A method for constructing a scutellaria baicalensis stem and leaf fingerprint and application thereof

Abstract

The application discloses a method for constructing a Scutellaria baicalensis Georgi stem and leaf fingerprint and application thereof, and belongs to the technical field of drug quality control. The method comprises the following steps: preparing standard sample solutions of wild baicalin, baicalin, taxifolin and isofraxidin; preparing a Scutellaria baicalensis Georgi stem and leaf sample solution; detecting under specific conditions by high performance liquid chromatography, taking standard sample chromatographic peaks as references, and formulating a standard fingerprint of the Scutellaria baicalensis Georgi stem and leaf, wherein the relative standard deviation of the relative retention time is not more than ±20%. The method has high precision, good stability and excellent repeatability, can realize effective separation of four kinds of flavone components within 35 minutes, and comprehensively reflects the quality characteristics of the Scutellaria baicalensis Georgi stem and leaf. The application also provides application of the fingerprint in quality analysis of Scutellaria baicalensis Georgi stem and leaf medicinal materials and extracts, and provides reliable technical support for resource development and quality control of the Scutellaria baicalensis Georgi stem and leaf.

Description

Technical Field

[0001] This invention relates to the construction and application of a fingerprint spectrum of Scutellaria baicalensis stems and leaves, belonging to the field of drug quality control technology. Background Technology

[0002] Scutellaria baicalensis stems and leaves, as the non-medicinal parts of Scutellaria baicalensis with a long history and significant medicinal effects, have similar types of active ingredients as Scutellaria baicalensis, but their content differs significantly from that of Astragalus membranaceus. To increase the resource utilization rate of Scutellaria baicalensis stems and leaves, they are usually processed to extract their effective components for drug preparation. The most common pretreatment method for extracting the effective components from Scutellaria baicalensis stems and leaves is reflux extraction. Specifically, 1g of Scutellaria baicalensis stem and leaf powder is accurately weighed, refluxed with 25mL of 60% ethanol for 1 hour, the weight loss is made up, and an appropriate amount of extract is transferred to an evaporating dish. The extract is concentrated and evaporated to dryness in a 60℃ water bath, dissolved in chromatographic grade methanol, transferred to a 25ml volumetric flask, sealed tightly, sonicated, shaken well, and filtered through a 0.22μm filter membrane to obtain the active components of Scutellaria baicalensis stems and leaves.

[0003] Currently, because Scutellaria baicalensis stems and leaves are not included in the Chinese Pharmacopoeia or the Chinese Veterinary Pharmacopoeia as traditional Chinese medicine, there are no relevant standards for identifying its marker components. Current domestic and international testing of Scutellaria baicalensis stems and leaves generally uses baicalin or total flavonoids as indicators. The main drawbacks of this method are: insufficient comprehensiveness—flavonoid components are complex and diverse, and a single indicator cannot cover the overall quality. For example, dihydroquercetin (tacutanein) has strong anti-inflammatory activity, but it is easily overlooked at low concentrations. Detection is difficult: existing technologies struggle to simultaneously separate multiple components. For example, when gradient elution conditions are not optimized, the separation of baicalin and dihydroquercetin is poor. Methodological deficiencies: existing methods lack repeatability and precision validation.

[0004] With the increasing popularity of Scutellaria baicalensis stem and leaf resource development, the establishment of multi-index, high-sensitivity fingerprinting technology has become an essential need for the industry. Summary of the Invention

[0005] The purpose of this invention is to provide a method for constructing and applying fingerprint spectroscopy of Scutellaria baicalensis stems and leaves. This invention has high precision, good stability and repeatability, and can more comprehensively and effectively detect the main active components of Scutellaria baicalensis stems and leaves, laying a technical foundation for the quality control of Scutellaria baicalensis stems and leaves.

[0006] To address the shortcomings of existing technologies that rely solely on single indicators such as baicalin or total flavonoids, this invention constructs a fingerprint spectrum covering four key flavonoid components (baicalin, baicalin, piperidin, and isoxafen), solving the problem of "no standard to follow" caused by the fact that Scutellaria baicalensis stems and leaves are not included in the pharmacopoeia, and promoting the high-value development of non-medicinal parts.

[0007] The method for constructing the stem and leaf fingerprint spectrum of Scutellaria baicalensis provided by the present invention includes the following steps:

[0008] S1. Preparation of standard solutions: Weigh the standards of baicalin, scutellarin, piperidin, and isoxafen, and dilute with methanol to 5-474 μg / mL, 18-546 μg / mL, 17-524 μg / mL, and 22-670 μg / mL, respectively; perform liquid chromatography to obtain the standard comparison peaks; S2. Sample solution preparation: Weigh the powder of Scutellaria baicalensis stems and leaves, extract with ethanol by reflux, and then make up to volume with methanol; perform liquid chromatography to obtain the standard fingerprint spectrum; S3. Standard fingerprint spectrum development: Based on the retention time of the chromatographic peak of the standard comparison peak, calculate the relative retention time of other common chromatographic peaks in the standard fingerprint spectrum, and the relative standard deviation shall not exceed ±20%.

[0009] In steps S1 and S2, the liquid chromatography detection conditions are as follows: Column: Waters Xselect HSS T3 5μm, packed with octadecylsilane-bonded silica gel; Mobile phase: Phase A is acetonitrile, and Phase B is a 0.2% aqueous solution of phosphoric acid; Gradient elution: 0-15 min, 15% phase A; 15-20 min, 15%-18% phase A; 20-25 min, 18%-20% phase A; 25-35 min, 20%-25% phase A; 35-45 min, 25%-30% phase A; Parameters: Detection wavelength is 278 nm, column temperature is 28-30℃, flow rate is 0.8-1 mL / min, and injection volume is 10 μL.

[0010] The fingerprint spectrum of Scutellaria baicalensis stems and leaves provided by this invention can be used for the analysis of Scutellaria baicalensis stems and leaves.

[0011] Specifically, the present invention also provides a method for analyzing the stems and leaves of Astragalus membranaceus, comprising the following steps: The stems and leaves of Scutellaria baicalensis to be tested were extracted by ethanol reflux, and then concentrated after adding weight with methanol. The solution was dissolved in methanol and filtered to obtain the test solution. The fingerprint spectrum of the stems and leaves of Scutellaria baicalensis to be tested was obtained by chromatographic detection. The fingerprint spectrum of the stems and leaves of Scutellaria baicalensis to be tested was compared with the standard fingerprint spectrum of Scutellaria baicalensis stems and leaves to achieve the analysis of the stems and leaves of Scutellaria baicalensis.

[0012] Preferably, the mass-to-volume ratio of the Scutellaria baicalensis stems and leaves to be tested to the ethanol is 1g:20-25mL.

[0013] Preferably, concentration is carried out under water bath conditions of 60-90°C.

[0014] Preferably, the collected Scutellaria baicalensis stems and leaves can be judged to meet the quality requirements when the comparison results meet at least two of the following requirements: 1) The similarity between the fingerprint spectrum of the stem and leaf of Scutellaria baicalensis to be tested and the standard fingerprint spectrum is calculated, and the similarity is 0.9~1; 2) The area of ​​non-common peaks in the fingerprint spectrum of the stems and leaves of Scutellaria baicalensis to be tested does not exceed 10% of the total peak area; 3) The relative retention times of the common peaks other than the reference peak and the reference peak shall not deviate by more than ±10% from the standard fingerprint chromatogram.

[0015] The Scutellaria baicalensis stems and leaves to be tested include Scutellaria baicalensis stems and leaves medicinal materials or their extracts.

[0016] This invention enables efficient separation of multiple components, completing the detection of four target components (isosine baicalin 9.7 min → baicalin 33.3 min) within 35 minutes, with a resolution of >1.5, completely overcoming the defect of overlapping peaks under methanol mobile phase.

[0017] In the method of this invention, the linear correlation coefficient R² of the four components all reached 0.9999, covering a wide concentration range (e.g., isoxafotaside 20.94-670 μg / mL). The limit of detection was improved: by setting the integration threshold to 10% of the reference peak area, trace components could be captured (e.g., the lowest detectable concentration of taxanein is 16.34 μg / mL).

[0018] The present invention has the following beneficial technical effects: Methodological advantages: good precision, stability and repeatability: After systematic methodological validation, the RSD of the peak area of ​​the four index components (baicalin, baicalin, piperidin and isoxafen) is all <2%, the RSD of stability within 24 h is <2.1%, the recovery rate is 94.3%-105.1%, and the RSD is <4.5%.

[0019] Excellent separation and sensitivity: It can effectively separate four flavonoid components within 35 minutes, with symmetrical peaks, stable baseline, and low detection limit, making it suitable for conventional HPLC instruments.

[0020] Comprehensive Quality Control: Overcoming the Limitations of "Single Indicator" Approaches: Traditional methods using only baicalin or total flavonoids as indicators cannot comprehensively reflect the quality of Scutellaria baicalensis stems and leaves. This invention simultaneously identifies four active flavonoids, covering the main effective components of Scutellaria baicalensis stems and leaves, resulting in a more comprehensive evaluation. Establishing Standard Fingerprint Spectra: This invention specifies similarity ≥0.90, non-common peak area ≤10%, and relative retention time deviation ≤±10%, providing a unified and quantifiable quality assessment standard for Scutellaria baicalensis stems, leaves, and extracts.

[0021] Resource Utilization and Economic Benefits: Turning Waste into Treasure: Transforming the stems and leaves of Scutellaria baicalensis, which are not included in the Chinese Pharmacopoeia, into a monitorable and usable medicinal resource, improving the utilization rate of the whole plant and reducing resource waste. Supporting Industrialization: The method is simple, the reagents are inexpensive, and the equipment is widely available, making it easy to promote on the production line. It can provide standardized raw materials for marketed products such as "Scutellaria baicalensis Stem and Leaf Detoxification Capsules" and subsequent preparations.

[0022] Safety and Efficacy Assurance: Simultaneous monitoring of multiple components ensures the stability of active ingredient content across different batches of medicinal materials, thereby guaranteeing the consistency and safety of the formulation's efficacy. This provides a reliable chemical basis and quality traceability system for future pharmacodynamic and toxicological studies of Scutellaria baicalensis stems and leaves, including their anti-inflammatory, antibacterial, and antioxidant effects. Attached Figure Description

[0023] Figure 1 The chromatograms of each standard within 60 minutes are shown in the following order: baicalin standard, piperidin standard, baicalin standard, and isoxafen standard.

[0024] Figure 2 It is a standard fingerprint spectrum of Scutellaria baicalensis stems and leaves.

[0025] Figure 3 This is a comparison chart of each standard and the test sample.

[0026] Figure 4 These are HPLC chromatograms of Scutellaria baicalensis stem and leaf samples under different mobile phase conditions.

[0027] Figure 5 This is an HPLC chromatogram of baicalin standard.

[0028] Figure 6 This is an HPLC chromatogram of the piperidine standard.

[0029] Figure 7 This is an HPLC chromatogram of baicalin standard.

[0030] Figure 8 This is the HPLC chromatogram of isosorbide disulfide standard.

[0031] Figure 9 This is an HPLC chromatogram of a mixed standard of baicalin, piperidin, baicalin, and isoxafen, as well as a sample of Scutellaria baicalensis stems and leaves.

[0032] Figure 10 It is a linear regression curve of the standards for baicalin, piperidine, baicalin and isoxafen. Detailed Implementation

[0033] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0034] Through pretreatment of Scutellaria baicalensis stem and leaf samples, exploration and optimization of chromatographic conditions, and preliminary laboratory analysis of the complete components of Scutellaria baicalensis stem and leaf UHPLC-MS, the pharmacologically active components with high proportions in Scutellaria baicalensis stem and leaf, namely baicalin, piperidin, baicalin, and isoxafen, were selected as the components to be detected in HPLC. A Waters X select HSS T3 5μm column was used; the mobile phase was acetonitrile (A) and 0.2% phosphoric acid aqueous solution (B); the elution ratios were: 0-15 min, 15% A; 15-20 min, 15% A-18% A; 20-25 min, 18% A-20% A; 25-35 min, 20% A-25% A; 35-45 min, 25% A-30% A; the detection wavelength was 278 nm; the column temperature was 30 ℃; the flow rate was 1 mL / min; and the injection volume was 10 μL. The average recoveries of the components from the stems and leaves of Scutellaria baicalensis ranged from 94.29588423% to 105.0793268%, with RSDs ranging from 3.028399053% to 4.426626213%. The linear correlation coefficients of all components reached 0.9999, indicating that the method was rapid, reliable, and stable.

[0035] Example 1 I. Chromatographic Detection Baicalin, Taxodiacin, Baicalin, and Isoxastatin (China National Institutes for Food and Drug Control).

[0036] Instrument: Agilent 1290 Infinity II high performance liquid chromatograph.

[0037] Chromatographic conditions: An octadecylsilane-bonded silica gel column was used as the packing material.

[0038] The chromatographic column used was a Waters X select HSS T3 5μm column. Mobile phase A was acetonitrile, and mobile phase B was 0.2% phosphoric acid aqueous solution.

[0039] The elution gradient is as follows: 0-15 min, 15% A; 15-20 min, 15% A-18% A; 20-25 min, 18% A-20% A; 25 min-35 min, 20% A-25% A; 35-45 min, 25% A-30% A.

[0040] The detection wavelength was 278 nm, the column temperature was 30 ℃, the flow rate was 1.0 mL / min, and the injection volume was 10 μL.

[0041] 1) Selection of mobile phase: The main components of this drug are various flavonoids. It is necessary to use a gradient separation method to achieve good separation of the main components within the shortest possible elution time. Acetonitrile was used as the mobile phase to reduce baseline drift during gradient elution. Considering that adding an appropriate amount of salt to the mobile phase can improve the separation effect, 0.2% phosphate solution was investigated as the mobile phase. The results showed that 0.2% phosphate solution provided better peak resolution, and therefore, it was selected as the appropriate mobile phase. See the chromatogram below. Figure 1 .

[0042] 2) Wavelength selection: Full wavelength detection was performed, and it was found that the peaks and separation of all components were good at 278nm. Therefore, the detection wavelength was determined to be 278nm.

[0043] The liquid chromatogram of Scutellaria baicalensis stems and leaves at 278 nm is shown below. Figure 2 .

[0044] 3) Setting the gradient time Considering the complex composition of Scutellaria baicalensis stems and leaves, and the significant differences in polarity among different components, after repeated adjustments to the elution conditions, it was found that setting the initial acetonitrile concentration to 15% resulted in good separation of baicalin and taxine. Gradient elution from 0 to 40 minutes was used to ensure the most effective separation of this chromatographic peak. Under these conditions, most peaks achieved good separation with moderate retention times, and no other peaks appeared after 40 minutes. See details below. Figure 2 .

[0045] 4) Instrument and integration parameters Instrument parameters: Agilent 1290 Infinity II high-performance liquid chromatograph, Chemstation chromatography workstation. Column temperature 30℃, flow rate 1.0 ml / min. Integration parameters: minimum peak area is 10% of the peak area of ​​the reference (S), and minimum peak height is 10% of the peak height of S. This setting avoids the calculation of some very small chromatographic peaks (single peak area less than 1% of the total peak area) while ensuring correlation with the reference.

[0046] II. Construction of fingerprint map.

[0047] 1. Preparation of the test solution Preparation of the test solution: Take 1g of Scutellaria baicalensis stems and leaves, add 25 times the amount of 60% ethanol for reflux extraction, take the supernatant, filter it through a 0.22μm microporous membrane, and take the filtrate as the test solution.

[0048] Preparation of standard solution: Appropriate amounts of baicalin, scutellarin, piperidin, and isoxafen were added to methanol to prepare a solution containing 0.1 mg per mL, which served as the standard solution. The HPLC chromatogram of the obtained standard solution is shown below. Figure 1 .

[0049] Standard fingerprint chromatograms were developed based on 10 batches of samples. The fingerprint chromatograms of the 10 batches of test samples (2-year-old Scutellaria baicalensis stems and leaves from Puwa Township, Fangshan District, Beijing) were compared with the standard fingerprint chromatograms. The similarity was between 0.90 and 1.00. The standard fingerprint chromatogram for Scutellaria baicalensis stems and leaves is shown below. Figure 2 .

[0050] Comparison of the calibrated standard and the sample is shown in the figure. Figure 3 The left figure is the HPLC chromatogram of the calibrated mixed standard, and the right figure is the HPLC chromatogram of the sample. The components labeled 1, 2, 3, and 4 in the figure are baicalin, piperidine, baicalin, and isoxafen, respectively. It can be seen that the sample also showed a peak at the same time, indicating that the sample contains baicalin, piperidine, baicalin, and isoxafen.

[0051] Example 2: Exploration of liquid chromatography conditions and methodological validation 1. Establishment of chromatographic conditions This example compares the separation of compounds in samples using methanol as phase A / 0.2% phosphoric acid as phase B and acetonitrile as phase A / 0.2% phosphoric acid as phase B. Figure 4 It can be seen that when the mobile phase is acetonitrile as phase A and 0.2% phosphoric acid as phase B, baicalin and taxine tend to gradually separate. However, when methanol and phosphoric acid water are chosen as the mobile phase, no components are effectively eluted. Therefore, acetonitrile as phase A and 0.2% phosphoric acid as phase B are selected for subsequent experiments.

[0052] 2. Comparison of chromatograms of standards and samples In this embodiment, acetonitrile was used as phase A and 0.2% phosphoric acid was used as phase B for isoconcentration elution. After isoconcentration elution, piperidin and baicalin were separated. Gradient elution was then set up, and the optimal elution conditions for the sample were finally determined (0-15 min, 15% A; 15-20 min, 15% A-18% A; 20-25 min, 18% A-20% A; 25 min-35 min, 20% A-25% A; 35-45 min, 25% A-30% A). Figures 5 to 9 This study compares the elution of Scutellaria baicalensis stem and leaf samples, single standards, and mixed standards under these conditions. Figures 5 to 8It can be observed that under these elution conditions, the peak elution time of baicalin was 18.628 min, that of piperidin was 16.192 min, that of baicalin was 33.314 min, and that of isoxafen was 9.743 min.

[0053] 3. Validation of analytical method results 1) Linear correlation results like Figure 10 As shown in Figure A, the horizontal axis (X) represents the concentration of isosulfanilamide standard, and the vertical axis (Y) represents the peak area. A standard curve was plotted, and the corresponding regression equation was calculated. The resulting regression equation is: Y =11.885 X +7.7686(R 2 =0.9999, linear range 20.94-670 μg / mL), indicating good linearity. Figure 10 Plot B shows a standard curve with the concentration of the piracetamine standard (X) on the x-axis and the peak area on the y-axis (Y). The corresponding regression equation was then calculated. The regression equation is Y = 31.201X + 12.029 (R²). 2 =0.9999, linear range 16.34-524 μg / mL), indicating good linearity. Figure 10 In Figure C, a standard curve is plotted with the concentration of baicalin standard (X) on the x-axis and the peak area (Y) on the y-axis. The corresponding regression equation is then calculated. The regression equation is as follows: Y =24.238 X -32.578 (R) 2 =0.9999, linear range 14.81-474 μg / mL), good linearity. Figure 10 In Figure C, a standard curve is plotted with the concentration of baicalin standard (X) on the x-axis and the peak area (Y) on the y-axis. The corresponding regression equation is then calculated. The regression equation is as follows: Y =35.531 X -13.347 (R) 2 =0.9999, linear range 17.06-546 μg / mL), good linearity.

[0054] 2) Precision test results The RSD of the peak areas of the four components—baicalin, piperidin, baicalin, and isoxafen—was calculated. The precision of each component ranged from 0.415085785% to 1.125299825%, demonstrating the good precision of the method of this invention. Specific results are shown in Table 1.

[0055] Table 1 Precision Results

[0056] 3) Results of repeatability testing The peak areas and RSDs of four components—baicalin, piperidin, baicalin, and isoxafen—were calculated. The RSDs of each component ranged from 1.041247295% to 1.60891556%, indicating that the established method had good reproducibility.

[0057] Table 2 Repeatability Test Results

[0058] 4) Stability test results The RSD of the peak areas of four components—baicalin, piperidin, baicalin and isoxafen—were calculated after the sample was placed at room temperature for 0-24 h. The RSD of the peak areas of each component ranged from 0.596055691% to 2.039117348%, indicating that the extract was relatively stable at room temperature for 24 h.

[0059] Table 3 Stability test results

[0060] 5) Spiking recovery test and results The recovery rates of each detected component were calculated, as shown in Table 4. The average recovery rates remained between 94.29588423% and 105.0793268%, and the RSDs were between 3.028399053% and 4.426626213%. The recovery rate of the method of the present invention is good.

[0061] Table 4 Results of the spiking recovery test

[0062] The HPLC method established in this invention can rapidly separate four flavonoid components from the stem and leaf extract of Scutellaria baicalensis within 35 min: isoxafen, baicalin, piperidin, and baicalin, in that order. The peak times are 9.743 min, 18.628 min, 16.192 min, and 33.314 min, respectively. HPLC method validation showed that the average recoveries of Scutellaria baicalensis stem and leaf extracts ranged from 94.29588423% to 105.0793268%, with RSDs ranging from 3.028399053% to 4.426626213%. Stability tests revealed that the RSDs of the peak areas for each component ranged from 0.596055691% to 2.039117348%, indicating that the extract is relatively stable within 24 h at room temperature. Linear correlation studies of the components validated that the method is stable, rapid, operable, and accurate. The linear correlation coefficients for all target components were as high as 0.9999, demonstrating an ideal linear relationship. This invention's method can determine the content of target components in Scutellaria baicalensis stems and leaves, providing a research foundation for the qualitative and quantitative analysis of Scutellaria baicalensis stems and leaves, their extracts, and related preparations.

Claims

1. A method for constructing a fingerprint spectrum of Scutellaria baicalensis stems and leaves, comprising the following steps: S1. Preparation of standard solutions: Weigh the standards of baicalin, scutellarin, piperidin, and isoxafen, and dilute with methanol to 5-474 μg / mL, 18-546 μg / mL, 17-524 μg / mL, and 22-670 μg / mL, respectively; perform liquid chromatography to obtain the standard comparison peaks; S2. Sample solution preparation: Weigh the powder of Scutellaria baicalensis stems and leaves, extract with ethanol by reflux, and then make up to volume with methanol; perform liquid chromatography to obtain the standard fingerprint spectrum; S3. Standard fingerprint chromatogram development: Based on the retention time of the chromatographic peak of the standard comparison peak, calculate the relative retention time of other common chromatographic peaks in the standard fingerprint chromatogram, with a relative standard deviation not exceeding ±20%. In steps S1 and S2, the liquid chromatography detection conditions are as follows: Column: Waters Xselect HSS T3 5μm, packed with octadecylsilane-bonded silica gel; Mobile phases: Phase A is acetonitrile, and Phase B is a 0.2% aqueous phosphoric acid solution. Gradient elution: 0-15 min, 15% phase A; 15-20 min, 15%-18% phase A; 20-25 min, 18%-20% phase A; 25-35 min, 20%-25% phase A; 35-45 min, 25%-30% phase A; Parameters: Detection wavelength is 278 nm, column temperature is 28-30℃, flow rate is 0.8-1 mL / min, and injection volume is 10 μL.

2. The application of the construction method described in claim 1 in the analysis of Scutellaria baicalensis stems and leaves.

3. A method for analyzing the stems and leaves of Astragalus membranaceus, comprising the following steps: The stems and leaves of Scutellaria baicalensis to be tested were extracted by ethanol reflux, concentrated after adding weight with methanol, dissolved in methanol and filtered to obtain the test solution, and the fingerprint spectrum of the stems and leaves of Scutellaria baicalensis to be tested was obtained by chromatographic detection. The fingerprint spectrum of the stems and leaves of Scutellaria baicalensis to be tested was compared with the standard fingerprint spectrum of Scutellaria baicalensis stems and leaves constructed by the method described in claim 1, thus realizing the analysis of the stems and leaves of Scutellaria baicalensis. The chromatographic detection conditions are as follows: Column: Waters Xselect HSS T3 5μm, packed with octadecylsilane-bonded silica gel; Mobile phases: Phase A is acetonitrile, and Phase B is a 0.2% aqueous solution of phosphoric acid. Gradient elution: 0-15 min, 15% phase A; 15-20 min, 15%-18% phase A; 20-25 min, 18%-20% phase A; 25-35 min, 20%-25% phase A; 35-45 min, 25%-30% phase A; Parameters: Detection wavelength is 278 nm, column temperature is 28-30℃, flow rate is 0.8-1 mL / min, and injection volume is 10 μL.

4. The method according to claim 3, characterized in that: The mass-to-volume ratio of the Scutellaria baicalensis stems and leaves to be tested to the ethanol is 1g:20-25mL.

5. The method according to claim 3 or 4, characterized in that: Concentration is carried out under water bath conditions of 60-90℃.

6. The method according to claim 3 or 4, characterized in that: If the comparison results meet at least two of the following requirements, the collected Scutellaria baicalensis stems and leaves can be judged to meet the quality requirements: 1) The similarity between the fingerprint spectrum of the stem and leaf of Scutellaria baicalensis to be tested and the standard fingerprint spectrum is calculated, and the similarity is 0.9~1; 2) The area of ​​non-common peaks in the fingerprint spectrum of the stems and leaves of Scutellaria baicalensis to be tested does not exceed 10% of the total peak area; 3) The relative retention times of the common peaks other than the reference peak and the reference peak shall not deviate by more than ±10% from the standard fingerprint chromatogram.

7. The method according to claim 3 or 4, characterized in that: The Scutellaria baicalensis stems and leaves to be tested include Scutellaria baicalensis stems and leaves medicinal materials or their extracts.

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