Combined antibacterial agent containing raspberry extract and sophora japonica rice extract, preparation method and application thereof

Abstract

The present invention belongs to the technical field of natural antibacterial agents, and specifically relates to a combined antibacterial agent containing raspberry extract and sophora japonica rice extract, and a preparation method and application thereof. The combined antibacterial agent is composed of raspberry extract and sophora japonica rice extract in proportion. Raspberry fruit is placed in a microwave extractor for heating pretreatment, crushed, and then ultrasonically extracted, filtered, and the filtrate is purified and freeze-dried to obtain raspberry extract freeze-dried powder. Sophora japonica rice buds are crushed into coarse powder, added with distilled water for ultrasonic extraction, and after the extraction is completed, the filtrate is decompressed and filtered, the filtrate is centrifuged while hot, purified by polyamide, and freeze-dried to obtain Sophora japonica rice extract freeze-dried powder. When the two extracts are combined in a mass ratio of 1:1, the maximum diameter of the antibacterial zone for Escherichia coli can reach 18.06 mm, and the minimum inhibitory concentration is 4.15 mg / mL, providing a green plant antibacterial agent that can be selected for clinical use.

Description

Technical Field

[0001] The invention belongs to the technical field of natural antibacterial agents, and particularly relates to a combined antibacterial agent containing raspberry extract and sophora japonica rice extract, and a preparation method and application thereof. Background Art

[0002] With the abuse of antibiotics and irrational use of immunosuppressants, drug-resistant strains are becoming more and more resistant, and clinical treatment of infectious diseases has generally failed due to increased bacterial resistance. Antibiotic resistance is an extremely severe challenge facing antibacterial drugs. Therefore, finding safe and effective green antibacterial drugs is a new challenge.

[0003] Plant extracts are products made from natural plants, which are extracted and separated through physical and chemical processes to obtain one or more active ingredients in the plants without changing their effective structure. Natural plants have a long history of medicinal use in China, and many varieties have been clinically proven to have antibacterial activity. Due to their wide sources, diverse active ingredients, and low toxicity and side effects, they have shown great potential in the development of green antibiotics.

[0004] Raspberry is the unripe fruit of East China raspberry, which is rich in active ingredients such as alkaloids, polyphenols and flavonoids. It has certain antioxidant, liver-protecting, antibacterial and bactericidal effects, low toxicity and safe use.

[0005] Sophora japonica rice is the dried flowers and buds of the leguminous plant Sophora japonica. It has the effects of clearing the liver and purging fire, reducing vascular permeability, etc. It is rich in flavonoids, including rutin and quercetin. Studies have shown that under acidic conditions, flavonoid rutin can be hydrolyzed into quercetin. Quercetin has anti-inflammatory and antimicrobial activities.

[0006] Although natural medicines have the advantages of low toxicity, greenness, and environmentally friendly preparation in terms of antibacterial properties, their minimum inhibitory concentration is relatively high, which limits their clinical application and promotion. Summary of the invention

[0007] In order to solve the problems of potential drug resistance of current antibacterial agents, the present invention provides a natural, green plant antibacterial substance and an application method thereof.

[0008] The present invention rationally combines different natural plant extracts, and enhances the function of inhibiting Escherichia coli through synergistic enhancement while maintaining the original advantages of greenness and safety, thereby providing a green plant antibacterial agent that can be selected for clinical use.

[0009] In order to achieve the above object, the present invention provides a raspberry and sophora japonica rice antibacterial composition, which consists of raspberry extract and sophora japonica rice extract, and the mass ratio of raspberry extract to sophora japonica rice extract is 1:10-10:1.

[0010] The steps of extracting raspberry extract are as follows:

[0011] (1) Place naturally dried raspberry fruits in a microwave extractor, spread the medicinal materials to a thickness of 0.5 to 1.0 cm, preheat at 100 watts for 2 to 4 minutes, take out the medicinal materials, crush them into coarse powder, and pass them through a 20-mesh sieve.

[0012] (2) Add distilled water with a solid-liquid mass ratio of 1:6 to 1:12 to the raspberry medicinal material powder, place it in an ultrasonic extractor, and perform ultrasonic extraction at a temperature of 30° C. for 20 to 30 minutes.

[0013] (3) After the ultrasonic extraction, the filtrate was filtered under reduced pressure and the filtrate was centrifuged while hot. The centrifugation parameters were a speed of 8000 rpm and a centrifugation time of 8 minutes. The upper layer of the centrifuge was purified with HP50 macroporous resin. The loading ratio (V 覆盆子离心液 / W 大孔树脂 ) is 4:1, and the centrifuged liquid is repeatedly loaded for 3 times. After loading, the sample is allowed to stand for 2 hours, and then eluted with distilled water for 1 column volume and discarded; eluted with 20% ethanol for 4 column volumes, the eluate is collected, the solvent is recovered, and freeze-dried in a freeze dryer to obtain freeze-dried powder of raspberry extract.

[0014] The steps of extracting the Sophora japonica rice extract are as follows:

[0015] (1) The naturally dried flower buds of Sophora japonica rice were crushed into coarse powder, passed through a 20-mesh sieve, and placed in an extraction container. Distilled water with a solid-liquid mass ratio of 1:6 to 1:12 was added to the powder, and 1% hydrochloric acid was added to adjust the pH to 5 to 6, and the powder was immersed in a 30°C water bath for 1 to 2 hours. Subsequently, the powder was transferred to an ultrasonic extractor and ultrasonically extracted for 20 to 30 minutes at a temperature of 30°C.

[0016] (2) After the ultrasonic extraction, the filtrate was filtered under reduced pressure and the filtrate was centrifuged while hot, wherein the centrifugation parameters were a speed of 8000 rpm and a centrifugation time of 8 minutes, and the upper layer of the centrifuge was taken for further purification. The centrifuge was purified by polyamide resin, and the loading ratio (V 槐花米离心液 / W 聚酰胺树脂 ) is 2:1, the centrifuge is repeatedly loaded 4 times, and after loading, it is left to stand for 2.5 hours, and then eluted with distilled water. First, 2 column volumes of distilled water are eluted and discarded; then 2 column volumes of ethanol with a volume concentration of 25% are eluted and discarded; then 3 column volumes of ethanol with a volume concentration of 45% are eluted, the eluate is collected, the solvent is recovered, and it is placed in a freeze dryer for freeze drying to obtain the freeze-dried powder of Sophora japonica rice extract.

[0017] The steps of preparing the antibacterial composition of raspberry and sophora japonica rice are as follows:

[0018] The freeze-dried powder of raspberry extract and the freeze-dried powder of Sophora japonica rice extract were placed in a mortar at a mass ratio of 1:10 to 10:1, and the mixture was gently ground and mixed to obtain an antibacterial composition of raspberry and Sophora japonica rice.

[0019] The combined antibacterial agent of the present invention is used for preparing a medicament for inhibiting Escherichia coli.

[0020] Beneficial Effects

[0021] The invention adopts ultrasonic extraction method to avoid the change of component structure caused by high temperature and long-time extraction. Microwave heating is adopted in the pretreatment of medicinal materials to greatly improve the penetration and solubility of the solvent.

[0022] The invention designs acidification treatment when extracting the sophora japonica rice, so as to ensure that most of the flavonoid components are transferred out in the form of free state.

[0023] When raspberry and Sophora japonica rice are used in combination, the inhibitory effect on Escherichia coli is better than when used alone, indicating that the two extracts have a synergistic effect after combination. The prepared composition not only has good antibacterial activity, but is also green and safe, and the extraction process is relatively environmentally friendly, and it also brings out the potential benefits of the two natural medicinal resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the result diagram of the inhibition zone of the antibacterial agent in Example 1 against Escherichia coli.

[0025] Figure 2 This is the result of the inhibition zone of the antibacterial agent against Escherichia coli when the mass ratio of the two extracts in Example 2 is 1:5 (raspberry: sophora japonica rice).

[0026] Figure 3 This is the result of the inhibition zone of the antibacterial agent against Escherichia coli when the ratio of raspberry powder to distilled water (W:V) is 1:12 in Example 3.

[0027] Figure 4 This is the result diagram of the inhibition zone of the antibacterial agent in comparative example 1 against Escherichia coli.

[0028] Figure 5 This is the result diagram of the inhibition zone of the antibacterial agent in comparative example 2 against Escherichia coli.

[0029] Figure 6 This is the result diagram of the inhibition zone of the antibacterial agent in comparative example 3 against Escherichia coli.

[0030] Figure 7 This is a graph showing the experimental results of the minimum inhibitory concentration of the antibacterial agent in Example 1 against Escherichia coli.

[0031] Figure 8This is a graph showing the experimental results of the minimum inhibitory concentration of the antibacterial agent Escherichia coli when the ratio of raspberry powder to distilled water (W:V) is 1:12 in Example 3. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with embodiments, but is not limited thereto.

[0033] Example 1

[0034] (1) Raspberry pretreatment: The raspberry fruit was naturally dried to remove impurities, and placed in a microwave extractor. The raspberry medicinal material was spread flat with a thickness of 0.6 cm, and preheated at 100 watts for 4 minutes. The medicinal material was taken out, crushed into coarse powder, and passed through a 20-mesh sieve.

[0035] (2) Distilled water with a solid-liquid mass ratio of 1:12 was added to the raspberry medicinal material powder, and the powder was placed in an ultrasonic extractor for ultrasonic extraction at a temperature of 30°C for 30 minutes.

[0036] (3) After the ultrasonic extraction, the filtrate was filtered under reduced pressure, and the filtrate was centrifuged while hot (the centrifugal parameter was a speed of 8000 rpm) for 8 minutes. The centrifuged liquid was purified on HP50 macroporous resin. The loading ratio (V 覆盆子离心液 / W 大孔树脂 ) is 4:1, the centrifuge liquid is repeatedly loaded 3 times, and after loading, it is allowed to stand for 2 hours, and then eluted with distilled water for 1 column volume and discarded; continue to elute with 20% ethanol for 4 column volumes, collect the eluate, recover the solvent, put it into a freeze dryer for freeze drying, and obtain raspberry extract freeze-dried powder.

[0037] (4) The flower buds of Sophora japonica rice were naturally dried, crushed into coarse powder, passed through a 20-mesh sieve, placed in a glass container, and distilled water with a solid-liquid mass ratio of 1:12 was added to the powder, and 1% hydrochloric acid was added to adjust the pH to 5, and immersed in a 30°C water bath for 2 hours. Subsequently, it was transferred to an ultrasonic extractor and ultrasonically extracted for 30 minutes at a temperature of 30°C.

[0038] (5) After the ultrasonic extraction, the filtrate was filtered under reduced pressure, and the filtrate was centrifuged while hot (the centrifugal parameter was a speed of 8000 rpm) for 8 minutes. The centrifuged liquid was purified by polyamide resin. 槐花米离心液 / W Polyamide 树脂 ) is 2:1, the centrifuge is repeatedly loaded 4 times, and after loading, it is left to stand for 2.5 hours, and then eluted with distilled water. First, 2 column volumes of distilled water are eluted and discarded; then 2 column volumes of ethanol with a volume concentration of 25% are eluted and discarded; then 3 column volumes of ethanol with a volume concentration of 45% are eluted, the eluate is collected, the solvent is recovered, and it is placed in a freeze dryer for freeze drying to obtain the freeze-dried powder of Sophora japonica rice extract.

[0039] (6) Preparation of raspberry and sophora japonica rice composition: The above-mentioned freeze-dried powder of raspberry extract and freeze-dried powder of sophora japonica rice extract were placed in a mortar at a ratio of 1:1 (mass ratio), and gently ground and mixed to obtain a raspberry and sophora japonica rice antibacterial composition.

[0040] Antibacterial experiment 1: Inhibition zone experiment

[0041] The experiment was conducted with reference to the standards of the Clinical Laboratory Standards Institute (CLSI). 15 mL of melted nutrient agar medium was added to a sterile plate and allowed to solidify. 10 mL of nutrient agar medium was taken up with a pipette. 6 100uL of CFU / mL Escherichia coli suspension is placed on the plate and evenly coated with a coating rod. The test sample is dissolved in sterile water, ultrasonically dissolved for 10 minutes, and then centrifuged at 9000r / min for 8 minutes, and the supernatant is collected for later use. Take another drug-sensitive paper (6mm in diameter), soak it in the above test sample solution for 30 minutes, take it out, and air-dry it in a sterile environment. The drug-sensitive paper of the test sample and the control group (sterile water) are respectively attached to the plate, with the comparison sample in the center and the test sample placed on the periphery. Incubate in a 37°C incubator for 24 hours, and observe the formation of the inhibition zone on the plate.

[0042] The sensitivity judgment standard of antibacterial effect: the diameter of the antibacterial circle <10mm is judged as low sensitivity and ineffective "-"; 10mm≤antibacterial diameter <15mm is judged as medium sensitivity and effective "+"; 15mm≤antibacterial diameter <20mm is judged as high sensitivity and effective "++"; antibacterial diameter ≥20mm is judged as extremely sensitive and effective "+++". Each test sample must be repeated three times. If there is an inhibitory effect in all three experiments and no antibacterial circle is produced in the negative control group, the experimental result is judged to be qualified.

[0043] The antibacterial results of Example 1 are shown in Tables 1 and Figure 1 .

[0044] Example 2

[0045] The preparation method of this embodiment is the same as that of Example 1, except that when preparing the composition, the mass ratio of the freeze-dried powder of the two extracts of raspberry extract and Sophora japonica rice extract is different. The specific combination ratio and the antibacterial effect on Escherichia coli are shown in Table 1. The antibacterial experimental method is the same as that of Example 1.

[0046] Table 1

[0047] Raspberry Extract: Sophora japonica Rice Extract (W:W) Diameter of inhibition zone (mm) Result determination 1：11 8.11 - 1：10 10.12 + 1：8. 11.36 + 1：5 15.71 ++ 1：1 18.06 ++ 1.5：1 17.81 ++ 6：1 16.93 ++ 10：1 11.62 + 10.5：1 9.44 - 12：1 6.23 -

[0048] As can be seen from Table 1, when the mass ratio of the two compositions is different, the antibacterial effect on Escherichia coli is different. When the ratio of raspberry extract to sophora japonica rice extract (W:W) is 1:11, 10.5:1, and 12:1, respectively, the diameter of the inhibition zone is <10 mm, which is judged as low sensitivity and ineffective "-". When the ratio of raspberry extract to sophora japonica rice extract (W:W) is between 1:10 and 10:1, there is a certain antibacterial effect, especially when the mass ratio of the two extracts is 1:1, the inhibition effect on Escherichia coli is the best, achieving high sensitivity and effectiveness. Therefore, the present invention sets the mass ratio of the final combination of raspberry extract and sophora japonica rice extract to 1:10 to 10:1 (mass ratio).

[0049] Example 3

[0050] The preparation method of this embodiment is the same as that of embodiment 1, except that in the ultrasonic extraction process of raspberry extract, the proportion of distilled water added to the medicinal material powder is different. The specific proportion and the antibacterial effect on Escherichia coli are shown in Table 2. The antibacterial experimental method is the same as that of embodiment 1.

[0051] Table 2

[0052] Raspberry powder: distilled water (W:V) Diameter of inhibition zone (mm) Result determination 1：5 8.48 - 1：6 11.54 + 1：7 11.93 + 1：8 15.39 ++ 1：9 16.71 ++ 1：10 16.93 ++ 1：11 17.88 ++ 1：12 18.06 ++ 1：13 14.44 + 1：14 13.02 +

[0053] As can be seen from Table 2, when the ratio of solvent to medicinal material is different during ultrasonic extraction of raspberry, the antibacterial effect on Escherichia coli is different. When the ratio of raspberry coarse powder to distilled water (W:V) is 1:5, the diameter of the antibacterial circle of the final composition is <10mm, which is judged as low sensitivity and ineffective "-". When the ratio of raspberry coarse powder to distilled water (W:V) is between 1:6 and 1:14, the obtained composition has a certain antibacterial effect, especially when the ratio of the two is 1:8 to 1:12, the inhibition effect on Escherichia coli is the best, reaching high sensitivity and effectiveness. When the ratio of the two is 1:13 and 1:14, although there is also an antibacterial effect, the antibacterial effect is reduced, and the use of a large amount of solvent brings inconvenience to subsequent operations, and is not conducive to economic and environmental protection. Therefore, the present invention sets the ratio of medicinal material amount to solvent in the raspberry ultrasonic extraction process to 1:6 to 1:12 (W:V).

[0054] Example 4

[0055] The preparation method of this embodiment is the same as that of embodiment 1, except that the loading ratio, standing time, and elution solvent concentration of the raspberry extract are different when the raspberry extract is purified by HP50 macroporous resin. The specific antibacterial effect on Escherichia coli is shown in Table 4. The antibacterial experimental method is the same as that of embodiment 1.

[0056] Table 3

[0057]

[0058] As shown in Table 3, when raspberry extract was extracted by ultrasonic wave and purified by HP50 macroporous resin, the antibacterial effect of the antibacterial composition prepared by using raspberry extract obtained by different parameters on Escherichia coli was different. 覆盆子离心液 / W 大孔树脂 ) was 4:1, the centrifuge was repeatedly loaded 3 times, and after loading, it was left to stand for 2 hours, then eluted with distilled water for 1 column volume and discarded; eluted with 20% ethanol for 4 column volumes, the eluate was collected and freeze-dried. The composition finally prepared by this process had an inhibition zone diameter of 18.06 mm, which was highly sensitive and effective.

[0059] Example 5

[0060] The preparation method of this embodiment is the same as that of embodiment 1, except that in the ultrasonic extraction process of the Sophora japonica rice extract, the proportion of distilled water added to the medicinal material powder is different. The specific proportion and the antibacterial effect on Escherichia coli are shown in Table 4. The antibacterial experimental method is the same as that of embodiment 1.

[0061] Table 4

[0062] Sophora japonica rice powder: distilled water (W:V) Diameter of inhibition zone (mm) Result determination 1：5 9.03 - 1：6 10.91 + 1：7 12.72 + 1：8 14.08 + 1：9 15.87 ++ 1：10 15.94 ++ 1：11 16.22 ++ 1：12 18.06 ++ 1：13 15.46 ++

[0063] As can be seen from Table 4, when the ratio of the solvent to the medicinal material is different during the ultrasonic extraction of Sophora japonica rice, the antibacterial effect on Escherichia coli is different. When the ratio of Sophora japonica rice powder to distilled water (W: V) is 1: 5, the diameter of the antibacterial circle of the final composition is < 10 mm, which is judged to be low sensitivity and invalid "-". When the ratio of Sophora japonica rice powder to distilled water (W: V) is between 1: 6 and 1: 13, the obtained composition has a certain antibacterial effect, especially when the ratio of the two is 1: 9 to 1: 12, the inhibition effect on Escherichia coli is the best, reaching high sensitivity and effectiveness. When the ratio of the two is 1: 13, although there is also an antibacterial effect, the antibacterial effect is reduced, and the use of a large amount of solvent brings inconvenience to subsequent operations, and is not conducive to economic and environmental protection. Therefore, the present invention sets the ratio of the amount of medicinal materials to the solvent in the ultrasonic extraction process of Sophora japonica rice to 1: 6 to 1: 12 (W: V).

[0064] Example 6

[0065] The preparation method of this embodiment is the same as that of embodiment 1, except that the loading ratio, standing time, and elution solvent concentration are different when the extract of Sophora japonica rice is purified by polyamide. The specific ratio and the antibacterial effect on Escherichia coli are shown in Table 5. The antibacterial experimental method is the same as that of embodiment 1.

[0066] Table 5

[0067]

[0068] As shown in Table 5, when polyamide is used to purify the Sophora japonica rice extract, the Sophora japonica rice extract obtained with different parameters and the antibacterial compositions prepared therefrom have different antibacterial effects on Escherichia coli. 槐花米离心液 / W Polyamide 树脂 ) is 2:1, the centrifuge is repeatedly loaded 4 times, and after loading, it is left to stand for 2.5 hours, and then eluted with distilled water. First, 2 column volumes of distilled water are eluted and discarded; then 2 column volumes of ethanol with a volume concentration of 25% are eluted and discarded; then 3 column volumes of ethanol with a volume concentration of 45% are eluted, the eluate is collected, the solvent is recovered, and it is placed in a freeze dryer for freeze drying. The composition finally prepared by this process has an inhibition zone diameter of 18.06mm, which is highly sensitive and effective.

[0069] Comparative Example 1

[0070] A raspberry extract, the preparation method is the same as the preparation method of the raspberry extract in Example 1, the difference is that the extract only contains raspberry extract. The antibacterial test method is the same as that in Example 1.

[0071] Comparative Example 2

[0072] A sophora japonica rice extract, the preparation method is the same as the preparation method of the sophora japonica rice extract in Example 1, the difference is that the extract only contains the sophora japonica rice extract. The antibacterial experimental method is the same as that in Example 1.

[0073] Comparative Example 3

[0074] A method for preparing an antibacterial composition, the preparation method is the same as that of Example 1, except that the raspberry fruit is not pre-treated by microwave heating and is directly added to the solvent for extraction. The antibacterial experimental method is the same as that of Example 1.

[0075] Comparative Example 4

[0076] A method for preparing an antibacterial composition, the preparation method is the same as that of Example 1, except that hydrochloric acid is not added to the extraction solvent for acidification during ultrasonic extraction of the sophora japonica rice. The antibacterial experimental method is the same as that of Example 1.

[0077] The antibacterial effects of Comparative Examples 1-4 on Escherichia coli are shown in Table 6.

[0078] Table 6

[0079] Test samples Diameter of inhibition zone (mm) Result determination Comparative Example 1 6.31 - Comparative Example 2 6.14 - Comparative Example 3 11.78 + Comparative Example 4 10.26 +

[0080] As can be seen from Table 6, the diameters of the inhibition zones of Comparative Examples 1-2 are all less than 10 mm, indicating that they have no inhibitory effect on Escherichia coli. By comparing Example 1, it can be explained that when the raspberry extract and the Sophora japonica rice extract are used alone, the inhibitory effect on Escherichia coli is not obvious, and when the two extracts are used in combination, the inhibitory effect on Escherichia coli is significantly improved, indicating that a synergistic effect occurs after the two medicinal extracts are combined. The diameter of the inhibition zone of Comparative Example 3 is 11.78 mm, which is low-sensitivity and effective. Compared with Example 1, the antibacterial effect of the composition of raspberries that have not been pretreated with microwaves is significantly reduced. Similarly, the diameter of the inhibition zone of Comparative Example 4 is 10.26 mm, which is low-sensitivity and effective. Compared with Example 1, when Sophora japonica rice is extracted by ultrasonic wave, if acidification is not added, the dissolution of the effective ingredients is affected and the antibacterial effect is weakened.

[0081] Antibacterial experiment 2: Extract minimum inhibitory concentration (MIC) test

[0082] The experiment was conducted in accordance with the standards of the Clinical Laboratory Standards Institute (CLSI). The test samples were dissolved in sterile water at a certain concentration, ultrasonicated for 10 min to dissolve the samples, and then centrifuged at 9000 r / min for 8 min to collect the supernatant for later use. The E. coli suspension was diluted to 10 with PBS buffer. 6 CFU / mL, for later use. Add equal proportions of broth culture medium and test sample solution in a total volume of 200uL to a 96-well culture plate, and use the two-fold dilution method to dilute the concentrations of the samples to be tested to 33.20, 16.60, 8.30, 4.15, 2.07, 1.04, and 0.52mg / mL (corresponding numbers are 1, 2, 3, 4, 5, 6, and 7, respectively). After repeated blowing to mix evenly, place in a 37°C constant temperature incubator for 24 hours, and use sterile water as a control. Divide the sterile plate into 8 areas and mark them with numbers, with No. 8 as the control group. Add 15mL of melted solid culture medium to the plate and wait for it to solidify. Dip the solution in the 96-well plate with an inoculation loop and draw a line on the plate, invert it in a 37°C incubator for 24 hours, and observe the bacterial growth on the plate.

[0083] The MIC of Example 1 and Example 3 (raspberry powder: distilled water 1:12) against Escherichia coli were determined by this method; the lowest drug concentration that inhibited bacterial growth by more than 80% compared with the growth control was determined as the MIC of the drug. The Escherichia coli suspension without antibacterial substances was used as a negative control in the experiment.

[0084] Depend on Figure 7 and Figure 8 It can be seen that when the concentration of Example 1 and Example 3 (raspberry powder: distilled water is 1:12) is 4.15 mg / mL, the growth of Escherichia coli can be inhibited by about 80%. Therefore, the minimum inhibitory concentration of the antibacterial composition provided by the present invention is 4.15 mg / mL.

Claims

1. A combined antibacterial agent containing raspberry extract and sophora japonica rice extract, characterized in that: The combined antibacterial agent is composed of raspberry extract and sophora japonica rice extract in a mass ratio of 1:10 to 10:1; The extraction method of the raspberry extract comprises: placing naturally dried raspberry fruits in a microwave extractor, preheating at 100 watts for 2 to 4 minutes, taking out the fruits, and crushing them into coarse powder; adding distilled water to the powder, performing ultrasonic extraction, and after the extraction, performing vacuum filtration, centrifuging the filtrate while hot, purifying the supernatant with HP50 macroporous resin, eluting with distilled water for 1 column volume, and discarding it; continuing to elute with 20% ethanol for 4 column volumes, collecting the eluate, recovering the solvent, and placing it in a freeze dryer for freeze drying to obtain freeze-dried raspberry extract powder; The extraction method of the sophora japonica rice extract is as follows: crushing the sophora japonica rice buds into coarse powder, adding distilled water and hydrochloric acid with a mass concentration of 1% to adjust the pH, performing ultrasonic extraction, after the extraction is completed, vacuum filtering, centrifuging the filtrate while hot, taking the upper centrifuge liquid, and purifying it with polyamide resin; first eluting with distilled water for 2 column volumes and discarding it; continuing to elute with ethanol with a volume concentration of 25% for 2 column volumes and discarding it; then eluting with ethanol with a volume concentration of 45% for 3 column volumes, collecting the eluate, recovering the solvent, and putting it into a freeze dryer for freeze drying to obtain the sophora japonica rice extract freeze-dried powder; The combined antibacterial agent is used for preparing a medicament for inhibiting Escherichia coli.

2. The combined antibacterial agent according to claim 1, characterized in that The loading ratio of macroporous resin for purification is: V 覆盆子离心液 / W 大孔树脂 =4:1, the centrifuge solution was loaded repeatedly for 3 times, allowed to stand for 2 hours after loading, and then eluted with distilled water.

3. The combined antibacterial agent according to claim 1, characterized in that The loading ratio for polyamide resin purification is V 槐花米离心液 / W polyamide resin = 2:1, the centrifuge liquid was repeatedly loaded 4 times, and after loading, it was allowed to stand for 2.5 hours, and then eluted with distilled water.

4. The combined antibacterial agent according to claim 1, characterized in that When ultrasonic extraction was performed on raspberry and Sophora japonica rice, the solid-liquid mass ratio was 1:6~1:12, the ultrasonic temperature was 30℃, and the ultrasonic extraction time was 20~30 minutes.

5. The combined antibacterial agent according to claim 1, characterized in that When extracting Sophora japonica rice, add hydrochloric acid to the distilled water used for ultrasonic extraction to adjust the pH to 5-6.

6. A method for preparing the combined antibacterial agent according to claim 1, characterized in that: The preparation method comprises the following steps: placing freeze-dried powder of raspberry extract and freeze-dried powder of sophora japonica rice extract in a mortar according to a mass ratio, grinding and mixing them evenly, and obtaining a raspberry and sophora japonica rice antibacterial composition.

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