Method for extracting swertia bimaculata extract through ionic liquid microwave synergism

Abstract

The invention belongs to the field of plant extracts, and particularly relates to a method for extracting a swertia bimaculata extract through ionic liquid microwave synergism. Aiming at the problems of low extraction efficiency, large organic solvent dosage, long time, environmental pollution and the like of the traditional extraction methods such as organic solvent extraction, ultrasonic-assisted extraction and the like, the invention creatively adopts two times of ultrasonic extraction, improves the extraction rate by using the ionic liquid and calcium carbonate, has the advantages of high extraction efficiency, short time, environmental protection, low cost and the like, and is simple in process and easy to implement. The quality of the extract is high, and the industrial value is higher.

Description

Technical Field

[0001] The invention belongs to the field of plant extracts, and particularly relates to a method for extracting Swertia japonica extracts by ionic liquid and microwave synergy. Background Art

[0002] Swertia bimaculata is a medicinal plant of the genus Swertia in the Gentianaceae family, widely distributed in the high-altitude areas of southwest China. Its whole plant or roots are commonly used in traditional Chinese medicine for its efficacy in clearing heat and detoxifying, promoting dampness and relieving jaundice. Based on actual folk experience and extensive literature, drugs made from Swertia plants and their extracts have unique clinical efficacy for various inflammatory conditions, such as pharyngitis, tonsillitis, and conjunctivitis. Its main active ingredients include iridoids such as swertiamarin and gentiopicroside, flavonoids such as mangiferin and isoorientin, as well as total triterpenes and total phenolic acids. Modern medical research has confirmed that swertiamarin exhibits significant pharmacological activity in anti-inflammatory, antioxidant, and anti-apoptotic aspects, and has potential therapeutic value for common clinical diseases such as diabetes and hyperlipidemia.

[0003] Traditional methods for extracting the active ingredients of Swertia japonica mainly include organic solvent extraction, water extraction, and ultrasound-assisted extraction. However, these methods generally suffer from low extraction efficiency, large amounts of organic solvents, long extraction times, and environmental pollution. For example, Chinese patent CN200410022719.1 discloses a technical solution using ethanol cold extraction, which involves extracting the extracts multiple times by combining the extracts and then recovering the ethanol under reduced pressure to obtain an extract. Although this method is simple to operate, it has low extraction efficiency, and the use of ethanol poses a flammable and explosive risk. The subsequent recovery process is complex and energy-intensive. Chinese patent CN200510110396.6 mainly discloses the use of 75% aqueous ethanol to extract Swertia japonica glycosides in batches, combining the extracts and concentrating them on a column. Although this method improves the yield of the target ingredient, it still relies on a large amount of organic solvent, and the concentration process can easily lead to the degradation of heat-sensitive components. In addition, Chinese patent CN202110182011.6 is a multi-step method that combines water extraction, sodium chloride solution high-pressure extraction and ethanol extraction. Although it improves the extraction efficiency to a certain extent, the process is complicated, the operation time is long, and organic solvents are still required, which is less environmentally friendly.

[0004] Ionic liquids are organic salts composed of anions and cations that are liquid at low temperatures. They are non-volatile, have high thermal stability, a wide liquid range, and are highly designable. Their unique physical and chemical properties enable them to efficiently transmit and absorb microwave energy, while also having good miscibility with water and organic solvents. In the field of plant extraction, ionic liquids can be used as green solvents to replace traditional organic solvents, significantly improving extraction efficiency and reducing environmental pollution. However, there are currently no reports on the research on the ionic liquid microwave synergistic extraction of active ingredients from Swertia japonica. In the existing technology, the application of ionic liquids in plant extraction is mostly focused on the extraction of a single component, while optimization research on the synergistic extraction of multiple components from Swertia japonica is still blank. Therefore, the development of an efficient, environmentally friendly, and easy-to-operate ionic liquid microwave synergistic extraction method is of great significance for the comprehensive utilization of Swertia japonica resources and the modernization of traditional Chinese medicine. Summary of the Invention

[0005] The present invention provides a method for extracting Swertia japonica extract by ionic liquid and microwave synergistically, comprising:

[0006] S1. Drying the Swertia japonica, then crushing and sieving the Swertia japonica to obtain Swertia japonica powder;

[0007] S2, mixing the Swertia japonica powder and a solvent, then adding an ionic liquid, extracting under ultrasonic conditions for 20-30 minutes, and collecting a first filtrate and a first filter residue;

[0008] S3, mixing the first filter residue and the solvent, adding a cell wall disruptor, performing a second ultrasonic extraction, and collecting a second filtrate and a second filter residue;

[0009] S4. Combining the first filtrate and the second filtrate, then centrifuging, collecting the supernatant, and concentrating to obtain the Swertia japonica extract.

[0010] As an implementable case, the drying process includes oven drying or natural sun drying.

[0011] Furthermore, the drying temperature is 50-60°C.

[0012] As an implementable case, the mesh size of the crushing and screening is 20-100 meshes.

[0013] Furthermore, the mesh size of the crushed and sieved particles is 40-60 meshes.

[0014] In the present invention, the scutellaria baicalensis is first dried at 50-60°C or naturally sun-dried to remove moisture from the raw material. The dried scutellaria baicalensis raw material is easier to store and process, and can effectively prevent the growth and reproduction of microorganisms, extend the shelf life of the raw material, and ensure the smooth progress of the subsequent extraction process. At the same time, the dried scutellaria baicalensis is crushed to a 40-60 mesh sieve to increase the specific surface area of ​​the raw material. The smaller particle size helps to increase the contact area between the active ingredients and the extraction solvent, making the active ingredients easier to dissolve, thereby improving the extraction efficiency of the scutellaria baicalensis extract.

[0015] As an implementable example, the solvent includes ethanol or water.

[0016] Furthermore, the solvent is water.

[0017] As an practicable case, the mass ratio of the Swertia japonica powder to the solvent is 1:(10-20).

[0018] As an implementable example, the ionic liquid includes 1-butyl-3-methylimidazolium bromide ([Bmim]Br).

[0019] The present invention selects the ionic liquid 1-butyl-3-methylimidazolium bromide as one of the extraction raw materials. It has good solubility for active ingredients such as picroside, gentiopicroside, and total flavonoids in Swertia japonica. The special cationic structure of 1-butyl-3-methylimidazolium bromide can form a specific interaction with the molecules of the active ingredients, making it easier for these active ingredients to dissolve from the plant cells of Swertia japonica into the ionic liquid-water solution, thereby improving the extraction efficiency. 1-butyl-3-methylimidazolium bromide [Bmim]Br is miscible with water in any proportion, and a small amount can effectively dissolve the target dissolution product. In addition, compared with traditional organic solvents, the ionic liquid [Bmim]Br has extremely low volatility and is not easily lost during the extraction process, unlike organic solvents such as ethanol. This not only reduces the solvent loss cost during the extraction process, but also avoids the safety hazards and environmental pollution problems caused by solvent volatilization.

[0020] As an practicable example, the usage amount of the ionic liquid is 20-30% of the total mass of the Swertia japonica powder and the solvent.

[0021] As an implementable case, the power of the ultrasonic extraction is 280-350W.

[0022] As an practicable case, the temperature of the ultrasonic extraction is 60-70°C.

[0023] As an implementable case, in the step S3, the mass ratio of the first filter residue to the solvent is 1:(5-10).

[0024] As an implementable example, the cell wall disrupting agent includes calcium carbonate or silicon dioxide.

[0025] Furthermore, the cell wall destroyer is calcium carbonate.

[0026] During the first extraction process, some acidic components may dissolve into the extract, causing the solution to become acidic. Calcium carbonate is a weakly alkaline substance that can react with acidic substances to neutralize and adjust the pH value of the extract to be close to neutral or weakly alkaline, which helps maintain the stability of the extraction system and avoids the adverse effects of the acidic environment on the stability of the active ingredients. At the same time, calcium carbonate is a relatively hard solid particle with a Mohs hardness of about 3. During the extraction process, when it comes into contact with the cell wall of Swertia japonica, it will produce mechanical grinding and friction on the cell wall, which can destroy the structure of the cell wall and make it loose and porous, thereby increasing the permeability of the cell wall and making it easier to release the active ingredients in the cell.

[0027] As an implementable example, the usage amount of the cell wall destroyer is 5-10% of the total mass of the first filter residue and the solvent.

[0028] As an implementable case, the ultrasonic power in the second ultrasonic extraction is 280-350W.

[0029] As an implementable case, the temperature of the second ultrasonic extraction is 40-50°C.

[0030] The first extraction in the present invention is performed at a temperature of 60-70°C. Under high temperature conditions, the ionic liquid can fully utilize its good miscibility with water and microwave absorption and transmission capabilities, synergizing with the cavitation effect of ultrasound to efficiently transfer energy into plant cells, promoting cell rupture and the release of active ingredients. When the temperature is lowered to 40-50°C during the second ultrasonic extraction, the ionic liquid still maintains its unique solvation properties, forming a stable association structure with the remaining active ingredients, further improving its solubility and stability in water, facilitating the full extraction of the active ingredients remaining after the first extraction, while avoiding changes in certain properties of the ionic liquid or degradation of the active ingredients caused by excessively high temperatures.

[0031] Beneficial effects

[0032] (1) The present invention innovatively adopts ionic liquid ([Bmim]Br) microwave synergistic extraction technology and organically combines it with two ultrasonic extractions. When extracting key active ingredients such as scutellaria baicalensis, gentiopicroside, and total flavonoids, the extraction rate is significantly improved compared with traditional single solvent extraction or ordinary ultrasonic extraction methods.

[0033] (2) The entire extraction process of the present invention is highly efficient, starting from the pretreatment stage of the raw materials, and then undergoing two ultrasonic extractions, filtration, centrifugation, and concentration, to ultimately obtain a high-purity Swertia japonica extract. The entire process requires much less time than traditional methods. Traditional processes may require several hours or even dozens of hours of extraction time, but after optimizing the parameters of each step, the present invention can complete the entire extraction process in a shorter time, greatly shortening the production cycle, effectively improving production efficiency, and meeting the strict time cost requirements of large-scale industrial production.

[0034] (3) The present invention uses distilled water as the primary extraction agent. This avoids the use of large amounts of organic solvents, such as ethanol and acetone, commonly found in traditional processes. These solvents can remain in the extract during the extraction process, potentially posing a health hazard to humans. Their volatility can also lead to environmental pollution and safety risks. Furthermore, ionic liquids are inherently non-volatile or extremely low-volatility, eliminating the generation of flammable or explosive gases during use. This ensures a safe and reliable operation, minimizing potential safety risks.

[0035] (IV) The present invention uses ionic liquids as key extraction aids, and ionic liquids have the significant advantage of being recyclable. After the extraction process is completed, the ionic liquid can be separated and recovered from the extraction waste liquid through simple physical or chemical methods such as distillation and precipitation, and reused in a new extraction cycle, which greatly reduces production costs. In addition, the extraction process mainly relies on microwave and ultrasonic equipment, and the requirements for the material and complexity of the equipment are relatively low. Unlike traditional organic solvent extraction, there is no need for high-end corrosion-resistant and pressure-resistant equipment, which further saves equipment investment costs and improves the economy and feasibility of the present invention in practical applications.

[0036] (5) The extraction method provided by this invention is highly innovative, filling a gap in the field of ionic liquid-microwave synergistic extraction of active ingredients from Swertia japonica. Furthermore, this method possesses excellent universality and scalability, and its core technical concepts can be applied to the extraction of active ingredients from other medicinal plants after appropriate adjustments and optimization. DETAILED DESCRIPTION

[0037] Example 1

[0038] This example provides a method for extracting Swertia japonica extract by ionic liquid and microwave assisted extraction, which specifically comprises the following steps:

[0039] S1. Selecting and removing impurities from Swertia japonica by air separation, drying at 55° C. to constant weight, then crushing and sieving through a 40-mesh sieve to obtain Swertia japonica powder;

[0040] S2. Mixing Swertia japonica powder and distilled water in a mass ratio of 1:10, and then adding ionic liquid 1-butyl-3-methylimidazolium bromide, wherein the amount of the ionic liquid added is 20% of the total mass of the Swertia japonica powder and distilled water; then extracting under ultrasonic conditions at 65° C. and 300 W power for 20 minutes, and collecting a first filtrate and a first filter residue;

[0041] S3, mixing the first filter residue and distilled water in a mass ratio of 1:5, and adding calcium carbonate, wherein the amount of calcium carbonate added is 5% of the total mass of the first filter residue and distilled water; then performing a second ultrasonic extraction under ultrasonic conditions at 50° C. and a power of 300 W for 10 minutes, and collecting a second filtrate and a second filter residue;

[0042] S4. Combine the first filtrate and the second filtrate, then centrifuge, collect the supernatant, and concentrate to 15% of the supernatant liquid volume fraction to obtain the Swertia japonica extract; freeze-dry according to actual use needs.

[0043] Example 2

[0044] This example provides a method for extracting Swertia japonica extract by ionic liquid and microwave assisted extraction, which specifically comprises the following steps:

[0045] S1. Selecting and removing impurities from Swertia japonica by air separation, drying at 60° C. to constant weight, then crushing and sieving through a 60-mesh sieve to obtain Swertia japonica powder;

[0046] S2. Mixing Swertia japonica powder and distilled water in a mass ratio of 1:15, and then adding ionic liquid 1-butyl-3-methylimidazolium bromide, wherein the amount of the ionic liquid added is 30% of the total mass of the Swertia japonica powder and distilled water; then extracting under ultrasonic conditions at 70° C. and 300 W power for 30 minutes, and collecting a first filtrate and a first filter residue;

[0047] S3, mixing the first filter residue and distilled water in a mass ratio of 1:5, and adding calcium carbonate, wherein the amount of calcium carbonate added is 5% of the total mass of the first filter residue and distilled water; then performing a second ultrasonic extraction under ultrasonic conditions at 50° C. and a power of 300 W for 10 minutes, and collecting a second filtrate and a second filter residue;

[0048] S4. Combine the first filtrate and the second filtrate, then centrifuge, collect the supernatant, and concentrate to 15% of the supernatant liquid volume fraction to obtain the Swertia japonica extract; freeze-dry according to actual use needs.

[0049] Example 3

[0050] The specific implementation of this example is the same as that of Example 1, except that no ionic liquid is used in the extraction process.

[0051] Example 4

[0052] The specific implementation of this example is the same as that of Example 1, except that the amount of the ionic liquid added is 10% of the total mass of the Swertia japonica powder and distilled water.

[0053] Example 5

[0054] The specific implementation of this example is the same as that of Example 1, except that the amount of the ionic liquid added is 30% of the total mass of the Swertia japonica powder and distilled water.

[0055] Example 6

[0056] The specific implementation of this example is the same as that of Example 1, except that the amount of the ionic liquid added is 40% of the total mass of the Swertia japonica powder and distilled water.

[0057] Example 7

[0058] The specific implementation of this example is the same as that of Example 1, except that the amount of the ionic liquid added is 50% of the total mass of the Swertia japonica powder and distilled water.

[0059] Example 8

[0060] The specific implementation of this example is the same as that of Example 1, except that the extraction temperature in step S2 is 30°C.

[0061] Example 9

[0062] The specific implementation of this example is the same as that of Example 1, except that the extraction temperature in step S2 is 40°C.

[0063] Example 10

[0064] The specific implementation of this example is the same as that of Example 1, except that the extraction temperature in step S2 is 50°C.

[0065] Example 11

[0066] The specific implementation of this example is the same as that of Example 1, except that the extraction temperature in step S2 is 60°C.

[0067] Example 12

[0068] The specific implementation of this example is the same as that of Example 1, except that the extraction temperature in step S2 is 70°C.

[0069] Example 13

[0070] The specific implementation of this example is the same as that of Example 1, except that the extraction temperature in step S2 is 80°C.

[0071] Performance evaluation

[0072] 1. Extraction rate test

[0073] Test object: Swertia japonica extract prepared in Examples 1-13.

[0074] Test item: Test the extraction rate of Swertia japonica extract, the calculation method is: extraction rate (%) = (W E / W X )×100%, where W E : The mass of dried Swertia japonica extract, W X : The quality of the dried Swertia japonica medicinal material raw materials input and the experimental results are shown in Table 1.

[0075] Table 1

[0076] Serial number Extraction rate (%) Example 1 8.4 Example 2 8.9 Example 3 4.9 Example 4 7.7 Example 5 9.2 Example 6 9.3 Example 7 9.1 Example 8 5.6 Example 9 6.1 Example 10 6.4 Example 11 8.8 Example 12 9.3 Example 13 8.5

[0077] From the experimental results in Table 1, it can be seen that the method of extracting Swertia japonica extract by ionic liquid and microwave synergistically in the present invention can efficiently extract Swertia japonica extract. However, when the amount of ionic liquid added is less than 20%, the extraction rate does not increase significantly, and when the amount of ionic liquid added is higher than 30%, the extraction rate growth stops. In addition, the experimental results show that the optimal temperature for the first ultrasonic extraction is 60-70°C, and too high a temperature will reduce the extraction rate.

[0078] 2. Extraction rate test

[0079] Test object: Swertia japonica extract prepared in Example 1-2.

[0080] Test item: Active substances in Swertia japonica extract.

[0081] The test methods are as follows: Swertiamarin and gentiopicroside were tested using the HPLC method specified in the Chinese Pharmacopoeia; total flavonoids were determined using the aluminum nitrate-sodium nitrite colorimetric method specified in the Chinese Pharmacopoeia. Total triterpenes were determined using the vanillin-perchloric acid colorimetric method. Total phenolic acids were determined using the folin-ciocalteu colorimetric method (with gallic acid as the reference).

[0082] Yield (%) = [(C 提取物 ×W 提取物 ) / (C 药材 ×W 药材 )]×100%.

[0083] Where: C 提取物 : target component content in dry extract;

[0084] W 提取物 : total mass of dry extract;

[0085] C 药材 : The content of the target component in the dry extract used;

[0086] W 药材 : The total mass of the medicinal materials to be extracted.

[0087] The test results are detailed in Table 2.

[0088] Table 2

[0089]

[0090] It can be seen from the experimental results in Table 2 that the method for extracting Swertia japonica extract by ionic liquid and microwave synergism provided by the present invention can also efficiently extract swertiamarin, gentiopicroside, total flavonoids, total triterpenes and total phenolic acids with high extraction efficiency.

Claims

1. A method for extracting Swertia japonica extract by ionic liquid and microwave synergistic extraction, characterized in that: include: S1. Drying the Swertia japonica, then crushing and sieving the Swertia japonica to obtain Swertia japonica powder; S2, mixing the Swertia japonica powder and a solvent, then adding an ionic liquid, extracting under ultrasonic conditions for 20-30 minutes, and collecting a first filtrate and a first filter residue; S3, mixing the first filter residue and the solvent, adding a cell wall disruptor, performing a second ultrasonic extraction, and collecting a second filtrate and a second filter residue; S4. Combining the first filtrate and the second filtrate, then centrifuging, collecting the supernatant, and concentrating to obtain the Swertia japonica extract.

2. The method for extracting Swertia japonica extract by ionic liquid and microwave synergistic extraction according to claim 1, characterized in that: The drying process includes oven drying or natural sun drying.

3. The method for extracting Swertia japonica extract by ionic liquid and microwave synergistic extraction according to claim 2, characterized in that: The drying temperature is 50-60°C.

4. The method for extracting Swertia japonica extract by ionic liquid and microwave synergistic extraction according to claim 1, characterized in that: The mesh number of the crushing and screening is 20-100 meshes.

5. The method for extracting Swertia japonica extract by ionic liquid and microwave synergistic extraction according to claim 1, characterized in that: The solvent includes water.

6. The method for extracting Swertia japonica extract by ionic liquid and microwave synergistic extraction according to claim 1, characterized in that: The mass ratio of the Swertia japonica powder to the solvent is 1:(10-20).

7. The method for extracting Swertia japonica extract using ionic liquid and microwave synergistic extraction according to any one of claims 1 to 6, characterized in that: The ionic liquid includes 1-butyl-3-methylimidazolium bromide.

8. The method for extracting Swertia japonica extract by ionic liquid and microwave synergistic extraction according to claim 1, characterized in that: The power of ultrasonic extraction in step S1 is 280-350W.

9. The method for extracting Swertia japonica extract by ionic liquid and microwave synergistic extraction according to claim 8, characterized in that: The temperature of ultrasonic extraction in step S1 is 60-70°C.

10. The method for extracting Swertia japonica extract by ionic liquid and microwave synergistic extraction according to claim 1, characterized in that: The cell wall disrupting agent includes calcium carbonate or silicon dioxide.

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