Houttuynia cordata extract as well as preparation method and application thereof

Abstract

The invention discloses a herba houttuyniae extract as well as a preparation method and application thereof, and relates to the technical field of water-soluble fertilizer preparation. The preparation method comprises the following steps: S1, cleaning herba houttuyniae, performing freeze drying, performing crushing, performing screening with a 80-120-mesh sieve, and performing enzymolysis treatment with compound enzyme; s2, taking an ethanol-alkali solution as a solvent, performing microwave heating to extract the enzymolysis material, and performing centrifugal separation to obtain a crude extract; s3, carrying out ultrafiltration membrane interception concentration treatment on the crude extract to obtain a houttuynia cordata concentrated solution; and S4, carrying out vacuum freeze drying on the cordate houttuynia concentrated solution to obtain the cordate houttuynia extract. According to the preparation method, the extraction time can be shortened by 80%, and compared with an existing method, the extraction rate of effective substances such as polysaccharide is remarkably increased; meanwhile, the water-soluble fertilizer obtained on the basis of the herba houttuyniae extract prepared by the preparation method disclosed by the invention can remarkably improve the soil environment, increase the granular structure of the soil, improve the water and fertilizer retention capability of the soil and provide better soil conditions for the growth of seeds.

Description

Technical Field

[0001] The present application relates to the technical field of water-soluble fertilizer preparation, and particularly relates to an houttuynia cordata extract, a preparation method thereof, and an application thereof. Background Art

[0002] Currently, commercially available water-soluble fertilizers mainly rely on the compounding of chemically synthesized nitrogen, phosphorus, potassium (NPK), trace elements, and inorganic salts. However, many problems still exist in actual applications. First, the nutrients in water-soluble fertilizers are easily fixed or leached by the soil, resulting in a usually low absorption and utilization rate of less than 30% by crops, causing serious waste of resources. Second, traditional fertilizer formulations often lack bioactive components and are difficult to effectively activate the plant stress resistance mechanism. Disease prevention and control still highly rely on chemical pesticides. In addition, trace elements such as Fe 2+ 、Cu 2 + are prone to react with phosphate radicals in this system to form precipitates, resulting in reduced or even ineffective fertilizer efficiency.

[0003] In recent years, some studies have attempted to introduce plant-derived active components such as alginic acid and humic acid into the water-soluble fertilizer system to improve its biological activity and nutrient utilization efficiency. As a medicinal and economic plant with unique biological activity, the roots of houttuynia cordata play an important role in the soil ecosystem. Its roots can secrete a large amount of metabolites such as organic acids, sugars, amino acids, low-molecular peptides, and exfoliated cells, especially rich in polysaccharide components, significantly increasing the content of organic matter in the rhizosphere soil, thereby improving the physical and chemical properties of the soil, providing rich carbon sources and energy for soil microorganisms, promoting the diversity and activity of the rhizosphere microbial community, and enhancing the stability of the soil ecosystem. However, in the process of using houttuynia cordata as a source of bioactive components for fertilizer development, several key technical bottlenecks still exist. First, the polysaccharide content in the houttuynia cordata extract obtained by the currently commonly used extraction process is not high, and the extraction efficiency is low, resulting in waste of resources. Second, the particle size of the crude extract is usually larger than 200 mesh, which is prone to cause excessive suspension particles during the compounding process and does not meet the water-soluble fertilizer standard. In addition, when compounding with trace elements, the mechanism of action between polysaccharides and chelating agents is not yet clear, resulting in large fluctuations in the chelation rate of trace elements and affecting the stability of product performance and application effects.

[0004] Therefore, it is necessary to develop a new preparation method for houttuynia cordata extract to achieve its efficient utilization in functional water-soluble fertilizers. Summary of the Invention

[0005] In view of this, the present invention provides a houttuynia cordata extract, a preparation method thereof and an application thereof. By optimizing the extraction process of the active ingredients of houttuynia cordata and establishing an efficient and stable complexing system with trace elements, the problems of low extraction rate, poor dispersibility and unstable chelation in the prior art are effectively solved, and the functionality and application stability in water-soluble fertilizers are improved.

[0006] The technical solution of the present invention is realized as follows: In a first aspect, the present invention provides a preparation method of a houttuynia cordata extract, comprising the following steps: S1. After washing houttuynia cordata, it is freeze-dried, pulverized and sieved through a 80-120 mesh sieve, and then enzymolysis treatment is carried out with a composite enzyme; S2. Using an ethanol-alkali solution as a solvent, the enzymolyzed material is extracted by microwave heating, and then centrifuged to obtain a crude extract; S3. After the crude extract is concentrated by ultrafiltration membrane retention, a houttuynia cordata concentrate is obtained; S4. After the houttuynia cordata concentrate is vacuum freeze-dried, a houttuynia cordata extract is obtained.

[0007] By adopting the above technical solution, the composite enzymolysis technology can destroy the plant cell wall structure and significantly improve the dissolution efficiency of polysaccharides and flavonoids; combined with the microwave-assisted extraction process of ethanol-alkali solution, high-efficiency extraction is realized under mild conditions, and the extraction rate and biological activity of the target components are significantly improved; further through ultrafiltration membrane concentration and vacuum freeze-drying treatment, not only macromolecular impurities and excess solvents are removed, but also a houttuynia cordata extract with uniform particle size distribution, high purity and good solubility is obtained.

[0008] In step S2 of the present invention, on the one hand, it helps to break the binding bonds between the active ingredients (such as polysaccharides and flavonoids) in plant cells and the cell wall or proteins, and at the same time maintain the structural stability of the target components, thus significantly improving the extraction efficiency and product activity; the alkaline environment can also assist in inhibiting the dissolution of some impurity components and reducing the subsequent purification difficulty; in addition, microwave-assisted heating can penetrate the material more evenly, accelerate the mass transfer process, and further improve the extraction rate and yield. On the other hand, it helps to achieve more uniform heat conduction and temperature control during the microwave extraction process, avoiding the degradation of polysaccharides and flavonoid active ingredients caused by local overheating; at the same time, intermittent heating can promote the temperature balance and solvent penetration between the inner and outer layers of the material, enhance the degree of cell wall rupture, and improve the dissolution efficiency of the target components; in addition, this heating mode can also effectively reduce the ethanol volatilization loss and maintain the stability of the extraction system, so as to improve the repeatability and safety of the process while ensuring the extraction rate and product activity.

[0009] Second aspect, the present invention relates to a houttuynia cordata extract prepared by the above preparation method. The houttuynia cordata extract can be adjusted according to actual needs by adjusting the addition ratio of clear water to obtain houttuynia cordata extraction solutions with different concentrations.

[0010] Third aspect, the present invention provides a water-soluble fertilizer based on houttuynia cordata extract, which includes the following components by mass parts: 280 - 300 parts of urea ammonium nitrate solution; 720 - 760 parts of the above houttuynia cordata extract; 40 - 60 parts of potassium dihydrogen phosphate; 15 - 25 parts of potassium hydroxide aqueous solution; 2 - 5 parts of kathon; 8 - 12 parts of hydroxyethylidene diphosphonic acid solution (HEDP); 5 - 8 parts of copper sulfate; 5 - 10 parts of ferrous sulfate; 5 - 10 parts of manganese sulfate; 1 - 1.5 parts of ammonium molybdate; 5 - 10 parts of zinc sulfate; 10 - 15 parts of borax.

[0011] By adopting the above technical solution, this fertilizer not only retains the biological activities of polysaccharides and flavonoid components in the houttuynia cordata extract, significantly improves plant stress resistance and rhizosphere microbial environment, but also enhances the solubility and stability of nutrients and reduces precipitation formation by optimizing the ratio of trace elements to chelating agents; meanwhile, the introduction of alkaline potassium hydroxide aqueous solution helps to maintain the pH stability of the system and improve the effectiveness of nutrient elements; kathon, as an efficient preservative, ensures the safety of long-term product storage.

[0012] Fourth aspect, the present invention relates to a preparation method of the above water-soluble fertilizer based on houttuynia cordata extract, which includes the following steps: By mass parts, after mixing the urea ammonium nitrate solution and the hydroxyethylidene diphosphonic acid solution, add potassium dihydrogen phosphate until dissolved, and then dropwise add the potassium hydroxide aqueous solution to the mixed solution. When the pH value of the mixed solution is 6.0 - 6.5, stop dropping. Subsequently, under the water bath condition of 25 - 30 °C, sequentially add the houttuynia cordata extract, copper sulfate, ferrous sulfate, manganese sulfate, zinc sulfate, borax and ammonium molybdate to it, and finally add kathon, stir in the dark, and pass through a 100-mesh sieve to obtain the water-soluble fertilizer based on houttuynia cordata extract.

[0013] By adopting the above technical solution, it is not only simple in operation, mild in conditions and good in compound stability, but also can achieve the efficient coordination of houttuynia cordata extract and inorganic nutrients, significantly improve the absorption and utilization rate, biological activity of the fertilizer and the promotion effect on crop stress resistance.

[0014] In summary, the present invention includes at least one of the following beneficial technical effects: 1. The method for preparing houttuynia cordata extract in the present invention can shorten the extraction time by 80%, and the extraction rate of effective substances such as polysaccharides is significantly improved compared with the existing preparation methods.

[0015] 2. The Houttuynia cordata extract prepared by the present invention can provide the energy, nutrients and polysaccharide components required for seed germination, thereby accelerating the seed germination process; and can have a positive impact on the growth of seedlings, accelerating the growth rate of seedlings, increasing the biomass and growth quality of seedlings by promoting root development and improving the photosynthesis efficiency of roots.

[0016] 3. The water-soluble fertilizer prepared by the present invention can significantly improve the soil environment, increase the soil aggregate structure, improve the water and fertilizer retention capacity of the soil, and provide better soil conditions for the growth of seeds. Description of the Drawings

[0017] Figure 1 It is the actual growth diagram of lettuce on the 7th day corresponding to Houttuynia cordata extract with different concentrations and clear water in Example 1 of the present application; Figure 2 It is the actual growth diagram of lettuce on the 7th day corresponding to Houttuynia cordata extract with different concentrations and clear water in Example 1 of the present application; Figure 3 It is the actual growth diagram of lettuce on the 15th day corresponding to Houttuynia cordata extract with different concentrations and clear water in Example 1 of the present application; Figure 4 It is the actual growth diagram of lettuce on the 15th day corresponding to Houttuynia cordata extract with different concentrations and clear water in Example 1 of the present application; Figure 5 It is the column analysis diagram of the above-ground part length of lettuce on the 15th day corresponding to Houttuynia cordata extract with different concentrations and clear water in Example 1 of the present application; Figure 6 It is the column analysis diagram of the root length of lettuce on the 15th day corresponding to Houttuynia cordata extract with different concentrations and clear water in Example 1 of the present application; Figure 7 It is the column analysis diagram of the fresh weight of lettuce on the 15th day corresponding to Houttuynia cordata extract with different concentrations and clear water in Example 1 of the present application; Figure 8 It is the actual growth diagram of lettuce on the 7th day corresponding to Cordyceps extract with different concentrations and clear water in Comparative Example 5; Figure 9 It is the actual growth diagram of lettuce on the 7th day corresponding to Cordyceps extract with different concentrations and clear water in Comparative Example 5; Figure 10 It is the actual growth diagram of lettuce on the 15th day corresponding to Cordyceps extract with different concentrations and clear water in Comparative Example 5; Figure 11 It is the actual growth diagram of lettuce on the 15th day corresponding to Cordyceps extract with different concentrations and clear water in Comparative Example 5; Figure 12Column analysis chart of the above-ground part length of lettuce corresponding to different concentrations of cordyceps extract and water in Comparative Example 5 on the 15th day; Figure 13 Column analysis chart of the root length of lettuce corresponding to different concentrations of cordyceps extract and water in Comparative Example 5 on the 15th day; Figure 14 Column analysis chart of the fresh weight of lettuce corresponding to different concentrations of cordyceps extract and water in Comparative Example 5 on the 15th day; Figure 15 Actual growth chart of wheat on the 7th day corresponding to 1 / 135 concentration of houttuynia cordata extract, 1 / 135 concentration of cordyceps extract and water; Figure 16 Actual growth chart of wheat on the 12th day corresponding to 1 / 135 concentration of houttuynia cordata extract, 1 / 135 concentration of cordyceps extract and water; Figure 17 Actual growth chart of wheat on the 15th day corresponding to 1 / 135 concentration of houttuynia cordata extract, 1 / 135 concentration of cordyceps extract and water; Figure 18 Actual growth comparison chart of wheat on the 15th day corresponding to 1 / 135 concentration of houttuynia cordata extract, 1 / 135 concentration of cordyceps extract and water; Figure 19 Column analysis chart of the above-ground part length of wheat on the 15th day corresponding to 1 / 135 concentration of houttuynia cordata extract, 1 / 135 concentration of cordyceps extract and water; Figure 20 Column analysis chart of the root length of wheat on the 15th day corresponding to 1 / 135 concentration of houttuynia cordata extract, 1 / 135 concentration of cordyceps extract and water; Figure 21 Column analysis chart of the fresh weight of wheat on the 15th day corresponding to 1 / 135 concentration of houttuynia cordata extract, 1 / 135 concentration of cordyceps extract and water; Figure 22 Actual growth chart of lettuce on the 1st day corresponding to 90-20-30 fertilizer and 90-20-30 fertilizer added with different concentrations of houttuynia cordata extract in Comparative Example 6; Figure 23 Actual growth chart of lettuce on the 9th day corresponding to 90-20-30 fertilizer and 90-20-30 fertilizer added with different concentrations of houttuynia cordata extract in Comparative Example 6; Figure 24 Actual growth chart of lettuce on the 18th day corresponding to 90-20-30 fertilizer and 90-20-30 fertilizer added with different concentrations of houttuynia cordata extract in Comparative Example 6; Figure 25It is the actual growth diagram of lettuce on the 22nd day corresponding to the 90-20-30 fertilizer in Comparative Example 6 and the 90-20-30 fertilizer added with different concentrations of Houttuynia cordata Thunb. extract; Figure 26 It is the actual growth diagram of lettuce on the 25th day corresponding to the 90-20-30 fertilizer in Comparative Example 6 and the 90-20-30 fertilizer added with different concentrations of Houttuynia cordata Thunb. extract; Figure 27 It is the actual growth diagram of lettuce on the 30th day corresponding to the 90-20-30 fertilizer in Comparative Example 6 and the 90-20-30 fertilizer added with different concentrations of Houttuynia cordata Thunb. extract; Figure 28 It is the statistical chart of the fresh weight of lettuce plants on the 30th day corresponding to the 90-20-30 fertilizer in Comparative Example 6 and the 90-20-30 fertilizer added with different concentrations of Houttuynia cordata Thunb. extract. Detailed implementation manners

[0018] Next, in combination with the implementation manners of the present invention, the technical solutions in the implementation manners of the present invention will be clearly and completely described. Obviously, the described implementation manners are only a part of the implementation manners of the present invention, rather than all of the implementation manners. Based on the implementation manners in the present invention, all other implementation manners obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0019] The following is a further description of the present invention in combination with specific embodiments. The scope of protection of the present invention is not limited by the following embodiments. Unless otherwise specified, the main materials involved in the following examples are all conventional commercially available products.

[0020] Cellulase is purchased from Novozymes, and its enzyme activity ≥ 500 U / mg; Pectinase is purchased from DuPont, and its enzyme activity ≥ 800 U / mg; The polyethersulfone membrane is purchased from Merck Millipore, and its molecular weight cut-off is about 10 - 50 kDa; Kathon is purchased from Lanxess, CMIT (5-chloro-2-methyl-4-isothiazolin-3-one) / MIT (2-methyl-4-isothiazolin-3-one) = 3:1, and the effective content ≥ 14%; Houttuynia cordata Thunb. preferably harvested from October to November is used.

[0021] The following are specific embodiments of the present invention.

[0022] Example 1 This example provides a preparation method of Houttuynia cordata Thunb. extract, including the following steps: S1. Take fresh Houttuynia cordata, wash it, freeze-dry it, crush it and sieve it through an 80-120 mesh sieve. Use a composite enzyme obtained by mixing cellulase and pectinase with a mass ratio of 2:1. Perform enzymatic hydrolysis at a pH value of 5.0 and a temperature of 45 °C for 50 min, then inactivate it in a 90 °C water bath for 5 min, and cool it to room temperature; S2. Use an ethanol solution with a mass fraction of 50%, add a 0.1 mol / L sodium bicarbonate solution to adjust the pH value of the ethanol solution to 8.7. Control the mass-volume ratio of the enzymatically hydrolyzed material to the ethanol-alkali solution to be 1 g:12 mL. Heat it at a microwave power of 500 w and a temperature of 45 °C for 13 min (stop for 10 s every 30 s of heating) for extraction, and then centrifuge to separate to obtain the supernatant, which is the crude extract; S3. After the crude extract is intercepted and concentrated by a polyethersulfone membrane (ultrafiltration membrane) at 0.2 MPa, obtain a Houttuynia cordata concentrated solution, and the volume of the Houttuynia cordata concentrated solution is 15% of the volume of the crude extract; S4. Pre-freeze the Houttuynia cordata concentrated solution at a vacuum of 10 Pa and -50 °C for 4 h, and then dry it at -20 °C for 18 h to obtain a Houttuynia cordata extract.

[0023] After testing, the polysaccharide content (phenol-sulfuric acid method) in the obtained extract is 32.6 wt%, the flavonoid content (aluminum salt colorimetric method) is 5.8 wt%, the particle size distribution is uniform, and the solubility is good.

[0024] Example 2 This example provides a preparation method of a Houttuynia cordata extract, including the following steps: S1. Take fresh Houttuynia cordata, wash it, freeze-dry it, crush it and sieve it through an 80-120 mesh sieve. Use a composite enzyme obtained by mixing cellulase and pectinase with a mass ratio of 1:1. Perform enzymatic hydrolysis at a pH value of 4.5 and a temperature of 45 °C for 60 min, then inactivate it in a 90 °C water bath for 5 min, and cool it to room temperature; S2. Use an ethanol solution with a mass fraction of 40%, add a 0.1 mol / L disodium hydrogen phosphate solution to adjust the pH value of the ethanol solution to 8.5. Control the mass-volume ratio of the enzymatically hydrolyzed material to the ethanol-alkali solution to be 1 g:10 mL. Heat it at a microwave power of 400 w and a temperature of 40 °C for 12 min (stop for 10 s every 30 s of heating) for extraction, and then centrifuge to separate to obtain the supernatant, which is the crude extract; S3. After the crude extract is intercepted and concentrated by a polyethersulfone membrane (ultrafiltration membrane) at 0.2 MPa, obtain a Houttuynia cordata concentrated solution, and the volume of the Houttuynia cordata concentrated solution is 10% of the volume of the crude extract; S4. Pre-freeze the Houttuynia cordata concentrated solution at a vacuum of 10 Pa and -50 °C for 4 h, and then dry it at -20 °C for 18 h to obtain a Houttuynia cordata extract.

[0025] After detection, the polysaccharide content in the obtained extract is 30.2 wt%, the flavonoid content is 5.1 wt%, the particle size distribution is uniform, and the solubility is good.

[0026] Example 3 This example provides a method for preparing Houttuynia cordata Thunb. extract, which includes the following steps: S1. Take fresh Houttuynia cordata Thunb., wash it, freeze-dry it, crush it and sieve it through an 80-120 mesh sieve. Use a composite enzyme obtained by mixing cellulase and pectinase with a mass ratio of 1:1. Perform enzymatic hydrolysis treatment at a pH value of 4.5 and a temperature of 45 °C for 60 min, then inactivate it in a 90 °C water bath for 5 min, and cool it to room temperature; S2. Use an ethanol solution with a mass fraction of 40%, add a 0.1 mol / L disodium hydrogen phosphate solution to adjust the pH value of the ethanol solution to 8.5. Control the mass-volume ratio of the enzymatically hydrolyzed material to the ethanol-alkali solution to be 1 g:10 mL. Heat it at a microwave power of 400 w and a temperature of 40 °C for 12 min (stop for 10 s every 30 s of heating) for extraction, and then centrifuge to separate to obtain the supernatant, which is the crude extract; S3. After the crude extract is intercepted and concentrated by a polyethersulfone membrane (ultrafiltration membrane) at 0.2 MPa, Houttuynia cordata Thunb. concentrated solution is obtained, and the volume of the Houttuynia cordata Thunb. concentrated solution is 10% of the volume of the crude extract; S4. The Houttuynia cordata Thunb. concentrated solution is pre-frozen at a vacuum of 10 Pa and -50 °C for 4 h, and then dried at -20 °C for 18 h to obtain Houttuynia cordata Thunb. extract.

[0027] After detection, the polysaccharide content in the obtained extract is 30.2 wt%, the flavonoid content is 5.1 wt%, the particle size distribution is uniform, and the solubility is good.

[0028] Example 4 This example provides a method for preparing Houttuynia cordata Thunb. extract, which includes the following steps: S1. Take fresh Houttuynia cordata Thunb., wash it, freeze-dry it, crush it and sieve it through an 80-120 mesh sieve. Use a composite enzyme obtained by mixing cellulase and pectinase with a mass ratio of 2:1. Perform enzymatic hydrolysis treatment at a pH value of 5.0 and a temperature of 45 °C for 50 min, then inactivate it in a 90 °C water bath for 5 min, and cool it to room temperature; S2. Use an ethanol solution with a mass fraction of 40%, add a 0.1 mol / L sodium bicarbonate solution to adjust the pH value of the ethanol solution to 8.7. Control the mass-volume ratio of the enzymatically hydrolyzed material to the ethanol-alkali solution to be 1 g:12 mL. Heat it at a microwave power of 500 w and a temperature of 45 °C for 13 min (stop for 10 s every 30 s of heating) for extraction, and then centrifuge to separate to obtain the supernatant, which is the crude extract; S3. After the crude extract is intercepted and concentrated by a polyethersulfone membrane (ultrafiltration membrane) at 0.2 MPa, a Houttuynia cordata concentrate is obtained, and the volume of the Houttuynia cordata concentrate is 15% of the volume of the crude extract; S4. The Houttuynia cordata concentrate is pre-frozen at -50 °C for 4 h under a vacuum of 10 Pa, and then dried at -20 °C for 18 h to obtain a Houttuynia cordata extract.

[0029] After detection, the polysaccharide content in the obtained extract is 30.5 wt%, the flavonoid content is 5.2 wt%, the particle size distribution is uniform, and the solubility is good.

[0030] Example 5 This example provides a preparation method of a Houttuynia cordata extract, including the following steps: S1. Take fresh Houttuynia cordata, wash it, freeze-dry it, crush it and sieve it through a 80-120 mesh sieve. Use a composite enzyme obtained by mixing cellulase and pectinase with a mass ratio of 3:1. After enzymatic hydrolysis at a pH value of 5.5 and a temperature of 50 °C for 40 min, inactivate it in a 90 °C water bath for 5 min, and cool it to room temperature; S2. Use an ethanol solution with a mass fraction of 50%, add a 0.1 mol / L sodium bicarbonate solution to adjust the pH value of the ethanol solution to 8.8, control the mass-to-volume ratio of the enzymatically hydrolyzed material to the ethanol-alkali solution to be 1 g:12 mL, heat it at a microwave power of 500 w and 40 °C for 13 min (stop for 10 s every 30 s of heating), carry out extraction, and then centrifuge and separate to obtain a supernatant, which is the crude extract; S3. After the crude extract is intercepted and concentrated by a polyethersulfone membrane (ultrafiltration membrane) at 0.2 MPa, a Houttuynia cordata concentrate is obtained, and the volume of the Houttuynia cordata concentrate is 10% of the volume of the crude extract; S4. The Houttuynia cordata concentrate is pre-frozen at -50 °C for 4 h under a vacuum of 10 Pa, and then dried at -20 °C for 18 h to obtain a Houttuynia cordata extract.

[0031] After detection, the polysaccharide content in the obtained extract is 31.5 wt%, the flavonoid content is 5.5 wt%, the particle size distribution is uniform, and the solubility is good.

[0032] Comparative Example 1 The difference from Example 1 is that in step S1, it is "take fresh Houttuynia cordata, wash it, freeze-dry it, crush it and sieve it through a 80-120 mesh sieve", and the other steps remain unchanged.

[0033] After detection, the polysaccharide content in the obtained extract is 21.4 wt%, and the flavonoid content is 3.2 wt%.

[0034] It can be seen from this that the synergistic action of cellulase and pectinase can effectively degrade cellulose and pectin in the plant cell wall, increase the release of cell contents, and thus greatly improve the extraction rates of polysaccharides and flavonoids.

[0035] Comparative Example 2 The difference from Example 1 is that in step S2, an equal amount of pure water is used to replace the ethanol-alkali solution, and the remaining steps remain unchanged.

[0036] After testing, the polysaccharide content in the obtained extract is 24.7 wt%, the flavonoid content is 3.9 wt%, there are many impurities, and the color is deep.

[0037] It can be seen from this that the ethanol-alkali system has good dissolution and protection effects on polysaccharides and flavonoids during the extraction process. The alkaline environment helps to destroy the cell wall structure and improve the leaching efficiency of the target components, while ethanol can selectively precipitate some impurity proteins and water-soluble macromolecules to improve the purity of the extract.

[0038] Comparative Example 3 The difference from Example 1 is that in step S2, an ethanol solution is used to replace the ethanol-alkali solution, and the remaining steps remain unchanged.

[0039] After testing, the polysaccharide content in the obtained extract is 26.1 wt%, the flavonoid content is 4.5 wt%, the color is relatively deep and it is prone to caking.

[0040] It can be seen from this that introducing an alkaline substance (such as sodium bicarbonate or disodium hydrogen phosphate) into the extraction solvent can effectively improve the dissolution efficiency of active ingredients. The reason may be that the weak alkaline environment helps to break the binding bonds between components such as polysaccharides and flavonoids and lignin and proteins in the plant cell wall, enhance the release ability of the target components, and at the same time inhibit the activity of some hydrolases to reduce the degradation of active ingredients.

[0041] Comparative Example 4 The difference from Example 1 is that in step S2, it is directly heated for 13 min without intermittent heating.

[0042] After testing, local coking occurred in some samples, the polysaccharide content decreased to 29.5 wt%, and the flavonoid was 4.7 wt%.

[0043] It can be seen from this that continuous heating easily leads to local overheating of the system, destroys the structure of thermosensitive active ingredients, reduces the extraction efficiency and product stability. In addition, local high temperature may also cause carbonization or degradation of some components, further affecting the quality of the extract. Therefore, using intermittent heating helps to achieve uniform temperature distribution, protect active ingredients, and improve the extraction effect and product quality.

[0044] Taking the houttuynia cordata extract prepared in Example 1 as an example, different amounts of clear water were added to prepare houttuynia cordata extraction solutions with different concentrations. Hereinafter, clear water, houttuynia cordata extraction solutions with concentrations of 1 / 30, 1 / 90, and 1 / 180 were used for hydroponics of lettuce with uniform growth, and they were respectively denoted as A1, B1, C1, and D1. Figures 1 - 2 It is the actual growth diagram of lettuce on the 7th day; Figures 3 - 4 It is the actual growth diagram of lettuce on the 15th day; Table 1 shows the specific values of the above-ground part length, root length, and fresh weight of lettuce in each group on the 15th day. Figures 5 - 7 It is the columnar analysis diagram of the above-ground part length, root length, and fresh weight of lettuce in different groups on the 15th day.

[0045] Table 1

[0046] In summary, it can be seen that there is no obvious change in the above-ground part length of the four groups of lettuce, but there are obvious changes in the root length and fresh weight. It shows that the houttuynia cordata extraction solution prepared in Example 1 of this application has an obvious root-promoting effect on lettuce and can increase the fresh weight of lettuce.

[0047] And from Table 1 and Figures 5 - 7 it can be seen that the root length ranking of each group is C1 > D1 > B1 > A1, that is, 1 / 90 houttuynia cordata extraction solution > 1 / 180 houttuynia cordata extraction solution > 1 / 30 houttuynia cordata extraction solution > clear water; the houttuynia cordata extraction solution has a certain promoting effect on the rooting of lettuce, and the effect of houttuynia cordata concentration 1 / 90 is better than that of houttuynia cordata concentration 1 / 180, which is better than that of houttuynia cordata concentration 1 / 30.

[0048] Comparative Example 5 This comparative example provides a cordyceps extraction solution (purchased from Gansu Yishengxiang Biotechnology Co., Ltd.). Different amounts of clear water were added to obtain cordyceps extraction solutions with different concentrations. Hereinafter, clear water, cordyceps extraction solutions with concentrations of 1 / 30, 1 / 90, and 1 / 180 were used for hydroponics of lettuce with uniform growth, and they were respectively denoted as A2, B2, C2, and D2.

[0049] Figures 8 - 9 It is the actual growth diagram of lettuce on the 7th day; Figures 10 - 11 It is the actual growth diagram of lettuce on the 15th day; Table 2 shows the specific values of the above-ground part length, root length, and fresh weight of lettuce in each group on the 15th day. Figures 12 - 14 It is the columnar analysis diagram of the above-ground part length, root length, and fresh weight of lettuce in different groups on the 15th day.

[0050] Table 2

[0051] From the above results, it can be seen that: there is no significant difference among the four groups in terms of the above-ground part length, root length, and fresh weight. That is, the cordyceps concentrated solution has no obvious promoting effect on the growth of lettuce.

[0052] Below, water, cordyceps extract at a concentration of 1 / 135, and houttuynia cordata extract at a concentration of 1 / 135 were used for hydroponics of wheat with uniform growth, denoted as A3, B3, and C3 respectively. Figure 15 It is the actual growth diagram of wheat on the 7th day; Figure 16 It is the actual growth diagram of wheat on the 12th day; Figure 17 It is the actual growth diagram of wheat on the 15th day; Figure 18 It is the actual growth control diagram of wheat on the 15th day; Table 3 shows the specific values of the upper root length, root length, and fresh weight of wheat in each group on the 15th day. Figures 19 - 21 It is the columnar analysis diagram of the upper root length, root length, and fresh weight of wheat in different groups on the 15th day.

[0053] Table 3

[0054] From the above results, it can be seen that there is no significant difference in the above-ground part length and fresh weight among the three groups.

[0055] There is a significant difference in the root length among the three groups, and A3 > C3 > B3, that is, water control > 1 / 135 houttuynia cordata extract > 1 / 135 cordyceps extract.

[0056] Neither the houttuynia cordata extract nor the cordyceps extract has an obvious promoting effect on the growth of wheat.

[0057] Comparative Example 6 In this comparative example, the houttuynia cordata extract prepared in Example 1 was added to 90-20-30 fertilizer (purchased from Jingmen Farmax Technology Co., Ltd., referring to the mass content of NPK respectively) at different concentrations, and divided into five groups according to Table 4, as follows.

[0058] Table 4

[0059] The above A4~E4 groups of fertilizers were used for hydroponics of lettuce with uniform growth. The growth conditions of lettuce corresponding to the A4~E4 groups of fertilizers on the 1st day were as Figure 22 shown; the growth conditions on the 9th day were as Figure 23 shown; the growth conditions on the 18th day were as Figure 24 shown; the growth conditions on the 22nd day were as Figure 25 shown; the growth conditions on the 25th day were as Figure 26 shown; the growth conditions on the 30th day were as Figure 27 shown; the statistical chart of the fresh weight of lettuce plants on the 30th day was as Figure 28 shown; the whole-plant weight of lettuce plants on the 30th day is shown in Table 5.

[0060] Table 5

[0061] In summary, there were significant differences in the fresh weight of the E4 group of plants compared with the other four groups; the fertilizer efficiency of the E4 group, that is, the conventional 90-20-30 formula fertilizer, was better than that of the 90-20-30 formula fertilizer containing Houttuynia cordata extract. Therefore, the Houttuynia cordata extract could not enhance the fertilizer efficiency of the conventional 90-20-30 formula.

[0062] Example 6 This example provides a water-soluble fertilizer based on Houttuynia cordata extract, which, by mass, includes the following components: 290 g of urea ammonium nitrate solution (concentration 30%, urea: ammonium nitrate molar ratio = 1:2); 740 g of the Houttuynia cordata extract prepared in Example 1 (particle size ≤ 100 mesh); 50 g of potassium dihydrogen phosphate; 20 g of potassium hydroxide aqueous solution (12 wt%); 3 g of Kathon; 10 g of 60% HEDP; 6 g of copper sulfate, 8 g of ferrous sulfate, 7 g of manganese sulfate, 1.2 g of ammonium molybdate, 8 g of zinc sulfate, 12 g of borax; The preparation of the water-soluble fertilizer based on Houttuynia cordata extract in this example includes the following steps: By mass, mix the urea ammonium nitrate solution and the hydroxyethylidene diphosphonic acid solution at 40 °C, then add potassium dihydrogen phosphate until dissolved, and then dropwise add the potassium hydroxide aqueous solution to the mixture. When the pH value of the mixture is 6.2, stop dropping; Subsequently, under the water bath condition of 30 °C, sequentially add the Houttuynia cordata extract, copper sulfate, ferrous sulfate, manganese sulfate, zinc sulfate, borax, and ammonium molybdate to it, and finally add Kathon. Stir in the dark and pass through a 100-mesh sieve to obtain the water-soluble fertilizer based on Houttuynia cordata extract.

[0063] After testing, the appearance of this fertilizer was clear and transparent, without precipitation, and it was stored stably at room temperature for 6 months without stratification or crystallization; and the polysaccharide retention rate ≥ 95%, and the flavonoid retention rate ≥ 90%.

[0064] Example 7 This example provides a water-soluble fertilizer based on Houttuynia cordata extract, which, by mass, includes the following components: 280 g of urea ammonium nitrate solution (concentration 30%, urea: ammonium nitrate molar ratio = 1:2.2); 760 g of the Houttuynia cordata extract prepared in Example 1 (particle size ≤ 100 mesh); 40 g of potassium dihydrogen phosphate; 25 g of potassium hydroxide aqueous solution (10 wt%); 5 g of Kathon; 8 g of 60% HEDP; 6 g of copper sulfate, 8 g of ferrous sulfate, 7 g of manganese sulfate, 1.2 g of ammonium molybdate, 8 g of zinc sulfate, 12 g of borax; The preparation of the water-soluble fertilizer based on Houttuynia cordata extract in this example includes the following steps: By mass parts, mix the urea ammonium nitrate solution and the hydroxyethylidene diphosphonic acid solution at 40 °C, add potassium dihydrogen phosphate until dissolved, then dropwise add an aqueous potassium hydroxide solution to the mixture. Stop adding when the pH value of the mixture reaches 6.0. Subsequently, under the water bath condition of 30 °C, successively add houttuynia cordata extract, copper sulfate, ferrous sulfate, manganese sulfate, zinc sulfate, borax and ammonium molybdate thereto, and finally add kaeson. Stir in the dark and pass through a 100-mesh sieve to obtain a water-soluble fertilizer based on houttuynia cordata extract.

[0065] Upon detection, the polysaccharide retention rate ≥ 94%, and the flavonoid retention rate ≥ 89%.

[0066] Example 8 This example provides a water-soluble fertilizer based on houttuynia cordata extract. By mass parts, it includes the following components: 300 g of urea ammonium nitrate solution (concentration 30%, molar ratio of urea:ammonium nitrate = 1:1.8); 720 g of houttuynia cordata extract prepared in Example 1 (particle size ≤ 100 mesh); 60 g of potassium dihydrogen phosphate; 15 g of aqueous potassium hydroxide solution (15 wt%); 2 g of kaeson; 12 g of 60% HEDP; 8 g of copper sulfate, 10 g of ferrous sulfate, 10 g of manganese sulfate, 1.5 g of ammonium molybdate, 10 g of zinc sulfate, 15 g of borax; The preparation of the water-soluble fertilizer based on houttuynia cordata extract in this example includes the following steps: By mass parts, mix the urea ammonium nitrate solution and the hydroxyethylidene diphosphonic acid solution at 40 °C, add potassium dihydrogen phosphate until dissolved, then dropwise add an aqueous potassium hydroxide solution to the mixture. Stop adding when the pH value of the mixture reaches 6.5. Subsequently, under the water bath condition of 30 °C, successively add houttuynia cordata extract, copper sulfate, ferrous sulfate, manganese sulfate, zinc sulfate, borax and ammonium molybdate thereto, and finally add kaeson. Stir in the dark and pass through a 100-mesh sieve to obtain a water-soluble fertilizer based on houttuynia cordata extract.

[0067] Upon detection, the polysaccharide retention rate ≥ 93%, and the flavonoid retention rate ≥ 88%.

[0068] Example 9 This example provides a water-soluble fertilizer based on houttuynia cordata extract. By mass parts, it includes the following components: 300 g of urea ammonium nitrate solution (concentration 28%, molar ratio of urea:ammonium nitrate = 1:2); 730 g of houttuynia cordata extract prepared in Example 1 (particle size ≤ 100 mesh); 55 g of potassium dihydrogen phosphate; 15 g of aqueous potassium hydroxide solution (15 wt%); 2 g of kaeson; 12 g of 60% HEDP; 8 g of copper sulfate, 10 g of ferrous sulfate, 10 g of manganese sulfate, 1.5 g of ammonium molybdate, 10 g of zinc sulfate, 15 g of borax; The preparation of the water-soluble fertilizer based on Houttuynia cordata Thunb. extract in this embodiment includes the following steps: By mass, mix the urea ammonium nitrate solution and the hydroxyethane diphosphonic acid solution at 40 °C, add potassium dihydrogen phosphate until dissolved, and then dropwise add potassium hydroxide aqueous solution to the mixture. When the pH value of the mixture is 6.1, stop dropping; Subsequently, under the water bath condition of 30 °C, sequentially add Houttuynia cordata Thunb. extract, copper sulfate, ferrous sulfate, manganese sulfate, zinc sulfate, borax and ammonium molybdate to it, and finally add Kathon. Stir in the dark and pass through a 100-mesh sieve to obtain the water-soluble fertilizer based on Houttuynia cordata Thunb. extract.

[0069] After testing, the polysaccharide retention rate ≥ 92%, and the flavonoid retention rate ≥ 87%.

[0070] Comparative Example 7 The difference from Example 6 is that the Houttuynia cordata Thunb. extract prepared in Example 1 is not added, and the preparation steps are modified adaptively, and the rest remains unchanged.

[0071] After testing: The phenomenon of stratification and / or crystallization appears after the fertilizer is stored at room temperature for 6 months.

[0072] Hydroponically cultivate the lettuce with uniform growth vigor using the fertilizer prepared in Example 6, the fertilizer prepared in Comparative Example 7, and the 90-20-30 fertilizer in Comparative Example 6; The whole-plant weight of the lettuce plants on the 30th day is shown in Table 6. A5 is the lettuce corresponding to the fertilizer in Example 6, B5 is the lettuce corresponding to the fertilizer in Comparative Example 7, and C5 is the lettuce corresponding to the 90-20-30 fertilizer in Comparative Example 6.

[0073] Table 6

[0074] It can be seen from Table 6 that there are significant differences in the whole-plant weights of the three groups of hydroponic lettuce corresponding to the fertilizers in Example 6, Comparative Example 6, and Comparative Example 7; The fertilizer efficiency of the fertilizer prepared in Example 6 is better than that of the existing 90-20-30 fertilizer, and better than that of the fertilizer in Comparative Example 7 without adding Houttuynia cordata Thunb. extract. This shows that: The water-soluble fertilizer prepared by the present invention has a significant promoting effect on the growth of lettuce.

[0075] The above are all the preferred embodiments of this application. The protection scope of this application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A method for preparing an extract of Houttuynia cordata, characterized in that, It includes the following steps: S1. After washing Houttuynia cordata, it is freeze-dried, pulverized and sieved through a 80-120 mesh sieve, and then enzymolysis treatment is carried out with a composite enzyme. S2. Using an ethanol-alkali solution as a solvent, the enzymolyzed material is extracted by microwave heating, and then centrifuged to obtain a crude extract. S3. After the crude extract is intercepted and concentrated by an ultrafiltration membrane, a Houttuynia cordata concentrate is obtained. S4. After the Houttuynia cordata concentrate is vacuum freeze-dried, a Houttuynia cordata extract is obtained.

2. The preparation method of the houttuynia cordata extract according to claim 1, characterized in that, In step S1, the composite enzyme is selected as cellulase and pectinase with a mass ratio of (1-3):

1. The enzymolysis process conditions include: pH value is 4.5-5.5, temperature is 45-50 °C, and treatment time is 40-60 min.

3. The preparation method of the houttuynia cordata extract according to claim 1, characterized in that, In step S2, the mass fraction of the ethanol solution is 40-55%, the alkaline substance is sodium bicarbonate or disodium hydrogen phosphate, and the pH value of the ethanol-alkali solution is 8.5-9.

4. The preparation method of the houttuynia cordata extract according to claim 3, characterized in that, In step S2, the conditions for microwave heating extraction include: microwave power is 400-600 W. The heating time is 12-15 min, the heating temperature is 40-50 °C, and the heating method is intermittent heating, stopping for 10 s every 30 s of heating. The mass-volume ratio of the enzymolyzed material to the ethanol-alkali solution is 1 g:10 mL-15 mL.

5. The preparation method of the houttuynia cordata extract according to claim 1, wherein, In S3, the volume of the Houttuynia cordata concentrate is 10-20% of the volume of the crude extract.

6. An extract of Houttuynia cordata, characterized in that, Prepared by the preparation method according to any one of claims 1-5, the mass content of polysaccharide in the Houttuynia cordata extract is not less than 30 wt%.

7. Application of the Houttuynia cordata extract according to claim 6 in a water-soluble fertilizer.

8. A water-soluble fertilizer based on Houttuynia cordata Thunb. extract, characterized in that, By mass parts, it includes the following components: 280-300 parts of urea ammonium nitrate solution; 720-760 parts of the Houttuynia cordata extract according to claim 6; 40-60 parts of potassium dihydrogen phosphate; 15-25 parts of potassium hydroxide aqueous solution; 2-5 parts of Kathon; 8-12 parts of hydroxyethylidene diphosphonic acid solution; 5-8 parts of copper sulfate; 5-10 parts of ferrous sulfate; 5-10 parts of manganese sulfate; 1-1.5 parts of ammonium molybdate; 5-10 parts of zinc sulfate; 10-15 parts of borax.

9. The water-soluble fertilizer based on houttuynia cordata extract according to claim 8, characterized in that, The mass concentration of the urea ammonium nitrate solution is 28-32%, and the urea ammonium nitrate solution contains ammonium nitrate and urea with a molar ratio of 1:1.8-2.

2. The particle size of the Houttuynia cordata extract is less than or equal to 100 mesh. The concentration of the potassium hydroxide aqueous solution is 10-15 wt%. The concentration of the hydroxyethylidene diphosphonic acid solution is 60 wt%.

10. A method for preparing a water-soluble fertilizer based on Houttuynia cordata Thunb. extract as claimed in claim 8 or 9, characterized in that, It includes the following steps: By mass parts, after mixing the urea ammonium nitrate solution and the hydroxyethylidene diphosphonic acid solution, potassium dihydrogen phosphate is added until dissolved, and then a potassium hydroxide aqueous solution is added dropwise to the mixed solution. When the pH value of the mixed solution is 6.0-6.5, the dropping is stopped. Subsequently, under the water bath condition of 25-30 °C, the Houttuynia cordata extract, copper sulfate, ferrous sulfate, manganese sulfate, zinc sulfate, borax and ammonium molybdate are added thereto in sequence, and finally Kathon is added. It is stirred in the dark and sieved through a 100 mesh sieve to prepare a water-soluble fertilizer based on the Houttuynia cordata extract.

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