Process for the preparation of myrtle extract and myrtle extract

Abstract

The application discloses a preparation method of myrtle extract and the myrtle extract, and comprises the following steps: S1, mixing myrtle fruit powder and a natural eutectic solvent under heating, wherein the natural eutectic solvent comprises a hydrogen bond donor and a hydrogen bond acceptor; S2, performing ultrasonic treatment on the mixture in the step S1; and S3, performing filtration on the ultrasonic-treated mixture, and obtaining the myrtle fruit extract from the filtrate. According to the preparation method, the combination of the eutectic solvent and the ultrasonic treatment technology is used, so that the solubility of the myrtle fruit powder in the natural eutectic solvent is improved. In the extraction process, the active components of the myrtle fruit powder are protected by the natural eutectic solvent, so that the active components are prevented from being destroyed or invalid, and the prepared myrtle extract has a high content of effective components.

Description

Technical Field

[0001] This application belongs to the field of plant extraction technology, specifically relating to a method for preparing myrtle extract and the myrtle extract itself. Background Technology

[0002] Myrtle (Rhodomyrtus tomentosa), also known as purslane, is widely distributed in the subtropical regions of South Asia. The fruit of the myrtle is a berry; when ripe, the skin is purplish-black, and the flesh is purplish-red, juicy, and rich in nutrients.

[0003] Myrtle fruit contains various active ingredients such as polysaccharides, flavonoids, saponins, polyphenols, and anthraquinones, exhibiting antioxidant, anti-aging, anti-inflammatory, antibacterial, and hepatoprotective biological activities. As a plant resource, myrtle has broad development prospects. However, current technologies for extracting the effective components from myrtle fruit often use water, alcohol, or other organic solvents, resulting in low concentrations of effective components in the extracted extracts. This significantly reduces the efficacy of myrtle fruit extracts and limits their application. Summary of the Invention

[0004] In view of this, this application provides a method for preparing myrtle extract and myrtle extract, aiming to improve the effective components in myrtle extract.

[0005] In a first aspect, embodiments of this application provide a method for preparing a myrtle extract, comprising:

[0006] S1. Under heating conditions, myrtle fruit powder is mixed with a natural eutectic solvent, wherein the natural eutectic solvent includes hydrogen bond donors and hydrogen bond acceptors;

[0007] S2. Sonicate the mixture from step S1;

[0008] S3. Filter the ultrasonically treated mixture to obtain myrtle fruit extract from the filtrate.

[0009] According to an embodiment of one aspect of this application, the hydrogen bond donor is selected from one or more combinations of urea and carbohydrate-derived polyols or carboxylic acids.

[0010] According to one embodiment of this application, the hydrogen bond acceptor is selected from one or a combination of several of carboxylates, quaternary ammonium salts, quaternary phosphonium salts, metal chlorides or sugar compounds, and organic alcohols.

[0011] According to an embodiment of one aspect of this application, the carbohydrate-derived polyol or carboxylic acid is selected from lactic acid, DL-malic acid, citric acid, formic acid, acetic acid, oxalic acid, malonic acid, succinic acid, adipic acid, capric acid, azelaic acid, benzoic acid, phenylacetic acid, 3-phenylpropionic acid, levulinic acid, glycerol, 1,3-propanediol, xylitol, D-isosorbitol, D-sorbitol, or combinations thereof.

[0012] According to an embodiment of one aspect of this application, the hydrogen bond acceptor is selected from one or a combination of several of sodium acetate, choline chloride, betaine, L-carnitine, and zinc chloride.

[0013] According to one embodiment of this application, the natural eutectic solvent comprises an organic salt;

[0014] Optionally, the natural eutectic solvent also contains amino acids.

[0015] According to one embodiment of this application, the molar ratio of hydrogen bond donor to hydrogen bond acceptor is 1:(1-30), and can be selected as 1:5.

[0016] According to one embodiment of this application, a method for preparing a natural eutectic solvent includes mixing a hydrogen bond donor and a hydrogen bond acceptor at a temperature of 70°C ± 5°C to obtain a natural eutectic solvent.

[0017] According to an embodiment of one aspect of this application, in step S1, the ratio of the amount of myrtle fruit powder to the amount of natural eutectic solvent added is 1:(20-25)g / mL.

[0018] According to an embodiment of one aspect of this application, step S1, under heating conditions, includes: under water bath heating conditions.

[0019] According to one embodiment of this application, in step S1, the heating temperature is 45-55°C, and can be selected as 50°C.

[0020] According to an embodiment of one aspect of this application, in step S2, the ultrasonic treatment includes applying ultrasonic waves with a power of 600W-700W to the mixture for a duration of 25min±1min.

[0021] According to an embodiment of one aspect of this application, step S3 includes:

[0022] S310. Filter the ultrasonically treated mixture;

[0023] S320. Soak the filtered residue obtained by filtration in the first solvent.

[0024] S330. Wash the soaked filter residue with a second solvent, and then filter it;

[0025] S340. Collect the filtrate obtained in the above steps and combine them, then concentrate to obtain myrtle fruit extract.

[0026] According to an embodiment of one aspect of this application, step S3 further includes:

[0027] Repeat steps S320 and S330 at least once.

[0028] Secondly, embodiments of this application provide a myrtle extract, obtained by the preparation method of the first aspect.

[0029] Compared with the prior art, this application has at least the following beneficial effects:

[0030] The method provided in this application utilizes a natural eutectic solvent with excellent solubility, resulting in superior extraction efficiency. The combined use of the eutectic solvent and ultrasonic treatment technology enhances the solubility of myrtle fruit powder in the natural eutectic solvent. During extraction, the natural eutectic solvent protects the active components of the myrtle fruit powder, preventing their destruction or inactivation, thus leading to a high content of effective components in the myrtle extract obtained by this method. This method not only extracts various active components such as polysaccharides, flavonoids, saponins, polyphenols, anthraquinones, and tannins, but also significantly increases the content of active components in the natural eutectic solvent extract compared to conventional water extracts, exhibiting advantages such as antibacterial and antioxidant properties and a long shelf life. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the implementation regulations of this application, the drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 The total polyphenol content and total flavonoid content in the embodiments and comparative examples of this application are shown;

[0033] Figure 2 The absorbance and DPPH scavenging rate in the embodiments and comparative examples of this application are shown;

[0034] Figure 3 The high-performance liquid chromatogram of the myrtle extract components provided in Example 2 of this application is shown;

[0035] Figure 4 The high-performance liquid chromatogram of the myrtle extract provided in Comparative Example 1 of this application is shown;

[0036] Figure 5 The high-performance liquid chromatogram of the myrtle extract provided in Comparative Example 2 of this application is shown;

[0037] Figure 6 The clinical SLS stimulation-soothing a* value of the soothing cosmetic product of this application is shown;

[0038] Figure 7 The clinical SLS stimulation-relieving a* value change rate of the soothing cosmetic product of this application is shown;

[0039] Figure 8 The TEWL values ​​of the skin transepidermal water loss of the soothing cosmetic product of this application are shown.

[0040] Figure 9 The change rate of transepidermal water loss (TEWL) value of the soothing cosmetic product of this application is shown. Detailed Implementation

[0041] To make the purpose, technical solution, and beneficial technical effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the implementation details described in this specification are merely for illustrative purposes and are not intended to limit the scope of this application.

[0042] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form a range not explicitly stated; and any lower limit can be combined with other lower limits to form a range not explicitly stated, just as any upper limit can be combined with any other upper limit to form a range not explicitly stated. Furthermore, although not explicitly stated, every point or individual value between the endpoints of the range is included within that range. Therefore, each point or individual value can be used as its own lower or upper limit and combined with any other point or individual value or with other lower or upper limits to form a range not explicitly stated.

[0043] In the description of this application, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, and "multiple" in "one or more" means two or more.

[0044] The foregoing description of this application is not intended to describe every disclosed implementation or method. Instead, the following description provides more specific examples of exemplary embodiments. Throughout the application, guidance is provided through a series of embodiments, which can be used in various combinations. The examples listed are merely representative and should not be construed as exhaustive.

[0045] The existing myrtle powder is produced by crushing, extracting, concentrating, purifying, and drying myrtle fruit. Myrtle fruit powder contains various active components such as phenols, polysaccharides, flavonoids, volatile oils, and anthocyanins, and has good skin care effects.

[0046] Currently, water and alcohols in varying proportions are commonly used extraction solvents in the production and research of the active ingredients in myrtle powder. This method has advantages such as readily available raw materials and low toxicity, but it also has problems that urgently need to be addressed, such as a narrow polarity range and low extraction efficiency for certain types of active ingredients.

[0047] Existing natural deep eutectic solvents (NADES) are solvents with physical properties similar to ionic liquids (ILs). Natural deep eutectic solvents are known to be composed of various components such as choline, urea, organic acids, and sugars. Compared to ILs, NADES offers advantages such as being economical and environmentally friendly, including biodegradability, recyclability, low cost, and simple preparation methods. NADES exhibits strong compatibilizing ability for both nonpolar and polar compounds and demonstrates high extraction efficiency for bioactive components. Using NADES to replace traditional solvents in the extraction of bioactive components from plants may potentially lead to even higher extraction efficiency.

[0048] Based on this, the inventors conducted extensive research and discovered that a natural eutectic solvent can be used to extract myrtle powder, which can significantly increase its effective active components, making it superior to traditional dissolution methods. In turn, the synergistic effect of each component enhances the skincare effect.

[0049] Preparation method of myrtle extract

[0050] The first aspect of this application provides a method for preparing myrtle extract, comprising:

[0051] S1. Under heating conditions, myrtle fruit powder is mixed with a natural eutectic solvent, wherein the natural eutectic solvent includes hydrogen bond donors and hydrogen bond acceptors;

[0052] S2. Sonicate the mixture from step S1;

[0053] S3. Filter the ultrasonically treated mixture to obtain myrtle fruit extract from the filtrate.

[0054] According to the embodiments of this application, natural eutectic solvents are typically stable solvents formed by the melting of two or more substances through intermolecular hydrogen bonds. Using them for extraction can improve the stability of phenolic substances and anthocyanins in myrtle fruit extract. Furthermore, natural eutectic solvents can be used as components of myrtle fruit extract, and in subsequent use, they can serve as functional ingredients in cosmetics, eliminating the step of removing the extraction solvent in traditional processes, making it more economical and efficient, and providing favorable conditions for actual production and application. In addition, natural eutectic solvents have good solubility in both oil and aqueous phases, and can be used in both oil-phase and aqueous-phase cosmetics. For example, in the oil phase, they can reduce emulsification operations and also have a positive moisturizing effect.

[0055] According to the embodiments of this application, the myrtle fruit powder can be made from myrtle fruit from Paitan Town, Zengcheng District, Guangzhou. The extracted myrtle fruit extract contains a variety of active ingredients such as phenols, polysaccharides, flavonoids, volatile oils, and anthocyanins. Moreover, compared with conventional water extracts, the content of active ingredients in the extract using natural low co-solubility solvents is significantly increased.

[0056] In some embodiments, the hydrogen bond donor is selected from one or more of urea and carbohydrate-derived polyols or carboxylic acids. These hydrogen bond donors, with their interconnected hydrogen atoms, can form intermolecular hydrogen bonds, which can promote the dissolution and miscibility of myrtle fruit powder with natural eutectic solvents.

[0057] In some embodiments, the hydrogen bond acceptor is selected from one or more of carboxylates, quaternary ammonium salts, quaternary phosphonium salts, metal chlorides or sugar compounds, and organic alcohols.

[0058] Whether organic alcohols and carbohydrate-derived polyols act as hydrogen bond acceptors or hydrogen bond donors in natural eutectic solvents is not absolute; organic alcohols and carbohydrate-derived polyols can play different roles depending on the substances they are mixed with.

[0059] In some embodiments, the carbohydrate-derived polyol or carboxylic acid is selected from lactic acid, DL-malic acid, citric acid, formic acid, acetic acid, oxalic acid, malonic acid, succinic acid, adipic acid, capric acid, azelaic acid, benzoic acid, phenylacetic acid, 3-phenylpropionic acid, levulinic acid, glycerol, 1,3-propanediol, xylitol, D-isosorbitol, D-sorbitol, or combinations thereof.

[0060] According to embodiments of this application, the yield of myrtle fruit extract can be increased when the natural low-cosolvent contains formic acid, and the polyphenol content of the myrtle fruit extract can be increased when the natural low-cosolvent contains lactic acid. The aforementioned organic alcohols are selected from ethylene glycol, glycerol, 1,2-butanediol, or combinations thereof.

[0061] In some embodiments, the hydrogen bond acceptor is selected from one or a combination of several of sodium acetate, choline chloride, betaine, L-carnitine, and zinc chloride.

[0062] According to the embodiments of this application, the hydrogen bond acceptor can form intermolecular hydrogen bonds with the hydrogen bond donor, which can promote the dissolution of myrtle fruit powder in natural eutectic solvents.

[0063] In some embodiments, the natural low cosolvent is selected from sodium acetate, choline chloride, betaine, L-carnitine, zinc chloride, or combinations thereof. The aforementioned sodium acetate, etc., in the natural low cosolvent may subsequently exist in the myrtle fruit extract, and have positive antioxidant and antibacterial effects.

[0064] In some embodiments, the natural eutectic solvent comprises an organic salt.

[0065] According to the embodiments of this application, when the natural solvent contains organic salts, it has a positive effect on improving the solubility of active ingredients; the phenolic and anthocyanin substances in myrtle fruit have a high yield in natural eutectic solvents such as organic acids and organic alcohols; when the natural eutectic solvent contains sugar compounds, as the natural eutectic solvent is diluted with water, the interaction between molecules gradually decreases, and the interaction between molecules in the natural eutectic solvent containing sugar compounds decreases more slowly, which can improve the stability of the entire extraction solution.

[0066] According to the embodiments of this application, the phenolic and anthocyanin substances in myrtle fruit have high solubility in natural eutectic solvents such as organic salts. Since the myrtle fruit extract is a liquid mixture, the phenolic and anthocyanin substances in the myrtle powder can be retained to the greatest extent in the liquid mixture, which improves the yield. Moreover, the components of the natural eutectic solvent are non-toxic, making it very suitable as a raw material for cosmetics.

[0067] In some embodiments, the natural eutectic solvent further comprises water. When the natural eutectic solvent also comprises water, the solubility of myrtle fruit powder can be improved.

[0068] In some embodiments, the natural eutectic solvent contains 24%-26% water based on the total volume of the natural eutectic solvent. Therefore, the natural eutectic solvent can be a solution containing a certain amount of water, which can effectively improve the solubility of each component.

[0069] In some embodiments, the natural eutectic solvent also contains nonpolar amino acid compounds, such as proline, glycine, and alanine. The inventors unexpectedly discovered that when the natural eutectic solvent also contains the aforementioned nonpolar amino acid compounds, the yield of the active ingredient can be increased, and it also has a positive effect on repairing the skin barrier.

[0070] In some embodiments, the natural eutectic solvent is a mixture of sodium acetate and lactic acid. Surprisingly, the myrtle fruit extract prepared with the natural eutectic solvent being a mixture of sodium acetate and lactic acid exhibits the best antioxidant properties.

[0071] According to the embodiments of this application, lactic acid acts as a hydrogen bond donor, and sodium acetate acts as a hydrogen bond acceptor. Both exhibit a strong affinity for organic substances in myrtle powder, particularly tannins, ketones, phenols, and anthraquinones. This allows for the extraction of effective components such as carotene, myrtle amino acids, and myrtle tannins from the myrtle fruit plant. Furthermore, the mixture of sodium acetate and lactic acid is highly stable and exhibits high selectivity for tannin compounds in myrtle fruit, forming strong hydrogen bonds with them, thereby enabling the targeted extraction of effective tannin substances from myrtle fruit.

[0072] In some embodiments, the molar ratio of hydrogen bond donor to hydrogen bond acceptor is 1:(1-30), optionally 1:5.

[0073] According to embodiments of this application, the natural eutectic solvent, composed of hydrogen bond donors and hydrogen bond acceptors, exhibits an Overhauser nuclear effect in its nuclear magnetic resonance (NMR) image, forming a compound network through numerous hydrogen bonds. When the natural eutectic solvent is diluted, intermolecular interactions can be observed. When the molar ratio of hydrogen bond donors to hydrogen bond acceptors is 1:(1-30), the natural eutectic solvent not only possesses a stable compound network structure, improving the stability of active substances in myrtle fruit powder, but also effectively ensuring the solubility of the myrtle fruit powder. When the molar ratio of hydrogen bond donors to hydrogen bond acceptors is 1:5, the stability of phenols and anthocyanins is relatively high, allowing for appropriate ultrasonic and filtration treatments to prevent reactions with air and reduction of their effective content.

[0074] For example, the molar ratio of hydrogen bond acceptor to hydrogen bond donor can be independently selected from 1:1, 1:1.5, 1:20, 1:2, 1:5; the molar ratio of hydrogen bond acceptor to hydrogen bond donor can be independently selected from 1:7, 1:10, 1:15, 1:18, 1:20.

[0075] In some embodiments, the preparation method of a natural eutectic solvent includes: mixing a hydrogen bond donor and a hydrogen bond acceptor at a temperature of 70°C ± 5°C to obtain a natural eutectic solvent.

[0076] According to the embodiments of this application, mixing hydrogen bond acceptors and hydrogen bond donors in a certain molar ratio and heating and stirring at 70℃±5℃ until a homogeneous liquid is formed can improve the solubility of hydrogen bond acceptors and hydrogen bond donors, reduce the heating temperature when dissolving myrtle powder, and obtain a high-purity eutectic solvent without purification. Eutectic solvents have advantages such as a wide electrochemical window, good solubility and conductivity, low vapor pressure and good physicochemical stability, and can be used to prepare myrtle fruit extract.

[0077] For example, the above temperature can be the temperature of water bath heating, which can be independently selected from 65℃, 66℃, 67℃, 68℃, 69℃, 70℃, 71℃, 72℃, 73℃, 74℃, and 75℃.

[0078] In some embodiments, the preparation method of a natural eutectic solvent includes: mixing a hydrogen bond donor and a hydrogen bond acceptor at a temperature of 70°C ± 5°C, and diluting with water to obtain a natural eutectic solvent.

[0079] According to the embodiments of this application, natural eutectic solvents have advantages such as simple preparation process, low cost, no toxic or harmful solvents, and recyclability.

[0080] In some embodiments, in step S1, the ratio of myrtle fruit powder to natural eutectic solvent is 1:(20-25) g / mL. By controlling the solid-liquid ratio of myrtle fruit powder to natural eutectic solvent, the content of effective active components in the myrtle fruit extract can be maximized while ensuring the solubility of the myrtle fruit powder, and the myrtle fruit powder can be fully dissolved in the natural eutectic solvent.

[0081] For example, the solid-liquid ratio of myrtle fruit powder to a natural eutectic solvent can be independently selected as 1:20 g / mL, 1:21 g / mL, 1:22 g / mL, 1:23 g / mL, 1:24 g / mL, or 1:25 g / mL.

[0082] In some embodiments, step S1 includes heating under water bath conditions. Water bath heating allows for stable heating and dissolution of the myrtle fruit powder and the natural eutectic solvent. Since the target heating temperature is not high, water bath heating is sufficient.

[0083] In some embodiments, in step S1, the heating temperature is 45-55°C, optionally 50°C. Heating within this temperature range promotes the dissolution of the myrtle fruit powder without damaging its active components, thus improving dissolution efficiency.

[0084] In some embodiments, in step S2, the ultrasonic treatment includes applying ultrasonic waves with a power of 600W-700W to the mixture for a duration of 25min ± 1min. This can promote the dissolution of myrtle fruit powder in natural eutectic solvents while avoiding solution splashing, reducing the yield of effective active substances in the myrtle fruit powder, reducing energy consumption, and improving efficiency.

[0085] In some embodiments, step S3 includes:

[0086] S310. Filter the ultrasonically treated mixture;

[0087] S320. Soak the filtered residue obtained by filtration in the first solvent.

[0088] S330. Wash the soaked filter residue with a second solvent, and then filter it;

[0089] S340. Collect the filtrate obtained in the above steps and combine them, then concentrate to obtain myrtle fruit extract.

[0090] In some embodiments, the first solvent may be the aforementioned natural organic low-cosolvent or water, or a mixture of both.

[0091] In some embodiments, the filter residue can be soaked in water for 4-6 hours in S320.

[0092] In some embodiments, the second solvent may be the aforementioned natural organic low-cosolvent or water, or a mixture of both.

[0093] According to embodiments of this application, soaking the filter residue obtained after filtration in a first solvent can further dissolve the effective active ingredients in the filter residue, improving the utilization efficiency of the myrtle powder. Washing the soaked filter residue with a second solvent can fully recover the effective active ingredients in the filter residue. Furthermore, the filter residue obtained in the above steps can be spray-dried and used as fertilizer.

[0094] In some embodiments, step S3 further includes repeating steps S320 and S330 at least once. This can improve the utilization rate of myrtle powder and increase the yield of the effective active ingredient.

[0095] According to the embodiments of this application, the preparation method of the above-mentioned myrtle extract is simple in process, short in time, low in equipment requirements, and can be well compatible with existing processes, and has great potential for large-scale application.

[0096] Myrtle extract

[0097] The second aspect of this application provides a myrtle extract, obtained by the preparation method of the first aspect.

[0098] The myrtle extract provided in this application has high levels of effective active components, such as tannins, ketones, phenols, and anthraquinones, which have antibacterial and antioxidant effects and can be applied in the fields of cosmetics or medical aesthetics and other health-related fields.

[0099] Example

[0100] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on weight, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0101] Example 1

[0102] This application provides a method for preparing myrtle extract, comprising:

[0103] S1. Under water bath heating to 55°C, 2.2L of a mixture of natural eutectic solvent and deionized water and 100g of Guangzhou Zengcheng myrtle fruit powder (80 mesh) were mixed and the water bath conditions were maintained for 1.5 hours to obtain mixture 1.

[0104] S2. Mixture 1 is subjected to ultrasonic treatment. The ultrasonic extractor used during ultrasonic treatment has a power of 660W and an extraction time of 15 minutes to obtain mixture 2.

[0105] S3. Filter mixture 2, take the filtrate, soak the filtrate in water for 5 hours, wash the filtrate with water 3 times, then filter and concentrate the filtrate.

[0106] The natural eutectic solvent is sodium acetate and lactic acid, which are prepared by mixing sodium acetate and lactic acid at a molar ratio of 1:5 at 70°C.

[0107] Example 2

[0108] This application provides a method for preparing myrtle extract, comprising:

[0109] S1. Under water bath heating to 55°C, 2.2L of a mixture of natural eutectic solvent and deionized water and 100g of Guangzhou Zengcheng myrtle fruit powder (80 mesh) were mixed and the water bath conditions were maintained for 1.5 hours to obtain mixture 1.

[0110] S2. Mixture 1 is subjected to ultrasonic treatment. The ultrasonic extractor used during ultrasonic treatment has a power of 660W and an extraction time of 15 minutes, resulting in mixture 2.

[0111] S3. Filter mixture 2, take the filtrate, soak the filtrate in water for 5 hours, wash the filtrate with water 3 times, then filter and concentrate the filtrate.

[0112] The natural eutectic solvent is sodium acetate, lactic acid, and proline, which are prepared by mixing sodium acetate, lactic acid, and proline at a molar ratio of 1:5:1 at 70°C.

[0113] Example 3

[0114] This application provides a method for preparing myrtle extract, comprising:

[0115] S1. Under water bath heating to 55°C, 2.2L of a mixture of natural eutectic solvent and deionized water and 100g of Guangzhou Zengcheng myrtle fruit powder (80 mesh) were mixed and the water bath conditions were maintained for 1.5 hours to obtain mixture 1.

[0116] S2. Mixture 1 is subjected to ultrasonic treatment. The ultrasonic extractor used during ultrasonic treatment has a power of 660W and an extraction time of 15 minutes, resulting in mixture 2.

[0117] S3. Filter mixture 2, take the filtrate, soak the filtrate in water for 5 hours, wash the filtrate with water 3 times, then filter and concentrate the filtrate.

[0118] The natural eutectic solvent is citric acid and fructose, which are mixed at 70°C with fructose and citric acid in a molar ratio of 1:5.

[0119] Example 4

[0120] This application provides a method for preparing myrtle extract, comprising:

[0121] S1. Under water bath heating to 55°C, 2.2L of a mixture of natural eutectic solvent and deionized water and 100g of Guangzhou Zengcheng myrtle fruit powder (80 mesh) were mixed and the water bath conditions were maintained for 1.5 hours to obtain mixture 1.

[0122] S2. Mixture 1 is subjected to ultrasonic treatment. The ultrasonic extractor used during ultrasonic treatment has a power of 660W and an extraction time of 15 minutes, resulting in mixture 2.

[0123] S3. Filter mixture 2, take the filtrate, soak the filtrate in water for 5 hours, wash the filtrate with water 3 times, then filter and concentrate the filtrate.

[0124] The natural eutectic solvent is citric acid and ethylene glycol, which are prepared by mixing ethylene glycol and citric acid at a molar ratio of 1:5 at 70°C.

[0125] Example 5

[0126] This application provides a method for preparing myrtle extract, comprising:

[0127] S1. Under water bath heating to 55°C, 2.2L of a mixture of natural eutectic solvent and deionized water and 100g of Guangzhou Zengcheng myrtle fruit powder (80 mesh) were mixed and the water bath conditions were maintained for 1.5 hours to obtain mixture 1.

[0128] S2. Mixture 1 is subjected to ultrasonic treatment. The ultrasonic extractor used during ultrasonic treatment has a power of 660W and an extraction time of 15 minutes, resulting in mixture 2.

[0129] S3. Filter mixture 2, take the filtrate, soak the filtrate in water for 5 hours, wash the filtrate with water 3 times, then filter and concentrate the filtrate.

[0130] The natural eutectic solvent is choline chloride and DL-malic acid, which are prepared by mixing choline chloride and DL-malic acid at a molar ratio of 1:5 at 70°C.

[0131] Example 6

[0132] This application provides a method for preparing myrtle extract, comprising:

[0133] S1. Under water bath heating to 55°C, 2.2L of a mixture of natural eutectic solvent and deionized water and 100g of Guangzhou Zengcheng myrtle fruit powder (80 mesh) were mixed and the water bath conditions were maintained for 1.5 hours to obtain mixture 1.

[0134] S2. Mixture 1 is subjected to ultrasonic treatment. The ultrasonic extractor used during ultrasonic treatment has a power of 660W and an extraction time of 15 minutes, resulting in mixture 2.

[0135] S3. Filter mixture 2, take the filtrate, soak the filtrate in water for 5 hours, wash the filtrate with water 3 times, then filter and concentrate the filtrate.

[0136] The natural eutectic solvent is sodium acetate and lactic acid, which are prepared by mixing sodium acetate and lactic acid at a molar ratio of 1:1 at 70°C.

[0137] Example 7

[0138] This application provides a method for preparing myrtle extract, comprising:

[0139] S1. Under water bath heating to 55°C, 2.2L of a mixture of natural eutectic solvent and deionized water and 100g of Guangzhou Zengcheng myrtle fruit powder (80 mesh) were mixed and the water bath conditions were maintained for 1.5 hours to obtain mixture 1.

[0140] S2. Mixture 1 is subjected to ultrasonic treatment. The ultrasonic extractor used during ultrasonic treatment has a power of 660W and an extraction time of 15 minutes, resulting in mixture 2.

[0141] S3. Filter mixture 2, take the filtrate, soak the filtrate in water for 5 hours, wash the filtrate with water 3 times, then filter and concentrate the filtrate.

[0142] The natural eutectic solvent is sodium acetate and lactic acid, which are prepared by mixing sodium acetate and lactic acid at a molar ratio of 1:30 at 70°C.

[0143] Example 8

[0144] This application provides a method for preparing myrtle extract, comprising:

[0145] S1. Under water bath heating to 55°C, 2.2L of a mixture of natural eutectic solvent and deionized water and 100g of Guangzhou Zengcheng myrtle fruit powder (80 mesh) were mixed and the water bath conditions were maintained for 1.5 hours to obtain mixture 1.

[0146] S2. Mixture 1 is subjected to ultrasonic treatment. The ultrasonic extractor used during ultrasonic treatment has a power of 660W and an extraction time of 15 minutes, resulting in mixture 2.

[0147] S3. Filter mixture 2, take the filtrate, soak the filtrate in water for 5 hours, wash the filtrate with water 3 times, then filter and concentrate the filtrate.

[0148] The natural eutectic solvent is betaine and 1,3-propanediol, which are prepared by mixing betaine and 1,3-propanediol at a molar ratio of 1:10 at 70°C.

[0149] Example 9

[0150] This application provides a method for preparing myrtle extract, comprising:

[0151] S1. Under water bath heating to 55°C, 2.2L of a mixture of natural eutectic solvent and deionized water and 100g of Guangzhou Zengcheng myrtle fruit powder (80 mesh) were mixed and the water bath conditions were maintained for 1.5 hours to obtain mixture 1.

[0152] S2. Mixture 1 is subjected to ultrasonic treatment. The ultrasonic extractor used during ultrasonic treatment has a power of 660W and an extraction time of 15 minutes, resulting in mixture 2.

[0153] S3. Filter mixture 2, take the filtrate, soak the filtrate in water for 5 hours, wash the filtrate with water 3 times, then filter and concentrate the filtrate.

[0154] The natural eutectic solvent is carnitine and citric acid, which are mixed at 70°C in a molar ratio of 1:10.

[0155] Example 10

[0156] This application provides a method for preparing myrtle extract, comprising:

[0157] S1. Under water bath heating to 55°C, 2.2L of a mixture of natural eutectic solvent and deionized water and 100g of Guangzhou Zengcheng myrtle fruit powder (80 mesh) were mixed and the water bath conditions were maintained for 1.5 hours to obtain mixture 1.

[0158] S2. Mixture 1 is subjected to ultrasonic treatment. The ultrasonic extractor used during ultrasonic treatment has a power of 660W and an extraction time of 15 minutes, resulting in mixture 2.

[0159] S3. Filter mixture 2, take the filtrate, soak the filtrate in water for 5 hours, wash the filtrate with water 3 times, then filter and concentrate the filtrate.

[0160] The natural eutectic solvent is zinc chloride and urea, which are prepared by mixing zinc chloride and urea at a molar ratio of 1:3.5 at 70°C.

[0161] Example 11

[0162] This application provides a method for preparing myrtle extract, comprising:

[0163] S1. Under water bath heating to 55°C, 2.2L of a mixture of natural eutectic solvent and deionized water and 100g of Guangzhou Zengcheng myrtle fruit powder (80 mesh) were mixed and the water bath conditions were maintained for 1.5 hours to obtain mixture 1.

[0164] S2. Mixture 1 is subjected to ultrasonic treatment. The ultrasonic extractor used during ultrasonic treatment has a power of 660W and an extraction time of 15 minutes, resulting in mixture 2.

[0165] S3. Filter mixture 2, take the filtrate, soak the filtrate in water for 5 hours, wash the filtrate with water 3 times, then filter and concentrate the filtrate.

[0166] The natural eutectic solvent is choline chloride and xylitol, which are prepared by mixing choline chloride and xylitol at a molar ratio of 1:5 at 70°C.

[0167] Comparative Example 1

[0168] Compared with the implementation regulations, the comparative example uses deionized water instead of the natural low cosolvent in Example 1, while the remaining components and preparation process are the same as in the example.

[0169] Comparative Example 2

[0170] Compared with the implementation regulations, ethanol was used instead of the natural low co-solvent in the examples in the comparative example, while the remaining components and preparation process were the same as in the examples.

[0171] Comparative Example 3

[0172] Compared with the implementation regulations, the comparative example uses ethanol instead of the natural low-cosolvent in the examples, does not use ultrasonic extraction, and directly uses stirring extraction. The remaining components and preparation process are the same as in the examples.

[0173] Comparative Example 4

[0174] Compared with the implementing regulations, the comparative example uses sodium acetate and lactic acid as natural eutectic solvents. Sodium acetate and lactic acid are mixed at 70°C in a molar ratio of 1:31 to obtain the remaining components and the preparation process is the same as in the example.

[0175] Comparative Example 5

[0176] Compared with the implementation regulations, the comparative example uses sodium acetate and lactic acid as natural eutectic solvents. Sodium acetate and lactic acid are mixed at 70°C in a molar ratio of 2:1 to obtain the remaining components and the preparation process is the same as in the example.

[0177] Comparative Example 6

[0178] Compared with the implementation regulations, the comparative example used sodium acetate and lactic acid and proline as natural eutectic solvents. Sodium acetate, lactic acid and proline were mixed at 70°C with stirring in a molar ratio of 1:5:1. 1.9 L of the natural eutectic solvent was mixed with deionized water and 100 g of Guangzhou Zengcheng myrtle fruit powder (80 mesh). The mixture was kept in a water bath for 1.5 hours to obtain mixture 1. The remaining components and preparation process were the same as in the example.

[0179] Comparative Example 7

[0180] Compared with the implementation regulations, the comparative example used sodium acetate and lactic acid and proline as natural eutectic solvents. Sodium acetate, lactic acid and proline were mixed at 70°C with stirring in a molar ratio of 1:5:1. 2.6L of the natural eutectic solvent was mixed with deionized water and 100g of Guangzhou Zengcheng myrtle fruit powder (80 mesh), and the mixture was kept in a water bath for 1.5 hours to obtain mixture 1. The remaining components and preparation process were the same as in the example.

[0181] Test section

[0182] 1) Detection of total polyphenol content

[0183] The total polyphenol content in plant extracts and their products was determined using the Folin-Ciocalteu spectrophotometric method. Phenolic compounds reduce phosphotungstic acid under alkaline conditions to form a blue compound. Within a certain concentration range, the absorbance is directly proportional to the content of the phenolic compound, conforming to the Lambert-Beer Law.

[0184] 1. Reagents and Materials

[0185] 1.1 Reagents

[0186] 1.1.1 Anhydrous ethanol: analytical grade.

[0187] 1.1.2 Folin-Ciocalteu reagent: analytical grade.

[0188] 1.1.3 Sodium carbonate: analytical grade.

[0189] 1.1.4 The water is Grade I water as specified in GB / T 6682.

[0190] 1.2 Reagent Preparation

[0191] 1.2.1 Sodium carbonate solution (15%): Accurately weigh 15g of anhydrous sodium carbonate, dissolve it in water and bring the volume to 100mL.

[0192] 1.2.2 Ethanol solution (60%): Measure 600 mL of anhydrous ethanol, dissolve it in water and make up to 1000 mL.

[0193] 1.3 Standard Products

[0194] Gallic acid (C7H6O5, CAS No.: 149-91-7), purity ≥99.0%.

[0195] 1.4 Preparation of Gallic Acid Standard Stock Solution

[0196] Accurately weigh 20 mg (accurate to 0.1 mg) of gallic acid standard, dissolve it in distilled water, and bring the volume to 100 mL. The gallic acid content in this solution is 200 mg / L. Store in a refrigerator at 4°C, protected from light.

[0197] 2. Instruments and Equipment

[0198] 2.1 UV-Vis spectrophotometer: equipped with a 1cm cuvette.

[0199] 2.2 Analytical balance: sensitivity 0.1 mg.

[0200] 2.3 Electric thermostatic water bath: 0℃~100℃.

[0201] 3. Analysis Steps

[0202] 3.1 Instrument Conditions

[0203] 3.1.1 Measurement wavelength: 778nm.

[0204] 3.1.2 Cuvette: 1cm.

[0205] 3.2 Construction of Standard Curve

[0206] Accurately pipette 0.0, 0.2, 0.4, 0.6, 1.0, and 1.5 mL of gallic acid standard stock solution (4.4) into 10 mL volumetric flasks, and dilute to volume with 60% ethanol solution (4.2.2) to obtain gallic acid working solutions. Then, transfer 1.0 mL of the gallic acid working solution into a 10 mL colorimetric tube, add 2.5 mL of Folin-Ciocalteu reagent (4.1.2), shake well, add 2.5 mL of 15% Na₂CO₃ solution (4.2.1), and dilute to the mark with water, shaking well. Incubate in a 40℃ water bath for 60 min, and allow to cool for 20 min. Prepare a standard series with concentrations of 0 mg / L, 4 mg / L, 8 mg / L, 12 mg / L, 20 mg / L, and 30 mg / L, and measure their absorbance values. Plot a standard curve with concentration on the x-axis and absorbance on the y-axis.

[0207] 3.3 Determination of Sample Solution

[0208] Pipette 1.0 mL of the filtrate into a 10 mL colorimetric tube, add 2.5 mL of Folin-Ciocalteu reagent (4.1.2), shake well, add 2.5 mL of 15% Na₂CO₃ solution (4.2.1), and dilute to the mark with water. Shake well. Incubate in a water bath at 40 °C for 60 min, allow to cool for 20 min, and measure the absorbance. Calculate the concentration of total polyphenols in the test solution based on the standard curve.

[0209] 4.0 Presentation of Analysis Results

[0210] The total polyphenol content is calculated according to formula (1):

[0211] X = c × 10 × n (1)

[0212] In the formula: X — the total polyphenol content in the sample, in milligrams per liter (mg / L);

[0213] c——The total polyphenol content in the test solution calculated from the standard curve, in milligrams per liter (mg / L);

[0214] 10 — Filtrate dilution factor;

[0215] n—sample dilution factor. Results should be rounded to one decimal place.

[0216] 5.0 Precision Calculation:

[0217] The absolute difference between two independent measurements obtained under repeatability conditions shall not exceed 10% of the arithmetic mean.

[0218] 2) Detection of total flavonoid content

[0219] Flavonoids (calculated as rutin) form chelates with aluminum salts under weakly alkaline conditions. The chelates develop color upon the addition of sodium hydroxide solution, and the absorbance is measured at 506 nm. Within a certain concentration range, the absorbance of the chelate is directly proportional to the flavonoid content, and quantification is achieved by comparison with a standard series.

[0220] 2.1 Reagents and Materials

[0221] Unless otherwise specified, only reagents confirmed to be of analytical grade and Grade I water as specified in GB / T 6682 shall be used in the analysis.

[0222] 2.2 Reagents

[0223] 2.2.1 Anhydrous ethanol (CH3CH2OH) CAS 6417-5;

[0224] 2.2.2 Sodium nitrite (NaNO2, CAS 768200).

[0225] 2.2.3 Aluminum nitrate [Al(NO3)·9H2O, CAS No.: 7X84221]

[0226] 2.2.4 Sodium hydroxide (NaOH, CAS No.: 1310-73-29)

[0227] 2.3 Solution Preparation

[0228] 2.3.1 Ethanol solution (7+3): Add 70 mL of anhydrous ethanol to 30 mL of water, stir well, and set aside.

[0229] 2.3.2 Ethanol solution (3+7): Take 30 mL of anhydrous ethanol and add it to 70 mL of water. Stir well and set aside.

[0230] 2.3.3 Sodium nitrite solution (50g / L): Accurately weigh 5.00g of sodium nitrite into a beaker, add an appropriate amount of water to dissolve it, transfer it to a 100mL volumetric flask, dilute to the mark with water, shake well, and set aside.

[0231] 2.3.4 Aluminum nitrate solution (100g / L): Accurately weigh 17.60g of aluminum nitrate into a beaker, add an appropriate amount of water to dissolve it, transfer it to a 100mL volumetric flask, dilute to the mark with water, shake well, and set aside.

[0232] 2.3.5 Sodium hydroxide solution (40g / L): Accurately weigh 20.00g of sodium hydroxide into a beaker, add an appropriate amount of water to dissolve it, transfer it to a 500mL volumetric flask, dilute to the mark with water, shake well, and set aside.

[0233] 2.4 Standard Products

[0234] Rutin standard (CHO1, CAS No.: 153-18-4): purity ≥98%.

[0235] 2.5 Preparation of Standard Solutions

[0236] Rutin standard stock solution (1.00 mg / mL): Accurately weigh 0.05 g of rutin standard (accurate to [value missing]).

[0237] 0.0001 g), dissolved in ethanol solution and diluted to a 50.0 mL amber volumetric flask, shaken well, to prepare the solution.

[0238] 1.00 mg / mL standard stock solution.

[0239] 2.6 Instruments and Equipment

[0240] 2.6.1 Visible spectrophotometer.

[0241] 2.6.2 Analytical balance: sensitivity 0.0001g and 0.01g.

[0242] 2.6.3 Water bath oscillator: The oscillation frequency shall not be less than 240 r / min.

[0243] 2.6.4 Centrifuge: The rotation speed shall not be less than 4000 r / min.

[0244] 2.6.5 Vortex mixer.

[0245] 2.6.6 High-speed pulverizer: rotation speed not less than 10000 r / min.

[0246] 2.6.7 High-speed blender: speed not less than 10000r / min.

[0247] 2.6.8 Cuvette: Glass.

[0248] 2.7 Analysis Steps

[0249] 2.7.1 Plotting the Standard Curve

[0250] Pipettes of 0 mL, 0.05 mL, 0.10 mL, 0.20 mL, 0.30 mL, 0.40 mL, 0.50 mL, and 0.60 mL of rutin standard stock solution (1.00 mg / mL) into 10.0 mL colorimetric tubes, respectively. Add 4.00 mL of anhydrous ethanol, shake well, then add 0.5 mL of sodium nitrite solution, shake well; let stand for 5 min, then add 0.5 mL of aluminum nitrate solution, shake well; let stand for 5 min, then add 2.0 mL of sodium hydroxide solution, shake well. Finally, dilute to volume with ethanol solution to obtain concentrations of 0 mg / L, 5.0 mg / L, and...

[0251] A series of standard working solutions with concentrations of 10.0 mg / L, 20.0 mg / L, 30.0 mg / L, 40.0 mg / L, 50.0 mg / L, and 60.0 mg / L were used, and their absorbance was measured at a wavelength of 508 nm. A standard curve was plotted with the rutin mass concentration p (mg / L) on the x-axis and the corresponding absorbance value A on the y-axis, and the regression equation for the standard curve was obtained.

[0252] 2.7.2 Measurement

[0253] Add 0.5 mL of sodium nitrite solution to the test solution and shake well; let stand for 5 min, then add 0.5 mL of aluminum nitrate solution and shake well; let stand for 5 min, then add 2.0 mL of sodium hydroxide solution and shake well. Finally, dilute to 10.00 mL with ethanol solution and shake well. Measure the absorbance of the sample at a wavelength of 508 nm to determine the rutin content in the test solution from the standard curve. Perform a blank test simultaneously.

[0254] 2.7.3 Blank Test

[0255] Take 1.00 mL of ethanol solution into a 10.0 mL colorimetric tube, add 4.00 mL of anhydrous ethanol, shake well, and follow the same steps as in 2.7.2.

[0256] 2.8 Calculation of Results

[0257] The total flavonoid content in the sample is expressed as the mass fraction w of rutin and calculated according to formula (1).

[0258]

[0259] In the formula:

[0260] w—The total flavonoid content in the sample, expressed in milligrams per gram (mg / g);

[0261] p—The mass concentration of total flavonoids in the test solution of the sample, obtained from the standard curve, in milligrams per liter (mg / L);

[0262] p o —Find the mass concentration of total flavonoids in the blank test solution from the standard curve, in milligrams per liter (mg / L);

[0263] V1 — The numerical value of the volume of extraction solution added to and brought to a final volume in the sample, in milliliters (mL);

[0264] V3 — The final volume of the sample, expressed in millikat (mL5);

[0265] m — the numerical value of the sample mass, in grams.

[0266] V2 – The numerical value of the extract fraction, in milliliters (mL), obtained through calculation.

[0267] 2.9 Precision

[0268] Under repeatability conditions, the absolute difference between two independent test results should not exceed 10% of the arithmetic mean. Results after testing are shown in Table 1 and... Figure 1 The results are shown.

[0269] Table 1: Total polyphenol content of samples

[0270]

[0271]

[0272] From Table 1, Figure 1It can be seen that, in the comparative examples, the total polyphenol content of the myrtle fruit extract obtained by water extraction in Comparative Example 1 is higher due to the better water solubility of polyphenols. The data from Comparative Examples 2 and 3 show that the use of ultrasound in the ethanol extraction process helps to improve the yield of the target compound. The polyphenol content of the myrtle fruit extract obtained by the example using natural eutectic solvent extraction is higher than that of the myrtle fruit extracts obtained by comparative examples 2 and 3 using organic solvent ethanol extraction. The total polyphenol and total flavonoid content of the myrtle fruit extract obtained by the example using natural eutectic solvent hydrogen bond acceptor: hydrogen bond donor = 1:(1-30) is higher than that of the myrtle fruit extract obtained by comparative example 4 using natural eutectic solvent hydrogen bond acceptor: hydrogen bond donor = 1:31 and comparative example 5 using natural eutectic solvent hydrogen bond acceptor: hydrogen bond donor = 2:1. The total polyphenol and total flavonoid content of the myrtle fruit extract obtained by the example using a material-to-liquid ratio of 1:(20-25) g / mL is higher than that of the myrtle fruit extract obtained by comparative example 6 using a material-to-liquid ratio of 1:19 g / mL and comparative example 7 using a material-to-liquid ratio of 1:26 g / mL. In Example 2, the total polyphenols and total flavonoids were obtained by extraction using a natural eutectic solvent of sodium acetate: lactic acid: proline. The addition of the nonpolar amino acid proline helps to enhance the stability of hydrogen bonds in the natural eutectic solvent, thereby increasing the extraction rate of active ingredients.

[0273] Meanwhile, from Table 1 and Figure 1 Overall, the total flavonoid content of the myrtle fruit extract obtained using a natural eutectic solvent as the extraction agent was significantly higher than that obtained by traditional water extraction and also higher than that obtained by extraction with organic solvent ethanol without ultrasonication. Data from Comparative Examples 2 and 3 show that using ultrasound in the extraction process can improve the yield of total flavonoids.

[0274] From the data on total polyphenols and total flavonoids in the above examples and comparative examples, it can be concluded that it is feasible to use natural eutectic solvents as extractants to extract myrtle fruit. Moreover, due to its natural, green, and environmentally friendly advantages, sodium acetate-lactic acid-proline can completely replace traditional water extraction and organic solvent ethanol extraction as an extractant.

[0275] 2) Antioxidant efficacy test of myrtle fruit extract (free radical scavenging rate test)

[0276] 1. Preparation of DPPH solution

[0277] Dissolve 1 mg of DPPH (1,1-diphenyl-2-trinitrophenylhydrazine) solid in 24 mL of anhydrous ethanol, sonicate for 5 min, shake thoroughly to ensure uniformity of the contents, store away from light, and use within 5 hours.

[0278] Take 1 mL of the prepared DPPH solution and dilute it with 0.5 mL of anhydrous ethanol until the absorbance is between 0.6 and 1.0. If the absorbance is greater than 1.0, continue adding anhydrous ethanol; if the absorbance is less than 0.6, add more DPPH solid or DPPH solution.

[0279] 1.2 Preparation of sample solution

[0280] The myrtle fruit extracts prepared in Examples 1-4 and Comparative Examples 1-2 were taken as samples, dissolved in ethanol, and prepared to a concentration of 1 mg / mL.

[0281] The antioxidant effect of a sample is measured by the DPPH scavenging rate; the higher the DPPH scavenging rate, the better the antioxidant effect. The formula for calculating the DPPH scavenging rate is: DPPH scavenging rate (%) = 100% * (A0 - A) / A0; where A0 is the absorbance value without the sample, and A is the absorbance value after adding the sample. To determine the A0 value: Take 1.0 mL of DPPH solution into a cuvette, add 0.5 mL of ethanol, dilute and mix, and measure the A0 value. This A0 value should be between 0.8 and 1.0. To determine the A value: Take 400 μL of ethanol into a cuvette, add 100 μL of sample, then add 1.0 mL of DPPH solution, and measure the A value.

[0282] The results were obtained from the tests, as shown in Table 2 and... Figure 2 The results are shown.

[0283] Table 2: Statistical analysis of DPPH scavenging rate of samples

[0284]

[0285]

[0286] From Table 2 and Figure 2 It can be seen that the DPPH scavenging rate of the myrtle fruit extract prepared in the embodiments of the present invention is significantly higher than that of the myrtle fruit extract prepared in the comparative examples. The myrtle fruit extract prepared by conventional water extraction in Comparative Example 1 contains a large amount of polyphenols, giving it the effect of scavenging DPPH free radicals. However, the myrtle fruit extract prepared using the organic solvent ethanol in Comparative Example 2 contains a considerable amount of polyphenols and flavonoids. The synergistic effect of the two makes the DPPH free radical scavenging effect of Comparative Example 2 stronger than that of Comparative Example 1. A comparison between Comparative Example 3 and Comparative Example 2 shows that the ultrasonic extraction process can extract more and higher-activity active substances. In the DPPH scavenging experiment, the natural eutectic solvent can completely replace the organic solvent ethanol to obtain a myrtle fruit extract with high DPPH scavenging activity.

[0287] 3) Antibacterial effect test

[0288] Test plates were prepared for *Escherichia coli*, *Salmonella*, *Propionibacterium acnes*, Gram-positive bacteria, and *Staphylococcus aureus* as test strains, with each strain replicated 5 times. In the test plates, squares (0.5cm × 0.5cm) were cut using a sterile knife. The middle culture medium was removed with tweezers to form squares. An equal volume of 10 μg / mL of the myrtle fruit extract prepared according to the present invention and Comparative Examples 1 and 2 was added to each square. The bacteria were incubated at 37°C for 24 hours. The blank control group used deionized water. The size of the inhibition zone was then tested, and the results are shown in Table 2 (in Table 3, "-" indicates no inhibitory effect; an inhibition zone smaller than 7 mm is considered to have no inhibitory effect).

[0289] Table 3: Statistics on antibacterial effect (the size of the antibacterial zone is in mm)

[0290]

[0291] As can be seen from Table 3, the antibacterial effect of the myrtle fruit extract prepared in the embodiments of the present invention is significantly better than that of the myrtle fruit extract prepared in the comparative example. Furthermore, the results from the embodiments show that the myrtle fruit extract prepared using the NADESs sodium acetate:lactic acid:proline system in Example 2 has a significant antibacterial effect on acne, and its extraction effect on the effective components of myrtle fruit is better.

[0292] 4) HPLC detection

[0293] A Thermo Hypersil BDS C18 column (4.6 mm × 250 mm, 5 μm) was used. The mobile phase system, gradient elution design, and analytical parameters were evaluated based on the absence of peak tailing, baseline drift, and resolution in the chromatogram. Mobile phase conditions: Phase A was acetonitrile, and Phase B was 0.1% phosphoric acid aqueous solution. Column oven temperature: 30℃; detection wavelength: 280 nm; detection time: 95 min; injection volume: 10 μL. Mobile phase: 0-5 min, 5% A; 5-25 min, 12% A; 25-45 min, 60% A; 45-75 min, 90% A; 75-80 min, 5% A. Flow rate: 1.0 mL / min.

[0294] The high-performance liquid chromatograms of Example 2 and Comparative Examples 1 and 2 are shown below. Figure 3 and Figure 4 , Figure 5As shown in the figure, peak 2 is gallic acid, peak 3 is catechin, peak 4 is ellagic acid, and peak 5 is another substance. From the above HPLC chromatogram, it can be seen that water extraction at 55℃ (Comparative Example 1) can only extract water-soluble phenolic acids, such as gallic acid. Ethanol extraction at 55℃ (Comparative Example 2) can extract a small amount of phenolic acids, including poorly water-soluble ellagic acid, leucine, and resveratrol. Under the natural eutectic solvent conditions of sodium acetate-lactic acid-proline at 55℃, more water-soluble phenolic acids can be extracted, such as peaks 3 and 9, as shown in the HPLC chromatogram of Example 2, along with many other small peaks. This indicates that this extractant can extract more phenolic acids. It can also be seen that this extractant can extract more poorly water-soluble substances, as shown in peak 8 and other peaks. The HPLC chromatograms above show that Example 2, using a natural eutectic solvent, can extract a wider range of substances with greater polarity, which is consistent with the previous results of detecting the content of total polyphenols and total flavonoids.

[0295] Application Example 1

[0296] The myrtle fruit extract prepared in Example 1 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0297] Application Example 2

[0298] The myrtle extract prepared in Example 2 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0299] Application Example 3

[0300] The myrtle extract prepared in Example 3 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0301] Application Example 4

[0302] The myrtle extract prepared in Example 4 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0303] Application Example 5

[0304] The myrtle extract prepared in Example 5 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0305] Application Example 6

[0306] The myrtle extract prepared in Example 6 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0307] Application Example 7

[0308] The myrtle extract prepared in Example 7 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0309] Application Example 8

[0310] The myrtle extract prepared in Example 8 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0311] Application Example 9

[0312] The myrtle extract prepared in Example 9 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0313] Application Example 10

[0314] The myrtle extract prepared in Example 10 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0315] Application Example 11

[0316] The myrtle extract prepared in Example 11 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0317] Application Example 12

[0318] The myrtle extract prepared in Comparative Example 1 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0319] Application Example 13

[0320] The myrtle extract prepared in Comparative Example 2 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0321] Application Example 14

[0322] The myrtle extract prepared in Comparative Example 3 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0323] Application Example 15

[0324] The myrtle extract prepared in Comparative Example 4 was used in a soothing cosmetic product, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0325] Application Example 16

[0326] The myrtle extract prepared in Comparative Example 5 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0327] Application Example 17

[0328] The myrtle extract prepared in Comparative Example 6 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0329] Application Example 18

[0330] The myrtle extract prepared in Comparative Example 7 was used in a soothing cosmetic, comprising, by weight: 5 parts myrtle extract, 0.3 parts xanthan gum, 5 parts glycerin, and the remainder being water, with a pH of 6.0-7.0.

[0331] Soothing effect cosmetic performance testing

[0332] Sodium dodecyl sulfate (SLS) was prepared into a 2% aqueous solution. Eligible subjects were equilibrated in a constant temperature and humidity environment for 30 minutes before undergoing SLS patch stimulation. Each sample consisted of 8-15 subjects.

[0333] The specific steps are as follows: SLS aqueous solution is added to a filter paper disc, which is then placed inside a patch applicator and quickly applied to the hairless area of ​​the subject's inner forearm / lower leg. After 24 hours, the patch applicator is removed, and a professional researcher inquires about and examines the skin condition of the induced test site. The researcher should assess the minimum erythema response and exclude test areas with poor consistency (no erythema response, erythema response different from other test areas) to determine whether SLS stimulation was successful. Simultaneously, the a* value is measured using a skin erythema index meter, and the transepidermal water loss (TWEL) value is measured using a probe. Samples are then distributed to the subjects, and they are informed in detail of the usage instructions and precautions. Subjects use the product on each erythema response test area as instructed, continuously for 3 days. Skin erythema response areas are tested and recorded at 24, 48, and 72 hours after product use.

[0334] Get as Figures 6-9 As shown in the clinical data above, cosmetics prepared using myrtle fruit extract obtained through natural eutectic solvent extraction (Examples 1-11) exhibit better effects in soothing SLS irritation and reducing transdermal water loss than cosmetics prepared using myrtle fruit extract obtained through conventional water extraction and ultrasonic extraction with organic solvent ethanol (Examples 12, 13, and 14). Among these, cosmetics prepared using myrtle fruit extract obtained through sodium acetate-lactic acid-proline extraction (Example 2) show the best effect in soothing SLS irritation and reducing transdermal water loss, followed by cosmetics prepared using myrtle fruit extract obtained through sodium acetate-lactic acid extraction (Example 1), and then cosmetics prepared using myrtle fruit extract obtained through citric acid-ethylene glycol extraction (Example 4) show the third best effect in soothing SLS irritation.

[0335] The above clinical data leads to the conclusion that the extraction efficiency of natural eutectic solvents is superior to that of traditional extraction methods, and can completely replace traditional water extraction and organic solvent ethanol extraction. The optimal effect is achieved when the molar ratio of hydrogen bond acceptor to hydrogen bond donor is 1:(1-30) and the material ratio is 1:(20-25) g / ml.

[0336] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing a myrtle extract, characterized in that, include: S1. Under heating conditions, myrtle fruit powder is mixed with a natural eutectic solvent, wherein the ratio of the amount of myrtle fruit powder to the amount of the natural eutectic solvent is 1:(20-25) g / mL, wherein the natural eutectic solvent is sodium acetate, lactic acid and proline, and the molar ratio of sodium acetate, lactic acid and proline is 1:5:1; S2. Sonicate the mixture from step S1; S3. Filter the ultrasonically treated mixture to obtain the myrtle fruit extract from the filtrate.

2. The preparation method according to claim 1, characterized in that, The method for preparing the natural eutectic solvent includes mixing sodium acetate, lactic acid and proline at a temperature of 70℃±5℃ to obtain the natural eutectic solvent.

3. The preparation method according to claim 1, characterized in that, In step S1, the heating conditions include: heating in a water bath; and / or, In step S1, the heating temperature is 45-55℃.

4. The preparation method according to claim 3, characterized in that, In step S1, the heating temperature is 50°C.

5. The preparation method according to claim 1, characterized in that, In step S2, the ultrasonic treatment includes applying ultrasonic waves with a power of 600W-700W to the mixture for a duration of 25min±1min.

6. A myrtle extract with antibacterial and antioxidant properties, obtained by the preparation method according to any one of claims 1-5.

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