Method for preparing puerarin with effects of removing acnes, controlling oil and shrinking pores based on molecular imprinting technology and application of puerarin

Abstract

The invention relates to a method for preparing puerarin with effects of removing acnes, controlling oil and shrinking pores based on a molecular imprinting technology and application, and belongs to the technical field of biological medicines and cosmetics. The puerarin preparation method provided by the invention comprises the following steps: (1) adding radix puerariae powder into an ethanol water solution, carrying out heating reflux extraction, filtering, then repeatedly extracting, and combining filtrate to obtain an extracting solution; (2) adding cyclodextrin into the extracting solution to react, concentrating to remove alcohol, replenishing water, and filtering to obtain an inclusion compound; (3) adsorbing the inclusion compound by adopting a polyamide chromatographic column, eluting for the first time by adopting pure water, and eluting for the second time and the third time by adopting an ethanol water solution of cyclodextrin; and (4) concentrating the obtained third eluent, removing alcohol, replenishing water, adsorbing by using a polyamide chromatographic column, washing by using pure water, eluting by using high-concentration ethanol, concentrating, and drying to obtain puerarin. The preparation method is simple, high-purity puerarin can be obtained, the recovery rate is high, and the product has good effects and can be used in the fields of cosmetics and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedicine and cosmetics, and in particular to a method and application of preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology. Background Art

[0002] Lobed Kudzuvine Root is the tuberous root of the vine plant Pueraria lobata. Since ancient times, the stem bark fiber, root and other parts of Pueraria lobata have been widely used. According to the Compendium of Materia Medica by Li Shizhen of the Ming Dynasty, Pueraria lobata is sweet, pungent, neutral and non-toxic, and can be used to treat typhoid fever, irritability, thirst, vomiting blood due to heart heat, bleeding due to heat toxicity, and drunkenness. Pueraria lobata extract contains active ingredients such as soybean (soybean) glycosides, soybean aglycone, and puerarin, and has extremely high value.

[0003] Molecular Imprinting Technology (MIT) is a technology that uses molecular imprinting polymers (MIPs) to simulate the interaction between enzymes and substrates or antibodies and antigens to specifically identify imprinted molecules (also known as template molecules). Polyamide can specifically adsorb flavonoids through hydrogen bonding, while cyclodextrin can include compounds with specific chemical structures through hydrophobic interaction and hydrogen bonding.

[0004] In the pueraria extract, the molecular structures of puerarin, daidzin, 3-hydroxypuerarin, 3'-methoxypuerarin, etc. are relatively similar, and it is difficult to distinguish them using molecular imprinting technology with a single template. For example, Cheng Shaoling et al. prepared puerarin molecular imprinting polymers using puerarin as the template molecule, acrylamide as the monomer, and ethylene glycol dimethacrylate (EDMA) as the crosslinker, but the molecular imprinting polymers could not separate puerarin, daidzin, and 3-hydroxypuerarin. The use of polyamide alone can only separate the isoflavones, dihydroflavonols, flavones, and flavonols in the pueraria extract by category, but cannot accurately separate a specific component, such as puerarin in pueraria isoflavones. A single cyclodextrin can only screen specific compounds that are insoluble in water and whose molecular structure and molecular weight meet the cyclodextrin inclusion conditions, and cyclodextrin cannot be separated.

[0005] Therefore, developing a molecular imprinting technology to further separate other structural molecules, improve separation and purification efficiency, and increase yield to obtain puerarin raw materials with higher purity is of great significance to product research and development and production in the fields of biomedicine, cosmetics, etc. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method and application of preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology. The puerarin product prepared by the puerarin preparation method provided by the present invention has high purity and high recovery rate, and can well separate raw material impurities, and has high application value in the fields of biomedicine, cosmetics, etc.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] In a first aspect, the present invention provides a method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology, comprising the following steps:

[0009] (1) adding kudzu root powder to ethanol aqueous solution for heating and refluxing extraction, filtering, then repeating the heating and refluxing extraction, filtering, and combining the filtrate to obtain an extract;

[0010] (2) adding cyclodextrin to the extract to react, then concentrating to remove alcohol, adding water, and filtering to obtain an inclusion complex aqueous solution;

[0011] (3) adsorbing the inclusion complex aqueous solution using a polyamide chromatography column, eluting with pure water for the first time, eluting with eluent A for the second time, eluting with eluent B for the third time, and collecting the third eluate;

[0012] The eluent A and the eluent B are ethanol aqueous solutions of cyclodextrin, wherein the mass concentration of cyclodextrin is 4-5%; the volume concentration of ethanol in the eluent A solvent is 20-25%, and the volume concentration of ethanol in the eluent B solvent is 25-30%;

[0013] (4) The third eluate is concentrated to remove alcohol, replenish water, adsorbed by a polyamide chromatography column, rinsed with pure water, and then eluted with eluent C to obtain a puerarin eluate, which is then concentrated and dried to obtain the puerarin; the eluent C is an ethanol-water solution, wherein the volume concentration of ethanol is 90-100%.

[0014] The present invention adopts the above-mentioned extraction-inclusion-column chromatography elution-deinclusion steps to prepare high-purity puerarin using kudzu root powder as a raw material. First, an extract of kudzu root powder is obtained by heating and reflux twice, and then cyclodextrin is added to the extract to include puerarin. This step can significantly improve the separation effect of puerarin and daidzein and 3-hydroxypuerarin, and at the same time improve the recovery rate of puerarin.

[0015] After the inclusion complex is obtained, column chromatography elution is performed: the first elution is performed with pure water to remove excess cyclodextrin, water-soluble kudzu root extract and some non-flavonoid impurities; the second elution is performed with eluent A containing 4-5% cyclodextrin in a 20-25% ethanol aqueous solution, aiming to remove 3-hydroxypuerarin, 3'-methoxypuerarin, daidzein and puerarin apiglycoside, which have higher polarity than puerarin, and the third elution is performed with eluent B containing 4-5% cyclodextrin in a 25-30% ethanol aqueous solution, to elute the cyclodextrin inclusion complex of puerarin. When the cyclodextrin concentrations in eluents A and B are not suitable, the separation effect of the chromatography column may be significantly deteriorated, the recovery rate may be significantly reduced, and the purity of puerarin in the product may be significantly reduced.

[0016] The obtained cyclodextrin inclusion complex of puerarin is washed with pure water to remove cyclodextrin, and finally puerarin is eluted with an ethanol aqueous solution of a specific concentration to obtain a puerarin eluate, which is further treated to obtain a high-purity puerarin product. The puerarin preparation method based on molecular imprinting technology provided by the present invention has low raw material cost, can efficiently prepare a puerarin product with a purity of more than 95.64%, and a recovery rate of more than 98%, and has high application value in the manufacturing and research and development of cosmetics, biomedicine and other fields.

[0017] Preferably, in step (1), the temperature of the heating reflux extraction is 60-90° C. and the time is 80-100 min.

[0018] Preferably, in step (1), the volume concentration of ethanol in the ethanol aqueous solution is greater than 70%.

[0019] Preferably, in step (1), the volume ratio of the kudzu root powder to the ethanol aqueous solution is 1 kg: (13-15) L.

[0020] Preferably, in step (2), the mass ratio of cyclodextrin to kudzu root powder is (0.5-1): 1. Filtration after inclusion can remove most of the water-insoluble compounds that cannot be included by cyclodextrin.

[0021] Preferably, in step (2), the reaction time is 3.5-4.5 h.

[0022] Preferably, in step (3), the amount of pure water used in the first elution is 2-4 times the column volume, the amount of eluent A used in the second elution is 3-5 times the column volume, and the amount of eluent B used in the third elution is 3-5 times the column volume.

[0023] Preferably, in step (3), the mass concentration of cyclodextrin in the eluent A is 4%, and the volume concentration of ethanol is 20%; the mass concentration of cyclodextrin in the eluent B is 5%, and the volume concentration of ethanol is 30%. When this elution condition is adopted, the obtained puerarin product has the best analytical purification effect and high purity.

[0024] Preferably, in step (4), the amount of pure water used for pure water washing is 2-3 times the column volume, and the amount of eluent C used is 3-5 times the column volume.

[0025] Further preferably, in the step (4), after the third eluate is concentrated to remove alcohol and replenish water, the soluble solid content is 5%.

[0026] In a second aspect, the present invention provides the use of the method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology, which is applied in the fields of biomedicine and cosmetics.

[0027] Preferably, puerarin is prepared according to the above-mentioned puerarin preparation method based on molecular imprinting technology, and the puerarin is used in cosmetics, and the mass concentration of puerarin in the cosmetics is 0.5-1%. The puerarin product prepared by the preparation method of the present invention can be further used in the preparation of cosmetics, etc., and has long-lasting and good effects of removing acne, controlling oil, and shrinking pores.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The invention adopts a preparation method based on molecular imprinting technology of extraction-cyclodextrin inclusion-column chromatography elution-deinclusion, and regulates the concentration of the eluent, so as to achieve efficient preparation of puerarin products using pueraria root powder, and the obtained puerarin products have high purity, low impurity content and good recovery rate; the prepared puerarin is compounded to further prepare cosmetics and other products to give full play to the effects of acne removal, oil control and pore shrinkage, and has high application value in the fields of biomedicine, cosmetics and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the HPLC result of the puerarin product prepared in Example 3;

[0031] Figure 2 This is the HPLC result of the puerarin product prepared in Comparative Example 3;

[0032] Figure 3 This is a comparison chart of the pore shrinking, acne removal and oil control effects at different times after the subjects used the puerarin compound emulsion 1 (puerarin content 0.5%) prepared by the present invention;

[0033] Figure 4 The figure is a comparison chart of the pore shrinking, acne removal and oil control effects at different times after the subjects used the puerarin compound emulsion 2 (puerarin content 1%) prepared by the present invention. DETAILED DESCRIPTION

[0034] In order to better illustrate the purpose, technical scheme and advantages of the present invention, the present invention will be further described below in conjunction with specific examples. The test methods used in the following examples are conventional methods unless otherwise specified; the materials and reagents used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0035] Example 1

[0036] The present invention provides an embodiment of a method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology. The method for preparing puerarin based on molecular imprinting technology described in this embodiment is as follows:

[0037] S1, extraction: 1 kg of raw material Pueraria powder was mixed with 75% v / v ethanol aqueous solution at a ratio of 1 kg: 14 L, heated under reflux at 70°C for 80 min, filtered, and the steps were repeated once, and the filtrate was combined to obtain an extract;

[0038] S2, inclusion: add 600g cyclodextrin to the extract of step S1, react for 4 hours, concentrate to remove alcohol, add water, and then filter to obtain an inclusion complex aqueous solution;

[0039] S3, column chromatography: adsorbing the inclusion complex aqueous solution of step S2 through a polyamide chromatography column, and then eluting the chromatography column for the first time with 3 times the column volume of pure water; then eluting the chromatography column for the second time with a 5% cyclodextrin ethanol solution containing 20% ​​v / v ethanol in an amount of 3 times the column volume; finally, eluting the chromatography column for the third time with a 5% cyclodextrin ethanol solution containing 30% v / v ethanol in an amount of 3 times the column volume, and collecting the third eluate;

[0040] S4, de-inclusion: the third eluate of step S3 is concentrated to remove alcohol, and water is added to make the soluble solid content 5%, and then adsorbed by a polyamide chromatography column, and then the chromatography column is washed with 2 times the column volume of pure water, and finally 90% v / v ethanol is used to elute the chromatography column in an amount of 3 times the column volume to collect the puerarin eluate;

[0041] S5, finished product: the puerarin eluate of step S4 is concentrated and then dried to obtain a puerarin product.

[0042] Example 2

[0043] The present invention provides an embodiment of a method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology. The method for preparing puerarin based on molecular imprinting technology described in this embodiment is as follows:

[0044] S1, extraction: 1 kg of raw material Pueraria powder was mixed with 75% v / v ethanol aqueous solution at a ratio of 1 kg: 14 L, heated under reflux extraction at 90°C for 100 min, filtered, and the steps were repeated once, and the filtrate was combined to obtain an extract;

[0045] S2, inclusion: add 1000g cyclodextrin to the extract of step S1, react for 4 hours, concentrate to remove alcohol, add water, and then filter to obtain an inclusion complex aqueous solution;

[0046] S3, column chromatography: adsorbing the inclusion complex aqueous solution of step S2 through a polyamide chromatography column, and then eluting the chromatography column for the first time with 5 times the column volume of pure water; then eluting the chromatography column for the second time with a 4% cyclodextrin ethanol solution containing 25% v / v ethanol in an amount of 5 times the column volume; finally, eluting the chromatography column for the third time with a 5% cyclodextrin ethanol solution containing 25% v / v ethanol in an amount of 5 times the column volume, and collecting the third eluate;

[0047] S4, de-inclusion: the third eluate of step S3 is concentrated to remove alcohol, and water is added to make the soluble solid content 5%, and then adsorbed by a polyamide chromatography column, and then the chromatography column is rinsed with 3 times the column volume of pure water, and finally 95% v / v ethanol is used to elute the chromatography column in an amount of 3 times the column volume to collect the puerarin eluate;

[0048] S5, finished product: the puerarin eluate of step S4 is concentrated and then dried to obtain a puerarin product.

[0049] Example 3

[0050] The present invention provides an embodiment of a method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology. The method for preparing puerarin based on molecular imprinting technology described in this embodiment is as follows:

[0051] S1, extraction: 1 kg of raw material Pueraria powder was mixed with 75% v / v ethanol aqueous solution at a ratio of 1 kg: 14 L, heated under reflux extraction at 80°C for 90 min, filtered, and the steps were repeated once, and the filtrate was combined to obtain an extract;

[0052] S2, inclusion: add 800g cyclodextrin to the extract of step S1, react for 4 hours, concentrate to remove alcohol, add water, and then filter to obtain an inclusion complex aqueous solution;

[0053] S3, column chromatography: adsorbing the inclusion complex aqueous solution of step S2 through a polyamide chromatography column, and then eluting the chromatography column for the first time with 5 times the column volume of pure water; then eluting the chromatography column for the second time with a 4% cyclodextrin ethanol solution containing 20% ​​v / v ethanol in an amount of 5 times the column volume; finally, eluting the chromatography column for the third time with a 5% cyclodextrin ethanol solution containing 30% v / v ethanol in an amount of 5 times the column volume, and collecting the third eluate;

[0054] S4, de-inclusion: the third eluate of step S3 is concentrated to remove alcohol, and water is added to make the soluble solid content 5%, and then adsorbed by a polyamide chromatography column, and then the chromatography column is rinsed with 3 times the column volume of pure water, and finally 90% v / v ethanol is used to elute the chromatography column in an amount of 3 times the column volume to collect the puerarin eluate;

[0055] S5, finished product: the puerarin eluate of step S4 is concentrated and then dried to obtain a puerarin product.

[0056] Comparative Example 1

[0057] The only difference between Comparative Example 1 and Example 1 is that no cyclodextrin is added as the eluent in the second and third elutions in step S3.

[0058] Comparative Example 2

[0059] The difference between Comparative Example 2 and Example 1 is that cyclodextrin inclusion is not added in step S2.

[0060] Comparative Example 3

[0061] The only difference between Comparative Example 3 and Example 1 is that in the second and third elutions in step S3, the mass concentration of cyclodextrin in the eluent is changed to 1%.

[0062] Comparative Example 4

[0063] The only difference between Comparative Example 4 and Example 1 is that in the second and third elutions in step S3, the mass concentration of cyclodextrin in the eluent is changed to 9%.

[0064] Effect Example 1

[0065] In order to explore the purity of puerarin obtained by the puerarin preparation method based on molecular imprinting technology provided by the present invention, high performance liquid chromatography was used to detect the contents of 3-hydroxypuerarin, daidzein and puerarin in the finished products of the above embodiments and comparative examples: the conditions of HPLC were as follows: chromatographic column: ODS C18 chromatographic column, mobile phase: methanol: 36% acetic acid: water = 25:3:72, flow rate: 1.0 mL / min, detection wavelength: 247 nm.

[0066] The contents of 3-hydroxypuerarin, daidzin and puerarin in each embodiment and comparative example are compared with the raw material puerarin powder as shown in Table 1; the HPLC result of puerarin prepared in Example 3 is shown in Table 1. Figure 1 ; Comparative Example 3 prepared the product HPLC results as shown Figure 2 .

[0067] It can be seen from Table 1 that the puerarin preparation method based on molecular imprinting technology provided in Examples 1-3 of the present invention can realize the preparation of high-purity puerarin (purity ≥ 95.64%) using puerarin powder, and the puerarin recovery rate is as high as 98-99.8%, which is significantly better than the results in the comparative example.

[0068] From the comparison of the contents of the components in Examples 1-3, it can be seen that the preparation scheme in Example 3 can better separate daidzein and 3-hydroxypuerarin under specific elution conditions, thereby improving the purity of puerarin; while the preparation scheme in Example 2 has a slightly lower separation degree, but can achieve the highest puerarin recovery rate.

[0069] By comparing Example 1 with Comparative Examples 1 and 2, it can be seen that: in Comparative Example 1, the elution conditions of the column chromatography are changed, the cyclodextrin in the eluent is removed, and only the corresponding concentration of ethanol aqueous solution is used for elution. Although Pueraria powder with a purity of 96.44% can be obtained, the recovery rate is extremely low, the preparation efficiency is very poor, and it contains more other impurities (such as 3'-methoxypuerarin, puerarin apiside, soybean aglycone, genistein, etc.); in Comparative Example 2, the inclusion step is changed and cyclodextrin is not used for inclusion. After the subsequent elution step, the separation effect of puerarin in the product is significantly deteriorated, the purity of puerarin is reduced to only 31.7%, and the product recovery rate is greatly reduced.

[0070] From the comparison between Example 1 and Comparative Examples 3 and 4, it can be seen that: in Comparative Example 3, the mass concentration of the eluent cyclodextrin in the second and third elutions in the column chromatography step was reduced to outside the specified range, which significantly reduced the separation effect of daidzein and 3-hydroxypuerarin, and the purity of puerarin was reduced to 62.68%, while the product recovery rate was significantly reduced; in Comparative Example 4, the mass concentration of the eluent cyclodextrin in the second and third elutions in the column chromatography step was increased to outside the specified range. Although daidzein and 3-hydroxypuerarin were not detected in the obtained product, the puerarin content was only 57.14%, the content of other impurities was extremely high, and the recovery rate was significantly reduced.

[0071] In summary, the puerarin preparation method based on molecular imprinting technology adopted in the present invention significantly improves the puerarin preparation efficiency through the extraction-inclusion-column chromatography-deinclusion steps: the cyclodextrin inclusion strategy is adopted to significantly improve the purity and recovery rate of the product puerarin; the eluent with the addition of cyclodextrin is adopted to greatly improve the recovery rate of puerarin; in the column chromatography step, the eluent is added with a specific concentration of cyclodextrin, which can ensure a good separation effect of daidzein, 3-hydroxypuerarin and other impurities from puerarin, thereby obtaining high-purity puerarin and achieving a high recovery rate.

[0072] Table 1 Comparison of puerarin products and raw material contents obtained in Examples and Comparative Examples

[0073]

[0074] Effect Example 2

[0075] In order to explore the use and efficacy of the puerarin preparation method based on molecular imprinting technology provided by the present invention in cosmetics, the puerarin prepared in Example 1 was compounded with a conventional emulsion (mass concentration: 0.03% disodium EDTA, 4% glycerol, 2% propylene glycol, 0.03% hyaluronic acid, 0.5% 1,2-hexanediol and the remainder water) to make the mass concentration of puerarin 0.5% and 1%, respectively, to prepare emulsion 1 and emulsion 2 correspondingly.

[0076] The above lotions 1 and 2 were tested for their pore-shrinking, acne-removing and oil-control effects as follows:

[0077] (1) Subjects: A total of 30 subjects, including 10 males and 20 females, aged 18 to 40 years old, with an average age of 28 years old, met the voluntary inclusion criteria.

[0078] All enrolled subjects met the following inclusion and exclusion criteria:

[0079] a. Selection criteria

[0080] Healthy women / men, aged between 18 and 40 years old; those with a certain amount of acne on their facial skin, which cannot be nodules or cysts that are difficult to improve with clinical preparations; the facial skin should be free of birthmarks, scratches, white spots, pigmented moles, and other phenomena that may affect the trial; they can cooperate well with the experimenters and maintain a regular life during the study; they can read and understand all the contents of the informed consent form and voluntarily sign the informed consent form; they agree not to use any cosmetics, drugs, and health products that may affect the results during the trial.

[0081] b. Exclusion criteria

[0082] Those who have used preparations that affect sebum secretion in the past month; those who have used antihistamines in the past week or immunosuppressants in the past month; those who have applied any anti-inflammatory drugs to the test site in the past two months; subjects with inflammatory skin diseases that have not been clinically cured; patients with insulin-dependent diabetes; patients with asthma or other chronic respiratory diseases being treated; those who have received anti-cancer chemotherapy in the past 6 months; patients with immunodeficiency or autoimmune diseases; breastfeeding or pregnant women; those who have had bilateral mastectomy and bilateral axillary lymph node resection; those whose skin scars, pigmentation, atrophy, port-wine stains, and skin blemishes on the test site may affect the determination of the test results; those who are participating in other clinical trial researchers; those with highly sensitive constitutions; non-voluntary participants or those who cannot complete the specified content as required by the trial.

[0083] (2) Testing process

[0084] The subjects were acclimatized to the environment of 21±1℃ and 50+10%RH for at least 30 minutes before using the lotion (applied on the face). The following tests were performed 0h before use, 4 and 8 hours after use, and on the 14th and 28th days of long-term use:

[0085] The facial image camera system VISIACR is used to measure the cheek area and calculate the pore area ratio. If the pore area ratio is significantly reduced, it means that the pores are reduced.

[0086] A multifunctional skin imager is used to measure the cheek area to obtain the volume of acne bulges. If the volume of acne is reduced, the acne is effectively relieved.

[0087] The facial image camera system VISIACR was used to measure the cheek area to obtain the volume percentage and amount of porphyrin oil. The smaller the value, the lower the oil content.

[0088] When the test value result after using the test sample on the test side is significantly better than the result on the control side (before use) (P<0.05), the test sample is deemed to have the corresponding efficacy; otherwise, the test sample is deemed to have no corresponding efficacy.

[0089] (3) Test results

[0090] The results of pore-shrinking, acne-removing and oil-controlling effects of lotion 1 and 2 are as follows: Figure 3 , Table 2, and Figure 4 , Table 3.

[0091] The significant marking method in the results of Tables 2 and 3 is as follows:

[0092] "ns" indicates no statistical difference, P>0.05; "*" indicates significant difference, 0.01≤P<0.05;

[0093] "**" indicates a very significant difference, where 0.001 < P < 0.01; "***" indicates an extremely significant difference, where P < 0.001.

[0094] From Tables 2, 3 and Figure 3 and 4 it can be seen that: For the cosmetics formulated with high-purity puerarin prepared by the puerarin preparation method based on molecular imprinting technology provided by the present invention, when the subjects used it for 4 hours, it had the effects of treating acne and controlling oil on the skin; when the subjects used it for 8 hours, it had the effects of treating acne and controlling oil on the skin; when the subjects used it for 14 days, it had the effects of treating acne, controlling oil and shrinking pores on the skin; when the subjects used it for 28 days, it had the effects of treating acne, controlling oil and shrinking pores on the skin; compared with the concentration of 0.5%, when the compounding concentration of the puerarin product was 1% by mass concentration, the effects of long-term pore shrinking and oil control were better.

[0095] (4) Human skin safety

[0096] During the use by the subjects, no adverse events such as erythema, papules, infiltration, etc. occurred. When the puerarin prepared by the puerarin preparation method based on molecular imprinting technology of the present invention was used in cosmetics at a mass concentration of 0.5 - 1%, it could ensure human safety and had no adverse reactions.

[0097] In summary, the puerarin preparation method based on molecular imprinting technology provided by the present invention has high application value in both the biomedical and cosmetic fields.

[0098] Table 2 Results of efficacy evaluation after using the emulsion containing 0.5% puerarin prepared by the present invention

[0099]

[0100]

[0101] Table 3 Results of efficacy evaluation after using the emulsion containing 1% puerarin prepared by the present invention

[0102] Time after use 4h 8h 14d 28d Pore ​​area change% -5.75 -1.15 -11.63 -20.93 Pore ​​Minimization Efficacy Evaluation ns ns *** ** Acne volume change rate % -18.37 -36.73 -63.27 -81.63 Acne Treatment Efficacy Evaluation1 *** *** *** *** Change rate of acne number % -10.18 -10.71 -49.46 -82.68 Acne Treatment Efficacy Evaluation 2 *** *** *** *** Change rate of porphyrin oil volume percentage % -9.73 -7.50 -10.41 -20.63 Oil control efficacy evaluation 1 * * ** ** Porphyrin oil quantity change rate % -9.39 -6.03 -10.26 -21.76 Oil control efficacy evaluation 2 ** * ** ***

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology, characterized in that: The following steps are involved: (1) adding kudzu root powder to ethanol aqueous solution for heating and refluxing extraction, filtering, then repeating the heating and refluxing extraction, filtering, and combining the filtrate to obtain an extract; (2) adding cyclodextrin to the extract to react, then concentrating to remove alcohol, adding water, and filtering to obtain an inclusion complex aqueous solution; (3) adsorbing the inclusion complex aqueous solution using a polyamide chromatography column, eluting with pure water for the first time, eluting with eluent A for the second time, eluting with eluent B for the third time, and collecting the third eluate; The eluent A and the eluent B are ethanol aqueous solutions of cyclodextrin, wherein the mass concentration of cyclodextrin is 4-5%; the volume concentration of ethanol in the eluent A solvent is 20-25%, and the volume concentration of ethanol in the eluent B solvent is 25-30%; (4) The third eluate is concentrated to remove alcohol, replenish water, adsorbed by a polyamide chromatography column, rinsed with pure water, and then eluted with eluent C to obtain a puerarin eluate, which is then concentrated and dried to obtain the puerarin; the eluent C is an ethanol-water solution, wherein the volume concentration of ethanol is 90-100%.

2. The method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology according to claim 1, characterized in that: In the step (1), the temperature of the heating reflux extraction is 60-90° C. and the time is 80-100 min.

3. The method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology according to claim 1, characterized in that: In the step (1), the volume concentration of ethanol in the ethanol aqueous solution is greater than 70%.

4. The method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology according to claim 2, characterized in that: In the step (1), the volume ratio of the kudzu root powder to the ethanol aqueous solution is 1 kg: (13-15) L.

5. The method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology according to claim 1, characterized in that: In the step (2), the mass ratio of cyclodextrin to the kudzu root powder is (0.5-1):

1.

6. The method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology according to claim 1, characterized in that: In the step (2), the reaction time is 3.5-4.5 hours.

7. The method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology according to claim 1, characterized in that: In the step (3), the amount of pure water used in the first elution is 2-4 times the column volume, the amount of eluent A used in the second elution is 3-5 times the column volume, and the amount of eluent B used in the third elution is 3-5 times the column volume.

8. The method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology according to claim 1, characterized in that: In the step (3), the mass concentration of cyclodextrin in the eluent A is 4%, and the volume concentration of ethanol is 20%; the mass concentration of cyclodextrin in the eluent B is 5%, and the volume concentration of ethanol is 30%.

9. The method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology according to claim 1, characterized in that: In the step (4), the amount of pure water used for pure water washing is 2-3 times the column volume, and the amount of eluent C used is 3-5 times the column volume.

10. Use of the method for preparing puerarin with acne-removing, oil-controlling and pore-shrinking effects based on molecular imprinting technology according to any one of claims 1 to 9, characterized in that: Used in the fields of biomedicine and cosmetics.

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