Method for efficiently extracting high-purity baicalin and baical skullcap root flavone from baical skullcap root

Abstract

The invention provides a method for efficiently extracting high-purity baicalin and baical skullcap root flavone from baical skullcap root. The method comprises the following steps: extracting baical skullcap root, concentrating, and carrying out acid precipitation to obtain a filter cake; pulping a filter cake, dissolving with ethanol, adsorbing with macroporous adsorption resin, respectively resolving with low-concentration ethanol and high-concentration ethanol, and drying a high-concentration resolving solution to obtain scutellaria baicalensis flavone; and combining the low-concentration desorption solution with the feed effluent, carrying out gradient elution by using a reversed-phase chromatographic column, collecting target components, concentrating by using a reverse osmosis membrane, adjusting the pH value, crystallizing and filtering, and drying a filter cake to obtain the high-purity baicalin. According to the method, acid precipitation, resin impurity removal and reversed-phase chromatography purification are combined, so that the two products are efficiently and synchronously separated, the waste liquid is recycled, the product yield is increased, and the cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of plant extraction technology, specifically to a method for efficiently extracting high-purity baicalin and baicalein flavonoids from Scutellaria baicalensis root. Background Technology

[0002] Scutellaria baicalensis is a perennial herb belonging to the genus Scutellaria in the Lamiaceae family. Its dried root is a commonly used traditional Chinese medicine, listed in the Pharmacopoeia of the People's Republic of my country, and has the effects of clearing heat and drying dampness, purging fire and detoxifying, stopping bleeding and calming the fetus. Modern pharmacological studies have shown that the core medicinal components of Scutellaria baicalensis are flavonoids, among which baicalin and baicalein flavonoids are the most representative active substances. Baicalin has anti-inflammatory, antibacterial, antiviral, and cardiovascular protective pharmacological effects, and is widely used in the pharmaceutical and health product fields; baicalein exhibits excellent activity in anti-oxidation, anti-tumor, and skin care, and is an important raw material in the cosmetics and food additive industries. With the increasing market demand for natural active ingredients, the efficient and green recovery of high-purity baicalin and baicalein flavonoids from Scutellaria baicalensis root has become a research hotspot in the field of Scutellaria baicalensis processing.

[0003] Currently, the main methods for extracting and separating baicalin and baicalein flavonoids from Scutellaria baicalensis roots include water extraction, alcohol extraction, and alkali extraction. These methods generally suffer from low yields, insufficient purity, poor environmental friendliness, or low resource utilization, necessitating further purification. To improve the yield and purity of the active ingredients, macroporous adsorption resin methods have been widely used. Macroporous adsorption resin methods can effectively enrich flavonoid components through adsorption and solvent elution. However, when processing complex Scutellaria baicalensis extracts, relying solely on resin separation often fails to completely separate structurally similar baicalin from other flavonoid components, resulting in product purity still falling short of requirements. To obtain a single high-purity component, multiple resin column purifications are typically required, a cumbersome process with low product yields. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a method for efficiently extracting high-purity baicalin and baicalein flavonoids from Scutellaria baicalensis root, addressing the shortcomings of existing technologies. This method uses a coupled approach of acid precipitation for preliminary separation, macroporous resin for directional impurity removal, and reversed-phase chromatography for deep purification. This method simultaneously separates high-purity baicalin and baicalein flavonoids from the Scutellaria baicalensis extract. The waste liquid generated during the purification process is recycled back into the extract for recycling, thereby reducing production costs and increasing the yield of the target products.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A method for efficiently extracting high-purity baicalin and baicalein flavonoids from Scutellaria baicalensis root includes the following steps:

[0007] (1) After the root of Scutellaria baicalensis was crushed, it was extracted with water and filtered to obtain the extract;

[0008] (2) The extract is heated and concentrated to obtain concentrate one. The pH of concentrate one is adjusted, the precipitate is stirred and then filtered to obtain filtrate one and filter cake one.

[0009] (3) Mix filter cake one and purified water to make a slurry, adjust the pH of the system to obtain solution one to be treated, mix solution one to be treated with ethanol solution and heat until the solid dissolves to obtain solution two to be treated;

[0010] (4) The liquid to be treated is treated by adsorption of macroporous adsorption resin. After adsorption, it is eluted by low concentration ethanol solution and high concentration ethanol solution in sequence. The elution liquid one and elution liquid two are collected respectively. The elution liquid two is dried to obtain Scutellaria baicalensis flavonoids. The feed effluent and elution liquid one are combined to obtain the liquid to be treated three.

[0011] (5) The solution to be treated is pumped into a chromatographic column packed with reversed-phase chromatographic packing for separation. After the feed is completed, gradient elution is performed sequentially with the first ethanol solution, the second ethanol solution, and the third ethanol solution. Eluent 1, eluent 2, and eluent 3 are collected respectively. Eluent 3 is combined into eluent 2.

[0012] (6) The eluent is concentrated using a reverse osmosis membrane to obtain a retentate with a solid content of 3-4% and an ethanol concentration of 35-40% v / v;

[0013] (7) Heat the above retentate and adjust the pH, then stir to crystallize. After crystallization, filter while hot to obtain filter cake 2 and filtrate 2. Dry filter cake 2 to obtain high-purity baicalin.

[0014] Preferably, in step (1), the mass ratio of Scutellaria baicalensis root to water is 1:(8-10), the extraction temperature is 100℃, the extraction time is 30-60 min each time, and the number of extractions is 2-3 times.

[0015] Preferably, in step (2), the solid content of the first concentrate is 14-18%; and / or the pH of the first concentrate is adjusted to 1.5-1.8; and / or the temperature when adjusting the pH of the first concentrate is 60-75℃; and / or the stirring and sedimentation time is more than 30 minutes.

[0016] Preferably, in step (3), the preparation of the second liquid to be treated includes at least one of the following characteristics:

[0017] The mass ratio of filter cake to purified water is 1:(25-30);

[0018] The pH of the system was adjusted to 5.2-5.5;

[0019] The solid content of the second liquid to be treated is 1.3-1.8 wt%, and the ethanol concentration in the second liquid to be treated is 25-30% v / v.

[0020] Preferably, in step (4), the macroporous adsorption resin is one of D101 or AB-8; and / or during adsorption treatment, each 100ml of resin treats a batch of liquid to be treated with a dry weight of 65-72g; and / or the feed flow rate during adsorption treatment is 0.5-2BV / h of the resin volume.

[0021] Preferably, in step (4), the concentrations of the low-concentration ethanol solution and the high-concentration ethanol solution are 25-30% v / v and 65-80% v / v, respectively; and / or the amount of the low-concentration ethanol solution used is 2-3 BV of the resin volume, and the amount of the high-concentration ethanol solution used is 2.5-4 BV of the resin volume; and / or the inlet flow rate when using the low-concentration ethanol solution and the high-concentration ethanol solution for analysis is 0.5-1.5 BV / h of the resin volume.

[0022] Preferably, in step (5), the reversed-phase chromatography packing material is UniSil® reversed-phase silica gel chromatography packing material with a particle size of 30-50μm and a pore size of 120-150Å; and / or the feed rate is 2-3g of the dry weight of the liquid to be treated per 100ml of reversed-phase chromatography packing material per batch; and / or the feed flow rate is 0.5-1.0BV / h of the volume of the reversed-phase chromatography packing material.

[0023] Preferably, in step (5), the concentrations of the first ethanol solution, the second ethanol solution, and the third ethanol solution are 30-32% v / v, 55-58% v / v, and 78-83% v / v, respectively.

[0024] Preferably, in step (5), when eluting with the first ethanol solution, the amount of the first ethanol solution is 1.0-1.5 BV of the reversed-phase chromatography packing volume, and the feed flow rate is 0.5-1.0 BV / h of the reversed-phase chromatography packing volume; and / or when eluting with the second ethanol solution, the amount of the second ethanol solution is 1.7-2.0 BV of the reversed-phase chromatography packing volume, and the feed flow rate is 0.5-1.0 BV / h of the reversed-phase chromatography packing volume; and / or when eluting with the third ethanol solution, the amount of the third ethanol solution is 2.0-2.8 BV of the reversed-phase chromatography packing volume, and the feed flow rate is 1.0-2.0 BV / h of the reversed-phase chromatography packing volume.

[0025] Preferably, in step (5), the eluent is mixed with the feed effluent and then de-alcoholized, and then mixed with the extract for the next batch of processing.

[0026] Preferably, in step (6), the process of concentrating the eluent using a reverse osmosis membrane includes: concentrating the eluent II using a reverse osmosis membrane until the ethanol concentration in the permeate is 35-40% v / v, then using ethanol of 35-40% concentration as feed, and mixing the concentrated solution and the ethanol feed solution to obtain the retentate.

[0027] Preferably, in step (6), the temperature during reverse osmosis membrane concentration is 25-50℃ and the pressure is 0.6-3.0MPa.

[0028] Preferably, in step (7), the process of heating and adjusting the pH of the retentate includes at least one of the following features:

[0029] The retentate is heated to a temperature of 65-75℃;

[0030] Adjust the pH of the retentate to 2.0-2.3;

[0031] The stirring time for crystallization is 10-25 minutes.

[0032] Preferably, in step (7), after the filtrate 2 is mixed with the eluent 1 to remove alcohol, it is recovered into the extract for the next batch of processing.

[0033] By adopting the above technical solution, the present invention has at least the following beneficial effects:

[0034] 1. This invention provides a method for efficiently extracting high-purity baicalin and baicalein flavonoids from Scutellaria baicalensis root. The method involves a combined process of water extraction, acid precipitation for preliminary separation, macroporous resin for directional impurity removal, and reversed-phase chromatography for deep purification. By utilizing the polarity difference and physicochemical properties of baicalin and baicalein flavonoids, the two target products can be simultaneously separated and recovered.

[0035] 2. In this invention, when using macroporous adsorption resin for adsorption, impurities and some baicalin are first eluted with low-concentration ethanol, and then scutellaria baicalensis flavonoids are enriched with high-concentration ethanol to avoid the loss of flavonoid components. In addition, the solid content, ethanol solubility, pH and other conditions of the solution are effectively adjusted before adsorption by macroporous adsorption resin to effectively increase the polarity difference between each effective component, thereby improving the separation efficiency.

[0036] 3. When using medium- and low-pressure chromatography for separation, this invention achieves the directional separation of baicalin and residual impurities by selecting the type of chromatographic packing material and using a three-stage elution method, and by optimizing the elution conditions at each stage. During subsequent crystallization, this invention achieves rapid crystallization of baicalin and removal of impurities by controlling the crystallization temperature and solution pH in combination, thereby improving the purity of baicalin.

[0037] 4. In this invention, the initial elution impurity segment and baicalin crystal mother liquor separated by chromatography are recovered into the extract after being de-alcoholized for the next batch of processing. This not only reduces the amount of waste liquid generated, but also maximizes the recovery of effective components. Detailed Implementation

[0038] To better understand the above-mentioned objectives, features, and advantages of the present invention, the solutions of the present invention will be further described below. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other.

[0039] Many specific details are set forth in the following description in order to provide a full understanding of the invention, but the invention may also be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of the invention, and not all embodiments.

[0040] This invention provides a method for efficiently recovering high-purity baicalin and baicalein from Scutellaria baicalensis root, comprising the following steps:

[0041] (1) After the root of Scutellaria baicalensis was crushed, it was extracted with water and filtered to obtain the extract;

[0042] (2) Heat and concentrate the extract to obtain concentrate one. Adjust the pH of concentrate one, stir to precipitate, and then filter to obtain filtrate one and filter cake one. Filtrate one is reserved for other uses.

[0043] (3) Mix filter cake one and purified water to make a slurry, adjust the pH of the system to obtain solution one to be treated, mix solution one to be treated with ethanol solution and heat until the solid dissolves to obtain solution two to be treated;

[0044] (4) The liquid to be treated is treated by adsorption of macroporous adsorption resin. After adsorption, it is eluted by low concentration ethanol solution and high concentration ethanol solution in sequence. The elution liquid one and elution liquid two are collected respectively. The elution liquid two is dried to obtain Scutellaria baicalensis flavonoids. The feed effluent and elution liquid one are combined to obtain the liquid to be treated three.

[0045] (5) The solution to be treated is pumped into a chromatographic column packed with reversed-phase chromatographic packing for separation. After the feed is completed, gradient elution is performed sequentially with the first ethanol solution, the second ethanol solution, and the third ethanol solution. Eluent 1, eluent 2, and eluent 3 are collected respectively. Eluent 3 is combined into eluent 2.

[0046] (6) The eluent is concentrated using a reverse osmosis membrane to obtain a retentate with a solid content of 3-4% and an ethanol concentration of 35-40% v / v;

[0047] (7) Heat the above retentate and adjust the pH, then stir to crystallize. After crystallization, filter while hot to obtain filter cake 2 and filtrate 2. Dry filter cake 2 to obtain high-purity baicalin.

[0048] Regarding step (1):

[0049] In some embodiments, in step (1), the mass ratio of Scutellaria baicalensis root to water is 1:(8-10), the extraction temperature is 100℃, the extraction time is 30-60 min each time, and the number of extractions is 2-3 times.

[0050] This invention uses water as the extraction solvent, avoiding organic solvent residue. Furthermore, by effectively adjusting the material-to-liquid ratio, extraction temperature, and number of extractions, this invention ensures extraction efficiency while effectively controlling the volume of the extract, thus reducing energy consumption.

[0051] Regarding step (2):

[0052] In some embodiments, in step (2), the solid content of the first concentrate is 14-18%. Too high a concentration can easily lead to co-precipitation of impurities, while too low a concentration can lead to low precipitation efficiency; and / or the pH of the first concentrate is adjusted to 1.5-1.8; and / or the temperature when adjusting the pH of the first concentrate is 60-75°C, taking advantage of the physicochemical property that the solubility of baicalin drops sharply under specific temperature and acidic conditions, to achieve the initial separation of baicalin, baicalein flavonoids and some water-soluble impurities; and / or the stirring precipitation time is more than 30 minutes.

[0053] The unprecipitated scutellaria flavonoids remaining in the first filtrate were recovered by resin adsorption alone.

[0054] Regarding step (3):

[0055] In some embodiments, step (3) of preparing the second liquid to be treated includes at least one of the following characteristics:

[0056] The mass ratio of filter cake to purified water is 1:(25-30);

[0057] The pH of the system was adjusted to 5.2-5.5 to deprotonate the carboxyl group of baicalin, thereby increasing its water solubility.

[0058] The solid content of the liquid to be treated is 1.3-1.8 wt%, and the ethanol concentration is 25-30% v / v, which facilitates subsequent adsorption and separation by macroporous resin.

[0059] Regarding step (4):

[0060] In some embodiments, in step (4), the macroporous adsorption resin is of type D101 or AB-8; and / or during adsorption treatment, each 100 ml of resin processes a batch of the liquid to be treated with a dry weight of 65-72 g; and / or the feed flow rate during adsorption treatment is 0.5-2 BV / h of the resin volume. Baicalin, baicalein flavonoids, and other components in the liquid to be treated are separated by utilizing the adsorption effect of the macroporous adsorption resin and the elution capacity of ethanol at different concentrations.

[0061] In some embodiments, in step (4), the concentrations of the low-concentration ethanol solution and the high-concentration ethanol solution are 25-30% v / v and 65-80% v / v, respectively. The low-concentration ethanol solution elutes highly polar impurities and some baicalin, while the high-concentration ethanol solution elutes less polar and more strongly adsorbed scutellarin flavonoids. And / or the amount of the low-concentration ethanol solution used is 2-3 BV of the resin volume, and the amount of the high-concentration ethanol solution used is 2.5-4 BV of the resin volume. And / or the inlet flow rate when using the low-concentration ethanol solution and the high-concentration ethanol solution for desorption is 0.5-1.5 BV / h of the resin volume.

[0062] Regarding step (5):

[0063] In some embodiments, in step (5), the reversed-phase chromatography packing material is UniSil® reversed-phase silica gel chromatography packing material with a particle size of 30-50 μm and a pore size of 120-150 Å; and / or the feed rate is 2-3 g of the dry matter weight of the solution to be treated per 100 ml of reversed-phase chromatography packing material per batch; and / or the feed flow rate is 0.5-1.0 BV / h of the volume of the reversed-phase chromatography packing material.

[0064] In some embodiments, in step (5), the concentrations of the first ethanol solution, the second ethanol solution, and the third ethanol solution are 30-32% v / v, 55-58% v / v, and 78-83% v / v, respectively, to achieve efficient separation by utilizing the small differences in the partition coefficients of the components in the three solutions to be treated between the stationary phase and the mobile phase.

[0065] In some embodiments, in step (5), when eluting with a first ethanol solution, the amount of the first ethanol solution is 1.0-1.5 BV of the reversed-phase chromatography packing volume, and the feed flow rate is 0.5-1.0 BV / h of the reversed-phase chromatography packing volume, to elute residual highly polar impurities; and / or when eluting with a second ethanol solution, the amount of the second ethanol solution is 1.7-2.0 BV of the reversed-phase chromatography packing volume, and the feed flow rate is 0.5-1.0 BV / h of the reversed-phase chromatography packing volume, at this concentration, baicalin is selectively eluted; and / or when eluting with a third ethanol solution, the amount of the third ethanol solution is 2.0-2.8 BV of the reversed-phase chromatography packing volume, and the feed flow rate is 1.0-2.0 BV / h of the reversed-phase chromatography packing volume, at this concentration, impurities with lower polarity are eluted and combined into the second eluent to ensure the yield of scutellaria baicalensis flavonoids.

[0066] In some embodiments, in step (5), the eluent is mixed with the feed effluent and then de-alcoholized, and then mixed with the extract for the next batch of processing.

[0067] Regarding step (6):

[0068] In some embodiments, step (6), the process of concentrating the eluent using a reverse osmosis membrane, includes: concentrating the eluent using a reverse osmosis membrane until the ethanol concentration in the permeate is 35-40% v / v; then using a feed solution with a concentration of 35-40% ethanol; and mixing the concentrated solution and the ethanol feed solution to obtain a retentate. To facilitate subsequent acid precipitation and recovery of baicalin, this invention effectively controls the solid content and ethanol concentration in the retentate through reverse osmosis treatment, resulting in lower energy consumption compared to traditional distillation.

[0069] In some embodiments, in step (6), the temperature during reverse osmosis membrane concentration is 25-50°C and the pressure is 0.6-3.0 MPa.

[0070] Regarding step (7):

[0071] In some embodiments, step (7) of heating and adjusting the pH of the retentate solution includes at least one of the following features:

[0072] The retentate was heated to 65-75℃ and the pH of the retentate was adjusted to 2.0-2.3; under specific temperature and pH conditions, baicalin was selectively precipitated.

[0073] The stirring time for crystallization is 10-25 minutes.

[0074] In some embodiments, in step (7), filtrate 2 is mixed with eluent 1 for de-alcoholization and then recycled back into the extract for the next batch of processing, thereby improving the final yield.

[0075] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0076] Example 1

[0077] A method for efficiently recovering baicalin and baicalein flavonoids from Scutellaria baicalensis root includes the following steps:

[0078] (1) Mix 3 kg of Scutellaria baicalensis root powder with 27 kg of purified water, heat at 100 °C for 3 extractions, each extraction for 50 min, combine the extracts from multiple extractions, the volume is 80.5 L, the content of Scutellaria baicalensis flavonoids in the extract is 5.920 mg / ml, of which the amount of baicalin is 4.144 mg / ml;

[0079] (2) The above extract was concentrated under reduced pressure to a solid content of 16%, heated to 70°C, and the pH of the system was adjusted to 1.6 with 1 mol / L hydrochloric acid. The mixture was stirred and precipitated for 50 min, and then filtered to obtain filtrate one and filter cake one.

[0080] (3) Mix filter cake one with purified water and slurry (the mass ratio of filter cake one to purified water is 1:27). Adjust the pH of the system to 5.3 with 0.5mol / L NaOH to obtain solution one to be treated. Add ethanol to solution one to the solid content of the system to 1.6wt% and the ethanol concentration to 27%v / v to obtain solution two to be treated.

[0081] (4) The second liquid to be treated was pumped into the AB-8 macroporous adsorption resin column at a flow rate of 1.2 BV / h (each 100 ml of resin was used to treat 68 g of the second liquid to be treated in a single batch). After adsorption, it was eluted with 28% v / v ethanol solution (the amount used was 2.6 BV of the resin volume, and the inlet flow rate was 1.0 BV / h of the resin volume) to obtain the first eluent; then it was eluted with 73% v / v ethanol solution (the amount used was 3.5 BV of the resin volume, and the inlet flow rate was 1.0 BV / h of the resin volume) to obtain the second eluent; the second eluent was dried under reduced pressure to obtain 181.3 g of Scutellaria baicalensis flavonoids with a purity of 68.2 wt%; the feed effluent and the above-mentioned first eluent were combined to obtain the third liquid to be treated.

[0082] (5) The reversed-phase chromatography column was packed with UniSil® series C18 functional group reversed-phase silica gel chromatography packing material (particle size: 40μm, pore size: 140Å). The above-mentioned solution to be treated was pumped into the reversed-phase chromatography column at a flow rate of 0.7 BV / h (the feed rate is 2.4 g of the dry weight of the solution to be treated per 100 ml of reversed-phase chromatography packing material). After the feed was completed, ethanol solution with a concentration of 31% v / v (the volume of which was 1.3 BV of the chromatography packing material) was first used. Elute with a flow rate of 0.7 BV / h (the volume of the chromatographic packing material is 0.7 BV / h), collect eluent one, then elute with a 56% v / v ethanol solution (the volume of the chromatographic packing material is 1.9 BV, the flow rate of the chromatographic packing material is 0.7 BV / h), collect eluent two; finally elute with an 81% v / v ethanol solution (the volume of the chromatographic packing material is 2.5 BV, the flow rate of the chromatographic packing material is 1.5 BV / h), collect eluent three; eluent three is combined with eluent two, eluent one is mixed with the feed effluent and then de-alcoholized and recovered into the extract of step (1);

[0083] (6) The eluent is concentrated using a reverse osmosis membrane until the permeate ethanol concentration is 38% v / v (the temperature during reverse osmosis membrane concentration is 30℃ and the pressure is 2.0 MPa). Then, the feed is topped with an ethanol solution of 38% v / v. The concentrate and feed are combined to obtain the retentate (solid content 3.6 wt%, ethanol concentration 37% v / v).

[0084] (7) Heat the above retentate to 71°C, adjust the pH to 2.1 with 1 mol / L hydrochloric acid, stir and crystallize for 18 min, and filter while hot to obtain filter cake 2 and filtrate 2; filter cake 2 is vacuum dried at 60°C to obtain 310.6 g of baicalin with a purity of 96.9 wt% and a yield of 90.2%; filtrate 2 is mixed with eluent 1 and de-alcoholized, and then recycled to the extract of step (1).

[0085] Example 2

[0086] A method for efficiently recovering baicalin and baicalein flavonoids from Scutellaria baicalensis root includes the following steps:

[0087] (1) Same as Example 1;

[0088] (2) Concentrate the above extract under reduced pressure to a solid content of 14%, heat to 75°C, adjust the pH of the system to 1.5 with 1 mol / L hydrochloric acid, stir to precipitate for 50 min, and then filter to obtain filtrate one and filter cake one. Filtrate one is reserved for other uses.

[0089] (3), (4), (5), (6), and (7) are operated in the same manner as in Example 1;

[0090] 185.3g of baicalein with a purity of 66.9wt% was obtained; 311.2g of baicalin with a purity of 96.3wt% was obtained, with a yield of 89.8%.

[0091] Example 3

[0092] A method for efficiently recovering baicalin and baicalein flavonoids from Scutellaria baicalensis root includes the following steps:

[0093] (1) The operation is the same as in Example 1;

[0094] (2) Concentrate the above extract under reduced pressure to a solid content of 18%, heat to 60°C, adjust the pH of the system to 1.8 with 1 mol / L hydrochloric acid, stir to precipitate for 50 min, and then filter to obtain filtrate one and filter cake one. Filtrate one is reserved for other uses.

[0095] (3), (4), (5), (6), and (7) are operated in the same manner as in Example 1;

[0096] 175.4g of baicalein with a purity of 68.3wt% was obtained; 308.7g of baicalin with a purity of 96.5wt% was obtained, with a yield of 89.3%.

[0097] Example 4

[0098] A method for efficiently recovering baicalin and baicalein flavonoids from Scutellaria baicalensis root includes the following steps:

[0099] (1) and (2) are operated in the same way as in Example 1;

[0100] (3) Mix filter cake one with purified water and slurry (the mass ratio of filter cake one to purified water is 1:25). Adjust the pH of the system to 5.5 with 0.5mol / LNaOH to obtain solution one to be treated. Add ethanol to solution one to the solid content of the system to 1.8wt% and the ethanol concentration to 25%v / v to obtain solution two to be treated.

[0101] (4), (5), (6), and (7) are operated in the same manner as in Example 1;

[0102] 187.2g of baicalein with a purity of 68.0wt% was obtained; 306.9g of baicalin with a purity of 96.7wt% was obtained, with a yield of 89.0%.

[0103] Example 5

[0104] A method for efficiently recovering baicalin and baicalein flavonoids from Scutellaria baicalensis root includes the following steps:

[0105] (1) and (2) are operated in the same way as in Example 1;

[0106] (3) Mix filter cake one with purified water and slurry (the mass ratio of filter cake one to purified water is 1:30). Adjust the pH of the system to 5.2 with 0.5mol / L NaOH to obtain solution one to be treated. Add ethanol to solution one to the solid content of the system to 1.3wt% and the ethanol concentration to 30%v / v to obtain solution two to be treated.

[0107] (4), (5), (6), and (7) are performed in the same manner as in Example 1; 176.5g of scutellaria baicalensis flavonoids with a purity of 69.1wt% were obtained; 311.4g of baicalin with a purity of 96.2wt% were obtained, with a yield of 89.8%.

[0108] Example 6

[0109] A method for efficiently recovering baicalin and baicalein flavonoids from Scutellaria baicalensis root includes the following steps:

[0110] (1), (2), and (3) are performed in the same manner as in Example 1;

[0111] (4) The second liquid to be treated was pumped into the D101 macroporous adsorption resin column at a flow rate of 0.5 BV / h (each 100 ml of resin was used to treat 65 g of the second liquid to be treated in a single batch). After adsorption, it was eluted with a 30% v / v ethanol solution (the amount used was 2 BV of the resin volume, and the inlet flow rate was 0.5 BV / h of the resin volume) to obtain the first eluent; then it was eluted with a 65% v / v ethanol solution (the amount used was 2.5 BV of the resin volume, and the inlet flow rate was 0.5 BV / h of the resin volume) to obtain the second eluent; the second eluent was dried under reduced pressure to obtain 178.1 g of scutellaria baicalensis flavonoids with a purity of 68.7 wt%; the feed effluent and the above-mentioned first eluent were combined to obtain the third liquid to be treated.

[0112] (5), (6), and (7) are performed in the same manner as in Example 1; 311.7g of baicalin was obtained with a purity of 96.3wt% and a yield of 90.0%.

[0113] Example 7

[0114] A method for efficiently recovering baicalin and baicalein flavonoids from Scutellaria baicalensis root includes the following steps:

[0115] (1), (2), and (3) are performed in the same manner as in Example 1;

[0116] (4) The second liquid to be treated was pumped into the AB-8 macroporous adsorption resin column at a flow rate of 2.0 BV / h (each 100 ml of resin was used to treat 72 g of the second liquid to be treated as dry matter per batch). After adsorption, it was eluted with 25% v / v ethanol solution (the amount used was 3 BV of the resin volume, and the inlet flow rate was 1.5 BV / h of the resin volume) to obtain the first eluent; then it was eluted with 80% v / v ethanol solution (the amount used was 4 BV of the resin volume, and the inlet flow rate was 1.5 BV / h of the resin volume) to obtain the second eluent; the second eluent was dried under reduced pressure to obtain 185.3 g of scutellaria baicalensis flavonoids with a purity of 67.9 wt%; the feed effluent and the above-mentioned first eluent were combined to obtain the third liquid to be treated.

[0117] (5), (6), and (7) are performed in the same manner as in Example 1; 308.0 g of baicalin was obtained with a purity of 96.6 wt% and a yield of 89.2%.

[0118] Example 8

[0119] A method for efficiently recovering baicalin and baicalein flavonoids from Scutellaria baicalensis root includes the following steps:

[0120] (1), (2), (3), and (4) are operated in the same manner as in Example 1;

[0121] (5) The reversed-phase chromatography column was packed with UniSil® series C18 functional group reversed-phase silica gel chromatography packing material (particle size: 50μm, pore size: 120Å). The above-mentioned solution to be treated was pumped into the reversed-phase chromatography column at a flow rate of 0.5 BV / h of the packing material volume (the feed rate is 2.0 g of the dry weight of the solution to be treated per 100 ml of reversed-phase chromatography packing material per batch). After the feed was completed, ethanol solution with a concentration of 30% v / v was first used (the volume of which was 1.5 BV of the chromatography packing material volume). Elute with a flow rate of 0.5 BV / h (the volume of the chromatographic packing material is 0.5 BV / h), collect eluent one, then elute with a 58% v / v ethanol solution (the volume of the chromatographic packing material is 2.0 BV, the flow rate of the chromatographic packing material is 0.5 BV / h), collect eluent two; finally elute with an 83% v / v ethanol solution (the volume of the chromatographic packing material is 2.8 BV, the flow rate of the chromatographic packing material is 1.0 BV / h), collect eluent three; eluent three is combined with eluent two, eluent one is mixed with the feed effluent and then de-alcoholized and recovered into the extract of step (1);

[0122] (6) and (7) are performed in the same manner as in Example 1; 173.5g of scutellaria baicalensis flavonoids with a purity of 69.2wt% were obtained; 311.9g of baicalin with a purity of 96.2wt% were obtained, with a yield of 89.9%.

[0123] Example 9

[0124] A method for efficiently recovering baicalin and baicalein flavonoids from Scutellaria baicalensis root includes the following steps:

[0125] (1), (2), (3), (4), and (5) are operated in the same manner as in Example 1;

[0126] (6) The eluent is concentrated using a reverse osmosis membrane until the permeate ethanol concentration is 35% v / v (the temperature during reverse osmosis membrane concentration is 50℃ and the pressure is 0.6MPa). Then, the feed is topped with an ethanol solution of 35% v / v. The concentrate and feed are combined to obtain the retentate (solid content 3wt%, ethanol concentration 35% v / v).

[0127] (7) The operation was the same as in Example 1; 181.0g of scutellaria flavonoids with a purity of 68.3wt% were obtained; 309.8g of baicalin with a purity of 96.7wt% were obtained, with a yield of 89.8%.

[0128] Example 10

[0129] A method for efficiently recovering baicalin and baicalein flavonoids from Scutellaria baicalensis root includes the following steps:

[0130] (1), (2), (3), (4), and (5) are operated in the same manner as in Example 1;

[0131] (6) The eluent is concentrated using a reverse osmosis membrane until the permeate ethanol concentration is 40% v / v (the temperature during reverse osmosis membrane concentration is 25°C and the pressure is 3.0 MPa). Then, the feed is topped with an ethanol solution of 40% v / v. The concentrate and feed are combined to obtain the retentate (solid content 4 wt%, ethanol concentration 40% v / v).

[0132] (7) The operation was the same as in Example 1; 181.6g of scutellaria flavonoids with a purity of 68.1wt% were obtained; 308.7g of baicalin with a purity of 96.8wt% were obtained, and the yield was 89.6%.

[0133] Example 11

[0134] A method for efficiently recovering baicalin and baicalein flavonoids from Scutellaria baicalensis root includes the following steps:

[0135] (1), (2), (3), (4), (5), and (6) are operated in the same manner as in Example 1;

[0136] (7) Heat the above retentate to 75°C, adjust the pH to 2.0 with 1 mol / L hydrochloric acid, stir and crystallize for 25 min, filter while hot to obtain filter cake 2 and filtrate 2; filter cake 2 is vacuum dried at 60°C to obtain baicalin; filtrate 2 is mixed with eluent 1 and de-alcoholized, and then recycled to the extract of step (1);

[0137] 181.1g of baicalein with a purity of 68.2wt% was obtained; 312.4g of baicalin with a purity of 96.2wt% was obtained, with a yield of 90.1%.

[0138] Comparative Example 1

[0139] The difference between this example and Example 1 is that in step (2), the above extract is concentrated under reduced pressure to a solid content of 10%, and the other operations are the same as in Example 1, yielding 123.2g of scutellaria baicalensis flavonoids with a purity of 58.2wt%; 298.2g of baicalin with a purity of 96.4wt%, and a yield of 86.2%.

[0140] Comparative Example 2

[0141] The difference between this example and Example 1 is that in step (2), the above extract is concentrated under reduced pressure to a solid content of 22%, and the other operations are the same as in Example 1, yielding 225.6g of scutellaria baicalensis flavonoids with a purity of 57.7wt%; 317.4g of baicalin with a purity of 94.3wt%, and a yield of 89.7%.

[0142] Comparative Example 3

[0143] The difference between this example and Example 1 is that in step (2), the temperature is raised to 50°C, and the other operations are the same as in Example 1, yielding 217.9g of scutellaria flavonoids with a purity of 59.1wt%; 316.3g of baicalin with a purity of 94.7wt%, and a yield of 89.8%.

[0144] Comparative Example 4

[0145] The difference between this example and Example 1 is that in step (2), the temperature is raised to 85°C, and the other operations are the same as in Example 1, yielding 156.5g of scutellaria baicalensis flavonoids with a purity of 59.3wt%; 304.2g of baicalin with a purity of 96.5wt%, and a yield of 88.0%.

[0146] Comparative Example 5

[0147] The difference between this example and Example 1 is that in step (2), the pH of the system is adjusted to 1.0 with 1 mol / L hydrochloric acid, and the other operations are the same as in Example 1, yielding 268.3 g of scutellaria flavonoids with a purity of 49.1 wt%; 328.9 g of baicalin with a purity of 90.9 wt%, and a yield of 89.6%.

[0148] Comparative Example 6

[0149] The difference between this example and Example 1 is that in step (2), the pH of the system is adjusted to 2.0 with 1 mol / L hydrochloric acid, and the other operations are the same as in Example 1, yielding 154.1 g of scutellaria flavonoids with a purity of 57.9 wt%; 297.4 g of baicalin with a purity of 96.8 wt%, and a yield of 86.3%.

[0150] Comparative Example 7

[0151] The difference between this example and Example 1 is that in step (3), the pH of the system was adjusted to 5.0 with 0.5 mol / L NaOH, and the other operations were the same as in Example 1, yielding 220.6 g of scutellaria flavonoids with a purity of 73.3 wt%; and 272.5 g of baicalin with a purity of 96.7 wt%, with a yield of 79.0%.

[0152] Comparative Example 8

[0153] The difference between this example and Example 1 is that in step (3), the pH of the system was adjusted to 6.0 with 0.5 mol / L NaOH, and the other operations were the same as in Example 1, yielding 157.3 g of scutellaria flavonoids with a purity of 69.1 wt%; 305.8 g of baicalin with a purity of 94.4 wt%, and a yield of 86.5%.

[0154] Comparative Example 9

[0155] The difference between this example and Example 1 is that in step (3), the solid content of the liquid to be treated is 1.0%, and the other operations are the same as in Example 1, yielding 161.3g of scutellaria baicalensis flavonoids with a purity of 68.3wt%; 293.5g of baicalin with a purity of 95.3wt%, and a yield of 83.8%.

[0156] Comparative Example 10

[0157] The difference between this example and Example 1 is that in step (3), the solid content of the liquid to be treated is 2.0%, and the other operations are the same as in Example 1, yielding 198.7g of scutellaria baicalensis flavonoids with a purity of 70.4wt%; 299.1g of baicalin with a purity of 94.7wt%, and a yield of 84.9%.

[0158] Comparative Example 11

[0159] The difference between this example and Example 1 is that in step (3), the ethanol concentration in the second solution to be treated is 20% v / v, and the other operations are the same as in Example 1, yielding 195.4g of scutellaria baicalensis flavonoids with a purity of 70.2wt%; 301.5g of baicalin with a purity of 94.8wt%, and a yield of 85.7%.

[0160] Comparative Example 12

[0161] The difference between this example and Example 1 is that in step (3), the ethanol concentration in the second solution to be treated is 35% v / v, and the other operations are the same as in Example 1, yielding 165.3g of scutellaria baicalensis flavonoids with a purity of 68.1 wt%; 296.5g of baicalin with a purity of 94.2 wt%, and a yield of 83.7%.

[0162] Comparative Example 13

[0163] The difference between this example and Example 1 is that in step (4), the concentration of the ethanol solution used to prepare the eluent is 20% v / v. Other operations are the same as in Example 1, yielding 189.5g of scutellaria baicalensis flavonoids with a purity of 72.1 wt% and 300.3g of baicalin with a purity of 95.6 wt%, with a yield of 86.1%.

[0164] Comparative Example 14

[0165] The difference between this example and Example 1 is that in step (4), the concentration of the ethanol solution used to prepare the eluent is 35% v / v. Other operations are the same as in Example 1, yielding 167.6g of scutellaria baicalensis flavonoids with a purity of 65.3wt% and 298.7g of baicalin with a purity of 95.5wt%, with a yield of 85.5%.

[0166] Comparative Example 15

[0167] The difference between this example and Example 1 is that in step (5), the concentration of the ethanol solution used to prepare the eluent is 25% v / v. Other operations are the same as in Example 1, yielding 183.5g of scutellaria baicalensis flavonoids with a purity of 68.1 wt% and 326.1g of baicalin with a purity of 92.9 wt%, with a yield of 90.8%.

[0168] Comparative Example 16

[0169] The difference between this example and Example 1 is that in step (5), the concentration of the ethanol solution used to prepare the eluent is 35% v / v. Other operations are the same as in Example 1, yielding 180.9g of scutellaria baicalensis flavonoids with a purity of 68.3wt% and 274.3g of baicalin with a purity of 96.7wt%, with a yield of 79.5%.

[0170] Comparative Example 17

[0171] The difference between this example and Example 1 is that in step (5), the concentration of the ethanol solution used to prepare the second eluent is 50% v / v. Other operations are the same as in Example 1, yielding 241.0g of scutellaria flavonoids with a purity of 73.3wt%; and 258.2g of baicalin with a purity of 96.1wt%, with a yield of 74.4%.

[0172] Comparative Example 18

[0173] The difference between this example and Example 1 is that in step (5), the concentration of the ethanol solution used to prepare the second eluent is 60% v / v. Other operations are the same as in Example 1, yielding 122.3g of scutellaria flavonoids with a purity of 64.1 wt% and 332.5g of baicalin with a purity of 90.6 wt%, with a yield of 90.3%.

[0174] Comparative Example 19

[0175] The difference between this example and Example 1 is that in step (6), the solid content of the retentate is controlled to be 2wt%, and the other operations are the same as in Example 1, yielding 181.4g of scutellaria baicalensis flavonoids with a purity of 68.1wt%; 290.5g of baicalin with a purity of 96.8wt%, and a yield of 84.3%.

[0176] Comparative Example 20

[0177] The difference between this example and Example 1 is that in step (6), the solid content of the retentate is controlled to be 6wt%, and the other operations are the same as in Example 1, yielding 181.0g of scutellaria baicalensis flavonoids with a purity of 68.3wt%; 320.4g of baicalin with a purity of 94.8wt%, and a yield of 91.1%.

[0178] Comparative Example 21

[0179] The difference between this example and Example 1 is that in step (6), the concentration of ethanol in the retentate is controlled to be 30% v / v, and the other operations are the same as in Example 1, yielding 179.3g of scutellaria flavonoids with a purity of 68.6wt%; 319.1g of baicalin with a purity of 94.9wt%, and a yield of 90.8%.

[0180] Comparative Example 22

[0181] The difference between this example and Example 1 is that in step (6), the concentration of ethanol in the retentate is controlled to be 45% v / v, and the other operations are the same as in Example 1, yielding 180.7g of scutellaria flavonoids with a purity of 68.0 wt%; 288.3g of baicalin with a purity of 96.8 wt%, and a yield of 83.7%.

[0182] Comparative Example 23

[0183] The difference between this example and Example 1 is that in step (7), the pH is adjusted to 1.0 with 1 mol / L hydrochloric acid, and the other operations are the same as in Example 1, yielding 181.4 g of scutellaria baicalensis flavonoids with a purity of 68.2 wt%; 330.1 g of baicalin with a purity of 91.9 wt%, and a yield of 90.9%.

[0184] Comparative Example 24

[0185] The difference between this example and Example 1 is that in step (7), the pH is adjusted to 2.5 with 1 mol / L hydrochloric acid, and the other operations are the same as in Example 1, yielding 183.5 g of scutellaria baicalensis flavonoids with a purity of 68.0 wt% and 265.4 g of baicalin with a purity of 97.0 wt%, with a yield of 77.2%.

[0186] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A method for efficiently extracting high-purity baicalin and baicalein flavonoids from Scutellaria baicalensis root, characterized in that, Includes the following steps: (1) After the root of Scutellaria baicalensis was crushed, it was extracted with water and filtered to obtain the extract; (2) The extract is heated and concentrated to obtain concentrate one. The pH of concentrate one is adjusted, the precipitate is stirred and then filtered to obtain filtrate one and filter cake one. (3) Mix filter cake one and purified water to make a slurry, adjust the pH of the system to obtain solution one to be treated, mix solution one to be treated with ethanol solution and heat until the solid dissolves to obtain solution two to be treated; (4) The liquid to be treated is treated by adsorption of macroporous adsorption resin. After adsorption, it is eluted by low concentration ethanol solution and high concentration ethanol solution in sequence. The elution liquid one and elution liquid two are collected respectively. The elution liquid two is dried to obtain Scutellaria baicalensis flavonoids. The feed effluent and elution liquid one are combined to obtain the liquid to be treated three. (5) The solution to be treated is pumped into a chromatographic column packed with reversed-phase chromatographic packing for separation. After the feed is completed, gradient elution is performed sequentially with the first ethanol solution, the second ethanol solution, and the third ethanol solution. Eluent 1, eluent 2, and eluent 3 are collected respectively. Eluent 3 is combined into eluent 2. (6) The eluent is concentrated using a reverse osmosis membrane to obtain a retentate with a solid content of 3-4% and an ethanol concentration of 35-40% v / v; (7) Heat the above retentate and adjust the pH, then stir to crystallize. After crystallization, filter while hot to obtain filter cake 2 and filtrate 2. Dry filter cake 2 to obtain high-purity baicalin.

2. The method for efficiently extracting high-purity baicalin and baicalein from Scutellaria baicalensis root according to claim 1, characterized in that, In step (1), the mass ratio of Scutellaria baicalensis root to water is 1:(8-10), the extraction temperature is 100℃, the extraction time is 30-60 min each time, and the number of extractions is 2-3 times.

3. The method for efficiently extracting high-purity baicalin and baicalein flavonoids from Scutellaria baicalensis root according to claim 1, characterized in that, In step (2), the solid content of the first concentrate is 14-18%; and / or the pH of the first concentrate is adjusted to 1.5-1.8; and / or the temperature when adjusting the pH of the first concentrate is 60-75℃; and / or the stirring and sedimentation time is more than 30 minutes.

4. The method for efficiently extracting high-purity baicalin and baicalein from Scutellaria baicalensis root according to claim 1, characterized in that, In step (3), the preparation of the second liquid to be treated shall include at least one of the following characteristics: The mass ratio of filter cake to purified water is 1:(25-30); The pH of the system was adjusted to 5.2-5.5; The solid content of the second liquid to be treated is 1.3-1.8 wt%, and the ethanol concentration in the second liquid to be treated is 25-30% v / v.

5. The method for efficiently extracting high-purity baicalin and baicalein from Scutellaria baicalensis root according to claim 1, characterized in that, In step (4), the macroporous adsorption resin is either D101 or AB-8; and / or during adsorption treatment, each 100ml of resin is used to treat a batch of liquid with a dry weight of 65-72g; and / or the feed flow rate during adsorption treatment is 0.5-2BV / h of the resin volume.

6. The method for efficiently extracting high-purity baicalin and baicalein from Scutellaria baicalensis root according to claim 1, characterized in that, In step (4), the concentrations of the low-concentration ethanol solution and the high-concentration ethanol solution are 25-30% v / v and 65-80% v / v, respectively; and / or the amount of the low-concentration ethanol solution used is 2-3 BV of the resin volume, and the amount of the high-concentration ethanol solution used is 2.5-4 BV of the resin volume; and / or the inlet flow rate when using the low-concentration ethanol solution and the high-concentration ethanol solution for analysis is 0.5-1.5 BV / h of the resin volume.

7. The method for efficiently extracting high-purity baicalin and baicalein from Scutellaria baicalensis root according to claim 1, characterized in that, In step (5), the reversed-phase chromatography packing material is UniSil® reversed-phase silica gel chromatography packing material with a particle size of 30-50μm and a pore size of 120-150Å; and / or the feed rate is 2-3g of the dry weight of the solution to be treated per 100ml of reversed-phase chromatography packing material per batch; and / or the feed flow rate is 0.5-1.0BV / h of the volume of the reversed-phase chromatography packing material.

8. The method for efficiently extracting high-purity baicalin and baicalein from Scutellaria baicalensis root according to claim 1, characterized in that, In step (5), the elution process includes at least one of the following characteristics: The concentrations of the first ethanol solution, the second ethanol solution, and the third ethanol solution are 30-32% v / v, 55-58% v / v, and 78-83% v / v, respectively. When using the first ethanol solution for elution, the volume of the first ethanol solution is 1.0-1.5 BV of the reversed-phase chromatography packing material, and the feed flow rate is 0.5-1.0 BV / h of the reversed-phase chromatography packing material. When using a second ethanol solution for elution, the volume of the second ethanol solution is 1.7-2.0 BV of the reversed-phase chromatography packing material, and the influent flow rate is 0.5-1.0 BV / h of the reversed-phase chromatography packing material. When using a third ethanol solution for elution, the volume of the third ethanol solution is 2.0-2.8 BV of the reversed-phase chromatography packing material, and the influent flow rate is 1.0-2.0 BV / h of the reversed-phase chromatography packing material. The eluent is mixed with the feed effluent and then de-alcoholized, before being mixed with the extract for the next batch of processing.

9. A method for efficiently extracting high-purity baicalin and baicalein from Scutellaria baicalensis root according to claim 1, characterized in that, In step (6), the process of concentrating the eluent using a reverse osmosis membrane includes: concentrating the eluent II using a reverse osmosis membrane until the ethanol concentration in the permeate is 35-40% v / v, then using a feed solution with a concentration of 35-40% ethanol, and mixing the concentrated solution and the ethanol feed solution to obtain a retentate; and / or the temperature during reverse osmosis membrane concentration is 25-50℃ and the pressure is 0.6-3.0 MPa.

10. The method for efficiently extracting high-purity baicalin and baicalein flavonoids from Scutellaria baicalensis root according to claim 1, characterized in that, In step (7), the process of heating and adjusting the pH of the retentate solution includes at least one of the following features: The retentate is heated to a temperature of 65-75℃; Adjust the pH of the retentate to 2.0-2.3; The stirring time for crystallization is 10-25 minutes; After the second filtrate is mixed with the first eluent and removed from alcohol, it is recovered into the extract for the next batch of processing.