A method for extracting artemisinin

Abstract

A method for extracting artemisinin, relating to the field of artemisinin extraction technology, includes the steps of extraction, enhanced extraction, separation, concentration, and purification. The purification employs an innovative column chromatography method, specifically a column height-to-diameter ratio of 1.2:1; adding hexane and diethyl ether eluent at a volume ratio of 8:2, with the added packing material height being 1.20-1.25 times the column diameter; and obtaining artemisinin after column chromatography. Alternatively, the innovative recrystallization method involves dissolving a paste in a crystallization vessel containing 50°C hot methanol, then lowering the temperature to 9-11°C, while locally heating and maintaining the temperature at the bottom of the crystallization vessel during cooling. Solid crystallization occurs under a uniform temperature distribution within the vessel, followed by filtration. This process is repeated twice to obtain artemisinin. The beneficial effects include an increased theoretical plate number of the chromatography column, significantly improved separation efficiency, and a significantly higher purity of artemisinin; the uniform temperature distribution within the crystallization vessel effectively improves the purity of the crystals.

Description

Technical Field

[0001] This invention relates to the field of artemisinin extraction technology, and specifically to a method for extracting artemisinin. Background Technology

[0002] Artemisia annua is the main source of artemisinin, a key precursor to the drug used to treat Plasmodium falciparum malaria. It is widely distributed in Chongqing, Anhui, Hubei, Shandong, and other regions of my country. As a traditional Chinese medicine, Artemisia annua is primarily used to treat fever and colds, and is recorded in classic texts such as the *Shennong Bencao Jing*, *Zhouhou Beiji Fang*, and *Compendium of Materia Medica*. In the 1970s, based on classical remedies and folk experience, Chinese scientists isolated and identified a novel sesquiterpene lactone containing peroxide bonds from Artemisia annua, naming it "artemisinin." Today, artemisinin has become a mainstream drug for treating falciparum malaria and intracerebral malaria, and is recognized by the World Health Organization as "the only effective treatment for malaria in the world."

[0003] Artemisinin is mainly extracted from plants. The effective components of traditional Chinese medicine can be extracted based on the differences in solubility of various components in different solvents. How to extract artemisinin more efficiently and ensure the purity of the product is a technical problem that needs to be solved in this field. An existing artemisinin extraction process includes (1) drying of the raw materials;

[0004] (2) Preliminary preparation of artemisinin: The treated raw material is extracted with petroleum ether and separated. The supernatant is eluted through a silica gel column. The resulting eluent is concentrated until crystals precipitate. It is then crystallized in a crystallizer for 15-20 hours. After crystallization, it is filtered to obtain crude artemisinin crystals. (3) Purification of artemisinin: The crude artemisinin crystals obtained in step (2) are dissolved and allowed to stand in an alcohol precipitation tank. The supernatant is coarsely filtered, the filtrate is concentrated, and after crystallization for 15-20 hours, the mother liquor is removed to obtain refined artemisinin. Although this method saves energy and reduces consumption, delays or abnormal reactions often occur during artemisinin synthesis. The reaction is not completed within the specified time, resulting in an additional increase in the consumption of important excipients such as sodium borohydride, which prolongs the process time and increases material costs. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for improving the purity of artemisinin by changing the height-to-diameter ratio of the chromatography column or the bottom insulation of the crystallizer, and to add a controlled extraction process to ensure the purity of artemisinin and avoid delays in artemisinin synthesis.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is a method for extracting artemisinin, including...

[0007] The following steps are required:

[0008] S1: Extraction: Add 1 part of Artemisia annua leaves to 2-40 parts of propylene glycol methyl ether solvent according to the solid-liquid ratio, and extract at 20-60℃ for 5 min to 3 h.

[0009] S2: Enhanced extraction: Adding mass transfer enhancement auxiliary means, wherein the mass transfer enhancement auxiliary means is one or more of heating and stirring, ultrasound or microwave.

[0010] S3: Separation: Liquid-solid separation is carried out by filtration or centrifugation to obtain an extract containing artemisinin.

[0011] S4: Concentration: The extract containing artemisinin is concentrated into a paste by vacuum evaporation.

[0012] S5: Purification: Artemisinin is obtained by column chromatography or recrystallization.

[0013] The column chromatography method is as follows: the paste is dissolved in methanol or ethanol solvent; silica gel is pretreated by drying and then dry-packed into a chromatography column and compacted; the height-to-diameter ratio of the chromatography column is 1.2:1; hexane and diethyl ether eluent are added in a volume ratio of 8:2; the height of the added packing material is 1.20-1.25 times the diameter of the chromatography column; artemisinin is obtained after column chromatography.

[0014] The key to this method lies in increasing the height-to-diameter ratio of the chromatography column. In existing elution methods, the height-to-diameter ratio of the chromatography column is 1:1. When the diameter of the chromatography column is 1300 mm, the packing height is 1300 mm. After changing the height-to-diameter ratio to 1.2:1, the packing height can be increased to 1600 mm, the theoretical plate number of the chromatography column is increased, the separation effect is significantly improved, and the purity of artemisinin is significantly improved.

[0015] The recrystallization method is as follows: the paste is dissolved in a crystallization tank containing 50°C hot methanol, and then the temperature is lowered to 9-11°C. During the cooling process, the bottom of the crystallization tank is locally heated and kept warm. In an environment with a uniform temperature distribution within the crystallization tank, solid crystals are precipitated, filtered, and the process is repeated twice to obtain artemisinin. The key to this method is to locally heat and keep warm the bottom of the crystallization tank during the cooling process. After the paste is dissolved in the crystallization tank, it will gradually crystallize during the cooling process. The crystallized crystals will sink to the bottom. The low temperature of the lower surface is difficult to conduct to the artemisinin solution in the upper part after direct contact with the crystals, resulting in uneven temperature distribution within the tank. A large number of impurities will adhere to the low-temperature crystals at the bottom. After locally heating and keeping warm the bottom area of ​​the crystallization tank, the temperature distribution within the crystallization tank is uniform, which can reduce the adhesion of impurities to the crystals and effectively improve the purity of the crystals.

[0016] S6: Control and detection: Take artemisinin and put it into anhydrous methanol, cool it down, then add sodium borohydride. After the reaction, take the reaction solution for spotting, and then judge whether further purification is needed based on the color development.

[0017] S7: Further purification: Repeat step 5, and further purify by column chromatography or recrystallization to obtain artemisinin.

[0018] The control and inspection method specifically includes the following steps:

[0019] S⑴ Artemisinin is added to anhydrous methanol at a solid-liquid ratio of 1:10, and the amount of artemisinin added is 5-20g. Then the temperature is lowered to 0-10℃.

[0020] Add 1-4g of sodium borohydride to S⑵ and react for 10-60min.

[0021] S⑶ Take 1 mL of the reaction solution, place it in a 5 mL centrifuge tube, add 1 mL of ethyl acetate, and shake well.

[0022] S⑷ Spotting: 2ul glass spotting capillary tube.

[0023] S⑸ Color development: 1% anisaldehyde sulfuric acid ethanol solution, heated at 105℃ until the spots are clear.

[0024] S⑹ Judgment: If the artemisinin spots disappear in the reaction solution, the artemisinin is qualified; if the artemisinin spots are obvious, the artemisinin is unqualified and needs to be further refined.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The height-to-diameter ratio of the chromatography column was changed to 1.2:1, and the height of the added packing material was 1.20-1.25 times the diameter of the chromatography column. The packing material height in a chromatography column with a diameter of 1300 mm could be increased to 1600 mm. The theoretical plate number of the chromatography column was increased, the separation effect was significantly improved, and the purity of artemisinin was significantly improved.

[0027] (2) During recrystallization cooling, the bottom of the crystallization tank is locally heated and kept warm to ensure uniform temperature distribution within the crystallization tank, which effectively improves the purity of the crystals.

[0028] (3) A control process was added to the extraction method, which can control the product quality during the extraction process and effectively improve the quality of artemisinin products. Attached Figure Description

[0029] Figure 1 This is a graph of anhydrous methanol reacting completely after 30 minutes on a silica gel G plate.

[0030] Figure 2 This is an abnormal reaction diagram of anhydrous methanol after 30 minutes on a silica gel G plate.

[0031] Figure 3 This is a graph of unreacted artemisinin in anhydrous methanol on a silica gel G plate. Detailed Implementation

[0032] The present invention will be further described below with reference to the embodiments. The following embodiments are intended to illustrate the present invention and not to further limit the present invention, and should not be used to limit the scope of protection of the present invention.

[0033] Example 1

[0034] S1: Extraction: Take 1 kg of dried, pulverized Artemisia annua leaf powder that has passed through a 40-mesh sieve, add 10 L of propylene glycol methyl ether, and extract at 20°C for 180 min.

[0035] S2: Enhanced extraction: Ultrasonic extraction with a power of 180W and a frequency of 20kHz is used in the S1 process.

[0036] S3: Separation: Filtration yields artemisinin extract.

[0037] S4: Concentration: The extract containing artemisinin is vacuum-evaporated at 55°C to obtain a paste containing artemisinin.

[0038] S5: Purification: Dissolve the paste in methanol, dry-pretreat the silica gel, and then dry-pack it into the chromatography column and press it tightly.

[0039] The height-to-diameter ratio of the chromatography column was 1.2:1; hexane and diethyl ether were added as eluent in a volume ratio of 8:2. The diameter of the chromatography column was 1300 mm and the packing height was 1560 mm. Artemisinin was obtained after silica gel column chromatography, and the purity of artemisinin was tested to be 97.5%.

[0040] S6: Inspection and Control

[0041] S⑴ Take 5g of artemisinin and add it to 50ml of anhydrous methanol. Stir and then cool to 1℃.

[0042] Add 1g of sodium borohydride to S⑵ and react for 10min.

[0043] S⑶ Take 1 mL of the reaction solution, place it in a 5 mL centrifuge tube, add 1 mL of ethyl acetate, and shake well.

[0044] S⑷ Spotting: 2ul glass spotting capillary tube.

[0045] S⑸ Color development: 1% anisaldehyde sulfuric acid ethanol solution, heated at 105℃ until the spots are clear.

[0046] S⑹ Judgment: If the artemisinin spots in the reaction solution disappear, the artemisinin is qualified.

[0047] Example 2

[0048] S1: Extraction: Take 1 kg of dried, pulverized Artemisia annua leaf powder that has passed through a 40-mesh sieve, add 15 L of propylene glycol methyl ether, and extract at 30℃ for 150 min.

[0049] S2: Enhanced extraction: Ultrasonic extraction with a power of 140W and a frequency of 20kHz is used in the S1 process.

[0050] S3: Separation: Filtration yields artemisinin extract.

[0051] S4: Concentration: The extract containing artemisinin is vacuum-evaporated at 55°C to obtain a paste containing artemisinin.

[0052] S5: Refining: Dissolve the paste in a crystallization tank containing 50°C hot methanol, then lower the temperature to 9°C.

[0053] During cooling, the bottom of the crystallization tank is locally heated and kept warm. In the environment of uniform temperature distribution in the crystallization tank, solid crystallizes out and then filters. Artemisinin is obtained by repeating this crystallization method twice. The purity of artemisinin is tested to be 93.5%.

[0054] S6: Inspection and Control

[0055] (1) Add 10g of artemisinin to 100ml of anhydrous methanol, stir and then cool to 3℃.

[0056] (2) Add 2g of sodium borohydride and react for 20min.

[0057] (3) Take 1 mL of the reaction solution, place it in a 5 mL centrifuge tube, add 1 mL of ethyl acetate, and shake well.

[0058] (4) Spotting: 2ul glass spotting capillary tube.

[0059] (5) Color development: 1% anisaldehyde sulfuric acid ethanol solution, heated at 105℃ until the spots are clear.

[0060] (6) Judgment: If the reaction solution shows obvious artemisinin spots, the artemisinin is unqualified.

[0061] S7: Further refining: Artemisinin is dissolved in a crystallization tank containing 50°C hot methanol, and then the temperature is lowered to 9°C. During the cooling process, the bottom of the crystallization tank is locally heated and kept warm. The solid crystallizes out under a uniform temperature distribution in the crystallization tank, and then filtered to obtain artemisinin. The purity of artemisinin is tested to be 95.5%.

[0062] S8: Inspection and Control

[0063] (1) Add 10g of artemisinin to 100ml of anhydrous methanol, stir and then cool to 3℃.

[0064] (2) Add 2g of sodium borohydride and react for 20min.

[0065] (3) Take 1 mL of the reaction solution, place it in a 5 mL centrifuge tube, add 1 mL of ethyl acetate, and shake well.

[0066] (4) Spotting: 2ul glass spotting capillary tube.

[0067] (5) Color development: 1% anisaldehyde sulfuric acid ethanol solution, heated at 105℃ until the spots are clear.

[0068] (6) Judgment: If the artemisinin spots in the reaction solution disappear, the artemisinin is qualified.

[0069] Example 3

[0070] S1: Extraction: Take 1 kg of dried, pulverized Artemisia annua leaf powder that has passed through a 40-mesh sieve, add 20 L of propylene glycol methyl ether, and extract at 35℃ for 90 min.

[0071] S2: Enhanced extraction: Ultrasonic extraction with a power of 200W and a frequency of 20kHz is used in the S1 process.

[0072] S3: Separation: Filtration yields artemisinin extract.

[0073] S4: Concentration: The extract containing artemisinin is vacuum-evaporated at 55°C to obtain a paste containing artemisinin.

[0074] S5: Purification: Dissolve the paste in methanol, dry-pretreat the silica gel, and then dry-pack it into the chromatography column and press it tightly.

[0075] The height-to-diameter ratio of the chromatography column was 1.2:1; hexane and diethyl ether were added as eluent in a volume ratio of 8:2. The diameter of the chromatography column was 1300 mm and the packing height was 1580 mm. Artemisinin was obtained after silica gel column chromatography, and the purity of artemisinin was tested to be 98.5%.

[0076] S6: Inspection and Control

[0077] S⑴ Take 10g of artemisinin and add it to 100ml of anhydrous methanol. Stir and then cool to 5℃.

[0078] Add 2g of sodium borohydride to S⑵ and react for 30min.

[0079] S⑶ Take 1 mL of the reaction solution, place it in a 5 mL centrifuge tube, add 1 mL of ethyl acetate, and shake well.

[0080] S⑷ Spotting: 2ul glass spotting capillary tube.

[0081] S⑸ Color development: 1% anisaldehyde sulfuric acid ethanol solution, heated at 105℃ until the spots are clear.

[0082] S⑹ Judgment: If the artemisinin spots in the reaction solution disappear, the artemisinin is qualified.

[0083] Example 4

[0084] S1: Extraction: Take 1 kg of dried, pulverized Artemisia annua leaf powder that has passed through a 40-mesh sieve, add 25 L of propylene glycol methyl ether, and extract at 40℃ for 90 min.

[0085] S2: Enhanced extraction: Ultrasonic extraction with a power of 180W and a frequency of 20kHz is used in the S1 process.

[0086] S3: Separation: Filtration yields artemisinin extract.

[0087] S4: Concentration: The extract containing artemisinin is vacuum-evaporated at 55°C to obtain a paste containing artemisinin.

[0088] S5: Refining: Dissolve the paste in a crystallization tank containing 50°C hot methanol, then lower the temperature to 10°C.

[0089] During cooling, the bottom of the crystallization tank is locally heated and kept warm. In the environment of uniform temperature distribution in the crystallization tank, solid crystallizes out and then filters. Artemisinin is obtained by repeating this crystallization method twice. The purity of artemisinin is tested to be 96.5%.

[0090] S6: Inspection and Control

[0091] (1) Add 15g of artemisinin to 150ml of anhydrous methanol, stir, and then cool to 5℃.

[0092] (2) Add 3g of sodium borohydride and react for 40min.

[0093] (3) Take 1 mL of the reaction solution, place it in a 5 mL centrifuge tube, add 1 mL of ethyl acetate, and shake well.

[0094] (4) Spotting: 2ul glass spotting capillary tube.

[0095] (5) Color development: 1% anisaldehyde sulfuric acid ethanol solution, heated at 105℃ until the spots are clear.

[0096] (6) Judgment: If the artemisinin spots in the reaction solution disappear, the artemisinin is qualified.

[0097] Example 5

[0098] S1: Extraction: Take 1 kg of dried, pulverized Artemisia annua leaf powder that has passed through a 40-mesh sieve, add 30 L of propylene glycol methyl ether, and extract at 50℃ for 60 min.

[0099] S2: Enhanced extraction: Ultrasonic extraction with a power of 200W and a frequency of 20kHz is used in the S1 process.

[0100] S3: Separation: Filtration yields artemisinin extract.

[0101] S4: Concentration: The extract containing artemisinin is vacuum-evaporated at 55°C to obtain a paste containing artemisinin.

[0102] S5: Purification: Dissolve the paste in methanol, dry-pretreat the silica gel, and then dry-pack it into the chromatography column and press it tightly.

[0103] The height-to-diameter ratio of the chromatography column was 1.2:1; hexane and diethyl ether were added as eluent in a volume ratio of 8:2. The diameter of the chromatography column was 1300 mm and the height of the packing material was 1600 mm. Artemisinin was obtained after silica gel column chromatography, and the purity of artemisinin was tested to be 98%.

[0104] S6: Inspection and Control

[0105] S⑴ Take 20g of artemisinin and add it to 200ml of anhydrous methanol. Stir and then cool to 7℃.

[0106] Add 4g of sodium borohydride to S⑵ and react for 50min.

[0107] S⑶ Take 1 mL of the reaction solution, place it in a 5 mL centrifuge tube, add 1 mL of ethyl acetate, and shake well.

[0108] S⑷ Spotting: 2ul glass spotting capillary tube.

[0109] S⑸ Color development: 1% anisaldehyde sulfuric acid ethanol solution, heated at 105℃ until the spots are clear.

[0110] S⑹ Judgment: If the artemisinin spots in the reaction solution disappear, the artemisinin is qualified.

[0111] Example 6

[0112] S1: Extraction: Take 1 kg of dried, pulverized Artemisia annua leaf powder that has passed through a 40-mesh sieve, add 40 L of propylene glycol methyl ether, and extract at 60℃ for 45 min.

[0113] S2: Enhanced extraction: Ultrasonic extraction with a power of 180W and a frequency of 20kHz is used in the S1 process.

[0114] S3: Separation: Filtration yields artemisinin extract.

[0115] S4: Concentration: The extract containing artemisinin is vacuum-evaporated at 55°C to obtain a paste containing artemisinin.

[0116] S5: Refining: Dissolve the paste in a crystallization tank containing 50°C hot methanol, then lower the temperature to 11°C.

[0117] During cooling, the bottom of the crystallization tank is locally heated and kept warm. In the environment of uniform temperature distribution in the crystallization tank, solid crystallizes out and then filters. After repeating this crystallization method twice, artemisinin is obtained. The purity of artemisinin is tested to be 95%.

[0118] S6: Inspection and Control

[0119] (1) Take 20g of artemisinin and put it into 200ml of anhydrous methanol. Stir and then cool it down to 10℃.

[0120] (2) Add 4g of sodium borohydride and react for 60min.

[0121] (3) Take 1 mL of the reaction solution, place it in a 5 mL centrifuge tube, add 1 mL of ethyl acetate, and shake well.

[0122] (4) Spotting: 2ul glass spotting capillary tube.

[0123] (5) Color development: 1% anisaldehyde sulfuric acid ethanol solution, heated at 105℃ until the spots are clear.

[0124] (6) Judgment: If the reaction solution shows obvious artemisinin spots, the artemisinin is unqualified.

[0125] S7: Further refining: Artemisinin is dissolved in a crystallization tank containing 50°C hot methanol, and then the temperature is lowered to 11°C. During the cooling process, the bottom of the crystallization tank is locally heated and kept warm. The solid crystallizes out under a uniform temperature distribution in the crystallization tank, and then is filtered to obtain artemisinin. The purity of artemisinin is tested to be 96.5%.

[0126] S8: Inspection and Control

[0127] (1) Take 20g of artemisinin and put it into 200ml of anhydrous methanol. Stir and then cool it down to 10℃.

[0128] (2) Add 4g of sodium borohydride and react for 60min.

[0129] (3) Take 1 mL of the reaction solution, place it in a 5 mL centrifuge tube, add 1 mL of ethyl acetate, and shake well.

[0130] (4) Spotting: 2ul glass spotting capillary tube.

[0131] (5) Color development: 1% anisaldehyde sulfuric acid ethanol solution, heated at 105℃ until the spots are clear.

[0132] (6) Judgment: If the artemisinin spots in the reaction solution disappear, the artemisinin is qualified.

[0133] Comparative Example 1 (using a chromatography column with a height-to-diameter ratio of 1:1)

[0134] S1: Extraction: Take 1 kg of dried, pulverized Artemisia annua leaf powder that has passed through a 40-mesh sieve, add 20 L of propylene glycol methyl ether, and extract at 35℃ for 90 min.

[0135] S2: Enhanced extraction: Ultrasonic extraction with a power of 200W and a frequency of 20kHz is used in the S1 process.

[0136] S3: Separation: Filtration yields artemisinin extract.

[0137] S4: Concentration: The extract containing artemisinin is vacuum-evaporated at 55°C to obtain a paste containing artemisinin.

[0138] S5: Purification: Dissolve the paste in methanol, dry-pretreat the silica gel, and then dry-pack it into the chromatography column and press it tightly.

[0139] The height-to-diameter ratio of the chromatography column was 1:1; hexane and diethyl ether were added as eluent in a volume ratio of 8:2. The diameter of the chromatography column was 1300 mm and the packing height was 1620 mm. Artemisinin was obtained after silica gel column chromatography, and the purity of artemisinin was tested to be 93.5%.

[0140] S6: Inspection and Control

[0141] S⑴ Take 10g of artemisinin and add it to 100ml of anhydrous methanol. Stir and then cool to 5℃.

[0142] Add 2g of sodium borohydride to S⑵ and react for 30min.

[0143] S⑶ Take 1 mL of the reaction solution, place it in a 5 mL centrifuge tube, add 1 mL of ethyl acetate, and shake well.

[0144] S⑷ Spotting: 2ul glass spotting capillary tube.

[0145] S⑸ Color development: 1% anisaldehyde sulfuric acid ethanol solution, heated at 105℃ until the spots are clear.

[0146] S⑹ Judgment: If the reaction solution shows obvious artemisinin spots, the artemisinin is unqualified.

[0147] Comparative Example 2 (Crystallization tank without heating and insulation)

[0148] S1: Extraction: Take 1 kg of dried, pulverized Artemisia annua leaf powder that has passed through a 40-mesh sieve, add 25 L of propylene glycol methyl ether, and extract at 40℃ for 90 min.

[0149] S2: Enhanced extraction: Ultrasonic extraction with a power of 180W and a frequency of 20kHz is used in the S1 process.

[0150] S3: Separation: Filtration yields artemisinin extract.

[0151] S4: Concentration: The extract containing artemisinin is vacuum-evaporated at 55°C to obtain a paste containing artemisinin.

[0152] S5: Refining: Dissolve the paste in a crystallization tank containing 50°C hot methanol, then lower the temperature to 10°C.

[0153] The solid was crystallized out and then filtered. This process was repeated twice to obtain artemisinin, which was found to have a purity of 90.5%.

[0154] S6: Inspection and Control

[0155] (1) Add 15g of artemisinin to 150ml of anhydrous methanol, stir, and then cool to 5℃.

[0156] (2) Add 3g of sodium borohydride and react for 40min.

[0157] (3) Take 1 mL of the reaction solution, place it in a 5 mL centrifuge tube, add 1 mL of ethyl acetate, and shake well.

[0158] (4) Spotting: 2ul glass spotting capillary tube.

[0159] (5) Color development: 1% anisaldehyde sulfuric acid ethanol solution, heated at 105℃ until the spots are clear.

[0160] (6) Judgment: If the reaction solution shows obvious artemisinin spots, the artemisinin is unqualified.

[0161] Therefore, the purity of artemisinin obtained after chromatography using a column with a height-to-diameter ratio of 1.2:1 is as follows:

[0162] Experimental conditions and methods; practical difficulties overcome in the experiment.

[0163] Therefore, the artemisinin purities obtained by chromatography using a 1.2:1 aspect ratio column were 97.5%, 98.5%, and 98%, respectively, while the purity obtained by chromatography using a 1:1 aspect ratio column was only 93.5%. The artemisinin purities obtained by locally heating and maintaining the bottom of the crystallization tank during recrystallization cooling were 93.5%, 96.5%, and 95%, respectively, while the existing method, which did not heat and maintain the crystallization tank during recrystallization cooling, had a purity of only 90.5%. This demonstrates that the method of this invention effectively improves the purity of artemisinin. The adoption of a controlled inspection process during extraction allows for real-time monitoring of the artemisinin product quality, effectively preventing delayed reactions or abnormal reactions during the synthesis of downstream products.

Claims

1. A method for extracting artemisinin, characterized in that It comprises the following steps: S1: extraction: 1 part of Artemisia annua leaves is put into 2-40 parts of propylene glycol methyl ether solvent according to the solid-liquid ratio, and extraction is carried out at 20-60℃ for 5 min-3 h; S2: enhanced extraction: an enhanced mass transfer auxiliary means is added, which is one or several of heating stirring, ultrasonic or microwave; S3: separation: liquid-solid separation is carried out by filtration or centrifugation to obtain an extract containing artemisinin; S4: concentration: the extract containing artemisinin is concentrated into a paste by vacuum evaporation; S5: refining: column chromatography or recrystallization method is used for refining; When column chromatography method is used, the paste is dissolved with methanol or ethanol solvent, silica gel is pretreated by drying and then dry-packed into a chromatography column and compressed, the height-diameter ratio of the chromatography column is 1.2:1, the eluent is n-hexane and diethyl ether with a volume ratio of 8:2, the height of the added filler is 1.20-1.25 times the diameter of the chromatography column, and artemisinin is obtained after column chromatography; When recrystallization method is used, the paste is put into a crystallization tank containing hot methanol at 50℃ for dissolution, then the temperature is reduced to 9-11℃, local heating is carried out on the bottom of the crystallization tank during temperature reduction, solid is crystallized and separated out under the condition of uniform temperature distribution in the crystallization tank, then filtration is carried out, and artemisinin is obtained after repeating twice; S6: control and inspection: artemisinin obtained after refining is put into anhydrous methanol, the solid-liquid ratio of artemisinin to anhydrous methanol is 1:10, the amount of the material is 5-20 g, then the temperature is reduced to 0-10℃, 1-4 g of sodium borohydride is added, and the reaction is carried out for 10-60 min, 1 mL of the reaction solution is taken, 1 mL of ethyl acetate is added, shaken well, 2 μl of the sample is spotted on a silica gel plate with a glass spotting capillary, colored with 1% anisaldehyde sulfuric acid ethanol solution, heated at 105℃ until the spots are clear, if the artemisinin spot of the reaction solution disappears, the artemisinin is qualified, if the artemisinin spot is obvious, the artemisinin is unqualified; S7: re-refining: if the artemisinin is unqualified in step S6, the artemisinin is re-refined by repeating step S5 until the control and inspection are qualified.

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