Preparation method of olive leaf extract and olive leaf extract

Abstract

The invention provides a preparation method of an olive leaf extract and the olive leaf extract. Cellulase, pectinase and hemicellulase are used for carrying out enzymolysis treatment on olive leaves, modified 1-butyl-3-methylimidazolium hexafluorophosphate is combined as a cosolvent, and a supercritical CO2 extraction technology is utilized, so that the extraction rate and the purity of the extract are remarkably improved. The extraction rate of the method reaches 28.6% and is remarkably improved compared with that of a traditional method. The modified ionic liquid enhances the dissolving capacity of supercritical CO2, and the purity of the extract is higher. The method disclosed by the invention has the advantages of high extraction efficiency, high extract purity, good process stability and environmental friendliness, and is suitable for industrial production of the olive leaf extract.

Description

Technical Field

[0001] The invention relates to the technical field of mannose, and in particular to a preparation method of mannose based on extracting birch. Background Art

[0002] Olive leaf extract has been widely used in medicine, health products and cosmetics in recent years due to its rich polyphenol compounds, flavonoids and other bioactive ingredients. Traditional olive leaf extraction methods mainly include solvent extraction, distillation, water extraction and supercritical fluid extraction. Supercritical CO2 extraction technology, as a green, environmentally friendly and efficient extraction method, has been widely used in the field of plant extracts. This technology uses CO2 in a supercritical state, which has the characteristics of high density, low viscosity and high diffusion coefficient, and can efficiently dissolve and extract active ingredients in plants. However, the cell wall structure in olive leaves is complex, and the traditional supercritical CO2 extraction technology is often limited in the face of this structure. The extraction efficiency and purity of active ingredients are often limited. To this end, the combination of enzymatic hydrolysis technology and supercritical CO2 extraction technology has become an effective strategy to improve the extraction efficiency and purity of olive leaf extract.

[0003] Enzymolysis technology utilizes specific enzymes (such as cellulase, pectinase, etc.) to decompose plant cell walls, so that active ingredients can be released, and has achieved remarkable results in the preparation of plant extracts. Enzymolysis can effectively destroy the cell wall structure of olive leaves, improve the release efficiency of active ingredients, and provide more favorable conditions for subsequent supercritical CO2 extraction. However, in the prior art, there are still some shortcomings in the extraction efficiency and extract purity of enzymolysis or supercritical CO2 extraction alone. During the enzymolysis process, the type, concentration, reaction time and conditions of the enzyme have a significant impact on the extraction effect, and the residual enzymes and by-products in the enzymolysis solution may affect the subsequent extraction. And in the supercritical CO2 extraction process, the extraction pressure, temperature, time and other parameters also have an important impact on the extraction efficiency and purity. Therefore, combining enzymolysis and supercritical CO2 extraction technology, by optimizing the parameter settings of each link, the efficient extraction of active ingredients in olive leaves is achieved, which has important research significance and application value. Summary of the invention

[0004] In the prior art, there are still some deficiencies in the extraction efficiency and purity of the extracts when using enzymatic hydrolysis or supercritical CO2 extraction alone. During the enzymatic hydrolysis process, the type, concentration, reaction time and conditions of the enzyme have a significant impact on the extraction effect, and the residual enzymes and by-products in the enzymatic hydrolyzate may affect the subsequent extraction. In the supercritical CO2 extraction process, parameters such as extraction pressure, temperature, and time also have an important influence on the extraction efficiency and purity. Therefore, combining enzymatic hydrolysis and supercritical CO2 extraction technology, by optimizing the parameter settings of each link, to achieve efficient extraction of active ingredients in olive leaves, has important research significance and application value.

[0005] The present application provides a method for preparing olive leaf extract, comprising the following specific steps:

[0006] The first step is to clean and dry the olive leaves and crush them into 100-200 meshes;

[0007] The second step is to prepare cellulase, pectinase and hemicellulase solutions, mix the crushed olive leaves with the enzyme solution at a ratio of 1:10 (w / v), control the reaction temperature between 45°C and 55°C, and the pH value between 4.5 and 6.0, and perform enzymolysis reaction for 1 to 3 hours;

[0008] The third step is to place the olive leaf residue after enzymatic hydrolysis in a supercritical CO2 extraction device and add a co-solvent at a concentration of 5wt%-10wt%;

[0009] In the fourth step, after the extraction is completed, CO2 is removed by evaporation under reduced pressure, and the extract is subjected to ultrafiltration to remove solid residues and ionic liquid;

[0010] The fifth step is to use a chromatography column to purify the target active ingredient in the extract to obtain olive leaf extract.

[0011] By adopting the above technical scheme, crushing to 100-200 mesh can increase the specific surface area of ​​olive leaves, promote effective contact during enzymolysis and extraction, and improve extraction efficiency. Enzymolysis reaction can effectively degrade cellulose, pectin and hemicellulose in olive leaves, destroy cell wall structure, and release active ingredients in cells. Cellulase mainly acts on cellulose, pectinase acts on pectin, and hemicellulase acts on hemicellulose. The synergistic effect of these enzymes can significantly improve the release efficiency of active ingredients in olive leaves. Adding a cosolvent (such as modified 1-butyl-3-methylimidazolium hexafluorophosphate) with a concentration of 5wt%-10wt% can significantly improve the solubility of supercritical CO2 for polar compounds and enhance extraction efficiency. The introduction of cosolvents can change the solvent environment, improve the solubility and selectivity of target compounds, and thus optimize the extraction effect.

[0012] As a preferred technical solution for the preparation of olive leaf extract, in the second step, the cellulase concentration is 0.1wt%-0.5wt%, the pectinase concentration is 0.2wt%-0.6wt%, and the hemicellulase concentration is 0.1wt%-0.3wt%.

[0013] It should be noted that the above technical solution optimizes the concentration of each enzyme in the configured enzyme solution; in the process of olive leaf extraction, the combined use of cellulase, pectinase and hemicellulase can significantly improve the extraction efficiency. The concentration of cellulase is 0.1wt%-0.5wt%, and its main mechanism of action is to degrade cellulose in the cell wall of olive leaves, hydrolyze β-1,4-glucosidic bonds, and degrade cellulose into soluble oligosaccharides and glucose. Through the action of cellulase, the cellulose in the olive leaves is effectively decomposed, the cell wall structure is destroyed, and active ingredients such as polyphenols and flavonoids in the cells are released; the concentration of pectinase is 0.2wt%-0.6wt%, which mainly acts on pectin in the plant cell wall, hydrolyzes α-1,4-polygalacturonic acid chains, and decomposes pectin into galacturonic acid monomers or oligosaccharides. The action of pectinase can The pectin in the cell wall is degraded, and the cell wall is further softened and destroyed, so that more active ingredients can be released from the cell; the concentration of hemicellulase is 0.1wt%-0.3wt%, which acts on hemicellulose in the cell wall, such as xylan, arabinoxylan, etc., hydrolyzes these polysaccharides, and decomposes them into monosaccharides or oligosaccharides. Through the action of hemicellulase, hemicellulose is effectively degraded, further destroying the supporting structure of the cell wall and promoting the release of active ingredients in the cell; the synergistic action of the three enzymes can completely destroy the structure of the olive leaf cell wall, each acting on a different polysaccharide component to decompose cellulose, pectin and hemicellulose. Cellulase degrades cellulose, pectinase degrades pectin, and hemicellulase degrades hemicellulose. Through the synergistic action of the three enzymes, the cell wall can be destroyed to the maximum extent and the target active ingredients in the cell can be released.

[0014] As a preferred technical solution for the preparation of olive leaf extract, in the third step, the extraction pressure is set between 20-30 MPa, the extraction temperature is set between 35-45°C, the extraction time is set between 60-120 minutes, and the CO2 flow rate is set at 5-10 L / min.

[0015] It should be noted that by setting the extraction pressure at 20-30MPa, the extraction temperature at 35-45°C, the extraction time at 60-120 minutes, and the CO2 flow rate at 5-10L / min, the supercritical CO2 extraction process can be optimized to ensure the efficient extraction of the target active ingredients in the olive leaves. The comprehensive setting of these parameters can maximize the extraction efficiency and the purity of the extract while maintaining the integrity and stability of the active ingredients. Combined with the early enzymatic treatment and subsequent ultrafiltration and column chromatography purification, high-quality olive leaf extract can be obtained.

[0016] As a preferred technical solution for the preparation of olive leaf extract, the co-solvent is modified 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], and the preparation method comprises: adding [BMIM][PF6] and ethylenediamine in a dry three-necked flask, wherein the mass ratio of [BMIM][PF6] to ethylenediamine is 1:2, adding an appropriate amount of anhydrous ethanol as a solvent, stirring the mixture under nitrogen protection and heating to 50° C., reacting for 12 hours, and cooling to room temperature after the reaction is completed to obtain 1-(2-aminoethyl)-3-methylimidazolium hexafluorophosphate ([BMIM-CH2CH2NH2][PF6], and then removing the solvent by reduced pressure evaporation to purify the product.

[0017] By adopting the above technical scheme, the modified 1-(2-aminoethyl)-3-methylimidazolium hexafluorophosphate ([BMIM-CH2CH2NH2][PF6]) as a co-solvent has significant advantages in the olive leaf extraction process. First, the introduced aminoethyl group enhances the polarity and hydrogen bond forming ability of the ionic liquid. This structural modification enables [BMIM-CH2CH2NH2][PF6] to more effectively dissolve polar compounds, especially polyphenols and flavonoids in olive leaves, thereby improving the extraction efficiency. Secondly, the presence of the aminoethyl group can form a stronger interaction with the enzyme molecule, stabilize the conformation of the enzyme, and improve the catalytic activity and stability of the enzyme. The modified ionic liquid can provide a more suitable microenvironment for the enzyme, enhance the catalytic performance of the enzyme, and improve the enzymatic efficiency.

[0018] By introducing aminoethyl groups into modified 1-butyl-3-methylimidazolium hexafluorophosphate, a co-solvent with higher solubility and enzymatic reaction stability was successfully prepared, which not only significantly improved the extraction efficiency and purity of olive leaf extract, but also enhanced the activity and stability of the enzyme, optimizing the overall effect of the extraction process.

[0019] As a preferred technical solution for the preparation of olive leaf extract, the fourth step comprises the following specific steps:

[0020] Transfer the mixture after extraction to a reduced pressure evaporation device, heat the evaporator to 30-40°C, start the vacuum pump, and gradually reduce the pressure in the system to 10-30KPa;

[0021] The extract after reduced pressure evaporation is cooled to room temperature, filtered through filter paper to remove large particles of solid matter, the ultrafiltration membrane is installed in the ultrafiltration device, the pump and pipeline are connected to ensure that the system is leak-free, the cooled extract is slowly introduced into the ultrafiltration device, the operating pressure of the ultrafiltration device is set to 1 to 5 bar, the feed flow rate is controlled to 0.1-1L / min, the ultrafiltration device is started, and the extract is circulated in the ultrafiltration membrane. The filtrate is collected in the filtrate container, which contains the extract of the target active ingredient, and the retentate is collected in the retentate container, which contains solid residue and ionic liquid.

[0022] It should be noted that the design and operation of the above steps ensure the efficient removal of the solvent CO2 and the preliminary purification of the extract after the extraction is completed. The large solid particles are removed by reduced pressure evaporation and filter paper filtration, laying the foundation for the subsequent ultrafiltration treatment. The fine filtration during the ultrafiltration process further removes the solid residue and ionic liquid in the extract and improves the purity of the extract. Through a series of optimized operations, the high efficiency of the extraction process and the high quality of the extract are achieved, providing a reliable foundation for subsequent purification and application. This series of processing steps fully utilizes the advantages of reduced pressure evaporation and ultrafiltration technology, ensures the stability and efficiency of the extraction process, and significantly improves the purity and quality of the extract.

[0023] The preparation method of the olive leaf extract and the olive leaf extract of the present application significantly improve the extraction rate and the purity of the extract by optimizing the enzymatic hydrolysis conditions and using modified 1-butyl-3-methylimidazolium hexafluorophosphate as a co-solvent. The specific beneficial effects are as follows:

[0024] The extraction rate is significantly improved: through the synergistic action of cellulase, pectinase and hemicellulase, the olive leaf cell wall can be efficiently degraded, releasing more active ingredients, and the extraction rate reaches 28.6%;

[0025] Improved purity of extracts: Using modified 1-butyl-3-methylimidazolium hexafluorophosphate as a co-solvent enhances the solubility of supercritical CO2 extraction and improves the purity of the extracts;

[0026] Good process stability: The modified ionic liquid not only improves the extraction efficiency, but also exhibits good chemical stability and thermal stability during enzymatic hydrolysis and extraction, ensuring the stability and repeatability of the process;

[0027] Environmentally friendly: This method uses green solvent supercritical CO2, which avoids the problem of organic solvent residue and has the advantages of environmental protection and safety. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0030] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0031] Preparation Example 1

[0032] Preparation of 1-(2-aminoethyl)-3-methylimidazolium hexafluorophosphate

[0033] In a dry three-necked flask, [BMIM][PF6] and ethylenediamine were added in a mass ratio of [BMIM][PF6] to ethylenediamine of 1:2. An appropriate amount of anhydrous ethanol was added as a solvent. Under nitrogen protection, the mixture was stirred and heated to 50°C for 12 hours. After the reaction was completed, it was cooled to room temperature to obtain 1-(2-aminoethyl)-3-methylimidazolium hexafluorophosphate ([BMIM-CH2CH2NH2][PF6]). The solvent was then removed by reduced pressure evaporation to purify the product.

[0034] Example 1

[0035] A method for preparing olive leaf extract comprises the following specific steps:

[0036] The first step is to clean and dry the olive leaves and crush them to 200 mesh;

[0037] The second step is to prepare cellulase, pectinase and hemicellulase solutions, wherein the cellulase concentration is 0.1wt%, the pectinase concentration is 0.4wt%, and the hemicellulase concentration is 0.3wt%, and the crushed olive leaves are mixed with the enzyme solution at a ratio of 1:10 (w / v), the reaction temperature is controlled at 55°C, the pH value is 4.5, and the enzymolysis reaction is carried out for 3 hours;

[0038] The third step is to place the olive leaf residue after enzymatic hydrolysis in a supercritical CO2 extraction device, add the co-solvent prepared in Preparation Example 1 at a concentration of 10wt%, set the extraction pressure between 30MPa, the extraction temperature between 45°C, the extraction time for 100 minutes, and the CO2 flow rate at 10L / min;

[0039] Step 4: Transfer the mixture after extraction to a reduced pressure evaporation device, heat the evaporator to 40°C, start the vacuum pump, and gradually reduce the pressure in the system to 30KPa;

[0040] The extract after reduced pressure evaporation is cooled to room temperature, filtered through filter paper to remove large particles of solid matter, the ultrafiltration membrane is installed in the ultrafiltration device, the pump and pipeline are connected to ensure that the system is leak-free, the cooled extract is slowly introduced into the ultrafiltration device, the operating pressure of the ultrafiltration device is set to 5 bar, the feed flow rate is controlled to 0.1 L / min, the ultrafiltration device is started, and the extract is circulated in the ultrafiltration membrane, the filtrate is collected in the filtrate container, and the extract contains the target active ingredient, and the retentate is collected in the retentate container, and the solid residue and ionic liquid are contained;

[0041] The fifth step is to use a chromatography column to purify the target active ingredient in the extract to obtain olive leaf extract.

[0042] Example 2

[0043] A method for preparing olive leaf extract comprises the following specific steps:

[0044] The first step is to clean and dry the olive leaves and crush them into 150 meshes;

[0045] The second step is to prepare cellulase, pectinase and hemicellulase solutions, wherein the cellulase concentration is 0.5wt%, the pectinase concentration is 0.2wt%, and the hemicellulase concentration is 0.1wt%, and the crushed olive leaves are mixed with the enzyme solution at a ratio of 1:10 (w / v), the reaction temperature is controlled at 45°C, the pH value is 6.0, and the enzymolysis reaction is carried out for 3 hours;

[0046] The third step is to place the olive leaf residue after enzymatic hydrolysis in a supercritical CO2 extraction device, add the co-solvent prepared in Preparation Example 1 at a concentration of 5wt%, set the extraction pressure between 20MPa, the extraction temperature between 40°C, the extraction time for 120 minutes, and the CO2 flow rate at 5L / min;

[0047] Step 4: Transfer the mixture after extraction to a reduced pressure evaporation device, heat the evaporator to 30°C, start the vacuum pump, and gradually reduce the pressure in the system to 10KPa;

[0048] The extract after reduced pressure evaporation is cooled to room temperature, filtered through filter paper to remove large particles of solid matter, the ultrafiltration membrane is installed in the ultrafiltration device, the pump and pipeline are connected to ensure that the system is leak-free, the cooled extract is slowly introduced into the ultrafiltration device, the operating pressure of the ultrafiltration device is set to 1 bar, the feed flow rate is controlled to 1L / min, the ultrafiltration device is started, and the extract is circulated in the ultrafiltration membrane, the filtrate is collected in the filtrate container, and the extract contains the target active ingredient, and the retentate is collected in the retentate container, and the solid residue and ionic liquid are contained;

[0049] The fifth step is to use a chromatography column to purify the target active ingredient in the extract to obtain olive leaf extract.

[0050] Example 3

[0051] A method for preparing olive leaf extract comprises the following specific steps:

[0052] The first step is to clean and dry the olive leaves and crush them into 100 meshes;

[0053] The second step is to prepare cellulase, pectinase and hemicellulase solutions, wherein the cellulase concentration is 0.3wt%, the pectinase concentration is 0.6wt%, and the hemicellulase concentration is 0.1wt%, and the crushed olive leaves are mixed with the enzyme solution at a ratio of 1:10 (w / v), and the reaction temperature is controlled at 35°C and the pH value is 5.0, and the enzymolysis reaction is carried out for 1 hour;

[0054] The third step is to place the olive leaf residue after enzymatic hydrolysis in a supercritical CO2 extraction device, add the co-solvent prepared in Preparation Example 1 at a concentration of 8 wt%, set the extraction pressure between 25 MPa, the extraction temperature between 35 ° C, the extraction time for 60 minutes, and the CO2 flow rate of 8 L / min;

[0055] Step 4: Transfer the mixture after extraction to a reduced pressure evaporation device, heat the evaporator to 30°C, start the vacuum pump, and gradually reduce the pressure in the system to 30KPa;

[0056] The extract after reduced pressure evaporation is cooled to room temperature, filtered through filter paper to remove large particles of solid matter, the ultrafiltration membrane is installed in the ultrafiltration device, the pump and pipeline are connected to ensure that the system is leak-free, the cooled extract is slowly introduced into the ultrafiltration device, the operating pressure of the ultrafiltration device is set to 4 bar, the feed flow rate is controlled to 0.8 L / min, the ultrafiltration device is started, and the extract is circulated in the ultrafiltration membrane, the filtrate is collected in the filtrate container, and the extract contains the target active ingredient, and the retentate is collected in the retentate container, and the solid residue and ionic liquid are contained;

[0057] The fifth step is to use a chromatography column to purify the target active ingredient in the extract to obtain olive leaf extract.

[0058] Comparative Example 1

[0059] The difference between this comparative example and Example 1 is that the co-solvent in the third step is replaced by an equal amount of ethanol.

[0060] Comparative Example 2

[0061] The difference between this comparative example and Example 1 is that the co-solvent in the third step is replaced by an equal amount of unmodified 1-butyl-3-methylimidazolium hexafluorophosphate.

[0062] Comparative Example 3

[0063] This comparative example differs from Example 1 in that only cellulase was used.

[0064] Comparative Example 4

[0065] This comparative example differs from Example 1 in that only pectinase was used.

[0066] Comparative Example 5

[0067] This comparative example differs from Example 1 in that only hemicellulase was used.

[0068] Comparative Example 6

[0069] The difference between this comparative example and Example 1 is that a mixed solution of cellulase and pectinase is used.

[0070] Comparative Example 7

[0071] The difference between this comparative example and Example 1 is that a mixed solution of pectinase and hemicellulase is used.

[0072] Comparative Example 8

[0073] The difference between this comparative example and Example 1 is that a mixed solution of cellulase and hemicellulase is used.

[0074] The extraction rates of the extracts in the test examples and comparative examples are shown in Table 1 below.

[0075] Table 1

[0076]

[0077]

[0078] Combining Examples 1 to 3 and Table 1, it can be seen that the extraction rates of Example 1, Example 2 and Example 3 are 28.6%, 27.9% and 26.8% respectively. Compared with Comparative Examples 1 and 2, the extraction rates of these Examples are significantly improved.

[0079] It can be seen from Example 1, Comparative Example 1, Comparative Example 2 and Table 1 that the introduction of modified 1-butyl-3-methylimidazole hexafluorophosphate significantly improves the extraction rate of olive leaf extract, and the optimization of enzymatic hydrolysis and supercritical CO2 extraction processes, through the fine control of enzyme type, concentration, reaction time and temperature, can maximize the destruction of cell wall structure and improve the release and extraction efficiency of active ingredients.

[0080] Combining Example 1, Comparative Examples 3 to 8 and Table 1, it can be seen that the extraction rates of Example 1, Comparative Examples 3 to 8 are 28.6%, 15.6%, 16.8%, 18.9%, 19.8%, 20.7% and 21.5%, respectively, from which it can be seen that Example 1 significantly improves the extraction rate by optimizing the enzymatic hydrolysis and supercritical CO2 extraction process. The extraction rates of Comparative Examples 3 to 8 are significantly lower than those of Example 1, further demonstrating the effectiveness of multi-enzyme synergy and modified ionic liquids.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing olive leaf extract, It is characterized in that The specific steps include: The first step is to clean and dry the olive leaves and crush them into 100-200 meshes; The second step is to prepare cellulase, pectinase and hemicellulase solutions, mix the crushed olive leaves with the enzyme solution at a ratio of 1:10 (w / v), control the reaction temperature between 45°C and 55°C, and the pH value between 4.5 and 6.0, and perform enzymolysis reaction for 1 to 3 hours; In the third step, the enzymatically hydrolyzed olive leaf residue was placed in a supercritical CO 2 In the extraction device, a co-solvent is added at a concentration of 5wt%-10wt%; Step 4: After the extraction, remove CO by evaporation under reduced pressure 2 , subjecting the extract to ultrafiltration treatment to remove solid residues and ionic liquid; The fifth step is to use a chromatography column to purify the target active ingredient in the extract to obtain olive leaf extract.

2. The method for preparing the olive leaf extract according to claim 1, It is characterized in that In the second step, the concentration of the cellulase is 0.1 wt%-0.5 wt%, the concentration of the pectinase is 0.2 wt%-0.6 wt%, and the concentration of the hemicellulase is 0.1 wt%-0.3 wt%.

3. The method for preparing the olive leaf extract according to claim 1, It is characterized in that In the third step, the extraction pressure is set between 20-30 MPa, the extraction temperature is set between 35-45 °C, the extraction time is set between 60-120 minutes, and the CO 2 The flow rate is 5-10L / min.

4. The method for preparing the olive leaf extract according to claim 1, It is characterized in that The co-solvent is modified 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM] [PF 6 ].

5. The method for preparing the olive leaf extract according to claim 4, It is characterized in that The modified 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM] [PF 6 The preparation method of ] comprises: adding [BMIM][PF 6 ] and ethylenediamine, [BMIM][PF 6 The mass ratio of ] and ethylenediamine was 1:2, and an appropriate amount of anhydrous ethanol was added as a solvent. Under nitrogen protection, the mixture was stirred and heated to 50°C for 12 hours. After the reaction was completed, it was cooled to room temperature to obtain 1-(2-aminoethyl)-3-methylimidazolium hexafluorophosphate ([BMIM-CH 2 CH 2 NH 2 ][PF 6 ], and then the solvent was removed by evaporation under reduced pressure to purify the product.

6. The method for preparing the olive leaf extract according to claim 1, It is characterized in that The fourth step includes the following specific steps: Transfer the mixture after extraction to a reduced pressure evaporation device, heat the evaporator to 30-40°C, start the vacuum pump, and gradually reduce the pressure in the system to 10-30KPa; The extract after reduced pressure evaporation is cooled to room temperature, filtered through filter paper to remove large particles of solid matter, the ultrafiltration membrane is installed in the ultrafiltration device, the pump and pipeline are connected to ensure that the system is leak-free, the cooled extract is slowly introduced into the ultrafiltration device, the operating pressure of the ultrafiltration device is set to 1 to 5 bar, the feed flow rate is controlled to 0.1-1L / min, the ultrafiltration device is started, and the extract is circulated in the ultrafiltration membrane. The filtrate is collected in the filtrate container, which contains the extract of the target active ingredient, and the retentate is collected in the retentate container, which contains solid residue and ionic liquid.

7. Extracting olive leaf extract based on the preparation method according to any one of claims 1 to 6.

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