar water preference rate

[0121] Before the sucrose preference experiment, each group of mice was given one bottle of plain water and one bottle of 1% sucrose solution to drink, allowing them to adapt to the alternating environment of plain water and sucrose solution. After 12 hours of adaptation, all mice were housed individually and fasted from food and water for 12 hours. Each mouse was given one bottle of plain water and one bottle of 1% sucrose solution, and the weight of both bottles was measured. After 12 hours of drinking either the plain water or sucrose solution, the bottles were removed, and their weight was measured again. The difference between the two weight measurements was recorded as the amount of plain water or sucrose solution consumed by the mouse, and the sucrose preference rate was calculated. The baseline value of the sucrose preference rate was determined before modeling, and the sucrose preference rate was determined after modeling.

[0122] Sugar water preference rate = (Consumption of sucrose water / (Consumption of plain water + Consumption of sucrose water)) × 100%

[0123] 2.3 Tail Suspension Test

[0124] Fix the mouse upside down with tape 2 cm behind its tail, with its head 5-6 cm above the horizontal plane. Record the cumulative immobility time of the animal in the last 4 minutes of a 6-minute period.

[0125] 2.4 Splash Test

[0126] Spray a 10% sucrose solution three times consecutively onto the back of the mice near the tail. Then, place the mice back into their original cages and record the grooming time for 5 minutes (the time the mice spend grooming the area where the sucrose solution was sprayed on their backs is recorded as the grooming time). The measurements were taken one week before the sample collection.

[0127] 2.5 ELISA detection of serum inflammatory factor levels

[0128] Two hours after the last administration, blood was collected from the eyeballs of mice, allowed to stand at room temperature for 30 minutes, and then centrifuged at 3500 r / min for 10 minutes (centrifugation radius 7.5 cm). The serum was separated, and the levels of tumor necrosis factor-α (TNF-α), interleukin (IL-18), IL-1β and IL-6 in the serum were determined according to the kit instructions.

[0129] 2.6 Statistical Analysis

[0130] Behavioral measurement data were compiled using Excel and expressed as mean ± standard deviation (x̄ ± s). Statistical analysis was performed using the Prism software package, and one-way ANOVA was used for comparisons among multiple groups. P < 0.05 was considered statistically significant, and P < 0.01 indicated a statistically significant difference.

[0131] 3 Results

[0132] 3.1 Effect of the herbal compound essential oil microemulsion gel of the present invention on the body weight of CUMS mouse model

[0133] The body weight comparisons are shown in Table 12. Before modeling, the body weight difference among the groups was not significant (P > 0.05). After 28 days of CUMS stimulation, compared with the blank group, the body weight of the model group decreased significantly (P < 0.01); compared with the model group, the body weight of the EOMG group increased significantly (P < 0.01); the body weight of the fluoxetine hydrochloride group, EO group, and control groups 1 and 2 also showed an increasing trend, but the results were not significantly different from those of the model group (P < 0.01).

[0134] Table 12 Results of body weight changes in mice in each group ( n=12)

[0135]

[0136]

[0137] Note: Compared with the model group, ## P<0.01, # P<0.05.

[0138] 3.2 Effect of the herbal compound essential oil microemulsion gel of the present invention on the sucrose preference rate in the CUMS mouse model

[0139] As shown in Table 13, before modeling, there was no significant difference in the sucrose preference rate among the groups (P > 0.05). After modeling, compared with the blank group, the sucrose preference rate of the model group was significantly reduced (P < 0.01), and the sucrose preference rates of the other groups also decreased to varying degrees, proving that the modeling was successful. After drug administration, compared with the model group, the sucrose preference rate of the xidosin hydrochloride group and the EOMG group was significantly increased (P < 0.01); compared with the model group, the sucrose preference rate of the EO group was significantly increased (P < 0.05); compared with the model group, the sucrose preference rate of control group 1 and 2 mice was increased, but the difference was not significant (P > 0.05).

[0140] Table 13 Results of sucrose preference rate in each group of mice ( n=12)

[0141] Blank group - 83.79％±2.13 <![CDATA[90.37%±1.71 ## ]]> Model group - 80.35％±7.09 50.36％±8.11 Fluoxetine hydrochloride 0.0025mg / g 85.08％±1.75 <![CDATA[81.01%±4.67 ## ]]> EO group 0.25μl / g 84.62％±2.95 <![CDATA[63.12%±4.93 # ]]> Control group 1 0.25μl / g 83.33±3.06 60.64±5.47 Control group 2 0.25μl / g 82.26±2.57 58.23±4.03 EOMG Group 0.25μl / g 82.94％±2.32 <![CDATA[73.40%±1.12 ## ]]>

[0142] Note: Compared with the model group, ## P<0.01, # P<0.05.

[0143] 3.3 Effect of the herbal compound essential oil microemulsion gel of the present invention on the tail immobility time of the CUMS mouse model

[0144] Table 14 shows that, compared with the blank group, the tail suspension immobility time in the model group was significantly increased (P<0.01). Compared with the model group, the tail suspension immobility time in the sibutramine hydrochloride group and the EOMG group was significantly decreased (P<0.01); compared with the model group, the tail suspension immobility time in the EO group was significantly decreased (P<0.05); compared with the model group, the tail suspension immobility time in control group 1 and 2 was decreased, but the difference was not significant (P>0.05).

[0145] Table 14 Results of tail suspension immobility time in each group of mice ( n=12)

[0146]

[0147]

[0148] Note: Compared with the model group, ## P<0.01, # P<0.05.

[0149] 3.4 Effect of the herbal compound essential oil microemulsion gel of the present invention on grooming time in CUMS mouse model

[0150] As shown in Table 15, compared with the blank group, the grooming time of mice in the model group was significantly reduced (P<0.01). Compared with the model group, the grooming time of mice in the sibutramine hydrochloride group and the EOMG group was significantly increased (P<0.01); compared with the model group, the grooming time of mice in the EO group was significantly increased (P<0.05); compared with the model group, the grooming time of mice in control groups 1 and 2 was increased, but the difference was not significant (P>0.05).

[0151] Table 15 Results of grooming time for mice in each group ( n=12)

[0152] Blank group - 12 <![CDATA[89.92±28.80 ## ]]> Model group - 12 36.33±28.91 Fluoxetine hydrochloride 0.0025mg / g 12 <![CDATA[79.83±18.32 ## ]]> EO group 0.25μl / g 12 <![CDATA[59.08±18.48 # ]]> Control group 1 0.25μl / g 12 52.17±10.38 Control group 2 0.25μl / g 12 50.64±9.27 EOMG Group 0.25μl / g 12 <![CDATA[62.67±15.87 ## ]]>

[0153] Note: Compared with the model group, ## P<0.01, # P<0.05.

[0154] 3.5 Effects of the herbal compound essential oil microemulsion gel of the present invention on inflammatory factors in the CUMS mouse model

[0155] As shown in Table 16, compared with the blank group, the levels of IL-18, IL-6, IL-1β, and TNF-α in the model group mice were significantly increased (P < 0.01); compared with the model group, the serum levels of the inflammatory factor IL-18 in the EO group and the EOMMG group were significantly decreased (P < 0.01), the serum levels of the inflammatory factor IL-6 in the EOMMG group were significantly decreased (P < 0.01), and the serum levels of the inflammatory factor IL-6 in the EO group were significantly decreased (P < 0.05); the serum levels of the inflammatory factor IL-18 in the fluoxetine hydrochloride group, the EO group, and the EOMMG group mice were significantly increased (P < 0.05). The level of the inflammatory factor IL-1β was significantly reduced (P<0.01); the serum inflammatory factor TNF-α level in mice in the fluoxetine hydrochloride and EOMG groups was significantly reduced (P<0.01), and the serum inflammatory factor TNF-α level in EO mice was significantly reduced (P<0.05); compared with the model group, the level of inflammatory factor IL-18 in control group 1 and control group 2 mice was significantly reduced (P<0.05), and the levels of other inflammatory factors TNF-α, IL-6 and IL-1β were reduced, but the levels were not significantly different (P>0.05).

[0156] Table 16 Results of inflammatory factors in mice of each group ( n=12)

[0157] Blank group <![CDATA[61.9±26.24 ## ]]> <![CDATA[42.59±11.2 ## ]]> <![CDATA[39.54±3.37 ## ]]> <![CDATA[329.64±58.14 ## ]]> Model group 230.8±23.14 68.22±8.16 98.08±9.57 689.18±115.62 Fluoxetine hydrochloride 207.37±25.7 62.54±10.02 <![CDATA[69.19±12.34 ## ]]> <![CDATA[502.01±95.92 ## ]]> EO group <![CDATA[131.58±32.23 ## ]]> <![CDATA[52.59±10.26 # ]]> <![CDATA[63.66±11.91 ## ]]> <![CDATA[551.35±42.39 # ]]> Control group 1 <![CDATA[155.39±19.44 # ]]> 60.31±11.75 <![CDATA[72.46±12.57 # ]]> 597.93±47.42 Control group 2 <![CDATA[164.59±21.60 # ]]> 61.24±13.68 <![CDATA[74.83±11.68 # ]]> 608.29±63.64 EOMG Group <![CDATA[105.21±22.38 ## ]]> <![CDATA[46.69±9.96 ## ]]> <![CDATA[48.45±16.08 ## ]]> <![CDATA[405.46±82.26 ## ]]>

[0158] Note: Compared with the model group, ## P<0.01, # P<0.05.

[0159] 4. Conclusion

[0160] This invention follows the theories of Traditional Chinese Medicine (TCM) and adheres to the principle of syndrome differentiation and treatment. Based on the fundamental formula of Chaihu Shugan San (Bupleurum Liver-Soothing Powder), it modifies the formula to obtain a TCM compound essential oil microemulsion gel prepared from a combination of Chaihu essential oil, Chenpi essential oil, Chuanxiong essential oil, Jiulixiang essential oil, and Gansong essential oil. In this formula, Chaihu, known for its ability to soothe the liver and relieve stagnation, is used as the principal ingredient; Chenpi, which regulates qi, soothes the liver, and promotes circulation, is used as the assistant ingredient; Chuanxiong, which invigorates blood and qi to relieve pain, works synergistically with Chaihu to alleviate stagnation in the liver meridian and enhances the effects of promoting qi circulation, blood circulation, and pain relief. Jiulixiang, which promotes qi circulation, blood circulation, and relieves pain, and Gansong, which regulates qi, relieves pain, and invigorates the spleen, are used as adjuvant ingredients. Together, these herbs work to soothe the liver, regulate qi, invigorate blood, and relieve pain.

[0161] Based on the above experimental results, the herbal compound essential oil microemulsion gel of this invention can effectively improve depressive-like behavior in mice under chronic unpredictable stress and reduce the levels of inflammatory factors in the CUMS mouse model. The effect is also improved compared to the direct application of the herbal compound essential oil, effectively enhancing the bioavailability of active ingredients in plant essential oils. Furthermore, the antidepressant effect of the herbal compound essential oil microemulsion gel of this invention is significantly better than that of Comparative Examples 1 and 2, and the Western medicine fluoxetine hydrochloride. The addition of Murraya paniculata essential oil and Nardostachys jatamansi essential oil in this invention greatly enhances the antidepressant efficacy of the herbal compound essential oil microemulsion gel. All components in the herbal compound essential oil microemulsion gel of this invention work synergistically, and none can be omitted. This invention provides a reference and guidance for the development of new dosage forms for the prevention and treatment of depression and the application of herbal essential oils.

[0162] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A microemulsion gel containing compound essential oils from traditional Chinese medicine, characterized in that, The microemulsion gel is composed of the following components per 100 parts by weight: 7.98% herbal compound essential oil, 29.82% surfactant, 14.91% co-surfactant, 3% humectant, 1.5% gel matrix, and the balance being purified water; the herbal compound essential oil is composed of Bupleurum chinense oil, Citrus reticulata peel oil, Ligusticum chuanxiong oil, Murraya paniculata oil, and Nardostachys jatamansi oil in a mass ratio of 6:4.5:4.5:1.5:1.5; the surfactant is TW-80; the co-surfactant is PEG400; the gel matrix is ​​Carbomer 940; and the humectant is glycerin.

2. The preparation method of a traditional Chinese medicine compound essential oil microemulsion gel as described in claim 1, characterized in that, The microemulsion gel was prepared according to the following steps: (1) Preparation of compound essential oil of Chinese medicine: 500g each of Bupleurum chinense, Citrus reticulata peel, Ligusticum chuanxiong, Murraya paniculata and Nardostachys jatamansi were finely pulverized and passed through No. 2 sieve to obtain uniform powder; then, each powder was mixed with 9 times its volume of distilled water and placed in an electric heating mantle for 1 h to fully saturate it; then glass beads were added and a volatile oil measuring device was connected, and a reflux condenser was installed at the top. The water was heated to gradually boil and maintained at a slight boil; after 6 h of continuous extraction, when the volume of volatile oil no longer increased, the heating was stopped and the system was allowed to cool naturally for 30 min; then, the volume of volatile oil was recorded and collected. To ensure purity, the volatile oil was dried using anhydrous sodium sulfate. The dried volatile oil was a yellow oily liquid, which was stored in a brown bottle and placed in a refrigerator at 4°C for later use. Bupleurum chinense essential oil, tangerine peel essential oil, Ligusticum chuanxiong essential oil, Murraya paniculata essential oil, and Nardostachys jatamansi essential oil were mixed evenly in a mass ratio of 6:4.5:4.5:1.5:1.5 to obtain a compound essential oil of traditional Chinese medicine. (2) Mix the Chinese herbal compound essential oil, surfactant and co-surfactant evenly according to the above mass percentage, slowly add water under magnetic stirring, and continue stirring for more than 40 minutes to obtain a microemulsion solution for later use; (3) Add the gel matrix to the microemulsion solution obtained in step (2), mix evenly, allow it to swell overnight, adjust the pH to 6-7 with triethanolamine, then add a humectant, mix evenly and the Chinese herbal compound essential oil microemulsion gel is obtained.

3. The application of the traditional Chinese medicine compound essential oil microemulsion gel as described in claim 1 in the preparation of formulations for improving depression.

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