An extraction method for epimedium extract

Abstract

The application discloses an extraction method for Epimedium extract, and relates to the technical field of traditional Chinese medicine extraction. The method comprises the following steps: firstly, freezing and crushing the raw material, and then adopting an ethanol solution to perform gradient temperature extraction, and through nonlinear decreasing solvent multiple, the energy consumption is reduced while the extraction rate is ensured; then, the extraction liquid is concentrated to a relative density of 1.10-1.15 and the residual ethanol is controlled to be 10%-15%, a metastable system with a specific alcohol-water ratio is constructed; after filtering out the fat-soluble impurities while hot, the effective components are directionally crystallized by using programmed temperature reduction, and finally, low-temperature washing and drying are performed to obtain the product. The method completely discards the complicated macroporous resin column chromatography process, effectively solves the problems of large solvent consumption, long production cycle and resin residue risk in the traditional technology, and is green and efficient, so that the cost is greatly reduced, and the high-purity and quality uniformity of the product are realized.

Description

Technical Field

[0001] This invention relates to the field of traditional Chinese medicine extraction technology, and in particular to a method for extracting Epimedium extract. Background Technology

[0002] Epimedium, a plant belonging to the genus Epimedium in the family Berberidaceae, is a traditional and precious Chinese medicinal herb. It possesses properties that tonify the kidneys and strengthen yang, fortify muscles and bones, and dispel wind and dampness. Its main active ingredients include icariin, citric acid, and total flavonoids. With the advancement of modern pharmacological research, Epimedium extracts have been widely used in pharmaceutical preparations, functional health foods, and cosmetic raw materials, exhibiting significant bioactivity, particularly in improving cardiovascular function, regulating the immune system, and combating osteoporosis. To meet the growing market demand and ensure the safety and efficacy of end products, developing an efficient, stable, and industrially suitable Epimedium extraction method that preserves active ingredients has become a key focus of technological research in this field.

[0003] A review of existing technologies reveals that common methods for producing Epimedium extract typically involve first pulverizing the Epimedium herb, then extracting it by heating and reflux with an ethanol solution. The extract is then filtered, concentrated under reduced pressure, and adsorbed onto a macroporous adsorption resin column. After washing with water to remove impurities, the extract is eluted with ethanol of varying concentrations. The eluent is collected, concentrated, and dried to obtain the final product. This technical approach represents a mainstream process commonly used in the industry, aiming to improve the purity of key components such as icariin in the final product through resin adsorption and desorption technology.

[0004] However, the existing extraction methods still have significant defects and shortcomings in actual industrial production. First, in the extraction stage, existing technologies typically use a fixed amount of solvent (e.g., 10 times the amount each time) in multiple reflux extractions, without adjusting the solvent amount according to the decreasing solute concentration in the medicinal material. This leads to a marginal decrease in subsequent extraction efficiency, resulting in solvent waste and a significant increase in energy consumption in the concentration stage. Second, in the purification stage, this method relies excessively on macroporous resin column chromatography, which not only increases the complexity of resin regeneration and cleaning, significantly extending the production cycle, but also because the resin adsorption process is often highly selective, easily causing the loss of other trace synergistic active ingredients in Epimedium while removing impurities. Furthermore, the risk of resin residue and high equipment operating costs limit its application in the pursuit of full-spectrum preservation and low-cost controlled products. Summary of the Invention

[0005] (a) Technical problems to be solved In view of the problems that existing epimedium extraction processes generally suffer from, such as high solvent consumption, high energy consumption for concentration, and long production cycles, potential resin residue risks, and loss of some synergistic active ingredients due to over-reliance on macroporous adsorption resin purification technology, this invention provides a method for preparing epimedium extract based on gradient countercurrent extraction and critical crystallization purification.

[0006] This method aims to improve solvent utilization efficiency through a nonlinear gradient extraction strategy and construct a metastable crystallization system by precisely controlling the density of the concentrate and the alcohol-water ratio. Without using macroporous resin, it achieves efficient enrichment and impurity separation of icariin and total flavonoids, and prepares a high-purity, low-cost and stable icariin extract.

[0007] (II) Technical Solution To solve the above-mentioned technical problems, the present invention adopts the following technical solution: This invention provides a method for extracting Epimedium extract, the method comprising the following steps: Step 1, Raw material pretreatment: Take Epimedium medicinal material, and after crushing, obtain coarse powder of medicinal material; Step 2, Gradient countercurrent extraction: Using an ethanol-water solution as a solvent, the crude powder of medicinal materials obtained in Step 1 is subjected to at least three heating and reflux extractions, and the amount of solvent added in subsequent extraction steps is less than the amount of solvent added in the previous extraction step. The extracts are combined and filtered to obtain the total extract. Step 3, Critical Concentration Control: The total extract obtained in Step 2 is concentrated under reduced pressure. By removing part of the solvent, the concentrate reaches a specific relative density range, while retaining a specific proportion of residual ethanol, forming a metastable alcohol-water system with icariin supersaturation. Step 4, temperature-controlled directional crystallization: The concentrated liquid obtained in step 3 is subjected to hot filtration to remove impurities, and then cooled according to a preset cooling rate under stirring to induce the crystallization of effective components. After standing to grow crystals, solid-liquid separation is performed and the precipitate is collected. Step 5, Washing and Drying: The precipitate collected in Step 4 is washed at low temperature, dried and then pulverized to obtain Epimedium extract.

[0008] Furthermore, in step 1, the process before pulverization also includes a freeze-embrittlement treatment: the Epimedium herb is frozen at -10°C to -20°C for 2-4 hours; the low temperature is used to destroy the plant cell wall structure, and the particle size of the coarse powder of the pulverized herb is controlled to be 20-40 mesh to facilitate solvent penetration.

[0009] Further, in step 2, the volume fraction of the ethanol-water solution is 50%-80%; the gradient countercurrent extraction specifically includes three extractions, with the solvents used in the three extractions being 8-10 times, 5-7 times, and 2-4 times the mass of the crude herbal powder, respectively. A "variable temperature extraction" strategy is preferably adopted, with the specific process parameters as follows: First extraction: Add 8 times the volume of 70% ethanol aqueous solution, extract at 80-85℃, and extract for 1.5-2.0 hours; Second extraction: Add 6 times the volume of 70% ethanol aqueous solution, extract at 70-75℃, and extract for 1.0-1.5 hours; Third extraction: Add 3 times the amount of 70% ethanol aqueous solution, extract at 60-65℃, and extract for 0.5-1.0 hours.

[0010] This gradient temperature strategy aims to balance extraction rate and impurity dissolution rate while reducing energy consumption.

[0011] Further, in step 3, the vacuum degree of the reduced pressure condition is -0.06 MPa to -0.09 MPa, and the concentration temperature is 50-60℃; the specific relative density range refers to the relative density of the concentrate controlled at 1.10-1.15 under the measurement condition of 60℃; the specific proportion of residual ethanol refers to the volume fraction of ethanol in the concentrate maintained at 10%-15% by monitoring the amount of condensate or online detection. This condition is a critical point to ensure the purity of subsequent crystallization.

[0012] Furthermore, in step 4, the thermal filtration for impurity removal refers to removing fat-soluble resins, colloids, and waxy impurities that precipitate due to concentration by passing the concentrate through a 200-300 mesh filter or a centrifuge while maintaining the temperature of the concentrate above 50°C, in order to prevent them from encapsulating the effective ingredients.

[0013] Further, in step 4, the specific operation of the variable-temperature directional crystallization is as follows: the concentrated solution after hot filtration is transferred into a crystallization tank, the stirrer is turned on, the speed is controlled at 30-60 rpm, the cooling rate is controlled at 3-6℃ / hour, until the system temperature drops to 4-8℃, and the crystals are kept at this temperature for 24-48 hours. The crystal nucleus formation rate is controlled by the programmed cooling to avoid co-precipitation of impurities.

[0014] Furthermore, in step 5, the low-temperature washing specifically refers to: using purified water at a temperature of 0-4℃ to spray and wash the precipitate, with the amount of purified water being 1.0-2.0 times the wet weight of the precipitate, and the washing time being controlled within 3-5 minutes, in order to quickly remove water-soluble mother liquor impurities adhering to the crystal surface.

[0015] Furthermore, in step 5, the drying is carried out by vacuum freeze drying or vacuum drying under reduced pressure; wherein the temperature of vacuum drying under reduced pressure is not higher than 60°C, and the vacuum degree is controlled below -0.08MPa until the product moisture content is lower than 5%.

[0016] Furthermore, the epimedium extract prepared by the above method has an epimedin content of 60%-98% by mass and does not contain macroporous adsorption resin residue.

[0017] Compared with the prior art, the beneficial effects of the present invention are: Unlike existing technologies that use a fixed amount of solvent (e.g., 10 times the amount throughout the extraction process), this invention innovatively introduces a nonlinear solvent reduction and variable temperature extraction strategy. By using a high volume and high temperature in the early stages of extraction to quickly establish a concentration gradient, and then significantly reducing the amount of solvent and lowering the temperature in the later stages, this not only conforms to the objective law that the concentration of solutes in the cells of medicinal materials decreases with the number of extractions, but also effectively avoids the heating of ineffective solvents and subsequent concentration consumption, resulting in an overall solvent evaporation saving of more than 30%. At the same time, the stepped cooling strategy effectively inhibits the dissolution of lipid-soluble impurities such as chlorophyll and waxes in the later stages of extraction, reducing the load on subsequent separation and purification from the source, and achieving the dual benefits of energy saving, consumption reduction, and impurity control.

[0018] This invention constructs a metastable crystallization system specifically for icariin and total flavonoids by precisely controlling the relative density and residual ethanol ratio of the concentrate. Physical separation is achieved by utilizing the differences in solubility of different components in a specific alcohol-water system. This method successfully eliminates the cumbersome resin column chromatography process, directly eliminating the discharge of acid and alkali wastewater during resin regeneration and the potential risk of residual organic resin in the final product. It significantly shortens the production cycle and greatly reduces equipment investment and operating costs. Simultaneously, this physical purification process is gentle, maximizing the retention of the original synergistic active ingredients in the medicinal materials and avoiding selective loss caused by resin adsorption.

[0019] This invention addresses the shortcomings of traditional simple static precipitation methods, which suffer from the difficulty in controlling the co-precipitation of active ingredients and impurities. This application employs programmed cooling crystallization and low-temperature rinsing techniques to achieve a transformation from disordered precipitation to ordered crystallization. By standardizing and controlling key process parameters (such as critical density 1.10-1.15, residual ethanol 10%-15%, and crystallization temperature 4-8℃), a high degree of consistency in product quality between batches is ensured. The purity of icariin in the final product can be stably adjusted between 60% and 98%. This green, low-carbon, and parameter-controllable production process perfectly meets the stringent requirements of the modern plant extract industry for standardization, high purity, and clean production. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the process flow steps of the present invention; Figure 2 This is a schematic diagram of the gradient solvent reduction and temperature-varying extraction model of the present invention. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be noted that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0022] Example 1 This embodiment provides a standardized method for preparing epimedium extract, with the target product being an extract containing ≥60% icariin. The specific steps are as follows: Step 1, Raw material pretreatment: Take 100 kg of dried Epimedium medicinal material, place it in a freezer at -15℃ for 3 hours to freeze and embrittle it, take it out and quickly crush it through a pulverizer, and pass it through a 30-mesh sieve to obtain coarse powder of the medicinal material.

[0023] Step 2, Gradient countercurrent temperature-varying extraction: Three-stage gradient temperature extraction was performed using a 70% (v / v) ethanol aqueous solution as the solvent. (1) First extraction: Add solvent in 8 times the weight of the medicinal material (800kg), heat to 85℃, reflux for 2.0 hours, and filter while hot; (2) Second extraction: Add solvent of 6 times the weight of the medicinal material (600 kg) to the residue, heat to 75℃, reflux for 1.5 hours, and filter; (3) Third extraction: Add solvent of 3 times the weight of the medicinal material (300kg) to the residue, heat to 65℃, reflux for 0.5 hours, and filter.

[0024] The three filtrates were combined to obtain the total extract. The total solvent used here was 1700 kg (a 43% saving compared to the traditional 3000 kg).

[0025] Step 3, Critical Concentration Control: The total extract was pumped into a vacuum concentration tank and concentrated under a vacuum of -0.08 MPa and a temperature of 55°C. Concentration was stopped when the relative density of the concentrate reached 1.12 at 60°C and the calculated residual ethanol volume fraction was approximately 12%, using an online density meter and condensate recovery rate monitoring. This allowed the system to form a metastable state.

[0026] Step 4: Temperature-dependent directional crystallization: Maintain the concentrated solution temperature at 55℃ and filter it through a 200-mesh vibrating screen to remove the precipitated dark brown resinous and waxy impurities. Transfer the filtrate to a crystallization tank, start stirring (45 rpm), and set the cooling rate to 4℃ / hour. When the temperature drops to 6℃, stop cooling and let it stand at a constant temperature for 36 hours to allow crystals to grow. At this point, a large number of pale yellow needle-like crystals will be visible precipitating at the bottom of the container.

[0027] Step 5, Washing and Drying: Remove the upper layer of dark brown mother liquor and collect the precipitate at the bottom. Quickly spray and wash the surface of the precipitate with purified water at 4°C (1.5 times the wet weight of the precipitate) to remove the attached mother liquor. Place the wet precipitate in a vacuum drying oven and dry it to constant weight at -0.08 MPa and 50°C. Grind it and pass it through an 80-mesh sieve to obtain 2.8 kg of Epimedium extract.

[0028] HPLC analysis showed that the finished product contained 72.5% icariin and 88.4% total flavonoids, with no macroporous resin residue.

[0029] Example 2 This example aims to prepare a high-purity (>90%) icariin product. The main difference from Example 1 lies in the fine adjustment of the concentration density and crystallization conditions. The specific steps are as follows: Pretreatment and extraction: The raw material processing and gradient extraction process are the same as in Example 1 (8 times / 85℃, 6 times / 75℃, 3 times / 65℃).

[0030] Critical concentration: Concentrate to a relative density of 1.15 (measured at 60°C), with the residual volume fraction of ethanol controlled at 10% (to reduce alcohol content and decrease glycoside solubility).

[0031] Variable temperature crystallization: After hot filtration, adjust the stirring speed to 30 rpm (low speed), adjust the cooling rate to 3℃ / hour (slow speed to cultivate large crystals), cool down to 4℃, and maintain constant temperature for crystal growth for 48 hours.

[0032] Post-processing: Wash with twice the amount of purified water at 0℃ and freeze-dry under vacuum.

[0033] The final yield was 2.1 kg of pale yellow crystalline powder. Testing revealed that the icariin content was 95.2% and the total flavonoid content was 98.1%.

[0034] Example 3 This embodiment simulates large-scale, low-cost production, and the parameters are taken from the lower limit of the range.

[0035] Pretreatment: Freeze for 2 hours, then pass through a 20-mesh sieve.

[0036] Extraction: Gradient solvents were used at 8x, 5x, and 2x concentrations. Temperatures were 80℃, 70℃, and 60℃.

[0037] Concentration: Concentrated to a relative density of 1.10, with a residual ethanol volume fraction of 15%.

[0038] Crystallization: Cooling rate 6℃ / hour, cool to 8℃, crystallize for 24 hours.

[0039] Post-treatment: Wash with 1 part water at 4℃, and dry under reduced pressure at 60℃.

[0040] The final yield was 3.1 kg of yellowish-brown powder. Testing showed that the icariin content was 61.3%, meeting the basic requirements for standardized extracts, and the production cycle was the shortest.

[0041] Comparative Example 1 To verify the advancement of this invention, a comparison was made using the process described in CN102920743B (prior reference document): Extraction: 100 kg of medicinal materials were extracted three times with 70% ethanol, using 10 times the amount of ethanol each time, for 2 hours each time, at a uniform temperature of 80℃. The total solvent used was 3000 kg.

[0042] Concentration: Concentrate until there is no alcohol taste (relative density approximately 1.05).

[0043] Purification: Load the sample into the prepared D101 macroporous adsorption resin column, wash with water first, and then elute with 70% ethanol.

[0044] Drying: After recovering ethanol from the eluent, concentrate and dry.

[0045] Results: 2.4 kg of extract was obtained, with an icariin content of 65.1%. Although the purity was acceptable, the solvent consumption was 76% higher than in Example 1, and the resin treatment step was added, increasing the total time by approximately 12 hours. Trace amounts of styrene residues were also detected.

[0046] Comparative Example 2 To verify the necessity of the "gradient extraction" and "critical parameters" of this invention: Extraction: Use 6 times the amount for each of the 3 extractions, and maintain a uniform temperature of 80℃.

[0047] Concentration: Concentrate to a relative density of 1.25 (too high, it will become a paste) or a relative density of 1.05 (too low, it will be too thin).

[0048] Sedimentation: Allow to cool naturally.

[0049] result: If concentrated to 1.25: the material becomes a paste, crystals cannot be precipitated, and only total extract can be obtained, with icariin content of only 8.5% (impurities are not removed).

[0050] If concentrated to 1.05: very little precipitate, yield less than 0.5%.

[0051] This demonstrates that the density range (1.10-1.15) defined in the claims of this invention is key to achieving "self-crystallization purification".

[0052] Comparison table of results data: Results analysis: As shown in the table above, the embodiments of the present invention significantly reduce solvent consumption and energy consumption, shorten the production cycle, and completely avoid the risk of resin residue while ensuring product purity (even higher than that of the traditional resin method). Comparative Example 2 confirms that the core parameters (density and gradient) of the present invention have outstanding substantive characteristics.

Claims

1. A method for extracting Epimedium extract, characterized in that, The method includes the following steps: Step 1, Raw material pretreatment: Take Epimedium medicinal material, and after crushing, obtain coarse powder of medicinal material; Step 2, Gradient countercurrent extraction: Using an ethanol-water solution as a solvent, the crude powder of medicinal materials obtained in Step 1 is subjected to at least three heating and reflux extractions, and the amount of solvent added in subsequent extraction steps is less than the amount of solvent added in the previous extraction step. The extracts are combined and filtered to obtain the total extract. Step 3, Critical Concentration Control: The total extract obtained in Step 2 is concentrated under reduced pressure. By removing part of the solvent, the concentrate reaches a specific relative density range, while retaining a specific proportion of residual ethanol, forming a metastable alcohol-water system with icariin supersaturation. Step 4, temperature-controlled directional crystallization: The concentrated liquid obtained in step 3 is subjected to hot filtration to remove impurities, and then cooled according to a preset cooling rate under stirring to induce the crystallization of effective components. After standing to grow crystals, solid-liquid separation is performed and the precipitate is collected. Step 5, Washing and Drying: The precipitate collected in Step 4 is washed at low temperature, dried and then pulverized to obtain Epimedium extract.

2. The method for extracting Epimedium extract according to claim 1, characterized in that, In step 1, the process before pulverization also includes a freeze-brittle treatment: the Epimedium herb is frozen at -10°C to -20°C for 2-4 hours; the coarse powder of the herb after pulverization has a particle size of 20-40 mesh.

3. The method for extracting Epimedium extract according to claim 1, characterized in that, In step 2, the volume fraction of the ethanol aqueous solution is 50%-80%; the gradient countercurrent extraction specifically includes three extractions, and the mass of the solvent used in the three extractions is 8-10 times, 5-7 times and 2-4 times the mass of the crude medicinal powder, respectively.

4. The method for extracting Epimedium extract according to claim 3, characterized in that, In step 2, the gradient countercurrent extraction employs a "variable temperature extraction" strategy, with the specific process parameters as follows: First extraction: Add 8 times the volume of 70% ethanol aqueous solution, extract at 80-85℃, and extract for 1.5-2.0 hours; Second extraction: Add 6 times the volume of 70% ethanol aqueous solution, extract at 70-75℃, and extract for 1.0-1.5 hours; Third extraction: Add 3 times the amount of 70% ethanol aqueous solution, extract at 60-65℃, and extract for 0.5-1.0 hours.

5. The method for extracting Epimedium extract according to claim 1, characterized in that, In step 3, the vacuum degree of the reduced pressure condition is -0.06MPa to -0.09MPa, and the concentration temperature is 50-60℃; The specific relative density range refers to the relative density of the concentrate being controlled between 1.10 and 1.15 under the measurement conditions of 60°C. The specific proportion of residual ethanol refers to maintaining the volume fraction of ethanol in the concentrate at 10%-15%.

6. The method for extracting Epimedium extract according to claim 1, characterized in that, In step 4, the thermal filtration for impurity removal refers to removing precipitated fat-soluble resins, colloids, and waxy impurities by passing the concentrate through a 200-300 mesh filter or a centrifuge while maintaining the temperature of the concentrate above 50°C.

7. The method for extracting Epimedium extract according to claim 1, characterized in that, In step 4, the specific operation of the variable temperature directional crystallization is as follows: the concentrated liquid after hot filtration is transferred into the crystallization tank, the stirring paddle is turned on, the speed is controlled at 30-60 rpm, the cooling rate is controlled at 3-6℃ / hour, until the system temperature drops to 4-8℃, and the crystals are kept at this temperature for 24-48 hours.

8. The method for extracting Epimedium extract according to claim 1, characterized in that, In step 5, the low-temperature washing specifically refers to: using purified water at a temperature of 0-4℃ to spray and wash the precipitate, with the amount of purified water being 1.0-2.0 times the wet weight of the precipitate, and the washing time being controlled within 3-5 minutes.

9. The method for extracting Epimedium extract according to claim 1, characterized in that, In step 5, the drying is performed using vacuum freeze drying or reduced pressure vacuum drying; The temperature of vacuum drying is not higher than 60℃, and the vacuum degree is controlled below -0.08MPa until the product moisture content is lower than 5%.

10. The Epimedium extract prepared according to any one of claims 1 to 9, characterized in that, The extract contains 60%-98% icariin by mass and contains no macroporous adsorption resin residue.

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