Method for improving water solubility and antibacterial activity of honokiol
By synthesizing bi- and mono-side-chain HK-AA derivatives, the water solubility and antibacterial activity of magnolol were improved, solving the problems of poor water solubility and inadequate antibacterial effect, and enabling its widespread clinical application.
Patent Information
- Application Number
- CN202510906698.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-02
- Publication Date
- 2025-10-31
AI Technical Summary
Honokiol (HK) has poor water solubility and poor antibacterial effect, which limits its widespread clinical application.
The water solubility of HK-AA derivatives with both double and single side chains was improved by synthesizing them. The antibacterial activity was determined by CLSI standard, and the MIC value was recorded. The water solubility was determined by saturated solution method. The synthetic route was optimized to improve its solubility.
It significantly improved the water solubility and antibacterial activity of magnolol, meeting the needs of clinical application.
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Figure CN120865010A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of pharmaceutical chemistry, and in particular to a method for improving the water solubility and antibacterial activity of magnolol. Background Technology
[0002] With the widespread use of antibiotics, bacterial resistance has become an increasingly serious problem, especially resistance to traditional antibiotics, posing a significant challenge to clinical treatment. Against this backdrop, the search for novel, highly effective, and low-toxicity antibacterial drugs has become a hot topic in current pharmaceutical research. Antimicrobial peptides (AMPs), as a class of natural or synthetic small molecules with cationic and hydrophobic amphiphilic structures, are considered highly promising antibiotic alternatives due to their unique antibacterial mechanisms and lower risk of resistance. AMPs can act on bacterial cell membranes, killing bacteria by forming pores or disrupting the integrity of the cell membrane. This mechanism of action significantly reduces the probability of bacteria developing resistance. However, despite exhibiting good antibacterial activity, problems such as hemolytic toxicity, cytotoxicity, instability, and high synthesis and purification costs limit their large-scale clinical application.
[0003] Honokiol (HK), as a natural polyphenol small molecule compound, has a certain antibacterial effect against Gram-positive bacteria, mainly methicillin-resistant Staphylococcus aureus (MRSA). However, its poor water solubility and unsatisfactory antibacterial effect limit its widespread clinical application. Summary of the Invention
[0004] The purpose of this invention is to provide a method for improving the water solubility and antibacterial activity of magnolol, aiming to solve the technical problem that magnolol (HK) has poor water solubility and poor antibacterial effect, which limits its widespread clinical application.
[0005] To achieve the above objectives, the present invention employs a method for improving the water solubility and antibacterial activity of magnolol, comprising the following steps: Obtain the raw materials and conditions for the synthesis of bilateral chain HK-AA derivatives, and prepare the product according to the synthetic route; Obtain the raw materials and conditions for synthesizing single-side-chain HK-AA derivatives, and prepare the product according to the synthetic route; According to CLSI standards, the in vitro antibacterial activity of HK-AA derivatives was determined and the MIC values were recorded. The water solubility of HK-AA derivatives was determined using the saturated solution method, and the solubility data were recorded.
[0006] Specifically, the key lies in the steps of obtaining the synthetic raw materials and conditions for the bilateral chain HK-AA derivative, and preparing the product according to the synthetic route: HK, Boc-L-amino acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were dissolved in dry dichloromethane; Add triethylamine dropwise and stir at room temperature to allow the reaction to proceed overnight; The reactants were dissolved in ethyl acetate and then washed sequentially with 0.20 N hydrochloric acid solution, water, and saturated sodium bicarbonate solution. The oily intermediate was dissolved in a 1 N dioxane hydrochloride solution and stirred overnight at room temperature. Remove the solvent under reduced pressure, dissolve the residue in ethyl acetate, and then remove the solvent under reduced pressure again. Repeat the above operation three times to obtain the crude product. The product was dried under reduced pressure using an oil pump, then rinsed with a solution, and finally dried in a vacuum drying oven for 2 hours to obtain compound HA-1-7.
[0007] Specifically, this involves the steps of obtaining the synthetic raw materials and conditions for single-side-chain HK-AA derivatives, and preparing the product according to the synthetic route: S1a, Boc-protected amino acids, and EDCI were dissolved in dry dichloromethane. Triethylamine was added dropwise, and after the addition was complete, the mixture was stirred at room temperature and allowed to react overnight. After HK disappeared as monitored by TLC, the reaction solvent was removed under reduced pressure, and the reactants were dissolved in ethyl acetate. The organic layer was then washed successively with 0.2 N hydrochloric acid solution (2 × 2.00 mL), water (3 × 2.00 mL), and saturated sodium bicarbonate solution (3 × 2.00 mL). The organic layer was dried with anhydrous sodium sulfate to obtain an oily intermediate. The oily intermediate was dissolved in a 1N dioxane hydrochloride solution and stirred overnight at room temperature. Remove the solvent under reduced pressure, dissolve the residue with ethyl acetate, and then remove the solvent under reduced pressure again. Repeat the above operation three times to obtain the crude product. The product was dried under reduced pressure using an oil pump, then rinsed with a solution, and finally dried in a vacuum drying oven for 2 hours to obtain compound HA-8-13.
[0008] In this study, the in vitro antibacterial activity of HK-AA derivatives was determined according to CLSI standards, and the MIC values were recorded. Bacteria were cultured in a culture medium, single colonies were selected from solid culture medium, isolated and inoculated into LB culture medium to prepare a bacterial suspension, and cultured overnight at 37°C with shaking. Dilute the culture medium at a ratio of 1:100 to prepare fresh LB culture medium, and shake for 6 hours until the bacteria reach the exponential growth phase; The MIC value was determined by the broth dilution method. Different concentrations of the test compound were serially diluted 2-fold in sterile MH culture medium, and the final volume in a 96-well plate was 100 μL. Adjust the mid-logarithmic bacterial culture to approximately 10 using MHII culture medium. 6 CFU / mL was transferred to 100 μL and added to each well of the working plate. Then, 100 μL of the adjusted culture medium was added to each well and incubated at 37°C for 20 h. The minimum concentration of a test compound that inhibits bacterial growth as observed by the naked eye is the MIC.
[0009] In the step of determining the water solubility of HK-AA derivatives and recording the solubility data according to the saturated solution method: The water solubility of compounds was analyzed using the saturated solution method; Accurately measure 10 mL of distilled water, slowly add the compound, stir well, and observe whether it dissolves. If dissolution occurs, continue adding the compound being tested until the solubility limit is reached, then stop adding. Record the mass of the added compound and calculate its solubility; Record the water solubility data of HK-AA derivatives at different temperatures and analyze the effect of improving water solubility.
[0010] In this study, the in vitro antibacterial activity of HK-AA derivatives was determined according to CLSI standards, and the MIC values were recorded. The culture medium is either LB medium or MH medium.
[0011] Among the steps, in recording the water solubility data of HK-AA derivatives at different temperatures and analyzing the water solubility improvement effect: Record the water solubility data of HK-AA derivatives at 25℃ and 50℃.
[0012] This invention discloses a method for improving the water solubility and antibacterial activity of magnolol. First, the synthetic raw materials and conditions for a double-sided chain HK-AA derivative are obtained, and the product is prepared according to the synthetic route. Next, the synthetic raw materials and conditions for a single-sided chain HK-AA derivative are obtained, and the product is prepared according to the synthetic route. Then, the in vitro antibacterial activity of the HK-AA derivative is determined according to the CLSI standard, and the MIC value is recorded. Finally, the water solubility of the HK-AA derivative is determined using the saturated solution method, and the solubility data is recorded. Using the above method, the water solubility and antibacterial activity of magnolol can be improved, meeting the needs of clinical applications. Attached Figure Description
[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0014] Figure 1 This is a flowchart of the steps of the method for improving the water solubility and antibacterial activity of magnolol according to the present invention.
[0015] Figure 2 This is a flowchart of the steps of the method for improving the water solubility and antibacterial activity of magnolol according to the present invention.
[0016] Figure 3 This is a flowchart of the steps of the method for improving the water solubility and antibacterial activity of magnolol according to the present invention.
[0017] Figure 4 This is a flowchart of the steps of the method for improving the water solubility and antibacterial activity of magnolol according to the present invention.
[0018] Figure 5 This is a flowchart of the steps of the method for improving the water solubility and antibacterial activity of magnolol according to the present invention.
[0019] Figure 6 This is a synthesis diagram of compound HA-1-7 of the present invention.
[0020] Figure 7 This is a synthesis diagram of compound HA-8-12 of the present invention.
[0021] Figure 8 This is a synthesis diagram of the amino acid-HK derivative of the present invention.
[0022] Figure 9 This is a table showing the antibacterial activity of compound HA-8-12 of the present invention.
[0023] Figure 10 This is a table showing the antibacterial activity of compound HA-1-7 of the present invention.
[0024] Figure 11 This is a table showing the water solubility of compound HA-1-12 of the present invention.
[0025] Figure 12 This is a graph showing the relationship between the solubility of HA-1 and temperature according to the present invention. Detailed Implementation
[0026] Please see Figures 1-12 The present invention provides a method for improving the water solubility and antibacterial activity of magnolol, comprising the following steps: S100: Obtain the raw materials and conditions for the synthesis of the bilateral chain HK-AA derivative, and prepare the product according to the synthetic route.
[0027] In this embodiment, the raw materials and conditions for synthesizing the bilateral HK-AA derivative are obtained, and the product is prepared according to the synthetic route. The specific process is as follows: S101: Dissolve HK, Boc-L-amino acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in dry dichloromethane; S102: Add triethylamine dropwise and stir at room temperature to allow the reaction to proceed overnight; S103: Dissolve the reactants in ethyl acetate and then wash them sequentially with 0.20 N hydrochloric acid solution, water, and saturated sodium bicarbonate solution; S104: Dissolve the oily intermediate in a 1 N dioxane hydrochloride solution and react overnight at room temperature with stirring. S105: Remove the solvent under reduced pressure, dissolve the residue with ethyl acetate, and then remove the solvent under reduced pressure again. Repeat the above operation three times to obtain the crude product. S106: The product was dried under reduced pressure using an oil pump, then rinsed with a solution, and finally dried in a vacuum drying oven for 2 hours to obtain compound HA-1-7.
[0028] In the above process, during the preparation of compound HA-1-7, firstly, HK (100.00 mg, 0.38 mmol), Boc-L-amino acid (0.94 mmol), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (179.73 mg, 0.94 mmol) were dissolved in dry dichloromethane (5.00 mL). Then, triethylamine (75.85 mg, 0.75 mmol) was added dropwise, and the mixture was stirred at room temperature overnight. Next, the reactants were dissolved in ethyl acetate and washed successively with 0.20 N hydrochloric acid solution (2 × 2.00 mL), water (3 × 2.00 mL), and saturated sodium bicarbonate solution (3 × 2.00 mL). Finally, the oily intermediate was dissolved in 1 N dioxane hydrochloride solution (5.00 mL). The reaction was carried out overnight at room temperature with stirring in mL. The solvent was then removed under reduced pressure, the residue was dissolved in ethyl acetate, and the solvent was removed again under reduced pressure. This process was repeated three times to obtain the crude product. Finally, the product was dried under reduced pressure using an oil pump, washed with a solution (n-hexane:ethyl acetate = 5:1), and dried in a vacuum drying oven for 2 h to obtain compound HA-1-7, which was a white or light yellow solid. Additionally, the bi-side-chain HK derivative HA-1-7 was obtained by condensing HK with a Boc-protected amino acid in the presence of an EDCI condensing agent, followed by deprotection of the Boc protecting group. The product was presented as a hydrochloride salt, with yields maintained at a high level of 55-90%. This synthesis was simple and purification was convenient. All the above compounds were foamy solids under vacuum drying and needed to be stored in a cool, dry, and sealed environment. To verify the effect of the size and steric hindrance of the side-chain substituent R on the antibacterial activity of the bi-side-chain HK-AA derivative, the antibacterial activity of the compounds in Table 9 was determined. The antibacterial activity of HK-1 against MRSA was MIC = 2-12. μg / mL, showed weak or no significant antibacterial activity against other bacteria, and HK-2-7 showed no significant antibacterial activity.
[0029] S200: Obtain the raw materials and conditions for the synthesis of single-side-chain HK-AA derivatives, and prepare the product according to the synthetic route.
[0030] In this embodiment, the raw materials and conditions for synthesizing the single-side-chain HK-AA derivative are obtained, and the product is prepared according to the synthetic route. The specific process is as follows: S201: Dissolve S1a, Boc-protected amino acids, and EDCI in dry dichloromethane; S202: Add triethylamine dropwise, and after the addition is complete, stir at room temperature and let the reaction proceed overnight; S203: After HK disappeared as monitored by TLC, the reaction solvent was removed under reduced pressure, and the reactants were dissolved in ethyl acetate. S204: Washed sequentially with 0.2 N hydrochloric acid solution, water and saturated sodium bicarbonate solution, the organic layer was dried with anhydrous sodium sulfate to obtain an oily intermediate; S205: Dissolve the oily intermediate in a 1 N dioxane hydrochloride solution and react overnight at room temperature with stirring. S206: Remove the solvent under reduced pressure, dissolve the residue with ethyl acetate, and then remove the solvent under reduced pressure again. Repeat the above operation three times to obtain the crude product. S207: The product was dried under reduced pressure using an oil pump, then rinsed with a solution, and finally dried in a vacuum drying oven for 2 hours to obtain compound HA-8-13.
[0031] In the above process, during the preparation of compound HA-8-13, firstly, S1a (100.00 mg, 0.26 mmol), Boc-protected amino acid (0.39 mmol), and EDCI (75.39 mg, 0.39 mmol) were dissolved in dry dichloromethane (5.00 mL). Then, triethylamine (26.58 mg, 0.26 mmol) was added dropwise. After the addition was complete, the mixture was stirred at room temperature and reacted overnight. Next, after the disappearance of hydroxyl radical (HK) was monitored by TLC, the reaction solvent was removed under reduced pressure, and the reactants were dissolved in ethyl acetate. Then, the reactants were washed successively with 0.2 N hydrochloric acid solution (2 × 2.00 mL), water (3 × 2.00 mL), and saturated sodium bicarbonate solution (3 × 2.00 mL). The organic layer was dried over anhydrous sodium sulfate to obtain an oily intermediate. Subsequently, the oily intermediate was dissolved in 1 N dioxane hydrochloride solution (5.00 mL). The reaction was carried out overnight at room temperature in mL, and the solvent was removed under reduced pressure. The residue was dissolved in ethyl acetate and the solvent was removed under reduced pressure again. The above operation was repeated three times to obtain the crude product. Finally, the product was dried under reduced pressure under oil pump, and then washed with a solution (n-hexane:ethyl acetate = 5:1). The product was dried in a vacuum drying oven for 2 h to obtain compound HA-8-13, which is a white or light yellow solid. In addition, the single-side chain HK derivative HA-8-13 was obtained by using TES-protected HK (S1a) as a starting material, which was condensed with Boc-protected amino acid in a condensing agent (EDCI) and then the Boc and TES were removed. The synthesis method was basically the same as that of the above double-side chain HK derivative. The product was also presented as a hydrochloride salt with a yield of 38% to 75%. The above compounds are foamy solids under vacuum drying conditions. They readily absorb moisture and become partially viscous in room temperature air, and exhibit poor thermal stability. Therefore, these compounds, being foamy solids under vacuum drying conditions, need to be stored in a cool, dry environment in a sealed container. To verify the effect of the size and steric hindrance of the side-chain substituent R1 on the antibacterial activity of the single-side-chain HK-AA derivatives, the antibacterial activity of the compounds in Table 10 was determined. Compound HA-8 showed only weak antibacterial activity against Staphylococcus aureus strains (MIC = 256 μg / mL), while compounds HA-9-12, with larger side-chain substituent sizes and greater steric hindrance, did not show significant antibacterial activity (MIC > 256 μg / mL).
[0032] S300: Determine the in vitro antibacterial activity of HK-AA derivatives according to CLSI standards and record the MIC value.
[0033] In this embodiment, the in vitro antibacterial activity of the HK-AA derivative was determined according to the CLSI standard, and the MIC value was recorded. The specific process is as follows: S301: Culture bacteria in a culture medium, select single colonies from solid culture medium, isolate and inoculate them into LB culture medium to prepare a bacterial suspension, and culture at 37°C with shaking overnight; S302: Dilute the culture medium at a ratio of 1:100 to prepare fresh LB culture medium, and shake for 6 hours until the bacteria reach the exponential growth phase; S303: The MIC value was determined by the broth dilution method. Different concentrations of the test compound were continuously diluted 2 times in sterile MH culture medium, and the final volume in the 96-well plate was 100 μL. S304: Adjust the mid-logarithmic bacterial culture to approximately 10 using MHII broth. 6 CFU / mL was transferred to 100 μL and added to each well of the working plate. Then, 100 μL of the adjusted culture medium was added to each well and incubated at 37°C for 20 h. S305: The lowest concentration of a test compound that inhibits bacterial growth as observed by the naked eye is the MIC.
[0034] In the above process, during the determination of the antibacterial activity of the compound, bacteria were first cultured in a culture medium, either LB or MH. Single colonies were selected from the solid culture medium, isolated, and inoculated into LB culture to prepare a bacterial suspension, which was then shaken and cultured overnight at 37°C. Then, the culture was diluted 1:100 to prepare fresh LB culture, and shaking was continued for 6 hours until the bacteria reached the exponential growth phase. Next, the MIC (minimum inhibitory concentration) value was determined using the broth dilution method. Specifically, different concentrations of the test compound were serially diluted 2-fold in sterile MH culture, and the final volume in a 96-well plate was adjusted to 100 μL. Then, the mid-logarithmic bacterial suspension was adjusted to approximately 10^6 CFU / mL using MHII culture medium (Mueller Hinton II), and 100 μL was transferred to each well of the working plate. Then, 100 μL of the adjusted culture medium was added to each well, and the plate was incubated at 37°C for 20 hours. The lowest concentration of the test compound that inhibited bacterial growth as observed by the naked eye was the MIC.
[0035] S400: Determine the water solubility of HK-AA derivatives using the saturated solution method and record the solubility data.
[0036] In this embodiment, the water solubility of the HK-AA derivative was determined and the solubility data was recorded according to the saturated solution method. The specific process is as follows: S401: The water solubility of the compound was analyzed using the saturated solution method; S402: Add the compound to be tested until the solubility limit is reached, then stop adding; S403: Record the mass of the added compound and calculate its solubility; S404: Record the water solubility data of HK-AA derivatives at different temperatures and analyze the water solubility improvement effect.
[0037] In the above process, during the analysis of the water solubility of HK-AA derivatives, firstly, the saturated solution method was used to analyze the water solubility of the compounds. Then, 10 mL of distilled water was accurately measured and placed in a suitable container. The HK-AA derivative to be tested was slowly added while stirring with a stirring device. The dissolution of the compound was carefully observed. If dissolution was observed, the compound was slowly added until it no longer dissolved regardless of stirring, indicating that the solubility limit had been reached. At this point, the addition was stopped. Next, the mass of the added compound was accurately recorded. The solubility was calculated according to the solubility calculation formula (solubility = mass of solute / volume of solvent, the unit is usually g / 100 mL, etc., which can be adjusted according to the actual situation). Finally, the above operation was repeated under different temperature conditions (such as setting multiple temperature gradients), and the water solubility data of HK-AA derivatives at different temperatures (25℃ and 50℃) were recorded. By comparing and analyzing these data, the water solubility improvement effect was evaluated. In addition, as shown in Table 11, at 25 degrees Celsius, linking amino acid groups can significantly improve the water solubility of magnolol, especially HA-1, whose water solubility reaches 30%. mg / mL, and simultaneously, the water solubility of compound HA-1 at different temperatures was determined, such as Figure 12 As shown, the water solubility of HA-1 gradually increases with increasing temperature, reaching a maximum of 52 mg / mL at 50°C. The water solubility remains unchanged with further increases in temperature.
[0038] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.
Claims
1. A method for improving the water solubility and antibacterial activity of magnolol, characterized in that, Includes the following steps: Obtain the raw materials and conditions for the synthesis of bilateral chain HK-AA derivatives, and prepare the product according to the synthetic route; Obtain the raw materials and conditions for the synthesis of single-side-chain HK-AA derivatives, and prepare the product according to the synthetic route; The in vitro antibacterial activity of HK-AA derivatives was determined according to CLSI standards, and the MIC values were recorded. The water solubility of HK-AA derivatives was determined using the saturated solution method, and the solubility data were recorded.
2. The method for improving the water solubility and antibacterial activity of magnolol as described in claim 1, characterized in that, In the steps of obtaining the synthetic raw materials and conditions for the bilateral chain HK-AA derivative, and preparing the product according to the synthetic route: HK, Boc-L-amino acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride were dissolved in dry dichloromethane; Add triethylamine dropwise and stir at room temperature to allow the reaction to proceed overnight; The reactants were dissolved in ethyl acetate and then washed sequentially with 0.20 N hydrochloric acid solution, water, and saturated sodium bicarbonate solution. The oily intermediate was dissolved in a 1N dioxane hydrochloride solution and stirred overnight at room temperature. Remove the solvent under reduced pressure, dissolve the residue in ethyl acetate, and then remove the solvent under reduced pressure again. Repeat the above operation three times to obtain the crude product. The product was dried under reduced pressure using an oil pump, then rinsed with a solution, and finally dried in a vacuum drying oven for 2 hours to obtain compound HA-1-7.
3. The method for improving the water solubility and antibacterial activity of magnolol as described in claim 1, characterized in that, In the steps of obtaining the synthetic raw materials and conditions for single-side-chain HK-AA derivatives, and preparing the product according to the synthetic route: S1a, Boc-protected amino acids, and EDCI were dissolved in dry dichloromethane. Triethylamine was added dropwise, and after the addition was complete, the mixture was stirred at room temperature and allowed to react overnight. After HK disappeared as monitored by TLC, the reaction solvent was removed under reduced pressure, and the reactants were dissolved in ethyl acetate. The organic layer was then washed successively with 0.2 N hydrochloric acid solution, water, and saturated sodium bicarbonate solution. The organic layer was dried with anhydrous sodium sulfate to obtain an oily intermediate. The oily intermediate was dissolved in a 1 N dioxane hydrochloride solution and stirred overnight at room temperature. Remove the solvent under reduced pressure, dissolve the residue with ethyl acetate, and then remove the solvent under reduced pressure again. Repeat the above operation three times to obtain the crude product. The product was dried under reduced pressure using an oil pump, then rinsed with a solution, and finally dried in a vacuum drying oven for 2 hours to obtain compound HA-8-13.
4. The method for improving the water solubility and antibacterial activity of magnolol as described in claim 1, characterized in that... The in vitro antibacterial activity of HK-AA derivatives was determined according to CLSI standards, and the MIC values were recorded. Bacteria were cultured in a culture medium, single colonies were selected from solid culture medium, isolated and inoculated into LB culture medium to prepare a bacterial suspension, and cultured overnight at 37°C with shaking. Dilute the culture medium at a ratio of 1:100 to prepare fresh LB culture medium, and shake for 6 hours until the bacteria reach the exponential growth phase; The MIC value was determined by the broth dilution method. Different concentrations of the test compound were serially diluted 2-fold in sterile MH culture medium, and the final volume in a 96-well plate was 100 μL. Adjust the mid-logarithmic bacterial culture to approximately 10 using MHII culture medium. 6 CFU / mL was transferred to 100 μL and added to each well of the working plate. Then, 100 μL of the adjusted culture medium was added to each well and incubated at 37°C for 20 h. The minimum concentration of a test compound that inhibits bacterial growth as observed by the naked eye is the MIC.
5. The method for improving the water solubility and antibacterial activity of magnolol as described in claim 1, characterized in that... In the step of determining the water solubility of HK-AA derivatives and recording solubility data according to the saturated solution method: The water solubility of compounds was analyzed using the saturated solution method; Accurately measure 10 mL of distilled water, slowly add the compound, stir well, and observe whether it dissolves. If dissolution occurs, continue adding the compound being tested until the solubility limit is reached, then stop adding. Record the mass of the added compound and calculate its solubility; Record the water solubility data of HK-AA derivatives at different temperatures and analyze the effect of improving water solubility.
6. The method for improving the water solubility and antibacterial activity of magnolol as described in claim 4, characterized in that... The in vitro antibacterial activity of HK-AA derivatives was determined according to CLSI standards, and the MIC values were recorded. The culture medium is either LB medium or MH medium.
7. The method for improving the water solubility and antibacterial activity of magnolol as described in claim 5, characterized in that, In the steps of recording the water solubility data of HK-AA derivatives at different temperatures and analyzing the water solubility improvement effect: Record the water solubility data of HK-AA derivatives at 25℃ and 50℃.