Technology for extracting ursolic acid triterpene acid in red dates

Abstract

The invention discloses an extraction technology of ursolic acid triterpene acid in red dates, and relates to the technical field of natural product extraction, and the extraction technology comprises the following steps: crushing dried red dates to 40-60 meshes, adding an acetic acid buffer solution with the pH value of 5.5 according to a solid-liquid ratio of 1: 10g / mL, sequentially adding 1000U / g beta-glucosidase, 800U / g pectin methylesterase and 1500U / g cellulase, and carrying out oscillation reaction at the constant temperature of 45 DEG C for 2.5 hours; according to the method disclosed by the invention, by virtue of bionic enzymolysis-supercritical CO2 coupled ionic liquid and a pulsed electric field-enzymolysis coupled aqueous two-phase distribution technology, association of the ionic liquid and the pulsed electric field-enzymolysis coupled aqueous two-phase distribution technology is cut off from a molecular level, so that the extraction efficiency of the ursolic acid is greatly improved; meanwhile, polysaccharide residues are effectively reduced, the product purity is improved, oxidative degradation and conformation isomerization are avoided, and the strict requirements of pharmaceutical preparations for high-purity and high-activity components are met; in addition, the method has outstanding performance in the aspect of reducing the production cost, reduces solvent consumption and energy consumption, and conforms to the green chemistry concept.

Description

Technical Field

[0001] The present invention relates to the technical field of natural product extraction, and specifically to an extraction technology for ursolic acid triterpenic acid in red dates. Background Art

[0002] In the research on the extraction of ursolic acid triterpenic acid from red dates, when polar solvents such as ethanol and methanol are used for extraction, it is observed that water-soluble polysaccharide components (such as pectin and hemicellulose) in the red date matrix are simultaneously dissolved with ursolic acid. This phenomenon results in the formation of a colloidal association between the target product and the polysaccharide during the column chromatography process in the subsequent purification process, significantly affecting the mass transfer efficiency of the separation medium, manifested as a sharp decrease in the chromatography flow rate, and the recovery rate of the target substance being lower than the theoretical expectation. Through infrared spectroscopy analysis, it is confirmed that there is an overlap of characteristic absorption peaks between the C=O group of the ursolic acid molecule and the hydroxyl group of the pectin molecule, indicating that the two form an intermolecular association structure through hydrogen bonding.

[0003] The cell wall of red dates consists of cellulose, hemicellulose, and pectin to form a three-dimensional network dense structure. As a lipophilic component, ursolic acid is mainly wrapped inside this polysaccharide network through hydrophobic interaction and hydrogen bonding. The traditional solvent extraction method can only destroy the physical structure of cells and cannot directionally cut off the intermolecular force between the polysaccharide and ursolic acid, resulting in the two existing in the extract in a co-dissolved state. In addition, the high-viscosity characteristic of the polysaccharide component significantly increases the mass transfer resistance of the target substance, further exacerbating the separation difficulty of the co-dissolved system.

[0004] The existing technology mainly uses a stepwise extraction process or a macroporous resin adsorption technology for separation: the stepwise extraction process attempts to achieve component separation by first extracting polysaccharides with water and then extracting ursolic acid with organic solvents, but this method requires long-term treatment at a relatively high temperature, resulting in the oxidation and degradation of ursolic acid; the macroporous resin adsorption technology faces problems such as insufficient selective adsorption capacity and easy blockage of resin pores by polysaccharides, and frequent regeneration operations lead to a significant increase in separation costs. The above methods do not solve the co-dissolution problem from the essential level of intermolecular interaction, but only stay in the improvement of physical separation processes and cannot break through the technical bottlenecks of mass transfer efficiency and selective separation.

[0005] In the field of pharmaceutical applications, ursolic acid triterpenic acid, as a component with biological activities such as anti-tumor and anti-inflammatory, has strict requirements for the purity of its preparations. Residual polysaccharides will not only cause stability problems in preparations such as injections, but also significantly increase the cost of subsequent purification processes. Therefore, developing an extraction technology that can directionally dissociate the polysaccharide-ursolic acid co-dissolved system is of great significance for improving the extraction efficiency of the target substance, reducing industrial production costs, and promoting the development of high-value-added preparations.

[0006] In view of this, an extraction technology for ursolic acid triterpenic acid in red dates is provided to overcome the above problems. Summary of the Invention

[0007] The object of the present invention is to provide an extraction technique for ursolic acid triterpenic acid in red dates, so as to solve the problems put forward in the above-mentioned background technology.

[0008] To solve the above technical problems, an extraction technique for ursolic acid triterpenic acid in red dates provided by the present invention includes the following steps:

[0009] Crush the dried red dates to 40-60 mesh, add acetic acid buffer solution with pH 5.5 according to the solid-liquid ratio of 1:10 g / mL, and sequentially add 1000 U / g β-glucosidase, 800 U / g pectin methylesterase and 1500 U / g cellulase, and carry out a constant temperature oscillation reaction at 45 °C for 2.5 hours;

[0010] Transfer the enzymatically hydrolyzed material to a supercritical extraction device, and use 1-butyl-3-

[0011] methylimidazolium chloride with a water content of 5% as an entrainer, accounting for 8% of the CO2 flow rate, and extract for 90 minutes under the conditions of a temperature of 38 °C, a pressure of 15 MPa, and a CO2 flow rate of 20 L / h. During the extraction process, monitor the characteristic absorption peak of ursolic acid at 1705 cm , ,

[0017] ,

[0012] , ,

[0016] ,

[0011] , , , -1 ,

[0015] ,

[0010] , , ,

[0014] ,

[0009] , ,

[0013] ,

[0008] , intensity, and terminate the extraction when the signal intensity tends to be stable;

[0012] The extraction phase is decompressed and heated to 50 °C and 0.1 MPa to release CO2, and the ionic liquid phase rich in ursolic acid is collected. Add 3 times the volume of the thermosensitive solvent N-

[0013] isopropylacrylamide aqueous solution with a concentration of 20%, stir at 60 °C for 30 minutes and then cool to 25 °C to trigger the lower critical solution temperature effect of NIPAM, so that ursolic acid precipitates in the form of nanocrystals, and the crude extract is obtained after centrifugation;

[0014] Using oleanolic acid as a template molecule, prepare a specific adsorption resin MIPs by surface molecular imprinting technology. Dissolve the crude extract in a solution with a volume ratio of methanol to water of 7:3, and pass it through the MIPs column at a flow rate of 1 mL / min. First, elute the residual polysaccharides with a 5% ethanol aqueous solution, and then elute the target substance with a solution with a volume ratio of acetonitrile to acetic acid of 9:1. Collect the eluate and freeze-dry it.

[0015] Further, the anhydrous solvent system in the supercritical extraction device is aromatic hydrocarbon, fatty alcohol or a mixture thereof, and the water content of the anhydrous solvent system is less than 100 ppm.

[0016] Further, β-glucosidase, pectin methylesterase and cellulase are screened through orthogonal experiments.

[0017] Furthermore, during the molecularly imprinted solid-phase extraction process, the specific adsorption capacity of MIPs for ursolic acid is not less than 150 mg / g.

[0018] Furthermore, the particle size of the dried and pulverized red dates is uniform, and the proportion of particles in the range of 40 to 60 mesh is not less than 90%.

[0019] Furthermore, the pH value of the thermosensitive solvent N-isopropylacrylamide (NIPAM) aqueous solution is between 6.8 and 7.2.

[0020] Furthermore, during the supercritical CO2 extraction process, the pressure fluctuation range is controlled within ±0.5 MPa, and the temperature fluctuation range is controlled within ±2°C.

[0021] Furthermore, for the specific adsorption resin MIPs prepared by surface molecular imprinting technology, its pore size distribution is between 5 and 50 nm.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. Solve the co-solubility problem and improve the extraction efficiency: Traditional extraction methods are difficult to separate ursolic acid and polysaccharides in red dates, resulting in low recovery rates of target substances. The present invention uses a bionic enzymatic hydrolysis-supercritical CO2 coupling ionic liquid technology (Example 1) and a pulsed electric field-

[0024] enzymatic hydrolysis coupling aqueous two-phase partitioning technology (Example 2) to cut off the association between ursolic acid and polysaccharides at the molecular level. For example, in Example 1, a composite enzyme system is used to directionally degrade the polysaccharide network, increasing the exposure rate of ursolic acid, and supercritical CO2 and ionic liquid are used synergistically for extraction to avoid the formation of co-solubility complexes; in Example 2, pulsed electric fields are used to enhance mass transfer, combined with enzymatic hydrolysis and aqueous two-phase partitioning for in-situ separation, greatly improving the extraction efficiency of ursolic acid and solving the problem of difficult separation of co-solutes.

[0025] 2. Improve the product purity and meet the pharmaceutical requirements: The pharmaceutical field has strict requirements for the purity of ursolic acid, and polysaccharide residues will affect the stability of preparations. While improving the extraction rate, the present invention significantly improves the purity of ursolic acid. After purification by molecularly imprinted solid-phase extraction in Example 1, it can effectively exclude the interference of structural analogs such as oleanolic acid, and the purity of ursolic acid after purification can reach an extremely high level; through a series of processes in Example 2, the obtained ursolic acid crystals have high purity and avoid oxidation degradation and conformational isomerization caused by high temperature, meeting the requirements of pharmaceutical-grade preparations for high-purity and high-activity ingredients.

[0026] 3. Reduce production costs and achieve green environmental protection: Existing technologies suffer from high costs and severe pollution. The present invention reduces costs in multiple aspects. In Example 1, the temperature-sensitive solvent is used to recover ursolic acid, and the ionic liquid has a high recovery rate, reducing solvent consumption costs. In Example 2, the pulsed electric field pretreatment has low energy consumption, and the vacuum membrane distillation concentration energy consumption is also significantly reduced, reducing energy consumption. At the same time, it avoids the complex processing steps and high pollution problems of traditional processes, conforming to the concept of green chemistry.

[0027] 4. Adapting to different needs and expanding application scenarios: The present invention provides two different implementation methods with different application scenarios. Example 1 focuses on the precise control of intermolecular forces and is suitable for high-purity extraction in the laboratory, meeting the needs of fields such as pharmaceutical research and development that have extremely high requirements for product purity. Example 2 focuses on process integration and efficiency improvement, which can shorten extraction time and reduce energy consumption. It is suitable for industrial continuous production, meets the needs of large-scale production, and expands the application scope of this extraction technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the principle of the extraction technology of ursolic acid and triterpenoid acid in red dates according to the present invention. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] See also Figure 1 , the present invention provides a technical solution:

[0031] See Figure 1 As shown, an embodiment of a technology for extracting ursolic acid and triterpenoid acid from red dates:

[0032] Example 1: Synergistic dissociation and extraction process based on biomimetic enzymatic hydrolysis-supercritical CO2 coupled ionic liquid:

[0033] The specific steps are as follows:

[0034] Red date raw material pretreatment and enzymatic hydrolysis system construction: the dried red dates were crushed into 40-60 mesh, and pH 5.5 acetate buffer was added at a material-liquid ratio of 1:10 (g / mL), and β-

[0035] Glucosidase (1000 U / g raw material), pectin methylesterase (800 U / g raw material) and cellulase (1500 U / g raw material) were reacted at 45° C. with shaking for 2.5 hours.

[0036] Supercritical CO2-

[0037] Ionic liquid biphasic extraction: Transfer the enzymatically hydrolyzed material into a supercritical extraction device, using 1-butyl-3-

[0038] methylimidazolium chloride ([BMIM]Cl) with a water content of 5% as an entrainer (accounting for 8% of the CO2 flow rate), and extract for 90 minutes under the conditions of a temperature of 38 °C, a pressure of 15 MPa, and a CO2 flow rate of 20 L / h. During the extraction process, monitor the intensity of the characteristic absorption peak (1705 cm -1 ) of ursolic acid by on-line infrared spectroscopy, and terminate the extraction when the signal intensity tends to be stable.

[0039] Thermosensitive solvent recovery and target enrichment: Release CO2 from the extraction phase by reducing pressure and raising the temperature (50 °C, 0.1 MPa), and collect the ionic liquid phase rich in ursolic acid. Add 3 times the volume of the thermosensitive solvent N-

[0040] isopropylacrylamide (NIPAM) aqueous solution (concentration 20%, pH 7.0) to the ionic liquid phase, stir at 60 °C for 30 minutes and then cool to 25 °C to trigger the lower critical solution temperature (LCST) effect of NIPAM, so that ursolic acid precipitates in the form of nanocrystals, and the crude extract is obtained after centrifugation.

[0041] Molecularly imprinted solid-phase extraction refinement: Using ursolic acid as a template molecule, prepare a specific adsorption resin (MIPs) by surface molecular imprinting technology. Dissolve the crude extract in a methanol-

[0042] water (volume ratio 7:3) solution, pass it through the MIPs column at a flow rate of 1 mL / min, first elute the residual polysaccharides with a 5% ethanol aqueous solution, and then elute the target with an acetonitrile-acetic acid (volume ratio 9:1) solution, collect the eluate and freeze-dry it.

[0043] Molecular dissociation and exposure rate improvement: The composite enzyme system (β-

[0044] glucosidase, pectin methylesterase, cellulase) screened by orthogonal experiments can orientedly degrade the cellulose skeleton and pectin binding structure in the jujube cell wall, and destroy the hydrogen bond association network between ursolic acid and polysaccharides. During the enzymatic hydrolysis process, pectin methylesterase preferentially cuts the methyl ester bond in pectin molecules to reduce the viscosity of polysaccharides; cellulase further hydrolyzes the cell wall microfibrils, increasing the exposure rate of ursolic acid from 40%-50% in traditional extraction to 75%-80%, creating molecular dissociation conditions for subsequent extraction.

[0045] Efficient extraction and impurity separation: In the low-polarity environment (dielectric constant ε = 1.09) of supercritical CO2, ursolic acid is selectively dissolved, while the imidazole cation of ionic liquid [BMIM]Cl forms hydrogen bond competition binding with the hydroxyl groups of pectin, cutting off the intermolecular force between ursolic acid and polysaccharides. Compared with traditional solvent extraction, this biphasic system increases the extraction rate of ursolic acid to over 92%, and reduces the dissolution amount of polysaccharides by 60%, avoiding the formation of co-dissolved complexes from the source. The introduction of ionic liquid breaks through the limitation of supercritical CO2 on the dissolution ability of polar molecules, achieving efficient separation of non-polar target substances and polar impurities.

[0046] Low-temperature separation and purity improvement: Utilize the thermosensitive property of NIPAM to achieve efficient separation of ionic liquid and ursolic acid, avoiding the thermal damage to ursolic acid by traditional distillation method (the oxidation degradation rate is reduced from 15% of the traditional method to below 3%). This step improves the purity of the crude extract of ursolic acid from 50%-60% of the conventional method to 85%-90%, and the recovery rate of ionic liquid reaches over 95%, significantly reducing the solvent consumption cost.

[0047] Precise separation and high-purity preparation: The specific adsorption capacity of MIPs for ursolic acid reaches 150 mg / g, nearly doubling that of traditional macroporous resins (50 - 80 mg / g), and can effectively exclude the interference of structural analogues such as oleanolic acid (separation factor α = 2.8). The purity of refined ursolic acid can reach over 98.5%, solving the separation problem caused by structural similarity in the existing technology and meeting the high-purity requirements of pharmaceutical-grade preparations.

[0048] Example 2: Low-energy dissociation process based on pulsed electric field -

[0049] enzymolysis coupling (suitable for industrial continuous production):

[0050] The specific steps are as follows:

[0051] Pulsed electric field pretreatment: Pass the jujube homogenate into the pulsed electric field device with a 3 cm gap, apply a bidirectional pulse with a field strength of 25 kV / cm, a pulse width of 10 μs, and a frequency of 500 Hz, and the treatment time is 30 seconds. After treatment, the conductivity of the material increases by 40%, indicating a significant enhancement in cell wall permeability.

[0052] Gradient enzymolysis and aqueous two-phase partitioning: Add a composite enzyme (cellulase:pectinase = 2:1, total enzyme amount 1.5% w / w) to the material after pulsed treatment, enzymolyze at 50 °C for 1.5 hours, and then add PEG4000 -

[0053] ammonium sulfate aqueous two-phase system (PEG concentration 15%, ammonium sulfate concentration 20%), stir at high speed for 5 minutes and then let it stand for phase separation. Ursolic acid is enriched in the upper PEG phase (partition coefficient K = 3.5), while polysaccharides mainly exist in the lower-phase salt solution.

[0054] Vacuum membrane distillation concentration and crystallization: Collect the PEG-phase solution, and perform vacuum membrane distillation using a hydrophobic polypropylene hollow fiber membrane (pore size 0.2 μm) (operating temperature 40°C, vacuum degree 80 kPa) to concentrate the solution volume to 1 / 10 of the original volume. The concentrated solution is cooled and crystallized (left standing at 5°C for 12 hours), and ursolic acid crystals (purity above 92%) are obtained after centrifugation.

[0055] Physical cell wall breaking and mass transfer optimization: Pulse electric fields form nanoscale irreversible pores (pore size 50 -

[0056] 100 nm) on the cell wall, shortening the intracellular diffusion path of ursolic acid by more than 60% and reducing the mass transfer resistance by 3 times compared with traditional ultrasonic treatment. This pretreatment step does not require chemical reagents, and the energy consumption is only 40% of that of ultrasonic extraction, breaking the encapsulation of ursolic acid by the polysaccharide network from a physical level.

[0057] Synergistic separation and process simplification: Gradient enzymatic hydrolysis combined with aqueous two-phase partitioning forms a "hydrolysis -

[0058] partitioning" synergistic effect: Enzymatic hydrolysis destroys the polysaccharide network to release ursolic acid, and the aqueous two-phase system uses the hydrophobicity difference between the target substance and polysaccharide to achieve in-situ separation. This step omits the solid-liquid separation link in the traditional process, shortens the extraction time to 2 hours, and the phase transfer rate of ursolic acid reaches more than 90%, avoiding the formation of co-solvents from the process design.

[0059] Low-temperature concentration and quality assurance: Vacuum membrane distillation achieves efficient concentration at low temperature, avoiding the conformational isomerization of ursolic acid at high temperature (the retention rate of the α form reaches more than 98%). Compared with traditional evaporation concentration, this technology reduces energy consumption by 50%, and the membrane fouling rate decreases significantly (membrane flux decay rate < 10% / batch), suitable for industrial continuous production.

[0060] Example 3: Influence of changing the enzymatic hydrolysis temperature on the effect of Example 1:

[0061] The specific steps are as follows:

[0062] Red date raw material pretreatment and enzymatic hydrolysis system construction: The same as Example 1, only adjust the enzymatic hydrolysis temperature to 35°C, keep other conditions unchanged, and perform a constant-temperature oscillation reaction at 35°C for 2.5 hours.

[0063] Supercritical CO2 - ionic liquid biphasic extraction: The same as Example 1.

[0064] Thermosensitive solvent recovery and target substance enrichment: The same as Example 1.

[0065] Molecularly imprinted solid-phase extraction purification: The same as Example 1.

[0066] Considerations for selecting parameters to change:

[0067] The enzymatic hydrolysis temperature has a significant impact on the activity of the enzyme. Selecting 35°C is to explore the degradation effect of the complex enzyme system on the jujube cell wall and its impact on the subsequent extraction of ursolic acid under the condition of a lower enzymatic hydrolysis temperature than that in Example 1. A lower temperature may reduce the activity of the enzyme, thereby affecting the exposure rate and extraction rate of ursolic acid. By comparison, the rationality and advantages of the enzymatic hydrolysis temperature in Example 1 can be clarified.

[0068] Results and comparison:

[0069] The exposure rate of ursolic acid is 65%-70%, lower than 75%-80% in Example 1. The extraction rate is 85%, lower than over 92% in Example 1. This indicates that the enzymatic hydrolysis temperature of 45°C in Example 1 is more conducive to the complex enzyme system to play its role and improve the exposure rate and extraction rate of ursolic acid.

[0070] Example 4: Influence of changing the proportion of ionic liquid entrainer on the effect of Example 1:

[0071] The specific steps are as follows:

[0072] Pretreatment of jujube raw materials and construction of the enzymatic hydrolysis system: The same as in Example 1.

[0073] Supercritical CO2-

[0074] Ionic liquid biphasic extraction: Adjust the proportion of [BMIM]Cl entrainer in the CO2 flow rate to 5%, and the other conditions are the same as in Example 1 for extraction.

[0075] Recovery of temperature-sensitive solvent and enrichment of target substance: The same as in Example 1.

[0076] Molecular imprinted solid-phase extraction and refinement: The same as in Example 1.

[0077] Considerations for selecting parameters to change:

[0078] The proportion of the ionic liquid entrainer will affect its hydrogen bond competition binding ability with the hydroxyl groups of pectin and the dissolution effect of supercritical CO2 on ursolic acid. Selecting a proportion of 5% is to compare whether the intermolecular force between ursolic acid and polysaccharide can be effectively cut off and its impact on the extraction rate and the polysaccharide dissolution amount under a lower entrainer proportion, so as to verify the optimality of the entrainer proportion in Example 1.

[0079] Results and comparison:

[0080] The extraction rate of ursolic acid is 88%, and the polysaccharide dissolution amount is reduced by 50%. Compared with Example 1, the extraction rate decreases, and the reduction amplitude of the polysaccharide dissolution amount also becomes smaller, indicating that the entrainer proportion of 8% in Example 1 can better achieve the separation of ursolic acid and polysaccharide and improve the extraction effect.

[0081] Example 5: Influence of changing the concentration of the temperature-sensitive solvent on the effect of Example 1:

[0082] The specific steps are as follows:

[0083] Pretreatment of red date raw materials and construction of enzymatic hydrolysis system: The same as in Example 1.

[0084] Supercritical CO2 - ionic liquid biphasic extraction: The same as in Example 1.

[0085] Recovery of thermosensitive solvent and enrichment of target substance: Adjust the concentration of NIPAM aqueous solution to 15%, and perform the operation under the same conditions as in Example 1.

[0086] Molecularly imprinted solid - phase extraction purification: The same as in Example 1.

[0087] Considerations for choosing to change parameters:

[0088] The concentration of the thermosensitive solvent NIPAM affects the precipitation effect of ursolic acid when triggering the LCST effect. Selecting a concentration of 15% is to explore whether the separation of ionic liquid and ursolic acid can be effectively achieved at a lower concentration, as well as the impact on the purity of the crude extract and the recovery rate of the ionic liquid, thereby highlighting the rationality of the NIPAM concentration in Example 1.

[0089] Results and comparison:

[0090] The purity of the crude ursolic acid extract is 80% - 85%, lower than 85% - 90% in Example 1, and the recovery rate of the ionic liquid is 90%, also lower than over 95% in Example 1. This shows that a 20% NIPAM aqueous solution concentration in Example 1 is more conducive to the enrichment of ursolic acid and the recovery of the ionic liquid, improving the purity of the crude extract.

[0091] Example 6: Influence of changing the pulsed - electric - field intensity on the effect of Example 2:

[0092] The specific steps are as follows:

[0093] Pulsed - electric - field pretreatment: Adjust the pulsed - electric - field intensity to 20 kV / cm, and treat the red - date homogenate under the same conditions as in Example 2.

[0094] Gradient enzymatic hydrolysis and aqueous two - phase partitioning: The same as in Example 2.

[0095] Vacuum membrane distillation concentration and crystallization: The same as in Example 2.

[0096] Considerations for choosing to change parameters:

[0097] The pulsed - electric - field intensity determines the cell - wall breaking effect on red dates and the degree of mass - transfer enhancement. Selecting 20 kV / cm is to study whether the polysaccharide network's encapsulation of ursolic acid can be effectively broken at a lower field intensity, as well as the impact on subsequent extraction efficiency and the phase - transfer rate of ursolic acid, so as to verify the effectiveness of the field - intensity setting in Example 2.

[0098] Results and comparison:

[0099] The conductivity of the treated material increased by 30%, the intracellular diffusion path of ursolic acid was shortened by 50%, and the mass transfer resistance was reduced by 2 times compared with traditional ultrasonic treatment. The extraction time was extended to 2.5 hours, and the phase transfer rate of ursolic acid was 85%. Compared with Example 2, all indicators were inferior to those in Example 2, indicating that the electric field strength of 25 kV / cm in Example 2 was more conducive to improving the extraction efficiency and the phase transfer rate of ursolic acid.

[0100] Example 7: Effect of changing the PEG concentration in the aqueous two-phase system on the effect of Example 2:

[0101] The specific steps are as follows:

[0102] Pulsed electric field pretreatment: The same as in Example 2.

[0103] Gradient enzymatic hydrolysis and aqueous two-phase partitioning: Adjust the PEG4000 concentration to 10%, and adjust the ammonium sulfate concentration to the value that maintains the system balance accordingly. The remaining conditions are the same as in Example 2, and the operation is carried out.

[0104] Vacuum membrane distillation concentration and crystallization: The same as in Example 2.

[0105] Considerations for selecting parameters to change:

[0106] The PEG concentration in the aqueous two-phase system affects the hydrophobic difference and distribution coefficient between the target substance and polysaccharides. Selecting a PEG concentration of 10% is to explore the separation effect of the aqueous two-phase system on ursolic acid and polysaccharides, as well as the influence on the extraction time and the phase transfer rate of ursolic acid under a lower PEG concentration, so as to highlight the rationality of the PEG concentration in Example 2.

[0107] Results and comparison:

[0108] The distribution coefficient K of ursolic acid enriched in the upper PEG phase is 3.0, the extraction time is extended to 2.2 hours, and the phase transfer rate of ursolic acid is 88%. Compared with Example 2, the distribution coefficient decreases, the extraction time extends, and the phase transfer rate drops, indicating that the PEG concentration of 15% in Example 2 is more conducive to the efficient separation and rapid extraction of ursolic acid and polysaccharides.

[0109] Example 8: Effect of changing the vacuum membrane distillation temperature on the effect of Example 2:

[0110] The specific steps are as follows:

[0111] Pulsed electric field pretreatment: The same as in Example 2.

[0112] Gradient enzymatic hydrolysis and aqueous two-phase partitioning: The same as in Example 2.

[0113] Vacuum membrane distillation concentration and crystallization: Adjust the operating temperature of vacuum membrane distillation to 45°C, and keep the other conditions the same as in Example 2, then conduct the concentration and crystallization operations.

[0114] Vacuum membrane distillation concentration and crystallization: The same as in Example 2.

[0115] Considerations for parameter selection:

[0116] The temperature of vacuum membrane distillation affects the concentration efficiency and the stability of ursolic acid. Selecting 45°C is to study the influence on the conformational isomerization of ursolic acid, as well as the influence on the concentration efficiency and the membrane fouling rate at a temperature slightly higher than that in Example 2, so as to verify the scientificity of the temperature setting in Example 2.

[0117] Results and comparison:

[0118] The retention rate of the α-form of ursolic acid is 95%, which is lower than more than 98% in Example 2, and the membrane flux decay rate is 12% / batch, which is higher than 10% / batch in Example 2. This shows that the vacuum membrane distillation temperature of 40°C in Example 2 is more conducive to maintaining the conformational stability of ursolic acid and reducing the membrane fouling rate.

[0119] Example 9: Comparison of the effect of single enzymatic hydrolysis with that of Example 1:

[0120] The specific steps are as follows:

[0121] Pretreatment of red date raw materials and construction of enzymatic hydrolysis system: Only add cellulase (1500 U / g raw materials), without adding β-

[0122] glucosidase and pectin methyl esterase, add acetic acid buffer solution with pH of 5.5 according to the solid-liquid ratio of 1:10 (g / mL), and carry out constant temperature oscillation reaction at 45°C for 2.5 hours.

[0123] Supercritical CO2-ionic liquid biphasic extraction: The same as in Example 1.

[0124] Recovery of thermosensitive solvent and enrichment of target substances: The same as in Example 1.

[0125] Molecular imprinting solid phase extraction purification: The same as in Example 1.

[0126] Considerations for parameter selection:

[0127] Using single enzymatic hydrolysis can compare the synergistic effect of each enzyme in the complex enzyme system. Selecting only cellulase is because cellulase plays an important role in degrading the cell wall structure. By comparing the effects of single cellulase hydrolysis and complex enzymatic hydrolysis, the contribution of other enzymes in destroying the association network between ursolic acid and polysaccharides can be clarified, highlighting the advantages of the complex enzyme system in Example 1.

[0128] Results and comparison:

[0129] The exposure rate of ursolic acid is 50%-55%, far lower than 75%-80% in Example 1. The extraction rate is 70%, significantly lower than over 92% in Example 1. It shows that the synergistic effect of β-glucosidase and pectin methylesterase with cellulase in the complex enzyme system is crucial for improving the exposure rate and extraction rate of ursolic acid, and the complex enzymatic hydrolysis system in Example 1 is superior.

[0130] The synergistic effect of β-glucosidase and pectin methylesterase with cellulase in the complex enzyme system is crucial for improving the exposure rate and extraction rate of ursolic acid, and the complex enzymatic hydrolysis system in Example 1 is superior.

[0131] Example 10: Effect of changing the supercritical CO2 extraction time on the effect of Example 1:

[0132] The specific steps are as follows:

[0133] Pretreatment of red date raw materials and construction of enzymatic hydrolysis system: The same as Example 1.

[0134] Supercritical CO2-ionic liquid biphasic extraction: Adjust the supercritical CO2 extraction time to 60 minutes, and the other conditions are the same as Example 1.

[0135] Recovery of thermosensitive solvent and enrichment of target substance: The same as Example 1.

[0136] Purification by molecularly imprinted solid-phase extraction: The same as Example 1.

[0137] Considerations for choosing to change parameters:

[0138] The supercritical CO2 extraction time affects the dissolution and extraction effect of ursolic acid. Shortening the extraction time to 60 minutes can explore whether ursolic acid can be fully extracted within a shorter time and its impact on the extraction rate and the polysaccharide dissolution amount, so as to verify the rationality of the 90-minute extraction time in Example 1.

[0139] Results and comparison:

[0140] The extraction rate of ursolic acid is 80%, lower than over 92% in Example 1, and the polysaccharide dissolution amount is reduced by 55%, also lower than the effect of reducing by 60% in Example 1. It shows that the 90-minute extraction time in Example 1 can extract ursolic acid more fully and achieve a better separation effect.

[0141] Example 11: Effect of changing the pulsed electric field frequency on the effect of Example 2:

[0142] The specific steps are as follows:

[0143] Pulsed electric field pretreatment: Adjust the pulsed electric field frequency to 400 Hz, and the other conditions are the same as Example 2, and treat the red date homogenate.

[0144] Gradient enzymatic hydrolysis and aqueous two-phase partitioning: The same as Example 2.

[0145] Vacuum membrane distillation concentration and crystallization: The same as Example 2.

[0146] Considerations for parameter selection and change:

[0147] The pulsed electric field frequency affects the cell wall breaking efficiency and mass transfer effect. The frequency of 400 Hz is selected to study the influence on the permeability of red date cell walls at a lower frequency, as well as the influence on the subsequent extraction efficiency and the phase transfer rate of ursolic acid, so as to verify the correctness of the frequency setting in Example 2.

[0148] Results and comparison:

[0149] The conductivity of the treated material increases by 35%, the intracellular diffusion path of ursolic acid is shortened by 55%, and the mass transfer resistance is reduced by 2.5 times compared with traditional ultrasonic treatment. The extraction time is extended to 2.3 hours, and the phase transfer rate of ursolic acid is 87%. Compared with Example 2, all key indicators decline, indicating that the frequency of 500 Hz in Example 2 is more conducive to improving the extraction efficiency and the phase transfer rate of ursolic acid, thus verifying the rationality and advantages of the frequency parameter in Example 2.

[0150] Example 12: Influence of changing the enzymatic hydrolysis time on the effect of Example 2:

[0151] The specific steps are as follows:

[0152] Pulsed electric field pretreatment: The same as in Example 2.

[0153] Gradient enzymatic hydrolysis and aqueous two-phase partitioning: Adjust the enzymatic hydrolysis time to 1 hour, and the composite enzyme (cellulase: pectinase = 2:1, total enzyme amount 1.5% w / w) and other conditions are the same as in Example 2.

[0154] Vacuum membrane distillation concentration and crystallization: The same as in Example 2.

[0155] Considerations for parameter selection and change:

[0156] The enzymatic hydrolysis time affects the degree of damage of the composite enzyme to the polysaccharide network, and thus affects the release amount of ursolic acid. Selecting an enzymatic hydrolysis time of 1 hour aims to explore whether the polysaccharide network can be fully damaged under a shorter enzymatic hydrolysis time, as well as the influence on the subsequent extraction efficiency and purity of ursolic acid, so as to evaluate the necessity of the 1.5-hour enzymatic hydrolysis time in Example 2.

[0157] Results and comparison:

[0158] The phase transfer rate of ursolic acid drops to 82%, and the purity of ursolic acid obtained after extraction is 88%, which is lower than over 92% in Example 2. This shows that the 1.5-hour enzymatic hydrolysis time in Example 2 can better damage the polysaccharide network, achieve the efficient release and high-purity extraction of ursolic acid, and prove the scientific nature of the enzymatic hydrolysis time setting in Example 2.

[0159] Example 13: Influence of changing the proportion of the eluent in molecularly imprinted solid-phase extraction on the effect of Example 1

[0160] The specific steps are as follows:

[0161] Pretreatment of red date raw materials and construction of enzymatic hydrolysis system: The same as Example 1.

[0162] Supercritical CO2-ionic liquid biphasic extraction: The same as Example 1.

[0163] Recovery of temperature-sensitive solvent and enrichment of target substances: The same as Example 1.

[0164] Purification by molecularly imprinted solid-phase extraction: Adjust the 5% ethanol aqueous solution for eluting residual polysaccharides to a 3% ethanol aqueous solution; adjust the acetonitrile-acetic acid (volume ratio 9:1) solution for eluting target substances to an acetonitrile-acetic acid (volume ratio 8:1) solution, and the remaining operations are the same as in Example 1.

[0165] Considerations for selecting and changing parameters:

[0166] The ratio of the eluent will affect the elution effect of polysaccharides and the elution purity of ursolic acid. Changing the concentration of the ethanol aqueous solution and the ratio of acetonitrile-

[0167] acetic acid is to explore the influence of different eluent compositions on the separation effect, clarify the rationality of the eluent ratio in Example 1, and ensure the effective removal of impurities and the high-purity recovery of ursolic acid.

[0168] Results and comparison:

[0169] The purity of ursolic acid after purification is 95%, which is lower than over 98.5% in Example 1, and the loss rate of ursolic acid increases during the elution process. This shows that the eluent ratio set in Example 1 is more conducive to removing residual polysaccharides, improving the purification purity of ursolic acid, and reducing the loss of target substances.

[0170] Example 14: Influence of changing the ammonium sulfate concentration in the aqueous two-phase system on the effect of Example 2:

[0171] The specific steps are as follows:

[0172] Pulsed electric field pretreatment: The same as Example 2.

[0173] Gradient enzymatic hydrolysis and aqueous two-phase partitioning: Adjust the ammonium sulfate concentration to 15%, and the PEG4000 concentration remains 15%, and the remaining conditions are the same as in Example 2.

[0174] Vacuum membrane distillation concentration and crystallization: The same as Example 2.

[0175] Considerations for selecting and changing parameters:

[0176] The ammonium sulfate concentration is one of the key parameters of the aqueous two-phase system, which affects the phase equilibrium of the system and the distribution coefficient of the target substance. A 15% ammonium sulfate concentration was selected to study the changes in the separation effect of ursolic acid and polysaccharides in the aqueous two-phase system at a lower ammonium sulfate concentration, and to verify the optimality of the ammonium sulfate concentration setting in Example 2.

[0177] Results and comparison:

[0178] The distribution coefficient K of ursolic acid in the upper PEG phase decreased to 3.2, and the phase transfer rate was 86%, which was lower than 3.5 and over 90% in Example 2. This indicates that the 20% ammonium sulfate concentration in Example 2 is more conducive to the enrichment and separation of ursolic acid in the aqueous two-phase system, ensuring a higher phase transfer rate.

[0179] Example 15: Effect of changing the addition multiple of the thermosensitive solvent NIPAM on the effect of Example 1:

[0180] The specific steps are as follows:

[0181] Pretreatment of red date raw materials and construction of the enzymatic hydrolysis system: The same as in Example 1.

[0182] Supercritical CO2-ionic liquid biphasic extraction: The same as in Example 1.

[0183] Recovery of the thermosensitive solvent and enrichment of the target substance: Add an aqueous solution of 2 volumes of N-

[0184] isopropylacrylamide (NIPAM) (concentration 20%, pH 7.0) to the ionic liquid phase, and the other conditions are the same as in Example 1.

[0185] Molecularly imprinted solid-phase extraction and refinement: The same as in Example 1.

[0186] Considerations for selecting parameters to change:

[0187] The addition multiple of NIPAM affects its interaction with ursolic acid in the ionic liquid and the precipitation effect of ursolic acid. A 2-fold volume was selected to compare with the 3-fold volume in Example 1, and to explore the effects of different addition multiples on the purity of the crude ursolic acid extract and the recovery rate of the ionic liquid, so as to determine the rationality of the NIPAM addition multiple in Example 1.

[0188] Results and comparison:

[0189] The purity of the crude ursolic acid extract was 82%-87%, which was lower than 85%-90% in Example 1, and the recovery rate of the ionic liquid was 92%, which was lower than over 95% in Example 1. This shows that adding 3 volumes of NIPAM aqueous solution in Example 1 is more conducive to the enrichment of ursolic acid and the recovery of the ionic liquid, and improves the purity of the crude extract.

[0190] Summary:

[0191] Through the comparative study of multiple embodiments, it is possible to deeply and comprehensively understand the significant technical advantages of Embodiment 1 and Embodiment 2. Both Embodiment 1 and Embodiment 2 focus on the research of "the synergistic dissociation problem of the polysaccharide-ursolic acid co-dissolution system". Although different technical paths are adopted (biomimetic enzymolysis-supercritical CO2 coupling ionic liquid and pulsed electric field-enzymolysis coupling aqueous two-phase partitioning), the goals are the same, and both are committed to solving the same technical problem.

[0192] I. Core problem solved jointly: The problem of co-dissolution and dissociation of polysaccharide and ursolic acid:

[0193] In red dates, ursolic acid and polysaccharides (such as pectin and hemicellulose) form a stable co-dissolution system based on hydrogen bonds and hydrophobic interactions. Ursolic acid is wrapped inside the polysaccharide network. Traditional extraction methods only rely on physical means, such as simple solvent extraction or filtration, and cannot accurately cut off the intermolecular forces between the two, resulting in the difficult and efficient separation of the co-dissolved substances. This is the key contradiction that the technology field has faced for a long time.

[0194] Both Embodiment 1 and Embodiment 2 start from solving this contradiction, and are committed to cutting off the association between ursolic acid and polysaccharides at the molecular level to achieve the efficient separation of the target substance and impurities. Their common goal is to increase the exposure rate of ursolic acid, reduce the polysaccharide dissolution amount, improve the extraction efficiency and product purity, and avoid the interference of co-dissolved substances on subsequent purification.

[0195] II. Technical path differences and synergy between Embodiment 1 and Embodiment 2:

[0196] The two embodiments adopt significantly different and complementary technical means for the same technical problem.

[0197] Embodiment 1: Biomimetic enzymolysis and supercritical-ionic liquid coupling:

[0198] Core means: Embodiment 1 uses a composite enzyme system screened by orthogonal experiments, including β-

[0199] glucosidase, pectin methylesterase and cellulase. These enzymes specifically act on the polysaccharide components of the red date cell wall. Pectin methylesterase cuts off the methyl ester bond of pectin molecules to reduce the viscosity of polysaccharides, and cellulase hydrolyzes the microfibrils of the cell wall to destroy the encapsulation structure of ursolic acid, significantly increasing the exposure rate of ursolic acid. In supercritical CO2-

[0200] In the ionic liquid biphasic extraction stage, supercritical CO2 selectively dissolves ursolic acid due to its low-polarity environment (dielectric constant ε = 1.09). The imidazole cation of the ionic liquid [BMIM]Cl competes with the hydroxyl groups of pectin to form hydrogen bonds, breaking the hydrogen bonds between ursolic acid and polysaccharides and achieving efficient dissociation. Utilizing the lower critical solution temperature (LCST) effect of the thermosensitive solvent NIPAM, efficient separation of the ionic liquid and ursolic acid is achieved at low temperatures, avoiding thermal damage caused by traditional distillation methods and ensuring the stability of ursolic acid.

[0201] Applicable scenarios: This technical path focuses on the precise regulation of intermolecular forces and is applicable to high-purity extraction in laboratories. It can achieve a purity of ursolic acid after refinement of over 98.5%, meeting the requirements of fields with extremely high product purity such as pharmaceutical research and development.

[0202] Example 2: Coupling of pulsed electric field and aqueous two-phase partitioning:

[0203] Core means: Example 2 uses pulsed electric fields to form nanoscale irreversible pores of 50 - 100 nm on the cell wall, enhancing mass transfer efficiency. Without the use of chemical reagents, it physically breaks the encapsulation of ursolic acid by polysaccharides from the physical level, shortens the intracellular diffusion path of ursolic acid, and reduces mass transfer resistance. Through gradient enzymolysis combined with an aqueous two-phase system (PEG-

[0204] ammonium sulfate), enzymolysis destroys the polysaccharide network to release ursolic acid, and the aqueous two-phase system achieves in-situ partitioning separation based on the hydrophobicity difference between the target substance and polysaccharides, simplifying the separation process. The vacuum membrane distillation low-temperature concentration technology is used for efficient concentration in a low-temperature environment, avoiding conformational isomerization of ursolic acid at high temperatures and ensuring product quality.

[0205] Applicable scenarios: This technical path focuses on process integration and efficiency improvement. It can shorten the extraction time by 50% and reduce energy consumption by 60%, making it suitable for industrial continuous production and meeting large-scale production requirements.

[0206] III. Different embodiments of the same invention:

[0207] Example 1 and Example 2 belong to different embodiments under the same inventive concept. Both revolve around the core technical solution of "dissociating the co-dissolution system" and achieve the same technical effect of solving the problem of the co-dissolution of ursolic acid and polysaccharides through different technical combinations;

[0208] Synergistic technical effects: The two examples show excellent synergistic effects in key technical indicators. They both significantly increase the extraction rate of ursolic acid to be greater than 92%; significantly reduce the polysaccharide residue content by 60% - 70%; and improve the product purity, with the crude extract purity reaching 85% - 90%. These effects effectively solve the co-dissolution problem from different dimensions and fully demonstrate the effectiveness of the two technical solutions.

[0209] IV. Specific advantages of Example 1 and Example 2 in solving the core problems:

[0210] Dissociation mechanism that breaks through the essence of intermolecular interactions: The biomimetic enzymatic hydrolysis and supercritical CO2-ionic liquid coupling technology in Example 1, and the pulsed electric field-

[0211] enzymatic hydrolysis coupled with aqueous two-phase partitioning technology in Example 2 break through the limitations of traditional physical separation only. In Example 1, the composite enzyme system accurately degrades the polysaccharide network, combined with the competitive hydrogen bond binding of ionic liquids, to cut off the association between ursolic acid and polysaccharides at the molecular level; in Example 2, pulsed electric fields are used for physical cell wall breaking, and the separation is achieved by using the hydrophobicity difference of the aqueous two-phase system. In other comparative examples, after changing parameters such as the enzymatic hydrolysis temperature and the proportion of ionic liquid entrainer, the extraction rate and purity of ursolic acid are affected to varying degrees, proving the scientific nature of the technical solutions in Example 1 and Example 2.

[0212] Significantly improve separation efficiency and product quality: Compared with other comparative examples, Example 1 and Example 2 perform better in terms of the extraction rate of ursolic acid, the purity of the crude extract, the purity after refining, and the control of polysaccharide residue. The extraction rate in Example 1 can reach more than 92%, and the purity after refining is ≥98.5%; the extraction time in Example 2 is shortened to 2 hours, the purity reaches more than 92%, and the polysaccharide residue in both cases is reduced by more than 70%. At the same time, oxidative degradation caused by high temperature (degradation rate < 3%) and conformational isomerization (α-type retention rate > 98%) are effectively avoided, meeting the strict requirements of pharmaceutical preparations for high-purity and high-activity ingredients. For example, in comparative examples where parameters such as the concentration of thermosensitive solvents and the concentration of PEG in the aqueous two-phase system are changed, the product quality and extraction efficiency are not as good as those in Example 1 and Example 2, highlighting the advantages of these two examples.

[0213] Synergistic effect: In Example 1, the composite enzymatic hydrolysis, supercritical extraction, application of ionic liquids, and separation with thermosensitive solvents act synergistically; in Example 2, pulsed electric field pretreatment, gradient enzymatic hydrolysis, aqueous two-phase partitioning, and vacuum membrane distillation for concentration and crystallization cooperate with each other. The combination of these technical means forms an efficient extraction process. Example 1 is suitable for high-purity extraction in the laboratory, and Example 2 is suitable for industrial continuous production, showing advantages in their respective applicable scenarios, breaking through the limitations of the traditional "extraction-

[0214] purification" linear process, and achieving efficiency improvement. For example, in comparative examples where parameters such as the pulsed electric field strength and enzymatic hydrolysis time are changed, the extraction efficiency and product quality decline, indicating that the synergistic effect of the technical means in Example 1 and Example 2 is the key to achieving efficient extraction.

[0215] Those skilled in the art are familiar with the problem of the co - solubility of polysaccharides and triterpenic acids. However, traditional ideas are mostly limited to solvent screening or resin adsorption improvement. In Examples 1 and 2, the introduction of ionic liquids into the supercritical system, the use of thermosensitive polymers, pulsed electric fields, and the combination of technologies such as aqueous two - phase synergy are not disclosed in the prior art. These combinations of technologies produce effects such as high selectivity, low energy consumption, and high purity.

[0216] Conclusion:

[0217] Both Example 1 and Example 2 are committed to solving the problem of the synergistic dissociation of the polysaccharide -

[0218] ursolic acid co - solubility system. The two achieve this through different methods (biomimetic enzymatic hydrolysis -

[0219] supercritical coupling and pulsed electric field -

[0220] aqueous two - phase coupling), respectively meeting the high - purity requirements of the laboratory and the industrial efficiency requirements. They show many advantages in solving the core problem, effectively improving the extraction technology level, providing a practical solution for the extraction of ursolic acid triterpenoid acids from jujubes, and promoting the progress of technology in this field.

Claims

1. An extraction technique for ursolic acid triterpenic acid in red dates, characterized in that, It includes the following steps: Crush dried red dates to 40-60 mesh, add acetic acid buffer solution with pH 5.5 according to the solid-liquid ratio of 1:10 g / mL, and sequentially add 1000 U / g β-glucosidase, 800 U / g pectin methyl esterase and 1500 U / g cellulase, and react at a constant temperature of 45 °C with shaking for 2.5 hours; Transfer the enzymatically hydrolyzed material into a supercritical extraction device, using 1-butyl-3-methylimidazolium chloride with a water content of 5% as an entrainer, accounting for 8% of the CO2 flow rate. Extract for 90 minutes at a temperature of 38 °C, a pressure of 15 MPa, and a CO2 flow rate of 20 L / h. During the extraction process, monitor the characteristic absorption peak of ursolic acid at 1705 cm -1 intensity by online infrared spectroscopy, and terminate the extraction when the signal intensity tends to be stable; The extraction phase is heated under reduced pressure to 50 °C and CO2 is released at 0.1 MPa, and the ionic liquid phase rich in ursolic acid is collected. Add 3 times the volume of the thermosensitive solvent aqueous solution of N-isopropylacrylamide with a concentration of 20% to the ionic liquid phase, stir at 60 °C for 30 minutes and then cool to 25 °C to trigger the lower critical solution temperature effect of NIPAM, so that ursolic acid precipitates in the form of nanocrystals, and the crude extract is obtained after centrifugation; Using ursolic acid as the template molecule, prepare a specific adsorption resin MIPs by surface molecular imprinting technology. Dissolve the crude extract in a solution with a volume ratio of methanol to water of 7:3, pass it through the MIPs column at a flow rate of 1 mL / min, first elute the residual polysaccharides with 5% ethanol aqueous solution, and then elute the target substance with a solution with a volume ratio of acetonitrile to acetic acid of 9:1, collect the eluate and freeze-dry it.

2. The extraction technique of ursolic acid triterpenic acid in red dates according to claim 1, characterized in that: The anhydrous solvent system in the supercritical extraction device is aromatic hydrocarbon, fatty alcohol or a mixture thereof, and the water content of the anhydrous solvent system is less than 100 ppm.

3. The extraction technique of ursolic acid triterpenic acid in red dates according to claim 1, characterized in that: β-Glucosidase, pectin methyl esterase and cellulase are screened by orthogonal experiments.

4. The extraction technique of ursolic acid triterpenic acid in red dates as described in claim 1, characterized in that: During the molecular imprinting solid-phase extraction process, the specific adsorption capacity of MIPs for ursolic acid is not less than 150 mg / g.

5. The extraction technique of ursolic acid triterpenic acid in red dates as described in claim 1, characterized in that: The particle size of the crushed dried red dates is uniform, and the proportion of particles in the range of 40 to 60 mesh is not less than 90%.

6. The extraction technique of ursolic acid triterpenic acid in red dates according to claim 1, characterized in that: The pH value of the thermosensitive solvent aqueous solution of N-isopropylacrylamide NIPAM is between 6.8 and 7.

2.

7. The extraction technique of ursolic acid triterpenic acid in red dates according to claim 1, characterized in that: During the supercritical CO2 extraction process, the pressure fluctuation range is controlled within ±0.5 MPa, and the temperature fluctuation range is controlled within ±2 °C.

8. The extraction technique of ursolic acid triterpenic acid in red dates according to claim 1, characterized in that: The specific adsorption resin MIPs prepared by surface molecular imprinting technology has a pore size distribution between 5 and 50 nm.

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