Polygonatum sibiricum flavone extraction method and obtained product

Abstract

The invention provides a polygonatum sibiricum flavone extraction method, which comprises pretreatment and extraction operations: S1, pretreatment: polygonatum sibiricum is sliced, dried and crushed, and extruded and puffed by a screw extruder; s2, extracting: extracting the rhizoma polygonati puffed material obtained in the step S1 by using an organic solvent, wherein the organic solvent is an ethanol water solution with the mass fraction of 50-80%. The invention provides an extraction method of polygonatum sibiricum flavone, and aims to provide a pretreatment technology for extracting the polygonatum sibiricum flavone, so that plant cell walls can be thoroughly broken, and the extraction rate of the polygonatum sibiricum flavone is improved.

Description

Technical Field

[0001] The invention belongs to the field of separation technology, and specifically relates to a method for extracting flavonoids from plant rhizomes, and the obtained products. Background Art

[0002] As one of the traditional Chinese medicines, Polygonatum odoratum is rich in resources and widely distributed. There are more than 30 different species, which have the effects of replenishing qi and nourishing yin, moistening the lungs, strengthening the spleen and benefiting the kidneys. Studies have shown that Polygonatum odoratum is rich in polysaccharides, flavonoids and other active ingredients, among which flavonoids have anti-inflammatory, antiviral and cardiovascular protection effects, and show strong antioxidant activity.

[0003] At present, the research on polygonatum at home and abroad mainly includes the analysis and research of its various active ingredients (determination of the content of total flavonoids and total phenols in polygonatum, Chen Keke et al., Shaanxi Agricultural Science, 2012), and the research on the extraction process of flavonoids in polygonatum is relatively small. Pretreatment is the link of treating the plant raw materials first in the process of plant component extraction, and pretreatment will affect the extraction effect of plant components. At present, in the operation of extracting flavonoids from polygonatum, the raw materials of polygonatum are usually mechanically crushed. This preliminary treatment is simple and convenient, but there are problems such as insufficient cell crushing and uneven crushing, resulting in large solvent consumption and energy consumption in the extraction stage, low extraction efficiency, and unstable production. Patent CN116211959A proposes a pretreatment method for improving the extraction amount of polysaccharides and total flavonoids in polygonatum, and the pretreatment method is to irradiate polygonatum with electron beams. The operation of electron beam irradiation has high requirements on equipment and operation, resulting in more difficult operation. The current extraction process level of polygonatum flavonoids needs to be improved, and the extraction efficiency also needs to be improved to better develop and apply polygonatum resources.

[0004] Therefore, in order to overcome the current processing bottleneck in the pretreatment process, improve the extraction rate of Polygonatum sibiricum flavonoids, and maximize the potential economic value of Polygonatum sibiricum, it is necessary to develop an efficient, fast and low-cost pretreatment technology. This will not only help the extraction of Polygonatum sibiricum flavonoids, but also provide a reliable theoretical reference and experience for the subsequent extraction of other plant components. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to propose a method for extracting flavonoids from polygonatum, provide a pretreatment technology for polygonatum, and improve the extraction rate of flavonoids from polygonatum.

[0006] The second object of the present invention is to provide the product obtained by the extraction method.

[0007] The technical solution for achieving the above-mentioned purpose of the present invention is:

[0008] A method for extracting flavonoids from polygonatum sibiricum, comprising the operations of pretreatment and extraction:

[0009] S1 pretreatment: slicing, drying and crushing of polygonatum, extrusion and expansion;

[0010] S2 extraction: extracting the expanded polygonatum material obtained in step S1 with an organic solvent, wherein the organic solvent is an ethanol aqueous solution with a mass fraction of 50-80%.

[0011] The main purpose of pretreatment is to destroy the plant cell wall and cell structure, increase the material porosity and contact surface area, reduce the resistance of the active ingredients to diffuse outward, so that the active ingredients are more easily dissolved, thereby improving the extraction rate and purity of the plant active ingredients. It also provides a reliable basis for subsequent experimental research.

[0012] Wherein, the preprocessing comprises the steps of:

[0013] S11: Slice the rhizome of Polygonatum cyrtonema and dry it at a temperature of 50-70° C. until the moisture content is less than 10%;

[0014] S12: crushing the dried polygonatum slices into 40-100 meshes and storing them away from light (long-term exposure to light will cause oxidative decomposition of polygonatum flavonoids);

[0015] S13: placing the polygonatum powder in a screw extruder for extrusion and expansion to obtain a polygonatum expanded material; the screw extrusion and expansion parameters are as follows: screw speed 300-400rpm, moisture content 20-35%, extrusion temperature 90-115°C, die hole diameter 6-10mm.

[0016] The extraction operation is as follows:

[0017] The expanded polygonatum material is subjected to flavonoid extraction by a water bath method, and then filtered and cooled to obtain a polygonatum flavonoid extract; the extraction parameters are as follows: the organic solvent is an ethanol aqueous solution with a mass fraction of 60-80%, the extraction temperature is 60-80°C, the material-liquid ratio is 1:15-25 (g / mL), and the extraction time is 0.5-2h.

[0018] Wherein, the polygonatum is fresh polygonatum, and / or,

[0019] In step S11, the rhizome of Polygonatum sibiricum is sliced ​​into a thickness of 1 to 2 mm and dried in a drying oven at 50 to 70° C. until the moisture content is less than 10%.

[0020] Wherein, in step S13, water is added to the material to control the moisture content to be 23-27% (the ratio of the mass of moisture to the mass of the material), and the extrusion temperature of the screw extruder is 95-100°C.

[0021] After the material comes out of the die holes of the template, the moisture in the material will turn into water vapor, making the material loose and porous.

[0022] Furthermore, the screw extruder is a single screw extruder, and the screw extrusion expansion parameters are: screw speed 300-350rpm, die hole diameter 8-10mm.

[0023] Another preferred technical solution of the present invention is that in step S2, the organic solvent is an ethanol aqueous solution with a mass fraction of 65-75%, the extraction temperature is 78-82°C, and the extraction temperature is controlled by a water bath.

[0024] Furthermore, in step S2, the material-liquid ratio is 1:15-16 (g / mL), and the extraction time is 1.3-1.5 h; after extraction, the reaction mixture is filtered and cooled to obtain the polygonatum flavonoids extract.

[0025] Further preferably, two filtrations can be performed in step S2. Since the cells of Polygonatum sibiricum are fully broken after extrusion and expansion, tiny impurities are dissolved and mixed with the target molecules, making them difficult to separate. Better filtration can avoid turbidity of the Polygonatum sibiricum flavonoid extract and affect the determination of flavonoid content. The extraction process requires stirring, and to prevent ethanol from volatilizing, the mouth of the flask is sealed with a sealing film.

[0026] Wherein, after extraction, the reaction mixture is filtered twice, the filter medium of the first filtration is gauze, and the second filtration is filter paper.

[0027] The polygonatum flavonoids obtained by the extraction method of the invention.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The method for extracting polygonatum flavonoids proposed by the invention aims to provide a pretreatment technology for extracting polygonatum flavonoids, which can completely break plant cell walls and improve the extraction rate of polygonatum flavonoids.

[0030] The pretreatment method for improving the extraction rate of flavonoids from polygonatum adopts extrusion puffing to pretreat polygonatum, extrusion shearing and friction of the material, and the temperature and pressure in the barrel gradually increase. When the material is extruded from the die hole of the template, the high pressure instantly changes to normal pressure. The sudden decrease in pressure will cause the water in the material to evaporate suddenly from the material, making the material porous and loose. Therefore, extrusion puffing can cause the cell wall of the material to be broken and loose, increase the gap between the particles of the material, improve the permeability of the extraction solvent, enhance the mass transfer force, and facilitate the rapid dissolution of the effective components in the plant cells. Compared with the traditional mechanical crushing treatment, the extraction rate of flavonoids from polygonatum is greatly improved.

[0031] The method for extracting polygonatum flavonoids has the advantages of high production efficiency, low cost, low consumption, suitability for industrial production, and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of a screw extruder.

[0033] Figure 2 This is a schematic diagram of the local structure of a screw extruder.

[0034] In the figure, 1 is a mold plate, 2 is a mold hole, 3 is a screw, and 4 is a barrel.

[0035] Figure 3 This is the standard curve of rutin.

[0036] Figure 4 This is a comparison chart of the flavonoids content of Polygonatum sibiricum extracted from Experimental Examples 1 to 3.

[0037] Figure 5 This is a comparison chart of the flavonoids content of Polygonatum sibiricum extracted from Examples 1 to 4. DETAILED DESCRIPTION

[0038] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0039] Unless otherwise specified, the test materials and testing instruments used in the instructions can be purchased commercially.

[0040] Determination of flavonoid content in Polygonatum sibiricum: Pipette 1mL Polygonatum sibiricum extract into a 25mL volumetric flask, add 1mL 5% NaNO2 solution, shake well and let stand for 6 minutes, then add 1mL 10% Al(NO3)3 solution, shake well and let stand for 6 minutes, finally add 10mL 4% NaOH solution, shake well and let stand for 15 minutes. Using the reagent blank group as a reference, measure the absorbance value at 510nm by UV-visible spectrophotometry, and then bring it into the rutin standard curve ( Figure 3 The flavonoid concentration was calculated using the regression equation obtained using the standard curve.

[0041] Extraction rate of total flavonoids from polygonatum (%) = C × V × N / m

[0042] C: Concentration of polygonatum flavonoids extract determined by rutin standard curve, mg / mL;

[0043] V: total volume of polygonatum flavonoids extract, mL;

[0044] N: solution dilution multiple;

[0045] m: mass of Polygonatum sibiricum powder, g.

[0046] The raw material Polygonatum sibiricum in the embodiment comes from Tongren County, Guizhou Province.

[0047] See also Figure 1 and Figure 2The screw extruder used in the embodiment adopts an integral equal-depth unequal-pitch design (single screw, equal screw groove depth, but unequal screw pitch), and the material is extruded by the screw 3 in the barrel 4. From the feeding to the discharging direction, there are the conveying section, the melting section (the melting section is the extrusion section) and the metering section. Among them, the temperature of the melting section is the highest, which has a significant impact on the material change. The temperature of the melting section is set as the extrusion temperature. Therefore, this study adjusts the extrusion temperature to improve the extraction effect. The die hole diameter is the diameter of the die hole 2 on the template 1. The template 1 is at the outlet of the screw extruder, and the Huangjing powder is extruded from this die hole. The size of the die hole 2 is adjustable.

[0048] Preliminary trials

[0049] In the pre-treatment of polygonatum sibiricum slices, the inventors tried a slice thickness of 1 to 4 mm and found that the thinner the slices, the shorter the drying time, the smaller the impact on the flavonoid content of polygonatum sibiricum, and the more complete and uniform the subsequent crushing, which is conducive to extrusion shearing. Therefore, the slice thickness was unified to 1 to 2 mm and the drying temperature was 50 to 70 ° C.

[0050] The reaction mixture obtained after extraction should be filtered. Because the cells are fully broken by the previous treatment, the tiny impurities are dissolved and mixed with the target molecules, and the reaction mixture is difficult to separate, so it is filtered twice, and through experimental comparison, it is determined that the filter medium for the first filtration is gauze, and the second filtration is filter paper. The obtained polygonatum flavonoids extract is clear and stable.

[0051] Test Example 1

[0052] (1) Wash and slice fresh rhizomes of Polygonatum cyrtonema into 1 mm thick slices, place in a drying oven at 60° C. and dry to constant weight, with a moisture content of 6-7%;

[0053] (2) Put the dried polygonatum slices into a grinder and grind them into 40 meshes to obtain polygonatum powder, which is then stored away from light;

[0054] (3) Extract flavonoids from polygonatum powder by water bath method, filter and cool to obtain polygonatum flavonoid extract. Extract flavonoids from polygonatum puffed material by water bath method, filter twice and cool to obtain polygonatum flavonoid extract. The extraction parameters are as follows: the organic solvent is 60% ethanol aqueous solution, the extraction temperature is 60°C, the material-liquid ratio is 1:15 (g / mL), and the extraction time is 1h;

[0055] The sodium nitrite-aluminum nitrate colorimetric method was used to determine the flavonoid content of Polygonatum sibiricum: 1 mL of Polygonatum sibiricum extract was taken into a 25 mL volumetric flask, 1 mL of 5% NaNO2 solution was added, and the mixture was shaken and allowed to stand for 6 minutes. Then 1 mL of 10% Al(NO3)3 solution was added, and the mixture was shaken and allowed to stand for 6 minutes. Finally, 10 mL of 4% NaOH solution was added, and the mixture was shaken and allowed to stand for 15 minutes. The absorbance value was measured at 510 nm by UV-visible spectrophotometry with the blank reagent as the reference, and the regression equation obtained by substituting the rutin standard curve (see Figure 3 ) was used to calculate the flavonoid concentration.

[0056] Test Example 2

[0057] The operation steps (1) to (2) are the same as those in Experiment 1.

[0058] (3) The flavonoids from the polygonatum powder were extracted by water bath method, filtered twice, and cooled to obtain the polygonatum flavonoids extract. The extraction parameters were as follows: the organic solvent was 70% ethanol, the extraction temperature was 70°C, the solid-liquid ratio was 1:20 (g / mL), and the extraction time was 1h.

[0059] Test Example 3

[0060] The operation steps (1) to (2) are the same as those in Experiment 1.

[0061] (3) The flavonoids from the polygonatum powder were extracted by water bath method, filtered twice, and cooled to obtain the polygonatum flavonoids extract. The extraction parameters were as follows: the organic solvent was 80% ethanol, the extraction temperature was 80°C, the solid-liquid ratio was 1:25 (g / mL), and the extraction time was 1.5h.

[0062] The content of flavonoids in the flavonoids extracts obtained in Experimental Examples 1 to 3 was determined by sodium nitrite-aluminum nitrate colorimetry. Figure 4 In the extraction stage of the material without screw extrusion, a higher material-liquid ratio, a higher temperature and a longer time can increase the flavonoid content. The inventors found through comparison that after pretreatment, a lower ethanol concentration (70%) can also achieve the same extraction effect as 80% ethanol, indicating that pretreatment can save organic solvents. Therefore, subsequent experiments used 70% ethanol aqueous solution for extraction.

[0063] Pretreatment is a crucial step in the process of plant component extraction, which directly affects the extraction effect of plant components. The inventors compared and optimized the pretreatment conditions to obtain the optimal screw extrusion parameters. The following are some experiments.

[0064] Embodiment 1:

[0065] (1) Wash and slice fresh rhizomes of Polygonatum cyrtonema into 1 mm thick slices, place in a drying oven at 60° C. and dry to constant weight, wherein the moisture content of the obtained Polygonatum cyrtonema slices is 6-7%;

[0066] (2) Put the dried Polygonatum sibiricum slices into a grinder and grind them into 40 mesh and store them away from light;

[0067] (3) placing the polygonatum powder in a screw extruder for extrusion pretreatment to obtain a polygonatum expanded material. The screw extrusion parameters are as follows: screw speed 300 rpm, adding water to the material to control the moisture content to 20%, extrusion temperature 90°C, die hole diameter 6 mm;

[0068] (4) The expanded polygonatum sibiricum material is placed in a drying oven at 60°C and dried to a constant weight, and then the expanded polygonatum sibiricum material is placed in a grinder and crushed into 40 meshes.

[0069] (5) The expanded material of Polygonatum sibiricum was subjected to flavonoid extraction by water bath method. After extraction, the reaction mixture was filtered twice, the first filtration was filtered with gauze, the second filtration was filtered with filter paper, and the Polygonatum sibiricum flavonoid extract was obtained by cooling. The extraction parameters were as follows: the organic solvent was an ethanol aqueous solution with a mass fraction of 70%, the extraction temperature was 70°C, the material-liquid ratio was 1:15 (g / mL), and the extraction time was 1h; stirring was required during the extraction process, and the mouth of the flask was sealed with a sealing film to prevent ethanol from volatilizing.

[0070] The sodium nitrite-aluminum nitrate colorimetric method was used to determine the flavonoids content in Polygonatum sibiricum.

[0071] Example 2

[0072] (1) Wash and slice fresh rhizomes of Polygonatum cyrtonema into 1 mm thick slices, place in a drying oven at 60° C. and dry to constant weight, with a moisture content of 6-7%;

[0073] (2) Put the dried Polygonatum sibiricum slices into a grinder and grind them into 40 mesh and store them away from light;

[0074] (3) placing the polygonatum powder in a screw extruder for extrusion expansion pretreatment to obtain a polygonatum expanded material. The screw extrusion expansion parameters are as follows: screw speed 350 rpm, moisture content 25%, extrusion temperature 100°C, die hole diameter 8 mm;

[0075] (4) drying the expanded Polygonatum sibiricum material in a drying oven at 60°C until constant weight, and then grinding it in a grinder to 40 mesh;

[0076] (5) Extract flavonoids from the expanded material of Polygonatum sibiricum by water bath method, filter twice, and cool to obtain a Polygonatum sibiricum flavonoid extract. The extraction parameters are as follows: the organic solvent is 70% ethanol, the extraction temperature is 70°C, the material-liquid ratio is 1:15 (g / mL), and the extraction time is 1h;

[0077] The content of polygonatum flavonoids in the polygonatum flavonoids extract was determined by sodium nitrite-aluminum nitrate colorimetry.

[0078] Example 3

[0079] (1) Wash and slice fresh rhizomes of Polygonatum cyrtonema into 1 mm thick slices, place in a drying oven at 60° C. and dry to constant weight, with a moisture content of 6-7%;

[0080] (2) Put the dried Polygonatum sibiricum slices into a grinder and grind them into 40 mesh and store them away from light;

[0081] (3) placing the polygonatum powder in a screw extruder for extrusion pretreatment to obtain a polygonatum expanded material. The screw extrusion parameters are as follows: screw speed 400 rpm, moisture content 30%, extrusion temperature 110°C, die hole diameter 10 mm;

[0082] (4) drying the expanded polygonatum sibiricum material in a drying oven at 60° C. to constant weight, and then crushing the expanded polygonatum sibiricum material in a grinder to 40 mesh;

[0083] (5) Extract flavonoids from the expanded material of polygonatum sibiricum by water bath method, filter twice, and cool to obtain the polygonatum sibiricum flavonoids extract. The extraction parameters are as follows: the organic solvent is 70% ethanol, the extraction temperature is 70°C, the material-liquid ratio is 1:15 (g / mL), and the extraction time is 1h;

[0084] The content of polygonatum flavonoids in the polygonatum flavonoids extract was determined by sodium nitrite-aluminum nitrate colorimetry.

[0085] Example 4

[0086] (1) Wash and slice fresh rhizomes of Polygonatum cyrtonema into 1 mm thick slices, place in a drying oven at 60° C. and dry to constant weight, with a moisture content of 6-7%;

[0087] (2) Put the dried Polygonatum sibiricum slices into a grinder and grind them into 40 mesh and store them away from light;

[0088] (3) placing the polygonatum powder in a screw extruder for extrusion expansion pretreatment to obtain a polygonatum expanded material. The screw extrusion expansion parameters are as follows: screw speed 350 rpm, moisture content 25%, extrusion temperature 100°C, die hole diameter 8 mm;

[0089] (4) drying the expanded Polygonatum sibiricum material in a drying oven at 60°C until constant weight;

[0090] (5) Put the expanded polygonatum sibiricum material into a grinder and grind it into 40 mesh;

[0091] (6) Extract flavonoids from the expanded material of polygonatum sibiricum by water bath method, filter twice, and cool to obtain the polygonatum sibiricum flavonoid extract. The extraction parameters are as follows: the organic solvent is 70% ethanol, the extraction temperature is 80°C, the material-liquid ratio is 1:15 (g / mL), and the extraction time is 1.5h;

[0092] The content of polygonatum flavonoids in the polygonatum flavonoids extract was determined by sodium nitrite-aluminum nitrate colorimetry.

[0093] Comparison example

[0094] The operation steps (1) to (2) are the same as those in Experiment 1.

[0095] (3) Extract flavonoids from polygonatum powder by water bath method, filter twice, and cool to obtain polygonatum flavonoid extract. The extraction parameters are as follows: organic solvent is 70% ethanol, extraction temperature is 80°C, solid-liquid ratio is 1:15 (g / mL), and extraction time is 1.5h;

[0096] The content of flavonoids in the flavonoids extract of sibiricum was determined by sodium nitrite-aluminum nitrate colorimetry. Figure 5 .

[0097] Under the same extraction parameters in the extraction stage, the main factor affecting the extraction effect in the pretreatment stage is the setting conditions of the screw extrusion. Under the conditions of screw speed 350rpm, moisture content 23-27%, outlet temperature 95-100℃, and die diameter 8mm, the cell wall is fully broken and loosened through the combined effects of extrusion, friction, shearing, high temperature and high pressure, and the flavonoid content in the extracted polygonatum flavonoid extract reaches 1.3%. When the extrusion parameters are fixed, in the extraction stage, the appropriate material-liquid ratio, higher temperature, and longer time can further increase the flavonoid content to more than 1.5%.

[0098] Although the present invention has been described above through embodiments, those skilled in the art should understand that without departing from the spirit and substance of the present invention, all improvements and modifications made to the present invention should fall within the protection scope of the present invention.

Claims

1. A method for extracting flavonoids from polygonatum, characterized in that: Including preprocessing and extraction operations: S1 pretreatment: slice the polygonatum, dry and crush it, and extrude it with a screw extruder; S2 extraction: extracting the expanded polygonatum material obtained in step S1 with an organic solvent, wherein the organic solvent is an ethanol aqueous solution with a mass fraction of 50-80%.

2. The method for extracting polygonatum flavonoids according to claim 1, characterized in that: The pre-processing comprises the steps of: S11: Slice the rhizome of Polygonatum cyrtonema and dry it at a temperature of 50-70° C. until the moisture content is less than 10%; S12: crushing the dried polygonatum slices into 40-100 meshes and storing them in a dark place; S13: placing the polygonatum powder in a screw extruder for extrusion and expansion to obtain a polygonatum expanded material; the screw extrusion and expansion parameters are as follows: screw speed 300-400rpm, moisture content 20-35%, extrusion temperature 90-115°C, die hole diameter 6-10mm.

3. The method for extracting polygonatum flavonoids according to claim 1, characterized in that: The extraction operation is: The expanded polygonatum material is subjected to flavonoid extraction by a water bath method, and then filtered and cooled to obtain a polygonatum flavonoid extract; the extraction parameters are as follows: the organic solvent is an ethanol aqueous solution with a mass fraction of 60-80%, the extraction temperature is 60-80°C, the material-liquid ratio is 1:15-25 (g / mL), and the extraction time is 0.5-2h.

4. The method for extracting polygonatum flavonoids according to claim 2, characterized in that: The polygonatum sibiricum is fresh polygonatum sibiricum, and / or In step S11, the slices of the rhizome of Polygonatum sibiricum are 1 to 2 mm thick and are dried in a drying oven at 50 to 70° C. until the moisture content is less than 10%.

5. The method for extracting polygonatum flavonoids according to claim 2, characterized in that: In step S13, water is added to the material to control the moisture content to 23-27%, and the extrusion temperature of the screw extruder is 95-100°C.

6. The method for extracting polygonatum flavonoids according to claim 2, characterized in that: In step S13, the screw extruder is a single screw extruder, and the screw extrusion and expansion parameters are: screw speed 300-350 rpm, and die hole diameter 8-10 mm.

7. The method for extracting polygonatum flavonoids according to any one of claims 1 to 6, characterized in that: In step S2, the organic solvent is an ethanol aqueous solution with a mass fraction of 65-75%, the extraction temperature is 78-82°C, and the extraction temperature is controlled by a water bath.

8. The method for extracting polygonatum flavonoids according to claim 3, characterized in that: In step S2, the material-liquid ratio is 1:15-16 (g / mL), and the extraction time is 1.3-1.5 hours; after extraction, the reaction mixture is filtered and cooled to obtain a polygonatum flavonoid extract.

9. The method for extracting polygonatum flavonoids according to claim 8, characterized in that: After extraction, the reaction mixture was filtered twice, the first filtration using gauze as the filter medium and the second filtration using filter paper.

10. Polygonatum sibiricum flavonoids obtained by the extraction method according to any one of claims 1 to 9.

Images