Plant polysaccharide extract as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of pharmaceutic adjuvants, and particularly relates to a plant polysaccharide extract as well as a preparation method and application thereof. According to the method, pretreatment is carried out through the composite acid liquor composed of acetic acid and oxalic acid, meanwhile, efficient extraction is carried out through the deep-eutectic solvent, and impurity removal treatment is carried out in cooperation with modified activated carbon, so that the plant polysaccharide extract is efficiently obtained, and the extraction rate and purity of the extract are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of pharmaceutical excipients, and particularly relates to a plant polysaccharide extract and a preparation method and application thereof. Background Art

[0002] Polysaccharides generally refer to macromolecules composed of 10 or more monosaccharides connected by glycosidic bonds. They are widely found in the grains, fruits and vegetables, edible fungi and Chinese herbal medicines that people eat daily. Due to their many health and pharmacological functions, food-derived polysaccharides have gradually become a hot topic in natural product research in recent decades, and have now been applied to research and applications in the fields of food, beverages, medicine and cosmetics. Plant resources are an important foundation for human survival and development, among which edible plants and medicinal plants are the most important plant resources in our daily lives. With the rapid development of traditional Chinese medicine and health foods in recent years, a large number of plant sources, especially the active substances and efficacy of Chinese herbal medicines, have been studied more deeply, among which plant polysaccharides have been studied most extensively. The principle of extracting plant polysaccharides is basically to obtain polysaccharides by destroying cells to release the contents.

[0003] A Chinese patent (publication number CN116874633A) discloses a method for extracting polysaccharides from rhizomes of polygonatum sibiricum plants, and the extraction method of the invention comprises: preparing a mixed solution a by mixing dried and crushed rhizomes of polygonatum sibiricum plants and a water-containing low eutectic solvent, subjecting the mixed solution a to ultrasonic-assisted extraction to obtain a polysaccharide extract, separating the low eutectic solvent in the obtained polysaccharide extract to obtain a crude polysaccharide solution b, removing impurities and purifying the obtained crude polysaccharide extract b to obtain a crude polysaccharide solution c, dialysis and concentrating the obtained crude polysaccharide extract c to obtain a pure polysaccharide extract, and freeze-drying the obtained pure polysaccharide solution to obtain polysaccharides from rhizomes of polygonatum sibiricum plants. However, when extracting plant polysaccharides in the prior art, there is still the problem that the extraction rate and purity of the plant polysaccharide extract are not high.

[0004] Therefore, how to pre-treat the plant raw materials, select suitable extraction solvents, and introduce activated carbon for impurity removal to achieve efficient acquisition of plant polysaccharide extracts and improve the extraction rate and purity of the extracts has become a direction that needs to be focused on. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a plant polysaccharide extract and a preparation method and application thereof, aiming to solve the problem of low extraction rate and purity of the plant polysaccharide extract when extracting plant polysaccharides in the prior art.

[0006] The present invention uses acetic acid and oxalic acid to form a composite acid solution for pretreatment, uses a low eutectic solvent for efficient extraction, and uses modified activated carbon for impurity removal, so as to achieve efficient acquisition of plant polysaccharide extracts and improve the extraction rate and purity of the extracts.

[0007] The technical solution adopted by the present invention to solve the above technical problems is as follows:

[0008] The first aspect of the present invention provides a method for preparing a plant polysaccharide extract, comprising the following steps:

[0009] Step S1: Slice the plant and dry it, grind it with a pulverizer, and then sieve it to obtain plant powder;

[0010] Step S2: by weight, 80 to 90 parts of an acid compound and 900 to 1000 parts of deionized water are mixed evenly to form a composite acid solution, and then 200 to 300 parts of plant powder are added to perform pretreatment to obtain pretreated plant powder;

[0011] Step S3: adding 200 to 300 parts of the pretreated plant powder into 5000 to 6000 parts of a low eutectic solvent for extraction treatment to obtain an extract A;

[0012] Step S4: adding 40 to 50 parts of the extract A into 900 to 1000 parts of deionized water to fully dissolve, and then adding 10 to 20 parts of modified activated carbon to remove impurities, thereby obtaining a plant polysaccharide extract;

[0013] The preparation method of the modified activated carbon comprises: adding 16 to 20 parts of ferric chloride to 100 to 120 parts of deionized water by weight to fully dissolve the mixture, and then adding 4 to 8 parts of activated carbon for modification to obtain the modified activated carbon.

[0014] As a preferred technical solution of the present invention, the plant is Polygonatum sibiricum.

[0015] As a preferred technical solution of the present invention, the acid compounds are acetic acid and oxalic acid; the mass ratio of acetic acid to oxalic acid in the acid compounds is (1-2):1.

[0016] As a preferred technical solution of the present invention, the pretreatment conditions include: stirring at a speed of 80-100 r / min for 40-60 min, then heating to 80-90° C. and keeping warm for 10-20 min, distilling under reduced pressure, and drying.

[0017] Acetic acid in the composite acid solution, as a weak acid, can penetrate the cell wall and weaken the hydrogen bond network of cellulose and hemicellulose through protonation. Oxalic acid, as a strong acid chelating agent, can dissolve calcium bridges in plant cell walls and destroy the rigid structure of cell walls. The two work together to destroy the cross-linked structure of cell wall polysaccharides and accelerate the release of polysaccharides. If the amount of oxalic acid in the composite acid solution is too little, it will not be able to effectively destroy the rigid structure of the cell wall, resulting in a decrease in the polysaccharide extraction rate; if the amount of oxalic acid is too much, the metal ion content in the extract is high, and there are more impurities in the final extract.

[0018] As a preferred technical solution of the present invention, the preparation method of the low eutectic solvent comprises: mixing 1000 to 1200 parts of choline chloride and 900 to 1000 parts of urea in parts by weight, and then adding 800 to 900 parts of deionized water and mixing evenly to obtain a low eutectic solvent.

[0019] As a preferred technical solution of the present invention, the extraction treatment conditions include: ultrasonic extraction at 50-60°C for 60-80 minutes, centrifugal separation at a speed of 5000-6000 r / min for 20-30 minutes, collecting the precipitate, and freeze-drying.

[0020] Choline chloride is a common hydrogen bond acceptor, while urea is a hydrogen bond donor. The two interact through hydrogen bonds to form a low eutectic solvent. During the extraction of plant polysaccharides, urea can break the hydrogen bond network of cellulose and hemicellulose, and the quaternary ammonium structure of choline chloride can enhance solvent permeability and promote the release of cell contents. The combined effect improves the extraction efficiency of plant polysaccharides.

[0021] As a preferred technical solution of the present invention, the modification treatment conditions include: adjusting the pH to 7.6-7.8 with sodium hydroxide solution, stirring the reaction at a speed of 140-160 r / min for 24-28 hours, filtering, washing with water, and drying.

[0022] As a preferred technical solution of the present invention, the conditions for the impurity removal treatment include: keeping warm at 50-54° C. for 50-60 minutes, filtering, and freeze-drying.

[0023] The activated carbon in the modified activated carbon itself has a developed pore structure and a large specific surface area, which can provide a large number of adsorption sites, and the pigments in the plant polysaccharide extract have an aromatic ring structure, which can form a π-π conjugation effect with the π electron system on the surface of the activated carbon; at the same time, the surface of nano-hydroxy iron is rich in hydroxyl functional groups, which can form coordination bonds with the metal impurity ions introduced after oxalic acid treatment through hydroxyl groups. In addition, it can also use electrostatic effects to attract charged metal ions, thereby achieving efficient adsorption and effectively improving the purity of plant polysaccharide extracts.

[0024] The second aspect of the present invention provides a plant polysaccharide extract prepared by the method described in the first aspect.

[0025] The third aspect of the present invention provides a use of the plant polysaccharide extract prepared by the method described in the first aspect in a pharmaceutical excipient.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention first pre-treats plant powder with a composite acid solution, and acetic acid and oxalic acid synergistically destroy the cross-linked structure of cell wall polysaccharides and accelerate the release of polysaccharides. Subsequently, choline chloride and urea are used to form a low eutectic solvent to achieve efficient extraction of plant polysaccharides. Finally, modified activated carbon is used to adsorb charged metal impurities introduced by oxalic acid chelation. The combined effect improves the extraction efficiency of plant polysaccharides.

[0028] (2) The acetic acid in the composite acid solution of the present invention, as a weak acid, can penetrate the cell wall and weaken the hydrogen bond network of cellulose and hemicellulose through protonation. The oxalic acid, as a strong acid chelating agent, can dissolve the calcium bridges in the plant cell wall and destroy the rigid structure of the cell wall. The two synergistically destroy the cross-linked structure of the cell wall polysaccharide and accelerate the release of the polysaccharide.

[0029] (3) In the low eutectic solvent of the present invention, choline chloride is a common hydrogen bond acceptor, while urea is a hydrogen bond donor. The low eutectic solvent formed by the interaction of the two through hydrogen bonds can break the hydrogen bond network of cellulose and hemicellulose during the extraction of plant polysaccharides. The quaternary ammonium structure of choline chloride can enhance the solvent permeability and promote the release of cell contents. The combined effect improves the extraction efficiency of plant polysaccharides.

[0030] (4) The activated carbon in the modified activated carbon of the present invention has a well-developed pore structure and a large specific surface area, which can provide a large number of adsorption sites. The introduced nano-hydroxy iron can undergo π-π conjugation with pigment molecules, etc., and can also provide specific binding sites for charged metal impurities introduced after oxalic acid treatment, thereby achieving efficient adsorption and effectively improving the purity of plant polysaccharide extracts. DETAILED DESCRIPTION

[0031] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0032] The sources of some components in the embodiments and comparative examples are as follows:

[0033] Acetic acid, CAS No. 64-19-7, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0034] Oxalic acid, CAS No. 6153-56-6, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0035] Choline chloride, CAS No. 67-48-1, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0036] Urea, CAS No. 57-13-6, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0037] Commercially available activated carbon, product number C112241, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0038] Ferric chloride, CAS No. 7705-08-0, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0039] Sodium hydroxide, CAS No. 1310-73-2, was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0040] Example 1

[0041] This embodiment provides a method for preparing a plant polysaccharide extract, comprising the following steps:

[0042] Step S1: Slice the polygonatum sibiricum and dry it, grind it with a pulverizer, and then sieve it to obtain the polygonatum sibiricum powder;

[0043] Step S2: In parts by weight, 90 parts of an acid compound (60 parts of acetic acid and 30 parts of oxalic acid) and 1000 parts of deionized water are mixed evenly to form a composite acid solution, and then 300 parts of plant polygonatum sibiricum powder are added for pretreatment, first stirred at a speed of 100 r / min for 40 minutes, then heated to 90° C. and kept warm for 10 minutes, distilled under reduced pressure, and dried to obtain the pretreated plant polygonatum sibiricum powder;

[0044] Step S3: adding 300 parts of the pretreated plant polygonatum powder into 6000 parts of a low eutectic solvent for extraction, performing ultrasonic extraction at 60° C. for 60 min, centrifuging at 6000 r / min for 20 min, collecting the precipitate, and freeze-drying to obtain extract A;

[0045] Step S4: adding 50 parts of the extract A into 1000 parts of deionized water to fully dissolve, then adding 20 parts of modified activated carbon for impurity removal, keeping warm at 54° C. for 50 minutes, filtering, and freeze-drying to obtain a plant polysaccharide extract;

[0046] Preparation of the modified activated carbon: by weight, 20 parts of ferric chloride are added to 120 parts of deionized water to fully dissolve, and then 8 parts of activated carbon are added for modification, the pH is adjusted to 7.8 with sodium hydroxide solution, the reaction is stirred at a speed of 160r / min for 24h, filtered, washed with water, and dried to obtain the modified activated carbon.

[0047] Preparation of the low eutectic solvent: In parts by weight, 1200 parts of choline chloride and 1000 parts of urea are mixed, and then 900 parts of deionized water are added and mixed uniformly to obtain a low eutectic solvent.

[0048] Example 2

[0049] This embodiment provides a method for preparing a plant polysaccharide extract, comprising the following steps:

[0050] Step S1: Slice the polygonatum sibiricum and dry it, grind it with a pulverizer, and then sieve it to obtain the polygonatum sibiricum powder;

[0051] Step S2: In parts by weight, 80 parts of an acid compound (40 parts of acetic acid and 40 parts of oxalic acid) and 900 parts of deionized water are mixed evenly to form a composite acid solution, and then 200 parts of plant polygonatum sibiricum powder are added for pretreatment, first stirred at a speed of 80 r / min for 60 min, then heated to 80° C. and kept warm for 20 min, distilled under reduced pressure, and dried to obtain the pretreated plant polygonatum sibiricum powder;

[0052] Step S3: adding 200 parts of the pretreated plant polygonatum powder into 5000 parts of a low eutectic solvent for extraction, performing ultrasonic extraction at 50° C. for 80 min, centrifuging at 5000 r / min for 30 min, collecting the precipitate, and freeze-drying to obtain extract A;

[0053] Step S4: adding 40 parts of the extract A into 900 parts of deionized water to fully dissolve, then adding 10 parts of modified activated carbon for impurity removal, keeping warm at 50° C. for 60 minutes, filtering, and freeze-drying to obtain a plant polysaccharide extract;

[0054] Preparation of the modified activated carbon: by weight, 16 parts of ferric chloride are added to 100 parts of deionized water to fully dissolve, and then 4 parts of activated carbon are added for modification, the pH is adjusted to 7.6 with sodium hydroxide solution, the reaction is stirred at a speed of 140r / min for 28h, filtered, washed with water, and dried to obtain the modified activated carbon.

[0055] Preparation of the low eutectic solvent: In parts by weight, 1000 parts of choline chloride and 900 parts of urea are mixed, and then 800 parts of deionized water are added and mixed uniformly to obtain a low eutectic solvent.

[0056] Example 3

[0057] This embodiment provides a method for preparing a plant polysaccharide extract, comprising the following steps:

[0058] Step S1: Slice the polygonatum sibiricum and dry it, grind it with a pulverizer, and then sieve it to obtain the polygonatum sibiricum powder;

[0059] Step S2: In parts by weight, 85 parts of an acid compound (55 parts of acetic acid and 30 parts of oxalic acid) and 950 parts of deionized water are mixed evenly to form a composite acid solution, and then 250 parts of plant polygonatum sibiricum powder are added for pretreatment, first stirred at a speed of 90 r / min for 50 min, then heated to 85° C. and kept warm for 15 min, distilled under reduced pressure, and dried to obtain the pretreated plant polygonatum sibiricum powder;

[0060] Step S3: adding 250 parts of the pretreated Polygonatum sibiricum powder to 5500 parts of a low eutectic solvent for extraction, performing ultrasonic extraction at 55° C. for 70 min, centrifuging at 5500 r / min for 25 min, collecting the precipitate, and freeze-drying to obtain an extract A;

[0061] Step S4: adding 45 parts of the extract A to 950 parts of deionized water to fully dissolve, then adding 15 parts of modified activated carbon for impurity removal, keeping warm at 52° C. for 55 minutes, filtering, and freeze-drying to obtain a plant polysaccharide extract;

[0062] Preparation of the modified activated carbon: by weight, 18 parts of ferric chloride are added to 110 parts of deionized water to fully dissolve, and then 6 parts of activated carbon are added for modification, the pH is adjusted to 7.7 with sodium hydroxide solution, the reaction is stirred at a speed of 150r / min for 26h, filtered, washed with water, and dried to obtain the modified activated carbon.

[0063] Preparation of the low eutectic solvent: In parts by weight, 1100 parts of choline chloride and 950 parts of urea are mixed, and then 850 parts of deionized water are added and mixed uniformly to obtain a low eutectic solvent.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 1 is that no composite acid solution is used for pretreatment.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 1 is that the amount of acetic acid in the acid compound is changed to 80 parts, and the amount of oxalic acid is changed to 10 parts.

[0068] Comparative Example 3

[0069] The difference between this comparative example and Example 1 is that the amount of acetic acid in the acid compound is changed to 30 parts, and the amount of oxalic acid is changed to 60 parts.

[0070] Comparative Example 4

[0071] The difference between this comparative example and Example 1 is that deionized water is used instead of the low eutectic solvent for extraction treatment.

[0072] Comparative Example 5

[0073] The difference between this comparative example and Example 1 is that commercially available activated carbon (Product No. C112241) is used instead of modified activated carbon for impurity removal treatment.

[0074] The performance of the plant polysaccharide extracts provided in the above embodiments and comparative examples was tested, and the extraction rate and purity were tested using the phenol-sulfuric acid method.

[0075] The above performance test data is shown in Table 1.

[0076] Table 1 Performance test results

[0077] Extraction rate (%) purity(%) Example 1 32.61 53.16 Example 2 30.95 52.67 Example 3 31.78 52.04 Comparative Example 1 21.52 49.84 Comparative Example 2 25.86 48.27 Comparative Example 3 29.24 33.82 Comparative Example 4 20.74 48.95 Comparative Example 5 29.41 31.48

[0078] From the above content, it can be seen that the present invention uses acetic acid and oxalic acid to form a composite acid solution for pretreatment, and at the same time uses a low eutectic solvent for efficient extraction, and cooperates with modified activated carbon for impurity removal treatment to achieve efficient acquisition of plant polysaccharide extracts (Examples 1 to 3), with an extraction rate of 30.95-32.61% and a purity of 52.04-53.16%.

[0079] Compared with Example 1, if the composite acid solution is not used for pretreatment, the extraction rate is reduced (Comparative Example 1); compared with Example 1, the amount of acetic acid in the acid compound is changed to 80 parts, and the amount of oxalic acid is changed to 10 parts, then the amount of oxalic acid is too little, and the rigid structure of the cell wall cannot be effectively destroyed, resulting in a decrease in the polysaccharide extraction rate (Comparative Example 2); compared with Example 1, the amount of acetic acid in the acid compound is changed to 30 parts, and the amount of oxalic acid is changed to 60 parts, then the amount of oxalic acid is too much, the metal ion content in the extract is high, and the purity of the final extract is reduced (Comparative Example 3); compared with Example 1, deionized water is used instead of a low eutectic solvent for extraction treatment, and the extraction rate is reduced (Comparative Example 4); compared with Example 1, commercially available activated carbon (Product No. C112241) is used instead of modified activated carbon for impurity removal treatment, and the purity is reduced (Comparative Example 5).

[0080] In summary, the present invention uses acetic acid and oxalic acid to form a composite acid solution for pretreatment, and uses a low eutectic solvent for efficient extraction, and uses modified activated carbon for impurity removal, so as to achieve efficient acquisition of plant polysaccharide extracts and improve the extraction rate and purity of the extracts.

Claims

1. A method for preparing a plant polysaccharide extract, It is characterized in that The following steps are involved: Step S1: Slice the plant and dry it, grind it with a pulverizer, and then sieve it to obtain plant powder; Step S2: by weight, 80 to 90 parts of an acid compound and 900 to 1000 parts of deionized water are mixed evenly to form a composite acid solution, and then 200 to 300 parts of plant powder are added to perform pretreatment to obtain pretreated plant powder; Step S3: adding 200 to 300 parts of the pretreated plant powder into 5000 to 6000 parts of a low eutectic solvent for extraction treatment to obtain an extract A; Step S4: adding 40 to 50 parts of the extract A into 900 to 1000 parts of deionized water to fully dissolve, and then adding 10 to 20 parts of modified activated carbon to remove impurities, thereby obtaining a plant polysaccharide extract; The preparation method of the modified activated carbon comprises: adding 16 to 20 parts of ferric chloride to 100 to 120 parts of deionized water by weight to fully dissolve the mixture, and then adding 4 to 8 parts of activated carbon for modification to obtain the modified activated carbon.

2. The method for preparing a plant polysaccharide extract according to claim 1, characterized in that: The plant is Polygonatum sibiricum.

3. The method for preparing a plant polysaccharide extract according to claim 1, characterized in that: The acid compounds are acetic acid and oxalic acid; the mass ratio of acetic acid to oxalic acid in the acid compounds is (1-2):

1.

4. The method for preparing a plant polysaccharide extract according to claim 1, characterized in that: The pretreatment conditions include: stirring at a speed of 80 to 100 r / min for 40 to 60 minutes, then heating to 80 to 90° C. and keeping the temperature for 10 to 20 minutes, distilling under reduced pressure, and drying.

5. The method for preparing a plant polysaccharide extract according to claim 1, characterized in that: The preparation method of the low eutectic solvent comprises: mixing 1000-1200 parts of choline chloride and 900-1000 parts of urea by weight, and then adding 800-900 parts of deionized water and mixing evenly to obtain the low eutectic solvent.

6. The method for preparing a plant polysaccharide extract according to claim 1, characterized in that: The extraction treatment conditions include: ultrasonic extraction at 50-60° C. for 60-80 min, centrifugal separation at a speed of 5000-6000 r / min for 20-30 min, collecting precipitates, and freeze-drying.

7. The method for preparing a plant polysaccharide extract according to claim 1, characterized in that: The modification treatment conditions include: adjusting the pH to 7.6-7.8 with sodium hydroxide solution, stirring the reaction at a speed of 140-160 r / min for 24-28 hours, filtering, washing with water, and drying.

8. The method for preparing a plant polysaccharide extract according to claim 1, characterized in that: The impurity removal treatment conditions include: keeping warm at 50-54° C. for 50-60 minutes, filtering, and freeze-drying.

9. A plant polysaccharide extract, characterized in that: The method is obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the plant polysaccharide extract obtained by the preparation method according to any one of claims 1 to 8 in pharmaceutical excipients.