Template molecule of multifunctional saponin compound molecularly imprinted polymer, molecularly imprinted polymer and application of molecularly imprinted polymer

Abstract

The invention relates to a template molecule of a multifunctional saponin compound molecularly imprinted polymer, the molecularly imprinted polymer and application of the molecularly imprinted polymer, and belongs to the technical field of plant component refining. According to the molecularly imprinted polymer disclosed by the invention, a virtual template molecule is used, and the template molecule contains a hydrogen bond donor and a relatively strong electronic effect; the natural saponin compound molecules of rhizoma anemarrhenae saponin AIII, rhizoma anemarrhenae saponin BII, rhizoma anemarrhenae saponin BIII, notoginsenoside R1, ginsenoside Rg1, ginsenoside Rg3, ginsenoside Rh2, tribulus terrestris saponin K, tribulus terrestris saponin D, platycodin D, liriope spicata saponin B, polyphyllin I, polyphyllin II and polyphyllin VI can be well adsorbed by the natural saponin compound molecules of the rhizoma anemarrhenae saponin BIII, the ginsenoside Rg1, the ginsenoside Rg3, the ginsenoside Rh2, the tribulus terrestris saponin D, the platycodin D, the liriope spicata saponin B, the polyphyllin I, the polyphyllin II and the polyphyllin VI. The virtual template molecule is low in cost and can be used for large-scale preparation of molecularly imprinted polymers, and the extraction cost of natural saponin compounds is remarkably reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of plant component refining, and in particular relates to a template molecule of a multifunctional saponin compound molecular imprinting polymer, a molecular imprinting polymer and applications thereof. Background Art

[0002] Molecularly imprinted polymers are a new type of enrichment material. They are widely used in biochemical separation and analysis related fields because of their stable material structure and specificity in identifying targets. By selecting and optimizing the template molecule, functional polymerization unit, and pore-forming agent system, the selectivity of molecularly imprinted polymers can be regulated to have selective recognition capabilities of different widths to meet different application requirements. In the field of cosmetics, steroidal saponins, as a relatively safe, stable, and effective skin care ingredient, have great application value. However, they are difficult to industrialize due to the difficulty of separation. This is because various steroidal saponins have similar structures in plants, and it is difficult to separate high-purity monomers of a specific steroidal saponin from them.

[0003] In summary, the design and preparation of a molecular imprinting polymer for the enrichment, purification, and analysis of specific types of steroidal saponins has great research potential and commercial value. Summary of the invention

[0004] The first object of the present invention is to provide a template molecule of a multifunctional saponin compound molecular imprinting polymer, and to reduce the extraction cost by designing a virtual template molecule.

[0005] The second object of the present invention is to provide a molecularly imprinted polymer prepared by the above template molecule.

[0006] The third object of the present invention is to provide the application of the molecularly imprinted polymer.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A template molecule of a multifunctional saponin compound molecular imprinting polymer, the structural formula of which is as follows:

[0009]

[0010] The molecularly imprinted polymer prepared by the above template molecule comprises the following steps:

[0011] Prepare dispersed phase: mix hydrophilic functional monomer, crosslinking agent, water and template molecule to form solution A;

[0012] Prepare the continuous phase: Mix the emulsifier and n-hexane under an inert gas atmosphere to form a continuous phase as solution B;

[0013] Preparation of inverse dispersion system: Mix solution A and solution B under an inert gas atmosphere to obtain a white emulsion;

[0014] Polymerization reaction: Mix the white latex with the initiator to obtain a polymer microsphere mixture;

[0015] Post-treatment: Mix the polymer microsphere mixture with methanol, filter out the precipitate, wash the precipitate to neutrality after eluting the template molecules, and then dry it to constant weight to obtain molecularly imprinted polymer microspheres.

[0016] As a preferred embodiment of the present invention, in preparing the dispersed phase, the hydrophilic functional monomer is one of acrylamide, allylamine and methacrylic acid.

[0017] As a preferred embodiment of the present invention, in preparing the dispersed phase, the crosslinking agent is at least one of N,N'-methylenebisacrylamide, polyethylene glycol dimethacrylate and divinylbenzene.

[0018] As a preferred embodiment of the present invention, in preparing the dispersed phase, the molar ratio of the hydrophilic functional monomer to the template molecule is 1:4.5-8.5.

[0019] As a preferred embodiment of the present invention, in the preparation of the continuous phase, the emulsifier is at least one of docusate sodium and polyoxyethylene lauryl ether.

[0020] As a preferred embodiment of the present invention, in the polymerization reaction, the initiator is one of potassium persulfate, benzoyl peroxide and ammonium persulfate.

[0021] As a preferred embodiment of the present invention, in the polymerization reaction, the polymerization reaction temperature is 30 to 90°C.

[0022] 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.

[0023] The application of the molecular imprinting polymer in separating natural saponin compounds, wherein the natural saponin compounds are timosaponin AIII, timosaponin BII, timosaponin BIII, notoginsenoside R1, ginsenoside Rg1, ginsenoside Rg3, ginsenoside Rh2, tribulus terrestris saponin K, tribulus terrestris saponin D, platycodon saponin D, ophiopogon saponin B, paridis saponin I, paridis saponin II, and paridis saponin VI.

[0024] Beneficial effects of the present invention:

[0025] The molecular imprinting polymer of the present invention uses (2R,3R,4S,5R,6R)-2-(hydroxymethyl)-6-(((2aR,4S,6aS,6bS,8aS,8bR,9S,10R,11aS,12aS,12bR)-5',6a,8a,9-tetramethylcosylspiro[naphtho[2',1':4,5]indeno[2,1-b]furan-10,2'-pyran]-4-yl)oxy)tetrahydro-2H-pyran-3,4,5-triol as It is a template molecule, which contains hydrogen bond donors and strong electronic effects, and can react with 14 specific target products, including Anemarrhena saponin AIII, Anemarrhena saponin BII, Anemarrhena saponin BIII, Panax notoginseng saponin R1, Ginsenoside Rg1, Ginsenoside Rg3, Ginsenoside Rh2, Tribulus saponin K, Tribulus saponin D, Platycodon saponin D, Ophiopogon saponin B, Paris saponin I, Paris saponin II, Paris saponin VI, to form non-covalent bonds such as hydrogen bonds and hydrophobic interactions to form multiple action sites. In the separation process, because the molecular imprinting polymer can form a strong intermolecular force and a more specific spatial pocket with a specific type of saponin compound, it has a high selectivity and separates a specific type of saponin compound from natural products. In addition, the virtual template molecule is low in cost and can be used for large-scale preparation of molecular imprinting polymers, which significantly reduces the extraction cost of natural saponin compounds.

[0026] The molecularly imprinted polymer of 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, and can be used for separation, enrichment and purification of natural saponin compounds in natural product extracts, with high enrichment, strong accuracy and wide application range, and has good adsorption performance for natural saponin compound molecules of timosaponin AIII, timosaponin BII, timosaponin BIII, notoginsenoside R1, ginsenoside Rg1, ginsenoside Rg3, ginsenoside Rh2, tribulus terrestris saponin K, tribulus terrestris saponin D, platycodon saponin D, ophiopogon saponin B, parisosaponin I, parisosaponin II and parisosaponin VI. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with specific implementation methods.

[0028] Example 1

[0029] A template molecule (2R, 3R, 4S, 5R, 6R)-2-(hydroxymethyl)-6-(((2aR, 4S, 6aS, 6bS, 8aS, 8bR, 9S, 10R, 11aS, 12aS, 12bR)-5', 6a, 8a, 9-tetramethyl docosyl spiro[naphtho[2', 1': 4, 5] indeno[2, 1-b] furan-10, 2'-pyran]-4-yl)oxy)tetrahydro-2H-pyran-3, 4, 5-triol was prepared, and its structural formula is:

[0030]

[0031] The specific experimental operations are as follows:

[0032] (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 a rotary evaporator to obtain acetyl-protected glucose with a yield of 96%.

[0033] (2) Add 4.0 mmol of compound A acetyl-protected glucose and 40 mL of dichloromethane to a round-bottom flask, and add 1.66 mL of 48% mass fraction boron trifluoride ether solution (Cat. No.: Titan Technology 01375737) dropwise to the mixed solution at 0°C. After stirring the mixture at 0°C for 10 minutes, add 5.2 mmol of compound B (Sarsasapogenin; CAS No.: 82597-74-8) to the mixture, then warm to room temperature and continue stirring for 24 hours. After the reaction is completed, add 20 mL of saturated NaHCO3 aqueous solution to the mixture at 0°C, and wash the organic layer with water (20 mL×3). After separation, further extract the aqueous layer with 40 mL of dichloromethane. The combined dichloromethane organic phase is dried over anhydrous sodium sulfate and concentrated under reduced pressure. Compound C is obtained after column chromatography purification with a yield of 85%.

[0034] (3) 3.0 mmol of compound C was dissolved in a mixture of 20 mL of methanol and 3.0 mL of 25% by mass aqueous ammonia solution. The mixture was stirred at room temperature overnight and then the solvent was removed under reduced pressure. The template molecule was purified by column chromatography with a yield of 91%.

[0035] The template molecular map data is as follows: 1H NMR (400MHz, CDCl3) δ5.50-5.39(m,1H),4.78,(s,1H),4.68,(s,2H),4.55(m,1H),4.40(m,1H),4.10(m,1H),3.95(dd,J =11.0,2.7Hz,1H),3.65(m,6H),3.30(d,J=11.0Hz,1H),2.28(m,2H),2.12(m,2H),2.09-1.95(m,5H),1.88(m,2H),1.85 -1.65(m,6H),1.60-1.35(m,4H),1.33-1.27(m,2H),1.26-1.09,(m,4H),1.08 -1.02,(d,J=7.1Hz,3H),1.02-0.98(d,J=6.9Hz,3H),0.97(s,3H),0.76(s,3H). 13 C-NMR (100MHz, CDCl3,) δ118.9,109.7,81.8,81.0,76.6,74.3,71.6,67.1,65.1,62.3,62.1,56.5,42.1,40.3,39. 8(2C),36.5,35.3(2C),33.5(2C),29.9,27.8(2C),27.1(2C),26.5(2C),23.9,20.8,16.5(2C),14.3.HRMS(ESI)m / z calcd for C 33 H 54 O8[M+H] + :579.3824,found:579.4028.

[0036] Example 2 Preparation and performance testing of molecularly imprinted polymers

[0037] 1. Prepare molecularly imprinted polymers, the steps are as follows:

[0038] 1.1 Preparation of dispersed phase: 6.5 mmol methacrylic acid and 32.5 mmol N, N'-methylenebisacrylamide (MBA) were dissolved in 35 mL water, and 1 mmol of the template molecule (2R, 3R, 4S, 5R, 6R)-2-(hydroxymethyl)-6-(((2aR, 4S, 6aS, 6bS, 8aS, 8bR, 9S, 10R, 11aS, 12aS, 12bR)-5', 6a, 8a, 9-tetramethyl docosyl spiro[naphtho[2', 1': 4, 5] indeno[2, 1-b] furan-10, 2'-pyran]-4-yl)oxy)tetrahydro-2H-pyran-3, 4, 5-triol prepared in Example 1 was added, uniformly dispersed, and magnetically stirred at room temperature for 0.5 h to form a prepolymer to obtain solution A;

[0039] 1.2 Preparation of the continuous phase: Preparation of the continuous phase: 13 g of sodium docusate (AOT) and 25 g of L4 polyoxyethylene lauryl ether (BRIJ 30) were dissolved in 500 mL of n-hexane under a nitrogen atmosphere to form a continuous phase, which was used as solution B;

[0040] 1.3 Preparation of reverse phase dispersion system: slowly transfer solution A to solution B while stirring, and stir at room temperature for 60 min under nitrogen atmosphere to obtain a white emulsion;

[0041] 1.4 Polymerization reaction: 0.8 mL of 10% (w / v) ammonium persulfate (APS) was added to the white emulsion to initiate the polymerization reaction, and the reaction was continued at 50° C. and 320 r / min for 3 h to obtain a polymer microsphere mixture;

[0042] 1.5 Post-treatment: Methanol was added to the polymer microsphere mixture to aggregate and precipitate the polymer, and the polymer was filtered to obtain the polymer. The mixture was transferred to a 270-mesh sieve, washed with water to remove fine powder, and then dried. The dried polymer was placed in a Soxhlet extractor, and the template molecules in the polymer were extracted with ethanol / glacial acetic acid (9:1, V / V). The polymer was vacuum dried at 55°C to constant weight. After drying, the imprinted material was classified with sieves of different mesh sizes to obtain molecular imprinted polymers of different sizes.

[0043] 2. Performance Testing

[0044] 2.1 Study on the adsorption performance of ginsenoside Rg3:

[0045] i) Total saponin detection method (for simplified characterization of ginsenoside Rg3): Prepare 500 μg / mL oleanolic acid standard solution with methanol as solvent, accurately draw 40, 60, 100, 120, 200 μL of reference solution, place in 10 mL stoppered test tubes, place in boiling water bath to evaporate the solvent, add 0.2 mL of newly prepared 5 wt% vanillin-glacial acetic acid solution, shake well, add 0.8 mL of perchloric acid, shake well, place in 70°C constant temperature water bath to mix well, heat for 30 minutes, immediately cool with ice water for 5 minutes, add glacial acetic acid to 10 mL, shake well; use reagent as blank. After eliminating bubbles, use ultraviolet spectrophotometer to measure absorbance at a wavelength of 546 nm, and draw a standard curve with absorbance as ordinate and concentration as abscissa. Dilute the sample to be tested with methanol to a concentration of 20-100 μg / mL, take 1 mL for detection, and calculate the content through the standard curve.

[0046] ii) Determination of adsorption amount: Accurately weigh 0.2g of molecular imprinted polymer and place it in a ground-mouth conical flask, add 5.0mL of ginsenoside Rg3 methanol solution with a concentration of 3mg / mL, and adsorb at a constant temperature for 5h after oscillation. Centrifuge and dilute the supernatant with methanol to a concentration of 20-100μg / mL. Then measure the absorbance three times in parallel according to method i, take the arithmetic mean, and calculate the total saponin concentration using the standard curve. The adsorption amount of the imprinted polymer (60.7mg / g) was calculated based on the change in the total saponin concentration in the solution before and after adsorption. Calculation formula:

[0047] Q=(C0-C)*V / W

[0048] Where: Q: adsorption amount per gram of polymer (mg / g);

[0049] C0: original mass concentration of adsorbed compound in equilibrium adsorption experiment (mg / L);

[0050] C: mass concentration of adsorbed compound in the supernatant after reaching adsorption equilibrium (mg / L);

[0051] V: volume of adsorption solution (L);

[0052] W: mass of imprinted polymer (g).

[0053] Experimental Example 1: Investigating the Effect of Different Emulsifiers on Polymer Shape

[0054] Based on the preparation method in Example 2, different emulsifiers were used as dispersions (see Table 1) to obtain molecularly imprinted polymers. The adsorption amount of ginsenoside Rg3 was measured, and the results are shown in Table 1:

[0055] Table 1

[0056] Emulsifier Polymer adsorption Docusate Sodium(AOT) 59.43mg / g L4 Polyoxyethylene Laureth Ether (BRIJ 30) 52.90mg / g Triton X 100 24.05mg / g

[0057] As shown in Table 1, the molecular imprinted polymers prepared by using docusate sodium (AOT) and L4 polyoxyethylene lauryl ether (BRIJ 30) as emulsifiers have strong adsorption capacity for ginsenoside Rg3. The molecular imprinted polymers prepared by using Triton X100 as an emulsifier have slightly lower adsorption capacity for ginsenoside Rg3 than the other two.

[0058] Experimental Example 2 Investigating the effects of different functional monomer types and proportions used in the dispersed phase preparation step on the properties of molecularly imprinted polymers

[0059] 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 amounts for ginsenoside Rg3 were measured. The results are shown in Table 2:

[0060] Table 2

[0061] As shown in Table 2, when acrylamide, allylamine and methacrylic acid are selected as hydrophilic functional monomers and the template molecule is used in combination with them in a molar ratio of 1:6.5, the prepared molecular imprinted polymer has a good adsorption capacity for ginsenoside Rg3. When the template molecule is used in combination with methacrylic acid in a molar ratio of 1:6.5, the adsorption capacity is the largest, which is 61.24 mg / g. When the template molecule and acrylamide are used in combination at different molar ratios, the adsorption capacity of the prepared molecular imprinted polymer for ginsenoside Rg3 changes greatly. When the molar ratio of the template molecule to acrylamide is 1:2.5, the adsorption capacity is significantly reduced to 16.70 mg / g. When the molar ratio of the template molecule to acrylamide is 1:4.5 and 1:8.5, the adsorption capacity is slightly lower than that when the molar ratio is 1:6.5.

[0062] Experimental Example 3 Investigating the Effect of Using Different Crosslinking Agents in the Preparation of Dispersed Phase on Molecularly Imprinted Polymers

[0063] Based on the preparation method in Example 2, different cross-linking agents (see Table 3) were used to obtain different molecularly imprinted polymers, and the changes in their molding rate, size, etc. were observed. The results are shown in Table 3:

[0064] Table 3

[0065] Crosslinking agent Polymer adsorption N,N'-Methylenebisacrylamide (MBA) 60.39mg / g Polyethylene glycol dimethacrylate (EGDMA) 54.71mg / g Divinylbenzene (DVB) 30.09mg / g

[0066] It can be seen from Table 3 that different molecular imprinting polymers prepared by using N, N'-methylenebisacrylamide and polyethylene glycol dimethacrylate as cross-linking agents all have good adsorption capacity for ginsenoside Rg3, and the adsorption effect of divinylbenzene is slightly lower than that of the other two.

[0067] Experimental Example 4 Investigating the Effect of Using Different Initiators in the Polymerization Step on the Properties of Molecularly Imprinted Polymers

[0068] 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:

[0069] Table 4

[0070] Initiator Polymerization Potassium Persulfate Simple operation, quick response, stable process Benzoyl peroxide Simple operation, quick response, slightly poor process stability Ammonium Persulfate Simple operation, quick response, stable process

[0071] As shown in Table 4, different molecular imprinted polymers were prepared by using potassium persulfate, benzoyl peroxide and ammonium persulfate as initiators, all of which were simple to operate and had rapid reactions. The difference was that the molecular imprinted polymers prepared by potassium persulfate and ammonium persulfate had stable reaction processes, while the molecular imprinted polymer prepared by benzoyl peroxide had slightly less stable reaction processes.

[0072] Experimental Example 5 Investigating the Effect of Different Reaction Conditions in the Polymerization Step on the Properties of Molecularly Imprinted Polymers in the Preparation Method

[0073] Based on the preparation method in Example 2, different molecular 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), and their adsorption amounts for ginsenoside Rg3 were measured respectively. The results are shown in Table 5:

[0074] Table 5

[0075]

[0076] It can be seen from Table 5 that different molecular imprinted polymers prepared under the conditions of polymerization reaction temperature of 30-90℃ and reaction time of 1-4h can form microspheres; the molecular imprinted polymers prepared under the conditions of reaction temperature of 50℃, reaction time of 3h and reaction temperature of 70℃, reaction time of 2h have good adsorption capacity for ginsenoside Rg3. However, the molecular imprinted polymer microspheres prepared under the conditions of reaction temperature of 30℃, reaction time of 4h and reaction temperature of 90℃, reaction time of 1h have slightly lower adsorption capacity for ginsenoside Rg3.

[0077] Example 3 Testing the adsorption performance of the molecularly imprinted polymer obtained in Example 2 on various natural saponins:

[0078] The adsorption performance test of ginsenoside Rg3 was carried out according to the method described in 2.1, except that the test molecule used a substitute molecule (natural saponin compound molecule) to replace ginsenoside Rg3. The obtained data are shown in Table 6.

[0079] Table 6

[0080] serial number Chemical name CAS Number Adsorption capacity (mg / g) 1 Anemarrhena saponin AIII 41059-79-4 52.70 2 Anemarrhena saponin BII 136656-07-0 56.34 3 Anemarrhena saponin BIII 142759-74-8 49.55 4 Notoginsenoside R1 80418-24-2 52.41 5 Ginsenoside Rg1 22427-39-0 53.10 6 Ginsenoside Rh2 78214-33-2 57.27 7 Tribulus saponin K 193605-07-1 52.54 8 Tribulus saponin D 179464-23-4 57.66 9 Platycodon saponin D 58479-68-8 49.05 10 Ophiopogonin B 182284-68-0 52.39 11 Paris polyphylla saponin I 50773-41-6 52.96 12 Paris polyphylla saponin II 76296-72-5 51.75 13 Paris polyphylla saponin VI 55916-51-3 53.22

[0081] It can be seen from Table 6 that the molecular imprinting polymer prepared in Example 2 has good adsorption performance for the natural saponin compound molecules of timosaponin AIII, timosaponin BII, timosaponin BIII, notoginsenoside R1, ginsenoside Rg1, ginsenoside Rh2, tribulus terrestris saponin K, tribulus terrestris saponin D, platycodon saponin D, ophiopogonin B, paridis saponin I, paridis saponin II, and paridis saponin VI.

[0082] Example 4 Application of the molecularly imprinted polymer obtained in Test Example 2

[0083] In order to verify the separation performance and application potential of the molecular imprinted polymer, the molecular imprinted polymer was used as an adsorbent material for internal phase extraction to enrich and separate Anemarrhena saponin BII from the extract of Anemarrhena asphodeloides.

[0084] The specific experiments are as follows:

[0085] (1) Preparation of Anemarrhena extract: Weigh 0.5 g of Anemarrhena powder, add 80 mL of 60% ethanol solution, extract under ultrasonic reflux for 0.5 h, separate the supernatant after centrifugation, repeat the extraction residue 3 times, combine the supernatants, filter with a 0.1 μm membrane, take the filtrate, and concentrate it by rotary evaporator to obtain Anemarrhena extract (medicinal material: extract = 5:1, W / W), seal and keep at low temperature for later use.

[0086] (2) Adsorption experiment: First, 200 mg of molecularly imprinted polymer was loaded into a solid phase extraction column and activated with 5 mL of methanol. Then, 20 mg / mL of Anemarrhena extract loading solution was prepared with methanol, and 3 mL of loading solution was loaded; then, it was rinsed with 4 mL of methanol; and then eluted with ethanol-acetic acid (95:5, v / v).

[0087] (3) Result analysis: The collected solution was tested by HPLC according to the detection method of timosaponin BII in timosaponin medicinal materials in the Chinese Pharmacopoeia 2015 edition P213. The concentration of timosaponin BII in the solution before and after adsorption was calculated, and the recovery rate was 82.4%.

[0088] The above is only an implementation method of the 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 invention, which still fall within the scope of patent protection.

Claims

1. A template molecule of a multifunctional saponin compound molecularly imprinted polymer, 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 form solution A; Prepare the continuous phase: Mix the emulsifier and n-hexane under an inert gas atmosphere to form a continuous phase as solution B; Preparation of inverse dispersion system: Mix solution A and solution B under an inert gas atmosphere to obtain a white emulsion; Polymerization reaction: Mix the white latex with the initiator to obtain a polymer microsphere mixture; Post-treatment: Mix the polymer microsphere mixture with methanol, filter out the precipitate, wash the precipitate to neutrality after eluting the template molecules, and then dry it to constant weight to obtain molecularly imprinted polymer microspheres.

3. The molecularly imprinted polymer according to claim 2, characterized in that In preparing the dispersed phase, the hydrophilic functional monomer is one of acrylamide, allylamine and methacrylic acid.

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

5. The molecularly imprinted polymer according to claim 2, characterized in that In preparing the dispersed phase, the molar ratio of the hydrophilic functional monomer to the template molecule is 1:4.5-8.

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 and polyoxyethylene lauryl ether.

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

8. The molecularly imprinted polymer according to claim 2, characterized in that During the polymerization reaction, the polymerization temperature is 30 to 90°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 compounds are timosaponin AIII, timosaponin BII, timosaponin BIII, notoginsenoside R1, ginsenoside Rg1, ginsenoside Rg3, ginsenoside Rh2, tribulus terrestris saponin K, tribulus terrestris saponin D, platycodon saponin D, ophiopogon saponin B, paridis saponin I, paridis saponin II, and paridis saponin VI.

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