Application of deuterium-depleted water in extraction of polyphenol compounds in plants and extraction method of polyphenol compounds

Abstract

The invention belongs to the technical field of plant extraction, and particularly discloses application of deuterium-depleted water in extraction of polyphenol compounds in plants and an extraction method of the polyphenol compounds. The method comprises the following steps: selecting plant powder and an extraction solvent according to a solid-liquid ratio of 1: (10-50) ml / g, adding the plant powder and the extraction solvent into an extraction tank, uniformly mixing, extracting for 10-120 minutes under the conditions that the temperature is 120-220 DEG C and the pressure is 4-6 Mpa, and filtering and centrifuging an extracting solution to obtain an extract containing polyphenol compounds; wherein deuterium-depleted water with deuterium concentration less than 138 ppm is adopted as an extraction solvent. According to the method, deuterium-depleted water is applied to extraction of polyphenol compounds in plants for the first time, green extraction is achieved, and the extraction efficiency of the method is far better than that of existing reflux extraction, ultrasonic extraction and other methods.

Description

Technical Field

[0001] This invention belongs to the field of natural compound extraction technology, specifically relating to the application of deuterium-low water in the extraction of polyphenolic compounds from plants and its extraction method. Background Technology

[0002] Plant polyphenols are a class of compounds with multi-functional phenolic structures widely found in plants, and are important secondary metabolites in plants. Polyphenols are among the most abundant phytochemicals found in plants, primarily in the bark, roots, leaves, and fruits. More than 8,000 different polyphenolic compounds with varying structures are known, with hundreds isolated from edible plants, mostly from vegetables, fruits, nuts, tea, and traditional Chinese medicine. Based on their chemical structures, polyphenols can be divided into five categories: flavonoids, phenolic acids, lignans, stilbenes, and others, with phenolic acids and flavonoids accounting for the largest proportion (around 90%). As a large class of functional substances with significant biological activity, polyphenols are considered the seventh essential nutrient and are widely used in the production of functional health foods. Polyphenols possess strong antioxidant properties and also exhibit anti-tumor, anti-infective, liver-protective, immune-boosting, blood sugar-lowering, and cholesterol-lowering effects.

[0003] Flavonoids are an important class of natural organic compounds, secondary metabolites produced by plants through long-term natural selection. They are widely found in a variety of plants, not only in large quantities but also in complex and diverse structural types. Due to their unique chemical structures, flavonoids have many important physiological and biochemical effects on mammalian and other cell types, and are the active ingredients in many traditional Chinese medicines. Flavonoids are polyphenolic substances with a C6-C3-C6 structure. Based on the degree of oxidation of the central three-carbon chain, the position of the B-ring (2- or 3-position), and whether the three-carbon chain forms a ring, the main natural flavonoids can be classified into fifteen types: flavones, flavonols, flavonones, flavanonols, anthocyanidins, flavan-3,4-diols, xanthones, chalcones, and biflavonoids. Apigenin in Daphne genkwa and luteolin in Lonicera japonica belong to the flavonoid class; kaempferol and quercetin in Ginkgo biloba belong to the flavonol class. Glycyrrhizin in licorice and hesperidin in orange peel both belong to the dihydroflavonoid class; dihydroquercetin in Azalea and dihydromocarboxin in mulberry twigs both belong to the dihydroflavonol class. Pterostilbene in the Chinese medicinal herb Sophora flavescens is a derivative of dihydroisoflavones. Safflower glycoside in the Chinese medicinal herb Carthamus tinctorius belongs to the chalcone class. Thiuronyl sulfadiazine in Cosmos chrysanthemum belongs to the hesperidin class. Cyanide, delphinidin, and pelargonidin belong to the anthocyanin class. (+)catechin and (–)epicatechin belong to the flavanol class, hence they are also called catechins. In addition, some flavonoid compounds have very complex structures, including alkaloid flavonoids such as fimbriae and isoflavones. For example, ginkgol found in ginkgo leaves is a biflavonoid derivative bound by C / C bonds. Ophiopogon japonicus contains isoflavone A, a type of isoflavone. Kaelin, obtained from the seeds and fruits of *Cephalotaxus fortunei*, is a furanochrome. Fusarium oxysporum contains cinnamylase, a benzylchrome. Most natural flavonoids exist in glycoside form (i.e., flavonoid glycosides). It has been reported that adequate intake of flavonoids can reduce the incidence of diseases such as cancer, tumors, cardiovascular disease, lipid peroxidation, and osteoporosis.

[0004] Currently, common methods for extracting polyphenols from plants include reflux extraction, pressing extraction, ultrasound-assisted extraction, microwave-assisted extraction, and supercritical fluid extraction. Each method has its own specific advantages and applicable scenarios. Publication number CN119925981A discloses a fluid extraction method for extracting active ingredients from natural plants, using supercritical CO2 fluid for extraction to separate the active ingredients. The supercritical CO2 fluid extraction is performed at a temperature of 35℃, an extraction pressure of 20MPa, an extraction time of 6 hours, an extraction fluid flow rate of 10L / h, and an entrainer ethanol concentration of 100ml ethanol / 100g CO2. Application CN 119930417 A discloses a polyphenol compound, its preparation method, and its application. Using dried branches and leaves of *Daphne odora* as raw material, an aqueous ethanol solution with a volume concentration 8-15 times that of the raw material is added. The mixture is refluxed and extracted 2-4 times, each extraction lasting 2-4 hours. The extracts are combined, the solvent is recovered under reduced pressure, and the extract is concentrated to obtain the total extract. In these extraction methods, organic solvents such as ethanol are required during the extraction process, resulting in organic solvent residues in the extract. Furthermore, these extraction methods are time-consuming, leading to low extraction efficiency. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by using low-deuterium water as an extraction solvent to extract polyphenolic compounds from plants, thereby reducing organic solvent residues, shortening extraction time, and achieving green and efficient extraction and high-quality conversion.

[0006] This invention relates to the application of low-deuterium water as an extraction solvent in the extraction of polyphenolic compounds from plants. Low-deuterium water refers to water with a deuterium content lower than the standard for natural water. Ordinary water in nature has a deuterium content of 150 ppm, and water with a deuterium concentration below 150 ppm is considered low-deuterium water. Low-deuterium water has applications in medicine, cosmetics, and agriculture. After long-term research, the inventors have, for the first time, proposed using low-deuterium water with a deuterium concentration of less than 138 ppm as an extraction solvent for extracting polyphenolic compounds from plants such as traditional Chinese medicine, vegetables, and fruits. Because the deuterium concentration of water is less than 138 ppm, the surface tension of the water varies, resulting in molecular clusters of different sizes and numbers. The molecular clusters of low-deuterium water are more than 50% smaller than those of ordinary water, resulting in higher transdermal absorption capacity and more effectively promoting the penetration of various active ingredients through the cell barrier, thereby increasing the extraction rate of each active ingredient.

[0007] As a preferred option, low-deuterium water with a deuterium concentration of less than or equal to 100 ppm has a higher extraction rate, and with the extraction conditions remaining the same, the lower the deuterium concentration, the higher the extraction rate.

[0008] Furthermore, the extraction is performed at a pressure of 4-6 MPa and a temperature of 120-220℃ for 10-120 minutes. The extraction ratio is 1:10-50 ml / g.

[0009] Furthermore, this invention provides a method for extracting polyphenolic compounds from plants. The method involves selecting plant powder and extraction solvent at a material-to-liquid ratio of 1:10-50, adding them to an extraction tank, mixing them evenly, and extracting for 10-120 minutes at a temperature of 120-220℃ and a pressure of 4-6 MPa. The extract is then filtered, centrifuged, and concentrated to obtain an extract containing polyphenolic compounds. The extraction solvent is low-deuterium water with a deuterium concentration of less than 138 ppm. Preferably, the deuterium concentration of the low-deuterium water is less than or equal to 100 ppm.

[0010] Furthermore, the particle size of the plant powder is controlled at 60-100 mesh.

[0011] The plant powder includes powder made from the roots, stems, leaves, and fruits of plants; the plants include traditional Chinese medicine, tea, vegetables, and fruit trees, and the traditional Chinese medicine is selected from those rich in polyphenolic compounds, such as Polygonum cuspidatum, Houttuynia cordata, Citrus aurantium, Chrysanthemum indicum, Citrus medica, and Guava.

[0012] Furthermore, the centrifugation involves centrifuging the filtered extract at 4000 r / min for 5 min.

[0013] Furthermore, it also includes concentration, which involves evaporating the supernatant obtained by centrifugation under reduced pressure at a temperature of 60°C to concentrate it into a paste-like state.

[0014] The beneficial effects of this invention are:

[0015] (1) This invention is the first to discover that low-deuterium water can be used as an extraction solvent to extract polyphenolic compounds from plants under pressure of 4-6 MPa and temperature of 120-220℃. No organic solvent needs to be added during the extraction process, which effectively improves the extraction rate of polyphenolic compounds. Moreover, the extract does not contain organic solvent, thus achieving green extraction.

[0016] (2) This invention uses deuterium-rich water as a solvent for extraction at a pressure of 4-6 MPa and a temperature of 120-220°C. Under these conditions, the thermal motion of molecules is intensified, amplifying the kinetic isotope effect of deuterium-rich water, further enhancing its transdermal permeability, promoting the leaching of active ingredients from cells, and effectively increasing the extraction rate of polyphenolic compounds from Chinese medicinal materials. At the same time, this closed high-temperature and high-pressure extraction environment effectively isolates oxygen and significantly reduces the risk of compound oxidation. Complex material transformations occur during the extraction process. Increasing the temperature can increase the ion product of deuterium-rich water, giving it a strong acid-base catalytic function under high temperature and high pressure. This can promote the hydrolysis of flavonoids (i.e., flavonoid glycosides) in the form of glycosides, thereby increasing the yield of hydrolysis products such as apigenin, luteolin, quercetin, rutin, hyperoside, and other polyphenolic compounds, thus increasing the amount of flavonoids extracted. Furthermore, combined with its enhanced permeability and unique acid-base catalytic properties, low-deuterium water under high temperature and high pressure can also achieve efficient extraction of polyphenolic compounds, including both free and bound forms, greatly increasing the extraction rate.

[0017] (3) The present invention uses low-deuterium water with a deuterium concentration of less than 138 ppm as the extraction solvent. Since the deuterium concentration is less than 138 ppm, the surface tension of the water is different, resulting in molecular clusters of different sizes and numbers. The molecular clusters of low-deuterium water are more than 50% smaller than those of ordinary water, and its transdermal ability is higher. It can more effectively promote the extraction of various polyphenolic active ingredients through the cell barrier, which can greatly improve the extraction rate of polyphenolic compounds.

[0018] (4) In this invention, low-deuterium water is used as a solvent and the extraction is carried out at a pressure of 4-6 MPa and a temperature of 120-220℃ for 10-120 min. The extraction time is controlled within 10-120 min. Within this time, polyphenolic compounds in plants can be effectively extracted, and the degradation and decomposition of active ingredients by high temperature and high pressure can be reduced, thus ensuring the extraction amount of active ingredients. Attached Figure Description

[0019] Figure 1 Chromatogram of polygala extract polygala glycoside;

[0020] Figure 2 Chromatogram of resveratrol, an extract of Polygonum cuspidatum;

[0021] Figure 3 Chromatogram of neohesperidin in the extract of Citrus aurantium;

[0022] Figure 4 Chromatogram of rutin in the extract of Citrus aurantium;

[0023] Figure 5 Chromatogram of hesperidin in the extract of Citrus aurantium;

[0024] Figure 6Chromatogram of buddleja glycosides in wild chrysanthemum extract;

[0025] Figure 7 Chromatoglycine in wild chrysanthemum extract;

[0026] Figure 8 Chromatogram of chlorogenic acid in wild chrysanthemum extract. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to specific embodiments.

[0028] Example 1

[0029] This embodiment uses Houttuynia cordata as raw material to extract polyphenolic compounds from it. The specific steps are as follows:

[0030] Take 0.5g of Houttuynia cordata, dry and pulverize it into granules with a particle size of 60-100 mesh, and add it to the extraction tank. Add low-deuterium water with a deuterium concentration of 100 ppm as the extraction solvent at a material-to-liquid ratio of 1:30. Extract for 120 min at a constant pressure of 5 MPa and a constant temperature of 200℃. After cooling and depressurization, open the extraction tank and filter through a Buchner funnel to obtain the filtrate. Centrifuge the filtrate at 4000 r / min for 5 min, collect the supernatant, and store it in a refrigerator for later use. The extract was determined, and its polyphenolic compounds were chlorogenic acid, gallic acid, sinigrin, and quercetin. The total results are shown in Table 1.

[0031] The methods for determining the compounds are as follows:

[0032] Instrument model: Shimadzu LC-20T high performance liquid chromatography;

[0033] Detection conditions: Mobile phase: Organic phase: Methanol (B); Aqueous phase: 0.1% formic acid solution (A);

[0034] Chromatographic conditions: Flow rate: 1 ml / min, column temperature: 35℃;

[0035] Gradient program: 0-5 min: 10% B; 5-10 min: 10% B - 25% B; 10-18 min: 25% B - 35% B;

[0036] 18-25min: 35%B-48%B, 25-30min: 48%B-52%B.

[0037] Example 2

[0038] In this embodiment, Polygonum cuspidatum was used as raw material, and deuterium-free water was used to extract polyphenolic compounds from it. The specific steps are as follows:

[0039] Take 0.5g of Polygonum cuspidatum, dry and pulverize it into granules with a particle size of 60-100 mesh, and add it to the extraction tank. Add low-deuterium water with a deuterium concentration of 100 ppm as the extraction solvent at a material-to-liquid ratio of 1:15. Extract for 120 minutes at a constant pressure of 5 MPa and a constant temperature of 180℃. After cooling and depressurizing, open the extraction tank and filter the solution through a Buchner funnel to obtain the filtrate. Centrifuge the filtrate at 4000 r / min for 5 minutes and collect the supernatant. Store it in a refrigerator for later use.

[0040] The extract was analyzed, and its compounds were identified as polygalactoside and resveratrol. The total content results are summarized in Table 1, and the chromatogram is shown in the figure. Figure 1 , Figure 2 .

[0041] The methods for determining the compounds are as follows:

[0042] Instrument model: Shimadzu LC-20T high performance liquid chromatography;

[0043] Detection conditions: Mobile phase: Organic phase: Acetonitrile (B); Aqueous phase: 0.1% phosphoric acid solution (A);

[0044] Chromatographic conditions: Flow rate: 1 ml / min, column temperature: 35℃;

[0045] Gradient program: 0-5 min: 10%B; 5-20 min: 10%B-40%B; 20-25 min: 40%B-48%B;

[0046] 25-28 min: 48% B-55% B.

[0047] Example 3

[0048] This embodiment uses wild chrysanthemum as raw material to extract polyphenolic compounds from chrysanthemum. The specific steps are as follows:

[0049] Take 0.5g of wild chrysanthemum, dry and pulverize it into granules with a particle size of 60-100 mesh, and add it to the extraction tank. Add low-deuterium water with a deuterium concentration of 100 ppm as the extraction solvent at a material-to-liquid ratio of 1:20. Extract for 60 minutes at a constant pressure of 5 MPa and a constant temperature of 180℃. After cooling and depressurization, open the extraction tank and filter through a Buchner funnel to obtain the filtrate. Centrifuge the filtrate at 4000 r / min for 5 minutes, collect the supernatant, and store it in a refrigerator for later use. The extract was analyzed for polyphenolic compounds, which were found to be luteolin, luteolin, and chlorogenic acid. The total content results are shown in Table 1. The chromatograms of each component are shown below. Figure 6 , 7 As shown in Figure 8.

[0050] The methods for determining the compounds are as follows:

[0051] Instrument model: Shimadzu LC-20T high performance liquid chromatography;

[0052] Detection conditions: Mobile phase: Organic phase: Acetonitrile (B); Aqueous phase: 0.1% formic acid solution (A);

[0053] Detection: 0-5 min: 10% B; 5-15 min: 10% B-30% B; 15-25 min: 30% B-40% B; 25-35 min: 40% B-49% B;

[0054] 35-40min: 49%-56%B.

[0055] Example 4

[0056] This embodiment uses Citrus reticulata as raw material to extract polyphenolic compounds from it. The specific steps are as follows:

[0057] Take 0.5g of dried and pulverized *Citrus reticulatae* (Citrus spp.) to a particle size of 60-100 mesh and add it to the extraction tank. Add deuterium-rich water (100 ppm) as the extraction solvent at a material-to-liquid ratio of 1:20. Extract for 60 minutes at a constant pressure of 5 MPa and a constant temperature of 180°C. After cooling and depressurization, open the extraction tank and filter through a Buchner funnel to obtain the filtrate. Centrifuge the filtrate at 4000 rpm for 5 minutes and collect the supernatant. Store in a refrigerator for later use. Determine the polyphenolic compounds in the extract. Neohesperidin, rutin, and hesperidin were found. Their chromatograms are shown below. Figure 3 , 4 As shown in Figure 5, the total content results are statistically presented in Table 1.

[0058] The methods for determining the compounds are as follows:

[0059] Instrument model: Shimadzu LC-20T high performance liquid chromatography;

[0060] Detection conditions: Mobile phase: Organic phase: methanol; Aqueous phase: 0.1% formic acid water; Flow rate: 1 ml / min; Column temperature: 30℃.

[0061] Detection procedure: 0-15 min: 10%B-30%B; 15-35 min: 30%B-48%B; 35-40 min: 48%B-55%B;

[0062] 40-54 min: 55% B-77% B.

[0063] Table 1

[0064]

[0065] In their research on the extraction of polyphenolic compounds using low-deuterium water, the inventors conducted experiments to verify the deuterium concentration of the low-deuterium water, the ratio of the extraction material to the liquid, temperature, pressure, and extraction time.

[0066] Single-factor experiment on the extraction of polyphenolic compounds from houttuynia cordata

[0067] Experimental Example 1

[0068] This experimental example, based on Example 1, used Houttuynia cordata as raw material and maintained the same extraction conditions, employing pure water (deuterium concentration 150 ppm), and low-deuterium water at concentrations of 138 ppm, 100 ppm, 50 ppm, and 25 ppm. The extraction yields of polyphenolic compounds at each concentration are shown in Table 2 below:

[0069] Table 2

[0070]

[0071] Experiment Example 2

[0072] Based on Example 1, this experimental example used 100 ppm deuterated water as the extraction solvent, and extracted at 10 ml / g, 20 ml / g, 30 ml / g, 40 ml / g, and 50 ml / g at 180℃ and 5 MPa for 90 min. The extracts were measured, and the results are shown in Table 3.

[0073] Table 3:

[0074]

[0075] Experimental Example 3

[0076] Based on Example 1, this embodiment extracts polyphenolic compounds for 0.5-3 hours at a material-to-liquid ratio of 20 ml / g, 180℃, and 5 MPa. The results are shown in Table 4.

[0077] Table 4:

[0078]

[0079] Experiment Example 4

[0080] Based on Example 2, this experimental example uses a material-to-liquid ratio of 20 ml / g and is extracted for 1.5 h at 5 MPa and 100-220 °C. The results of the polyphenol compound content in the extract are shown in Table 5.

[0081] Table 5:

[0082]

[0083] Single-factor experiment on the extraction of polyphenolic compounds from Polygonum cuspidatum

[0084] Experimental Example 5

[0085] This experimental example, based on Example 2, also used Polygonum cuspidatum as raw material and kept the extraction conditions unchanged, employing pure water (deuterium concentration 150 ppm), and low-deuterium water at concentrations of 138 ppm, 100 ppm, 50 ppm, and 25 ppm. The extraction yields of phenolic and flavonoid compounds at each concentration are shown in Table 6 below:

[0086] Table 6

[0087]

[0088] Experimental Example 6

[0089] This implementation, based on Example 2, used 100 ppm deuterium-rich water as the extraction solvent, and extracted for 120 min at concentrations of 10 ml / g, 15 ml / g, 20 ml / g, 25 ml / g, 30 ml / g, 30 ml / g, 35 ml / g, 40 ml / g, and 50 ml / g, respectively. The extraction results are summarized in Table 7.

[0090] Table 7

[0091]

[0092] Experimental Example 7

[0093] Based on Example 2, this embodiment uses a material-to-liquid ratio of 20 ml / g and extraction conditions of 180℃ and 5 MPa for 0.5-3 h. The extraction results are summarized in Table 8.

[0094] Table 8

[0095]

[0096] Experimental Example 8

[0097] Based on Example 2, this experimental example uses a material-to-liquid ratio of 20 ml / g and is extracted at 5 MPa and 100-220℃ for 1.5 h. The extraction results are shown in Table 9.

[0098] Table 9

[0099]

[0100] Single-factor experiment on the extraction of polyphenolic compounds from bitter orange peel

[0101] Experimental Example 9

[0102] This experimental example, based on Example 2, also used total Citrus aurantium as raw material and kept the extraction conditions unchanged, employing pure water (deuterium concentration 150 ppm), and low-deuterium water at concentrations of 138 ppm, 100 ppm, 50 ppm, and 25 ppm. The extraction yields of phenolic and flavonoid compounds at each concentration are shown in Table 10 below.

[0103] Table 10

[0104]

[0105] Experimental Example 10

[0106] This embodiment, based on Example 4, investigates the effect of the solid-liquid ratio on the extraction results by extracting at 5 MPa and 180℃ for 1.5 h at solid-liquid ratios ranging from 10 ml / g to 50 ml / g. The results for the polyphenolic compounds in the extract are shown in Table 11.

[0107] Table 11:

[0108]

[0109] Experimental Example 11

[0110] Based on Example 4, this embodiment uses a material-to-liquid ratio of 20 ml / g, extraction at 180℃ and 5 MPa for 0.5-3 h, and determines the content of polyphenolic compounds in the extract. The results are summarized in Table 12.

[0111] Table 12:

[0112]

[0113] Experimental Example 12

[0114] Based on Example 2, this experimental example used a material-to-liquid ratio of 20 ml / g and extraction at 5 MPa and 100-220℃ for 1.5 h. The results of the determination of polyphenolic compounds in the extract are shown in Table 13.

[0115] Table 13:

[0116]

[0117] Comparative Example 1

[0118] In this comparative example, polyphenolic compounds were extracted from Houttuynia cordata, Polygonum cuspidatum, Citrus aurantium and Chrysanthemum indicum using reflux extraction. The reflux extraction parameters were 70% ethanol (75% ethanol for Polygonum cuspidatum), a solid-liquid ratio of 1:20, and an extraction time of 2 hours at 85°C.

[0119] Comparative Example 2

[0120] This embodiment describes the use of ultrasound-assisted extraction to extract polyphenolic compounds from Houttuynia cordata, Polygonum cuspidatum, Citrus aurantium, and Chrysanthemum indicum. The ultrasound extraction parameters were: 70% ethanol, solid-liquid ratio of 1:20, extraction at 100W for 50 min, and Polygonum cuspidatum extraction for 40 min.

[0121] Comparative Example 3

[0122] In this comparative example, polyphenolic compounds were extracted from four medicinal materials by reflux extraction using 100 ppm low-deuterium water at atmospheric pressure and 100°C, under the conditions of Examples 1-4.

[0123] Comparative Example 4

[0124] In this comparative example, polyphenolic compounds were extracted from four medicinal materials by reflux extraction using 25 ppm low-deuterium water at atmospheric pressure and 100°C, under the conditions of Examples 1-4.

[0125] The results of Comparative Examples 1, 2, 3 and 4 are shown in Table 14.

[0126] Table 14:

[0127]

[0128] Results Analysis

[0129] The results in Tables 2, 6, and 10 show that the present invention uses low-deuterium water with a deuterium concentration of less than 138 ppm to extract polyphenolic compounds from plants, which has a high extraction efficiency and obvious advantages over pure water extraction, while keeping the extraction conditions unchanged. As the concentration of low-deuterium water decreases, the total phenol content gradually increases.

[0130] The results in Tables 3, 7, and 11 show that polyphenol compounds can be effectively extracted within a material-to-liquid ratio range of 1:10-50 ml / g. The optimal material-to-liquid ratio varies for different Chinese herbal medicines. Specifically, the optimal material-to-liquid ratio for extracting total phenols from Houttuynia cordata is 1:30; for Polygonum cuspidatum, it is 1:15; and for Citrus aurantium, it is 1:20.

[0131] As shown in Tables 4, 8, and 12, this invention uses low-deuterium water at 180-200℃ to extract polyphenolic compounds from various plants. The extraction yield in the shortest time (10 minutes) is comparable to that of existing reflux extraction methods. The extraction yield gradually increases with increasing extraction time. Specifically, the optimal extraction time for total phenols from Houttuynia cordata and Polygonum cuspidatum is 2 hours; the optimal extraction time for total phenols from Citrus aurantium is 1 hour. Beyond the optimal extraction time, the extraction yield decreases. Compared to existing conventional reflux extraction (which requires multiple extractions over 2-4 hours), the extraction efficiency is significantly improved.

[0132] As shown in Tables 5, 9, and 13, under the method of this invention, the content of polyphenolic compounds in plant species gradually increases when the pressure is 5 MPa and the temperature is greater than 120℃. In particular, the extraction effect is best when the temperature is between 180-200℃. When the temperature exceeds 200℃, the active ingredients decompose and the measured content of active ingredients decreases to a certain extent. Therefore, the extraction temperature is best controlled within 200℃.

[0133] As shown in Tables 1 and 14, Examples 1-4 yielded the highest extraction content using the method of this invention, significantly superior to reflux extraction and ultrasound-assisted extraction. It also exhibits clear advantages over pure water extraction. Low-deuterium water (deuterium content less than 100 ppm) extracted even more active ingredients. Although Comparative Examples 3 and 4 used low-deuterium water as a solvent, the polyphenol content obtained under normal pressure and 100℃ conditions was only slightly better than that of Comparative Examples 1 and 2. This demonstrates that low-deuterium water, under the high temperature and high pressure conditions of this invention, has a significant advantage in extracting polyphenols from Chinese medicinal materials. Furthermore, the extract contains no organic solvents, achieving green extraction. Compared to existing methods such as ultrasound extraction and reflux extraction, under the same extraction time, the method of this invention can obtain more than 4 times the total phenol content compared to reflux extraction and more than 2.5 times compared to ultrasound-assisted extraction. This achieves high-quality conversion of active ingredients.

[0134] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications and substitutions based on the technical solutions and inventive concepts provided by the present invention should be covered within the scope of protection of the present invention.

Claims

1. The application of deuterium-low water as an extraction solvent in the extraction of polyphenolic compounds from plants, wherein the extraction is carried out at a pressure of 4-6 MPa and a temperature of 120-220°C, and the deuterium concentration of the deuterium-low water is less than or equal to 138 ppm.

2. The application according to claim 1, characterized in that: The deuterium concentration of the low-deuterium water is less than or equal to 100 ppm.

3. The application according to claim 1, characterized in that: The deuterium concentration of the low-deuterium water is less than or equal to 25 ppm.

4. The application according to claim 1, characterized in that: The extraction is carried out at a material-to-liquid ratio of 1:10-50 ml / g, and the extraction time is 10 min-120 min.

5. The application according to claim 1, characterized in that: The plants include Chinese herbal medicines, tea, vegetables and fruits, and the Chinese herbal medicines include Polygonum cuspidatum, Houttuynia cordata, Citrus aurantium, Chrysanthemum indicum, Citrus medica, and Guava.

6. A method for extracting polyphenolic compounds from plants, characterized in that: Plant powder and extraction solvent are selected at a material-to-liquid ratio of 1:10-50 ml / g, added to an extraction tank and mixed evenly. The mixture is then extracted for 10-120 minutes at a temperature of 120-220℃ and a pressure of 4-6 MPa. The extract is filtered and centrifuged to obtain an extract containing polyphenolic compounds. The extraction solvent is low-deuterium water with a deuterium concentration of less than or equal to 138 ppm, preferably with a deuterium concentration of less than or equal to 100 ppm.

7. The method for extracting polyphenolic compounds from plants according to claim 6, characterized in that: The particle size of the plant powder is controlled at 60-100 mesh.

8. The method for extracting polyphenolic compounds from plants according to claim 6, characterized in that: The centrifugation is performed by centrifuging the filtered extract at 4000 r / min for 5 min.

9. A method for extracting polyphenolic compounds from plants according to claim 6, characterized in that: It also includes concentration, which involves evaporating the supernatant obtained by centrifugation under reduced pressure at a temperature of 60°C to concentrate it into a paste.

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