阅读说明：本技术 从***中提取***二酚的方法 (Method for extracting cannabidiol from cannabis sativa ) 是由 于朝晖 常坦然 高伟博 柳旭 于 2019-04-30 设计创作，主要内容包括：本发明涉及医药技术领域,特别涉及大麻二酚(CBD)的制备方法,本发明制备方法包括提取、脱羧、酸水沉降、纯化、结晶等步骤,本发明中采用提取后转化脱羧可以使脱羧更完全；酸水沉极大提升大麻二酚(CBD)的得率；用大孔型离子交换树脂柱层析纯化,除杂效果更好；刮板式桨叶与特定溶媒组合的动态结晶工艺结晶效率更高,更适合大规模的生产,且所得晶体的物理性征相对更佳,利于后续制剂开发；通过本发明方法制备所得的CBD原料能够达到注射级别的要求,延伸了其现代化应用的范畴。(The invention relates to the technical field of medicines, in particular to a preparation method of Cannabidiol (CBD), which comprises the steps of extraction, decarboxylation, acid water sedimentation, purification, crystallization and the like, wherein the decarboxylation can be more complete by adopting conversion decarboxylation after extraction; the acid water precipitation greatly improves the yield of Cannabidiol (CBD); the macroporous ion exchange resin column chromatography is used for purification, so that the impurity removal effect is better; the dynamic crystallization process combining the scraper blade and the specific solvent has higher crystallization efficiency, is more suitable for large-scale production, and the obtained crystal has relatively better physical characteristics, thereby being beneficial to the development of subsequent preparations; the CBD raw material prepared by the method can meet the requirement of injection grade, and the scope of modern application of the CBD raw material is extended.)

1. The method for extracting cannabidiol from cannabis is characterized by comprising the following steps:

step 1: pulverizing and drying Cannabis sativa to obtain Cannabis sativa powder;

step 2: extracting hemp powder with alcohol, collecting extractive solution, concentrating, mixing with water, decarboxylating, and concentrating to obtain extract; the decarboxylation temperature is 60-130 ℃, and the time is 1-3 h;

and step 3: mixing the extract with water, adjusting the pH value to 3.5-6.5, precipitating with water, centrifuging, collecting precipitate, mixing with ethanol, purifying, and performing third concentration to obtain a concentrated solution; then decolorizing and desensitizing, filtering, and concentrating for the fourth time to obtain thick paste;

and 4, step 4: mixing the thick paste with a solvent at 10-80 ℃, continuously stirring for crystallization at-10-20 ℃ for 12-72 h, washing and drying.

2. The method of claim 1, wherein the cannabis is one or a combination of two or more of industrial cannabis, intermediate cannabis, or pharmaceutical cannabis;

the extraction part of the hemp is one or the combination of more than two of hemp flowers, hemp leaves, hemp roots, hemp stem cores or hemp seed meal.

3. The method of claim 1 or 2, wherein the pulverizing in step 1 is to 10 to 80 mesh.

4. The method according to any one of claims 1 to 3, wherein in the step 2, ethanol extraction is performed by using 30-100% (V/V) ethanol, and the extraction comprises reflux extraction, ultrasonic extraction and/or soaking extraction; the alcohol extraction frequency is 1-3;

the reflux extraction comprises the following steps: carrying out reflux extraction for 1-3 times by adopting 2-10 times of ethanol in the amount of the medicinal materials, wherein each time is 0.5-3 hours;

the ultrasonic extraction comprises the following steps: carrying out ultrasonic extraction for 1-3 times by adopting 2-10 times of ethanol in the amount of the medicinal materials, wherein each time is 0.1-1 h;

the soaking extraction comprises the following steps: soaking and extracting for 1-3 times by using 2-10 times of ethanol, and each time lasts for 0.5-5 hours.

5. The method according to any one of claims 1 to 4, wherein the first or second concentration in step 2 is carried out at 50-70 ℃ under reduced pressure to a relative density of 1.05-1.35 (measured at 50 ℃).

6. The method according to any one of claims 1 to 5, wherein the amount of water added in step 2 is 1/10-1/100 times (W/V) the amount of the medicinal material.

7. The method according to any one of claims 1 to 6, wherein the amount of the water used in the step 3 is 1-10 times of the amount of the medicinal material, the temperature of the water precipitation is 0-20 ℃, and the time of the water precipitation is 1-48 h;

The rotating speed of the centrifugation is 4000 rpm-10000 rpm, and the time of the centrifugation is 3 min-30 min.

8. The method of any one of claims 1 to 7, wherein the purification in step 3 is column chromatography loaded with a macroporous ion exchange resin, and the column chromatography is subjected to gradient elution with an elution solvent; the gradient elution is: removing impurities by using 0.05-2% (M/M) alkaline water, and eluting by using 60-80% (V/V) acidic ethanol with the pH of 2-5 to obtain an eluent; the third concentration is carried out at 50-70 ℃ under reduced pressure until the relative density is 1.05-1.25 (measured at 50 ℃), and the alcoholic strength is 40-70%.

9. The method according to any one of claims 1 to 8, wherein the discoloration desensitization in step 3 is carried out by using activated carbon in an amount of 0.2% to 0.5% (W/W) based on the mass of cannabidiol in the concentrate, the temperature of the discoloration desensitization is 45 ℃ to 75 ℃, and the time of the discoloration desensitization is 0.5h to 1 h; the filtration is filter pressing or suction filtration, and the aperture of the filter screen adopted by the filtration is not less than 400 meshes.

10. The method of any one of claims 1 to 9, wherein the solvent in step 4 is one or a combination of two of butane, pentane, hexane, heptane, ethyl acetate, acetone or ethanol; washing with water or 5-40% (V/V) ethanol at 0-24 deg.C; the drying comprises one or more of spray drying, vacuum drying, freeze drying, near infrared drying or microwave drying, and the drying temperature is 30-65 ℃.

Technical Field

The invention relates to the technical field of medicines, in particular to a method for extracting cannabidiol from cannabis sativa.

Background

Industrial hemp (Cannabis sativa L.) is a plant of Cannabis of Moraceae, has Tetrahydrocannabinol (THC) content of less than three thousandths in the flower and leaf in the growth period, has no value of extracting tetrahydrocannabinol or can be directly sucked as drug, can be legally planted in large scale and industrially exploited, and has extremely high economic and medicinal values.

The cannabinol compounds are active substances contained in cannabis plants, and mainly comprise Tetrahydrocannabinol (THC), Tetrahydrocannabinoid (THCV), Cannabidiol (CBD), Cannabigerol (CBG), and Cannabidivarin (CBDV), and the five of the above substances account for more than 90% of cannabinol compounds. Cannabidiol (CBD), one of the most important non-addictive components in plants, has pharmacological activities such as anti-spasmodic, anti-rheumatic arthritis, and anti-anxiety, and can hinder the adverse effects of Tetrahydrocannabinol (THC) on the human nervous system, and has become a hot spot in drug development.

Patent PCT/CN2017/071993, mentions a process for extracting cannabidiol from cannabis: crushing the extraction part of cannabis sativa, drying, processing to obtain medicinal powder, extracting with 30-100% (V/V) ethanol to obtain an extract, concentrating under reduced pressure to obtain an extract, adding water while hot for water precipitation, removing water layer impurities, adding 10-100% (V/V) ethanol into the precipitate for dissolution, performing column chromatography to obtain a target product rich in CBD, crystallizing with organic solvents such as ethanol, washing the crystal, and drying to obtain the cannabidiol finished product with the purity of about 99%.

However, with the continuous scale-up of production and the increasing demand of the market for CBD quality, the process gradually presents the following problems:

1) The decarboxylation link for the processing of the hemp flowers and leaves has high requirements on production equipment after enlarged production due to the special fluffiness of the hemp flowers and leaves, is very easy to become a speed-limiting link, and due to the enlargement effect, the decarboxylation proportion is reduced in different degrees, so that the obvious batch-to-batch and batch-to-batch differences are caused;

2) because the quality of flowers and leaves is difficult to be uniform (such as old leaves, new leaves, different soil masses and the like), when electrolyte components (sources and compositions are not clear) in the water sedimentation liquid are more, the electrolyte components and cannabinoid components are easy to form small micelles which are dispersed in the water sedimentation liquid and are discharged along with waste water to cause the loss of a large amount of target products;

3) after flower and leaf extraction and purification, crystallization is carried out at low temperature or normal temperature and pressure, standing is carried out for 12-72h, due to amplification effect, the purity difference of different crystallization parts (such as crystal surface, tank body side wall and bottom) in single crystallization is large, and after mixing, the content is not more than 99%, and recrystallization is needed; in addition, the crystals so formed are typically large and very compact, difficult to harvest and pulverize, and are not yet suitable for scale-up production requirements.

4) Through the process, a finished product with high purity can be obtained, but the safety of the finished product as an injection-grade raw material cannot be guaranteed, and industrial application is influenced.

Therefore, there is a need to provide a method for preparing cannabidiol in a large-scale and industrial manner with high efficiency and safe quality, so as to promote the development of the cannabis industry with ever-increasing market demand.

Disclosure of Invention

In view of the above, the present invention provides a method for extracting cannabidiol from cannabis sativa. The invention provides a preparation method of an injection-grade cannabidiol raw material, which aims to solve the problems of high loss, low efficiency and the like of the prior art, fundamentally solve the problem of crystallization industrialization and simultaneously ensure that a CBD finished product can meet the requirements of the injection-grade raw material.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a method for extracting cannabidiol from cannabis sativa, which comprises the following steps:

step 1: pulverizing and drying hemp to obtain hemp powder;

step 2: extracting hemp powder with alcohol, collecting extractive solution, concentrating, mixing with water, decarboxylating, and concentrating to obtain extract; the decarboxylation temperature is 60-130 ℃, and the time is 1-3 h;

and step 3: mixing the extract with water, adjusting the pH value to 3.5-6.5, precipitating with water, centrifuging, collecting precipitate, mixing with ethanol, purifying, and performing third concentration to obtain a concentrated solution; then decolorizing and desensitizing, filtering, and concentrating for the fourth time to obtain thick paste;

And 4, step 4: mixing the thick paste with a solvent at 10-80 ℃, continuously stirring for crystallization at-10-20 ℃ for 12-72 h, washing and drying.

In some embodiments of the invention, the cannabis is one or a combination of two or more of industrial, intermediate, or pharmaceutical cannabis.

In some embodiments of the invention, the extraction site of cannabis is one or a combination of two or more of cannabis flowers, cannabis leaves, cannabis roots, cannabis stem cores, or cannabis seed meal.

In some embodiments of the present invention, the pulverization in step 1 is to 10 to 80 mesh.

In some specific embodiments of the invention, the alcohol extraction in step 2 is performed by 30-100% (V/V) ethanol extraction, and the extraction includes reflux extraction, ultrasonic extraction and/or immersion extraction; the alcohol extraction frequency is 1-3.

In some embodiments of the invention, the reflux extraction comprises: carrying out reflux extraction for 1-3 times by adopting 2-10 times of ethanol in the amount of the medicinal materials, wherein each time is 0.5-3 hours;

the ultrasonic extraction comprises the following steps: carrying out ultrasonic extraction for 1-3 times by adopting 2-10 times of ethanol in the amount of the medicinal materials, wherein each time is 0.1-1 h;

the soaking extraction comprises the following steps: soaking and extracting for 1-3 times by using 2-10 times of ethanol, and each time lasts for 0.5-5 hours.

In some embodiments of the invention, the first or second concentration in step 2 is from 50 to 70 ℃ and reduced pressure concentration to a relative density of 1.05 to 1.35 (measured at 50 ℃).

In some embodiments of the present invention, the amount of the water added in step 2 is 1/10-1/100 times (W/V) of the crude drug.

In some embodiments of the present invention, the pH adjustment is performed with an organic acid, an inorganic acid or a base, which may include one or more of formic acid, acetic acid, oxalic acid, hydrochloric acid, nitric acid, sulfuric acid, and the like. More preferred are formic acid, oxalic acid and hydrochloric acid. The alkali is sodium hydroxide, potassium hydroxide or ammonia water, and sodium hydroxide is more preferable.

In some specific embodiments of the invention, the amount of the water used in the step 3 is 1-10 times of the amount of the medicinal materials, the water precipitation temperature is 0-20 ℃, and the water precipitation time is 1-48 h.

In some embodiments of the invention, the rotation speed of the centrifugation is 4000rpm to 10000rpm, and the time of the centrifugation is 3min to 30 min.

In some embodiments of the invention, the mass-to-volume ratio of the precipitate to the ethanol in step 3 is 4 (1-4); the purification is column chromatography of macroporous ion exchange resin, and the column chromatography adopts an elution solvent for gradient elution; the gradient elution is: removing impurities by using 0.05-2% (M/M) alkaline water, and eluting by using 60-80% (V/V) acidic ethanol with the pH of 2-5 to obtain an eluent; the third concentration is carried out at 50-70 ℃ under reduced pressure until the relative density is 1.05-1.25 (measured at 50 ℃), and the alcoholic strength is 40-70%. The alkaline water for gradient elution is aqueous solution of sodium hydroxide, potassium hydroxide or ammonia water, more preferably aqueous solution of sodium hydroxide

In some embodiments of the invention, the packing of the chromatography column comprises strong base No. 4, strong base DKx4, shanghai 763^#、^#702 weak base resin, one or more of D301, D303, D380, D301K and macroporous weak base resin.

In some embodiments of the invention, the step of gradient elution comprises removing impurities with 0.05-2% (M/M) alkaline water, eluting with 60-80% (V/V) acidic ethanol with pH of 2-5 to obtain a target product fraction, and washing the column with 90-95% (V/V) acidic ethanol with pH of 2-5 to regenerate the chromatography column. The gradient elution step not only ensures that the target product has high partial purity and good color, but also ensures that the chromatographic column is continuously regenerated and can be recycled.

In some specific embodiments of the invention, the decolorization and desensitization in step 3 is performed by using activated carbon, the addition amount of the activated carbon is 0.2-0.5% (W/W) of the mass of cannabidiol in the concentrated solution, the temperature of the decolorization and desensitization is 45-75 ℃, and the time of the decolorization and desensitization is 0.5-1 h; the filtration is filter pressing or suction filtration, and the aperture of the filter screen adopted by the filtration is not less than 400 meshes.

In some embodiments of the invention, the activated carbon is in the form of a powder or granules of 0.05mm to 0.5 mm.

In some embodiments of the invention, the solvent in step 4 is one or a combination of two of butane, pentane, hexane, heptane, ethyl acetate, acetone or ethanol; washing with water or 5-40% (V/V) ethanol at 0-24 deg.C; the drying comprises one or more of spray drying, vacuum drying, freeze drying, near infrared drying or microwave drying, and the drying temperature is 30-65 ℃.

Preferably, the drying temperature is 40 ℃ to 55 ℃.

In some embodiments of the invention, the drying is followed by a comminution step, the comminution comprising steam milling and/or freeze milling, the comminution temperature being from 0 ℃ to 65 ℃.

In some embodiments of the invention, the vehicle is a combination of one or more of hexane, heptane, ethyl acetate, acetone, or ethanol. Here, ethanol (or acetone) refers to an ethanol-water (or acetone-water) system, and the crystal concentration is 5% to 65% (V/V), more preferably 10% to 25% (V/V).

The invention extracts Cannabidiol (CBD) from cannabis sativa, and comprehensively optimizes the process route in continuous amplification: 1) conversion decarboxylation after extraction can make decarboxylation more complete (see fig. 6); 2) the acid water precipitation greatly improves the yield of Cannabidiol (CBD); 3) macroporous ion exchange resin column chromatography is adopted, the impurity removal effect is better 4) the dynamic crystallization process of the combination of the scraper blade and the specific solvent has higher crystallization efficiency, is suitable for large-scale production (see figure 7), and the obtained crystal has relatively better physical characteristics, thus being beneficial to the development of subsequent preparations; 5) the CBD raw material prepared by the method can meet the requirement of injection grade, and the scope of modern application of the CBD raw material is extended.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.

FIG. 1 shows a chromatogram of a CBD standard (sigma);

FIG. 2 shows a chromatogram of CBD product 1;

FIG. 3 shows a chromatogram of CBD product 2;

FIG. 4 shows a chromatogram of CBD product 3;

FIG. 5 shows a chromatogram of CBD product 4;

FIG. 6 shows a chromatogram of a sample solution; wherein, FIG. 6(A) shows product 4 (decarboxylation followed by extraction) prepared in comparative example, and FIG. 6(B) shows product 1 (extraction followed by decarboxylation) prepared in example 1 of the present invention;

FIG. 7 shows a plot of a crystallized sample; wherein, FIGS. 7(A) to 7(B) show crystal samples of example 1 of the present invention; fig. 7(C) to 7(E) are crystal samples of comparative examples.

Detailed Description

The invention discloses a method for extracting cannabidiol from cannabis sativa, which can be realized by appropriately improving process parameters by referring to the content in the text. It is expressly intended that all such similar substitutes and modifications which would be obvious to one skilled in the art are deemed to be included in the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

The invention aims to provide a preparation method of an injection-grade cannabidiol raw material, which aims to solve the problems of high loss, low efficiency and the like of the prior art and push the quality of a CBD finished product to the height of an injection grade.

In order to achieve the above objects, the present invention provides a method for extracting cannabidiol from cannabis sativa, the method comprising the steps of:

1) pulverizing the extract of Cannabis sativa L to obtain medicinal powder;

2) extracting the medicinal material powder by using 30-100% (V/V) ethanol to obtain an extracting solution;

concentrating the extracting solution under reduced pressure until no alcohol exists, recovering ethanol, adding 1/10-1/100 times (W/V) of purified water of the medicinal material, decarboxylating, and continuing concentrating for 1-2 h under normal pressure to obtain an extract; the decarboxylation temperature is 60-130 ℃, and the time is 1-3 h;

3) dispersing the extract in purified water, adjusting the pH to 3.5-6.5 by using organic acid or inorganic acid, removing water-soluble impurities, and simultaneously settling CBD to the maximum extent to obtain a water settling solution;

centrifuging the water precipitation solution, and adding 10-100% (V/V) ethanol into the precipitate obtained by centrifuging to dissolve the precipitate to obtain an alcohol solution of the precipitate; carrying out column chromatography on the alcohol solution of the precipitate;

concentrating the target section eluent under reduced pressure until the density is 1.05-1.25 (the alcoholic strength is 40-70%), putting the eluent into a decoloring tank, adding active carbon according to 0.2-0.5% of the total content (W/W) of CBD, stirring for 0.5-1 h at 45-75 ℃, and filtering to obtain decoloring and desensitizing liquid for removing heat sources;

4) Concentrating the decolorized and desensitized solution obtained in the step 7) to an anhydrous thick paste, adding a specific solvent for supersaturation and dissolution, placing the supernatant in a crystallizing tank, cooling to normal temperature, continuously stirring and crystallizing for 12-72 hours, and finally obtaining crystals with uniform particle size;

adding purified water or ethanol into the crystal, and washing to obtain a primary product;

drying the obtained primary product by a proper drying method, and crushing to obtain the finished product of cannabidiol.

Preferably, the cannabis of the invention is selected from one or a combination of more than two of industrial cannabis, intermediate cannabis or medicinal cannabis.

Preferably, the extraction part in the step 1) is one or a combination of more than two of hemp flowers, hemp leaves, hemp roots, hemp stalk cores and hemp seed meal. Preferably, the extraction part in the step 1) is cannabis flos and cannabis leaves.

Preferably, the hemp extract part is pulverized to 10-80 meshes in step 1), for example, 10 meshes, 12 meshes, 14 meshes, 16 meshes, 18 meshes, 20 meshes, 25 meshes, 30 meshes, 35 meshes, 40 meshes, 45 meshes, 50 meshes, 60 meshes, 70 meshes, 80 meshes and the like; further preferably 20-60 meshes; more preferably 25-50 mesh; most preferably 40 mesh. In an exemplary embodiment of the present invention, the cannabis flowers and leaves are crushed in step 1) to the mesh size range, so that the cannabidiol can be fully extracted in the subsequent ethanol extraction step.

Preferably, the amount of the ethanol used in step 2) of the present invention is 4-10 times of the amount of the medicinal material, for example, 4 times, 4.5 times, 5 times, 6 times, 7 times, 8 times, 9 times, 10 times of the amount of the medicinal material; further preferably 4-8 times of the amount of the medicinal materials; more preferably 4-6 times of the amount of the medicinal materials.

Preferably, the number of times of ethanol extraction in the step 2) is 1-3.

Preferably, the ethanol extraction in step 2) of the present invention is performed by reflux extraction, ultrasonic extraction and/or immersion extraction.

Further preferably, the reflux extraction time is 0.5-3 h for each extraction; the ultrasonic extraction time is 0.1-lh per time; the soaking extraction time is 0.5-5 h per time.

In an exemplary embodiment of the present invention, the step 2) is: extracting the medicinal material powder for 1-3 times by adopting 30-100% (V/V) ethanol 4-8 times of the medicinal material amount to obtain an extracting solution.

Preferably, in the step 2), the relative density of the concentrated extract measured at 50 ℃ is 1.05-1.35.

Preferably, the water consumption of the water precipitation in the step 3) of the present invention is 1 to 10 times of the amount of the medicinal material, for example, 1 time, 1.1 time, 1.2 times, 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2 times, 2.25 times, 2.5 times, 3 times, 3.5 times, 4 times, 4.5 times, 5 times, 5.5 times, 6 times, 6.5 times, 7 times, 7.5 times, 8 times, 8.5 times, 9 times, 9.5 times, 10 times of the amount of the medicinal material; further preferably 2-8 times of the amount of the medicinal materials; more preferably 3-6 times of the amount of the medicinal materials.

Preferably, the acid for adjusting pH by water precipitation in step 3) of the present invention is one or more of formic acid, acetic acid, oxalic acid, hydrochloric acid, nitric acid, sulfuric acid, and the like. More preferred are formic acid, oxalic acid and hydrochloric acid. The alkali is sodium hydroxide, potassium hydroxide or ammonia water, and sodium hydroxide is more preferable. Preferably, the water-precipitation pH in step 3) of the present invention is adjusted to 2.5 to 6.5, and may be, for example, 2.5, 2.7, 2.9, 3.0, 3.3, 3.5, 3.7, 3.9, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, and the like, and more preferably 3.5 to 5.5.

Preferably, the water precipitation temperature in step 3) of the present invention is 0 to 20 ℃, for example, 0 ℃, 0.1 ℃, 0.5 ℃, 0.8 ℃, 1.0 ℃, 1.5 ℃, 1.75 ℃, 2 ℃, 3 ℃, 4 ℃, 5 ℃, 6 ℃, 7 ℃, 8 ℃, 9 ℃, 10 ℃, 11 ℃, 13 ℃, 15 ℃, 17 ℃, 18 ℃, 19 ℃, 20 ℃ and the like; further preferably 2-18 ℃; more preferably 5 to 15 ℃.

Preferably, the water settling time in step 3) of the present invention is l-48h, and may be, for example, lh, l.lh, 1.3h, 1.5h, 1.9h, 2h, 2.5h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 15h, 20h, 30h, 40h, 48h, etc.; further preferably 2-36 h; more preferably 5-30 h.

In an exemplary embodiment of the present invention, the step 3) is: and (3) carrying out water precipitation on the extract for l-48 h at the temperature of 0-20 ℃ by using purified water with the amount of 1-10 times that of the medicinal materials, and removing impurities to obtain a water precipitation solution.

Preferably, the packing of the column used in the column chromatography of step 3) of the present invention includes, but is not limited to, strong base No. 4, strong base DKx4, shanghai 763^#、^#702 weak base resin, one or more of D301, D303, D380, D301K macroporous weak base resin and ODS filler (namely octadecyl bonded silica gel); further preferably, the macroporous strongly basic anion exchange resin DKx4 and/or the macroporous weakly basic anion exchange resins D303 and D301K; more preferably DKx4 resin. .

Preferably, in the step 3), the column chromatography is performed by gradient elution of a chromatography column by using an elution solvent; the elution solvent is preferably an acidic organic solvent and/or acid or alkaline water; further preferably, the step of gradient elution comprises: removing impurities by 0.05-2% (M/M) alkaline water, and eluting by 60-80% (V/V) acidic ethanol with the pH of 2-5 to obtain a target product part. The gradient elution step not only ensures that the purity of the target product is high, but also ensures that the chromatographic column is continuously regenerated and can be recycled.

Preferably, the eluent obtained by the concentration in the step 3) is concentrated to 50 ℃, the relative density measured when the eluent is concentrated to 1.05-1.25, and the eluent is injected into a decoloring and desensitizing tank while the eluent is hot. Further preferably, step 3) of the present invention further comprises a step of recovering ethanol in the eluate.

Preferably, the activated carbon in step 3) of the present invention is in the form of powder or granules with a particle size of less than 0.5mm, and is imported or made from activated carbon for decolorization and desensitization or products thereof.

Preferably, the input amount of the activated carbon in the decolorizing and desensitizing tank in the step 3) is 0.2-0.5% of the total content (W/W) of CBD. Further preferably, the decolorizing and desensitizing step in the step 3) is completed by stirring at 45-75 ℃ for 0.5-1 h. The step 3) of the invention also comprises the filtration of the CBD concentrated solution for decolorizing and desensitizing, and the decolorizing and desensitizing device is a titanium rod filter with 500-800 meshes.

In an exemplary embodiment of the present invention, the step 3) is: concentrating the elution section rich in CBD to 50 ℃, measuring the relative density of the elution section to be 1.05-1.25, pumping the elution section into a decoloring tank while the elution section is hot, adding powdery activated carbon powder with the total content of CBD of 0.2-0.5% (W/W), stirring for 0.5-1 h at 45-75 ℃, and performing filter pressing through a titanium rod filter to obtain a decoloration desensitization CBD stock solution.

Preferably, the specific solvent in step 4) of the present invention refers to one or more than one of butane, pentane, hexane, heptane, ethyl acetate and ethanol in different proportions. Further preferred solvents are hexane, heptane, ethyl acetate, acetone and ethanol. The ethanol herein refers to an ethanol-water (or acetone-water) system, and the crystal concentration is 5 to 65% (V/V), more preferably 10 to 25%.

Preferably, the temperature for supersaturating and dissolving the specific solvent in step 4) of the present invention is 10 to 80 ℃, and may be, for example, 10 ℃, 10.1 ℃, 10.5 ℃, 10.7 ℃, 11 ℃, 12 ℃, 15 ℃, 18 ℃, 20 ℃, 23 ℃, 25 ℃, 26 ℃, 29 ℃, 30 ℃, 35 ℃, 37 ℃, 40 ℃, 40.5 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃ and 80 ℃; further preferably 20-60 ℃; more preferably 30 to 50 ℃.

In a preferred embodiment of the present invention, the step 4) is: concentrating the CBD de-coloring and desensitizing stock solution obtained in the step 3), measuring the relative density at 50 ℃ to be 1.05-1.35, recovering ethanol in the eluent, adding n-hexane at the temperature of 10-80 ℃ for supersaturation and dissolution, slowly stirring, and incubating for 36h to obtain crystal particles.

Preferably, the alcohol concentration of the washed crystal in the step 4) is 0-40% (V/V), and more preferably 5-15% (V/V).

Preferably, the washing temperature in step 4) of the present invention is 0 to 24 ℃, for example, 0 ℃, 0.1 ℃, 0.5 ℃, 0.8 ℃, 1.0 ℃, 1.5 ℃, 2.0 ℃,2.5 ℃, 3 ℃, 4 ℃, 5 ℃, 6 ℃, 7.0 ℃, 8 ℃, 9 ℃, 10 ℃, 11 ℃, 13 ℃, 15 ℃, 17 ℃, 19 ℃, 20 ℃, 24 ℃ and the like; further preferably 5-20 ℃; more preferably 10 to 15 ℃.

In an exemplary embodiment of the present invention, the step 4) is: and (3) adding purified water or 5-40% (V/V) ethanol into the crystal at the temperature of 0-24 ℃ for washing to obtain a primary product.

Preferably, the drying manner in step 4) of the present invention includes, but is not limited to, one or more of spray drying, vacuum drying, freeze drying, near infrared drying, and microwave drying.

Preferably, the temperature for drying in step 4) of the present invention is not more than 65 ℃.

Further preferably, the step 9) of the present invention further comprises the step of pulverizing the obtained cannabidiol into powder; the crushing mode comprises steam flow crushing and/or freezing crushing; the temperature of the crushed material does not exceed 65 ℃.

In a preferred embodiment of the present invention, there is provided a method for extracting cannabidiol from cannabis, comprising the steps of:

1) crushing the leaves of the hemp to 10-80 meshes to obtain medicinal powder;

2) extracting the medicinal material powder for 1-3 times by adopting 30-100% (V/V) ethanol 4-10 times of the medicinal material amount to obtain an extracting solution;

concentrating the extracting solution under reduced pressure until no alcohol smell exists, measuring the relative density at 50 ℃ to be 1.05-1.35, adding purified water in an amount which is 1/20 times of the amount of the medicinal materials, and reacting for 1-3 hours under normal pressure to obtain a fluid extract;

3) dispersing the fluid extract with purified water 1-10 times of the amount of the medicinal materials, adding acid to adjust the pH to 3.5-6.5, performing water precipitation for l-48 h at the temperature of 0-20 ℃, and removing impurities to obtain a water precipitation solution;

centrifuging the water precipitation solution, and adding 10-100% (V/V) ethanol into the precipitate obtained by centrifuging to dissolve the precipitate to obtain an alcohol solution of the precipitate;

subjecting the alcohol solution of the precipitate to column chromatography, wherein the column chromatography filler is alkali No. 4, alkali No. DKx4, Shanghai 763^#、^#702 weak base resin, one or more of D301, D303, D380, D301K and macroporous weak base resin, and the specific steps comprise: eluting with 0-60% (V/V) ethanol to remove impurities, eluting with 60-80% (V/V) ethanol to obtain a target product part, and eluting with 90-95% (V/V) ethanol to regenerate the chromatographic column;

Concentrating the concentrated eluent under reduced pressure to the density of 1.05-1.25 (the alcoholic strength is 40-70%), putting the concentrated eluent into a decoloring tank, adding active carbon according to 0.2-0.5% of the CBD content (W/W), stirring for 30min at 45-75 ℃, and filtering to obtain decoloring and desensitizing liquid for removing heat sources;

4) concentrating the obtained eluent under reduced pressure until the relative density measured at 50 ℃ is 1.05-1.35, recovering ethanol in the eluent, adding a certain specific solvent at the temperature of 10-80 ℃ for supersaturated dissolution, placing clear liquid in a crystallization tank, incubating at-10-20 ℃ for 12-72 hours, and filtering to obtain crystals;

adding purified water or 5-40% (V/V) ethanol into the crystal at the temperature of 0-24 ℃ for washing to obtain a primary product;

drying the primary product in the step 4) at the temperature of 40-55 ℃, and then crushing to obtain a cannabidiol finished product.

It should be noted that, in the present application, the descriptions of "4-8 times of the amount of the medicinal material" or "1/10-1/100 times of the amount of the medicinal material" and the like refer to that the volume of the solvent such as ethanol or water is 2-8 times or 1-10 times of the mass of the medicinal material, for example, 1g of the medicinal material powder, and 2 ml-8 ml of the ethanol as the extraction solvent.

According to the invention, Cannabidiol (CBD) is extracted from cannabis sativa, and in the continuous amplification of the original process, the process route is gradually optimized, so that the yield, the purity and the crystal form of Cannabidiol (CBD) are obviously improved, and particularly, the dynamic crystallization process is more suitable for large-scale production, and the physical characteristics of the obtained crystal are relatively better, thereby being beneficial to the development of subsequent preparations; in addition, the finally obtained CBD raw material can meet the requirement of injection grade, and the scope of modern application is extended.

The raw materials and reagents used in the method for extracting cannabidiol from cannabis sativa provided by the invention are all available in the market. The invention is further illustrated by the following examples: