A buddleja officinalis extract with antibacterial activity and a preparation method and application thereof

Abstract

The application discloses a kind of antibacterial activity of bung flower extract and preparation method thereof, the bung flower chemical component is in-depth studied in the application, and the best complex preparation of bung flower volatile oil and bung flower total flavone with best antibacterial activity is screened out, and the emulsion with good antibacterial effect and good stability with bung flower volatile oil and bung flower total flavone as active ingredient is researched.The antibacterial screening result of the application shows that bung flower total flavone and bung flower volatile oil are compounded according to specific weight-volume ratio, and have synergistic effect on staphylococcus aureus, methicillin-resistant staphylococcus aureus, pseudomonas aeruginosa, acinetobacter baumannii and escherichia coli, and good unexpected technical effect is obtained.

Description

Technical Field

[0001] This invention belongs to the field of traditional Chinese medicine technology. Specifically, this invention relates to an extract of Buddleja officinalis with antibacterial activity, its preparation method, and its application. Background Technology

[0002] Buddleja officinalis Maxim., a plant in the Loganiaceae family, is a dried flower bud and inflorescence. The dried flowers or buds are used medicinally. It has a sweet, slightly cold taste, is non-toxic, and enters the liver meridian. It has the effects of dispelling wind, cooling the blood, moistening the liver, and improving eyesight. It is mainly used to treat symptoms such as red, swollen, and painful eyes, corneal opacity, blepharitis, excessive tearing, and photophobia. Buddleja officinalis is a specific ophthalmic medicine used for red, swollen, and painful eyes, excessive eye discharge and tearing, and photophobia. It is often used with Eriocaulon buergerianum and Cicadae Periostracum. It is also used for blurred vision, weakness due to prolonged viewing, or blindness and corneal opacity, and is generally combined with chrysanthemum and wolfberry. For wind-heat invading the body, causing eye discharge, photophobia, eyelid papules, and itchy, swollen, and swollen eyes, it is often used with mulberry leaves and chrysanthemum.

[0003] The flower spike contains various flavonoids such as brucellin and robinin.

[0004] Currently, there are no reports on antibacterial screening experiments of the volatile oil of Buddleja officinalis. This invention conducts in-depth research on the volatile oil and flavonoids of Buddleja officinalis, and screens out a compound preparation of volatile oil and flavonoids of Buddleja officinalis with good antibacterial effects. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to conduct in-depth research on Buddleja officinalis through numerous experiments, screen out the best compound preparation of Buddleja officinalis volatile oil and total flavonoids with the best antibacterial activity, and develop an emulsion prepared from Buddleja officinalis volatile oil and total flavonoids.

[0006] Technical solution: To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0007] An antibacterial extract of Buddleja officinalis, composed of total flavonoids and volatile oil from Buddleja officinalis.

[0008] As a preferred embodiment, the above-mentioned Buddleja officinalis extract with antibacterial activity has a mass-to-volume ratio of total flavonoids and volatile oil of Buddleja officinalis of 1:1, 7.5:20, 3.5:20, 4:20, and 16:20.

[0009] As a preferred embodiment, the above-mentioned extract of Buddleja officinalis with antibacterial activity, wherein the total flavonoids of Buddleja officinalis are prepared by the following method:

[0010] (1) Preparation of crude extract of total flavonoids from Buddleja officinalis

[0011] Weigh an appropriate amount of coarse powder of Buddleja officinalis, add 80% ethanol at a material-to-liquid ratio of 1:10, extract by ultrasonication at 410W for 35 minutes, extract three times consecutively, filter, combine the three filtrates, concentrate by rotary evaporator, dry, and obtain total flavonoids of Buddleja officinalis, store at 4℃ for later use.

[0012] (2) Dissolve the total flavonoid powder of Buddleja officinalis from step (1), load it onto a polyamide chromatographic column, wash away impurities with deionized water, elute with 95% ethanol, collect the 95% ethanol eluent, concentrate under reduced pressure and dry to obtain the total flavonoids of Buddleja officinalis.

[0013] The volatile oil of Buddleja officinalis is prepared by the following method:

[0014] Place the Buddleja officinalis herb in a round-bottom flask, add distilled water until the herb is submerged, first extract with ultrasound, then extract with steam distillation, collect the volatile oil of Buddleja officinalis, and store at 4°C away from light.

[0015] As a preferred embodiment, the above-mentioned extract of Buddleja officinalis with antibacterial activity, wherein the total flavonoids of Buddleja officinalis are prepared by the following method:

[0016] (1) Preparation of crude extract of total flavonoids from Buddleja officinalis

[0017] Weigh an appropriate amount of coarse powder of Buddleja officinalis, add 80% ethanol at a material-to-liquid ratio of 1:6-20, extract by ultrasonication for 10-60 minutes, extract 2-3 times consecutively, filter, combine the filtrates, concentrate by rotary evaporator, dry, and obtain ethanol extract of Buddleja officinalis. Store at 4℃ for later use.

[0018] (2) Take the ethanol extract of Buddleja officinalis from step (1), dissolve it in water, load it onto a polyamide chromatography column, wash away impurities with deionized water, elute with 95% ethanol, collect the 95% ethanol eluent, concentrate it under reduced pressure and dry it to obtain the total flavonoids of Buddleja officinalis.

[0019] The volatile oil of Buddleja officinalis is prepared by the following method:

[0020] Place the Buddleja officinalis herb in a round-bottom flask, add distilled water until the herb is submerged, first extract with ultrasound for 10-30 minutes, then extract with steam distillation for 10-20 hours, collect the volatile oil of Buddleja officinalis, and store at 4°C away from light.

[0021] An antibacterial emulsion of Buddleja officinalis, characterized in that it is prepared by the following method:

[0022] A certain mass-volume ratio of total flavonoids and volatile oil from *Buddleja officinalis* was combined, 70% ethanol was added, and then almond oil was added. The *Buddleja officinalis* emulsion was prepared by high-speed homogenization.

[0023] As a preferred embodiment, the above-mentioned Buddleja officinalis emulsion with antibacterial activity is prepared by the following method:

[0024] A certain mass-volume ratio of 2:1 of total flavonoids and volatile oil of Buddleja officinalis was combined, 70% ethanol was added, and then almond oil was added to make the oil-water ratio 5:5. The pH of the aqueous phase was adjusted to 4.3-5, and Buddleja officinalis emulsion was prepared by high-speed homogenization.

[0025] As a preferred embodiment, the above-mentioned Buddleja officinalis emulsion with antibacterial activity has a total drug loading of 200 mg of total flavonoids and volatile oils from Buddleja officinalis, and the emulsion particle size is 300-500 nm.

[0026] The present invention relates to the application of the Buddleja officinalis extract in the preparation of antibacterial drugs or skin care products. The bacteria mentioned include Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, Corynebacterium banding, Pseudomonas aeruginosa, Acinetobacter baumannii, or carbapenem-resistant Klebsiella pneumoniae.

[0027] This invention allows for the preparation of Buddleja officinalis extract with pharmaceutically acceptable carriers into capsules, tablets, granules, pills, powders, ointments, mixtures, oral liquids, or injections. The skincare products include gels, lotions, sprays, etc.

[0028] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0029] This invention conducts in-depth research on the chemical composition of Buddleja officinalis, screens out the best compound preparation of Buddleja officinalis volatile oil and total flavonoids with the best antibacterial activity, and studies an emulsion with good antibacterial effect and good stability, with Buddleja officinalis volatile oil and total flavonoids as active ingredients.

[0030] The antibacterial screening results of this invention show that the total flavonoids and volatile oil of Buddleja officinalis, when combined in a specific weight-volume ratio, have a synergistic effect against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, and Escherichia coli, achieving excellent and unexpected technical results.

[0031] The Buddleja officinalis emulsion prepared by this invention has good thermal stability and excellent antibacterial activity. Attached Figure Description

[0032] Figure 1 The results of Buddleja officinalis emulsions prepared with different drug loadings and their particle size and emulsion index.

[0033] Figure 2 The results of Buddleja officinalis emulsions prepared with different water-oil ratios and their particle size and emulsion index.

[0034] Figure 3 The latexes of Buddleja officinalis prepared with different aqueous phase pH and their particle size and emulsion index.

[0035] Figure 4 The results of the optimization of the response surface of the emulsion of Buddleja officinalis by the pairwise interaction of various factors.

[0036] Figure 5 The results show the thermal stability of the Buddleja officinalis emulsion.

[0037] Figure 6 The results show the salt ion stability of the Buddleja officinalis emulsion.

[0038] Figure 7 The results show the photostability of the latex from Buddleja officinalis.

[0039] Figure 8 The MICs of total flavonoids and volatile oil from Buddleja officinalis against methicillin-resistant Staphylococcus aureus are shown in the figure.

[0040] Figure 9 The MICs of total flavonoids and volatile oil from Buddleja officinalis against Staphylococcus aureus are shown in the figure.

[0041] Figure 10 The MICs of total flavonoids and volatile oil from Buddleja officinalis against Enterococcus faecalis are shown in the figure.

[0042] Figure 11 The MIC diagrams show the total flavonoids and volatile oils of Buddleja officinalis against Corynebacterium styloides.

[0043] Figure 12 The MICs of total flavonoids and volatile oil from Buddleja officinalis against Pseudomonas aeruginosa are shown.

[0044] Figure 13 The MICs of total flavonoids and volatile oil from Buddleja officinalis against Acinetobacter baumannii are shown in the figure.

[0045] Figure 14 The MICs of total flavonoids and volatile oil from *Buddleja officinalis* against carbapenem-resistant *Klebsiella pneumoniae* are shown.

[0046] Figure 15 The MIC diagrams show the total flavonoids and volatile oil of Buddleja officinalis against Staphylococcus aureus (standard strain).

[0047] Figure 16 The MICs of total flavonoids and volatile oil from Buddleja officinalis against Pseudomonas aeruginosa (standard strain).

[0048] Figure 17 The MIC diagrams show the total flavonoids and volatile oils of Buddleja officinalis against Escherichia coli (standard strain). Detailed Implementation

[0049] The present invention will be further described below with reference to specific embodiments, but these embodiments should not be construed as limiting the present invention.

[0050] Example 1

[0051] An extract of Buddleja officinalis with antibacterial activity, the total flavonoids of Buddleja officinalis, is prepared by the following method:

[0052] 1.1 Preparation of crude extract of total flavonoids from Buddleja officinalis

[0053] Weigh an appropriate amount of coarse powder of Buddleja officinalis, add 80% ethanol at a material-to-liquid ratio of 1:10, and extract by ultrasonic extraction at 410W for 35 minutes. Repeat the extraction three times, filter, combine the three filtrates, concentrate by rotary evaporator, dry, and obtain ethanol extract of Buddleja officinalis. Store at 4℃ for later use.

[0054] 1.2 Purification of total flavonoids from Buddleja officinalis

[0055] Dissolve the ethanol extract powder of Buddleja officinalis from step (1.1), load it onto a polyamide column at a concentration of 200 mg / mL, with a loading flow rate of 1 mL / min, then wash away impurities with 90 mL of deionized water, and elute with 95% ethanol. Collect the 95% ethanol eluent, concentrate it under reduced pressure, and then dry it to obtain the total flavonoids of Buddleja officinalis.

[0056] 1.3 Extraction of volatile oil from Buddleja officinalis

[0057] Place 100g of Buddleja officinalis herb in a round-bottom flask, add distilled water until the herb is submerged, sonicate for 20 minutes, then extract by steam distillation for 20 hours, centrifuge, collect the essential oil, and store at 4°C away from light.

[0058] Example 2

[0059] 1. Determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)

[0060] The MIC was determined using the micro-broth dilution method (96-well plate method). 50 μL of sterile MH broth was added to each well of the 96-well plate; 50 μL of crude extract sample was added from column 3, and the mixture was serially diluted up to column 12, with 50 μL discarded from column 12 (final liquid volume per well was 100 μL); a blank control was prepared in column 1 (only blank broth was added, no bacterial suspension), and a negative control was prepared in column 2 (bacterial suspension was added, no drug solution was added); 100 μL of the test bacterial suspension was added to each well, with a final liquid volume of 200 μL per well, and each strain was replicated three times; after loading the drug and bacterial suspension, the plate was capped and incubated at 37℃ for 24 hours to observe the results.

[0061] Take 100 μL of each culture bottle from which no bacterial growth was observed, spread it on a solid culture medium, and incubate at 37°C for 18 h. The minimum crude extract concentration at which no colony growth was observed is the MBC value of the bacterium. Each bacterium was repeated 3 times, and the average value was calculated.

[0062] 2. Evaluation of the antibacterial activity of the compound of flavonoids and volatile oils from Buddleja officinalis

[0063] Based on the MIC values of buddleja flavonoids and volatile oils, a series of concentrations were prepared and the checkerboard method was used, namely 2MIC, 1 / MIC, 1 / 2MIC, 1 / 4MIC, 1 / 8MIC, 1 / 16MIC, 1 / 32MIC, and they were combined in pairs. The fractional inhibitory concentration index FICI was used as the judgment basis.

[0064] FICI = MIC

[0072] ,

[0073] , , (combined) / MIC A (used alone)+MIC B (combined) / MIC B (used alone)

[0065] The judgment criteria for FICI are as follows: when FICI ≤ 0.5, there is a synergistic effect between the two drugs; when 0.5 < FICI ≤ 1.0, there is an additive effect between the two drugs; when 1.0 < FICI < 4.0, there is no relevant effect between the two drugs; when FICI ≥ 4.0, the two drugs have an antagonistic effect. Based on the FICI judgment criteria, the optimal compound ratio of the drugs was calculated using the test drug combination with the smallest FICI value.

[0066] 3. Preparation of Buddleja Pickering Emulsion

[0067] 3.1 Single - factor Screening

[0068] (1) Influence of drug - loading amount on particle size

[0069] According to the compounding results of total flavonoids and volatile oils, 50, 100, 150, 200, 250 mg of total flavonoid powder and 25, 50, 75, 100, 125 μL of volatile oil were weighed respectively at a ratio of total flavonoids:volatile oil = 2:1 (mg / μL), added to 5 mL of 70% ethanol, and then 5 mL of almond oil was added. Pickering emulsion was prepared by high - speed homogenization method, and left to stand at room temperature. Its formation and preliminary stability were evaluated at 0 d and 30 d respectively.

[0070] (2) Influence of water - to - oil ratio on particle size

[0071] 150 mg of total flavonoids and 75 μL of buddleja volatile oil were weighed, added to 5 mL of 70% ethanol, and 1, 3, 5, 7, 9 mL of oil phase were added respectively, and then different volumes of water phase were added to make the water - to - oil volume ratios 1:9, 3:7, 5:5, 7:3, 9:1, and Pickering emulsion was prepared.

[0072] (3) Influence of water - phase pH on particle size

[0073] Weigh 150 mg of total flavonoids and take 75 μL of volatile oil from Buddleja officinalis, add it to 5 mL of 70% ethanol, then add 5 mL of oil phase, stir magnetically until homogeneous, and add aqueous solutions with pH values ​​adjusted to 1, 3, 5, 7, and 9 respectively using 0.1 mg / mL HCl or 0.1 mg / mL NaOH to prepare Pickering emulsions. Let stand at room temperature, and evaluate the molding and preliminary stability at 0 days and 30 days respectively.

[0074] (4) Methods for measuring particle size

[0075] The particle size of emulsion droplets was determined using a PSS Nicomp 380 laser particle size analyzer via a wet method. 0.1g of emulsion was added to 10ml of distilled water and mixed thoroughly. After the instrument was ready, the refractive index was approximately 25% after adding the sample. The image was allowed to stabilize for ten minutes before the value was read.

[0076] 3.2 Response Surface Optimization Experiment

[0077] Factors were selected based on the results of single-factor experiments, and response surface methodology was conducted to optimize the formulation and process.

[0078] 4. Stability testing of Pickering emulsion from Buddleja officinalis

[0079] 4.1 Light stability test

[0080] Equal volumes of freshly prepared Pickering emulsion were dropped into transparent capped vials and allowed to stand for 24 hours each under no light, natural light, and ultraviolet (UVB) irradiation. This process was repeated three times. The stability of the emulsion was characterized by its appearance, microstructure, and droplet size.

[0081] 4.2 Thermal stability

[0082] The prepared emulsions were heated at 30℃, 60℃, and 90℃ for 30 min, with an unheated emulsion (25℃) used as a control to analyze their thermal stability. The microstructure of the emulsion droplets was observed using an optical microscope, and the droplet size and size distribution of the emulsion were measured using a Rise-2006 laser particle size analyzer.

[0083] 4.3 Ion strength stability test

[0084] Equal volumes of freshly prepared Pickering emulsion were dropped into transparent, capped vials. NaCl powder was added to each portion of the emulsion to achieve NaCl concentrations of 0.0%, 1%, 3%, and 5%, respectively. After the NaCl powder dissolved in the emulsion, the emulsion was allowed to stand for 12 hours. The microstructure of the emulsion droplets was then observed using an optical microscope, and the droplet size and size distribution were measured using a Rise-2006 laser particle size analyzer.

[0085] 5. Experimental Results

[0086] 5.1 Results of antibacterial test

[0087] 5.1.1 The MIC and MBC of total flavonoids from Buddleja officinalis are shown in Table 1.

[0088] Table 1. MIC and MBC (mg / mL) of total flavonoids from Buddleja officinalis

[0089]

[0090]

[0091] 5.1.2 The MIC and MBC of the volatile oil of Buddleja officinalis are shown in Table 2.

[0092] Table 2. MIC and MBC (μL / mL) of volatile oil from Buddleja officinalis

[0093]

[0094] 5.1.3 The optimal FIC index for the compounding of flavonoids and volatile oils from Buddleja officinalis is shown in Table 3 below:

[0095] Table 3. FIC Index of the Optimal Combination of Buddleja officinalis Flavonoids and Volatile Oils

[0096]

[0097]

[0098]

[0099] 5.2 Screening results of Pickering emulsion of Buddleja officinalis

[0100] 5.2.1 Single-factor screening

[0101] (1) Effect of drug loading on Pickering emulsion

[0102] like Figure 1 Pickering emulsions were prepared under conditions of pH 5 and a water-to-oil ratio of 5:5. With increasing drug loading, the particle size and emulsion index showed a trend of first decreasing and then increasing. When the drug loading was 200 mg of total flavonoids from *Buddleja officinalis* and 100 μL of volatile oil from *Buddleja officinalis*, the particle size was 361.96 nm, and the emulsion index was 0.07, indicating that the emulsion reached a relatively stable state.

[0103] (2) Effect of water-oil ratio on Pickering emulsion

[0104] like Figure 2Pickering emulsions were prepared with a drug loading of 200 mg total flavonoids from *Buddleja officinalis* and 100 μL volatile oil from *Buddleja officinalis*, and an aqueous phase pH of 5. With increasing water-to-oil ratio, the particle size and emulsion index showed a trend of first decreasing and then increasing. When the water-to-oil ratio was 5:5, the particle size was 492.60 nm, and the emulsion index was 0.03, indicating that the emulsion reached a relatively stable state.

[0105] (3) Effect of aqueous phase pH on Pickering emulsion

[0106] like Figure 3 Pickering emulsions were prepared under the conditions of 200 mg of total flavonoids from *Buddleja officinalis* and 100 μL of volatile oil from *Buddleja officinalis*, with a water-to-oil ratio of 5:5. With increasing pH of the aqueous phase, the particle size and emulsion index showed a trend of first decreasing and then increasing. When the pH was 5, the particle size was 492.60 nm and the emulsion index was 0.10, indicating that the emulsion reached a relatively stable state.

[0107] 5.2.2 Response Surface Optimization

[0108] Response surface analysis experiments were conducted according to the scheme in Table 4 to screen out the optimal influencing factors.

[0109] Table 4 Experimental Design Scheme for Response Surface Analysis

[0110]

[0111] like Figure 4 The optimal formulation of Pickering emulsion is: drug loading of 195.775 mg, oil-water ratio of 0.069 (-1 is 3:7; 0 is 5:5; 1 is 7:3), aqueous phase pH of 4.365, under which the predicted particle size is 336.342 nm; the optimal preparation process is adjusted according to actual conditions to: drug loading of 200 mg, oil-water ratio of 5:5, aqueous phase pH of 4.3-5.

[0112] 5.3 Results of Pickering Emulsion Stability Test for Buddleja officinalis

[0113] 5.3.1 Thermal stability analysis

[0114] like Figure 5 When the heating temperature was 30℃ and 60℃, the apparent and microscopic states of the emulsion did not change significantly, and the particle size and PDI also did not change significantly. However, when the heating temperature was increased to 90℃, the emulsion began to separate, and the size of the emulsion became inconsistent under microscopic conditions, with the particle size increasing from 376.43 nm to 733.03 nm.

[0115] 5.3.2 Salt Ion Stability Analysis

[0116] like Figure 6 As the NaCl concentration increases, compared with the emulsion without NaCl, when the ionic strength increases from 1% to 5%, the microstructure of the emulsion droplets shows obvious emulsification and demulsification phenomena, and the average particle size shows a gradual increase and tends to stabilize.

[0117] 5.3.3 Light stability analysis

[0118] like Figure 7 When the heating temperature was 30℃, the apparent and microscopic states of the emulsion did not change significantly, and the particle size and emulsion index also did not change significantly. However, when the heating temperature was increased to 60℃, the emulsion changed from a fluid state to a non-flowing gel state, and significant aggregation occurred in the microscopic state.

[0119] 5.4 Evaluation results of the antibacterial activity of Pickering emulsion of Buddleja officinalis

[0120] The results of the antibacterial activity evaluation of Pickering emulsion of Buddleja officinalis are shown in Tables 5 and 6.

[0121] Table 5 Comparison of MIC and MBC of flavonoid extracts and Pickering emulsions

[0122]

[0123] *P<0.05, **P<0.01

[0124] Table 6. Comparison of MIC and MBC differences between volatile oils and Pickering emulsions.

[0125]

[0126]

[0127] *P<0.05, **P<0.01

[0128] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A *Buddleja officinalis* extract with antibacterial activity, characterized in that, The mass-to-volume ratio (mg / μL) of total flavonoids and volatile oil from Buddleja officinalis was 1:1, 7.5:20, 3.5:20, or 16:

20. The total flavonoids from *Buddleja officinalis* were prepared by the following method: (1) Preparation of crude extract of total flavonoids from Buddleja officinalis Weigh an appropriate amount of coarse powder of Buddleja officinalis, add 80% ethanol at a material-to-liquid ratio of 1:6-20, extract by ultrasonication for 10-60 minutes, extract 2-3 times consecutively, filter, combine the filtrates, concentrate by rotary evaporator, dry, and obtain ethanol extract of Buddleja officinalis. Store at 4℃ for later use. (2) Take the ethanol extract of Buddleja officinalis from step (1), dissolve it in water, load it onto a polyamide chromatography column, wash away impurities with deionized water, elute with 95% ethanol, collect the 95% ethanol eluent, concentrate it under reduced pressure and dry it to obtain the total flavonoids of Buddleja officinalis. The volatile oil from *Buddleja officinalis* is prepared by the following method: Place the Buddleja officinalis herb in a round-bottom flask, add distilled water until the herb is submerged, first extract with ultrasound for 10-30 minutes, then extract with steam distillation for 10-20 hours, collect the volatile oil of Buddleja officinalis, and store at 4°C away from light.

2. A latex of Buddleja officinalis with antibacterial activity, characterized in that, It is prepared by the following method: A mixture of total flavonoids and volatile oil of Buddleja officinalis with a mass-to-volume ratio of 2:1 mg / μL was prepared by adding 70% ethanol and almond oil to make the oil-to-water ratio 5:5 and adjusting the pH of the aqueous phase to 4.3-5. The Buddleja officinalis emulsion was prepared by high-speed homogenization. The total flavonoids from *Buddleja officinalis* were prepared by the following method: (1) Preparation of crude extract of total flavonoids from Buddleja officinalis Weigh an appropriate amount of coarse powder of Buddleja officinalis, add 80% ethanol at a material-to-liquid ratio of 1:6-20, extract by ultrasonication for 10-60 minutes, extract 2-3 times consecutively, filter, combine the filtrates, concentrate by rotary evaporator, dry, and obtain ethanol extract of Buddleja officinalis. Store at 4℃ for later use. (2) Take the ethanol extract of Buddleja officinalis from step (1), dissolve it in water, load it onto a polyamide chromatography column, wash away impurities with deionized water, elute with 95% ethanol, collect the 95% ethanol eluent, concentrate it under reduced pressure and dry it to obtain the total flavonoids of Buddleja officinalis. The volatile oil from *Buddleja officinalis* is prepared by the following method: Place the Buddleja officinalis herb in a round-bottom flask, add distilled water until the herb is submerged, first extract with ultrasound for 10-30 minutes, then extract with steam distillation for 10-20 hours, collect the volatile oil of Buddleja officinalis, and store at 4°C away from light.

3. The Buddleja officinalis emulsion with antibacterial activity according to claim 2, characterized in that, The total drug loading of total flavonoids and volatile oils from *Buddleja officinalis* in the emulsion was 200 mg, and the particle size of the emulsion was 300–500 nm.

4. The use of the Buddleja officinalis extract according to claim 1 in the preparation of antibacterial drugs or skin care products.

5. The application according to claim 4, characterized in that, The bacteria mentioned include Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, Corynebacterium banding, Pseudomonas aeruginosa, Acinetobacter baumannii, or carbapenem-resistant Klebsiella pneumoniae.

6. The use of the Buddleja officinalis emulsion as described in claim 2 or 3 in the preparation of antibacterial skin care products.

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