Method for extracting chlorogenic acid from honeysuckle

Abstract

The invention relates to the technical field of separation and extraction, and provides a method for extracting chlorogenic acid from honeysuckle. The method for extracting chlorogenic acid from honeysuckle comprises the following steps: drying and crushing honeysuckle to obtain honeysuckle powder, mixing the honeysuckle powder with a citric acid-disodium hydrogen phosphate buffer solution, and adding a compound enzyme for enzymolysis; adding an ethanol aqueous solution into the enzymatic hydrolysate, performing ultrasonic mixing, and then performing extraction; after the extraction is completed, cooling to room temperature, carrying out suction filtration to obtain a supernatant containing chlorogenic acid and medicine residues, mixing the medicine residues with a monopotassium phosphate solution, adding a Fe3O4-coated CQD nano catalyst, carrying out a hydrothermal reaction, recovering the catalyst, and merging an obtained liquid-phase product containing a chlorogenic acid precursor compound into the supernatant to obtain an extraction solution; performing vacuum concentration on the extraction liquid; and further concentrating the concentrated solution under reduced pressure to form thick paste, and performing spray drying to obtain the chlorogenic acid extract. According to the method for extracting chlorogenic acid from honeysuckle, provided by the invention, the extraction efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of separation and extraction, and in particular to a method for extracting chlorogenic acid from honeysuckle. Background Art

[0002] Chlorogenic acid is a phenylpropanoid compound formed by the condensation of caffeic acid and quinic acid. It is widely found in plants of the Caprifoliaceae, Asteraceae, and Eucommiaceae families. Studies have shown that chlorogenic acid has significant activity in inhibiting tumor cell proliferation, regulating blood sugar metabolism, and anti-inflammatory effects. It is one of the main active ingredients in traditional Chinese medicines such as honeysuckle. With the advancement of modern separation technology, the demand for the application of chlorogenic acid in functional foods, natural preservatives, and pharmaceutical preparations continues to grow. However, due to technical limitations, existing extraction processes are difficult to meet the efficiency, purity, and environmental protection requirements of industrial production. There is an urgent need to develop efficient and low-cost extraction technologies.

[0003] Currently, a common method for extracting chlorogenic acid from honeysuckle is ethanol reflux extraction. The basic principle of this method is to use ethanol as a solvent and reflux extract the honeysuckle at a certain temperature to dissolve the chlorogenic acid from the plant tissue into the ethanol solution, and then obtain the chlorogenic acid product through subsequent separation and purification steps. Although the ethanol reflux extraction method can extract chlorogenic acid from honeysuckle, the extraction efficiency is affected by many factors, such as extraction temperature, time, ethanol concentration, etc. In actual operation, it is difficult to accurately control these parameters to achieve the best extraction effect. Moreover, this method is often not thorough enough to extract chlorogenic acid from honeysuckle, resulting in some chlorogenic acid remaining in the medicinal residue, resulting in a waste of resources. In addition, chlorogenic acid may undergo certain degradation or transformation during the extraction process, further reducing the extraction efficiency. Based on this, the present invention proposes a method for extracting chlorogenic acid from honeysuckle. Summary of the Invention

[0004] The present invention provides a method for extracting chlorogenic acid from honeysuckle, which improves the extraction efficiency and yield of chlorogenic acid from honeysuckle.

[0005] The technical solutions of the present invention are as follows: The present invention provides a method for extracting chlorogenic acid from honeysuckle, comprising the following steps: (1) The honeysuckle powder obtained by drying and crushing the honeysuckle is mixed with citric acid-disodium hydrogen phosphate buffer, and a complex enzyme is added for enzymatic hydrolysis; (2) Adding ethanol aqueous solution to the enzymatic hydrolyzate, ultrasonically mixing, and then extracting; (3) After the extraction is completed, the mixture is cooled to room temperature and filtered to obtain a supernatant containing chlorogenic acid and a drug residue. The drug residue is mixed with a potassium dihydrogen phosphate solution, and a Fe3O4@CQD nanocatalyst is added. After a hydrothermal reaction, the catalyst is recovered and the liquid product containing the chlorogenic acid precursor compound is added to the supernatant to obtain an extract. (4) Concentrate the extract under reduced pressure and recover ethanol until the volume of the concentrate is approximately 1 / 5-1 / 10 of the original volume; (5) The concentrate is further concentrated under reduced pressure to a thick paste, and spray-dried to obtain the chlorogenic acid extract.

[0006] As a further technical solution, the pH of the citric acid-disodium hydrogen phosphate buffer solution is 4.5-5.5, and the solid-liquid ratio of honeysuckle pollen to citric acid-disodium hydrogen phosphate buffer solution is 1g:15-25mL.

[0007] As a further technical solution, the complex enzyme includes cellulase and pectinase in a weight ratio of 1:1-2, and the added amount of the complex enzyme is 1.0%-2.0% of the dry weight of honeysuckle pollen; the enzymatic hydrolysis is constant temperature oscillation enzymatic hydrolysis at 45-55°C for 60-90 minutes.

[0008] As a further technical solution, the volume fraction of ethanol in the ethanol aqueous solution is 30%-50%, and after the ethanol aqueous solution is added in step (2), the solid-liquid ratio is adjusted to 1g:20-30mL.

[0009] As a further technical solution, in step (2), the ultrasonic temperature is 40-50°C, the ultrasonic power is 200-400W, the ultrasonic frequency is 20-40kHz, and the ultrasonic time is 20-40min.

[0010] As a further technical solution, the potassium dihydrogen phosphate solution is a 0.4-0.6 mol / L potassium dihydrogen phosphate aqueous solution, and the weight ratio of the medicinal residue, potassium dihydrogen phosphate solution and Fe3O4@CQD nanocatalyst is 1g:10-12mL:0.05-0.07g.

[0011] As a further technical solution, the preparation method of the Fe3O4@CQD nanocatalyst includes: dissolving citric acid and urea in water, conducting a hydrothermal reaction at a temperature of 180-220°C for 4-6 hours, cooling and dialysis purification to obtain a CQD solution; resuspending the Fe3O4 magnetic core in the CQD solution, ultrasonically dispersing it, and then hydrothermally reacting it at a temperature of 160-180°C for 8-12 hours, separating and drying it to obtain the product.

[0012] As a further technical solution, the preparation method of the Fe3O4 magnetic core includes: dissolving FeCl3·6H2O and FeCl2·4H2O in nitrogen-deoxygenated deionized water with a total iron ion concentration of 0.1-0.3 mol / L, adding ammonia water dropwise to a pH of 9.0-11.0 under nitrogen protection and mechanical stirring at 300-500 rpm, carrying out a co-precipitation reaction at a temperature of 50-70°C for 30-60 minutes, collecting the precipitate by magnetic separation, and washing with deoxygenated water until neutral to obtain the obtained product.

[0013] As a further technical solution, the weight ratio of the Fe3O4 magnetic core to the CQD in the CQD solution is 1:0.2-0.5.

[0014] As a further technical solution, the temperature of the hydrothermal reaction in step (3) is 170-190°C and the time is 2-3 hours; the spray drying in step (5) adopts a low-pressure freeze-spray drying combined technology, the concentrated liquid is pre-cooled to -20°C~-30°C to form ice particles, and is instantaneously sublimated and dried with 115-125°C hot air in a low-pressure environment of 0.01-0.02MPa, and the discharge temperature is ≤45°C.

[0015] The working principle and beneficial effects of the present invention are: This invention combines enzymatic hydrolysis with ultrasound technology to extract chlorogenic acid from honeysuckle. Honeysuckle cell walls are primarily composed of cellulose, pectin, and other components, which form a physical barrier that hinders the effective dissolution of chlorogenic acid within the cells. A complex enzyme (cellulase and pectinase) specifically targets and degrades the cellulose and pectin structures within the cell wall, thereby disrupting the integrity of the cell wall and increasing the permeability of the cell membrane, allowing for smoother release of chlorogenic acid into the extraction system. The cavitation effect generated by ultrasound creates a localized high-temperature and high-pressure environment in the liquid, generating intense shock waves and microjets. This physical action further disrupts the cell wall and cell membrane, allowing for more complete dissolution of intracellular substances. Ultrasound also promotes mixing and mass transfer between the solvent and the material, improving extraction efficiency. The synergistic effect of enzymes and ultrasound disrupts the cell wall structure at different levels, enhancing the dissolution of chlorogenic acid. This allows for more efficient extraction of chlorogenic acid from honeysuckle compared to single methods.

[0016] In this invention, the extracted medicinal residue is further treated by a hydrothermal reaction using potassium dihydrogen phosphate solution and Fe3O4@CQD nanocatalysts to recover chlorogenic acid precursor compounds from the residue. Chlorogenic acid may exist in various forms in honeysuckle. In addition to directly extractable chlorogenic acid, some chlorogenic acid precursor compounds are also present. These precursor compounds may not be fully converted to chlorogenic acid during conventional extraction processes and may be extracted, remaining in the medicinal residue. The Fe3O4@CQD nanocatalyst has unique structure and properties. CQDs (carbon quantum dots) have abundant surface functional groups and acidic sites, providing active centers for the reaction and promoting the conversion of chlorogenic acid precursor compounds. The Fe3O4 magnetic cores impart excellent magnetic properties to the catalyst, facilitating its recovery and reuse. Under the suitable acid-base environment provided by the potassium dihydrogen phosphate solution, the Fe3O4@CQD nanocatalyst catalyzes the chemical reaction of chlorogenic acid precursor compounds in the medicinal residue, converting them into chlorogenic acid, thereby increasing the overall yield of chlorogenic acid and fully utilizing the raw material of honeysuckle.

[0017] The present invention adopts a low-pressure freeze-spray drying combined technology to pre-cool the concentrate to form ice particles, and then perform instantaneous sublimation drying under a low-pressure environment. Chlorogenic acid is a heat-sensitive substance that is prone to degradation reactions under high temperature conditions, generating by-products, thereby reducing the purity of chlorogenic acid. Traditional spray drying technology is usually carried out at a higher temperature, which will lead to thermal degradation of chlorogenic acid. The low-pressure freeze-spray drying combined technology first pre-cools the concentrate to a low temperature to form ice particles, and then in a low-pressure environment, hot air can quickly sublimate the water in the ice particles to achieve drying. This drying method avoids the damage to chlorogenic acid caused by high temperature, can remove water in a short time, retains the chemical structure and activity of chlorogenic acid to the greatest extent, and improves the purity of the chlorogenic acid product. At the same time, this technology can also effectively reduce energy consumption and time in the drying process, thereby improving production efficiency.

[0018] In the present invention, a Fe3O4@CQD nanocatalyst with a specific structure and performance is prepared and applied to the catalytic conversion step of medicinal residues. Citric acid and urea are converted into CQDs through a hydrothermal reaction. CQDs have a large specific surface area, rich surface functional groups and good optical properties. These properties enable CQDs to provide a large number of active sites, enhancing the catalytic activity of the catalyst. The Fe3O4 magnetic core not only provides magnetism to the catalyst, facilitating separation and recovery through a magnetic field, but also can affect the dispersibility and stability of the catalyst to a certain extent. The Fe3O4 magnetic core is resuspended in a CQD solution, and through ultrasonic dispersion and hydrothermal reaction, the CQDs can be uniformly loaded on the surface of the Fe3O4 magnetic core to form a Fe3O4@CQD nanocatalyst. This composite structure combines the catalytic activity of CQDs with the magnetism of Fe3O4, allowing the catalyst to function efficiently in the catalytic conversion reaction of medicinal residues, and can be easily recovered and reused after the reaction, reducing production costs and improving catalyst utilization. DETAILED DESCRIPTION

[0019] Below in conjunction with the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only a part of embodiment of the present invention, rather than whole embodiment.Based on the embodiment in the present invention, those of ordinary skill in the art, without making the every other embodiment obtained under creative work premise, all relate to the scope of protection of the present invention.It should be noted that, in the present invention, cellulase and pectinase used are all purchased from Shandong Long Ke Te Enzyme Preparation Co., Ltd.

[0020] Example 1 This embodiment provides a method for extracting chlorogenic acid from honeysuckle, comprising the following steps: (1) Honeysuckle was dried at 45°C to constant weight, crushed and sieved through a 50-mesh sieve to obtain honeysuckle pollen, which was mixed with a citric acid-disodium hydrogen phosphate buffer solution with a pH of 5. The solid-liquid ratio of honeysuckle pollen to citric acid-disodium hydrogen phosphate buffer solution was 1 g:20 mL. A complex enzyme of cellulase and pectinase with a weight ratio of 1:1.5 was added and the mixture was enzymolyzed at 50°C with constant temperature and oscillation for 75 min. The enzyme addition amount was 1.5% of the dry weight of the honeysuckle pollen. (2) Add 40% ethanol aqueous solution to the hydrolyzate to adjust the solid-liquid ratio to 1 g:25 mL. Ultrasonic mixing was performed at a temperature of 45 °C, a power of 300 W, and a frequency of 30 kHz for 30 min, followed by extraction. The ultrasonic method was ultrasonication for 2 s and rest for 2 s. (3) After the extraction is completed, the mixture is cooled to room temperature and filtered to obtain a supernatant containing chlorogenic acid and a drug residue. The drug residue is mixed with a 0.5 mol / L potassium dihydrogen phosphate aqueous solution, and Fe3O4@CQD nanocatalyst is added. The temperature is 180°C for hydrothermal reaction for 2.5 h, and the catalyst is recovered. The liquid product containing the chlorogenic acid precursor compound is added to the supernatant to obtain an extract. The weight ratio of the drug residue, potassium dihydrogen phosphate solution and Fe3O4@CQD nanocatalyst is 1 g:11 mL:0.06 g. (4) Concentrate the extract under reduced pressure at 45°C and recover ethanol until the volume of the concentrate is approximately 1 / 7 of the original volume; (5) The concentrate was further concentrated under reduced pressure at 45°C to a thick paste, and the concentrate was pre-cooled to -25°C to form ice particles. The concentrate was instantaneously sublimated and dried with 120°C hot air under a low pressure environment of 0.015 MPa, and the discharge temperature was 45°C to finally obtain the chlorogenic acid extract; The preparation method of the Fe3O4@CQD nanocatalyst includes: Citric acid and urea were dissolved in deionized water at a molar ratio of 1:4, with a solid-liquid ratio of 0.2 g / mL. The mixture was hydrothermally reacted at 200°C for 5 h. After cooling, the mixture was dialyzed and purified with a molecular weight cut-off of 1000 Da to obtain a 7 mg / mL CQD solution. FeCl3·6H2O and FeCl2·4H2O were dissolved in nitrogen-deoxygenated deionized water at a molar ratio of 1:0.6 to a total iron ion concentration of 0.2 mol / L. Under nitrogen protection and mechanical stirring at 400 rpm, ammonia water was added dropwise to a pH of 10.0. The mixture was co-precipitated at 60°C for 45 minutes. The precipitate was collected by magnetic separation and washed with deoxygenated water until neutral to obtain Fe3O4 magnetic cores. The Fe3O4 magnetic cores were resuspended in the CQD solution with a Fe3O4:CQD weight ratio of 1:0.35. Ultrasonic dispersion was performed at 40 kHz for 35 min. The solution was hydrothermally reacted at 170°C for 10 h. The product was separated by a magnetic field and dried in a vacuum at 60°C to constant weight.

[0021] Example 2 This embodiment provides a method for extracting chlorogenic acid from honeysuckle, comprising the following steps: (1) Honeysuckle was dried at 40°C to constant weight, crushed, and then passed through a 40-mesh sieve to obtain honeysuckle pollen, which was mixed with a citric acid-disodium hydrogen phosphate buffer solution with a pH of 4.5. The solid-liquid ratio of honeysuckle pollen to citric acid-disodium hydrogen phosphate buffer was 1 g:15 mL. A complex enzyme of cellulase and pectinase in a weight ratio of 1:1 was added and the mixture was subjected to constant temperature oscillation at 45°C for 60 min. The enzyme addition amount was 1.0% of the dry weight of the honeysuckle pollen. (2) Add 30% ethanol aqueous solution to the hydrolyzate to adjust the solid-liquid ratio to 1 g:20 mL. Ultrasonic mixing was performed at a temperature of 40 °C, a power of 200 W, and a frequency of 20 kHz for 20 min, followed by extraction. The ultrasonic method was ultrasonication for 2 s and rest for 2 s. (3) After the extraction is completed, the mixture is cooled to room temperature and filtered to obtain a supernatant containing chlorogenic acid and a drug residue. The drug residue is mixed with a 0.4 mol / L potassium dihydrogen phosphate aqueous solution, and Fe3O4@CQD nanocatalyst is added. The temperature is 170°C for hydrothermal reaction for 2 h, and the catalyst is recovered. The liquid product containing the chlorogenic acid precursor compound is added to the supernatant to obtain an extract. The weight ratio of the drug residue, potassium dihydrogen phosphate solution and Fe3O4@CQD nanocatalyst is 1 g:10 mL:0.05 g. (4) Concentrate the extract under reduced pressure at 40°C and recover ethanol until the volume of the concentrate is approximately 1 / 5 of the original volume; (5) The concentrate was further concentrated under reduced pressure at 40°C to a thick paste, and the concentrate was pre-cooled to -20°C to form ice particles. The concentrate was instantaneously sublimated and dried with hot air at 115°C under a low pressure environment of 0.01 MPa, and the discharge temperature was 45°C to finally obtain the chlorogenic acid extract; The preparation method of the Fe3O4@CQD nanocatalyst includes: Citric acid and urea were dissolved in deionized water at a molar ratio of 1:3.5, with a solid-liquid ratio of 0.1 g / mL. The mixture was hydrothermally reacted at 180°C for 4 h. After cooling, the mixture was dialyzed and purified with a molecular weight cut-off of 1000 Da to obtain a 5 mg / mL CQD solution. FeCl3·6H2O and FeCl2·4H2O were dissolved in nitrogen-deoxygenated deionized water at a molar ratio of 1:0.5, with a total iron ion concentration of 0.1 mol / L. Under nitrogen protection and mechanical stirring at 300 rpm, ammonia water was added dropwise to pH = 9.0. The mixture was co-precipitated at 50°C for 30 minutes. The precipitate was collected by magnetic separation and washed with deoxygenated water until neutral to obtain Fe3O4 magnetic cores. The Fe3O4 magnetic cores were resuspended in the CQD solution with a weight ratio of Fe3O4:CQD of 1:0.2. Ultrasonic dispersion was performed at 40kHz for 30min, and the solution was hydrothermally reacted at 160°C for 8h. The product was separated by a magnetic field and vacuum dried at 60°C to constant weight.

[0022] Example 3 This embodiment provides a method for extracting chlorogenic acid from honeysuckle, comprising the following steps: (1) Honeysuckle was dried at 50°C to constant weight, crushed, and then passed through a 60-mesh sieve to obtain honeysuckle pollen, which was mixed with a citric acid-disodium hydrogen phosphate buffer solution with a pH of 5.5. The solid-liquid ratio of honeysuckle pollen to citric acid-disodium hydrogen phosphate buffer was 1 g:25 mL. A complex enzyme of cellulase and pectinase in a weight ratio of 1:2 was added and the mixture was subjected to constant temperature oscillation at 55°C for 90 min. The enzyme addition amount was 2.0% of the dry weight of the honeysuckle pollen. (2) Add 50% ethanol aqueous solution to the hydrolyzate to adjust the solid-liquid ratio to 1 g:30 mL. Ultrasonic mixing was performed at a temperature of 50 °C, a power of 400 W, and a frequency of 40 kHz for 40 min, followed by extraction. The ultrasonic method was ultrasonication for 2 s and rest for 2 s. (3) After the extraction is completed, the mixture is cooled to room temperature and filtered to obtain a supernatant containing chlorogenic acid and a drug residue. The drug residue is mixed with a 0.6 mol / L potassium dihydrogen phosphate aqueous solution, and Fe3O4@CQD nanocatalyst is added. The temperature is 190°C for hydrothermal reaction for 3 h, and the catalyst is recovered. The liquid product containing the chlorogenic acid precursor compound is added to the supernatant to obtain an extract. The weight ratio of the drug residue, potassium dihydrogen phosphate solution and Fe3O4@CQD nanocatalyst is 1 g:12 mL:0.07 g. (4) Concentrate the extract under reduced pressure at 50°C and recover ethanol until the volume of the concentrate is approximately 1 / 10 of the original volume; (5) The concentrate was further concentrated under reduced pressure at 50°C to a thick paste, and the concentrate was pre-cooled to -30°C to form ice particles. The concentrate was instantaneously sublimated and dried with hot air at 125°C under a low pressure environment of 0.02 MPa, and the discharge temperature was 45°C to finally obtain the chlorogenic acid extract; The preparation method of the Fe3O4@CQD nanocatalyst includes: Citric acid and urea were dissolved in deionized water at a molar ratio of 1:5.0, with a solid-liquid ratio of 0.3 g / mL. The mixture was hydrothermally reacted at 220°C for 6 h. After cooling, the mixture was dialyzed and purified with a molecular weight cut-off of 1000 Da to obtain a 10 mg / mL CQD solution. FeCl3·6H2O and FeCl2·4H2O were dissolved in nitrogen-deoxygenated deionized water at a molar ratio of 1:0.7 to a total iron ion concentration of 0.3 mol / L. Under nitrogen protection and mechanical stirring at 500 rpm, ammonia water was added dropwise to a pH of 11.0. The mixture was co-precipitated at 70°C for 60 min. The precipitate was collected by magnetic separation and washed with deoxygenated water until neutral to obtain Fe3O4 magnetic cores. The Fe3O4 magnetic cores were resuspended in the CQD solution with a weight ratio of Fe3O4:CQD of 1:0.5. Ultrasonic dispersion was performed at 40 kHz for 40 min. The solution was hydrothermally reacted at 180°C for 12 h. The product was separated by a magnetic field and dried in a vacuum at 60°C to constant weight.

[0023] Comparative Example 1 This comparative example provides a method for extracting chlorogenic acid from honeysuckle. In step (2), ultrasonic treatment is eliminated and replaced with constant temperature stirring at 50° C. for 120 min. The rest of the steps are the same as those in Example 1.

[0024] Comparative Example 2 This comparative example provides a method for extracting chlorogenic acid from honeysuckle. In step (3), the Fe3O4@CQD nanocatalyst is replaced by ordinary Fe3O4 nanoparticles without CQD loading, and the rest is the same as in Example 1.

[0025] Comparative Example 3 This comparative example provides a method for extracting chlorogenic acid from honeysuckle. During the preparation of Fe3O4@CQD nanocatalyst, the Fe3O4 magnetic core is replaced by alumina particles, and the rest is the same as in Example 1.

[0026] Comparative Example 4 This comparative example provides a method for extracting chlorogenic acid from honeysuckle, omitting step (3) of catalytic conversion of Chinese medicinal residues and product combination operations, and the rest is the same as in Example 1.

[0027] Comparative Example 5 This comparative example provides a method for extracting chlorogenic acid from honeysuckle. In step (5), the pre-cooling step is eliminated and 120°C hot air spray drying is directly adopted, with an inlet air temperature of 120°C and an outlet air temperature of 70°C. The rest is the same as in Example 1.

[0028] Comparative Example 6 This comparative example provides a method for extracting chlorogenic acid from honeysuckle, which adopts the ethanol reflux extraction method: step (1) honeysuckle pollen is mixed with 60% ethanol at a ratio of 1:25 (g / mL), and refluxed at 80°C for 2h, and the enzymatic hydrolysis, ultrasonication, and drug residue conversion steps are deleted. After concentration, the mixture was dried under forced air at 60°C.

[0029] Test Example 1: The chlorogenic acid extracts prepared by the methods of Examples 1-4 and Comparative Examples 1-6 were tested: Chlorogenic acid yield: HPLC method, chromatographic column: C18 reverse phase column (4.6 mm × 250 mm, 5 μm); mobile phase: acetonitrile-0.1% phosphoric acid aqueous solution (12:88, v / v); flow rate: 1.0 mL / min, detection wavelength: 327 nm, column temperature: 30°C; Calculation formula: Yield (%) = mass of chlorogenic acid in the extract / mass of raw material honeysuckle × 100%; Extract purity: Calculate the proportion of chlorogenic acid by normalizing the peak area of ​​HPLC chromatograms of the same batch; Solubility of the extract: 100 mg of the extract was dissolved in 10 mL of 60% ethanol aqueous solution, and the complete dissolution time was recorded; Water content of the extract: Dry in an oven at 105°C to constant weight and calculate the water content (%); Catalyst recovery rate: After magnetic separation, the catalyst was dried and weighed, and the recovery rate (%) was calculated; The test results are shown in Table 1 below (data are the mean ± standard deviation of 3 parallel experiments): Table 1

[0030] Combined with the above data, it can be seen that Examples 1-3 achieved a simultaneous improvement in the yield (6.05% to 6.95%) and purity (33.5% to 36.2%) of chlorogenic acid through an integrated process of enzymatic hydrolysis-ultrasonic synergistic extraction and catalytic conversion of medicinal residues, combined with instantaneous sublimation drying. Compared with the traditional ethanol method in Comparative Example 6, the yield was increased by 61% to 85%, and the purity was increased by 54% to 67%. In addition, the catalyst recovery rate was greater than 93%, the solvent usage was reduced, and the overall performance was optimal.

[0031] In Comparative Example 1, the ultrasonic cavitation effect is lacking, the cell wall is not fully broken, the dissolution efficiency is low, and the yield decreases by 36%; in Comparative Example 2, CQD is not loaded, the catalyst acid sites are insufficient, the conversion rate of chlorogenic acid precursor in the medicinal residue is low, and the yield decreases by 21%; in Comparative Example 3, the non-magnetic core leads to poor catalyst dispersion and recovery rate, low utilization rate of active components, and a decrease in catalyst recovery rate of 9%; in Comparative Example 4, the medicinal residue conversion step is deleted, and the chlorogenic acid precursor compound in the medicinal residue is not utilized, resulting in a loss of about 27% of the potential yield; in Comparative Example 5, spray drying replaces instantaneous sublimation drying, and the high temperature of 120°C causes degradation of heat-sensitive chlorogenic acid, an increase in by-products, and a decrease in purity by 31%; in Comparative Example 6, a traditional ethanol reflux method is used, without cell wall destruction means (enzyme / ultrasound), and high temperature and long-term extraction aggravate degradation, resulting in a 45% decrease in yield.

[0032] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for extracting chlorogenic acid from honeysuckle, characterized in that the steps include: (1) The honeysuckle powder obtained by drying and crushing the honeysuckle is mixed with citric acid-disodium hydrogen phosphate buffer, and a complex enzyme is added for enzymatic hydrolysis; (2) Adding ethanol aqueous solution to the enzymatic hydrolyzate, ultrasonically mixing, and then extracting; (3) After the extraction is completed, the mixture is cooled to room temperature and filtered to obtain a supernatant containing chlorogenic acid and a drug residue. The drug residue is mixed with a potassium dihydrogen phosphate solution, and a Fe3O4@CQD nanocatalyst is added. After a hydrothermal reaction, the catalyst is recovered and the liquid product containing the chlorogenic acid precursor compound is added to the supernatant to obtain an extract. (4) Concentrate the extract under reduced pressure and recover ethanol until the volume of the concentrate is approximately 1 / 5-1 / 10 of the original volume; (5) The concentrate is further concentrated under reduced pressure to a thick paste, and spray-dried to obtain the chlorogenic acid extract.

2. The method for extracting chlorogenic acid from honeysuckle according to claim 1, characterized in that: The pH value of the citric acid-disodium hydrogen phosphate buffer solution is 4.5-5.5, and the solid-liquid ratio of honeysuckle pollen to the citric acid-disodium hydrogen phosphate buffer solution is 1 g:15-25 mL.

3. The method for extracting chlorogenic acid from honeysuckle according to claim 1, characterized in that: The complex enzyme comprises cellulase and pectinase in a weight ratio of 1:1-2, and the addition amount of the complex enzyme is 1.0%-2.0% of the dry weight of honeysuckle pollen; the enzymolysis is performed by constant temperature oscillation at 45-55° C. for 60-90 minutes.

4. The method for extracting chlorogenic acid from honeysuckle according to claim 1, characterized in that: The volume fraction of ethanol in the ethanol aqueous solution is 30%-50%. After the ethanol aqueous solution is added in step (2), the solid-liquid ratio is adjusted to 1 g: 20-30 mL.

5. The method for extracting chlorogenic acid from honeysuckle according to claim 1, characterized in that: In step (2), the ultrasonic temperature is 40-50° C., the ultrasonic power is 200-400 W, the ultrasonic frequency is 20-40 kHz, and the ultrasonic time is 20-40 min.

6. The method for extracting chlorogenic acid from honeysuckle according to claim 1, characterized in that: The potassium dihydrogen phosphate solution is a 0.4-0.6 mol / L potassium dihydrogen phosphate aqueous solution, and the weight ratio of the medicinal residue, the potassium dihydrogen phosphate solution and the Fe3O4@CQD nanocatalyst is 1g:10-12mL:0.05-0.07g.

7. The method for extracting chlorogenic acid from honeysuckle according to claim 1, characterized in that: The preparation method of the Fe3O4@CQD nanocatalyst includes: dissolving citric acid and urea in water, carrying out a hydrothermal reaction at a temperature of 180-220°C for 4-6 hours, cooling and dialysis purification to obtain a CQD solution; resuspending Fe3O4 magnetic cores in the CQD solution, ultrasonically dispersing them, carrying out a hydrothermal reaction at a temperature of 160-180°C for 8-12 hours, separating and drying to obtain the catalyst.

8. The method for extracting chlorogenic acid from honeysuckle according to claim 7, characterized in that: The preparation method of the Fe3O4 magnetic core includes: dissolving FeCl3·6H2O and FeCl2·4H2O in nitrogen-deoxygenated deionized water to a total iron ion concentration of 0.1-0.3 mol / L; adding ammonia water dropwise to a pH of 9.0-11.0 under nitrogen protection and mechanical stirring at 300-500 rpm; performing a coprecipitation reaction at a temperature of 50-70°C for 30-60 minutes; collecting the precipitate by magnetic separation; and washing with deoxygenated water until neutral to obtain the Fe3O4 magnetic core.

9. The method for extracting chlorogenic acid from honeysuckle according to claim 7, characterized in that: The weight ratio of the Fe3O4 magnetic core to the CQD in the CQD solution is 1:0.2-0.

5.

10. The method for extracting chlorogenic acid from honeysuckle according to claim 1, characterized in that: The temperature of the hydrothermal reaction in step (3) is 170-190°C, and the time is 2-3 hours. The spray drying in step (5) adopts a low-pressure freeze-spray drying combined technology, and the concentrated liquid is pre-cooled to -20°C~-30°C to form ice particles, and is instantaneously sublimated and dried with hot air at 115-125°C in a low-pressure environment of 0.01-0.02MPa, and the discharge temperature is ≤45°C.

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