A method for extracting polyphenol characteristic components from polygonatum cyrtonema hua by using ultrasonic-assisted natural eutectic solvent and application thereof

Abstract

The application discloses a method for extracting polyphenol characteristic components of Polygonatum cyathopetalum by using ultrasonic-assisted natural low-eutectic solvent and application thereof, and first uses the natural low-eutectic solvent combined with ultrasonic extraction to prepare the polyphenol extract of Polygonatum cyathopetalum, establishes a method for efficiently extracting polyphenol compounds in Polygonatum cyathopetalum by using the environment-friendly natural low-eutectic solvent as an extraction solvent, can improve the extraction efficiency, and obtains the extract with 17 main characteristic polyphenol compounds, has better antioxidant and uric acid reducing effects, has a wide application prospect in the development of functional products, and has the advantages of green environment protection, strong stability, simple operation, small solvent consumption, short extraction time, low production cost, replacement of traditional organic solvents, applicability to large-scale industrial production, and solution to the problems of high toxicity, poor biodegradability and low extraction efficiency of the existing traditional organic solvent as an extraction agent.

Description

Technical fields:

[0001] This invention relates to the field of natural product extraction and application technology, specifically to a method for extracting characteristic polyphenolic components of Polygonatum cyrtonema using ultrasound-assisted natural eutectic solvents and its application. Background technology:

[0002] Polygonatum cyrtonema Hua, the tuber of a perennial herbaceous plant belonging to the genus Polygonatum in the family Liliaceae, is widely distributed in southern my country. It grows in forests, thickets, or shady mountain slopes at altitudes of 500–2100 m. It is sweet and neutral in nature, and its medicinal properties are associated with the spleen, lungs, and kidneys. It is believed to replenish qi and yin, strengthen the spleen, moisten the lungs, and benefit the kidneys. Polygonatum cyrtonema Hua is one of the three medicinal sources of Polygonatum listed in the Pharmacopoeia of the People's Republic of China (2020 edition), and it is also classified as a forest-derived plant that is both food and medicine.

[0003] Polygonatum multiflorum is rich in various active ingredients, including polysaccharides, steroids, saponins, flavonoids, alkaloids, lignans, and phytosterols. Modern pharmacological studies have also found that Polygonatum multiflorum has antioxidant, anti-fatigue, anti-aging, hypoxia-resistance, immune-regulating, lipid-lowering, blood glucose-lowering, anti-tumor, antibacterial, anti-inflammatory, antiviral, and memory-enhancing effects. Among them, polysaccharides, as the most important active ingredient in Polygonatum multiflorum, are an important indicator for evaluating the quality of Polygonatum in the pharmacopoeia. The Chinese Pharmacopoeia (2020 edition) stipulates that the polysaccharide content of Polygonatum multiflorum should not be less than 7.0%, and currently, the most research and application of Polygonatum multiflorum mainly focuses on total polysaccharides. In addition, flavonoids are also special components in Polygonatum multiflorum, and research mainly focuses on content analysis and optimization of extraction and preparation processes. However, there are few reports on research on total polyphenols in Polygonatum multiflorum.

[0004] Natural deep eutectic solvents (NADES) are a novel type of green solvent with great potential to replace traditional organic solvents for the efficient extraction of natural active substances. They are eutectic solvents composed of natural components such as primary metabolites, and are considered a third liquid phase naturally present in organisms, independent of water and lipids. They are homogeneous liquid mixtures composed of hydrogen bond donors and acceptors in a specific ratio. Currently, NADES can be prepared using various methods such as thermal mixing, vacuum evaporation, freeze-drying, or grinding, which are simple to operate and require minimal equipment. Based on the compounds used in the synthesis of NADES, they can be classified into five major categories: ionic liquid, neutral, neutral acidic, neutral basic, and amino acid-containing NADES. Their formation process involves combining natural compounds such as sugars, organic acids, amino acids, and choline derivatives in a specific molar ratio under certain conditions to form a low-melting-point liquid mixture. The formation principle is that the hydrogen bonds formed between hydrogen bond donors and acceptors delocalize the charges, leading to a decrease in the melting point of the mixture, ultimately presenting a liquid eutectic system at room temperature. NADES possesses characteristics such as being green and safe, having a low melting point (lower than any single component), good thermal stability, high chemical stability, and low volatility. Furthermore, because the hydroxyl or carboxyl groups present in the component structure can form hydrogen bonds with the extract, it shows great advantages in natural product extraction and organic synthesis. For example, existing technologies provide cases of extracting polyphenols from different plants using eutectic solvents. See the published literature: Wang Xiaoyi, Li Peikun, Li Jinhong, et al. Ultrasonic-assisted eutectic solvent extraction of rose polyphenols and their antioxidant activity [J]. Food Research and Development, 2022, 43(8):8. This discloses the efficient and rapid extraction of polyphenols from roses using ultrasonic-assisted DES method and compares it with the traditional ethanol extraction method. The optimal extraction conditions for rose polyphenols by DES method were obtained through single-factor optimization experiments: choline chloride-lactic acid (molar ratio 1:2) with 30% water content was the best extractant, the solid-liquid ratio was 1:40 (g / mL), the ultrasonic time was 10 min, the ultrasonic power was 400 W, the ultrasonic temperature was 50 ℃, and the extraction was performed twice. Under these conditions, the extract yield of rose polyphenols was 136.20 ± 1.23 mg / g.

[0005] However, different plants have different structures and compositions, and the types and proportions of polyphenols they contain also vary. Therefore, the eutectic solvent formulations and extraction conditions suitable for extracting polyphenols from different plants are not consistent, and there are significant individual differences. Currently, there is no publicly available scheme for extracting polyphenols from Polygonatum cyrtonema using eutectic solvents. Summary of the Invention:

[0006] The purpose of this invention is to provide a method and its application for extracting polyphenolic characteristic components of Polygonatum cyrtonema using ultrasound-assisted natural eutectic solvents. This invention is the first to utilize natural eutectic solvents combined with ultrasound extraction to prepare Polygonatum cyrtonema polyphenol extracts, solving the problems of high toxicity, poor biodegradability, and low extraction efficiency of existing traditional organic solvents as extractants.

[0007] This invention is achieved through the following technical solutions:

[0008] A method for extracting polyphenolic characteristic components from Polygonatum cyrtonema using ultrasound-assisted natural eutectic solvents includes the following steps: adding Polygonatum cyrtonema powder to a prepared natural eutectic solvent at a ratio of 1:10 to 30 g / mL; employing ultrasound-assisted extraction under the following conditions: temperature 25℃ to 45℃, power 50W to 200W, and extraction time 5 min to 35 min; after extraction, centrifuging the sample solution at 3500 rpm to 5000 rpm for 5 min to 15 min, obtaining the supernatant as the Polygonatum cyrtonema extract; and then drying to obtain the extract sample. The natural eutectic solvent comprises betaine and lactic acid, prepared by mixing betaine and lactic acid at a molar ratio of 2:1 to 1:2 and heating and stirring at 80-100℃ until a homogeneous, clear, and transparent liquid is obtained without crystallization at room temperature; and then adding water according to the mass ratio.

[0009] Preferably, the preparation method of Polygonatum multiflorum powder is as follows: Take freshly collected Polygonatum multiflorum samples, wash and slice them, dry them at 40℃~60℃, pulverize them, pass them through a 60~80 mesh sieve, place them in a plastic bag and put them in a desiccator for later use.

[0010] Preferably, the water content of the natural eutectic solvent is 20wt% to 50wt%.

[0011] Most preferably, the water content in the natural eutectic solvent prepared from betaine and lactic acid is 50%, the ratio of Polygonatum odoratum powder sample to natural eutectic solvent is 1:19 g / mL, and the extraction time is 35 min.

[0012] Preferably, the drying method is freeze drying or spray drying.

[0013] The polyphenolic components of Polygonatum odoratum extract were analyzed using ultra-high performance liquid chromatography-quadrupole / time-of-flight mass spectrometry (UPLC-Q-TOF-MS / MS). Chromatographic conditions: Agilent UPLC 1290, Waters BEHC182.1*100mm 1.7µm column, flow rate 0.3mL / min, injection volume 5µL, mobile phase A was 0.1% formic acid aqueous solution, mobile phase B was acetonitrile solution, gradient elution: 0–8 min, 95%–79% A; 8–17 min, 79%–78% A; 17–20 min, 78%–60% A; 20–30 min, 60%–55% A; 30–40 min, 55%–27% A; 40–45 min, 27%–0% A; 45–50 min, 0%–95% A; 50–55 min, 95% A. Mass spectrometry conditions: Agilent Q-TOF6550, electrospray ionization source, mass spectrometry scanning range: 50–1500 m / z (first stage), sheath gas temperature: 350 °C, sheath gas flow rate: 12 L / min.

[0014] The screening yielded 17 characteristic polyphenolic components in the extract, with the following structural formulas:

[0015]

[0016] Currently, the main focus of research on polyphenols in Polygonatum odoratum is on total content detection. Furthermore, reports on the extraction of Polygonatum components using eutectic solvents have not included comparative analysis of characteristic compounds. Meanwhile, based on liquid chromatography-mass spectrometry (LC-MS), compounds (2), (7), (9), (10), (13), and (14), which contain polyphenolic hydroxyl structures, were discovered for the first time in this class of substances. This further demonstrates that the ultrasound-assisted natural eutectic solvent can effectively extract polyphenols from Polygonatum odoratum.

[0017] The polyphenolic extract obtained by this invention also has better antioxidant and uric acid-lowering effects. Therefore, this invention also protects the use of the extract in the preparation of antioxidants and uric acid-lowering drugs.

[0018] The beneficial effects of this invention are as follows: This invention is the first to utilize natural eutectic solvents combined with ultrasonic extraction to prepare polyphenolic extracts of Polygonatum cyrtonema. By screening NADES of different systems, a green and efficient method for extracting polyphenolic compounds from Polygonatum cyrtonema using environmentally friendly natural eutectic solvents as extraction solvents is established. This method not only improves extraction efficiency, but also yields extracts containing 17 main characteristic polyphenolic compounds, exhibiting better antioxidant and uric acid-lowering effects. It has broad application prospects in the development of functional products. Furthermore, compounds (2), (7), (9), (10), (13), and (14), which have polyphenolic hydroxyl structures, are also discovered for the first time in this class of substances. In addition, the solvent is green and environmentally friendly, highly stable, simple to operate, requires less solvent, has a short extraction time, and low production cost. It can replace traditional organic solvents and is suitable for large-scale industrial production, solving the problems of high toxicity, poor biodegradability, and low extraction efficiency of existing traditional organic solvents as extractants. Attached image description:

[0019] Figure 1 This is a response surface plot of the extraction process of polyphenol characteristic components.

[0020] Figure 2 The sample's DPPH free radical scavenging effect

[0021] Figure 3 The sample's scavenging effect on ABTS free radicals

[0022] Figure 4 This represents the inhibitory effect of the sample on xanthine oxidase. Detailed implementation method:

[0023] The following is a further description of the invention, but not a limitation thereof.

[0024] The examples first screened different types of eutectic solvents for polyphenolic substances in Polygonatum cyrtonema, and optimized the extraction conditions, including extraction temperature, extraction time, and material-liquid ratio, to obtain the optimal preparation process. The antioxidant and other effects of the prepared samples were evaluated, aiming to establish a method for extracting and preparing characteristic components of Polygonatum cyrtonema using natural eutectic solvents.

[0025] To better explain and facilitate understanding of the present invention, it will be described in detail with reference to the accompanying drawings and specific embodiments. The following examples are further illustrations of the present invention, but not limitations thereof.

[0026] Sample and solution preparation

[0027] Take freshly collected Polygonatum odoratum samples, wash and slice them, dry them at 60℃, pulverize them, pass them through an 80-mesh sieve, place them in a plastic bag and put them in a desiccator for later use.

[0028] Based on preliminary experimental results, lactic acid was selected as the hydrogen donor and betaine as the hydrogen acceptor, and a natural eutectic solvent was prepared with a molar ratio of 1:2. The mixture was placed in a magnetic stirrer and stirred at 85°C until a homogeneous, clear, and transparent liquid was obtained. It was then diluted with 30% (v / v) deionized water and set aside for later use.

[0029] Sample extraction and preparation process

[0030] Weigh approximately 0.5g of the sample of Polygonatum odoratum powder into a stoppered Erlenmeyer flask, add extraction solvent according to a material-to-liquid ratio of 1:20 (g / mL), weigh the sample, and extract with ultrasonic assistance at room temperature for 30 min to make up for the lost mass. Centrifuge the sample at 4000 r / min for 20 min, and take an appropriate amount of supernatant for analysis of total polyphenol content.

[0031] Total polyphenol detection method

[0032] Accurately transfer 1.0 mL of the test solution, add 5.0 mL of 10% Folin-Ciocalteu reagent, shake well, then add 4.0 mL of 7.5% sodium carbonate solution, and dilute to the mark with water. Incubate at room temperature for 60 min, and measure the absorbance at 765 nm. Use gallic acid as a reference to plot a standard curve.

[0033] The betaine-lactic acid eutectic solvent (DES) was selected through preliminary experiments. S To obtain optimal extraction conditions, DESs (diethylstilbestrol) was used as the extraction solvent for total polyphenols in Polygonatum cyrtonema. The solvent composition and extraction conditions were systematically investigated. The investigated factors included the water content of the betaine-lactic acid eutectic solvent (30%, 40%, 50%, 60%, 70%), extraction time (10 min, 20 min, 30 min, 40 min, 50 min), and solid-liquid ratio (1:10 g / mL, 1:15 g / mL, 1:20 g / mL, 1:25 g / mL, 1:30 g / mL).

[0034] Based on the central composite design principle, and using the total polyphenol yield as the response value, a three-factor, three-level response surface methodology was designed using Design-Expert software. Based on the single-factor experiments, the factor levels were determined to be solvent water content, extraction time, and solid-liquid ratio. The factors and levels are shown in Table 1, the experimental group design and results are shown in Table 2, and the analysis of variance is shown in Table 3.

[0035] Table 1 Factor Level Table

[0036]

[0037] Table 2 Experimental Design

[0038]

[0039]

[0040] Table 3. Analysis of Variance Table

[0041]

[0042]

[0043] Note: ** indicates extremely significant level (P<0.01); * indicates significant level (P<0.05).

[0044] The table shows that the regression model has a p-value < 0.01, indicating high significance and thus the model is valid. The model's lack-of-fit term p = 0.2572 > 0.05, indicating insignificance, meaning there's no need to fit higher-order terms. This further demonstrates that using this model to analyze the effects of various factors on the total polyphenol extraction yield is reasonable. The analysis of variance results show that the model's linear terms X1 and X2, interaction term X1X3, and quadratic term X1... 2 X2 2 X3 2 The effect of the linear term X3 on the yield of total polyphenols was extremely significant (P<0.01), while the effects of the linear term X3, the interaction terms X1X2, and X2X3 on the yield of total polyphenols in Polygonatum cyrtonema were not significant (P>0.05). Furthermore, the R-squared value of the experimental model... 2 =0.9877, indicating that the predictive power and consistency of the experimental results are good, R = adj 2 =0.9718, indicating that the model can explain 97.18% of the response value variation, demonstrating good model fit and small experimental error. In this model, the coefficient of variation (CV) = 1.54%, indicating small random error in the experiment, which also demonstrates the sufficiency and rationality of the model, accurately reflecting the experimental results and possessing high precision. A comprehensive analysis of the F-values ​​and P-values ​​of each factor shows that the order of influence of factors on the total polyphenol yield is: solvent moisture content > extraction time > solid-liquid ratio. Among the interaction factors, X1 and X3 have the greatest impact on the total polyphenol yield of Polygonatum odoratum. Using Design Expert 10.0.4 to fit the values ​​in Table 4, a quadratic multinomial regression model was obtained: Y = 0.70 + 0.030X1 + 0.026X2 - 4.625E-003X3 - 8.250E-003X1X2 - 0.028X1X3 - 0.011X2X3 - 0.047X1 2 -0.035X2 2 -0.064X3 2Analysis showed that the optimal extraction conditions for total polyphenols from Polygonatum cyrtonema using betaine-lactic acid as the best eutectic solvent were a solvent water content of 50%, an extraction time of 35 min, and a solid-liquid ratio of 1:19 (g / mL). Under these conditions, the predicted yield of total polyphenols from Polygonatum cyrtonema was 0.706%. Three verification experiments confirmed that the total polyphenol yield from Polygonatum cyrtonema was (0.706 ± 0.002)%, close to the predicted value.

[0045] exist Figure 1 The response surface plot shows that the shape of the surface reflects the influence of the interaction between the points on the response surface on the extraction yield of total polyphenols from Polygonatum cyrtonema. The greater the slope of the surface, the greater the influence; the smaller the slope, the smaller the influence. If the contour lines are circular, it indicates that the interaction between the two factors is not significant. The plot shows that the contour lines of each extraction factor are approximately elliptical, indicating a certain interaction between the factors. Within a certain range, the polyphenol yield initially increases and then decreases with changes in solvent moisture content, extraction time, and solid-liquid ratio. The interaction between solvent moisture content and solid-liquid ratio has a more significant impact on the extraction yield of total polyphenols from Polygonatum cyrtonema, which is consistent with the results of the analysis of variance.

[0046] Based on the polyphenol extract samples obtained from the above optimization experiments, the chemical composition of the polyphenols in the extracts was analyzed by ultra-high performance liquid chromatography-quadrupole / time-of-flight mass spectrometry (UPLC-Q-TOF-MS / MS). Chromatographic conditions: Agilent ultra-high performance liquid chromatograph 1290, column: Waters BEH C182.1*100mm 1.7um, flow rate: 0.3mL / min, injection volume: 5uL, mobile phase A: 0.1% formic acid aqueous solution, mobile phase B: acetonitrile solution, gradient elution: 0–8 min, 95%–79% A; 8–17 min, 79%–78% A; 17–20 min, 78%–60% A; 20–30 min, 60%–55% A; 30–40 min, 55%–27% A; 40–45 min, 27%–0% A; 45–50 min, 0%–95% A; 50–55 min, 95% A. Mass spectrometry conditions: Agilent Q-TOF6550, electrospray ionization source, mass spectrometry scan range: 50–1500 m / z (first stage), sheath gas temperature: 350 °C; sheath gas flow rate: 12 L / min. The analytical results show the composition of the main characteristic polyphenolic compounds, as shown in Table 4.

[0047] Table 4. Key Characteristics of Polyphenolic Compounds

[0048]

[0049]

[0050] UPLC-Q-TOF-MS / MS analysis showed that the natural eutectic solvent system based on betaine-lactic acid can effectively extract and prepare polyphenolic substances. Seventeen main characteristic polyphenolic compounds were screened, with the following structural formulas:

[0051]

[0052] Currently, the main focus of research on polyphenols in Polygonatum odoratum is on total content detection. Furthermore, reports on the extraction of Polygonatum components using eutectic solvents have not included comparative analysis of characteristic compounds. Meanwhile, based on liquid chromatography-mass spectrometry (LC-MS), compounds (2), (7), (9), (10), (13), and (14) with polyphenolic hydroxyl structures were discovered for the first time in this class of substances. This further demonstrates that the ultrasound-assisted natural eutectic solvent can effectively extract polyphenols from Polygonatum odoratum.

[0053] The extract was prepared according to the optimized process described above, concentrated under reduced pressure, and then freeze-dried to obtain the extract sample. Alternatively, the DES extraction solvent was replaced with 60% ethanol and water, and samples were prepared using the same extraction process. Sample solutions of different concentration gradients were prepared, and in vitro antioxidant and xanthine oxidase activity inhibition assays were conducted.

[0054] DPPH free radical scavenging test

[0055] Take 2.0 mL of sample solutions of different concentrations and place them in a 10 mL stoppered colorimetric tube. Add an equal volume of 0.1 mmol / L DPPH ethanol solution, mix well, and react in the dark for 30 min. Then, use a UV spectrophotometer to detect the absorbance value at 517 nm (A1). Mix 2 mL of extraction solvent and 2 mL of DPPH well and measure its absorbance value (A2). Use the mixture of 2 mL of DPPH and 2 mL of ethanol as a control group and measure its absorbance value (A0).

[0056]

[0057] Depend on Figure 2 It can be seen that the scavenging effect of different types of Polygonatum sibiricum extracts (DES extract, ethanol extract and water extract) on DPPH free radicals increases with the increase of sample concentration. However, within the range of sample concentrations investigated, the scavenging effect of DES extract on DPPH free radicals is significantly higher than that of ethanol extract and water extract.

[0058] ABTS free radical scavenging test

[0059] ABTS stock solution was prepared by mixing 7.4 mM ABTS solution and 2.6 mM potassium persulfate solution at a 1:1 volume ratio and reacting in the dark for 12 h. The concentration of the ABTS stock solution was then adjusted with 200 mM phosphate buffer solution (pH 7.4) to achieve an absorbance of 0.700 ± 0.02 at 734 nm. Then, 0.05 mL of sample extracts of different concentrations were added to 4 mL of ABTS working solution, mixed, and reacted in the dark at room temperature for 6 min. The absorbance was measured at 734 nm (A1). A blank control group was prepared by replacing the sample solution with the extraction solvent, and the mixed solution samples were prepared according to the above steps, and their absorbance was measured (A0).

[0060]

[0061] Depend on Figure 3 It can be seen that the scavenging effect of different types of Polygonatum odoratum extracts (DES extract, ethanol extract and water extract) on ABTS free radicals increases with the increase of sample concentration. Although the scavenging effect of different samples on ABTS free radicals is similar at the initial concentration, as the sample concentration increases, within the range of sample concentrations investigated, the scavenging effect of DES extract on ABTS free radicals is higher than that of ethanol extract and water extract.

[0062] Xanthine oxidase activity inhibition test

[0063] Take 0.6 mL of phosphate buffer solution (0.10 mol / L, pH = 8.5), 0.2 mL of xanthine solution (2.0 mmol / L), and 0.1 mL of sample solutions of different concentrations and mix them thoroughly in a 1.5 mL centrifuge tube; then add 0.2 mL of xanthine oxidase solution (0.1 U / mL) and react in a water bath at 25 °C for 30 min. After the reaction is complete, add 0.2 mL of HCl solution (1.0 mol / L) to terminate the reaction. Measure the absorbance at 290 nm.

[0064]

[0065] In the formula: A1: absorbance value of the sample group with and without enzyme;

[0066] A2: Absorbance value of the sample group without enzyme or enzyme addition;

[0067] A3: Absorbance value of the enzyme-added sample group;

[0068] A4: Absorbance value of the sample group without enzyme addition.

[0069] Depend on Figure 4It can be seen that the inhibitory effect of different samples on xanthine oxidase increases with increasing concentration. Among them, the inhibitory effect of DES extract on xanthine oxidase is significantly higher than that of ethanol extract and water extract.

[0070] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

1. A method for extracting polyphenol characteristic components from Polygonatum cyathophorum Hua by using ultrasonic-assisted natural deep eutectic solvent, characterized in that, There are 17 polyphenolic components, with the following structural formulas: ； The method includes the following steps: adding Polygonatum cyrtonema powder to a prepared natural eutectic solvent, with a powder-to-solvent ratio of 1:19 g / mL; ultrasonic-assisted extraction is performed under the following conditions: temperature 25℃~45℃, power 50W~200W, and extraction time 35 min; after extraction, the sample solution is centrifuged at 3500rpm~5000rpm for 5min~15min, and the resulting supernatant is the Polygonatum cyrtonema extract; then drying to obtain the extract sample; the method also includes the following step: analyzing the polyphenolic chemical components of the Polygonatum cyrtonema extract using ultra-high performance liquid chromatography-quadrupole / time-of-flight mass spectrometry, with the following chromatographic conditions: Agilent ultra-high performance liquid chromatograph 1290, and Waters column. BEHC18, flow rate 0.3 mL / min, injection volume 5 μL, mobile phase A is 0.1% formic acid aqueous solution, mobile phase B is acetonitrile solution, gradient elution: 0–8 min, 95%–79% A; 8–17 min, 79%–78% A; 17–20 min, 78%–60% A; 20–30 min, 60%–55% A; 30–40 min, 55%–27% A; 40–45 min, 27%–0% A; 45–50 min, 0%–95% A; 50–55 min… In, 95% A; Mass spectrometry conditions: Agilent Q-TOF6550, electrospray ionization source, mass spectrometry scanning range: first stage 50~1500 m / z, sheath gas temperature 350℃; sheath gas flow rate 12 L / min; The natural eutectic solvent components include betaine and lactic acid, and the water content of the natural eutectic solvent is 50 wt%; The preparation method is as follows: betaine and lactic acid are mixed at a molar ratio of 1:2, and heated and stirred at 85℃ until a homogeneous, clear, and transparent liquid is formed and no crystals precipitate at room temperature, and water is added according to the mass ratio.

2. The method according to claim 1, characterized in that, The preparation method of Polygonatum multiflorum powder is as follows: Take freshly collected Polygonatum multiflorum samples, wash and slice them, dry them at 40℃~60℃, pulverize them, pass them through a 60~80 mesh sieve, place them in a plastic bag and put them in a desiccator for later use.

3. The method according to claim 1, characterized in that, The drying method is freeze drying or spray drying.

4. The application of the 17 polyphenolic components with the structures shown below obtained by the method of claim 1 in the preparation of uric acid-lowering drugs: 。

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