Method for synergistically extracting procyanidine and dihydroquercetin from pine barks

Abstract

The invention discloses a method for synergistically extracting procyanidine and dihydroquercetin from pine barks, and belongs to the technical field of plant extraction.The method comprises the following steps that 1, the pine barks are smashed to obtain pine bark powder; step 2, adding an alcohol solution into the pine bark powder, and performing ultrasonic extraction to obtain a clear body; step 3, concentrating the clear body, standing, and taking an upper layer solution to obtain a pine bark crude extracting solution; step 4, adjusting the pH value of the pine bark crude extracting solution, and eluting the pine bark crude extracting solution through a resin chromatographic column to obtain a procyanidine eluent and a dihydroquercetin eluent; step 5, concentrating and crystallizing the dihydroquercetin eluent to obtain a crystal clear liquid and a crystal substance; and drying the crystal substance to obtain the dihydroquercetin. And step 6, merging the crystallization clear liquid and the procyanidine eluent, concentrating, and drying to obtain the procyanidine. According to the method, procyanidine and dihydroquercetin in pine barks can be efficiently extracted, the resource utilization rate is high, the technological process is simple, green and environmentally friendly, and the requirements of large-scale production are met.

Description

Technical Field

[0001] The invention belongs to the technical field of plant active ingredient extraction, and in particular relates to a method for synergistically extracting proanthocyanidins and dihydroquercetin from pine bark. Background Art

[0002] Pine bark is a byproduct of pine wood processing, containing a variety of active chemical components, and has extremely high development and utilization value. Among them, proanthocyanidins and dihydroquercetin are two extremely important functional compounds in pine bark, showing wide application potential in the fields of medicine, health products and cosmetics.

[0003] Proanthocyanidins are a class of natural polyphenol compounds that exist in the form of polymers. Their biological activities mainly manifest in anti-oxidation, cardiovascular protection, anti-inflammatory and anti-aging, and immune regulation. Studies have shown that the antioxidant capacity of proanthocyanidins is significantly better than that of vitamin C and vitamin E, and can effectively scavenge free radicals and inhibit oxidative stress reactions. Proanthocyanidins can reduce the risk of atherosclerosis and cardiovascular diseases by inhibiting the oxidation of low-density lipoproteins and improving vascular function. Its unique polyphenol structure can regulate inflammatory responses and reduce the release of inflammatory factors. It also has excellent performance in delaying skin aging. As a natural immune enhancer, proanthocyanidins show good potential in improving the body's immune function.

[0004] Dihydroquercetin is a typical representative of flavonoids and has attracted much attention due to its unique biological activity. Its main effects include: anti-inflammatory and antibacterial, antioxidant and microcirculation improvement, cardiovascular protection and immunomodulation. Dihydroquercetin relieves inflammatory responses by inhibiting the release of inflammatory factors and exhibits inhibitory effects on a variety of pathogens. Its potent antioxidant capacity can protect cells from free radical damage, while significantly improving microcirculation and promoting blood flow. Dihydroquercetin can reduce blood viscosity, enhance vascular elasticity, and has a good preventive and mitigating effect on cardiovascular diseases such as hypertension and coronary heart disease. In addition, it can also enhance the body's immunity and fight against external pathogens.

[0005] CN109574976B and CN102924420B disclose a method for preparing dihydroquercetin from larch roots; CN103360359B discloses a method for preparing dihydroquercetin from larch wood; CN118852085A discloses a highly water-soluble pine bark extract and a preparation method thereof; CN112159383A discloses a method for extracting proanthocyanidins using pine bark. CN105175380B discloses a method for preparing proanthocyanidins from Yunnan pine bark. The above technologies are only optimized for a single target component of dihydroquercetin or proanthocyanidins, resulting in waste or loss of the remaining active ingredients, and a low comprehensive resource utilization rate. CN105175380B discloses a method for preparing proanthocyanidins from Yunnan pine bark. The invention uses an enzyme-high-voltage pulsed electric field assisted extraction method. Although the extraction rate and purity are high, the equipment is expensive and the operation is complicated, which is not suitable for industrial natural product extraction and food industry. At the same time, the traditional method has low extraction efficiency and uses more organic solvents, which is not conducive to environmental protection.

[0006] The high molecular weight polymerization of proanthocyanidins and the small molecular weight of dihydroquercetin pose challenges to separation technology. So far, no research has been found that can simultaneously extract proanthocyanidins and dihydroquercetin from pine bark. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a method for synergistically extracting proanthocyanidins and dihydroquercetin from pine bark. The present invention can efficiently extract proanthocyanidins and dihydroquercetin from pine bark, improve resource utilization, and has a simple process flow, is green and environmentally friendly, meets the needs of large-scale production, promotes the development of the field of natural product extraction, and provides new technical support and application opportunities for the functional food, medicine and cosmetics industries.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for synergistically extracting proanthocyanidins and dihydroquercetin from pine bark, comprising the following steps:

[0010] Step 1, crushing pine bark to obtain pine bark powder;

[0011] Step 2, adding alcohol solution to the pine bark powder for ultrasonic extraction, solid-liquid separation, and obtaining a clear body;

[0012] Step 3, concentrating the clear body, standing it, taking the upper solution, and obtaining a crude pine bark extract;

[0013] Step 4, adjusting the pH value of the crude pine bark extract and then eluting it through a resin chromatography column, first eluting with pure water to remove impurities, then eluting with 2-6BV of the first eluent to obtain anthocyanidin eluent, and then eluting with 2-6BV of the second eluent to obtain a dihydroquercetin eluent;

[0014] Step 5, concentrating the dihydroquercetin eluate, performing solid-liquid separation, crystallizing, and performing secondary solid-liquid separation to obtain a crystal clear liquid and a crystal; and drying the crystal to obtain dihydroquercetin;

[0015] Step 6: Combine the crystallization clear solution and the proanthocyanidin eluate, concentrate, and dry to obtain proanthocyanidin.

[0016] Preferably, the pine tree in step 1 is at least one of larch bark, masson pine bark, tabulaeformis bark and mongolica pine bark.

[0017] Preferably, the pulverization in step 1 is pulverizing until it passes through a 20-120 mesh sieve; more preferably, it passes through a 40-100 mesh sieve; and even more preferably, it passes through a 40-80 mesh sieve.

[0018] Preferably, the alcohol solution in step 2 is a lower alcohol with a volume fraction of 30-90%; more preferably, a lower alcohol with a volume fraction of 40-80%; and even more preferably, a lower alcohol with a volume fraction of 40-60%.

[0019] Preferably, the volume ratio of the pine bark powder to the alcohol solution in step 2 is 1:5-15; more preferably 1:8-12.

[0020] Preferably, the lower alcohol in step 2 is at least one of methanol, ethanol, propanol and butanol.

[0021] Preferably, the ultrasonic extraction in step 2 is: ultrasonic treatment at least once at 300-500W, and each extraction time is 1-3h; more preferably, ultrasonic treatment is 1-3 times.

[0022] Preferably, the concentration in step 3 is to concentrate to 1 / 4-1 / 2 of the volume of the original clear liquid.

[0023] Preferably, the standing in step 3 is standing at room temperature for more than 4 hours; more preferably 4-6 hours.

[0024] Preferably, the pH value in step 4 is 1-5; more preferably 1-3.

[0025] Preferably, the resin in step 4 is at least one of polyamide resin, D101 macroporous resin, AB-8 macroporous resin and DA201 macroporous resin; preferably polyamide resin; further preferably, the mesh size of the polyamide resin is 30-60 mesh, 60-100 mesh or 100-200 mesh.

[0026] Preferably, the amount of pure water used in step 4 is 2-5 BV.

[0027] Preferably, in step 4, the first eluent is ethanol with a volume fraction of 25-50%; more preferably, it is ethanol with a volume fraction of 25-35%; and more preferably, it is ethanol with a volume fraction of 28-32%.

[0028] Preferably, in step 4, the second eluent is ethanol with a volume fraction of 30-55%; more preferably, it is ethanol with a volume fraction of 45-55%; and more preferably, it is ethanol with a volume fraction of 48-52%.

[0029] Preferably, the concentration in step 5 is to concentrate until the content of dihydroquercetin in the concentrated solution is 10-20 mg / mL.

[0030] Preferably, the crystallization in step 5 is as follows: adjusting the pH value of the filtrate to 1-3 and placing at 0-10° C. for 12-48 hours.

[0031] The beneficial effects of the present invention are:

[0032] (1) The present invention can efficiently extract proanthocyanidins and dihydroquercetin from pine bark, avoiding the loss of active ingredients and achieving high resource utilization.

[0033] (2) The process of the present invention is simple, uses less solvent, is green and environmentally friendly, meets the needs of large-scale production, promotes the development of the field of natural product extraction, and provides new technical support and application opportunities for the functional food, pharmaceutical and cosmetic industries. DETAILED DESCRIPTION

[0034] The following examples are only used to help understand the method of the present invention and its core idea. It should be noted that for those of ordinary skill in the art, without departing from the principles of the present invention, the present invention may also be subjected to several improvements and modifications, which also fall within the scope of protection of the claims of the present invention. The following description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present invention. It will be apparent to professionals and technicians in this field that various modifications to these embodiments, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but may be applied to a wider range consistent with the principles and novel features disclosed herein. Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those of ordinary skill in the art to which the present invention belongs.

[0035] It is worth mentioning that:

[0036] The purpose of the solid-liquid separation involved in the present invention is to achieve separation of the solid phase and the liquid phase. Therefore, conventional technical means such as centrifugation, filtration or filter pressing can be used.

[0037] The concentration in the present invention is concentration under reduced pressure.

[0038] The room temperature in the present invention is 20-25° C., and unless otherwise specified, all operations are performed at room temperature.

[0039] Unless otherwise specified, the solvents in the present invention are all pure water.

[0040] The following are examples and comparative examples of the present invention to illustrate the present invention in more detail, but the present invention is not limited thereto. The present invention does not limit the sources of the raw materials used. Unless otherwise specified, the raw materials used in the present invention are all common commercial products in the art.

[0041] [Detection method]

[0042] 1. Proanthocyanidin content detection

[0043] Refer to the instructions of the plant proanthocyanidin (OPC) content detection kit. Under acidic conditions, resorcinol and phloroglucinol on the A ring of plant proanthocyanidin react with vanillin to produce colored compounds with a characteristic absorption peak at 500nm. The 500nm light absorption value can be measured to calculate the proanthocyanidin content in the plant.

[0044] The sample was dried to constant weight, crushed, and passed through a 30-50 mesh sieve. 0.1 g was weighed, 1 mL of pure methanol solution was added, and extraction was performed by ultrasonic extraction (power 300 W, temperature 25 ° C, time 30 min); 12000 rpm, 25 ° C for 10 min, the supernatant was taken, and the volume was fixed to 1 mL with the extract solution for testing.

[0045] Preparation of standard solution: dilute the 10 mg / mL standard solution with the extract to make 4, 2.5, 1.25, 0.625, 0.3125, and 0.15625 mg / mL standard solutions.

[0046] The specific operations are shown in Table 1.

[0047] Table 1 Operation table

[0048]

[0049]

[0050] According to the concentration (x, mg / mL) and absorbance ΔA of the standard tube 标准 (y, ΔA 标准 ) to establish a standard curve. According to the standard curve, ΔA测定 (y, ΔA 测定 ) into the formula to calculate the sample concentration (x, mg / mL).

[0051] OPC content (mg / g mass) = x × V 提取 ÷W

[0052] In the formula,

[0053] x: sample concentration, mg / mL

[0054] V 提取 : Volume of extract added, 1mL;

[0055] W: sample mass, g.

[0056] 2. Dihydroquercetin content detection

[0057] Accurately weigh 0.5 g sample, extract with 50% ethanol ultrasonically for 30 min, with a solid-liquid ratio of 1:20, to obtain the test solution, centrifuge through a 0.45 μm filter membrane, and load the sample for detection. If the concentration is too high, it should be diluted appropriately.

[0058] Weigh a certain amount of standard, dissolve it in methanol to make up the volume, and then dilute it to 10, 25, 50, 100, 200 and 500 μg / mL.

[0059] Table 2 Elution schedule

[0060] Time / min Flow rate mL / min % A methanol %B 0.5% acetic acid aqueous solution 0 1.0 20 80 10 1.0 80 20 15 1.0 100 0 20 1.0 20 80 25 1.0 20 80

[0061] Flow rate: 1.0 mL / min, detection wavelength: 290 nm, injection volume: 10 μL. WATERS2695, PDA detector, ODS C18 (5 μm, 250×4.6 mm) chromatographic column.

[0062] The content of dihydroquercetin in the sample is calculated according to the following formula:

[0063]

[0064] Where:

[0065] X is the content of dihydroquercetin in the sample, in grams per 100 grams (g / 100g);

[0066] c is the concentration of dihydroquercetin, in micrograms per milliliter (μg / mL);

[0067] V1 is the total volume of the sample to be tested, 10 mL, in milliliters (mL);

[0068] F is the dilution factor;

[0069] m is the mass of the sample in milligrams (mg).

[0070] The calculation method of purity in the present invention is:

[0071]

[0072] Wherein, m1 is the mass of solid matter, g; m2 is the mass of proanthocyanidins or dihydroquercetin in the dried solid matter, g.

[0073] The recovery rate is calculated as:

[0074]

[0075] Wherein, m2 is the mass of proanthocyanidins or dihydroquercetin in the solid matter, g; m3 is the mass of proanthocyanidins or dihydroquercetin in the pine bark powder, g.

[0076] [Example] A method for synergistically extracting proanthocyanidins and dihydroquercetin from pine bark

[0077] Example 1

[0078] A method for synergistically extracting proanthocyanidins and dihydroquercetin from pine bark, comprising the following steps:

[0079] Step 1, crushing pine bark through a 40-mesh sieve to obtain pine bark powder;

[0080] Step 2, adding 50 (v / v)% ethanol solution to the pine bark powder at a solid-liquid ratio of 1:10 (v / v), performing ultrasonic extraction twice at 400W for 2 hours each time, and combining the filtrates after centrifugation to obtain a clear extract;

[0081] Step 3, the clear solution is concentrated under reduced pressure to 1 / 3 of the original clear solution volume, and allowed to stand at room temperature for 5 hours, the lower layer of jelly is removed, and the upper layer of solution is taken to obtain a crude pine bark extract;

[0082] Step 4, adding 1M hydrochloric acid to the crude pine bark extract, adjusting the pH value to 2, and eluting through a polyamide resin chromatography column (sample volume 0.3BV, adsorption 0.5h, polyamide resin 100-200 mesh);

[0083] Specifically: first use 3BV pure water at a flow rate of 3BV / h to elute and remove impurities;

[0084] Then, 4 BV of 30% ethanol was used for elution at a flow rate of 2 BV / h to obtain anthocyanidin eluate;

[0085] Finally, 4 BV of 50% ethanol was used for elution at a flow rate of 2 BV / h to obtain the dihydroquercetin eluate;

[0086] Step 5, the dihydroquercetin eluate is concentrated under reduced pressure until the content of dihydroquercetin in the concentrate is 10-20 mg / mL; the temperature is controlled to 85±2° C., filtered through 400 mesh gauze, cooled to room temperature, the pH of the filtrate is adjusted to 2, and allowed to stand at 4° C. for 24 hours to precipitate crystals, filtered through 400 mesh gauze to obtain a crystal clear liquid and crystals; the crystals are dried and crushed to obtain dihydroquercetin;

[0087] Step 6: Combine the crystallization clear solution and the proanthocyanidin eluate, concentrate under reduced pressure, and dry to obtain proanthocyanidin.

[0088] Example 2

[0089] A method for synergistically extracting proanthocyanidins and dihydroquercetin from pine bark, comprising the following steps:

[0090] Step 1, crushing pine bark through a 40-mesh sieve to obtain pine bark powder;

[0091] Step 2, adding 40 (v / v)% ethanol solution to the pine bark powder at a solid-liquid ratio of 1:8 (v / v), performing ultrasonic extraction twice at 300W for 3 hours each time, and combining the filtrates after centrifugation to obtain a clear extract;

[0092] Step 3, the clear solution is concentrated under reduced pressure to 1 / 2 of the original clear solution volume, and allowed to stand at room temperature for 6 hours, the lower layer of jelly is removed, and the upper layer of solution is taken to obtain a crude pine bark extract;

[0093] Step 4, adding 1M hydrochloric acid to the crude pine bark extract, adjusting the pH value to 1, and eluting through a polyamide resin chromatography column (sample volume 0.3BV, adsorption 0.5h, polyamide resin 100-200 mesh);

[0094] Specifically: first use 2BV pure water at a flow rate of 3BV / h to elute and remove impurities;

[0095] Then, 2 BV of 25% ethanol was used for elution at a flow rate of 2 BV / h to obtain anthocyanidin eluate;

[0096] Finally, 2 BV of 45% ethanol was used for elution at a flow rate of 2 BV / h to obtain the dihydroquercetin eluate;

[0097] Step 5, the dihydroquercetin eluate is concentrated under reduced pressure until the content of dihydroquercetin in the concentrate is 10-20 mg / mL; the temperature is controlled to 82±2° C., filtered through 400 mesh gauze, cooled to room temperature, the pH of the filtrate is adjusted to 1, and allowed to stand at 10° C. for 48 hours to precipitate crystals, filtered through 400 mesh gauze to obtain a crystal clear liquid and crystals; the crystals are dried and crushed to obtain dihydroquercetin;

[0098] Step 6: Combine the crystallization clear solution and the proanthocyanidin eluate, concentrate under reduced pressure, and dry to obtain proanthocyanidin.

[0099] Example 3

[0100] A method for synergistically extracting proanthocyanidins and dihydroquercetin from pine bark, comprising the following steps:

[0101] Step 1, crushing pine bark through a 40-mesh sieve to obtain pine bark powder;

[0102] Step 2, adding 60 (v / v)% ethanol solution to the pine bark powder at a solid-liquid ratio of 1:12 (v / v), performing ultrasonic extraction at 500W for 3 times, each time for 1 hour, centrifuging and combining the filtrates to obtain a clear extract;

[0103] Step 3, the clear solution is concentrated under reduced pressure to 1 / 4 of the original clear solution volume, and allowed to stand at room temperature for 4 hours, the lower layer of jelly is removed, and the upper layer of solution is taken to obtain a crude pine bark extract;

[0104] Step 4, adding 1M hydrochloric acid to the crude pine bark extract, adjusting the pH value to 3, and eluting through a polyamide resin chromatography column (sample loading volume 0.3BV, adsorption 0.5h, polyamide resin 100-200 mesh);

[0105] Specifically: first use 5BV pure water at a flow rate of 3BV / h to elute and remove impurities;

[0106] Then, 6 BV of 35% ethanol was used for elution at a flow rate of 2 BV / h to obtain anthocyanidin eluate;

[0107] Finally, 6 BV of 55% ethanol was used for elution at a flow rate of 2 BV / h to obtain the dihydroquercetin eluate;

[0108] Step 5, the dihydroquercetin eluate is concentrated under reduced pressure until the content of dihydroquercetin in the concentrate is 10-20 mg / mL; the temperature is controlled to 88±2° C., filtered through 400 mesh gauze, cooled to room temperature, the pH of the filtrate is adjusted to 3, and allowed to stand at 0° C. for 12 hours to precipitate crystals, filtered through 400 mesh gauze to obtain a crystal clear liquid and crystals; the crystals are dried and crushed to obtain dihydroquercetin;

[0109] Step 6: Combine the crystallization clear solution and the proanthocyanidin eluate, concentrate under reduced pressure, and dry to obtain proanthocyanidin.

[0110] Comparative Example 1

[0111] The difference between this comparative example and Example 1 is that the first eluent and the second eluent are different.

[0112] Specifically:

[0113] Step 4, adding 1M hydrochloric acid to the crude pine bark extract, adjusting the pH value to 2, and eluting through a polyamide resin chromatography column;

[0114] Specifically: first use 3BV pure water at a flow rate of 3BV / h to elute and remove impurities;

[0115] Then, 4 BV of 30% ethanol was used for elution at a flow rate of 2 BV / h to obtain anthocyanidin eluate;

[0116] Finally, 4 BV of 30% ethanol was used for elution at a flow rate of 2 BV / h to obtain the dihydroquercetin eluate;

[0117] The remaining steps are the same as in Example 1.

[0118] Comparative Example 2

[0119] The difference between this comparative example and Example 1 is that the first eluent and the second eluent are different.

[0120] Specifically:

[0121] Step 4, adding 1M hydrochloric acid to the crude pine bark extract, adjusting the pH value to 2, and eluting through a polyamide resin chromatography column;

[0122] Specifically: first use 3BV pure water at a flow rate of 3BV / h to elute and remove impurities;

[0123] Then, 4 BV of 10% ethanol was used for elution at a flow rate of 2 BV / h to obtain an eluate of proanthocyanidins;

[0124] Finally, 4 BV of 70% ethanol was used for elution at a flow rate of 2 BV / h to obtain the dihydroquercetin eluate;

[0125] The remaining steps are the same as in Example 1.

[0126] Comparative Example 3

[0127] The difference between this comparative example and Example 1 is that the first eluent and the second eluent are different.

[0128] Specifically:

[0129] Step 4, adding 1M hydrochloric acid to the crude pine bark extract, adjusting the pH value to 2, and eluting through a polyamide resin chromatography column;

[0130] Specifically: first use 3BV pure water at a flow rate of 3BV / h to elute and remove impurities;

[0131] Then, 4 BV of 70% ethanol was used for elution at a flow rate of 2 BV / h to obtain anthocyanidin eluate;

[0132] Finally, 4 BV of 10% ethanol was used for elution at a flow rate of 2 BV / h to obtain the dihydroquercetin eluate;

[0133] The remaining steps are the same as in Example 1.

[0134] Comparative Example 4

[0135] The difference between this comparative example and Example 1 is that the pH value of the crude pine bark extract is different.

[0136] Specifically: Step 4, add 1M sodium hydroxide to the crude pine bark extract to adjust the pH value to 9.

[0137] The remaining steps are the same as in Example 1.

[0138] Comparative Example 5

[0139] The difference between this comparative example and Example 1 is only that the crystallization temperature of dihydroquercetin is different.

[0140] Specifically:

[0141] Step 5, the dihydroquercetin eluate is concentrated under reduced pressure until the content of dihydroquercetin in the concentrate is 10-20 mg / mL; the temperature is controlled to 85±2° C., filtered through 400 mesh gauze, cooled to room temperature, the pH of the filtrate is adjusted to 2, and allowed to stand at 15° C. for 24 hours to precipitate crystals, filtered through 400 mesh gauze to obtain a crystal clear liquid and crystals; the crystals are dried and crushed to obtain dihydroquercetin;

[0142] The remaining steps are the same as in Example 1.

[0143] The recovery rates and purities of dihydroquercetin and proanthocyanidins extracted in the examples are shown in Table 3 below.

[0144] Table 3 Recovery and purity of dihydroquercetin and proanthocyanidins

[0145]

[0146] The above is a further description of the present invention in conjunction with specific embodiments, but these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solution of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, but these modifications and replacements all fall within the scope of protection of the present invention.

Claims

1. A method for synergistically extracting proanthocyanidins and dihydroquercetin from pine bark, characterized in that: The steps include: Step 1, crushing pine bark to obtain pine bark powder; Step 2, adding alcohol solution to the pine bark powder for ultrasonic extraction, solid-liquid separation, and obtaining a clear body; Step 3, concentrating the clear body, standing it, taking the upper solution, and obtaining a crude pine bark extract; Step 4, adjusting the pH value of the crude pine bark extract to 1-5 and then eluting through a resin chromatography column, first eluting with pure water to remove impurities, eluting with 2-6BV of the first eluent to obtain anthocyanidin eluent, and then eluting with 2-6BV of the second eluent to obtain a dihydroquercetin eluent; Step 5, concentrating the dihydroquercetin eluate, performing solid-liquid separation, crystallizing, and performing secondary solid-liquid separation to obtain a crystal clear liquid and a crystal; and drying the crystal to obtain dihydroquercetin; Step 6, combining the crystallization clear solution and the proanthocyanidin eluate, concentrating, and drying to obtain proanthocyanidin; The resin in step 4 is at least one of polyamide resin, D101 macroporous resin, AB-8 macroporous resin and DA201 macroporous resin; In step 4, the first eluent is ethanol with a volume fraction of 25-50%, and the second eluent is ethanol with a volume fraction of 45-55%; The crystallization in step 5 is as follows: adjusting the pH value of the filtrate to 1-3 and placing it at 0-10°C for 12-48h.

2. The method according to claim 1, characterized in that The pine tree in step 1 is at least one of larch bark, masson pine bark, tabulaeformis bark and mongolica pine bark.

3. The method according to claim 1, characterized in that The alcohol solution in step 2 is a lower alcohol with a volume fraction of 30-90%; the lower alcohol is at least one of methanol, ethanol, propanol and butanol.

4. The method according to claim 1, characterized in that: The ultrasonic extraction in step 2 is: ultrasonic treatment at least once at 300-500W, and each extraction time is 1-3h.

5. The method according to claim 1, characterized in that The concentration in step 3 is to concentrate to 1 / 4-1 / 2 of the original clear liquid volume; And / or, the standing is standing at room temperature for more than 4 hours.

6. The method according to claim 1, characterized in that The resin is a polyamide resin; the mesh number of the polyamide resin is 60-200 meshes.

7. The method according to claim 1, characterized in that The pH value in step 4 is 1-3.

8. The method according to claim 1, characterized in that: The amount of pure water used in step 4 is 2-5BV.

9. The method according to claim 1, characterized in that: In step 4, the first eluent is ethanol with a volume fraction of 25-35%; And / or, the second eluent is ethanol with a volume fraction of 45-55%.

10. The method according to claim 1, characterized in that The concentration in step 5 is to concentrate until the content of dihydroquercetin in the concentrated solution is 10-20 mg / mL.

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