Method for extracting myricetin from Hovenia dulcis fruit

Abstract

The invention relates to the technical field of natural product extraction, and in particular to a method for extracting myricetin from Hovenia dulcis fruit. The method comprises the following steps: crushing the Hovenia dulcis fruit, sieving to obtain Hovenia dulcis fruit powder, firstly adding acid phosphatase to the Hovenia dulcis fruit powder for enzymolysis, then adding lipase for enzymolysis, then adding pectinase and cellulase for enzymolysis, filtering a mixture after the reaction of the pectinase and cellulase, collecting a filtrate, adding an alcohol solvent to the filtrate for extraction, concentrating the extract until there is no alcohol taste to obtain a crude myricetin extract, further purifying the crude myricetin extract, using a macroporous resin column chromatography method, collecting an eluate, separating a recovered myricetin solution, and using a freeze-drying method to obtain the myricetin powder.

Description

Technical Field

[0001] The present invention relates to the technical field of natural product extraction, in particular to a method for extracting myricetin from Hovenia dulcis fruit. Background Art

[0002] Myricetin is a natural flavonoid compound with diverse biological activities, including antioxidant, anti-inflammatory, and anti-tumor properties. Hovenia dulcis (Hovenia spinulosa) fruit is a common Chinese medicinal herb rich in myricetin. However, current methods for extracting myricetin from Hovenia dulcis fruit primarily rely on traditional aqueous and alcohol extraction methods. However, these methods suffer from low extraction efficiency and are time-consuming. Therefore, a method for extracting myricetin from Hovenia dulcis fruit that is both efficient and simple is urgently needed. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for extracting myricetin from Hovenia dulcis fruit, which has high extraction efficiency and is simple.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for extracting myricetin from Hovenia dulcis, comprising the following steps:

[0005] Step 1: Grind and sieve the Hovenia dulcis fruit to obtain Hovenia dulcis fruit powder;

[0006] Step 2: Acid phosphatase is first added to the Hovenia dulcis powder for enzymatic hydrolysis at a temperature of 35-40° C. for 1 hour. Lipase is then added for enzymatic hydrolysis at a temperature of 40-45° C. for 0.5-1 hour. Pectinase and cellulase are then added for enzymatic hydrolysis at a temperature of 40-50° C. for 1-2 hours.

[0007] Step 3: Filter the mixture after the reaction of pectinase and cellulase in step 2, and collect the filtrate;

[0008] Step 4: Add the filtrate to an alcohol solvent for extraction;

[0009] Step 5: Concentrate the extract until there is no alcohol taste, thereby obtaining a crude myricetin extract;

[0010] Step 6: further purifying the crude myricetin extract, adding the crude myricetin to a macroporous resin for elution, first eluting with pure water and then eluting with a propanol solution, collecting the myricetin eluate, separating the recovered myricetin solution, and freeze-drying to obtain myricetin powder;

[0011] The alcohol solvent added in step 4 is ethanol, and the volume fraction of the ethanol solvent is 50%-70%.

[0012] The beneficial effects of the present invention are as follows: by adding acid phosphatase to the Hovenia dulcis powder, since the cell wall of the Hovenia dulcis contains phosphate bonds, and the phosphate bonds connect the polysaccharide molecules, cellulose and pectin of the cell wall, acid phosphatase is used for enzymatic hydrolysis to separate the pectin and cellulose, and then lipase is added for enzymatic hydrolysis, and the lipase is used to act on the fat molecules of the Hovenia dulcis to emulsify them into small fat molecules. The small fat molecules can be filled between the pectin molecules to separate the pectin molecules, and the specific surface area of ​​the pectin molecules is increased. Under such a structure, the pectinase is used to act more effectively on the pectin molecules to break the plant cell wall, and the contact area between the enzyme and the substrate is increased, which is conducive to the enzymatic hydrolysis reaction, thereby improving the efficiency of the enzyme. In addition, the combination of the small fat molecules and pectin can also make the cell wall more flexible, which is conducive to the diffusion and action of pectinase and cellulase on the cell wall, so that the cell wall of the Hovenia dulcis cell wall releases more myricetin, thereby improving the extraction efficiency of the myricetin. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic structural diagram of the extraction device of the present invention;

[0014] Figure 2 Schematic diagram of the structure of the stirring device;

[0015] Figure 3 Circuit connection diagram of the controller.

[0016] Description of labels:

[0017] 1. Circular tank; 11. Through hole; 12. Feed pipe; 121. First solenoid valve; 2. Raw material box; 3. Stirring device; 31. Stirring shaft; 32. Stirring blade; 321. Material guide plate; 4. First tank; 5. Drive device; 51. First gear; 52. Second gear; 53. Drive motor; 6. First discharge pipe; 61. Second solenoid valve; 7. Second tank; 71. First pipe; 711. Third solenoid valve; 72. Second pipe ;721, fourth solenoid valve;73, third pipeline;731, fifth solenoid valve;74, second discharge pipe;741, sixth solenoid valve;8, filter;9, condensing device;91, third tank body;911, ethanol feed pipe;9111, seventh solenoid valve;912, third discharge pipe;9121, eighth solenoid valve;92, air outlet pipe;93, round pipe;931, water inlet;941, water outlet;94, condenser;95, collecting tank;10, fourth tank body;1001, propanol feed pipe;10011, ninth solenoid valve;1002, pure water feed pipe;10021, water pump;101, macroporous adsorption resin;102, fourth discharge pipe;103, fifth tank body;104, controller. DETAILED DESCRIPTION

[0018] To illustrate the technical content, achieved objectives and effects of the present invention in detail, the following description is given in conjunction with the embodiments and accompanying drawings.

[0019] A method for extracting myricetin from Hovenia dulcis fruit comprises the following steps:

[0020] Step 1: Select dried Hovenia dulcis fruit, grind it in a Chinese herbal medicine grinder, and then sieve it through 60 mesh to obtain Hovenia dulcis fruit powder;

[0021] Step 2: Acid phosphatase is first added to the Hovenia dulcis powder for enzymatic hydrolysis at a temperature of 35-40°C for 1 hour. After the enzymatic hydrolysis, lipase is then added for enzymatic hydrolysis at a temperature of 40-45°C for 0.5-1 hour. After the enzymatic hydrolysis, pectinase and cellulase are added for enzymatic hydrolysis at a temperature of 40-50°C for 1-2 hours.

[0022] In the above embodiment, acid phosphatase can be purchased commercially from Shanghai Yuanye Biological Co., Ltd., and lipase, pectinase and cellulase can be purchased commercially from Cangzhou Xiasheng Enzyme Biotechnology Co., Ltd.

[0023] Step 3: Filter the mixture after the reaction of pectinase and cellulase in step 2 to remove impurities and collect the filtrate. The mixture can be filtered through a filter, and the filter can be a Unite filter.

[0024] Step 4: Add ethanol to the filtered solution for extraction. The extraction time is 1 hour and the extraction temperature is 50-60°C.

[0025] Step 5: Concentrate the extract, recover ethanol, and concentrate until there is no alcohol taste to obtain a crude myricetin extract;

[0026] Step 6: The crude myricetin extract is further purified by macroporous resin column chromatography, the crude myricetin is eluted through a macroporous resin column layer, then eluted with pure water, and then eluted with a propanol solution, the myricetin solution is collected, and the myricetin solution is recovered. The recovery process temperature is controlled at 60-70°C, and the recovery time is 1-2 hours. The recovered myricetin solution is separated and freeze-dried to obtain myricetin powder.

[0027] Preferably, the freeze-drying temperature is -50°C to -30°C.

[0028] Preferably, the weight ratio of Hovenia dulcis powder, acid phosphatase, lipase, pectinase and cellulase is 5-10:1-2:1:2-4:2-4.

[0029] Preferably, in step 6, the myricetin crude product passes through the macroporous resin layer at a flow rate of 40-50 mg / g through the pretreated macroporous adsorption resin column layer.

[0030] Preferably, the macroporous resin is a macroporous adsorption resin of type D101, type AB-8, type LX-38, type D3520, type NKA-9, type D4020 or type S-8.

[0031] Please refer to Figures 1 to 3 A method for extracting myricetin from Hovenia dulcis fruit, based on an extraction device. A method for extracting myricetin from Hovenia dulcis fruit, based on an extraction device, comprising: a circular tank body 1, the outer wall of the circular tank body 1 being provided with a plurality of through holes 11, a feed pipe 12 being provided on the upper portion of the circular tank body 1, and a first solenoid valve 121 being provided on the feed pipe 12;

[0032] A raw material box 2 is connected to a feed pipe 12;

[0033] A stirring device 3 is located in the first circular tank body 1. The stirring device 3 includes a stirring shaft 31 and stirring blades 32. The stirring shaft 31 is a hollow cavity. A first filter 8 is provided on the outer wall of the stirring shaft 31. The first filter 8 is located between the stirring blades 32. A plurality of stirring blades 32 are connected to the outer wall of the stirring shaft 31. The plurality of stirring blades 32 are distributed in a circular array.

[0034] The first tank body 4 is in the shape of a body of revolution, which includes an upper cylindrical body and a lower conical body, and the circular tank body 1 is coaxially located in the upper cylindrical body;

[0035] The driving device 5 is used to drive the stirring shaft 31 to rotate. The driving device 5 includes a driving motor 53, a first gear 51 and a second gear 52. The second gear 52 is coaxially connected to the stirring shaft 31 for transmission. The first gear 51 is meshed with the second gear 52. The driving motor 53 is connected to the first gear 51 for transmission.

[0036] A first discharge pipe 6, which is connected to the lower part of the lower conical cavity and is provided with a second solenoid valve 61;

[0037] The second tank body 7, the upper portion of the second tank body 7 is connected to the first discharge pipe 6, the second tank body 7 is provided with a first pipe 71, a second pipe 72 and a third pipe 73, the first pipe 71 is used for adding acid phosphatase, the second pipe 72 is used for adding lipase, and the third pipe 73 is used for adding pectinase and cellulase. The first pipe 71 is provided with a third solenoid valve 711, the second pipe 72 is provided with a fourth solenoid valve 721, and the third pipe 73 is provided with a fifth solenoid valve 731. The lower portion of the second tank body 7 is provided with a second discharge pipe 74, and the second discharge pipe 74 is provided with a sixth solenoid valve 741;

[0038] The filter screen 8 is connected to the second discharge pipe 74 and is located below the sixth solenoid valve 741;

[0039] The condensing device 9 includes a third tank body 91, an air outlet pipe 92, a circular tube 93, a condensing pipe 94 and a collecting tank 95. The upper portion of the third tank body 91 is connected to the second discharge pipe 74. The third tank body 91 is provided with an ethanol feed pipe 911, and the ethanol feed pipe 911 is provided with a seventh solenoid valve 9111. The lower portion of the third tank body 91 is provided with a third discharge pipe 912, and the third discharge pipe 912 is provided with an eighth solenoid valve 9121. The third tank body 91 is connected to the collecting tank 95 through the air outlet pipe 92. The circular tube 93 is connected to the collecting tank 95. The circular tube 93 is provided with a water inlet 931 and a water outlet 941. The condensing pipe 94 is located in the circular tube 93. One end of the condensing pipe 94 is connected to the water outlet 941, and the other end of the condensing pipe 94 is connected to the water inlet 931.

[0040] The fourth tank body 10, the upper portion of the fourth tank body 10 is connected to the third discharge pipe 912, the fourth tank body 10 is provided with a macroporous adsorption resin 101, the lower portion of the fourth tank body 10 is provided with a fourth discharge pipe 102, the fourth tank body 10 is provided with a propanol feed pipe 1001 and a pure water feed pipe 1002, the propanol feed pipe 1001 is provided with a ninth solenoid valve 10011, and the pure water feed pipe 1002 is provided with a water pump 10021;

[0041] The fifth tank body 103, the upper portion of the fifth tank body 103 is connected to the fourth discharge pipe 102;

[0042] Controller 104, which is electrically connected to the first solenoid valve 121, the second solenoid valve 61, the third solenoid valve 711, the fourth solenoid valve 721, the fifth solenoid valve 731, the sixth solenoid valve 741, the seventh solenoid valve 9111, the eighth solenoid valve 9121, the ninth solenoid valve 10011, the water pump 10021, and the drive device 5;

[0043] In the above structure, a circular tank body 1, a raw material box 2, a stirring device 3, a first tank body 4, a driving device 5, a first discharge pipe 6, a second tank body 7, a filter screen 8, a condensing device 9, a fourth tank body 10, a fifth tank body 103 and a controller 104 are provided. The controller 104 is a PLC controller. After the Hovenia dulcis fruit is placed in the raw material box 2, the controller 104 controls the first solenoid valve 121 on the feed pipe 12 to open and close. Then, the controller 104 controls the driving device 5 to open and close, so that the stirring device 3 stirs in the circular tank body 1. The Hovenia dulcis fruit powder enters the first tank body 4 through the circular through hole 11. Then, the second solenoid valve 61 of the first discharge pipe 6 is opened, so that the Hovenia dulcis fruit powder in the first tank body 4 enters the second tank body 7. Compared with the traditional Chinese medicine pulverizing device in the prior art, the Hovenia dulcis fruit is pulverized by the stirring device 3 and falls into the first tank body 4 through the through hole 11, so that the Hovenia dulcis fruit powder has the same size.

[0044] Furthermore, the stirring blade 32 is provided with a guide plate 321, and the stirring blade 32 forms an angle of 130°-160° with the cross section of the stirring shaft 31, and the guide plate 321 forms an angle of 130°-160° with the cross section of the stirring shaft 31, and the guide plate 321 forms an angle of 120°-160° with the stirring blade 32.

[0045] In the above embodiment, the cross-section of the stirring blade 32 and the stirring shaft 31 forms an angle of 130°-160°, so that when the Hovenia dulcis is stirred, the Hovenia dulcis powder will not accumulate at the bottom of the circular tank body 11, but will be thrown upward. The guide plate 321 and the stirring blade 32 form an angle of 120°-160°, so that when the Hovenia dulcis is thrown up, the guide plate 321 guides the Hovenia dulcis to the through hole 11 of the circular tank body 1 through centrifugal action, thereby falling into the first tank body 4.

[0046] The specific operating steps of the extraction device are as follows:

[0047] Step 1: Dried Hovenia dulcis fruit is put into the raw material box 2. The controller 104 controls the first solenoid valve 121 to open, and the dried preparation is automatically put into the circular tank body 1. The controller 104 controls the driving device 5 to start, and the process lasts for 30 minutes. The Hovenia dulcis fruit powder falls into the first tank body 4 from the through hole 11. The controller 104 controls the driving device 5 to close. The controller 104 controls the second solenoid valve 61 to open, and the process lasts for 10 minutes. The powder in the first tank body 4 enters the second tank body 7. The controller 104 controls the second solenoid valve 61 to close. Since the powder can stick to the conical part of the first tank body 4, a vibrator is provided on the outer wall of the cone to shake the powder stuck in the cone into the first discharge pipe 6.

[0048] Step 2: The controller 104 controls the third solenoid valve 711 to open, and acid phosphatase is added to the first pipe 71 for 5 minutes. The controller 104 closes the third solenoid valve 711 for 1 hour. The controller 104 controls the fourth solenoid valve 721 to open, and lipase is added to the second pipe 72 for 5 minutes. The controller 104 closes the fourth solenoid valve 721 for 0.5 hours. The controller 104 controls the fifth solenoid valve 731 to open, and pectinase and cellulase are added to the third pipe 73 for 5 minutes. The controller 104 controls the fifth solenoid valve 731 to close for 1 hour.

[0049] Step 3: The controller 104 controls the sixth solenoid valve 741 to open, and the mixture passes through the filter screen 8 of the second discharge pipe 74 and enters the third tank 91;

[0050] Step 4: The controller 104 controls the seventh solenoid valve 9111 to open for 5 minutes, and then controls the seventh solenoid valve 9111 to close for 1 hour.

[0051] Step 5: The extract in the third tank 91 is concentrated by using the condensing device 9 to recover ethanol. The extraction temperature is 50-60°C for 1 hour. The extraction temperature can be maintained by providing an interlayer jacket in the third tank 91 and injecting hot water into the jacket. The interlayer jacket is a conventional technology and will not be described in detail here.

[0052] Step 6: The controller 104 controls the eighth solenoid valve 9121 to open for 30 minutes, so that the liquid in the third tank body passes through the macroporous adsorption resin 101, 45 mg / g passes through the pretreated macroporous adsorption resin bed, the controller controls the eighth solenoid to close, the controller controls the water pump to open, and elutes with pure water. The amount of pure water is 30% of the volume of the liquid in the third tank body, which lasts for 10 minutes. The controller controls the water pump to close, and the controller controls the ninth solenoid to open for 30 minutes. The propanol solution enters the fourth tank body, and the amount of propanol solution is 50%-60% of the volume of the liquid in the third tank body, so that the recovered myricetin liquid enters the fifth tank body 103, and the myricetin liquid in the fifth tank body 103 is freeze-dried. The recovery temperature is 60-70°C and the recovery time is 1 hour. The temperature can be maintained by providing an interlayer sleeve on the outer wall of the fourth tank body 10 and supplying and discharging hot water into the interlayer sleeve.

[0053] Example 1:

[0054] Step 1: Select dried Hovenia dulcis fruit, grind it in a Chinese herbal medicine grinder, and then sieve it through 60 mesh to obtain Hovenia dulcis fruit powder;

[0055] Step 2: Acid phosphatase is first added to the Hovenia dulcis powder for enzymatic hydrolysis at a temperature of 35°C for 1 hour. After the enzymatic hydrolysis, lipase is then added for enzymatic hydrolysis at a temperature of 40°C for 0.5 hour. After the enzymatic hydrolysis, pectinase and cellulase are added for enzymatic hydrolysis at a temperature of 40°C for 1 hour.

[0056] Step 3: Filter the mixture after the reaction of pectinase and cellulase in step 2 to remove impurities and collect the filtrate. The mixture can be filtered through a filter, and the filter can be a Unite filter.

[0057] Step 4: Add ethanol to the filtered solution for extraction. The extraction time is 1 hour and the extraction temperature is 50°C.

[0058] Step 5: Concentrate the extract, recover ethanol, and concentrate until there is no alcohol taste to obtain a crude myricetin extract;

[0059] Step 6: The crude myricetin extract is further purified by macroporous resin column chromatography. The crude myricetin is eluted through the macroporous resin column layer at a flow rate of 45 mg / g, and then eluted with pure water. The amount of pure water is 30% of the volume of the liquid in the third tank. Then, it is eluted with a propanol solution. The amount of propanol solution is 60% of the volume of the liquid in the third tank. The myricetin solution is collected and recovered. The recovery process control temperature is 60°C and the recovery time is 1 hour. The recovered myricetin solution is separated and freeze-dried to obtain myricetin powder.

[0060] Example 2:

[0061] Step 1: Select dried Hovenia dulcis fruit, grind it in a Chinese herbal medicine grinder, and then sieve it through 60 mesh to obtain Hovenia dulcis fruit powder;

[0062] Step 2: Acid phosphatase is first added to the Hovenia dulcis powder for enzymatic hydrolysis at a temperature of 37°C for 1 hour. After the enzymatic hydrolysis, lipase is then added for enzymatic hydrolysis at a temperature of 42°C for 1 hour. After the enzymatic hydrolysis, pectinase and cellulase are added for enzymatic hydrolysis at a temperature of 45°C for 2 hours.

[0063] Step 3: Filter the mixture after the reaction of pectinase and cellulase in step 2 to remove impurities and collect the filtrate. The mixture can be filtered through a filter, and the filter can be a Unite filter.

[0064] Step 4: Add ethanol to the filtered solution for extraction. The extraction time is 1 hour and the extraction temperature is 55°C.

[0065] Step 5: Concentrate the extract, recover ethanol, and concentrate until there is no alcohol taste to obtain a crude myricetin extract;

[0066] Step 6: The crude myricetin extract was further purified by macroporous resin column chromatography. The crude myricetin was eluted through the macroporous resin column layer at a flow rate of 50 mg / g, and then eluted with pure water. The amount of pure water was 30% of the volume of the liquid in the third tank. Then, propanol solution was used for elution. The amount of propanol solution was 60% of the volume of the liquid in the third tank. The myricetin solution was collected and recovered. The recovery process temperature was controlled at 65°C and the recovery time was 1.5 hours. The recovered myricetin solution was separated and freeze-dried to obtain myricetin powder.

[0067] Example 3:

[0068] Step 1: Select dried Hovenia dulcis fruit, grind it in a Chinese herbal medicine grinder, and then sieve it through 60 mesh to obtain Hovenia dulcis fruit powder;

[0069] Step 2: Acid phosphatase is first added to the Hovenia dulcis powder for enzymatic hydrolysis at a temperature of 40°C for 1 hour. After the enzymatic hydrolysis, lipase is then added for enzymatic hydrolysis at a temperature of 45°C for 1 hour. After the enzymatic hydrolysis, pectinase and cellulase are added for enzymatic hydrolysis at a temperature of 45°C for 2 hours.

[0070] Step 3: Filter the mixture after the reaction of pectinase and cellulase in step 2 to remove impurities and collect the filtrate. The mixture can be filtered through a filter, and the filter can be a Unite filter.

[0071] Step 4: Add ethanol to the filtered solution for extraction. The extraction time is 1 hour and the extraction temperature is 60°C.

[0072] Step 5: Concentrate the extract, recover ethanol, and concentrate until there is no alcohol taste to obtain a crude myricetin extract;

[0073] Step 6: The crude myricetin extract was further purified by macroporous resin column chromatography. The crude myricetin was eluted through the macroporous resin column layer at a flow rate of 55 mg / g, and then eluted with pure water. The amount of pure water was 30% of the volume of the liquid in the third tank. Then, propanol solution was used for elution. The amount of propanol solution was 60% of the volume of the liquid in the third tank. The recovery process control temperature was 70°C, and the recovery time was 2 hours. The recovered myricetin solution was separated and freeze-dried to obtain myricetin powder.

[0074] Comparative Example 1:

[0075] The difference from the method for extracting myricetin from Hovenia dulcis fruit in Example 1 is that step 2 is omitted.

[0076] Comparative Example 2:

[0077] The difference from the method for extracting myricetin from Hovenia dulcis fruit in Example 1 is that acid phosphatase, lipase, pectinase and cellulase are added simultaneously in step 2.

[0078] Comparative Example 3:

[0079] The difference between the method for extracting myricetin from Hovenia dulcis fruit in Example 1 is that no phosphatase and lipase are added in step 2.

[0080] Comparative Example 4:

[0081] The difference between the method for extracting myricetin from Hovenia dulcis fruit in Example 1 is that lipase is not added in step 2.

[0082] Comparative Example 5:

[0083] The difference from the method for extracting myricetin from Hovenia dulcis fruit in Example 1 is that acid phosphatase is not added in step 2.

[0084] The myricetin powders of Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4 and Comparative Example 5 were weighed. The results showed that the myricetin content prepared in Example 1 was 6.2 g, the myricetin content prepared in Example 2 was 6 g, the myricetin content prepared in Example 3 was 6.1 g, the myricetin content prepared in Comparative Example 1 was 3.3 g, the myricetin content prepared in Comparative Example 2 was 4.5 g, the myricetin content prepared in Comparative Example 3 was 4.3 g, the myricetin content prepared in Comparative Example 4 was 4.6 g, and the myricetin content prepared in Comparative Example 5 was 4.4 g. It can be seen that the myricetin content extracted in Example 1 of the present invention is the highest.

[0085] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's description and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for extracting myricetin from Hovenia dulcis, characterized in that: It includes the following steps: Step 1: Grind and sieve the Hovenia dulcis fruit to obtain Hovenia dulcis fruit powder; Step 2: Acid phosphatase is first added to the Hovenia dulcis powder for enzymatic hydrolysis at a temperature of 35-40° C. for 1 hour. Lipase is then added for enzymatic hydrolysis at a temperature of 40-45° C. for 0.5-1 hour. Pectinase and cellulase are then added for enzymatic hydrolysis at a temperature of 40-50° C. for 1-2 hours. Step 3: filtering the mixture after the reaction of pectinase and cellulase in step 2, and collecting the filtrate; Step 4: Add the filtrate to an alcohol solvent for extraction; Step 5: Concentrate the extract until there is no alcohol taste, thereby obtaining a crude myricetin extract; Step 6: further purifying the crude myricetin extract by macroporous resin column chromatography, collecting the eluate, separating the recovered myricetin solution, and freeze-drying to obtain myricetin powder; The alcohol solvent added in step 4 is ethanol, and the volume fraction of the ethanol solvent is 50%-70%.

2. The method for extracting myricetin from Hovenia dulcis fruit according to claim 1, wherein The temperature of the freeze-drying method is -50°C to -30°C.

3. The method for extracting myricetin from Hovenia dulcis fruit according to claim 1, wherein The weight ratio of Hovenia dulcis fruit powder, acid phosphatase, lipase, pectinase and cellulase is 5-10:1-2:1:2-4:2-4.

4. The method for extracting myricetin from Hovenia dulcis fruit according to claim 1, wherein In step 6, the crude myricetin passed through the macroporous resin layer is passed through the pretreated macroporous adsorption resin column layer at a flow rate of 40-50 mg / g.

5. The method for extracting myricetin from Hovenia dulcis fruit according to claim 1, wherein The macroporous resin is a macroporous adsorption resin, which is a D101 type, AB-8 type, LX-38 type, D3520 type, NKA-9 type, D4020 type or S-8 type macroporous adsorption resin.

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