Preparation method for scutellaria baicalensis extract

Abstract

The present invention relates to the technical field of plant extracts, and in particular to a preparation method for a Scutellaria baicalensis extract. According to the preparation method for a Scutellaria baicalensis extract of the present invention, the yield of baicalin reaches 90% or above, the content of baicalin in the extract can be 85% or above, and the prepared Scutellaria baicalensis extract meets the quality standard requirements, and can be used in traditional Chinese medicines and preparations thereof, veterinary drugs and preparations thereof, foods, and daily chemical products. Moreover, the method of the present invention requires only a single acid precipitation treatment, involves simpler process, significantly improves the yield of baicalin, and has good prospects for application.

Description

Preparation method of scutellaria extract

[0001] Cross-reference to Related Applications

[0002] The present application claims priority to the Chinese patent application No. 202410862424.2 filed on June 28, 2024 in the China Patent Office and titled “Preparation method of scutellaria extract”, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of plant extracts, in particular to a preparation method of scutellaria extract. BACKGROUND

[0004] Scutellaria has been used as medicine for more than 2000 years. According to the Pharmacopoeia of the People's Republic of China, Scutellaria has the effects of clearing heat and drying dampness, purging fire and detoxifying, stopping bleeding, and preventing miscarriage. It is used alone or in combination with other traditional Chinese medicines to treat respiratory infections, acute bacillary dysentery, viral hepatitis, and other diseases. In recent years, with the increasing incidence of respiratory diseases, the use of Scutellaria extract has increased significantly.

[0005] Scutellaria extract was added to the Chinese Pharmacopoeia in 2005. In order to control the quality of Scutellaria extract to meet the standards of the Pharmacopoeia, the extract obtained by decocting with water needs to be subjected to acid precipitation, followed by alkaline dissolution, alcohol precipitation, secondary acid precipitation, and washing with water and different concentrations of alcohol to remove impurities. Although the purification process removes impurities, it also causes excessive loss of active ingredients such as scutellarin, resulting in a yield of scutellarin of only 50-75%. In recent years, with the proposal of high-quality development of traditional Chinese medicines, how to obtain traditional Chinese medicine products with consistent or lower hazardous components more greenly and efficiently is a problem that needs to be solved in the field of traditional Chinese medicine research.

[0006] There are existing literatures (Study on preparation technology and quality standard of two different specifications of Scutellaria extract, 2016, Zheng Yanhong) reporting the preparation process of 85% and 90% Scutellaria extract. The 85% Scutellaria extract with high content of scutellarin is prepared by reflux extraction with 70% alcohol, acid adjustment, and washing with water and different concentrations of alcohol to remove impurities. However, the results show that the highest transfer rate of scutellarin under this optimized process is only 56.55%. Patent application CN104873573A discloses the use of 50%-80% low-carbon alcohol for reflux extraction of Scutellaria. The extract is concentrated, adjusted with acid, washed with alcohol, and dried to obtain a crude product of scutellarin. The transfer rate of scutellarin is also only 35%. CN1308010C discloses the use of 30-95% ethanol for microwave extraction of Scutellaria. After concentration and complete removal of ethanol, dilution and acid precipitation are performed to obtain a product containing active ingredients of Scutellaria. According to the detection method, this method is mainly for total flavonoids in Scutellaria, and the content of scutellarin cannot reach 85% (HPLC).

[0007] In summary, the yield of baicalin prepared by the existing preparation method of Scutellaria extract with industrial application potential is still low, and the utilization rate of Scutellaria raw material needs to be improved. SUMMARY

[0008] The application provides a preparation method of Scutellaria extract.

[0009] To develop a preparation method of Scutellaria extract with industrial application potential and solve the problem of low yield of baicalin in the existing method, the preparation method of Scutellaria extract is optimized, and it is found that the yield of baicalin can be significantly improved by performing programmed cooling at a specific amplitude and rate in the acid precipitation step, while ensuring a high content of baicalin in the extract.

[0010] Specifically, the application provides the following technical solutions:

[0011] The application provides a preparation method of Scutellaria extract, which comprises the following steps: extracting Scutellaria with an extracting agent to obtain an extracting solution, performing acid precipitation treatment on the extracting solution after concentration, and collecting the precipitate for impurity washing.

[0012] The acid precipitation treatment comprises: performing programmed cooling under the condition that the pH is 2-4, the cooling rate is 5-10℃ / h, and the cooling amplitude is 15-35℃.

[0013] The Scutellaria raw material contains a large amount of known and unknown impurities in addition to effective components such as baicalin, and the substance categories and physicochemical properties of different impurities are quite different, so it is difficult to simultaneously ensure the yield and purity of the target component. In the above acid precipitation process, the control of pH, cooling rate and cooling amplitude is the key to improving the yield and ensuring the purity of baicalin. Compared with the conventional acid precipitation method, the pH, cooling rate and cooling amplitude are controlled in the above range, which can promote the extraction of baicalin and significantly improve the yield of baicalin. Meanwhile, the acid precipitation treatment under the above conditions does not increase the extraction of impurities and does not adversely affect the content of baicalin in the extract, so the quality of the prepared extract can be well ensured.

[0014] In the preparation method, the extract liquid has a solid content of 7.5%-14.5% and an ethanol content of 44.5%-49.5% (v / v), and the extract liquid is further concentrated; the concentration is to a solid content of 15%-21% (mass percent). After the concentration, the ethanol content of the extract liquid is 15%-35% (v / v). The solid content and the ethanol content of the extract liquid after the concentration affect the composition of the acid precipitation system and the effect of the acid precipitation treatment, and then affect the yield and purity of baicalin. The present application finds that, by controlling the solid content and the ethanol content of the extract liquid after the concentration in the above range, the yield and purity of baicalin are more improved. For the concentration treatment, a person skilled in the art can use a conventional method, including evaporation under reduced pressure.

[0015] In the acid precipitation treatment, the programmed cooling is from 75-80°C to 40-65°C.

[0016] Under the condition of ensuring the above-mentioned cooling rate and cooling range, the starting temperature of the programmed cooling is preferably 75-80°C, and the ending temperature is preferably 40-65°C.

[0017] Preferably, the pH of the extract liquid after the concentration is adjusted to 2-4, and the temperature of the acid adjusting process is controlled at 75-80°C. The acid used for the acid adjusting can be hydrochloric acid, phosphoric acid, formic acid, etc. After the acid adjusting, the material liquid is subjected to the programmed cooling, the cooling rate is 5-10°C / h, and the ending temperature is 40-65°C.

[0018] Preferably, the acid precipitation treatment time is 3-5h.

[0019] If the acid precipitation treatment time does not reach 3-5h when the programmed cooling reaches the ending temperature, the temperature is kept at the ending temperature until the acid precipitation treatment is completed, so as to ensure that the acid precipitation treatment time reaches 3-5h. The present application uses the acid precipitation treatment to achieve the effect of purification.

[0020] In the preparation method, the extractant includes an aqueous solution of a short-chain alcohol.

[0021] The extractant used in the present application is an aqueous solution of a short-chain alcohol or mainly an aqueous solution of a short-chain alcohol, and other reagents can be compounded as the extractant on the basis of the aqueous solution of a short-chain alcohol without affecting the extraction effect.

[0022] The concentration of the aqueous solution of a short-chain alcohol is preferably 45%-50% (v / v).

[0023] In the preparation method, the extraction is continuous countercurrent extraction. The present application finds that, compared with single extraction and other extraction methods, the continuous countercurrent extraction can better ensure the extraction efficiency of baicalin. Moreover, the continuous countercurrent extraction greatly reduces the use amount of the extraction solvent and can completely recycle and reuse the extraction solvent.

[0024] Preferably, the extraction agent is 45%-50% (v / v) aqueous ethanol solution.

[0025] Preferably, the ratio of the extracted material to the extraction agent is 1:(5-8).

[0026] The extraction is performed 3-5 times. Each extraction is performed for 0.8-1.2 h. More preferably, the extraction is a repeated extraction (referred to as a repeated extraction). The repeated extraction method consumes less extraction agent, and can achieve sufficient enrichment of baicalin in a small amount of extraction solution, thereby effectively reducing the difficulty of subsequent separation and purification.

[0027] The repeated extraction comprises the following steps: dividing the raw material into multiple groups, extracting the first group of raw material N times, saving the extraction solution obtained by the first extraction for later use, using the extraction solution obtained by the second extraction as the extraction solvent for the first extraction of the next group, using the extraction solution obtained by the third extraction as the extraction solvent for the second extraction of the next group, and so on, wherein N is 3-5. Finally, the extraction solution obtained by the first extraction of each group is combined. If the extraction is performed less than 3 times, the extraction of baicalin is insufficient, and the yield of baicalin after acid precipitation is reduced. If the extraction is performed more than 5 times, too many impurities are extracted, the pressure of subsequent acid precipitation is increased, and the purity of baicalin product is reduced.

[0028] The extraction is performed at a temperature of 75-80°C.

[0029] The raw material of Scutellaria baicalensis Georgi for extraction can be short segments, thick slices, thin slices, the coarsest powder, or coarse powder.

[0030] After the above extraction is completed, liquid residue separation is performed to obtain the extraction solution, which comprises the following steps: first, one filtration is performed using a 300-500 mesh filter cloth or filter screen to obtain a one-time filtration solution, and then the one-time filtration solution is subjected to precision filtration to obtain a clear solution, which is the extraction solution.

[0031] In the above preparation method, after the acid precipitation is completed, the wet filter cake is obtained by filtration, and the wet filter cake is subjected to impurity washing.

[0032] The above impurity washing comprises the following steps: first, one impurity washing is performed using water or a low-concentration alcohol solution, and then two impurity washings are performed using a high-concentration alcohol solution.

[0033] The low-concentration alcohol solution is an aqueous ethanol solution with a concentration greater than 0 and less than or equal to 50% (v / v). The high-concentration alcohol solution is an aqueous ethanol solution with a concentration of 90%-95% (v / v).

[0034] Preferably, in the one impurity washing, the amount of the low-concentration alcohol solution or water is 1.0-3.0 times (volume / mass ratio) the weight of the wet filter cake. In the two impurity washings, the amount of the high-concentration alcohol solution is 1.0-3.0 times (volume / mass ratio) the weight of the wet filter cake.

[0035] After the washing and impurity removal, drying is performed to obtain the Scutellaria extract.

[0036] Preferably, the preparation method does not comprise a resin purification step.

[0037] The present application also provides the Scutellaria extract prepared by the above method.

[0038] Preferably, the Scutellaria extract has a content of baicalin of not less than 85% according to the 2020 Chinese Pharmacopoeia liquid chromatography method.

[0039] The present application provides the use of the above method or the Scutellaria extract prepared by the method in the preparation of a pharmaceutical product, a food, a veterinary drug, a feed or a cosmetic.

[0040] The pharmaceutical product comprises a traditional Chinese medicine or a preparation thereof, and also comprises a composite preparation of a traditional Chinese medicine.

[0041] The dosage form of the pharmaceutical product or the veterinary drug comprises, but is not limited to, a tablet, a granule and the like oral preparation.

[0042] The present application has at least the following beneficial effects: the preparation method of the Scutellaria extract of the present application is stable and simple, the yield of baicalin reaches more than 90%, the content of baicalin in the extract can reach more than 85%, the prepared Scutellaria extract meets the quality standard requirements of the 2020 edition of the Chinese Pharmacopoeia and the 2020 edition of the Chinese Veterinary Pharmacopoeia, the quality is consistent with the quality of the Scutellaria extract prepared by the process recorded in the 2020 edition of the Chinese Pharmacopoeia and the 2020 edition of the Chinese Veterinary Pharmacopoeia, the physical properties and the extract prepared by the pharmacopoeia process are consistent when applied to tablets, granules and oral preparations, and can be applied to traditional Chinese medicines and preparations thereof, veterinary drugs and preparations thereof, foods and daily chemical products. Moreover, compared with the two-time acid precipitation treatment required by the pharmacopoeia process and the existing acid precipitation-resin refining process, the method of the present application only performs one-time acid precipitation treatment, the process is simpler, and the yield of baicalin is greatly improved. In addition, the solvent used in the method of the present application is less, and can be recycled and reused, and the process is more green and efficient. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without any creative effort.

[0044] Figure 1 is the state of each batch of Scutellaria baicalensis Georgi raw material in Example 4 of the present application.

[0045] Figure 2 is a similarity analysis of the Scutellaria extract prepared from each batch of Scutellaria raw material in Example 4 of the present application and the Scutellaria extract meeting the pharmacopoeia standard, wherein R is a standard curve fitting the fingerprint of 21 batches of Scutellaria extract, S1-S15 are Scutellaria extracts prepared from 15 batches of Scutellaria raw material; the horizontal coordinate is time (min) and the vertical coordinate is signal (mV). DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0047] The Scutellaria used in the following Examples 1-3 and Comparative Examples is 2-year-old winter-harvested Scutellaria from Shangzhou District, Shaanxi Province, and the content of baicalin detected according to the liquid chromatography method in the 2020 Chinese Pharmacopoeia is 11.04%. This detection method is only used to evaluate the theoretical value of the baicalin content in the raw material, and is not suitable for industrial production due to the excessive amount of solvent used.

[0048] The countercurrent extraction mentioned in the examples is an extraction process that realizes efficient dissolution of components through continuous countercurrent flow of materials and solvents.

[0049] For programmed cooling, those skilled in the art can use conventional methods, including using a programmed freezer, a gradient cooling box, or using a low-temperature bath, a cooling circulation system, etc. to realize programmed cooling. In the present application, a cooling circulation system is used to realize programmed cooling.

[0050] In the following examples, the calculation formula of the total transfer rate of baicalin is as follows: total transfer rate of baicalin = product mass of extract * content ratio of baicalin in extract / (raw material mass * content ratio of baicalin in raw material).

[0051] Example 1

[0052] The present embodiment provides a preparation method of Scutellaria extract, the steps of which are as follows:

[0053] Take Scutellaria, cut thick slices, mix evenly, take sample for detection of baicalin content (detection according to 2020 Chinese Pharmacopoeia liquid chromatography method, used to evaluate the theoretical value of baicalin content in raw materials), moisture, ash, for standby. Take 100 g of Scutellaria slices into a 2000 mL round bottom flask (configure a reflux condenser), add 500 mL of 50% (mL / mL) ethanol aqueous solution, magnetically stir, water bath at 75°C for continuous countercurrent extraction, and the raw material is extracted for 5 times, each time for 1 h. Specifically, the extraction is carried out in a nested extraction (referred to as nested extraction) manner, and the raw material is divided into five groups. The 1st extract of the 1st extraction of the 1st group of raw material is taken out for standby; the 2nd extract of the 1st extraction of the 1st group of raw material is used as the 1st extraction agent for the 2nd group of raw material, and the 1st extract of the 2nd group of raw material is taken out for standby; the 3rd extract of the 1st extraction of the 1st group of raw material is used as the 2nd extraction agent for the 2nd group of raw material, and the 2nd extract of the 2nd extraction agent of the 2nd group of raw material is used as the 1st extraction agent for the 3rd group of raw material, and the 1st extract of the 3rd group of raw material is taken out for standby; the 4th extract of the 1st extraction of the 1st group of raw material is used as the 3rd extraction agent for the 2nd group of raw material, and the 3rd extract of the 3rd extraction agent of the 2nd group of raw material is used as the 2nd extraction agent for the 3rd group of raw material, and the 2nd extract of the 2nd extraction agent of the 3rd group of raw material is used as the 1st extraction agent for the 4th group of raw material, and the 1st extract of the 4th group of raw material is taken out for standby; and so on. The insufficient part is supplemented with new extraction solvent, and each group of raw material is extracted for 5 times, then the 1st extract (the extraction liquid obtained by the first time extraction of the new raw material) of the 5 pots is centrifuged, and the supernatant is collected. The supernatant is concentrated to a solid content of 21% and an ethanol content of 15%, and then stored in a 75°C water bath for standby. The above concentrated liquid is adjusted to pH 2.0 with hydrochloric acid, cooled to 40°C at 10°C / h, takes 3.5h, filtered, and the filter cake is washed with 2 times (m / v) of pure water and 90% ethanol aqueous solution, respectively, and vacuum dried to obtain Scutellaria extract, wherein the baicalin content is 85.75% (dry basis), and the total transfer rate of baicalin is 92.50%.

[0054] Example 2

[0055] The present embodiment provides a preparation method of Scutellaria extract, which comprises the following steps:

[0056] Take Scutellaria, coarse grinding, mix evenly, take sample detection baicalin content, moisture, ash, for standby. Take 100 g of Scutellaria coarse powder into a 2000 mL round bottom flask (configure reflux condenser), add 800 mL of 45% (mL / mL) ethanol aqueous solution, magnetic stirring, water bath 80℃ continuous countercurrent extraction, the extraction times of raw material is 3 times, each extraction 1 h. Specifically, the raw material is divided into three groups, the same as the operation of example 1, each group of raw material is extracted 3 times, then the 3 pots 1 liquid (the first extraction liquid of the new raw material) is centrifuged, and the supernatant is collected. The supernatant is concentrated to a solid content of 15%, and the ethanol content is 35%, then it is stored in a 80℃ water bath, and used. Use hydrochloric acid to adjust the pH of the above concentrated liquid to 4.0, cool to 65℃ at 5℃ / h, take 3h, and continue to incubate at 65℃ for 2h, filter, and then use the filter cake weight 2 times (m / v) of 50%, 95% ethanol aqueous solution for elution, vacuum drying to obtain Scutellaria extract, wherein the baicalin content is 88.98% (dry basis), and the total transfer rate of baicalin is 90.08%.

[0057] Example 3

[0058] The present embodiment provides a preparation method of Scutellaria extract, which comprises the following steps:

[0059] Take Scutellaria, cut into thin slices, mix evenly, take sample detection baicalin content, moisture, ash, for standby. Take 100 g of Scutellaria slice into a 2000 mL round bottom flask (configure reflux condenser), add 600 mL of 47.5% (mL / mL) ethanol aqueous solution, magnetic stirring, water bath 78℃ continuous countercurrent extraction, the extraction times of raw material is 4 times, each extraction 1 h. Specifically, the raw material is divided into four groups, the same as the operation of example 1, each group of raw material is extracted 4 times, then the 4 pots 1 liquid (the first extraction liquid of the new raw material) is centrifuged, and the supernatant is collected. The supernatant is concentrated to a solid content of 17.2%, and the ethanol content is 25%, then it is stored in a 78℃ water bath, and used. Use hydrochloric acid to adjust the pH of the above concentrated liquid to 3.0, cool to 55℃ at 7.5℃ / h, take 3.07h, filter, and then use the filter cake weight 2 times (m / v) of 25%, 92% ethanol aqueous solution for elution, vacuum drying to obtain Scutellaria extract, wherein the baicalin content is 87.61% (dry basis), and the total transfer rate of baicalin is 91.07%.

[0060] Example 4

[0061] The present embodiment uses the method of example 3 above to prepare Scutellaria extract with different batches of Scutellaria from different producing areas, which comprises the following steps:

[0062] From Shanxi, Shaanxi, Gansu and other producing areas, 5 batches of Scutellaria with different growth years are collected from each producing area, totaling 15 batches of Scutellaria.

[0063] The information of the Scutellariae Radix is shown in Table 1, and the state of the Scutellariae Radix of each batch is shown in Figure 1.

[0064] Table 1

[0065] The Scutellariae Radix of each batch was used to prepare the Scutellariae Radix extract according to the following steps:

[0066] The Scutellariae Radix was cut into thin slices, mixed uniformly, and sampled for detection of baicalin content, moisture, and ash content according to the four-part method, for standby. 100 g of the Scutellariae Radix slices were taken into a 2000 mL round-bottom flask (with a reflux condenser), 600 mL of 47.5% (mL / mL) ethanol aqueous solution was added, and magnetic stirring was performed with water bath at 78 ℃ for continuous countercurrent extraction, with 4 times of extraction of the raw material, 1 h for each time. Specifically, the raw material was divided into four groups, and the extraction was performed according to the extraction operation of Example 1, and after 4 times of extraction of each group of raw material, the extraction was stopped, and then the 4 pots of 1 material liquid (the extract obtained by first extraction of the new raw material) were centrifuged to collect the supernatant. After the supernatant was concentrated to a solid content of 17.2% and an ethanol content of 25%, it was stored in a water bath at 78 ℃ for standby. The above concentrated material liquid was adjusted to pH 3.0 with hydrochloric acid, and the temperature was lowered to 55 ℃ at a rate of 7.5 ℃ / h, which took 3.07 h, and then filtered. The filter cake was sequentially washed with 25% and 92% ethanol aqueous solution at a ratio of 2 times (m / v) of the filter cake weight, and then vacuum dried to obtain the Scutellariae Radix extract S1-S15.

[0067] Twenty-one batches of commercially available Scutellariae Radix extract meeting the standards of the 2020 edition of the Chinese Pharmacopoeia were collected, with a baicalin content of 85.1-88.2%, and the standard curve was fitted with the fingerprint of the 21 batches of Scutellariae Radix extract. Similarity analysis was performed on the extract S1-S15 prepared from each batch of Scutellariae Radix in Table 1 and the standard curve. The results (Figure 2) showed that the similarity of the Scutellariae Radix extract obtained in Example 4 and the commercially available Scutellariae Radix extract meeting the standards of the Pharmacopoeia was 0.999-1.000, indicating that the Scutellariae Radix extract prepared by the method of the present application met the standards of the Pharmacopoeia.

[0068] Example 5

[0069] The present example provides a method for preparing a Scutellariae Radix extract, which comprises the following steps:

[0070] Take Scutellaria, cut thick slices, mix evenly, take sample by four-part method to detect baicalin content, moisture, ash, for standby. Take 100 g of Scutellaria slices into a 2000 mL round-bottom flask (configure reflux condenser), add 800 mL of 49.5% (mL / mL) ethanol aqueous solution, magnetic stirring, water bath 70℃ continuous countercurrent extraction, the extraction times of raw material is 4 times, each extraction 1 h. Specifically, the raw material is divided into four groups, the same as the operation of example 1, each group of raw material is extracted 4 times, then the 4 pots 1 liquid (the extract liquid obtained by the first extraction of new raw material) is centrifuged, and the supernatant is collected. After the supernatant is concentrated to a solid content of 21% and an ethanol content of 15%, it is stored in a 70℃ water bath for standby. Use hydrochloric acid to adjust the pH of the above concentrated liquid to 2.1, and cool to 40℃ at a rate of 10℃ / h, which takes 3h, filter, and use 3 times (m / v) of pure water and 90% ethanol aqueous solution to rinse the filter cake in sequence, and vacuum dry to obtain Scutellaria extract, wherein the baicalin content is 86.13% (dry basis), and the total transfer rate of baicalin is 92.29%.

[0071] Comparative Example 1

[0072] This comparative example provides a preparation method of Scutellaria extract, the steps of which are as follows:

[0073] Take Scutellaria, cut thick slices, mix evenly, take sample by four-part method to detect baicalin content, moisture, ash, for standby. Take 100 g of Scutellaria slices into a 2000 mL round-bottom flask (configure reflux condenser), add 800 mL of 49.5% (mL / mL) ethanol aqueous solution, magnetic stirring, water bath 70℃ continuous countercurrent extraction, the extraction times of raw material is 4 times, each extraction 1 h. Specifically, the raw material is divided into four groups, the same as the operation of example 1, each group of raw material is extracted 4 times, then the 4 pots 1 liquid (the extract liquid obtained by the first extraction of new raw material) is centrifuged, and the supernatant is collected. After the supernatant is concentrated to a solid content of 21% and an ethanol content of 15%, it is stored in a 70℃ water bath for standby. Use hydrochloric acid to adjust the pH of the above concentrated liquid to 2.1, and cool to 40℃ at a rate of 10℃ / h, which takes 3h, filter, and use 3 times (m / v) of pure water and 90% ethanol aqueous solution to rinse the filter cake in sequence, and vacuum dry to obtain Scutellaria extract, wherein the baicalin content is 86.13% (dry basis), and the total transfer rate of baicalin is 92.29%.

[0074] Comparative Example 2

[0075] This comparative example provides a preparation method of Scutellaria extract, the steps of which are as follows:

[0076] Take Scutellaria, cut into thin slices, mix evenly, take sample according to the four-part method to detect baicalin content, moisture, ash, and reserve. Take 100 g of Scutellaria powder into a 2000 mL round-bottom flask (configure a reflux condenser), add 600 mL of 47.5% (mL / mL) ethanol aqueous solution, magnetically stir, and perform continuous countercurrent extraction in a water bath at 78°C. The raw material is extracted 4 times, each time for 1 h. Specifically, the raw material is divided into four groups, and the extraction operation is the same as that of Example 1. After each group of raw material is extracted 4 times, it is no longer extracted. Then, the 4 pots of 1 material liquid (the extract obtained by the first extraction of the new raw material) are centrifuged, and the supernatant is collected. The supernatant is concentrated to a solid content of 25.0% and an ethanol content of 5%, and then stored in a 78°C water bath for later use. Adjust the pH of the above concentrated material liquid to 3.0 using hydrochloric acid, and cool it to 55°C at a rate of 7.5°C / h, which takes 3.07 h. Filter the solution, and then use a filter cake weight of 2 times (m / v) of 25% and 92% ethanol aqueous solution to rinse the filter cake, respectively. Vacuum dry to obtain a Scutellaria extract, wherein the baicalin content is 75.25% (dry basis), and the total transfer rate of baicalin is 93.70%.

[0077] Comparative Example 3

[0078] This comparative example provides a preparation method of a Scutellaria extract, the steps of which are as follows:

[0079] Take Scutellaria, cut into thin slices, mix evenly, take sample according to the four-part method to detect baicalin content, moisture, ash, and reserve. Take 100 g of Scutellaria powder into a 2000 mL round-bottom flask (configure a reflux condenser), add 600 mL of 47.5% (mL / mL) ethanol aqueous solution, magnetically stir, and perform continuous countercurrent extraction in a water bath at 78°C. The raw material is extracted 4 times, each time for 1 h. Specifically, the raw material is divided into four groups, and the extraction operation is the same as that of Example 1. After each group of raw material is extracted 4 times, it is no longer extracted. Then, the 4 pots of 1 material liquid (the extract obtained by the first extraction of the new raw material) are centrifuged, and the supernatant is collected. The supernatant is concentrated to a solid content of 25.0% and an ethanol content of 5%, and then stored in a 78°C water bath for later use. Adjust the pH of the above concentrated material liquid to 3.0 using hydrochloric acid, and cool it to 55°C at a rate of 7.5°C / h, which takes 3.07 h. Filter the solution, and then use a filter cake weight of 2 times (m / v) of 25% and 92% ethanol aqueous solution to rinse the filter cake, respectively. Vacuum dry to obtain a Scutellaria extract, wherein the baicalin content is 75.25% (dry basis), and the total transfer rate of baicalin is 93.70%.

[0080] Comparative Example 4

[0081] This comparative example provides a preparation method of a Scutellaria extract, the steps of which are as follows:

[0082] Take Scutellaria, cut into thin slices, mix evenly, take sample by four division method to detect baicalin content, moisture, ash, for standby. Take 100 g of Scutellaria slices into a 2000 mL round bottom flask (configure reflux condenser), add 600 mL of 47.5% (mL / mL) ethanol aqueous solution, magnetic stirring, water bath 78℃ continuous countercurrent extraction, the number of raw material extraction is 4 times, each time 1 h. Specifically, the raw material is divided into four groups, and the operation of the same example 1 is repeated. After each group of raw material is extracted 4 times, it is not extracted any more. Then, the 4 pots 1 liquid (the extract obtained by the first extraction of the new raw material) is centrifuged, and the supernatant is collected. The supernatant is concentrated to an ethanol content of 25% and a solid content of 10%, and is stored in a 78℃ water bath for standby. The above concentrated liquid is adjusted to pH 3.0 with hydrochloric acid, and is cooled to 55℃ at a rate of 7.5℃ / h, which takes 3.07 h. Filtration is performed, and the filter cake is first washed with 25% and then with 92% ethanol aqueous solution, which is 2 times (m / v) the weight of the filter cake. Vacuum drying gives Scutellaria extract, wherein the baicalin content is 87.63% (dry basis), and the total transfer rate of baicalin is 80.80%.

[0083] Comparative Example 5

[0084] This comparative example provides a preparation method of Scutellaria extract, the steps of which are as follows:

[0085] Take Scutellaria, cut into thin slices, mix evenly, take sample by four division method to detect baicalin content, moisture, ash, for standby. Take 100 g of Scutellaria slices into a 2000 mL round bottom flask (configure reflux condenser), add 600 mL of 47.5% (mL / mL) ethanol aqueous solution, magnetic stirring, water bath 78℃ continuous countercurrent extraction, the number of raw material extraction is 4 times, each time 1 h. Specifically, the raw material is divided into four groups, and the operation of the same example 1 is repeated. After each group of raw material is extracted 4 times, it is not extracted any more. Then, the 4 pots 1 liquid (the extract obtained by the first extraction of the new raw material) is centrifuged, and the supernatant is collected. The supernatant is concentrated to an ethanol content of 25% and a solid content of 10%, and is stored in a 78℃ water bath for standby. The above concentrated liquid is adjusted to pH 3.0 with hydrochloric acid, and is cooled to 55℃ at a rate of 7.5℃ / h, which takes 3.07 h. Filtration is performed, and the filter cake is first washed with 25% and then with 92% ethanol aqueous solution, which is 2 times (m / v) the weight of the filter cake. Vacuum drying gives Scutellaria extract, wherein the baicalin content is 87.63% (dry basis), and the total transfer rate of baicalin is 80.80%.

[0086] Comparative Example 6

[0087] This comparative example provides a preparation method of Scutellaria extract, the steps of which are as follows:

[0088] Take Huangqi, cut into thin slices, mix evenly, take sample for detection of baicalin content, moisture, ash content by four-part method, for standby. Take 100 g of Huangqi slices into a 2000 mL round-bottom flask (configure reflux condenser), add 600 mL of 47.5% (mL / mL) ethanol aqueous solution, magnetically stir, and continuously perform countercurrent extraction in a water bath at 78°C. The raw material is extracted 4 times, with each extraction lasting 1 h. Specifically, the raw material is divided into four groups, and the extraction is performed in the same way as in Example 1. After each group of raw material is extracted 4 times, it is no longer extracted. Then, the 4 pots of 1 material liquid (the extract obtained by first extraction of new raw material) are centrifuged, and the supernatant is collected. The supernatant is concentrated to a solid content of 17.2% and an ethanol content of 25%, and then stored in a water bath at 78°C for standby. The above concentrated material liquid is adjusted to pH 3.0 with hydrochloric acid, and the temperature is lowered to 55°C at a rate of 10°C / h, which takes 2.3 h. Filtration is performed, and the filter cake is first washed with 25% and then with 92% ethanol aqueous solution, which is 2 times (m / v) the weight of the filter cake. Vacuum drying is performed to obtain Huangqi extract, wherein the baicalin content is 85.97% (dry basis), and the total transfer rate of baicalin is 89.24%.

[0089] Analysis shows that, in Comparative Example 1, the slow program cooling process is not used, and the low acid precipitation standing temperature leads to excessive impurities being precipitated. The precipitation of baicalin is greatly affected by the impurities, so the purity of baicalin is reduced and the transfer rate is increased. In Comparative Example 2, the concentration of the supernatant exceeds the limited range of solid content and ethanol concentration, leading to the synchronous precipitation of impurities, and the content of baicalin extract is less than 85%. In Comparative Example 3, the final temperature of the program cooling is lower than the limited range of the present application, and the amount of impurities precipitated is too high, leading to the content of baicalin extract being less than 85%. In Comparative Example 4, the concentration of the supernatant does not reach the limited range of solid content and ethanol concentration, and the amount of impurities precipitated is less, leading to the purity of baicalin being increased and the transfer rate being decreased. In Comparative Example 5, the slow program cooling process is not used, and the high acid precipitation standing temperature and the fast cooling rate lead to incomplete precipitation of baicalin and less precipitation of other impurities, leading to the purity of baicalin being increased and the transfer rate being decreased. In Comparative Example 6, the cooling speed is fast and the acid precipitation time is short, leading to incomplete precipitation of baicalin. The content can reach more than 85%, but the transfer rate is reduced.

[0090] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing Scutellaria baicalensis extract, characterized in that, The method includes: extracting Scutellaria baicalensis with an extractant to obtain an extract, concentrating the extract and then subjecting it to acid precipitation, collecting the precipitate and washing it to remove impurities; The acid precipitation treatment includes: performing programmed cooling at a pH of 2-4, with a cooling rate of 5-10℃ / h and a cooling range of 15-35℃.

2. The preparation method according to claim 1, characterized in that, The concentration is such that the solid content is 15%-21%; And / or, the ethanol content in the concentrated extract is 15-35% (v / v).

3. The preparation method according to claim 1 or 2, characterized in that, The cooling process involves reducing the temperature from 75-80℃ to 40-65℃. Preferably, the acid precipitation treatment time is 3-5 hours; More preferably, if the acid precipitation treatment time has not reached 3-5 hours when the program cools down to the final temperature, the final temperature is maintained until the acid precipitation treatment is completed.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The extractant comprises an aqueous solution of short-chain alcohols; And / or, the extraction is a continuous countercurrent extraction.

5. The preparation method according to claim 4, characterized in that, The extractant is a 45%-50% (v / v) aqueous solution of ethanol.

6. The preparation method according to claim 4 or 5, characterized in that, The extraction material-to-liquid ratio is 1:(5-8); And / or, the number of extractions is 3 to 5; And / or, the extraction temperature is 75-80℃.

7. The preparation method according to any one of claims 1 to 6, characterized in that, The impurity washing process involves first washing with water or a low-concentration alcohol solution, followed by a second washing with a high-concentration alcohol solution.

8. The preparation method according to claim 7, characterized in that, The low-concentration alcohol solution is an aqueous ethanol solution with a concentration greater than 0 and less than or equal to 50% (v / v); And / or, the high-concentration alcohol solution is a 90%-95% (v / v) aqueous ethanol solution.

9. The Scutellaria baicalensis extract prepared by the method according to any one of claims 1 to 8.

10. The use of the Scutellaria baicalensis extract prepared by the method according to any one of claims 1 to 8 in the preparation of pharmaceuticals, food, veterinary drugs, feed or cosmetics.

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