A method for extracting Rhododendron amurense and application of its extract

Abstract

The present invention discloses a method for extracting R. mandshurica and the use of its extract, belonging to the field of traditional Chinese medicine preparation. The method sequentially comprises the following steps: S0, supercritical CO₂ extraction of R. mandshurica; S11, alkali extraction: extracting the R. mandshurica residue obtained in S0 with an alkaline ethanol aqueous solution, filtering to obtain an alkaline extract and an alkaline-extracted R. mandshurica residue; S12, acid extraction: extracting the R. mandshurica residue obtained in S11 with an acidic ethanol aqueous solution, filtering to obtain an acidic extract and an acid-extracted R. mandshurica residue; S2, activated carbon adsorption: subjecting the liquid obtained in S1 through alkaline and acid extraction to activated carbon adsorption to obtain a functional component mixture. The present invention reduces or prevents the entry of ashwood toxins into the final product.

Description

Technical Field

[0001] The present invention relates to the field of traditional Chinese medicine preparation, and in particular to a method for extracting Rhododendron amurense and application of the extract. Background Art

[0002] CN115177592A also discloses a preparation method and product of cough and asthma granules. In the preparation method, the extraction solvent of Rhodiola rosea is an aqueous solution with a volume fraction of 40% ethanol, and the extraction temperature is 30~50℃ (compared with the pharmacopoeia, the upper limit temperature is increased by 10℃).

[0003] Although the cough and asthma granules disclosed in CN115177592A have good therapeutic effects, they have certain side effects. For example, the ashwood toxin from the leaves and flowers of the rhododendron plant is brought into the finished granules. The ashwood toxin affects the nervous system by interfering with sodium ion channels, which can cause vomiting, diarrhea, arrhythmia and even shock.

[0004] The above background technology is for facilitating understanding of the present invention and is not a known technology disclosed to the general public before the application of the present invention. Summary of the Invention

[0005] In view of the above-mentioned defects, the present invention provides a method for extracting Rhododendron chinense, which aims to improve at least one of the problems mentioned in the background technology.

[0006] The technical solution is: a method for extracting Rhododendron chinense, which comprises the following steps in sequence:

[0007] S0, supercritical CO2 extraction of R. mandshurica, pressure of 20 MPa ~ 30 MPa, entrainer of 3% v / v ~ 6% v / v ethanol, temperature of 40 ° C ~ 50 ° C, extraction time of 25 min ~ 35 min, to obtain a mixture of R. mandshurica residue and ethanol;

[0008] S1, alkali extraction and acid extraction:

[0009] S11, alkali extraction: extracting the R. marianum residue obtained in S0 in an alkaline ethanol aqueous solution, filtering to obtain an alkaline extract and the R. marianum residue after alkali extraction;

[0010] S12, acid extraction: extracting the R. fulva residue obtained in S11 in an acidic ethanol aqueous solution, filtering to obtain an acidic lower extract and the R. fulva residue after acid extraction;

[0011] S2, activated carbon adsorption: The liquid obtained by alkali extraction and acid extraction of S1 is adsorbed on activated carbon to obtain a functional component mixed liquid.

[0012] Further, in S11, the residue of Rhododendron chinense after alkali extraction is squeezed to obtain alkali-extracted pressed liquid and Rhododendron chinense residue after alkali extraction and pressing, and the alkaline lower extract and the alkali-extracted pressed liquid are combined to form an alkali-extracted combined liquid; in S12, the residue of Rhododendron chinense after acid extraction is squeezed to obtain acid-extracted pressed liquid and Rhododendron chinense residue after acid extraction and pressing, and the acid lower extract and the acid-extracted pressed liquid are combined to form an acid-extracted combined liquid.

[0013] Furthermore, in S11, the alkaline ethanol aqueous solution includes an ethanol aqueous solution and a NaOH aqueous solution, the alkaline ethanol aqueous solution is a 30% v / v~50% v / v ethanol aqueous solution, the NaOH aqueous solution is a 0.05wt%~0.15wt% NaOH aqueous solution, the pH is 8~9, the extraction time is 70 h~90 h, and the temperature is 30°C~40°C; the extraction is carried out under stirring, the stirring frequency is once every 7~9 hours, and each stirring time is 8~12 minutes.

[0014] Furthermore, in S11, the amount of the ethanol aqueous solution is 4500 ml to 5500 ml of the ethanol aqueous solution per 1000 g of Rhododendron chinense.

[0015] Furthermore, in S12, the acidic ethanol aqueous solution includes an ethanol aqueous solution and a citric acid aqueous solution, the acidic ethanol aqueous solution is a 30% v / v~50% v / v ethanol aqueous solution, the citric acid aqueous solution is a 0.2wt%~0.8wt% citric acid aqueous solution, the pH is 3.5~4.5, the extraction time is 70 h~90 h, the temperature is 30℃~40℃, the stirring number is once every 7~9 hours, and each stirring time is 8~12 minutes.

[0016] Furthermore, in S12, the amount of the ethanol aqueous solution is 4500 ml to 5500 ml of the ethanol aqueous solution per 1000 g of Rhododendron chinense.

[0017] Furthermore, S2 includes the following steps:

[0018] S21, taking the alkali extraction combined liquid, adjusting the pH to 7 with a 0.2 wt% to 0.8 wt% aqueous solution of citric acid, then adding activated carbon to the alkali extraction combined liquid in an amount of 0.5 wt% to 1.5 wt% of the alkali extraction combined liquid, and filtering to obtain an alkali extraction filtrate;

[0019] S22, taking the acid extraction combined liquid, adding activated carbon to the acid extraction combined liquid, wherein the activated carbon added is 0.5 wt% to 1.5 wt% of the acid extraction combined liquid, filtering to remove the activated carbon, and obtaining an acid extraction filtrate;

[0020] S23, combining the alkali extraction filtrate and the acid extraction filtrate to form the functional component mixture.

[0021] Furthermore, in S0, the extraction object is the leaves or flowers of Rhododendron chinense

[0022] The present invention also provides an application of the extract in preparing Xiaokechuan granules.

[0023] The technical solution is: an extract is used in the preparation of Xiaokechuan granules, comprising the following steps:

[0024] Taking an extract, which is a mixture of the functional ingredients mentioned above;

[0025] The functional component mixed solution is spray-dried after recovering ethanol to obtain extract powder, and the extract powder is mixed with an appropriate amount of dextrin for adjustment, and granules are prepared, dried, granulated, sieved, mixed, and packaged into bags.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention studies the properties of ashwood toxins and total flavonoids and rhododendrons, which are effective ingredients for relieving cough and asthma. Based on the differences in the properties of ashwood toxins and total flavonoids and rhododendrons, the extraction process of Rhododendron amurense is improved. By sequentially combining supercritical CO2 extraction, alkaline extraction, acid extraction, and activated carbon adsorption, the entry of ashwood toxins into the final product is reduced or avoided. DETAILED DESCRIPTION

[0028] As used herein:

[0029] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0030] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed alone. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including the range "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0031] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] Those skilled in the art will appreciate that the following examples are intended to illustrate the present invention only and should not be construed as limiting the scope of the present invention. In the examples, where specific conditions are not specified, conventional conditions or manufacturer-recommended conditions were used. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0033] In these examples, parts and percentages are by mass unless otherwise indicated.

[0034] "Parts by mass" refers to the basic unit of measurement used to express the mass ratio of multiple components. One part can represent any unit of mass, such as 1g or 2.689g. If we say that the mass of component A is a parts and the mass of component B is b parts, this means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, we could say that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number representing a multiplication factor). It's important to note that, unlike parts by mass, the sum of the mass of all components is not limited to 100 parts.

[0035] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0036] Example 1

[0037] Take dried leaves of Rhododendron chinense, crush them, and pass them through a 40-mesh sieve to obtain Rhododendron chinense powder, which is used in Examples 2 to 4 and Comparative Examples 1 to 4.

[0038] Example 2 A method for extracting Rhododendron chinense, comprising the following steps:

[0039] S0, supercritical CO2 extraction:

[0040] 1000 g of the R. manshuriensis powder of Example 1 was weighed and subjected to supercritical CO2 extraction for 30 min at a temperature of about 45°C, a CO2 gas atmosphere, a pressure of 25 MPa, an entrainer of 5% v / v ethanol, to obtain a mixed solution of R. manshuriensis residue and ethanol.

[0041] S1, alkali extraction and acid extraction:

[0042] S11, Alkali Extraction:

[0043] Take S0 of the Rhizoma Cibotii residue, add 5000 ml of 40% v / v ethanol aqueous solution and 0.1 wt% NaOH aqueous solution, immerse in a closed manner and stir, the temperature is 35 ° C, the stirring frequency is once every 8 hours, each stirring is 10 minutes, the pH is controlled at about 8, and the extraction time is 84 hours; filter to obtain an alkaline lower extract and an Rhizoma Cibotii residue after alkali extraction, press the Rhizoma Cibotii residue after alkali extraction to obtain an alkali-extracted pressed liquid and an Rhizoma Cibotii residue after alkali extraction and pressing, and combine the alkaline lower extract and the alkali-extracted pressed liquid to form an alkali-extracted combined liquid.

[0044] S12, acid extraction:

[0045] Take the alkali-extracted and squeezed R. fulva residue of S11, add 5000 ml of 40% v / v ethanol aqueous solution and 0.5% citric acid aqueous solution, immerse in a sealed container and stir at a temperature of 35°C, stir once every 8 hours, each stirring for 10 minutes, control the pH at about 4, and extract for 84 hours; filter to obtain an acidic lower extract and an acid-extracted R. fulva residue, squeeze the acid-extracted R. fulva residue to obtain an acid-extracted squeezed liquid and an acid-extracted and squeezed R. fulva residue, and combine the acidic lower extract and the acid-extracted squeezed liquid to form an acid-extracted combined liquid.

[0046] S2, activated carbon adsorption

[0047] S21: Taking the combined alkali extraction solution, adjusting the pH to approximately 7 with a 0.5% aqueous citric acid solution, then adding activated carbon to the combined alkali extraction solution in an amount equal to 1 wt % of the combined alkali extraction solution, filtering, and removing the activated carbon to obtain an alkali extraction filtrate. The purpose of adjusting the pH of the combined alkali extraction solution to approximately 7 in this step is to avoid damaging the activated carbon.

[0048] S22, taking the acid extraction combined liquid, adding activated carbon to the acid extraction combined liquid, wherein the amount of activated carbon added is 1 wt % of the acid extraction combined liquid, filtering to remove the activated carbon, and obtaining an acid extraction filtrate.

[0049] S23, combining the alkali extraction filtrate and the acid extraction filtrate to form a functional component mixture.

[0050] In this embodiment, the ethanol mixture of S0 is mixed with the eluate obtained by eluting the activated carbon after adsorption of S2 to remove the ethanol and eluent, thereby obtaining a substance as a byproduct of the ashwood toxin. The byproduct of the ashwood toxin has traditionally been used to prepare pesticides, and is now used to prepare scientific research chemicals such as sodium channel modulators.

[0051] Example 3

[0052] The difference between this embodiment and embodiment 2 is that in S0, the temperature is about 40°C.

[0053] Example 4

[0054] The difference between this embodiment and embodiment 2 is that in S0, the temperature is about 50°C.

[0055] Comparative Example 1

[0056] A method for extracting Rhodiola rosea comprises the following steps:

[0057] S0, supercritical CO2 extraction:

[0058] 1000 g of the R. manshuriensis powder of Example 1 was weighed and subjected to supercritical CO2 extraction for 30 min at a temperature of about 45°C, a CO2 gas atmosphere, a pressure of 25 MPa, an entrainer of 5% v / v ethanol, to obtain a mixed solution of R. manshuriensis residue and ethanol.

[0059] S1, alkali extraction and acid extraction:

[0060] S11, Alkali Extraction:

[0061] Take S0 of the Rhizoma Cibotii residue, add 5000 ml of 40% v / v ethanol aqueous solution and 0.1 wt% NaOH aqueous solution, immerse in a closed manner and stir, the temperature is 35 ° C, the stirring frequency is once every 8 hours, each stirring is 10 minutes, the pH is controlled at about 8, and the extraction time is 84 hours; filter to obtain an alkaline lower extract and an Rhizoma Cibotii residue after alkali extraction, press the Rhizoma Cibotii residue after alkali extraction to obtain an alkali-extracted pressed liquid and an Rhizoma Cibotii residue after alkali extraction and pressing, and combine the alkaline lower extract and the alkali-extracted pressed liquid to form an alkali-extracted combined liquid.

[0062] S12, acid extraction:

[0063] Take the alkali-extracted and squeezed R. fulva residue of S11, add 5000 ml of 40% v / v ethanol aqueous solution and 0.5% citric acid aqueous solution, immerse in a sealed container and stir at a temperature of 35°C, stir once every 8 hours, each stirring for 10 minutes, control the pH at about 4, and extract for 84 hours; filter to obtain an acidic lower extract and an acid-extracted R. fulva residue, squeeze the acid-extracted R. fulva residue to obtain an acid-extracted squeezed liquid and an acid-extracted and squeezed R. fulva residue, and combine the acidic lower extract and the acid-extracted squeezed liquid to form an acid-extracted combined liquid.

[0064] S2, adjusting the pH of the alkali extraction combined solution to about 7 with a 0.5% citric acid aqueous solution, and mixing the alkali extraction combined solution with the acid extraction combined solution to form a functional component mixed solution.

[0065] In this comparative example, the substance after removing ethanol from the ethanol mixture of S0 is used as the by-product of the ashwood toxin.

[0066] Comparative Example 2

[0067] A method for extracting Rhodiola rosea comprises the following steps:

[0068] S0, supercritical CO2 extraction:

[0069] 1000 g of the R. manshuriensis powder of Example 1 was weighed and subjected to supercritical CO2 extraction for 30 min at a temperature of about 45°C, a CO2 gas atmosphere, a pressure of 25 MPa, an entrainer of 5% v / v ethanol, to obtain a mixed solution of R. manshuriensis residue and ethanol.

[0070] S1, take the R. mandshurica residue of S0, add 5000 ml of 40% v / v ethanol aqueous solution, immerse and stir in a sealed solution at 35°C, stir once every 8 hours, stir for 10 minutes each time, and extract for 168 hours; filter to obtain an extract and R. mandshurica residue after extraction, squeeze the R. mandshurica residue after extraction to obtain a squeezed liquid and a squeezed R. mandshurica residue, and combine the extract and the squeezed liquid to form a combined liquid.

[0071] S2, adding activated carbon to the combined liquid of S1, wherein the amount of activated carbon added is 1wt% of the combined liquid, filtering and removing the activated carbon to obtain a functional component mixed liquid.

[0072] In this comparative example, the ethanol mixture of S0 is mixed with the eluent obtained by eluting the activated carbon after adsorption of S2 to remove the ethanol and the eluent, and the substance after the removal of the ethanol and the eluent is used as the byproduct of the ashwood toxin.

[0073] Comparative Example 3

[0074] A method for extracting Rhodiola rosea comprises the following steps:

[0075] S0, supercritical CO2 extraction:

[0076] 1000 g of the R. manshuriensis powder of Example 1 was weighed and subjected to supercritical CO2 extraction for 30 min at a temperature of about 45°C, a CO2 gas atmosphere, a pressure of 25 MPa, an entrainer of 5% v / v ethanol, to obtain a mixed solution of R. manshuriensis residue and ethanol.

[0077] S1, acid extraction and alkaline extraction:

[0078] S11, acid extraction:

[0079] Take S0 of the R. mandshurica residue, add 5000 ml of 40% v / v ethanol aqueous solution and 0.5% citric acid aqueous solution, immerse in a sealed container and stir at a temperature of 35°C, stir once every 8 hours, stir for 10 minutes each time, control the pH at around 8, and extract for 84 hours; filter to obtain an acidic lower extract and an acid-extracted R. mandshurica residue, press the acid-extracted R. mandshurica residue to obtain an acid-extracted pressed liquid and an acid-extracted pressed R. mandshurica residue, and combine the acidic lower extract and the acid-extracted pressed liquid to form an acid-extracted combined liquid.

[0080] S12, Alkali Extraction:

[0081] Take the acid-extracted and squeezed Rhizoma Coptidis residue of S11, add 5000 ml of 40% v / v ethanol aqueous solution and 0.1 wt% NaOH aqueous solution, immerse in a closed manner and stir at a temperature of 35°C, stir once every 8 hours, stir for 10 minutes each time, control the pH at about 4, and extract for 84 hours; filter to obtain an alkaline extract and an alkali-extracted Rhizoma Coptidis residue, squeeze the alkali-extracted Rhizoma Coptidis residue to obtain an alkali-extracted squeezed liquid and an alkali-extracted Rhizoma Coptidis residue, and combine the alkaline extract and the alkali-extracted squeezed liquid to form an alkali-extracted combined liquid.

[0082] S2, activated carbon adsorption

[0083] S21: Taking the combined alkali extraction solution, adjusting the pH to approximately 7 with a 0.5% aqueous citric acid solution, then adding activated carbon to the combined alkali extraction solution in an amount equal to 1 wt % of the combined alkali extraction solution, filtering, and removing the activated carbon to obtain an alkali extraction filtrate. The purpose of adjusting the pH of the combined solution 1 to approximately 7 in this step is to avoid damaging the activated carbon.

[0084] S22, taking the acid extraction combined liquid, adding activated carbon to the acid extraction combined liquid, wherein the amount of activated carbon added is 1 wt % of the acid extraction combined liquid, filtering to remove the activated carbon, and obtaining an acid extraction filtrate.

[0085] S23, combining the alkali extraction filtrate and the acid extraction filtrate to form a functional component mixture.

[0086] In this embodiment, the ethanol mixture of S0 is mixed with the eluent obtained by eluting the activated carbon after adsorption of S2 to remove the ethanol and the eluent, and the substance obtained by removing the ethanol and the eluent is used as the byproduct of the ashwood toxin.

[0087] Comparative Example 4 (using the extraction method of CN115177592A)

[0088] S1. Take 1000 g of the R. mandshurica powder of Example 1, add 5000 ml of 40% v / v ethanol aqueous solution, immerse and stir in a sealed solution at 35° C., stir once every 8 hours for 10 minutes each time, and extract for 168 hours; filter to obtain an extract and R. mandshurica residue, squeeze the R. mandshurica residue to obtain a squeezed liquid and the squeezed R. mandshurica residue, combine the extract and the squeezed liquid to form a combined liquid, which is a functional component mixture.

[0089] The functional component mixtures of Examples 2 to 4 and Comparative Examples 1 to 4 were subjected to the following operations:

[0090] After recovering the ethanol, spray drying is performed to obtain extract powder, and the extract powder is mixed with dextrin to adjust the volume to 1000 g (wherein the amount of dextrin added is adjusted according to the amount of extract powder), granules are prepared, dried, granulated, sieved, mixed, and packaged into bags, with each bag of Xiaokechuan granules containing 2 g.

[0091] The prepared Xiaokechuan granules were tested for total flavonoids, rhododendron and quercetin, and the results are shown in Table 1.

[0092] Table 1 Test results

[0093] In Table 1, each test result is the average value of 10 samples, and each sample is a bag of Xiaokechuan granules (i.e., weighing 2g).

[0094] As can be seen from Table 1, supercritical CO2 extraction and activated carbon adsorption are extremely effective in reducing the ashwood toxin in the Chinese medicine preparation of Manshanhong. No ashwood toxin was detected in Examples 2-4 and Comparative Examples 2 and 3. Although ashwood toxin was detected in Comparative Example 1, the content was very small, far below the requirement of 0.01 ug / g for the latest version (2020 edition of the Pharmacopoeia of the People's Republic of China) for marketed preparations. However, from the comparison of Comparative Example 2 with Comparative Example 4, it can be seen that supercritical CO2 extraction and activated carbon adsorption are not conducive to the extraction of the cough and asthma functional component, and the content of the cough and asthma functional component is reduced. Compared with Comparative Examples 2 and 3, under the same conditions, only by first extracting the functional component that is easy to extract under alkaline conditions and then extracting the functional component under acidic conditions, the final cough and asthma functional component is further improved compared to the existing one. However, by first extracting the functional component that is easy to extract under acidic conditions and then extracting the functional component under alkaline conditions, the final cough and asthma functional component is not improved compared to the existing one.

[0095] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0096] In addition, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is intended to be within the scope of the present application and form different embodiments. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of this application and should not be regarded as an admission or any form of implication that the information constitutes prior art already known to those skilled in the art.

Claims

1. A method for extracting Rhododendron chinense, characterized in that: The following steps are involved: S0, supercritical CO2 extraction of R. mandshurica, pressure of 20 MPa ~ 30 MPa, entrainer of 3% v / v ~ 6% v / v ethanol, temperature of 40 ° C ~ 50 ° C, extraction time of 25 min ~ 35 min, to obtain a mixture of R. mandshurica residue and ethanol; S1, alkali extraction and acid extraction: S11, alkali extraction: extracting the R. marianum residue obtained in S0 in an alkaline ethanol aqueous solution, filtering to obtain an alkaline extract and the R. marianum residue after alkali extraction; S12, acid extraction: extracting the R. fulva residue obtained in S11 in an acidic ethanol aqueous solution, filtering to obtain an acidic lower extract and the R. fulva residue after acid extraction; S2, activated carbon adsorption: The liquid obtained by alkali extraction and acid extraction of S1 is adsorbed on activated carbon to obtain a functional component mixed liquid; In S11, the alkali-extracted Rhizoma Caryophylli residue is squeezed to obtain an alkali-extracted pressed liquid and an Rhizoma Caryophylli residue after alkali extraction and pressing, and the alkaline lower extract and the alkali-extracted pressed liquid are combined to form an alkali-extracted combined liquid; in S12, the acid-extracted Rhizoma Caryophylli residue is squeezed to obtain an acid-extracted pressed liquid and an acid-extracted pressed Rhizoma Caryophylli residue, and the acid lower extract and the acid-extracted pressed liquid are combined to form an acid-extracted combined liquid; In S11, the alkaline ethanol aqueous solution is an ethanol aqueous solution and a NaOH aqueous solution, the alkaline ethanol aqueous solution is a 30% v / v~50% v / v ethanol aqueous solution, the NaOH aqueous solution is a 0.05wt%~0.15wt% NaOH aqueous solution, the pH is 8~9, the extraction time is 70 h~90 h, and the temperature is 30°C~40°C; the extraction is carried out under stirring, the stirring frequency is once every 7~9 h, and each stirring time is 8~12 min; In S12, the acidic ethanol aqueous solution is an ethanol aqueous solution and a citric acid aqueous solution, the acidic ethanol aqueous solution is a 30% v / v~50% v / v ethanol aqueous solution, the citric acid aqueous solution is a 0.2wt%~0.8 wt% citric acid aqueous solution, the pH is 3.5~4.5, the extraction time is 70 h~90 h, the temperature is 30℃~40℃, the stirring number is once every 7~9 hours, and each stirring time is 8~12 minutes.

2. The method for extracting Rhododendron chinense according to claim 1, wherein In S11, the amount of the ethanol aqueous solution is 4500 ml to 5500 ml of the ethanol aqueous solution per 1000 g of Rhododendron chinense.

3. The method for extracting Rhododendron chinense according to claim 1, wherein S2 includes the following steps: S21, taking the alkali extraction combined liquid, adjusting the pH to 7 with a 0.2 wt% to 0.8 wt% aqueous solution of citric acid, then adding activated carbon to the alkali extraction combined liquid in an amount of 0.5 wt% to 1.5 wt% of the alkali extraction combined liquid, and filtering to obtain an alkali extraction filtrate; S22, taking the acid extraction combined liquid, adding activated carbon to the acid extraction combined liquid, wherein the activated carbon added is 0.5 wt % to 1.5 wt % of the acid extraction combined liquid, filtering to remove the activated carbon, and obtaining an acid extraction filtrate; S23, combining the alkali extraction filtrate and the acid extraction filtrate to form the functional component mixture.

4. The method for extracting Rhododendron chinense according to claim 1, wherein In S12, the amount of the ethanol aqueous solution is 4500 ml to 5500 ml of the ethanol aqueous solution per 1000 g of Rhododendron chinense.

5. The method for extracting Rhododendron chinense according to claim 1, wherein In S0, the extraction object is the leaves or flowers of Rhododendron chinense.

6. Use of an extract in the preparation of Xiaokechuan granules, characterized in that: The following steps are involved: Taking an extract, which is a mixed solution of functional ingredients according to any one of claims 1 to 5; The functional component mixed solution is spray-dried after recovering ethanol to obtain extract powder, and the extract powder is mixed with an appropriate amount of dextrin for adjustment, and granules are prepared, dried, granulated, sieved, mixed, and packaged into bags.

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