Scutellaria baicalensis extract, and preparation method therefor and use thereof

Abstract

The present invention relates to the technical field of plant extracts, and in particular to a Scutellaria baicalensis extract, and a preparation method therefor and a use thereof. The preparation method for a Scutellaria baicalensis extract provided by the present invention achieves a baicalin yield exceeding 88% and a baicalin content over 90% in the extract. The prepared Scutellaria baicalensis extract meets quality standard requirements and can be used in traditional Chinese medicine and formulations thereof, veterinary drugs and formulations thereof, food, and daily chemical products. In addition, the method of the present invention has a simpler, greener and more efficient process, and is easily applicable to industrial production.

Description

A Scutellaria baicalensis extract, its preparation method and application

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410862428.0, filed on June 28, 2024, entitled "An Extract of Scutellaria baicalensis and its Preparation Method and Application", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of plant extract technology, and in particular to a Scutellaria baicalensis extract, its preparation method, and its application. Background Technology

[0004] Scutellaria baicalensis is a perennial herb belonging to the genus Scutellaria in the Lamiaceae family. Its dried root is used medicinally, possessing the effects of clearing heat and drying dampness, purging fire and detoxifying, stopping bleeding, and calming the fetus. Clinically, it can be used alone or in combination with other traditional Chinese medicines to treat respiratory infections, acute bacillary dysentery, and viral hepatitis. Scutellaria baicalensis extract was added to the Chinese Pharmacopoeia in 2005. To ensure that the extract meets the pharmacopoeia's quality standards, the extract obtained by water decoction requires further alkali dissolution, alcohol precipitation, secondary acid precipitation, and washing with water and alcohols of different concentrations after acid precipitation. While the refining process removes impurities, it also results in excessive loss of effective components such as baicalin. The yield of baicalin is only 50-75%, and the baicalin content of the extract obtained according to the 2020 edition of the Chinese Pharmacopoeia is generally only 85-88%, which cannot meet the requirement of 90% baicalin content for injectable preparations.

[0005] In recent years, with the proposal of the goal of high-quality development of traditional Chinese medicine, how to obtain traditional Chinese medicine products with the same quality as existing drugs or with lower harmful components in a greener and more efficient way has become an urgent technical problem to be solved.

[0006] Existing literature reports the processes for preparing Scutellaria baicalensis extracts of 85% and 90% purity (Research on Preparation Process and Quality Standards of Two Different Purpose Scutellaria baicalensis Extracts, 2016, Zheng Yanhong). The 85% baicalin content extract can be obtained simply by reflux extraction with 70% alcohol, acid adjustment, and washing with water and alcohols of different concentrations. However, the highest baicalin yield using this process is only 56.55%. The 90% baicalin content extract requires further resin purification of the 85% baicalin content extract, or by concentrating the extract, separating it with resin, and further countercurrent purification of the eluent using an ethyl acetate-n-butanol-methanol-water system. However, the yield of the 90% baicalin content extract has not been reported. Patent CN104829666B discloses a method for preparing high-purity baicalin from Scutellaria baicalensis. This method involves extracting Scutellaria baicalensis by reflux with 70% ethanol, purifying it with HPD100 macroporous resin, and then further purifying it with HSCCC separation, ultimately obtaining an extract with a baicalin content of 92%. However, this method is currently difficult to industrialize. Patent CN103417626B discloses an energy-saving method for preparing high-purity Scutellaria baicalensis extract. This method involves steps such as selection, enzyme inactivation and slicing, extraction and filtration, primary precipitation and filtration, refining and filtration, secondary precipitation and filtration, acid washing and drying, combining filtrates, concentration, drying, and residue treatment to prepare two grades of Scutellaria baicalensis extract. The first portion of the extract contains 85%-95% baicalin, but the highest yield of baicalin in the first portion is only 57.35%.

[0007] In summary, existing methods for preparing high-purity Scutellaria baicalensis extract, especially extracts with a baicalin content of over 90%, generally result in low baicalin yields or are unsuitable for industrial production. Therefore, there is a need to develop a method for preparing high-purity Scutellaria baicalensis extract that can guarantee a high yield and has potential for industrial-scale application. Summary of the Invention

[0008] This invention provides a Scutellaria baicalensis extract, its preparation method, and its application.

[0009] To develop a method for preparing high-purity Scutellaria baicalensis extract with industrial application potential, and to address the problem of low baicalin yield in existing methods, this invention optimizes the preparation method of Scutellaria baicalensis extract and discovers that programmed cooling at a specific amplitude and rate during the acid precipitation step can significantly improve the yield of baicalin while ensuring a high content of baicalin in the extract.

[0010] Specifically, the present invention provides the following technical solutions:

[0011] This invention provides a method for preparing Scutellaria baicalensis extract, the method comprising: extracting Scutellaria baicalensis with an extractant to obtain an extract, subjecting the extract to acid precipitation, and collecting the precipitate for washing.

[0012] The acid precipitation treatment includes: performing programmed cooling at a pH of 2-4, with a cooling rate of 1-3℃ / h and a cooling range of 3-10℃.

[0013] In this invention, the cooling range refers to the difference between the final temperature and the starting temperature of the programmed cooling process.

[0014] In addition to baicalin and other effective components, Scutellaria baicalensis raw materials also contain numerous known and unknown impurities. These impurities vary significantly in type and physicochemical properties, making it challenging to simultaneously ensure both the yield and purity of the target components. In the aforementioned acid precipitation process, controlling pH, cooling rate, and cooling amplitude is crucial for improving the yield and ensuring the purity of baicalin. Maintaining pH, cooling rate, and cooling amplitude within the specified ranges promotes baicalin extraction and significantly increases its yield compared to conventional acid precipitation methods. Furthermore, acid precipitation under these conditions does not increase the extraction of impurities and does not adversely affect the baicalin content in the extract, thus better ensuring the purity and other quality indicators of the obtained extract.

[0015] Preferably, the solid content of the extract is 7.5%-14.5%, and the ethanol content is 44.5%-49.5% (v / v). This invention has found that the solid content and ethanol content of the extract affect the composition of the acid precipitation system and the effectiveness of the acid precipitation treatment, thereby affecting the yield and purity of baicalin. Based on the improvements to the above-mentioned acid precipitation steps, controlling the solid content and ethanol content of the extract within the above-mentioned ranges is more conducive to improving the yield and purity of baicalin.

[0016] To control the aforementioned solid and ethanol content, it is preferable that the extract is not concentrated before acid precipitation. That is, those skilled in the art can directly obtain an extract that meets the target solid and ethanol content requirements by adjusting parameters such as the type of extractant, the solid-liquid ratio, and the number of extractions, based on the scope given in this application.

[0017] In the acid precipitation treatment described above, the temperature program involves cooling from 75-80℃ to 70-75℃.

[0018] Under the condition of ensuring the above-mentioned cooling rate and cooling range, the starting temperature of the programmed cooling is preferably 75-80℃, and the ending temperature is preferably 70-75℃.

[0019] Preferably, the pH of the extract is adjusted to 2-4, and the temperature during the acidification process is controlled at 75-80℃. The acid used for acidification can be hydrochloric acid, phosphoric acid, formic acid, etc. After acidification, the solution is subjected to programmed cooling at a rate of 1-3℃ / h, with a final temperature of 70-75℃.

[0020] Preferably, the acid precipitation treatment time is 6-10 hours.

[0021] Preferably, if the acid precipitation treatment time (i.e., 6-10 hours) is not reached when the program cools down to the endpoint temperature, the temperature is maintained at the endpoint temperature until the acid precipitation treatment ends, to ensure that the acid precipitation treatment time reaches 6-10 hours. This application utilizes acid precipitation treatment to achieve the purification effect.

[0022] In the preparation method described above, the extractant includes an aqueous solution of a short-chain alcohol.

[0023] The extractant used in this invention is an aqueous solution of short-chain alcohol or mainly an aqueous solution of short-chain alcohol. Without affecting the extraction effect, other reagents can be combined with the aqueous solution of short-chain alcohol as the extractant.

[0024] The concentration of the aqueous solution of the above-mentioned short-chain alcohol is preferably 45%-50% (v / v).

[0025] In the preparation method described above, the extraction is a continuous countercurrent extraction. This invention has found that, compared to single-extraction methods, continuous countercurrent extraction better ensures the extraction efficiency of baicalin. Furthermore, continuous countercurrent extraction significantly reduces the amount of extraction solvent used and allows for complete recovery and reuse.

[0026] Preferably, the extractant is a 45%-50% (v / v) aqueous solution of ethanol.

[0027] Preferably, the extraction material-to-liquid ratio is 1:(5-8).

[0028] The extraction is performed 3 to 5 times. Each extraction takes 0.8 to 1.2 hours. More preferably, the extraction is a double extraction (abbreviated as double extraction). Double extraction consumes less extraction reagent and can achieve sufficient enrichment of baicalin components in a small amount of extract, effectively reducing the difficulty of subsequent separation and purification.

[0029] The extraction process includes: dividing the raw materials into multiple groups; extracting the first group of raw materials N times; storing the extract from the first extraction for later use; using the extract from the second extraction as the solvent for the first extraction of the next group; using the extract from the third extraction as the solvent for the second extraction of the next group, and so on, where N is 3-5 extractions. Finally, summing up the extracts from the first extraction of each group. During the extraction process, if the number of extractions is less than 3, the baicalin extraction will be insufficient, resulting in a lower extraction yield after acid precipitation; if the number of extractions is more than 5, excessive extraction of impurities will occur, increasing the pressure of subsequent acid precipitation and reducing the purity of the baicalin product.

[0030] The extraction temperature is 75-80℃.

[0031] For the Scutellaria baicalensis raw material to be extracted, it can be short segments, thick slices, thin slices, coarse powder, or coarse powder.

[0032] After the above extraction is completed, liquid-residue separation is performed to obtain the extract. The liquid-residue separation includes: firstly, filtering the solution once using a 300-500 mesh filter cloth or filter screen to obtain a primary filtrate, and then performing precision filtration or centrifugation on the primary filtrate to obtain a clear solution, which is the extract.

[0033] In the preparation method described above, after the acid precipitation treatment is completed, filtration is performed to obtain a wet filter cake (precipitate), and the wet filter cake is then washed to remove impurities.

[0034] The above-described cleaning process involves first cleaning with water or a low-concentration alcohol solution, followed by a second cleaning with a high-concentration alcohol solution.

[0035] 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).

[0036] Preferably, during the first washing process, the amount of low-concentration alcohol solution or water used is 1.0-3.0 times (volume / mass ratio) of the weight of the wet filter cake. During the second washing process, the amount of high-concentration alcohol solution used is 1.0-3.0 times (volume / mass ratio) of the weight of the wet filter cake.

[0037] After washing and drying, the Scutellaria baicalensis extract is obtained.

[0038] Preferably, the preparation method of the present invention does not include a resin purification step.

[0039] The present invention also provides a Scutellaria baicalensis extract prepared by the method described above.

[0040] Preferably, the baicalin content of the Scutellaria baicalensis extract is not less than 90% as determined by liquid chromatography in the 2020 edition of the Chinese Pharmacopoeia.

[0041] This invention provides the application of the method described above or the Scutellaria baicalensis extract prepared by the method in the preparation of pharmaceuticals, food, veterinary drugs, feed or cosmetics.

[0042] The medicines mentioned include traditional Chinese medicine or its preparations, as well as compound preparations of traditional Chinese medicine.

[0043] The dosage forms of the medicines or veterinary drugs mentioned include, but are not limited to, oral preparations such as tablets and granules.

[0044] The beneficial effects of this invention include at least the following: The preparation method of Scutellaria baicalensis extract of this invention is stable, simple, and easy to implement. The yield of baicalin reaches over 88%, and the content of baicalin in the extract reaches over 90%. The obtained Scutellaria baicalensis extract meets the quality standards of the 2020 edition of the Chinese Pharmacopoeia and the 2020 edition of the Chinese Veterinary Pharmacopoeia. Its quality is consistent with the quality of Scutellaria baicalensis extract products prepared by the processes described in the 2020 editions of the Chinese Pharmacopoeia and the 2020 edition of the Chinese Veterinary Pharmacopoeia. It can be used in traditional Chinese medicine and its preparations, veterinary drugs and their preparations, food, and daily chemical products. Moreover, compared with existing processes that require acid precipitation-resin purification or multiple precipitation treatments, the method of this invention only performs one acid precipitation treatment, making the process simpler and significantly improving the yield of baicalin. In addition, the method of this invention uses less solvent, which can be recycled and reused, making the process greener, more efficient, and easier to apply in industrial production. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0046] Figure 1 shows the identification results of Scutellaria baicalensis extract in Example 6 of the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0048] The Scutellaria baicalensis used in the following examples and comparative examples were two-year-old plants harvested in winter in Shangzhou District, Shaanxi Province. The baicalin content was determined to be 11.04% using liquid chromatography according to the 2020 edition of the Chinese Pharmacopoeia. This detection method is only used to evaluate the theoretical value of baicalin content in raw materials, and is not suitable for industrial production due to the excessive amount of solvent used.

[0049] The countercurrent extraction mentioned in the examples is an extraction process that achieves efficient dissolution of components by continuously countercurrent flow of materials and solvents.

[0050] For programmed cooling, those skilled in the art can use conventional methods, including using programmed freezers, gradient cooling chambers, low-temperature baths, cooling circulation systems, etc. In this embodiment, a cooling circulation system is used to achieve programmed cooling.

[0051] In the following examples, the formula for calculating the total transfer rate of baicalin is as follows: Total transfer rate of baicalin = Extract product quality * Baicalin content percentage of extract product / (Raw material quality * Baicalin content percentage of raw material).

[0052] Example 1

[0053] Take Scutellaria baicalensis, cut into thick slices, mix evenly, and sample using the quartering method to determine the baicalin content (determined according to the 2020 Chinese Pharmacopoeia liquid chromatography method, used to evaluate the theoretical value of baicalin content in the raw material), moisture, and ash content, and set aside for later use. Take 100g of Scutellaria baicalensis slices into a 2000mL round-bottom flask (equipped with a reflux condenser), add 500mL of 50% (mL / mL) ethanol aqueous solution, stir magnetically, and perform continuous countercurrent extraction in a water bath at 80℃. The raw material is extracted 5 times. Specifically, a combined extraction method (referred to as combined extraction) is adopted. The raw materials are divided into five groups. The first extract of the first group of raw materials is collected and reserved. The second extract of the first group of raw materials is used as the first extractant of the second group of raw materials, and the first extract of the second group of raw materials is collected and reserved. The third extract of the first group of raw materials is used as the second extractant of the second group of raw materials, and the second extract of the second group of raw materials is used as the first extractant of the third group of raw materials, and the first extract of the third group of raw materials is collected and reserved. The fourth extract of the first group of raw materials is collected and reserved. The third extraction solvent for the second group of raw materials is used. The third extract obtained from the third extraction of the second group of raw materials is used as the second extract for the third group of raw materials. The second extract obtained from the second extraction of the third group of raw materials is used as the first extract for the fourth group of raw materials. The first extract obtained from the fourth group of raw materials is collected and kept for later use. This process is repeated in this manner. Any deficiencies are supplemented with new extraction solvent. After each group of raw materials is extracted 5 times, extraction is stopped. The first extract from the 5 batches of raw materials (the extract obtained from the first extraction of the new raw materials) is centrifuged, and the supernatant (solid content of 14.5% and ethanol content of 49.3%) is collected and stored in an 80°C water bath for later use. The pH of the supernatant was adjusted to 2.0 using hydrochloric acid, and the temperature was lowered to 70°C at a rate of 2.5°C / h for 4 hours. The solution was then kept at 70°C for another 4 hours. After filtration, the filter cake was washed successively with pure water (m / v) and 90% ethanol aqueous solution. The solution was then vacuum dried to obtain Scutellaria baicalensis extract, in which the baicalin content was 90.54% (dry basis) and the total baicalin transfer rate was 88.90%.

[0054] Example 2

[0055] Take Scutellaria baicalensis, coarsely grind it, mix it evenly, and sample it according to the quartering method to test the baicalin content, moisture, and ash content for later use. Take 100g of coarse Scutellaria baicalensis powder into a 2000mL round-bottom flask (equipped with a reflux condenser), add 800mL of 45% (mL / mL) ethanol aqueous solution, stir magnetically, and perform continuous countercurrent extraction in a water bath at 75℃. The raw material is extracted 3 times, and each extraction lasts for 1 hour. Specifically, the raw material is divided into three groups, and the extraction operation is the same as in Example 1. Each group of raw material is extracted 3 times and then no further extraction is performed. Centrifuge the extract obtained from the first extraction of the new raw material (3 batches of 1 extract), collect the supernatant (solid content of 7.5%, ethanol content of 44.6%), and store it in a water bath at 75℃ for later use. The pH of the supernatant was adjusted to 4.0 using hydrochloric acid, and the temperature was lowered to 70°C at a rate of 1°C / h for 5 hours. The solution was then kept at 70°C for another 3 hours. After filtration, the filter cake was washed successively with 50% and 95% ethanol aqueous solutions at three times its weight (m / v) of the filter cake. The solution was then vacuum dried to obtain Scutellaria baicalensis extract, in which the baicalin content was 92.85% (dry basis) and the total baicalin transfer rate was 88.20%.

[0056] Example 3

[0057] Take Scutellaria baicalensis, slice it thinly, mix it evenly, and sample it using the quartering method to test the baicalin content, moisture, and ash content for later use. Take 100g of Scutellaria baicalensis slices into a 2000mL round-bottom flask (equipped with a reflux condenser), add 600mL of 47.5% (mL / mL) ethanol aqueous solution, stir magnetically, and perform continuous countercurrent extraction in a water bath at 78℃. The raw material is extracted 4 times, and each extraction lasts for 1 hour. Specifically, the raw material is divided into four groups, and the extraction operation is the same as in Example 1. Each group of raw material is extracted 4 times and then no further extraction is performed. Centrifuge the extract from the first extraction of the new raw material (4 batches of 1 extract), collect the supernatant (solid content 11.5%, ethanol content 46.9%), and store it in a water bath at 78℃ for later use. The pH of the above solution was adjusted to 3.0 using hydrochloric acid, and the temperature was lowered to 75°C at a rate of 3°C / h for 1 hour. The solution was then kept at 75°C for 7 hours. After filtration, the filter cake was washed successively with 25% and 92% ethanol aqueous solutions at twice the weight of the filter cake (m / v). The solution was then vacuum dried to obtain Scutellaria baicalensis extract, in which the baicalin content was 91.82% (dry basis) and the total baicalin transfer rate was 88.49%.

[0058] Example 4

[0059] Take Scutellaria baicalensis, cut into thick slices, mix evenly, and sample using the quartering method to test the baicalin content, moisture, and ash content for later use. Take 100g of Scutellaria baicalensis slices into a 2000mL round-bottom flask (equipped with a reflux condenser), add 500mL of 46.5% (mL / mL) ethanol aqueous solution, stir magnetically, and perform continuous countercurrent extraction in a water bath at 80℃. The raw material is extracted 5 times, with each extraction lasting 1 hour. Specifically, the raw material is divided into five groups, and the extraction operation is the same as in Example 1. Each group of raw material is extracted 5 times and then no further extraction is performed. Centrifuge the extract from the first extraction of the new raw material (5 batches of 1 extract), collect the supernatant (solid content 14.3%, ethanol content 45.9%), and store it in an 80℃ water bath for later use. The pH of the supernatant was adjusted to 2.1 using hydrochloric acid, and the temperature was lowered to 70°C at a rate of 1.5°C / h for 6.67 hours. The mixture was then filtered, and the filter cake was successively washed with pure water (m / v) and 90% ethanol aqueous solution. The extract was then vacuum dried to obtain Scutellaria baicalensis extract, which contained 90.84% ​​baicalin (dry basis) and had a total baicalin transfer rate of 88.96%.

[0060] Example 5

[0061] Take Scutellaria baicalensis, cut into thick slices, mix evenly, and sample using the quartering method to test the baicalin content, moisture, and ash content, for later use. Take 100g of Scutellaria baicalensis slices into a 2000mL round-bottom flask (equipped with a reflux condenser), add 800mL of 49% (mL / mL) ethanol aqueous solution, stir magnetically, and perform continuous countercurrent extraction in a water bath at 77℃. The raw material is extracted 3 times, each extraction lasting 1 hour. Specifically, the raw material is divided into three groups, and the extraction operation is the same as in Example 1. Each group of raw material is extracted 3 times and then no further extraction is performed. Centrifuge the extract from the first extraction of the new raw material (3 batches of 1 batch), collect the supernatant (solid content 7.6%, ethanol content 48.6%), and store it in a 77℃ water bath for later use. The pH of the supernatant was adjusted to 2.5 using hydrochloric acid, and the temperature was lowered to 73°C at a rate of 2°C / h for 2 hours. The solution was then kept at 73°C for 8 hours. After filtration, the filter cake was washed successively with 15% ethanol aqueous solution and 94% ethanol aqueous solution at twice the weight of the filter cake (m / v). The extract was then vacuum dried to obtain Scutellaria baicalensis extract, in which the baicalin content was 90.97% (dry basis) and the total baicalin transfer rate was 88.83%.

[0062] Example 6

[0063] The Scutellaria baicalensis extracts obtained in Examples 1-3 were tested according to the 2020 edition of the Chinese Pharmacopoeia. The test indicators are as follows:

[0064] 1. Identification

[0065] The Scutellaria baicalensis extracts prepared in Examples 1-3 were identified using the method in General Chapter 0502 of the 2020 edition of the Chinese Pharmacopoeia. The identification results are shown in Figure 1. The Scutellaria baicalensis extracts prepared in Examples 1, 2, and 3 and the reference standard showed fluorescent spots of the same color at the corresponding positions in the chromatogram.

[0066] 2. Inspection

[0067] The physicochemical properties of the Scutellaria baicalensis extracts prepared in Examples 1-3 were tested according to the methods specified in the 2020 edition of the Chinese Pharmacopoeia, and the results are shown in Table 1. The results indicate that the Scutellaria baicalensis extracts prepared by the methods in Examples 1-3 meet the quality requirements specified in the Pharmacopoeia.

[0068] Table 1

[0069] Comparative Example 1

[0070] This comparative example provides a method for preparing Scutellaria baicalensis extract, the steps of which are as follows:

[0071] Take Scutellaria baicalensis, cut into thick slices, mix evenly, and sample using the quartering method to test the baicalin content, moisture, and ash content, for later use. Take 100g of Scutellaria baicalensis slices into a 2000mL round-bottom flask (equipped with a reflux condenser), add 500mL of 50% (mL / mL) ethanol aqueous solution, stir magnetically, and perform continuous countercurrent extraction in a water bath at 80℃. The raw material is extracted 5 times, each extraction lasting 1 hour. Specifically, the raw material is divided into five groups, and the extraction operation is the same as in Example 1. Each group of raw material is extracted 5 times and then no further extraction is performed. Centrifuge the extract from the first extraction of the new raw material (5 batches of 1 batch), collect the supernatant, concentrate the supernatant to a solid content of 21% and an ethanol content of 15%, and store it in an 80℃ water bath for later use. The pH of the above concentrated solution was adjusted to 2.0 using hydrochloric acid, and the temperature was lowered to 70°C at a rate of 2.5°C / h for 4 hours. The solution was then kept at 70°C for another 4 hours. After filtration, the filter cake was washed successively with pure water (m / v) and 90% ethanol aqueous solution. The solution was then vacuum dried to obtain Scutellaria baicalensis extract, in which the baicalin content was 86.82% (dry basis) and the total baicalin transfer rate was 90.08%.

[0072] Comparative Example 2

[0073] This comparative example provides a method for preparing Scutellaria baicalensis extract, the steps of which are as follows:

[0074] Take Scutellaria baicalensis, cut into thick slices, mix evenly, and sample using the quartering method to test the baicalin content, moisture, and ash content, for later use. Take 100g of Scutellaria baicalensis slices into a 2000mL round-bottom flask (equipped with a reflux condenser), add 500mL of 50% (mL / mL) ethanol aqueous solution, stir magnetically, and perform continuous countercurrent extraction in a water bath at 80℃. The raw material is extracted 5 times, each extraction lasting 1 hour. Specifically, the raw material is divided into five groups, and the extraction operation is the same as in Example 1. Each group of raw material is extracted 5 times and then no further extraction is performed. Centrifuge the extract from the first extraction of the new raw material (5 batches of 1 extract), collect the supernatant (solid content 14.5%, ethanol content 49.3%), and store it in an 80℃ water bath for later use. The pH of the supernatant was adjusted to 2.0 using hydrochloric acid, and the temperature was lowered to 40°C at a rate of 10°C / h for 4 hours. The solution was then kept at 40°C for another 4 hours. After filtration, the filter cake was washed successively with pure water (m / v) and 90% ethanol aqueous solution. The solution was then vacuum dried to obtain Scutellaria baicalensis extract, in which the baicalin content was 87.02% (dry basis) and the total baicalin transfer rate was 89.05%.

[0075] Comparative Example 3

[0076] This comparative example provides a method for preparing Scutellaria baicalensis extract, the steps of which are as follows:

[0077] Take Scutellaria baicalensis, cut into thick slices, mix evenly, and sample using the quartering method to test the baicalin content, moisture, and ash content, for later use. Take 100g of Scutellaria baicalensis slices into a 2000mL round-bottom flask (equipped with a reflux condenser), add 500mL of 50% (mL / mL) ethanol aqueous solution, stir magnetically, and perform continuous countercurrent extraction in a water bath at 80℃. The raw material is extracted 5 times, each extraction lasting 1 hour. Specifically, the raw material is divided into five groups, and the extraction operation is the same as in Example 1. Each group of raw material is extracted 5 times and then no further extraction is performed. Centrifuge the extract from the first extraction of the new raw material (5 batches of 1 extract), collect the supernatant (solid content 14.5%, ethanol content 49.3%), and store it in a water bath at 60℃ for later use. The pH of the supernatant was adjusted to 2.0 using hydrochloric acid, and the mixture was kept at 60°C for 8 hours. After filtration, the filter cake was washed successively with pure water (m / v) and 90% ethanol aqueous solution, and then vacuum dried to obtain Scutellaria baicalensis extract, in which the baicalin content was 91.67% (dry basis) and the total baicalin transfer rate was 75.57%.

[0078] Comparative Example 4

[0079] Take Scutellaria baicalensis, cut into thick slices, mix evenly, and sample using the quartering method to test the baicalin content, moisture, and ash content for later use. Take 100g of Scutellaria baicalensis slices into a 2000mL round-bottom flask (equipped with a reflux condenser), add 500mL of 46.5% (mL / mL) ethanol aqueous solution, stir magnetically, and perform continuous countercurrent extraction in a water bath at 80℃. The raw material is extracted 5 times, with each extraction lasting 1 hour. Specifically, the raw material is divided into five groups, and the extraction operation is the same as in Example 1. Each group of raw material is extracted 5 times and then no further extraction is performed. Centrifuge the extract from the first extraction of the new raw material (5 batches of 1 extract), collect the supernatant (solid content 14.3%, ethanol content 45.9%), and store it in an 80℃ water bath for later use. The pH of the supernatant was adjusted to 2.1 using hydrochloric acid, and the temperature was lowered to 70°C at a rate of 2°C / h for 5 hours. The mixture was then filtered, and the filter cake was washed successively with pure water (m / v) and 90% ethanol aqueous solution. The mixture was then vacuum dried to obtain Scutellaria baicalensis extract, in which the baicalin content was 90.14% (dry basis) and the total baicalin transfer rate was 87.43%.

[0080] Analysis revealed that in Comparative Example 1, the supernatant concentration exceeded the limits for solid content and ethanol concentration, leading to the simultaneous precipitation of impurities and a baicalin extract content below 90%. In Comparative Example 2, the endpoint temperature of the programmed cooling exceeded the limits specified in this application, resulting in excessively high levels of precipitated impurities and a baicalin extract content below 90%. In Comparative Example 3, the slow programmed cooling process was not used, and the excessively rapid cooling led to incomplete baicalin precipitation, with even less precipitation of other impurities, resulting in increased baicalin purity but decreased transfer rate. In Comparative Example 4, the short acid precipitation time resulted in insufficient baicalin precipitation, achieving a content of over 90%, but with a decreased transfer rate.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a Scutellaria extract, characterized by, The method comprises: extracting Scutellaria with an extracting agent to obtain an extracting solution, subjecting the extracting solution to acid precipitation treatment, collecting the precipitate for washing; The acid precipitation treatment comprises: subjecting to programmed cooling under the condition of pH 2-4, the cooling rate being 1-3 ℃ / h, and the cooling amplitude being 3-10 ℃.

2. The production method according to claim 1, characterized by, The solid content of the extracting solution is 7.5%-14.5%, and the ethanol content is 44.5%-49.5% (v / v). Preferably, the extracting solution is not subjected to concentration treatment before the acid precipitation treatment.

3. The production method according to claim 1 or 2, characterized by, The programmed cooling is from 75-80 ℃ to 70-75 ℃.

4. The process according to any one of claims 1 to 3, characterized in that, The acid precipitation treatment time is 6-10 h. Preferably, if the programmed cooling does not reach the acid precipitation treatment time when reaching the end temperature, the end temperature is kept for the acid precipitation treatment time.

5. The process according to any one of claims 1 to 4, characterized in that, The extracting agent comprises a short-chain alcohol aqueous solution. And / or, the extraction is continuous countercurrent extraction.

6. The production method according to claim 5, characterized by, The extracting agent is 45%-50% ethanol aqueous solution. And / or, the material-liquid ratio of the extraction is 1:(5-8). And / or, the extraction times are 3-5 times. And / or, the extraction temperature is 75-80 ℃.

7. The process according to any one of claims 1 to 6, characterized in that, The washing comprises: first washing with water or low-concentration alcohol solution, and then washing with high-concentration alcohol solution.

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

9. Scutellaria extract prepared by the method of any one of claims 1-8.

10. Use of the method of any one of claims 1-8 or the Scutellaria extract prepared by the method of any one of claims 1-8 in the preparation of pharmaceuticals, food, veterinary drugs, feed or cosmetics.

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