Preparation method and application of rumex hanus selenium polysaccharide

Abstract

The invention relates to the technical field of food and medicine, and discloses a rumex hanus selenium polysaccharide preparation method, which comprises: S1, solution preparation: placing refined rumex hanus polysaccharide in a cleaned and sterilized glass or ceramic container, and selecting the container as the chemical stability of the refined rumex hanus polysaccharide is strong so as to prevent the reaction with the polysaccharide from affecting the product quality, distilled water subjected to multi-stage filtration and distillation treatment is slowly added, water is added while stirring is conducted through a glass rod, in order to accelerate dissolution, the water temperature can be controlled to range from 30 DEG C to 40 DEG C, but it needs to be avoided that the polysaccharide structure is damaged due to too high temperature till polysaccharide is completely dissolved to form a uniform solution; s2, reagent addition: sodium selenite is added into the polysaccharide solution according to the weight ratio of the refined rumex hanus polysaccharide to the sodium selenite being (1-2): (0.1-2), and the ratio is determined through a large number of experiments. The invention provides the brand-new rumex hanus selenium polysaccharide and the preparation method thereof, and a theoretical basis is provided for subsequent industrial production and further research.

Description

Technical Field

[0001] The present invention relates to the technical field of food and medicine, and in particular to a preparation method and application of leaf-eating grass selenium polysaccharide. Background Art

[0002] The innovative leaf-eating grass (protein grass) plant, Rumex hanus by., scientifically known as leaf-eating grass, is named "leaf-eating grass" for its juicy, spinach-like leaves, which contain numerous nutrients. Its primary food source is the leaf-eating grass. It is also known as "protein grass" because of its highest protein content among plants; in southern China, it is called "leaf-eating vegetable." Rumex hanus plants are mentioned in medical classics throughout my country, and have been used as food and medicine since ancient times. Leaf-eating grass is rich in amino acids, proteins, vitamins, potassium, selenium, calcium, iron, phosphorus, zinc, magnesium, manganese, and copper, essential elements for plants. The roots of leaf-eating grass also contain medicinally active ingredients such as alkaloids and anthraquinones, demonstrating its remarkable clinical value in antibacterial and anti-inflammatory treatments, trauma, and burns. It plays a vital role in future ecological agriculture, green food production, and biopharmaceutical production, and holds immense promise for its application.

[0003] Leafy grass, also known as protein grass, is rich in nutrients, boasting a protein content of up to 36.1%. It is also rich in amino acids, proteins, vitamins, chlorophyll, chlorogenic acid, emodin, dietary fiber, isoflavones, SOD, and beneficial minerals and trace elements such as potassium, calcium, iron, selenium, zinc, phosphorus, magnesium, manganese, and copper. Its comprehensive nutritional profile is highly absorbable and effective, resulting in rapid results. Its nutritional profile is among the highest among plants currently available. Leafy grass is highly selenium-rich, containing the golden trace element selenium, as well as SOD and isoflavones. These ingredients play a vital role in anti-aging, antioxidant, anti-cancer, and reducing the three highs. Rumex species of the genus Rumex, such as Rumex serrata, Rumex obtusifolia, Rumex chinense, Rumex bartianensis, and Rumex serrata root, are widely used as herbal remedies known as "rhubarb." They possess numerous benefits, including clearing heat and detoxifying, antibacterial and antipruritic properties, and promoting blood circulation and hemostasis. They are used to treat hemorrhagic disorders and scabies.

[0004] Selenium is an essential trace element for the human body, but inorganic selenium is toxic and has a small safe dose. Organic selenium compounds are a new type of compound with pharmacological activities such as antiviral, anti-tumor, anti-inflammatory, anti-aging, growth promotion, protection of visual organs, detoxification, prevention and treatment of cardiovascular diseases and prevention of liver diseases. Selenium has unique biochemical properties and pharmacological effects, and the development of selenium-containing compounds is of great significance.

[0005] Selenium polysaccharide is an organic selenium compound, which has the activity of both selenium and polysaccharide. Selenium polysaccharide has many physiological activities such as antagonizing heavy metals, in vitro antioxidant, enhancing or regulating body immunity, antitumor, antiviral, hypoglycemic effect, etc. It is a good biological selenium supplement and has important significance in the development of health care products and drugs. At present, selenium polysaccharide has been used in clinical treatment, and the development of selenium polysaccharide health care products and drugs has been carried out, such as compound selenium polysaccharide capsules.

[0006] There is no report on the preparation of seleniumized food leaf grass polysaccharide, and the preparation method of food leaf grass selenium polysaccharide has important practical significance for the in-depth development of food leaf grass polysaccharide and its selenium polysaccharide products.

[0007] Therefore, it is necessary to design a food leaf grass selenium polysaccharide preparation method and application with strong practicability. SUMMARY

[0008] The purpose of the present application is to provide a food leaf grass selenium polysaccharide preparation method and application to solve the problems in the above background art.

[0009] In order to solve the above technical problems, the present application provides the following technical scheme: a food leaf grass selenium polysaccharide preparation method, comprising the following steps: S1: solution preparation The refined food leaf grass polysaccharide is placed in a glass or ceramic container after washing and sterilization. Such containers are selected because of their strong chemical stability, which can prevent reaction with polysaccharide and affect the quality of the product. Distilled water treated by multi-stage filtration and distillation is slowly added, and stirring is carried out with a glass rod while adding water. In order to accelerate dissolution, the water temperature can be controlled at 30-40℃, but the temperature should be avoided to be too high to damage the structure of polysaccharide. Until the polysaccharide is completely dissolved to form a uniform solution. S2: reagent addition According to the weight ratio of refined food leaf grass polysaccharide: sodium selenite = 1-2:0.1-2, sodium selenite is added to the polysaccharide solution. This ratio is determined by a large number of experiments, which can ensure the combination of selenium and polysaccharide, and at the same time avoid the waste and safety risk caused by excessive sodium selenite. After adding, continue to stir to make it evenly dispersed. According to the weight ratio of refined food leaf grass polysaccharide: cation exchange resin = 1:0.1-1.5, cation exchange resin is added to the solution as a catalyst. The amount of catalyst needs to be strictly controlled. Improper amount of catalyst will affect the reaction process and subsequent separation and purification. S3: reaction The container containing the solution is placed in a constant temperature magnetic stirrer or water bath, and the reaction temperature is controlled at 50-80℃ for continuous heating and stirring. This temperature range can provide the energy required for the reaction and accelerate the reaction rate, and at the same time maintain the stability of polysaccharide and selenium compounds. The reaction time is 3-24h. During the reaction, the concentration of reactants and the amount of product generated can be detected periodically to determine the optimal reaction time. S4: Product processing After the reaction is completed, stop heating immediately and use filtration, centrifugation and other methods to separate the cation exchange resin and other catalysts from the solution. Transfer the separated solution to a clean sealed container and cool it naturally to room temperature to obtain the phyllophora selenium polysaccharide solution. Be careful to prevent the solution from being contaminated during cooling.

[0010] According to the above technical solution, the selenium content in the leaf-eating grass selenium polysaccharide is 0.5 to 4.0 mg / g.

[0011] According to the above technical solution, the cation exchange resin is hydrogen type 732 ion exchange resin.

[0012] According to the above technical solution, the reaction temperature for heating and stirring is 60°C; and the reaction time is 3 hours.

[0013] According to the above technical solution, the ratio of the refined foliage grass polysaccharide to sodium selenite is 1.5:0.5 or 1:0.3.

[0014] According to the above technical solution, when the ratio of refined foliar grass polysaccharide to sodium selenite is 1.5:0.5, the ratio of refined foliar grass polysaccharide to cation exchange resin is 1:0.5; when the ratio of refined foliar grass polysaccharide to sodium selenite is 1:0.3, the ratio of refined foliar grass polysaccharide to cation exchange resin is 1:2.0.

[0015] According to the above technical scheme, the preparation method of the refined foliar grass polysaccharide is as follows: the crude foliar grass polysaccharide is redissolved in water, 0.2% of the weight of the crude foliar grass polysaccharide α-amylase powder is added, and the reaction is stirred until no starch is contained; then sevage reagent is added to remove the protein, and the sevage reagent is removed by vacuum concentration to obtain a crude foliar grass polysaccharide solution with starch and protein removed, and then the solution is concentrated to 1 / 5 of the original volume, and anhydrous ethanol is added to adjust the alcohol content to 85% to obtain a white flocculent polysaccharide, and then frozen, decompressed, filtered, and dried to obtain refined foliar grass polysaccharide.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are: 1. The present invention provides a new leaf-eating grass selenium polysaccharide and its preparation method, which provides a theoretical basis for subsequent industrial production and further research.

[0017] 2. The present invention provides a new catalyst for polysaccharide selenization reaction, which is easy to put into industrial production and provides a theoretical basis for further in-depth research.

[0018] 3. The present invention proposes for the first time that the more selenium in selenium polysaccharides, the better, and discloses that the optimal selenium content in folivorous grass selenium polysaccharides is 3 mg / g, which has important practical significance for the subsequent practical application of folivorous grass selenium polysaccharides in humans / animals; it has important guiding significance for the preparation of other selenium polysaccharides.

[0019] 4. The present invention found that when the weight ratio of foliage grass polysaccharide: sodium selenite: cation exchange resin = 1:0.3:2.0, the prepared foliage grass selenium polysaccharide has the characteristics of appropriate selenium content and extremely high yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 This is a monosaccharide composition diagram of edible leaf grass polysaccharides; Figure 2 This is the infrared spectrum of the refined foliage grass polysaccharide; Figure 3 This is the infrared spectrum of sodium selenite; Figure 4 The infrared spectrum of selenium polysaccharide from edible leaf grass; Figure 5 The infrared spectra of edible leaf grass polysaccharide, sodium selenite, and edible leaf grass selenium polysaccharide; Figure 6 This is the standard curve of selenium content; Figure 7 Schematic diagram of the antioxidant capacity of foliar grass polysaccharides and foliar grass selenium polysaccharides; Figure 8 Schematic diagram of the blood sugar lowering ability of edible leaf selenium polysaccharides. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] The operating steps of the present invention are as follows: 1. Extraction of polysaccharides from foliage grass The leaves of the leaf-eating grass are cut into 1-2 cm pieces, broken by a beater, boiled, filtered through a 100 mesh screen, and the residue is washed with hot water (70°C or higher) until the residue is not sticky and does not contain polysaccharides. The filtrate and the washing liquid are combined to obtain the leaf-eating grass extract, which is concentrated by a rotary evaporator at about 65°C under reduced pressure. While stirring, anhydrous ethanol is added to the concentrated liquid until the alcohol content is 80% or higher. Floc-like precipitates gradually form, and the mixture is refrigerated for 2 hours or more. The mixture is filtered under reduced pressure, and the precipitates are repeatedly washed with alcohol until no more pigments are present. The precipitates are dried to obtain the crude polysaccharides of the leaf-eating grass.

[0023] 2. Purification of the crude polysaccharides of the leaf-eating grass The crude polysaccharides of the leaf-eating grass obtained in step 1 are dissolved in water, and 0.2% of α-amylase (dry powder) by weight of the crude polysaccharides is added. The mixture is stirred at 55-65°C to hydrolyze the starch, and iodine water is used to detect the presence of starch. Sevage (V / V, n-butanol: chloroform = 1:4) reagent is added to remove proteins, and the n-butanol and chloroform are removed by concentration under reduced pressure at 60°C. The polysaccharide solution after removing the starch and proteins is concentrated to 1 / 5 of the original volume, and anhydrous ethanol is added to adjust the alcohol content to 80%. White floc-like polysaccharides are obtained, which are refrigerated for 2 hours or more, filtered under reduced pressure, and dried in an oven at 70°C to obtain the refined polysaccharides of the leaf-eating grass.

[0024] 3. Selenium reaction 1.0 g of the refined polysaccharides of the leaf-eating grass obtained in step 2 is weighed into a three-necked flask, dissolved in distilled water, and 0.1-1 g of sodium selenite and 0.5-2 g of cation exchange resin are added as a catalyst. The mixture is continuously heated and stirred for 2-24 hours, after which the heating is stopped, the catalyst is separated by filtration, and the reaction solution containing the selenium polysaccharides of the leaf-eating grass is obtained.

[0025] 4. Purification of the selenium polysaccharides of the leaf-eating grass The reaction solution obtained in step 3 is added to a 2000 Da dialysis bag, and distilled water is used for dialysis until the pH test paper is neutral and the dialysis liquid is colorless, indicating that the sodium selenite has been removed. The solution in the dialysis bag is freeze-dried to obtain the selenium polysaccharides of the leaf-eating grass.

[0026] The present specification is further explained in conjunction with specific examples.

[0027] Example 1: Preparation of the polysaccharides of the leaf-eating grass (1) Take 500 g of fresh leaves of Eupatorium fortunei stems, cut into 2-3 cm long pieces, add water in batches, and boil in a beater. Filter, wash the residue with boiling water, combine the filtrate and wash residue liquid, and obtain a total of 5 L of polysaccharide extraction liquid. Concentrate to about 1 L, adjust the ethanol concentration to 80% by adding anhydrous ethanol, freeze the alcohol precipitation liquid, and filter. Wash the crude polysaccharide precipitate repeatedly with 80% ethanol to remove pigments and the like. Dissolve the polysaccharide in water to about 2 L, add 1.0 g of α-amylase powder at about 60°C, and stir to hydrolyze the starch. Add iodine water until no blue-black color is observed. Add Sevage reagent (n-butanol: chloroform = 1:4) at a volume ratio of 5:2 in a separatory funnel to remove protein. Repeat multiple times until the interface between the two phases contains no protein. Concentrate and remove the organic solvent. Concentrate to about 1 L, add anhydrous ethanol, and adjust the ethanol content to about 80% to obtain white flocculent polysaccharide. Freeze in a refrigerator for more than 2 h, filter, and dry in an oven at 70°C to obtain 34 g of white refined Eupatorium fortunei polysaccharide, with a yield of 6.8% based on fresh weight.

[0028] The monosaccharide composition was determined by HPLC method, and mainly composed of mannose and glucose, as shown in Figure 1 .

[0029] (2) The infrared spectrum of the refined Eupatorium fortunei polysaccharide is shown in Figure 2 . As can be seen from the figure, 3420 cm-1, 2888 cm-1, 1735 cm-1, 1636 cm-1, 1382 cm-1, 1254 cm-1, 1066 cm-1, 875 cm-1, 809 cm-1, and 612 cm-1 are the characteristic absorption peaks of Eupatorium fortunei polysaccharide.

[0030] Example Two: Preparation of Eupatorium fortunei selenium polysaccharide (1) Take 14 parts of refined Eupatorium fortunei polysaccharide from Example One, each 1 g, and dissolve in 50 mL of distilled water. After complete dissolution, add sodium selenite 0.1 g, 0.5 g, and 1 g, respectively, and then add hydrogen type 732 ion exchange resin 0.5 g, 1 g, 1.5 g, and 2 g, respectively. React for 2-24 h, then stop the reaction, filter out the catalyst, and transfer the reaction liquid to a 2000 Da dialysis bag. Dialyze with distilled water until the solution is neutral and Vc is colorless, indicating that the sodium selenite has been removed. Freeze-dry the dialysis liquid to obtain white long flocculent Eupatorium fortunei selenium polysaccharide.

[0031] The amounts of sodium selenite and hydrogen type 732 ion exchange resin added in each group, as well as the reaction temperature and reaction time, are shown in Table 1.

[0032]

[0033] It should be noted that the inventors in actual operation, the specific parameter combination of test far more than shown in Table 1. Due to space constraints, can not be put into the whole test in this specification, so only Table 1 in these representative data to illustrate the general law. Among them, the parameter selection of group 14, although not completely in accordance with the rules followed by other parameters in Table 1, but its final result is very special, so also included in Table 1. Because the test data of group 14 does not conform to the general law, in order to verify its repeatability, the inventors with the same parameters as group 14 as group 15, again carried out a test.

[0034] In addition, the inventors investigated a variety of cation exchange resin, can successfully complete the selenization reaction. But hydrogen type 732 cation exchange resin is relatively more affordable, easy to get, in order to facilitate, the specification is selected.

[0035] (2) Infrared spectrum analysis of selenium polysaccharide of Euphorbia helioscopia The infrared spectrum of sodium selenite is shown in Figure 3 ; Taking the selenium polysaccharide of Euphorbia helioscopia prepared by group 1 as an example, its infrared spectrum is shown in Figure 4 ; Combined with Figure 2 , the Figure 2 , 3 , 4 are integrated into the same figure, as shown in Figure 5 .

[0036] As can be seen from Figure 4 , 5 , the characteristic absorption of selenium polysaccharide of Euphorbia helioscopia is 3420cm- 1, 2892cm- 1, 1652cm- 1, 1382cm- 1, 1308cm- 1, 1247cm- 1, 1150cm- 1, 1065cm- 1, 1031cm- 1, 941cm- 1, 871cm- 1, 809cm- 1, 759cm- 1, 614cm- 1, etc. Analysis shows that after selenization reaction, the basic structure of polysaccharide does not change obviously, the aldehyde group in the polysaccharide molecule is attributed to 1735cm- 1, and after selenization, the peak at 1735cm- 1 disappears obviously, it is speculated that the aldehyde group in the molecule is gradually added by sodium selenite during the reaction process, and the selenium polysaccharide is characterized by 1147cm- 1, 1031cm- 1, 941cm- 1.

[0037] (3) Determination of selenization effect of each group.

[0038] 1) Determination of selenium content in selenium polysaccharide of Euphorbia helioscopia prepared in each group. Draw the standard curve of selenium content, as shown in Figure 6The atomic fluorescence test was performed on each group of selenium polysaccharide of Selaginella uncinata, and the content of selenium in each group was calculated. The determination and calculation method was carried out according to "Hydride Atomic Fluorescence Method" in GB 2009.03-017. The sample was prepared by microwave digestion method.

[0039] 2) Calculate the yield of selenium polysaccharide of Selaginella uncinata in each group.

[0040] The calculation formula is: yield = amount of selenium polysaccharide of Selaginella uncinata / mass of polysaccharide initially added * 100%. The selenium effect of each group is shown in Table 2.

[0041]

[0042] The inventors found that the content of selenium element is not the higher the better, when the selenium element exceeds 3mg / g, the selenium polysaccharide of Selaginella uncinata appears difficult to dissolve in water, which hinders the further use of subsequent pharmaceuticals and the like.

[0043] As can be seen from groups 1-3 in Table 2, the amount of sodium selenite added is positively correlated with the content of selenium in selenium polysaccharide of Selaginella uncinata. When 0.5g of sodium selenite is added to 1g of Selaginella uncinata polysaccharide, the content of selenium is closest to the critical value. As can be seen from groups 2, 4-6, the amount of cation exchange resin is negatively correlated with the yield of selenium polysaccharide of Selaginella uncinata, which may be due to the hydrolysis of Selaginella uncinata polysaccharide caused by hydrogen ions in the resin; under the condition that the selenization reaction proceeds normally, the addition of 0.5g of cation exchange resin to 1g of Selaginella uncinata polysaccharide can achieve good results. As can be seen from groups 7-13, temperature and reaction time have little effect on the selenization reaction. Generally, it is believed that the selenization reaction takes several hours or even more to complete, but using the technical scheme of the present application, the reaction can be basically completed in 2h, and continuing to extend the time will not significantly improve the yield or the content of selenium.

[0044] In addition, under the specific conditions of sodium selenite and hydrogen type 732 ion exchange resin in group 14, a higher amount of sodium selenite and a higher amount of cation exchange resin result in a higher content of selenium and a very high yield of selenium polysaccharide of Selaginella uncinata. The data of group 15 is almost identical to that of group 14, proving that the technical scheme is indeed reproducible.

[0045] Example Three: Antioxidant ability of Selaginella uncinata polysaccharide and Selaginella uncinata selenium polysaccharide The antioxidant performance of Selaginella uncinata selenium polysaccharide and Selaginella uncinata polysaccharide was investigated with hydroxyl radical clearance rate as an index. Among them, Selaginella uncinata polysaccharide was prepared in Example 1; Selaginella uncinata selenium polysaccharide was prepared in Example 2, group 2.

[0046] Each treatment group is shown as follows: (1) Blank control group: 1 mL water + 0.5 mL EDTA-Fe + 1 mL PBS + 1 mL saffron + 1 mL hydrogen peroxide; (2) Positive control group: 1 mL water + 0.5 mL EDTA-Fe + 1 mL PBS + 1 mL saffron + 1 mL PBS; (3) Polysaccharide group: 1 mL of phyllotaxus polysaccharide + 0.5 mL of EDTA-Fe + 1 mL of PBS + 1 mL of saffron + 1 mL of hydrogen peroxide; (4) Selenium polysaccharide group: 1 mL of foliar grass selenium polysaccharide + 0.5 mL of ETA-Fe + 1 mL of PBS + 1 mL of saffron + 1 mL of hydrogen peroxide.

[0047] Each group was shaken and reacted in a 37°C water bath for 30 minutes. The absorbance was measured at 520 nm. The solution contained PBS buffer (150 mM, pH 7.4), saffron (360 μg / mL), H₂O₂ (3%), and EDTA-Fe (2 mM). The EDTA-Fe and sample were dissolved in water, while the remaining solution was dissolved in PBS buffer. Hydroxyl radical scavenging rate = A sample / A control × 100%. Each data point was measured three times and the average was calculated.

[0048] Specific cleaning effects such as Figure 7 shown.

[0049] Depend on Figure 7 It can be seen that the phyllostachys polysaccharide and phyllostachys selenium polysaccharide prepared by the present invention both have good ability to scavenge hydroxyl free radicals and can be actually applied to anti-aging and other aspects.

[0050] Example 4: Hypoglycemic Ability of Selenium Polysaccharides from Leafy Grass The hypoglycemic effect of leafy grass selenium polysaccharide and leafy grass polysaccharide was investigated with blood sugar as an indicator. Among them, the leafy grass selenium polysaccharide was selected from the leafy grass selenium polysaccharide prepared in Example 2 and 3.

[0051] A diabetic mouse model was established (high-sugar and high-fat diet for 4 weeks, followed by two intraperitoneal injections of 80 mg / kg freshly prepared streptozotocin (STZ) solution dissolved in 0.1 mol / L citrate buffer, pH 4.5, within 72 h of the fifth week. Mice were considered to have type 2 diabetes when their fasting blood glucose level reached 11.1 mmol / L or higher). The mice were then given T2DM drugs by oral gavage (dosage: TGT-1# 0.3 ml / day; TGT-2# 0.3 ml / day). The fasting blood glucose levels of all mice were assessed using a glucometer for 4 weeks.

[0052] The results showed that compared with the model group, TGT-1# and TGT-2# could significantly reduce the blood glucose content of mice, which was basically consistent with the hypoglycemic trend of the positive drug metformin. The hypoglycemic effect was slightly lower than that of metformin, showing a strong hypoglycemic effect.

[0053] The effects of the two formulas TGT-1# and TGT-2# are comparable.

[0054] Depend on Figure 8 It can be seen that the leaf-eating grass selenium polysaccharides prepared by the present invention have good blood sugar-lowering ability.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing leaf-eating grass selenium polysaccharide, characterized by: The following steps are involved: S1: Solution preparation Place the refined foliage grass polysaccharide in a cleaned and sterilized glass or ceramic container. This type of container is chosen because it has strong chemical stability and can prevent reactions with the polysaccharide that affect the quality of the product. Slowly add distilled water that has been filtered and distilled at multiple stages, stirring with a glass rod while adding water. To accelerate dissolution, the water temperature can be controlled at 30-40°C, but it is necessary to avoid excessively high temperatures that will damage the polysaccharide structure, until the polysaccharide is completely dissolved to form a uniform solution. S2: Reagent addition Sodium selenite is added to the polysaccharide solution at a weight ratio of 1-2:0.1-2 for refined foliar grass polysaccharides. This ratio, determined through extensive experiments, ensures that selenium and polysaccharides are fully combined while avoiding waste and safety risks caused by excessive sodium selenite. After addition, continue stirring to ensure uniform dispersion. A cation exchange resin is added to the solution as a catalyst at a weight ratio of 1:0.1-1.5 for refined foliar grass polysaccharides. The amount used must be strictly controlled, as improper use will affect the reaction process and subsequent separation and purification. S3: Reaction proceeds Place the container containing the solution in a constant temperature magnetic stirrer or water bath, control the reaction temperature at 50-80°C and continue heating and stirring. This temperature range can provide the energy required for the reaction, accelerate the reaction rate, and maintain the stability of the polysaccharide and selenium compound. The reaction time is 3-24 hours. During this period, samples can be taken regularly to test the concentration of reactants and the amount of product generated to determine the optimal reaction time; S4: Product processing After the reaction is completed, stop heating immediately and use filtration, centrifugation and other methods to separate the cation exchange resin and other catalysts from the solution. Transfer the separated solution to a clean sealed container and cool it naturally to room temperature to obtain the phyllophora selenium polysaccharide solution. Be careful to prevent the solution from being contaminated during cooling.

2. The method for preparing a leaf-eating grass selenium polysaccharide according to claim 1, characterized in that: The selenium content of the leaf-eating grass selenium polysaccharide is 0.5-4.0 mg / g.

3. The method for preparing a leaf-eating grass selenium polysaccharide according to claim 1, characterized in that: The cation exchange resin is hydrogen type 732 ion exchange resin.

4. The method for preparing a leaf-eating grass selenium polysaccharide according to claim 1, characterized in that: The reaction temperature for heating and stirring is 60° C. and the reaction time is 3 h.

5. The method for preparing a leaf-eating grass selenium polysaccharide according to claim 1, characterized in that: The ratio of the refined foliage grass polysaccharide to sodium selenite is 1.5:0.5 or 1:0.

3.

6. The method for preparing a leaf-eating grass selenium polysaccharide according to claim 1, characterized in that: When the ratio of the refined foliar grass polysaccharide to sodium selenite is 1.5:0.5, the ratio of the refined foliar grass polysaccharide to cation exchange resin is 1:0.5; when the ratio of the refined foliar grass polysaccharide to sodium selenite is 1:0.3, the ratio of the refined foliar grass polysaccharide to cation exchange resin is 1:2.

0.

7. The method for preparing a leaf-eating grass selenium polysaccharide according to claim 1, characterized in that: The preparation method of the refined foliar grass polysaccharide comprises the following steps: re-dissolving crude foliar grass polysaccharide with water, adding α-amylase dry powder in an amount of 0.2% by weight of the crude foliar grass polysaccharide, stirring and reacting until no starch is contained; then adding sevage reagent to remove protein, concentrating under reduced pressure to remove the sevage reagent, thereby obtaining a crude foliar grass polysaccharide solution from which starch and protein are removed; then concentrating the solution to 1 / 5 of the original volume, adding anhydrous ethanol to adjust the alcohol content to 85% to obtain white flocculent polysaccharide, and then freezing, decompressing, filtering, and drying to obtain refined foliar grass polysaccharide.

8. A leaf-eating grass selenium polysaccharide, characterized in that Apply it to health products.

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