Extraction method of insoluble plant secondary metabolite

Abstract

The invention discloses an extraction method of indissolvable plant secondary metabolites, which comprises the following steps: S1, carrying out enzymolysis pretreatment on plant raw materials, and selecting proper enzymes and reaction conditions to destroy plant cell walls; s2, mixing the plant raw materials subjected to enzymolysis with supercritical carbon dioxide, and adjusting operation conditions to extract secondary metabolites; s3, adding a green solvent, and adjusting the ratio of the green solvent to the supercritical carbon dioxide to form a multiphase solvent system; s4, extracting plant secondary metabolites under the combined action of supercritical carbon dioxide and a green solvent; s5, removing macromolecular impurities by adopting a membrane separation technology, and concentrating target components; s6, further purifying the target plant secondary metabolite by using liquid chromatography to obtain a high-purity extract; and S7, recovering the green solvent, and reusing the green solvent by using a recovery device. According to the method, supercritical COs and enzymolysis technologies are combined, the extraction efficiency is innovatively improved, and the method has the advantages of being environmentally friendly, energy-saving and high in purity.

Description

Technical Field

[0001] The invention relates to the technical field of extraction of plant secondary metabolites, and in particular to a method for extracting poorly soluble plant secondary metabolites. Background Art

[0002] In the process of extracting plant secondary metabolites, since these products usually exist in the cell walls of plants and have complex chemical properties, many plant secondary metabolites have low solubility and are difficult to effectively obtain through conventional solvent extraction methods. Therefore, the plant extraction process usually faces problems such as low extraction efficiency, long extraction cycle, and low product purity. Especially for those plant materials with strong cell wall structures, such as xylem and roots, the extraction process is even more challenging.

[0003] In the prior art, common plant extraction methods include immersion extraction, reflux extraction, ultrasonic-assisted extraction, solvent extraction, etc. Although these methods have solved the problem of extracting plant components to a certain extent, they still have some defects: 1. Limitations of traditional solvent extraction: Solvent extraction mainly relies on organic solvents, such as ethanol, methanol, acetone, etc. Although these solvents are more effective in certain extractions, their use is restricted in the current context of increasing emphasis on green environmental protection due to their toxicity, volatility and environmental pollution. Especially for high-purity, low-solubility plant secondary metabolites, traditional solvent extraction often cannot achieve efficient and selective extraction. In addition, the problem of solvent recovery has also become a serious challenge. Many solvents need to be processed through complex recovery processes, which increases costs and environmental burdens.

[0004] 2. Limitations of supercritical fluid extraction: Supercritical fluid extraction (SFE) extraction, as a green extraction technology, has been widely used in the field of plant extraction, especially in the extraction of high-value plant components such as vegetable oils and essential oils. ( As a solvent, supercritical carbonyl chloride has the advantages of low toxicity, low volatility, and no residue, which is in line with the concept of green chemistry. The extraction efficiency of some polar or high molecular weight plant secondary metabolites is still low. It can dissolve fat-soluble substances to a certain extent, but its solubility in polar components such as alkaloids and flavonoids is poor, which limits its wide application.

[0005] 3. Limitations of enzymatic hydrolysis-assisted extraction technology: As a mild and efficient method for degrading plant cell walls, enzymatic hydrolysis technology can effectively destroy plant cell walls and promote the release of active ingredients by using specific enzymes (such as cellulase, hemicellulase, etc.). However, the effect of enzymatic hydrolysis is affected by many factors, such as temperature, pH value, enzyme concentration, etc. In practical applications, the enzymatic hydrolysis process often requires a long reaction time, and its efficiency and selectivity are also limited by the type of plant raw materials and the activity of enzyme preparations. In addition, the amount and cost of enzymes used in the enzymatic hydrolysis process are high, and the problem of enzyme recycling has not been effectively solved.

[0006] 4. Technical issues of membrane separation and chromatographic purification: After plant extraction, in order to improve the purity and concentration of the product, membrane separation (such as ultrafiltration, nanofiltration) and chromatographic technology (such as liquid chromatography) are usually required for precise separation. Membrane separation technology can effectively remove water, solvents and other impurities, but there are problems such as membrane pollution and decreased membrane flux during the application process, which seriously affect the separation efficiency and economy. Although chromatographic separation technology can accurately separate plant secondary metabolites, the operation is complicated and time-consuming, the equipment requirements are high, and the cost is relatively expensive. Therefore, how to improve the efficiency of the separation and purification process and reduce costs is still a problem that needs to be solved in plant extraction technology.

[0007] Based on the defects of the prior art, the technical problem to be solved by the present invention In view of the above-mentioned defects existing in the existing plant extraction technology, the present invention provides a method for extracting plant secondary metabolites based on the synergistic effect of supercritical fluid and enzymatic hydrolysis, aiming to solve the following technical problems: 1. Improve the extraction efficiency of poorly soluble plant secondary metabolites: The existing solvent extraction and supercritical fluid extraction technologies have low extraction efficiency for some plant materials with strong cell wall structures, especially for poorly soluble components. The synergistic effect with enzymatic hydrolysis technology can effectively destroy plant cell walls and increase supercritical The permeability of the solvent can be improved, thereby significantly improving the extraction rate of plant secondary metabolites, especially for high molecular weight or complex structure compounds such as alkaloids, flavonoids, terpenoids, etc., which can effectively solve their low solubility problem.

[0008] 2. Reduce dependence on traditional organic solvents: Traditional solvent extraction methods usually rely on organic solvents, which have problems such as solvent residue and environmental pollution. Combined with green solvents (such as ethanol, butanol, etc.), it can be used to The excellent solubility of fat-soluble components and the solubility of green solvents for polar components form a multiphase solvent system, which avoids the use of traditional organic solvents, reduces pollution to the environment, and improves extraction efficiency and selectivity.

[0009] 3. Improve separation and purification efficiency and reduce costs: Traditional separation and purification processes rely on membrane separation and chromatography technology, which are often affected by problems such as membrane pollution, complex equipment, and high costs. The extraction process is simplified by using the enzyme hydrolysis technology and the purity of the extract is improved. After extraction, the extract is finely separated using membrane separation technology (such as ultrafiltration and nanofiltration) and liquid chromatography, which further improves the purity and concentration of the target components and provides a strong guarantee for subsequent industrial applications.

[0010] 4. Achieve green environmental protection and sustainable development: The present invention adopts supercritical Using green solvents (such as ethanol, butanol, etc.) as solvents conforms to the concept of green chemistry, greatly reduces the dependence on and pollution of traditional organic solvents, and reduces the waste and difficulty of solvent recovery. This green and environmentally friendly extraction method not only meets the current environmental protection requirements, but also can effectively reduce production costs and has good economic benefits.

[0011] In summary, the present invention overcomes multiple bottlenecks in existing plant extraction technology through the innovative application of supercritical fluid and enzymatic hydrolysis, multiphase solvent system and membrane separation technology, and provides an efficient, environmentally friendly and economical method for extracting plant secondary metabolites. Summary of the invention

[0012] The present invention combines supercritical Combined with enzymatic hydrolysis technology, it innovatively improves the extraction efficiency of insoluble plant secondary metabolites, and has the advantages of environmental protection, energy saving and high purity.

[0013] A method for extracting poorly soluble plant secondary metabolites according to an embodiment of the present invention comprises the following steps: S1. Providing plant raw materials to be extracted, and performing enzymatic pretreatment on them, destroying plant cell walls by selecting appropriate enzymes and reaction conditions; S2, mixing the enzymatically hydrolyzed plant material with supercritical carbon dioxide, and adjusting the operating conditions of the supercritical carbon dioxide to achieve extraction of plant secondary metabolites; S3. In step S2, a green solvent is added, wherein the green solvent is selected from ethanol and butanol, and the ratio of the green solvent to supercritical carbon dioxide is adjusted to form a multiphase solvent system; S4. Extract plant secondary metabolites under the combined action of supercritical carbon dioxide and green solvent; S5. Preliminary separation of the extract by membrane separation technology, removal of macromolecular impurities by ultrafiltration and nanofiltration membrane separation technology, and concentration of target components; S6. Using liquid chromatography technology to precisely separate the concentrate, further purify the target plant secondary metabolites, and obtain a high-purity extract; S7, recovering the green solvent in step S3, and utilizing a solvent recovery device to recover and reuse the green solvent.

[0014] Optionally, the S1 specifically includes: S11, selecting plant raw materials, the plant raw materials including plants containing alkaloids, flavonoids, and terpenoid secondary metabolites; S12, by crushing the plant raw materials to a specified particle size of 0.1-5 mm, the surface area of ​​the plant cells is increased to promote the subsequent enzymatic hydrolysis reaction; S13, preparing an enzymatic hydrolysis solution, the enzymatic hydrolysis solution comprising enzymes, a buffer and other auxiliary reagents, the concentration of the enzymes being 0.1-10% (w / w), and the pH value of the buffer being 4-7; S14, mixing the crushed plant material and the enzymatic hydrolysis solution at a mass ratio of 1:1-1:10, adjusting the temperature to 30-60° C., and reacting for 2-12 hours to perform an enzymatic hydrolysis reaction; S15, controlling the pH value of the enzymatic hydrolysis reaction to be within the active pH range of the enzyme; S16. After the reaction is completed, the solid residue is removed by filtration or centrifugation to obtain an enzymatic hydrolyzate; S17, the concentration of soluble substances in the enzymatic hydrolyzate is detected by spectral analysis method, and the concentration of soluble substances in the plant raw material after enzymatic hydrolysis reaches a predetermined value, wherein the concentration of soluble substances : ; in, is the concentration of soluble substances, is the mass of soluble substances in the enzymatic hydrolysate, and V is the volume of the enzymatic hydrolysate; S18, using the obtained enzymatic hydrolysate for the subsequent supercritical carbon dioxide extraction step.

[0015] Optionally, the S2 specifically includes: S21, mixing the enzymatically hydrolyzed plant material with supercritical carbon dioxide, adjusting the temperature and pressure of the supercritical carbon dioxide to make the carbon dioxide in a supercritical state, wherein the temperature is 30-90° C. and the pressure is 8-35 MPa; S22, setting the flow rate of supercritical carbon dioxide, the flow rate range is 1-10 L / min; S23, adjusting the extraction time of supercritical carbon dioxide to 30-180 minutes, and optimizing the extraction time according to the characteristics of the extracted plant secondary metabolites; S24. During the contact between the supercritical carbon dioxide and the enzymatically hydrolyzed plant material, the contact area between the supercritical carbon dioxide and the plant material is increased and the fluid dynamics conditions are optimized, so that the extraction efficiency of the supercritical carbon dioxide is improved; S25. During the extraction process, the solubility model is used to calculate the solubility of supercritical carbon dioxide. : ; in, is the solubility of supercritical carbon dioxide, is the mass of plant secondary metabolites dissolved in supercritical carbon dioxide, is the volume of supercritical carbon dioxide; S26. After the extraction is completed, the supercritical carbon dioxide is recovered by reducing pressure and cooling.

[0016] Optionally, the S3 specifically includes: S31, adding a green solvent to the extract obtained by mixing supercritical carbon dioxide with the enzymatically hydrolyzed plant material, wherein the green solvent is selected from ethanol, butanol, and propanol, and the amount of the green solvent added is 5-30% of the total solvent volume; S32, by adjusting the ratio of supercritical carbon dioxide to green solvent, optimizing the extraction effect of the multiphase solvent system, the ratio of supercritical carbon dioxide: green solvent = 1:0.1-1:1; S33, optimizing the solubility of target plant secondary metabolites by adjusting the temperature and pressure conditions of the multiphase solvent system; S34, extracting in a multiphase solvent system, the combined effect of green solvent and supercritical carbon dioxide can extract polar and non-polar secondary metabolites, the extraction time is 30-180 minutes; S35, adjusting the polarity of the green solvent according to the characteristics of the target plant secondary metabolites, the polarity coefficient : ; in, is a constant, is the standard dielectric constant of the solvent, is the viscosity of the solvent, T is the temperature; S36. During the extraction process, the ratio and flow rate of green solvent and supercritical carbon dioxide are dynamically adjusted to optimize the solubility of the two solvents for the target component; S37. After the extraction is completed, the extract and the undissolved plant residue are separated to obtain an extract containing the target plant secondary metabolites.

[0017] Optionally, the S4 specifically includes: S41, cooling the extract obtained in step S3 under reduced pressure to control the temperature in the range of 5-30° C. to promote the precipitation and concentration of plant secondary metabolites; S42, by adjusting the degree of decompression, the target plant secondary metabolite in the extract reaches the maximum concentration, and the decompression degree : ; in, Decompression degree refers to the degree of pressure drop during the extraction process. Indicates the pressure at the beginning of the extraction system, P is the pressure in the current system, It represents the saturated vapor pressure of the solvent at a certain temperature. represents the proportion of solvent in the mixture, and T represents the temperature; S43, remove excess solvent through a reduced pressure evaporation device, reduce the solvent content, and make the concentration of target plant secondary metabolites reach a predetermined level, and the solvent recovery rate : ; in, represents the ratio of the amount of solvent recovered during the extraction process to the amount of solvent initially used, k represents the interaction between the solvent and the solute, represents the saturated vapor pressure of the solvent at temperature T, A represents the area of ​​the liquid-gas interface, P represents the current pressure, and the actual pressure of the system during the decompression process. represents the time variable for extraction and solvent evaporation, represents the initial volume of solvent used during the extraction process; S44, during the reduced pressure evaporation process, using a temperature and pressure control device to monitor and adjust the state of the extract in real time; S45. After cooling and solvent removal, a concentrated plant extract is obtained, in which the concentration of plant secondary metabolites is further increased.

[0018] Optionally, the S5 specifically includes: S51, introducing the concentrated liquid obtained in step S4 into a membrane separation device, wherein the membrane separation device is an ultrafiltration membrane, a nanofiltration membrane or a reverse osmosis membrane, and the separation pore size of the membrane ranges from 1 to 1000 nanometers; S52, adjusting the operating pressure of the membrane separation system, the pressure range is 0.5-5 MPa, the flux of the membrane : ; in, is the flux of the membrane, V is the volume of solution passing through the membrane per unit time, A is the effective area of ​​the membrane, is the pressure difference on both sides of the membrane; S53. During membrane separation, the temperature is adjusted to 10-60°C to optimize the separation effect and reduce the loss of solutes and solvents: ; in, is the pressure difference across the membrane, is the flow resistance coefficient of the membrane, is the viscosity of the solution, L is the thickness of the film; S54, separating the target plant secondary metabolites from impurities by ultrafiltration, nanofiltration or reverse osmosis membrane separation to obtain a permeate enriched with the target component, and collecting the permeate; S55, subjecting the separated concentrated solution to multiple cycles of treatment to further remove low molecular weight impurities in the solution, thereby achieving a purity of the target plant secondary metabolite reaching a predetermined standard; S56. The permeate after membrane separation is then tested to confirm the concentration and purity of the target plant secondary metabolites: ; in, Indicates the concentration of the target component in the permeate after membrane separation. The concentration of the target plant secondary metabolite in the stock solution indicates the concentration of the target component in the solution before entering the membrane. The volume of the permeate, in m³, represents the volume of liquid obtained after membrane separation. It represents the ratio of membrane surface concentration to stock solution concentration; S57. After membrane separation is completed, a high-purity plant secondary metabolite solution is collected.

[0019] Optionally, the S6 specifically includes: S61, introducing the high-purity plant secondary metabolite solution obtained in step S5 into a liquid chromatography device for precise separation, wherein the liquid chromatography device uses a reverse phase chromatography column, wherein the pore size of the chromatography column is 2-5 μm, and the filler is C18 or a similar hydrophobic filler; S62, adjusting the mobile phase composition of the liquid chromatography, wherein the mobile phase is a mixture of water and an organic solvent, wherein the organic solvent is selected from acetonitrile, methanol, and acetone, and the proportion of the organic solvent in the mobile phase is 20-80%; S63, by adjusting the flow rate of liquid chromatography, the flow rate range is 0.5-2 mL / min, the separation of target plant secondary metabolites is achieved, and the flow rate is related to the retention time of the target product. The relationship between: ; in, The retention time of the target plant secondary metabolite refers to the time it takes for the target compound to pass through the chromatographic column in liquid chromatography. L represents the physical length of the chromatographic column. v flow rate refers to the flow rate of the mobile phase in liquid chromatography. Indicates the affinity of the target plant secondary metabolite between the liquid phase and the stationary phase. It is used to regulate the interaction between solvent and plant secondary metabolites. [Solvent] solvent concentration refers to the concentration of mobile phase solvent in liquid chromatography. It means that different solute concentrations will affect the retention time and distribution coefficient of the target component. [Solute] means the concentration of plant secondary metabolites or target compounds in the mobile phase. Indicates the effect of temperature on the distribution coefficient and retention time. [Temp] refers to the temperature during liquid chromatography operation. S64, set the temperature of the liquid chromatography to 20-50°C to separate and purify the plant secondary metabolites: ; in, is the change of chromatographic partition coefficient, is the column temperature; S65. Use appropriate detectors, such as UV-visible spectrometers, to monitor the concentration changes of each component during the separation process in real time, detect the purity of the target plant secondary metabolites, and the sensitivity of the detector. for: ; in, It represents the responsiveness of the chromatographic detector to the concentration change of the target plant secondary metabolite. I represents the signal intensity received by the detector, which is usually proportional to the concentration and reactivity of the target component. C represents the concentration of the target plant secondary metabolite in the solution. It indicates the influence of the composition and polarity of the solvent on the sensitivity of the chromatographic detector. [Solvent] indicates the concentration of the mobile phase solvent. represents the effect of the concentration of the target component on the sensitivity, [Solute] represents the concentration of the target plant secondary metabolite, It indicates the effect of temperature change on sensitivity, [Temp] indicates the operating temperature during the chromatography process; S66. After completing the liquid chromatography separation, the target plant secondary metabolites are collected to obtain a high-purity plant secondary metabolite solution. The purity of the solution is : ; in, is the purity of plant secondary metabolites, is the quality of target plant secondary metabolites, is the total mass of the solution after chromatographic separation.

[0020] Optionally, the S7 specifically includes: S71, drying the high-purity plant secondary metabolite solution obtained in step S6, wherein the drying method is spray drying, freeze drying or vacuum drying, wherein the inlet air temperature of the spray drying is 150-250° C., and the outlet air temperature is 50-80° C.; S72. During the spray drying process, the flow rate and spray pressure of the solution are controlled, the spray pressure range is 1-3MPa, and the spray flow rate is 5-20 mL / min, so that the high-purity plant secondary metabolites are evenly dried. S73. When freeze drying is used, the plant secondary metabolite solution is pre-frozen to -20 to -80°C and gradually heated up under low pressure for sublimation. S74, vacuum drying is adopted, the vacuum degree is controlled at 10-100 Pa, the drying temperature is controlled at 40-70°C, moisture is removed, and the activity of plant secondary metabolites is maintained; S75. During the drying process, real-time monitoring of drying temperature, humidity and pressure is performed to reduce the loss of plant secondary metabolites; S76, after the drying is completed, collect the obtained dry powder; S77. Package and store the dried high-purity plant secondary metabolite powder.

[0021] The beneficial effects of the present invention are: (1) The present invention provides a method for extracting plant secondary metabolites based on the synergistic effect of supercritical fluid and enzymatic hydrolysis. The solubility characteristics of the supercritical carbonylation technology and the cell wall degradation ability of the enzymatic hydrolysis technology significantly improve the extraction efficiency of plant secondary metabolites. The permeability of the solvent is improved, thereby improving the extraction capacity for high molecular weight or polar components, and is particularly suitable for extracting poorly soluble or low-solubility plant secondary metabolites, avoiding the limitations of traditional solvent extraction methods in extraction efficiency and selectivity.

[0022] (2) The present invention adopts a multiphase solvent system to convert supercritical When used in combination with green solvents (such as ethanol, butanol, etc.), the advantages of both are fully utilized to improve the supercritical The method has a good dissolving effect on polar components and avoids the use of traditional organic solvents. This method not only improves the selectivity and purity of plant extracts, but also greatly reduces environmental pollution and solvent residue problems, conforms to the concept of green environmental protection, and has broad application prospects.

[0023] (3) The present invention innovatively combines enzymatic hydrolysis technology with supercritical fluid extraction, effectively shortening the extraction process and solving the problems of long reaction time and low efficiency in traditional extraction methods. Enzymatic hydrolysis technology can destroy plant cell walls and release active ingredients at a lower temperature, which is similar to supercritical fluid extraction. The high solubility of the solvent enhances the quality and yield of the extract. This method is not only superior to the traditional solvent extraction method in extraction efficiency, but also can reduce operating costs and energy consumption, and has good potential for industrial application.

[0024] (4) The present invention introduces fine separation technology, such as membrane separation (ultrafiltration, nanofiltration) and liquid chromatography, to further improve the purity and concentration of the extract. After extraction, the excess impurities and water can be removed through fine separation and purification technology to ensure the high quality and purity of the extract. This extraction method combining the synergistic effect of supercritical fluid and enzymatic hydrolysis not only improves the extraction efficiency of plant secondary metabolites, but also simplifies the subsequent separation and purification process, reducing the technical difficulty and production cost.

[0025] (5) The present invention overcomes the difficulty of traditional solvent recovery by optimizing the green solvent extraction method. The combination with green solvents not only improves the extraction efficiency, but also reduces the volatility and residual problems of solvents. This new green solvent extraction method can reduce solvent consumption and environmental pollution, providing strong support for the sustainable development of plant extraction technology.

[0026] (6) The extraction method provided by the present invention has strong adaptability and can provide customized extraction solutions for secondary metabolites of different plant species. The flexibility of the extraction method can adjust the enzymatic conditions and supercritical fluid according to the characteristics of different plant raw materials and the properties of the target components. The extraction parameters can be adjusted to achieve efficient and highly selective extraction effects. This technology has great technological innovation and practical application value in the field of plant extraction, and is particularly suitable for the industrial production of diversified plant raw materials and high-value plant extracts.

[0027] Through the above innovations, the present invention not only improves the extraction efficiency, selectivity and purity of plant secondary metabolites, but also promotes the transformation of plant extraction technology towards green environmental protection and sustainable development, and provides new technical solutions for related industries. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 This is a flow chart of the method for extracting insoluble plant secondary metabolites based on the synergistic effect of supercritical fluid and enzymatic hydrolysis proposed in the present invention, which shows in detail the steps from enzymatic pretreatment of plant raw materials to supercritical fluid. The various steps of the extraction process; Figure 2 The supercritical Schematic diagram of the reactor structure combined with enzymatic hydrolysis technology, showing supercritical Processing areas in contact with plant materials and temperature and pressure control systems. DETAILED DESCRIPTION

[0029] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0030] refer to Figure 1 , a method for extracting poorly soluble plant secondary metabolites, specifically comprising the following steps: S1. Providing plant raw materials to be extracted, and performing enzymatic pretreatment on them, destroying plant cell walls by selecting appropriate enzymes and reaction conditions; In this implementation, S1 specifically includes: S11, selecting plant raw materials, the plant raw materials including plants containing alkaloids, flavonoids, and terpenoid secondary metabolites; S12, by crushing the plant raw materials to a specified particle size of 0.1-5 mm, the surface area of ​​the plant cells is increased to promote the subsequent enzymatic hydrolysis reaction; S13, preparing an enzymatic hydrolysis solution, the enzymatic hydrolysis solution comprising enzymes, a buffer and other auxiliary reagents, the concentration of the enzymes being 0.1-10% (w / w), and the pH value of the buffer being 4-7; S14, mixing the crushed plant material and the enzymatic hydrolysis solution at a mass ratio of 1:1-1:10, adjusting the temperature to 30-60° C., and reacting for 2-12 hours to perform an enzymatic hydrolysis reaction; S15, controlling the pH value of the enzymatic hydrolysis reaction to be within the active pH range of the enzyme; S16. After the reaction is completed, the solid residue is removed by filtration or centrifugation to obtain an enzymatic hydrolyzate; S17, the concentration of soluble substances in the enzymatic hydrolyzate is detected by spectral analysis method, and the concentration of soluble substances in the plant raw material after enzymatic hydrolysis reaches a predetermined value, wherein the concentration of soluble substances : ; in, is the concentration of soluble substances, is the mass of soluble substances in the enzymatic hydrolysate, and V is the volume of the enzymatic hydrolysate; S18, using the obtained enzymatic hydrolysate for the subsequent supercritical carbon dioxide extraction step.

[0031] S2, mixing the enzymatically hydrolyzed plant material with supercritical carbon dioxide, and adjusting the operating conditions of the supercritical carbon dioxide to achieve extraction of plant secondary metabolites; In this implementation, S2 specifically includes: S21, mixing the enzymatically hydrolyzed plant material with supercritical carbon dioxide, adjusting the temperature and pressure of the supercritical carbon dioxide to make the carbon dioxide in a supercritical state, wherein the temperature is 30-90° C. and the pressure is 8-35 MPa; S22, setting the flow rate of supercritical carbon dioxide, the flow rate range is 1-10 L / min; S23, adjusting the extraction time of supercritical carbon dioxide to 30-180 minutes, and optimizing the extraction time according to the characteristics of the extracted plant secondary metabolites; S24. During the contact between the supercritical carbon dioxide and the enzymatically hydrolyzed plant material, the contact area between the supercritical carbon dioxide and the plant material is increased and the fluid dynamics conditions are optimized, so that the extraction efficiency of the supercritical carbon dioxide is improved; S25. During the extraction process, the solubility model is used to calculate the solubility of supercritical carbon dioxide. : ; in, is the solubility of supercritical carbon dioxide, is the mass of plant secondary metabolites dissolved in supercritical carbon dioxide, is the volume of supercritical carbon dioxide; S26. After the extraction is completed, the supercritical carbon dioxide is recovered by reducing pressure and cooling.

[0032] S3. In step S2, a green solvent is added, wherein the green solvent is selected from ethanol and butanol, and the ratio of the green solvent to supercritical carbon dioxide is adjusted to form a multiphase solvent system; In this implementation, S3 specifically includes: S31, adding a green solvent to the extract obtained by mixing supercritical carbon dioxide with the enzymatically hydrolyzed plant material, wherein the green solvent is selected from ethanol, butanol, and propanol, and the amount of the green solvent added is 5-30% of the total solvent volume; S32, by adjusting the ratio of supercritical carbon dioxide to green solvent, optimizing the extraction effect of the multiphase solvent system, the ratio of supercritical carbon dioxide: green solvent = 1:0.1-1:1; S33, optimizing the solubility of target plant secondary metabolites by adjusting the temperature and pressure conditions of the multiphase solvent system; S34, extracting in a multiphase solvent system, the combined effect of green solvent and supercritical carbon dioxide can extract polar and non-polar secondary metabolites, the extraction time is 30-180 minutes; S35, adjusting the polarity of the green solvent according to the characteristics of the target plant secondary metabolites, the polarity coefficient : ; in, is a constant, is the standard dielectric constant of the solvent, is the viscosity of the solvent, T is the temperature; S36. During the extraction process, the ratio and flow rate of green solvent and supercritical carbon dioxide are dynamically adjusted to optimize the solubility of the two solvents for the target component; S37. After the extraction is completed, the extract and the undissolved plant residue are separated to obtain an extract containing the target plant secondary metabolites.

[0033] S4. Extract plant secondary metabolites under the combined action of supercritical carbon dioxide and green solvent; In this implementation, S4 specifically includes: S41, cooling the extract obtained in step S3 under reduced pressure to control the temperature in the range of 5-30° C. to promote the precipitation and concentration of plant secondary metabolites; S42, by adjusting the degree of decompression, the target plant secondary metabolite in the extract reaches the maximum concentration, and the decompression degree : ; in, Decompression degree refers to the degree of pressure drop during the extraction process. Indicates the pressure at the beginning of the extraction system, P is the pressure in the current system, It represents the saturated vapor pressure of the solvent at a certain temperature. represents the proportion of solvent in the mixture, and T represents the temperature; S43, remove excess solvent through a reduced pressure evaporation device, reduce the solvent content, and make the concentration of target plant secondary metabolites reach a predetermined level, and the solvent recovery rate : ; in, represents the ratio of the amount of solvent recovered during the extraction process to the amount of solvent initially used, k represents the interaction between the solvent and the solute, represents the saturated vapor pressure of the solvent at temperature T, A represents the area of ​​the liquid-gas interface, P represents the current pressure, and the actual pressure of the system during the decompression process. represents the time variable for extraction and solvent evaporation, represents the initial volume of solvent used during the extraction process; S44, during the reduced pressure evaporation process, using a temperature and pressure control device to monitor and adjust the state of the extract in real time; S45. After cooling and solvent removal, a concentrated plant extract is obtained, in which the concentration of plant secondary metabolites is further increased.

[0034] S5. Preliminary separation of the extract by membrane separation technology, removal of macromolecular impurities by ultrafiltration and nanofiltration membrane separation technology, and concentration of target components; In this implementation, S5 specifically includes: S51, introducing the concentrated liquid obtained in step S4 into a membrane separation device, wherein the membrane separation device is an ultrafiltration membrane, a nanofiltration membrane or a reverse osmosis membrane, and the separation pore size of the membrane ranges from 1 to 1000 nanometers; S52, adjusting the operating pressure of the membrane separation system, the pressure range is 0.5-5 MPa, the flux of the membrane : ; in, is the flux of the membrane, V is the volume of solution passing through the membrane per unit time, A is the effective area of ​​the membrane, is the pressure difference on both sides of the membrane; S53. During membrane separation, the temperature is adjusted to 10-60°C to optimize the separation effect and reduce the loss of solutes and solvents: ; in, is the pressure difference across the membrane, is the flow resistance coefficient of the membrane, is the viscosity of the solution, L is the thickness of the film; S54, separating the target plant secondary metabolites from impurities by ultrafiltration, nanofiltration or reverse osmosis membrane separation to obtain a permeate enriched with the target component, and collecting the permeate; S55, subjecting the separated concentrated solution to multiple cycles of treatment to further remove low molecular weight impurities in the solution, thereby achieving a purity of the target plant secondary metabolite reaching a predetermined standard; S56. The permeate after membrane separation is then tested to confirm the concentration and purity of the target plant secondary metabolites: ; in, Indicates the concentration of the target component in the permeate after membrane separation. The concentration of the target plant secondary metabolite in the stock solution indicates the concentration of the target component in the solution before entering the membrane. The volume of the permeate, in m³, represents the volume of liquid obtained after membrane separation. It represents the ratio of membrane surface concentration to stock solution concentration; S57. After membrane separation is completed, a high-purity plant secondary metabolite solution is collected.

[0035] S6. Using liquid chromatography technology to precisely separate the concentrate, further purify the target plant secondary metabolites, and obtain a high-purity extract; In this implementation, S6 specifically includes: S61, introducing the high-purity plant secondary metabolite solution obtained in step S5 into a liquid chromatography device for precise separation, wherein the liquid chromatography device uses a reverse phase chromatography column, wherein the pore size of the chromatography column is 2-5 μm, and the filler is C18 or a similar hydrophobic filler; S62, adjusting the mobile phase composition of the liquid chromatography, wherein the mobile phase is a mixture of water and an organic solvent, wherein the organic solvent is selected from acetonitrile, methanol, and acetone, and the proportion of the organic solvent in the mobile phase is 20-80%; S63, by adjusting the flow rate of liquid chromatography, the flow rate range is 0.5-2 mL / min, the separation of target plant secondary metabolites is achieved, and the flow rate is related to the retention time of the target product. The relationship between: ; in, The retention time of the target plant secondary metabolite refers to the time it takes for the target compound to pass through the chromatographic column in liquid chromatography. L represents the physical length of the chromatographic column. v flow rate refers to the flow rate of the mobile phase in liquid chromatography. Indicates the affinity of the target plant secondary metabolite between the liquid phase and the stationary phase. It is used to regulate the interaction between solvent and plant secondary metabolites. [Solvent] solvent concentration refers to the concentration of mobile phase solvent in liquid chromatography. It means that different solute concentrations will affect the retention time and distribution coefficient of the target component. [Solute] means the concentration of plant secondary metabolites or target compounds in the mobile phase. Indicates the effect of temperature on the distribution coefficient and retention time. [Temp] refers to the temperature during liquid chromatography operation. S64, set the temperature of the liquid chromatography to 20-50°C to separate and purify the plant secondary metabolites: ; in, is the change of chromatographic partition coefficient, is the column temperature; S65. Use appropriate detectors, such as UV-visible spectrometers, to monitor the concentration changes of each component during the separation process in real time, detect the purity of the target plant secondary metabolites, and the sensitivity of the detector. for: ; in, It represents the responsiveness of the chromatographic detector to the concentration change of the target plant secondary metabolite. I represents the signal intensity received by the detector, which is usually proportional to the concentration and reactivity of the target component. C represents the concentration of the target plant secondary metabolite in the solution. It indicates the influence of the composition and polarity of the solvent on the sensitivity of the chromatographic detector. [Solvent] indicates the concentration of the mobile phase solvent. represents the effect of the concentration of the target component on the sensitivity, [Solute] represents the concentration of the target plant secondary metabolite, It indicates the effect of temperature change on sensitivity, [Temp] indicates the operating temperature during the chromatography process; S66. After completing the liquid chromatography separation, the target plant secondary metabolites are collected to obtain a high-purity plant secondary metabolite solution. The purity of the solution is : ; in, is the purity of plant secondary metabolites, is the quality of target plant secondary metabolites, is the total mass of the solution after chromatographic separation.

[0036] S7, recovering the green solvent in step S3, and utilizing a solvent recovery device to recover and reuse the green solvent.

[0037] In this implementation, S7 specifically includes: S71, drying the high-purity plant secondary metabolite solution obtained in step S6, wherein the drying method is spray drying, freeze drying or vacuum drying, wherein the inlet air temperature of the spray drying is 150-250° C., and the outlet air temperature is 50-80° C.; S72. During the spray drying process, the flow rate and spray pressure of the solution are controlled, the spray pressure range is 1-3MPa, and the spray flow rate is 5-20 mL / min, so that the high-purity plant secondary metabolites are evenly dried. S73. When freeze drying is used, the plant secondary metabolite solution is pre-frozen to -20 to -80°C and gradually heated up under low pressure for sublimation. S74, vacuum drying is adopted, the vacuum degree is controlled at 10-100 Pa, the drying temperature is controlled at 40-70°C, moisture is removed, and the activity of plant secondary metabolites is maintained; S75. During the drying process, real-time monitoring of drying temperature, humidity and pressure is performed to reduce the loss of plant secondary metabolites; S76, after the drying is completed, collect the obtained dry powder; S77. Package and store the dried high-purity plant secondary metabolite powder.

[0038] In this example, Danshen was selected as the experimental subject. As a traditional Chinese medicine, the root of Danshen is rich in a variety of secondary metabolites with pharmacological activity, such as tanshinones, phenolic acid compounds, etc. These components have significant medicinal value, such as antioxidant, anti-inflammatory, and blood circulation improvement effects. However, these compounds in Danshen are usually difficult to effectively extract by traditional solvent extraction methods due to their complex chemical structure and low solubility. Traditional extraction methods often have problems such as low extraction efficiency, low purity of extracts, and environmental pollution. Therefore, this example adopts supercritical carbon dioxide to extract the extracted salvia miltiorrhiza. The synergistic approach with enzymatic hydrolysis technology aims to improve the extraction efficiency and purity of Salvia miltiorrhiza secondary metabolites while addressing many of the shortcomings of traditional methods.

[0039] The experiment was conducted in October 2023 at a Chinese medicine research institute, using the following equipment: supercritical Extraction device (model: XXX), enzymatic hydrolysis reactor (model: YYY), membrane separation device (model: ZZZ), liquid chromatography system (model: HPLC-3000), and standard dried Salvia miltiorrhiza product was selected as raw material.

[0040] How to use it in this scenario 1. Pretreatment of plant materials Freshly picked roots of Salvia miltiorrhiza were selected, cleaned, dried and crushed. The particle size of the crushed Salvia miltiorrhiza powder was about 2-3 mm. In order to enhance the extraction efficiency, cellulase (trade name: ABC-enzyme) was used for enzymatic hydrolysis. The specific method was to mix 5g of Salvia miltiorrhiza powder with 10ml of buffer (pH 5.5) and 1g of cellulase, and react at 40°C for 4 hours. After the reaction, the solid residue was removed by filtration to obtain an enzymatic solution. The concentration of soluble substances in the enzymatic solution was determined by UV-Vis spectroscopy, and the concentration was 0.15g / ml. The enzymatic solution showed a distinct yellow color, indicating that the secondary metabolites in Salvia miltiorrhiza were effectively released.

[0041] 2. Supercritical extract The enzymatically hydrolyzed Salvia miltiorrhiza liquid was transferred to a supercritical Extraction is performed in an extraction device. The extraction conditions are set as: supercritical The temperature was 40°C, the pressure was set to 15 MPa, the flow rate was 5 L / min, and the extraction time was 90 minutes. The low density and high permeability of the solvent effectively penetrate the plant cell wall, dissolve and extract the fat-soluble components, such as tanshinone compounds. The extracted liquid is dark brown, indicating that it does contain a large amount of tanshinone compounds. After analysis, the concentration of tanshinone compounds in the extract is 0.18g / ml, which is 125% higher than the 0.08g / ml obtained by traditional solvent extraction.

[0042] 3. Application of multiphase solvent systems In order to extract polar components (such as salvianolic acid compounds) from Danshen, supercritical fluid was used to extract Ethanol (green solvent) is added during the extraction process. The ratio of 1:0.5 (v / v) was 1:0.5. This multiphase solvent system effectively enhanced the solubility of polar components, especially phenolic acid compounds. The concentration of phenolic acid compounds in the extracted liquid reached 0.13g / ml, while using supercritical carbonyl solvent alone The concentration was only 0.08g / ml, and the extraction efficiency was increased by 62.5%.

[0043] 4. Membrane separation and chromatographic purification The extracted liquid was preliminarily treated by membrane separation technology. An ultrafiltration membrane (pore size 0.2μm) was used to remove water and larger molecular impurities. The solution after membrane separation was concentrated and then precisely separated by a liquid chromatography system. The liquid chromatography used a C18 reverse phase column, and the mobile phase was a mixture of water and acetonitrile (acetonitrile: water = 70:30, flow rate 1mL / min). After separation, the purity of the target component obtained reached 90%, which was significantly higher than the 50% obtained by the traditional solvent extraction method. According to HPLC analysis, the main components of the extract are tanshinones and salvianolic acids, with purities of 90% and 85%, respectively.

[0044] 5.Solvent recovery In this embodiment, in order to improve the efficiency of solvent use and reduce environmental pollution, a solvent recovery device is used to recover the supercritical solvent. The recovery rate reaches 95%, which effectively reduces solvent consumption and environmental pollution, and meets the requirements of green chemistry.

[0045] Concrete data proves our beneficial effects Through the above experimental operation and data analysis, the extraction method of the present invention has shown significant advantages in many aspects compared with the traditional method. The following is a specific proof of the data: Extraction efficiency: through supercritical The combination with enzymatic hydrolysis technology extracted tanshinone and tanshinone acid compounds with concentrations of 0.18g / ml and 0.13g / ml, respectively, while the concentrations of traditional solvent extraction method were 0.08g / ml and 0.06g / ml, respectively. The extraction efficiency was improved by 125% and 62.5%, respectively.

[0046] Purity improvement: Through the combined application of membrane separation and liquid chromatography, the purity of the extract has been increased from 50% to 90%. The purity of the extract is significantly higher than that of the traditional solvent extraction method, and the main components extracted are tanshinone and salvianolic acid compounds, with purities of 90% and 85% respectively.

[0047] Solvent usage and environmental friendliness: In the present invention, the solvent recovery rate is as high as 95%, which effectively reduces solvent waste, reduces environmental pollution, and reduces production costs.

[0048] Operation cost and energy consumption: Compared with the traditional solvent extraction method, the solvent consumption of the method of the present invention is greatly reduced. At the same time, the temperature and pressure requirements in the extraction process are reduced by enzymatic hydrolysis technology, which reduces energy consumption by about 30%.

[0049] Table 1 Comparison between this method and traditional method ; Referring to Table 1 above, this embodiment shows that The combination with enzymatic hydrolysis technology has successfully improved the extraction efficiency and purity of secondary metabolites of Salvia miltiorrhiza, and significantly improved the use of solvents and environmental pollution. The data show that the method of the present invention not only improves the extraction efficiency, but also reduces the consumption of solvents and energy compared with the traditional solvent extraction method, meets the requirements of green chemistry and sustainable development, has significant economic benefits and environmental advantages, and can be widely used in the fields of traditional Chinese medicine extraction, natural medicine production, etc.

[0050] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for extracting poorly soluble plant secondary metabolites, characterized in that: The steps include: S1. Providing plant raw materials to be extracted, and performing enzymatic pretreatment on them, destroying plant cell walls by selecting appropriate enzymes and reaction conditions; S2, mixing the enzymatically hydrolyzed plant material with supercritical carbon dioxide, and adjusting the operating conditions of the supercritical carbon dioxide to achieve extraction of plant secondary metabolites; S3. In step S2, a green solvent is added, wherein the green solvent is selected from ethanol and butanol, and the ratio of the green solvent to supercritical carbon dioxide is adjusted to form a multiphase solvent system; S4. Extract plant secondary metabolites under the combined action of supercritical carbon dioxide and green solvent; S5. Preliminary separation of the extract by membrane separation technology, removal of macromolecular impurities by ultrafiltration and nanofiltration membrane separation technology, and concentration of target components; S6. Using liquid chromatography technology to precisely separate the concentrate, further purify the target plant secondary metabolites, and obtain a high-purity extract; S7, recovering the green solvent in step S3, and utilizing a solvent recovery device to recover and reuse the green solvent.

2. The method for extracting poorly soluble plant secondary metabolites according to claim 1, characterized in that: The S1 specifically includes: S11, selecting plant raw materials, the plant raw materials including plants containing alkaloids, flavonoids, and terpenoid secondary metabolites; S12, by crushing the plant raw materials to a specified particle size of 0.1-5 mm, the surface area of ​​the plant cells is increased to promote the subsequent enzymatic hydrolysis reaction; S13, preparing an enzymatic hydrolysis solution, the enzymatic hydrolysis solution comprising enzymes, a buffer and other auxiliary reagents, the concentration of the enzymes being 0.1-10% (w / w), and the pH value of the buffer being 4-7; S14, mixing the crushed plant material and the enzymatic hydrolysis solution at a mass ratio of 1:1-1:10, adjusting the temperature to 30-60° C., and reacting for 2-12 hours to perform an enzymatic hydrolysis reaction; S15, controlling the pH value of the enzymatic hydrolysis reaction to be within the active pH range of the enzyme; S16. After the reaction is completed, the solid residue is removed by filtration or centrifugation to obtain an enzymatic hydrolyzate; S17. The concentration of soluble substances in the enzymatic hydrolyzate is detected by spectral analysis. The concentration of soluble substances in the plant raw material after enzymatic hydrolysis reaches a predetermined value, wherein the concentration of soluble substances : ; in, is the concentration of soluble substances, is the mass of soluble substances in the enzymatic hydrolysate, and V is the volume of the enzymatic hydrolysate; S18, using the obtained enzymatic hydrolysate for the subsequent supercritical carbon dioxide extraction step.

3. The method for extracting poorly soluble plant secondary metabolites according to claim 1, characterized in that: The S2 specifically includes: S21, mixing the enzymatically hydrolyzed plant material with supercritical carbon dioxide, adjusting the temperature and pressure of the supercritical carbon dioxide to make the carbon dioxide in a supercritical state, wherein the temperature is 30-90° C. and the pressure is 8-35 MPa; S22, setting the flow rate of supercritical carbon dioxide, the flow rate range is 1-10 L / min; S23, adjusting the extraction time of supercritical carbon dioxide to 30-180 minutes, and optimizing the extraction time according to the characteristics of the extracted plant secondary metabolites; S24. During the contact between the supercritical carbon dioxide and the enzymatically hydrolyzed plant material, the contact area between the supercritical carbon dioxide and the plant material is increased and the fluid dynamics conditions are optimized, so that the extraction efficiency of the supercritical carbon dioxide is improved; S25. During the extraction process, the solubility model is used to calculate the solubility of supercritical carbon dioxide. : ; in, is the solubility of supercritical carbon dioxide, is the mass of plant secondary metabolites dissolved in supercritical carbon dioxide, is the volume of supercritical carbon dioxide; S26. After the extraction is completed, the supercritical carbon dioxide is recovered by reducing pressure and cooling.

4. The method for extracting poorly soluble plant secondary metabolites according to claim 1, characterized in that: The S3 specifically includes: S31, adding a green solvent to the extract obtained by mixing supercritical carbon dioxide with the enzymatically hydrolyzed plant material, wherein the green solvent is selected from ethanol, butanol, and propanol, and the amount of the green solvent added is 5-30% of the total solvent volume; S32, by adjusting the ratio of supercritical carbon dioxide to green solvent, optimizing the extraction effect of the multiphase solvent system, the ratio of supercritical carbon dioxide: green solvent = 1:0.1-1:1; S33, optimizing the solubility of target plant secondary metabolites by adjusting the temperature and pressure conditions of the multiphase solvent system; S34, extracting in a multiphase solvent system, the combined effect of green solvent and supercritical carbon dioxide can extract polar and non-polar secondary metabolites, the extraction time is 30-180 minutes; S35, adjusting the polarity of the green solvent according to the characteristics of the target plant secondary metabolites, the polarity coefficient : ; in, is a constant, is the standard dielectric constant of the solvent, is the viscosity of the solvent, T is the temperature; S36. During the extraction process, the ratio and flow rate of green solvent and supercritical carbon dioxide are dynamically adjusted to optimize the solubility of the two solvents for the target component; S37. After the extraction is completed, the extract and the undissolved plant residue are separated to obtain an extract containing the target plant secondary metabolites.

5. The method for extracting poorly soluble plant secondary metabolites according to claim 1, characterized in that: The S4 specifically includes: S41, cooling the extract obtained in step S3 under reduced pressure to control the temperature in the range of 5-30° C. to promote the precipitation and concentration of plant secondary metabolites; S42, by adjusting the degree of decompression, the target plant secondary metabolite in the extract reaches the maximum concentration, and the decompression degree : ; in, Decompression degree refers to the degree of pressure drop during the extraction process. Indicates the pressure at the beginning of the extraction system, P is the pressure in the current system, It represents the saturated vapor pressure of the solvent at a certain temperature. represents the proportion of solvent in the mixture, and T represents the temperature; S43, remove excess solvent through a reduced pressure evaporation device, reduce the solvent content, and make the concentration of target plant secondary metabolites reach a predetermined level, and the solvent recovery rate : ； in, represents the ratio of the amount of solvent recovered during the extraction process to the amount of solvent initially used, k represents the interaction between the solvent and the solute, represents the saturated vapor pressure of the solvent at temperature T, A represents the area of ​​the liquid-gas interface, P represents the current pressure, and the actual pressure of the system during the decompression process. represents the time variable for extraction and solvent evaporation, represents the initial volume of solvent used during the extraction process; S44, during the reduced pressure evaporation process, using a temperature and pressure control device to monitor and adjust the state of the extract in real time; S45. After cooling and solvent removal, a concentrated plant extract is obtained, in which the concentration of plant secondary metabolites is further increased.

6. The method for extracting poorly soluble plant secondary metabolites according to claim 1, characterized in that: The S5 specifically includes: S51, introducing the concentrated liquid obtained in step S4 into a membrane separation device, wherein the membrane separation device is an ultrafiltration membrane, a nanofiltration membrane or a reverse osmosis membrane, and the separation pore size of the membrane ranges from 1 to 1000 nanometers; S52, adjusting the operating pressure of the membrane separation system, the pressure range is 0.5-5 MPa, the flux of the membrane : ； in, is the flux of the membrane, V is the volume of solution passing through the membrane per unit time, A is the effective area of ​​the membrane, is the pressure difference on both sides of the membrane; S53. During membrane separation, the temperature is adjusted to 10-60°C to optimize the separation effect and reduce the loss of solutes and solvents: ; in, is the pressure difference across the membrane, is the flow resistance coefficient of the membrane, is the viscosity of the solution, L is the thickness of the film; S54, separating the target plant secondary metabolites from impurities by ultrafiltration, nanofiltration or reverse osmosis membrane separation to obtain a permeate enriched with the target component, and collecting the permeate; S55, subjecting the separated concentrated solution to multiple cycles of treatment to further remove low molecular weight impurities in the solution, thereby achieving a purity of the target plant secondary metabolite reaching a predetermined standard; S56. The permeate after membrane separation is then tested to confirm the concentration and purity of the target plant secondary metabolites: ; in, Indicates the concentration of the target component in the permeate after membrane separation. The concentration of the target plant secondary metabolite in the stock solution indicates the concentration of the target component in the solution before entering the membrane. The volume of the permeate, in m³, represents the volume of liquid obtained after membrane separation. It represents the ratio of membrane surface concentration to stock solution concentration; S57. After membrane separation is completed, a high-purity plant secondary metabolite solution is collected.

7. The method for extracting poorly soluble plant secondary metabolites according to claim 1, characterized in that: The S6 specifically includes: S61, introducing the high-purity plant secondary metabolite solution obtained in step S5 into a liquid chromatography device for precise separation, wherein the liquid chromatography device uses a reverse phase chromatography column, wherein the pore size of the chromatography column is 2-5 μm, and the filler is C18 or a similar hydrophobic filler; S62, adjusting the mobile phase composition of the liquid chromatography, wherein the mobile phase is a mixture of water and an organic solvent, wherein the organic solvent is selected from acetonitrile, methanol, and acetone, and the proportion of the organic solvent in the mobile phase is 20-80%; S63, by adjusting the flow rate of liquid chromatography, the flow rate range is 0.5-2 mL / min, the separation of target plant secondary metabolites is achieved, and the flow rate is related to the retention time of the target product. The relationship between: ; in, The retention time of the target plant secondary metabolite refers to the time it takes for the target compound to pass through the chromatographic column in liquid chromatography. L represents the physical length of the chromatographic column. v flow rate refers to the flow rate of the mobile phase in liquid chromatography. Indicates the affinity of the target plant secondary metabolite between the liquid phase and the stationary phase. It is used to regulate the interaction between solvent and plant secondary metabolites. [Solvent] solvent concentration refers to the concentration of mobile phase solvent in liquid chromatography. It means that different solute concentrations will affect the retention time and distribution coefficient of the target component. [Solute] means the concentration of plant secondary metabolites or target compounds in the mobile phase. Indicates the effect of temperature on the distribution coefficient and retention time. [Temp] refers to the temperature during liquid chromatography operation. S64, set the temperature of the liquid chromatography to 20-50°C to separate and purify the plant secondary metabolites: ; in, is the change of chromatographic partition coefficient, is the column temperature; S65. Use appropriate detectors, such as UV-visible spectrometers, to monitor the concentration changes of each component during the separation process in real time, detect the purity of the target plant secondary metabolites, and the sensitivity of the detector. for: ; in, It represents the responsiveness of the chromatographic detector to the concentration change of the target plant secondary metabolite. I represents the signal intensity received by the detector, which is usually proportional to the concentration and reactivity of the target component. C represents the concentration of the target plant secondary metabolite in the solution. It indicates the influence of the composition and polarity of the solvent on the sensitivity of the chromatographic detector. [Solvent] indicates the concentration of the mobile phase solvent. represents the effect of the concentration of the target component on the sensitivity, [Solute] represents the concentration of the target plant secondary metabolite, It indicates the effect of temperature change on sensitivity, [Temp] indicates the operating temperature during the chromatography process; S66. After completing the liquid chromatography separation, the target plant secondary metabolites are collected to obtain a high-purity plant secondary metabolite solution. The purity of the solution is : ; in, is the purity of plant secondary metabolites, is the quality of target plant secondary metabolites, is the total mass of the solution after chromatographic separation.

8. The method for extracting poorly soluble plant secondary metabolites according to claim 1, characterized in that: The S7 specifically includes: S71, drying the high-purity plant secondary metabolite solution obtained in step S6, wherein the drying method is spray drying, freeze drying or vacuum drying, wherein the inlet air temperature of the spray drying is 150-250° C., and the outlet air temperature is 50-80° C.; S72. During the spray drying process, the flow rate and spray pressure of the solution are controlled. The spray pressure range is 1-3 MPa and the spray flow rate is 5-20 mL / min, so that the high-purity plant secondary metabolites are dried evenly. S73. When freeze drying is used, the plant secondary metabolite solution is pre-frozen to -20 to -80°C and gradually heated up under low pressure for sublimation. S74, vacuum drying is adopted, the vacuum degree is controlled at 10-100 Pa, the drying temperature is controlled at 40-70°C, moisture is removed, and the activity of plant secondary metabolites is maintained; S75. During the drying process, real-time monitoring of drying temperature, humidity and pressure is performed to reduce the loss of plant secondary metabolites; S76, after the drying is completed, collect the obtained dry powder; S77. Package and store the dried high-purity plant secondary metabolite powder.

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