A template molecule, molecularly imprinted polymer and its application in separating saponin compounds

Abstract

The present invention relates to a template molecule, a molecularly imprinted polymer, and their use in separating saponin compounds. The molecularly imprinted polymer of the present invention utilizes a virtual template molecule. This template molecule significantly enhances the molecularly imprinted polymer's ability to selectively identify specific types of saponin compounds. The template molecule can be used for the separation, enrichment, and purification of natural saponin compounds such as ginsenoside Rb1, ginsenoside IV, kochiasaponin II, platycodonoside D, saikosaponin A, araliaside A, araliaside B, araliaside C, aescin, sanguisorbaside II, sanguisorbaside I, and kochiasaponin IC from natural product extracts, achieving high enrichment, strong accuracy, and a wide range of applications.

Description

Technical Field

[0001] The present invention belongs to the technical field of plant component purification, and in particular relates to a template molecule, a molecularly imprinted polymer and applications thereof in separating saponin compounds. Background Art

[0002] The roots, stems, and leaves of Panax ginseng (Araliaceae) can be carefully extracted and processed to obtain ginsenosides, which contain eighteen monomeric ginsenosides. Ginsenosides are scarce, and extraction techniques are complex. In recent years, molecular imprinting technology has been widely used in the fields of enrichment and purification, with remarkable results. It has opened up new avenues for the enrichment and purification of saponins, including ginsenosides. A key obstacle to the promotion and application of molecular imprinting technology is its high cost, with the high cost of template molecules accounting for a significant proportion of the extraction cost. Furthermore, the structure of ginsenosides is complex and diverse, and the separation and purification techniques are complex, making the preparation of high-purity ginsenoside monomers even more expensive. Summary of the Invention

[0003] The first object of the present invention is to provide a template molecule to reduce the extraction cost by designing a virtual template molecule.

[0004] The second object of the present invention is to provide a molecularly imprinted polymer prepared from the above template molecule.

[0005] The third object of the present invention is to provide applications of the molecularly imprinted polymer.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A template molecule with the following structural formula:

[0008]

[0009] The preparation method of the molecularly imprinted polymer obtained from the above template molecule comprises the following steps:

[0010] Prepare dispersed phase: mix hydrophilic functional monomer, crosslinking agent, water and template molecule to prepare solution A;

[0011] Prepare the continuous phase: Mix the emulsifier with n-hexane under an inert gas atmosphere to form a continuous phase as solution B;

[0012] Prepare the reverse phase dispersion system: Mix solution A and solution B under an inert gas atmosphere to obtain a white emulsion;

[0013] Polymerization reaction: Mix the white emulsion with the initiator to obtain a polymer microsphere mixture;

[0014] Post-treatment: the polymer microsphere mixture is mixed with methanol, the precipitate is filtered, the template molecules are eluted from the precipitate, and then washed until it becomes neutral, and then dried to a constant weight to obtain molecularly imprinted polymer microspheres.

[0015] As a preferred embodiment of the present invention, in the preparation of the dispersed phase, the hydrophilic functional monomer is one of acrylic acid, allylamine and methacrylic acid.

[0016] As a preferred embodiment of the present invention, in the preparation of the dispersed phase, the crosslinking agent is at least one of N,N'-methylenebisacrylamide, trimethoxypropyl trimethacrylate and divinylbenzene.

[0017] As a preferred embodiment of the present invention, in the dispersed phase, the molar ratio of the hydrophilic functional monomer to the template molecule is 1:4.5-7.5.

[0018] As a preferred embodiment of the present invention, in the preparation of the continuous phase, the emulsifier is at least one of docusate sodium, octylphenol polyoxyethylene ether, and Triton X-100.

[0019] As a preferred embodiment of the present invention, in the polymerization reaction, the initiator is one of potassium persulfate and ammonium persulfate.

[0020] As a preferred embodiment of the present invention, during the polymerization reaction, the polymerization temperature is 35-80°C.

[0021] As a preferred embodiment of the present invention, in the polymerization reaction, the polymerization reaction time is 1 to 4 hours, and stirring is continued during the polymerization reaction.

[0022] The use of the above-mentioned molecular imprinting polymer in the separation of natural saponin compounds is characterized in that the natural saponin compound is one of ginsenoside Rb1, japonicus saponin IV, kochia saponin II, platycodon saponin D, bupleurum saponin A, amaranthin A, amaranthin B, amaranthin C, aescin, sanguisorbaside II, sanguisorbaside I, and kochia saponin IC.

[0023] Beneficial effects of the present invention:

[0024] The molecularly imprinted polymer of the present invention uses ethyl-6-((-8a-(ethoxycarbonyl)-4,4,6a,6b,11,11,14b-heptamethyl-1,2,3,4,4a,5,6,6a,6b,7,8,8a,9,10,11,12,12a,14,14a,14b-eicosylpiperidin-3-yl)oxy)-(2S,3R,4S,5S,6R)-3,4,5-trihydroxytetrahydro-2H-pyran-2-carboxylate as a template molecule. The monomer of the template molecule, by virtue of its built-in hydrogen bond acceptor and significant electronic effect, establishes a strong intermolecular interaction with specific saponin compound molecules and shapes a more selective spatial structure, thereby significantly improving the molecularly imprinted polymer's ability to selectively recognize specific types of saponin compounds. It overcomes the problem of high-purity natural saponin compound target molecules being relatively expensive, can be used for large-scale preparation of molecular imprinting polymers, and significantly reduces the extraction cost of natural saponin compounds.

[0025] The molecularly imprinted polymer for natural saponin compounds prepared by the preparation method of the present invention can increase the adsorption amount of target molecules and improve the purity of natural saponin compounds during application. It can be used for the separation, enrichment and purification of natural saponin compounds in natural product extracts, has high enrichment, strong accuracy and a wide range of applications. It has good adsorption performance for natural saponin compound molecules such as ginsenoside Rb1, japonicus saponin IV, kochia saponin II, platycodon saponin D, bupleuron saponin A, amaranthin A, amaranthin B, amaranthin C, aescin, sanguisorbaside II, sanguisorbaside I and kochia saponin IC, and has broad application prospects in the preparation and detection of natural saponin compounds. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with specific embodiments.

[0027] Example 1

[0028] A template molecule was prepared: ethyl-6-((-8a-(ethoxycarbonyl)-4,4,6a,6b,11,11,14b-heptamethyl-1,2,3,4,4a,5,6,6a,6b,7,8,8a,9,10,11,12,12a,14,14a,14b-eicosylpiperidin-3-yl)oxy)-(2S,3R,4S,5S,6R)-3,4,5-trihydroxytetrahydro-2H-pyran-2-carboxylate, whose structural formula is as follows:

[0029]

[0030] The specific experimental operations are as follows:

[0031] (1) Add 10.0 mmol of D-glucose and 10 mL of acetic anhydride to a round-bottom flask to obtain a mixture, and cool the mixture to 0°C. Then, add 0.1 m of perchloric acid (70 wt%) dropwise to the mixture while stirring. After the addition is completed, continue stirring at 0°C for 5 h to obtain a reaction solution. Dilute the reaction solution with dichloromethane (40 mL). Then wash the diluted reaction solution with water (20 mL), saturated NaHCO3 solution (20 mL) and brine (20 mL), respectively. Dry the organic layer with anhydrous sodium sulfate, and then remove the organic solvent in the organic layer by rotary evaporation to obtain acetyl-protected glucose with a yield of 95%.

[0032] (2) 4.0 mmol of acetyl-protected glucose and 40 mL of dichloromethane were added to a round-bottom flask to obtain a mixed solution. 1.66 mL of a 48% mass fraction boron trifluoride ether solution (Article No.: Titan Technology 01375737) was added dropwise to the mixed solution at 0°C. The mixture was stirred at 0°C for 10 minutes, and then 5.2 mmol of compound B oleanolic acid was added to the mixture. Stirring was then continued at room temperature for 24 hours. After the reaction was completed, the temperature was lowered to 0°C, and 20 mL of a saturated NaHCO3 aqueous solution was added to the mixture at 0°C. The organic layer was washed with water (20 mL x 3). After separation, the aqueous layer was further extracted with 40 mL of dichloromethane. The dichloromethane organic phases were combined, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. Compound C was obtained after column chromatography purification with a yield of 89%.

[0033] (3) 2.5 mmol of compound C was dissolved in a mixture of 25 mL of methanol and 5.0 mL of a 25% by mass aqueous ammonia solution. The mixture was stirred at room temperature for 24 hours and then the solvent was removed under reduced pressure. Compound D was obtained after column chromatography purification with a yield of 96%.

[0034] (3) 2.0 mmol of compound D, 10 mL of deionized water, and 10 mL of acetonitrile were added to a round-bottom flask. 0.6 mmol of 2,2,6,6-tetramethylpiperidinyl oxide (TEMPO), 4.4 mmol of iodophenyl diacetic acid, and 4.0 mmol of NaHCO3 were then added to the reaction system at 0°C with stirring. The resulting mixture was warmed to room temperature and stirred for 2 hours. After the reaction was completed, 0.5 mL of ethanol was added to the reaction flask to quench the reaction, and the reaction solution was washed once with 10 mL of ethyl acetate. The aqueous phase was taken, the pH of the aqueous phase was adjusted to 6.0, the solvent was removed under reduced pressure, and the compound E was purified by column chromatography with a yield of 78%.

[0035] (4) 1.5 mmol of compound E and 10 mL of ethanol were added to a round-bottom flask, followed by the addition of 5 drops of concentrated sulfuric acid. The mixture was refluxed for 8 hours. After completion of the reaction, 20 mL of water was added to the reaction system, and the ethanol was removed under reduced pressure. The aqueous phase was extracted with ethyl acetate (10 mL x 3). The ethyl acetate phases were combined and concentrated under reduced pressure to remove the solvent to obtain a crude product. The target template molecule was purified by column chromatography in a yield of 89%.

[0036] The data is as follows: 1 H NMR(400MHz,DMSO-d6)δ5.21-5.09(m,1H),4.31-4.16(m,2H),4.15-4.09(m,4 H),3.59-3.42(m,1H),3.32-3.19(m,1H),3.17-3.15(m,2H),2.71-2.56(m,1H ),1.92-1.72(m,1H),1.65-1.59(m,4H),1.53-1.42(m,16H),1.42-1.36(m,4H ),1.21-0.92(m,4H),0.97-0.85(m,6H),0.82-0.75(m,9H),0.72-0.69(m,8H). 13 C NMR(101MHz,DMSO-d6)δ179.1,171.3,144.3,122.0,106.0,88.6,76.7,76.0,74.2,72.1,61.8(2C),55.4,47.5,46.2,45.9(2C),41.8(2C) ),41.3,39.2,38.5,36.8(2C),33.8,33.3,30.9(2C),28.0,27.7,26.0,23.9(2C),23.4,23.1,17.3,16.9,15.6,14.5(2C).HRMS(ESI)m / z calcd for C 40 H 64 O9[M+H] + :689.4268,found:689.4264.

[0037] Example 2 Preparation and Performance Testing of Molecularly Imprinted Polymers

[0038] 1. Prepare molecularly imprinted polymers as follows:

[0039] 1.1 Preparation of dispersed phase: 5.5 mmol of allylamine and 27.5 mmol of N,N'-methylenebisacrylamide (MBA) were dissolved in 30 mL of water, and 1 mmol of the template molecule ethyl-6-((-8a-(ethoxycarbonyl)-4,4,6a,6b,11,11,14b-heptamethyl-1,2,3,4,4a,5,6,6a,6b,7,8,8a,9,10,11,12,12a,14,14a,14b-eicosylpiperidin-3-yl)oxy)-(2S,3R,4S,5S,6R)-3,4,5-trihydroxytetrahydro-2H-pyran-2-carboxylate prepared in Example 1 was added and uniformly dispersed. The mixture was magnetically stirred at room temperature for 0.5 h to form a prepolymer to obtain solution A.

[0040] 1.2 Prepare the continuous phase: Dissolve 30 g of docusate sodium (AOT) in 300 mL of n-hexane under a nitrogen atmosphere to form a continuous phase, which is solution B.

[0041] 1.3 Preparation of reverse phase dispersion system: Slowly transfer solution A to solution B under stirring and stir at room temperature for 60 min under nitrogen atmosphere to obtain a white emulsion;

[0042] 1.4 Polymerization: 0.7 mL of 10% (w / v) ammonium persulfate (APS) was added to the white emulsion to initiate the polymerization reaction. The reaction was continued at 65°C and 350 rpm for 2 h to obtain a polymer microsphere mixture.

[0043] 1.5 Post-processing: Add methanol to the polymer microsphere mixture to aggregate and precipitate the polymer. Filter the resulting polymer. Transfer the resulting polymer to a 250-mesh sieve, wash with water to remove fine powder, and dry. Place the dried polymer in a Soxhlet extractor and extract the template molecules using methanol / glacial acetic acid (9:1, v / v). Vacuum dry the polymer at 60°C to constant weight. After drying, separate the imprinted material using sieves of varying mesh sizes to obtain molecularly imprinted polymers of varying sizes.

[0044] 2. Performance Testing

[0045] 2.1 Study on the adsorption performance of ginsenoside Rb1:

[0046] i) Total Saponins Assay (for simplified characterization of ginsenoside Rb1): Prepare a 1.0 mg / mL ginsenoside Rb1 standard solution in methanol. Accurately pipette 20 μL, 40 μL, 80 μL, 120 μL, 160 μL, and 200 μL of the reference solution into stoppered test tubes. Place in a boiling water bath to remove the solvent. Add 0.5 mL of 1 wt% vanillin perchloric acid test solution, mix thoroughly in a 60°C constant-temperature water bath, and heat for 15 minutes. Immediately cool in ice water for 2 minutes, add 5 mL of 77% sulfuric acid solution, and shake well. Use the reagent as a blank. After eliminating bubbles, measure the absorbance at a wavelength of 540 nm using a UV-visible spectrophotometer. Plot a standard curve with absorbance as the y-axis and concentration as the x-axis. Dilute the sample to be tested with methanol to a concentration of 20-200 μg / mL, aspirate 1 mL for testing, and calculate the content using the standard curve.

[0047] ii) Determination of adsorption capacity: Accurately weigh 0.2 g of molecularly imprinted nanospheres and place them in a ground-mouth conical flask. Add 5.0 mL of a 3 mg / mL methanol solution of ginsenoside Rb1. After constant temperature oscillation adsorption for 5 hours, centrifuge and dilute the supernatant with methanol to a concentration of 20-200 μg / mL. Measure the absorbance three times in parallel according to method i, take the arithmetic mean, and calculate the total saponin concentration using a standard curve. The adsorption capacity of the imprinted polymer (61.2 mg / g) was calculated based on the change in the total saponin concentration in the solution before and after adsorption. Calculation formula:

[0048] Q=(C0-C)*V / W

[0049] Where: Q: adsorption capacity per gram of polymer (mg / g);

[0050] C0: original mass concentration of adsorbed compound in equilibrium adsorption experiment (mg / L);

[0051] C: mass concentration of adsorbed compound in the supernatant after adsorption equilibrium is reached (mg / L);

[0052] V: volume of adsorption solution (L);

[0053] W: mass of imprinted polymer (g).

[0054] Experimental Example 1: Investigating the Effects of Different Emulsifiers on Polymer Shape

[0055] Based on the preparation method in Example 2, different emulsifiers were used as dispersions (see Table 1) to obtain molecularly imprinted polymers. The adsorption capacity of ginsenoside Rb1 was measured according to 2.1. The results are shown in Table 1:

[0056] Table 1

[0057]

[0058]

[0059] As shown in Table 1, the molecularly imprinted polymers prepared using docusate sodium (AOT), octylphenol polyoxyethylene ether (OP-10), and Triton X-100 as emulsifiers exhibited strong adsorption capacity for ginsenoside Rb1. However, the molecularly imprinted polymer prepared using Span 80 as an emulsifier exhibited weaker adsorption capacity for ginsenoside Rb1 than the other three polymers.

[0060] Experimental Example 2: Investigating the effects of different functional monomer types and ratios in the dispersed phase preparation step on the properties of molecularly imprinted polymers

[0061] Based on the preparation method in Example 2, different functional monomer types and ratios (see Table 2) were used to obtain different molecularly imprinted polymers, and their adsorption capacity for ginsenoside Rb1 was measured. The results are shown in Table 2:

[0062] Table 2

[0063] Serial number Functional monomer and dosage (molar amount) Polymer adsorption capacity 1 Template molecule / acrylic acid (1:5.5) 49.91mg / g 2 Template molecule / allylamine (1:5.5) 59.07mg / g 3 Template molecule / methacrylic acid (1:5.5) 41.03mg / g 4 Template molecule / allylamine (1:3.5) 16.98mg / g 5 Template molecule / allylamine (1:4.5) 50.24mg / g 6 Template molecule / allylamine (1:6.5) 44.87mg / g 7 Template molecule / allylamine (1:7.5) 37.11mg / g

[0064] As shown in Table 2, when acrylic acid, allylamine, and methacrylic acid were used as hydrophilic functional monomers and the template molecule was combined with them in a molar ratio of 1:5.5, the resulting molecularly imprinted polymers exhibited good adsorption capacity for ginsenoside Rb1. The maximum adsorption capacity, 59.07 mg / g, was achieved when the template molecule and allylamine were combined in a molar ratio of 1:5.5. The adsorption capacity of the resulting molecularly imprinted polymers for ginsenoside Rb1 varied significantly when the template molecule and allylamine were combined at different molar ratios. The adsorption capacity decreased significantly to 16.98 mg / g when the template molecule and allylamine molar ratio was 1:3.5. The adsorption capacity when the template molecule and allylamine molar ratios were 1:4.5 and 1:7.5 was slightly lower than that when the molar ratio was 1:5.5.

[0065] Experimental Example 3: Investigating the Effect of Using Different Crosslinkers in the Dispersed Phase Preparation Step on the Molecularly Imprinted Polymer

[0066] Based on the preparation method in Example 2, different cross-linking agents (see Table 3) were used to obtain different molecularly imprinted polymers, and their adsorption capacity for ginsenoside Rb1 was measured. The results are shown in Table 3:

[0067] Table 3

[0068] crosslinking agent Polymer adsorption capacity N,N'-methylenebisacrylamide (MBA) 59.72mg / g Trimethoxypropyl trimethacrylate (TRIM) 43.89mg / g Divinylbenzene (DVB) 27.44mg / g

[0069] As shown in Table 3, different molecularly imprinted polymers prepared by using N,N'-methylenebisacrylamide and trimethoxypropyl trimethacrylate as cross-linking agents all have good adsorption capacity for ginsenoside Rb1; the molecularly imprinted polymer prepared by divinylbenzene (DVB) has a slightly lower adsorption effect on ginsenoside Rb1 than the other two.

[0070] Experimental Example 4 investigates the effects of different initiators used in the polymerization step on the properties of molecularly imprinted polymers in the preparation method

[0071] Based on the preparation method in Example 2, different initiators (see Table 4) were used to observe the reaction performance of different molecularly imprinted polymers. The results are shown in Table 4:

[0072] Table 4

[0073] initiator Polymerization reaction Potassium persulfate Simple operation, quick response, stable process Ammonium persulfate Simple operation, quick response, stable process

[0074] As shown in Table 4, different molecularly imprinted polymers can be successfully prepared by using potassium persulfate and ammonium persulfate as initiators, and both are simple to operate and have rapid reactions.

[0075] Experimental Example 5 investigates the effects of different reaction conditions in the polymerization step on the properties of molecularly imprinted polymers in the preparation method

[0076] Based on the preparation method in Example 2, different molecularly imprinted polymers were prepared by changing the reaction conditions of the polymerization reaction, including reaction temperature, reaction time, and mechanical stirring speed (see Table 5). The adsorption capacity of ginsenoside Rb1 was measured. The results are shown in Table 5:

[0077] Table 5

[0078]

[0079] As shown in Table 5, molecularly imprinted polymer microspheres can be prepared under the conditions of polymerization temperature of 35-80℃ and reaction time of 1-4h. The best adsorption effect of ginsenoside Rb1 was achieved when the reaction temperature was 65℃ and the reaction time was 2h.

[0080] Example 3 Testing the adsorption performance of the molecularly imprinted polymer obtained in Example 2 on various natural saponins:

[0081] The adsorption performance test of ginsenoside Rb1 was carried out according to the method described in 2.1, except that the test molecule was replaced by an alternative molecule (natural saponin compound molecule) instead of ginsenoside Rb1. The obtained data are shown in Table 6.

[0082] Table 6

[0083] serial number Chemical name CAS number Adsorption capacity (mg / g) 1 Panax notoginseng saponin IV 51415-02-2 56.34 2 Kochia scoparia saponin II 95851-41-5 54.23 3 Platycoside D 58479-68-8 48.09 4 Saikosaponin A 20736-09-8 45.67 5 Araliaside A 7518-22-1 54.11 6 Araliaside B 156980-31-3 51.45 7 Araliaside C 55446-15-6 49.88 8 Aescin 6805-41-0 53.32 9 Sanguisorba officinalis saponin II 35286-59-0 52.66 10 Sanguisorba officinalis saponin I 35286-58-9 50.24 11 Kochia scoparia saponin IC 96990-18-0 48.12

[0084] As can be seen from Table 6, the molecularly imprinted polymer prepared in Example 2 has good adsorption properties for natural saponin compounds including ginsenoside IV, kochia saponin II, platycoside D, bupleurum saponin A, amaranthin A, amaranthin B, amaranthin C, aescin, sanguisorbaside II, sanguisorbaside I, and kochia saponin IC.

[0085] Example 4 Test Application of the Molecularly Imprinted Polymer Obtained in Example 2

[0086] In order to verify the separation performance and application potential of the molecularly imprinted polymer microspheres, the molecularly imprinted polymer microspheres were used as an adsorbent material for internal phase extraction to enrich and separate ginsenoside Rb1 from ginseng medicinal material extract.

[0087] The specific experiments are as follows:

[0088] (1) Preparation of ginseng extract: Weigh 0.5 g of ginseng root (crushed to pass through a 20-mesh sieve), add 80 mL of 60% ethanol solution, and extract under ultrasonic reflux for 0.5 h. After centrifugation, separate the supernatant. Repeat the extraction process three times, combine the supernatants, and concentrate them on a rotary evaporator to obtain ginseng extract (herb: extract = 5:1, W / W). Seal and store at low temperature for later use.

[0089] (2) Adsorption experiment: First, 200 mg of molecularly imprinted polymer was loaded into a solid phase extraction cartridge and activated with 5 mL of methanol. Then, a 5 mg / mL ginseng extract loading solution was prepared with methanol, and 3 mL of the loading solution was loaded onto the cartridge. The cartridge was then washed with 6 mL of methanol and eluted with ethanol-acetic acid (90:10, v / v).

[0090] (3) Result analysis: The collected solution was tested by high performance liquid chromatography according to the detection method of ginsenoside Rb1 in ginseng medicinal materials in the Chinese Pharmacopoeia 2015 edition P8-9. The concentration of ginsenoside Rb1 in the solution before and after adsorption was calculated, and the recovery rate was 79.5%.

[0091] The above is only an embodiment of the present invention and does not limit the scope of patent protection. Those skilled in the art can make non-substantial changes or substitutions based on the present invention and still fall within the scope of patent protection.

Claims

1. A template molecule, characterized in that The structural formula is as follows:

2. A molecularly imprinted polymer prepared from the template molecule according to claim 1, characterized in that: Preparation method thereof The following operations are included: Prepare dispersed phase: mix hydrophilic functional monomer, crosslinking agent, water and template molecule to prepare solution A; Prepare the continuous phase: Mix the emulsifier with n-hexane under an inert gas atmosphere to form a continuous phase as solution B; Prepare the reverse phase dispersion system: Mix solution A and solution B under an inert gas atmosphere to obtain a white emulsion; Polymerization reaction: Mix the white emulsion with the initiator to obtain a polymer microsphere mixture; Post-treatment: the polymer microsphere mixture is mixed with methanol, the precipitate is filtered, the template molecules are eluted from the precipitate, and then washed until it becomes neutral, and then dried to a constant weight to obtain molecularly imprinted polymer microspheres.

3. The molecularly imprinted polymer according to claim 2, wherein In the preparation of the dispersed phase, the hydrophilic functional monomer is one of acrylic acid, allylamine and methacrylic acid.

4. The molecularly imprinted polymer according to claim 2, characterized in that In the preparation of the dispersed phase, the crosslinking agent is at least one of N,N'-methylenebisacrylamide, trimethoxypropyl trimethacrylate and divinylbenzene.

5. The molecularly imprinted polymer according to claim 2, characterized in that In the preparation of the dispersed phase, the molar ratio of the hydrophilic functional monomer to the template molecule is 1:4.5-7.

5.

6. The molecularly imprinted polymer according to claim 2, characterized in that In the preparation of the continuous phase, the emulsifier is at least one of docusate sodium, octylphenol polyoxyethylene ether, and Triton X-100.

7. The molecularly imprinted polymer according to claim 2, characterized in that In the polymerization reaction, the initiator is one of potassium persulfate and ammonium persulfate.

8. The molecularly imprinted polymer according to claim 2, wherein During the polymerization reaction, the polymerization temperature is 35 to 80°C.

9. The molecularly imprinted polymer according to claim 2, characterized in that During the polymerization reaction, the polymerization reaction time is 1 to 4 hours, and stirring is continued during the polymerization reaction.

10. Use of the molecularly imprinted polymer according to any one of claims 2 to 9 in separating natural saponin compounds, characterized in that: The natural saponin compound is one of ginsenoside Rb1, ginsenoside IV, kochia fruit saponin II, platycodon saponin D, bupleurum saponin A, araliaside A, araliaside B, araliaside C, aescin, sanguisorbaside II, sanguisorbaside I, and kochia fruit saponin IC.

Images