Method for extracting total flavonoids of traditional Chinese medicine cassia twig by using two aqueous phases

Abstract

The invention discloses a method for extracting traditional Chinese medicine cassia twig total flavonoids by using two aqueous phases, and belongs to the technical field of natural product extraction. The method comprises the following steps: (1) cleaning and drying cassia twigs, and then crushing the cassia twigs into powder to obtain cassia twig powder; (2) preparing an ammonium sulfate aqueous solution with the mass fraction of 16%-30%, then adding ethanol with the volume fraction of 17%-30%, mixing, and standing until the solution is subjected to phase splitting to form a two-aqueous-phase extracting agent; and (3) adding the cassia twig powder into the aqueous two-phase extracting agent according to a certain material-liquid mass ratio, mixing, heating at constant temperature, extracting for a certain time, centrifuging, and collecting upper-phase clear liquid to complete the extraction of the total flavonoids. The method has the advantages of being convenient and easy to implement, high in extraction amount, environmentally friendly and low in energy consumption, and provides help for research, development and utilization of cassia twigs.

Description

Technical Field

[0001] The invention relates to the technical field of natural product extraction, in particular to a method for extracting total flavonoids of cassia twig of a traditional Chinese medicine by utilizing aqueous two phases. Background Art

[0002] Cassia twig ( Cinnamomi ramulus ) is the dried young branches of the cinnamon bark of the Lauraceae family. It is pungent, sweet, and warm in nature. It has the effects of dispelling cold and relieving exterior symptoms, warming and unblocking the meridians, and promoting yang and transforming qi. In clinical practice, it is often used for colds, cold pain in the abdomen, amenorrhea due to cold blood, joint pain, phlegm, edema, palpitations, and other symptoms. Modern pharmacological studies have shown that cinnamon twigs have multiple physiological activities such as relieving gastrointestinal irritation, strengthening the heart, improving microcirculation, anti-inflammatory, and anti-platelet aggregation. Cinnamon twigs have important medicinal value and a wide range of pharmacological activities. They are used frequently in traditional Chinese medicine prescriptions and are used in multiple prescriptions. According to statistics, the frequency of use of cinnamon twigs in traditional Chinese medicine prescriptions is second only to licorice. In clinical practice, a series of classic prescriptions with cinnamon twigs as the main medicine have been formed, such as Guizhi Decoction, Mahuang Decoction, Guizhi Fuling Pills, etc., which are widely used in the treatment of various clinical diseases, such as coronary heart disease, arrhythmia, rheumatic heart disease and other cardiovascular diseases. This shows the important medicinal value of cinnamon twigs.

[0003] At present, the extraction methods of total flavonoids in cinnamon twig mainly include immersion method, ultrasonic method and reflux method. Among them, the extraction efficiency of immersion method is relatively low. This is mainly due to the relatively slow mass transfer rate between the solvent and the medicinal material during the immersion process, the limited dissolution rate of flavonoid compounds, and the long-term immersion may also lead to the dissolution of a large number of impurities, thereby further reducing the purity and extraction rate of the target flavonoids. The equipment cost of the ultrasonic method is relatively high, and when it is applied on a large scale, the uniformity of the ultrasonic wave is difficult to ensure, which is easy to cause excessive local energy to destroy the structure of some flavonoid components, affecting their activity and extraction yield, and there is also a noise pollution problem. The reflux method has a large energy consumption, and may cause the degradation of heat-sensitive flavonoid components during the heating process. It also requires a more complex condensation device, and there are certain hidden dangers in terms of operational safety.

[0004] In the process of extracting total flavonoids from other natural raw materials, there is a method of operating with a two-phase aqueous system. For example, a method of separating total flavonoids from kudzu root by microwave-assisted two-phase aqueous extraction is disclosed in the Chinese invention patent with publication number CN103432193A. At its operating temperature, the two phases are also clearly separated, and the kudzu root powder is just suspended between the two phases. The flavonoids that are easily soluble in the ethanol phase are extracted and enter the upper phase, and the polysaccharides that are easily soluble in the water phase are dissolved in the lower phase. Thus, the extraction and separation processes are carried out simultaneously. Pueraria root flavonoids are significantly enriched in the upper phase, and there is almost nothing in the lower phase. By changing the mass fraction of the added salt to change the volume of the upper and lower phases, the volume of the upper phase is reduced to achieve the purpose of enrichment and concentration. Pueraria root flavonoids are easily soluble in weakly alkaline solutions due to their structural characteristics. The two-phase aqueous extractant formed by potassium dihydrogen phosphate and ethanol is weakly alkaline, and the pH range is 7-11, which is conducive to the dissolution of kudzu root flavonoids. However, the biological differences between plants (such as cell structure and metabolite composition) and the chemical properties of flavonoids jointly determine the extraction efficiency of the two-phase aqueous system. Flavonoids are mostly present in the form of aglycones or glycosides in plants, and the substitution position and number of sugar groups will affect their polarity and solubility. In addition, the thickness and composition of the cell walls of different plants vary significantly, and polysaccharides, proteins, tannins, etc. can compete with flavonoids for distribution to a certain phase. Therefore, in actual operation, it is difficult to simply determine the methods and parameters for the extraction of total flavonoids from different plant raw materials through process replacement or limited experiments. Targeted design of the composition, structure and other characteristics of the selected raw materials is required to obtain the best extraction effect.

[0005] The chemical components of cinnamon twig are partly phenylpropanoid / phenolic acid compounds, and partly glycoside compounds. The flavonoid compounds of cinnamon twig include kaempferol-7-rhamnoside, lyoniresinol, 5.7.3'-trimethoxyl-(-)-epicatechin and 5,7-dimethoxyl-3',4'-di-O-methy-lene-epicatechin, among which kaempferol-7-rhamnoside is less stable. It is difficult to extract at high temperature, and avoid extraction in strong acid and strong base environment, because acid and base conditions may hydrolyze glycosidic bonds and affect the stability of the compound. Lyoniresinol, 5.7.3'-trimethoxyl-(-)-epicatechin and 5,7-dimethoxyl-3', 4'-di-O-methy-lene-epicatechin, these two compounds may be more closely combined with other components in plant tissues due to their complex structure and large steric hindrance, and the extraction may be more difficult. The raw material characteristics of cinnamon twigs put forward higher requirements for process design. Increasing the extraction amount of total flavonoids from cinnamon twigs based on the two-aqueous phase system is of great significance in the fields of biomedicine and so on. Summary of the invention

[0006] In view of the above-mentioned defects of the prior art, the present invention provides a method for extracting total flavonoids from cinnamon twig of traditional Chinese medicine with convenient and easy steps and high extraction yield, comprising the following steps: (1) washing and drying cinnamon twigs, and then crushing them into powder to obtain cinnamon twig powder; (2) preparing an aqueous solution of ammonium sulfate with a mass fraction of 16% to 30%, then adding ethanol with a volume fraction of 17% to 30% and mixing, and standing until the solution separates into phases to form a two-phase aqueous extractant; (3) Add cinnamon twig powder to the aqueous two-phase extractant according to a certain material-liquid mass ratio, mix and heat at a constant temperature for extraction for a certain period of time, then centrifuge and collect the upper clear liquid to complete the extraction of total flavonoids.

[0007] Preferably, the specific process of step (1) is as follows: wash the cinnamon twigs with ultrapure water, vacuum dry to constant weight, and then grind into powder, sieve to obtain cinnamon twig powder, and place in a cool and dry place for later use.

[0008] More preferably, the vacuum drying temperature is 50-70°C.

[0009] Timely drying after washing can reduce the moisture content, inhibit the activity of endogenous enzymes in cinnamon twigs, and prevent the degradation of flavonoids in enzymatic reactions; at the same time, it can reduce water activity, avoid the growth of microorganisms, and ensure the cleanliness and stability of the raw materials. Flavonoids are sensitive to high temperatures. Choosing a mild drying temperature can effectively remove moisture and avoid oxidative decomposition or structural damage of flavonoids caused by high temperatures, thereby retaining their biological activity to the greatest extent.

[0010] Further preferably, the mesh size of the sieve is 60 meshes.

[0011] The aqueous two-phase extractant of the present invention has a good extraction effect on the total flavonoids of cinnamon twigs, and correspondingly reduces the difficulty of pretreatment of cinnamon twig raw materials. Compared with processes such as ultrasonic vibration or enzyme treatment, ordinary crushing methods can be used, which is lower in cost and has a wide range of applications. After crushing, passing through a 60-mesh sieve (aperture of about 0.25 mm) can make the cinnamon twig particles smaller and more uniform, significantly increasing the contact area with the aqueous two-phase extractant. The fine particle size of the 60-mesh sieve helps to destroy the plant cell wall structure during the mechanical crushing process and reduce the dissolution resistance of flavonoid components.

[0012] Preferably, in step (2), the mass fraction of the ammonium sulfate aqueous solution is 24%, and the volume fraction of ethanol is 20%.

[0013] Preferably, in step (3), the mass ratio of the aqueous two-phase extractant to the cassia twig powder is 10-40:1 mL / g.

[0014] Further preferably, the mass ratio of the cinnamon twig powder to the aqueous two-phase extractant is 16:1 mL / g.

[0015] Preferably, in step (3), the temperature of the constant temperature heating is 60°C.

[0016] The low temperature range of 40-50 ℃ can effectively protect heat-sensitive components (such as kaempferol-7-rhamnoside, etc.), while ensuring the normal phase separation of the two-phase aqueous system, it can minimize thermal degradation and is suitable for the extraction of heat-sensitive flavonoids; although the high temperature of 70-80 ℃ can shorten the extraction time by accelerating molecular motion, it may affect the stability of some heat-sensitive components. 60 ℃ is the optimal extraction temperature. Under this condition, the mass transfer efficiency of the two-phase aqueous system is high, which can not only promote the dissolution of flavonoids and their distribution to the upper ethanol phase, but also inhibit the activity of endogenous enzymes and prevent enzymatic degradation. Therefore, the present invention selects 60 ℃ as the extraction condition.

[0017] Preferably, in step (3), the extraction time is 20-60 min.

[0018] Further preferably, the extraction time is 50 min.

[0019] Based on the above technical solutions, the design concept and principle of the present invention are as follows: The chemical components of cinnamon twig are partly phenylpropanoids / phenolic acid compounds, which are soluble in ethanol and have a certain water solubility; partly glycoside compounds are insoluble in ethanol and have a certain water solubility. Therefore, in the aqueous two-phase extractant of the present invention, the phenylpropanoids or phenolic acid compounds in cinnamon twig are partially dissolved in the aqueous phase, and the glycoside compounds in cinnamon twig are completely dissolved in the aqueous phase in the aqueous two-phase. Extracting cinnamon twig with an aqueous two-phase extractant can separate these substances, while the current cinnamon twig extraction technology (such as ultrasonic extraction, ethanol reflux method, leaching method) cannot achieve this separation effect.

[0020] The inventors considered that the organic acid components contained in cinnamon twigs exist in dissociation equilibrium in neutral or alkaline solvents. The increase of alkaline substances turns the molecular organic acids into ionic salt substances. According to the principle of like dissolves like, these substances are not easily soluble in the organic phase with low polarity, but are easily left in the aqueous phase. The lower phase of the ammonium sulfate-ethanol two-phase aqueous system is weakly alkaline, and the organic acids are turned into ionic salt substances and remain in the lower phase, reducing the impurities in the upper phase (ethanol phase). In addition, the interference of organic acid compounds is avoided when determining flavonoids, which helps to reduce the difficulty of quality control under industrial production conditions.

[0021] The two-phase aqueous extractant of the present invention has mild use conditions and will not cause inactivation or denaturation of the extracted components due to problems with the reaction conditions; it has strong selectivity for specific target components in cassia twigs, and most impurities can be removed together with solid matter, simplifying the separation process; natural phase separation can be completed in a short time, greatly shortening the reaction time; and the recovery rate of the target product is several times higher than that of the traditional method.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects: The invention provides a method for extracting total flavonoids from cinnamon twig, a traditional Chinese medicine. It utilizes an ethanol-ammonium sulfate aqueous two-phase system to extract flavonoids from cinnamon twig for the first time. The method has the advantages of being convenient and easy to operate, having a high extraction yield, being green and environmentally friendly, and having low energy consumption, and provides help for the research, development, and utilization of cinnamon twig. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the effect of the mass fraction of ammonium sulfate on the yield of total flavonoids in cinnamon twig; Figure 2 This is a schematic diagram of the effect of ethanol volume fraction on the yield of total flavonoids in cinnamon twig; Figure 3 This is a schematic diagram of the effect of liquid-to-solid ratio on the yield of total flavonoids from cinnamon twig; Figure 4 It is a schematic diagram of the effect of extraction time on the yield of cinnamon flavonoids; Figure 5 The response surface and contour map of the effect of ammonium sulfate mass fraction and ethanol volume fraction on the yield of total flavonoids in cinnamon twig; Figure 6 The response surface and contour map of the effect of ammonium sulfate mass fraction and material-liquid ratio on the yield of total flavonoids in cinnamon twig; Figure 7 The response surface and contour map of the effects of ammonium sulfate mass fraction and extraction time on the yield of total flavonoids in cinnamon twig; Figure 8 It is the response surface and contour map of the effect of liquid-to-solid ratio and ethanol volume fraction on the yield of total flavonoids in cassia twig; Fig. 9 The response surface and contour map of the effects of extraction time and ethanol volume fraction on the total yield of flavonoids from cassia twig; Fig.10 Response surface and contour plot of the effects of extraction time and liquid-to-solid ratio on the yield of total flavonoids from cinnamon twig. DETAILED DESCRIPTION

[0024] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0025] In the following embodiments: Cinnamon twig detection uses KAc-Al(NO3)3 colorimetric system. When KAc-Al(NO3)3 system is added to a solution containing flavonoid compounds, Al in Al(NO3)3 3+Ions will react with the phenolic hydroxyl groups in the flavonoid molecules to form a stable flavonoid Al³⁺ complex. The maximum absorption wavelength is at 418 nm; take 1 mL of the ethanol phase after extraction, dilute to 50 mL, and take 10 mL from it and add it to a 25 mL volumetric flask, add 0.1 mol / L Al(NO3)32mL, 1mol / L KAc 3mL, add water to make up to, measure the absorbance at 418 nm, and substitute it into the standard curve to calculate the concentration, and use the following formula to get the total flavonoid yield of cassia twig: M = (a × c × V) / m; In the formula: c-flavonoid concentration of the upper phase extract, mg / mL; V-volume of the upper phase extract, mL; a-dilution multiple; m-weight of the weighed cinnamon twig powder, mg; M-yield of total flavonoids from cinnamon twig, mg / g.

[0026] The method for drawing the standard curve is as follows: using rutin as the standard, using the KAc-Al(NO3)3 colorimetric method, and selecting 418nm as the detection wavelength, the total flavonoids in cinnamon twigs were determined. Weigh 5 mg of rutin in a 25 mL volumetric flask, add anhydrous ethanol to the scale, shake well, and obtain a rutin standard solution with a mass concentration of 0.2 mg / mL. Take 6 marked 10 mL volumetric flasks, add 0 mL, 0.8 mL, 1.2 mL, 1.5 mL, 2 mL, and 2.5 mL of rutin standard solution, add water to 5 mL, add 0.1 mol / L Al(NO3)32mL, and 1mol / L KAc 3mL. Take the first solution as the reference and measure the absorbance at 418 nm. Draw a standard curve with concentration as the horizontal axis and absorbance as the vertical axis.

[0027] Example 1 This embodiment provides a method for extracting total flavonoids from cinnamon twig, the steps are as follows: (1) Wash cinnamon twigs with ultrapure water for three times, place in a vacuum drying oven, set the temperature to 60 °C and dry to constant weight, then grind into powder, pass through a 60-mesh sieve to obtain cinnamon twig powder, put into a reserve bag and place in a cool and dry place for later use; (2) taking an aqueous solution of ammonium sulfate (mass fractions of 16%, 19%, 21%, 24%, 25.5%, 26%, 27%, and 30%, respectively), and then adding anhydrous ethanol (volume fractions of 17%, 20%, 23%, 26%, and 30%, respectively), and letting it stand to obtain an upper phase liquid and a lower phase liquid, thereby forming a two-phase aqueous extractant; (3) Cinnamon twig powder was added to the aqueous two-phase extractant according to the liquid-to-solid ratio (10:1 mL / g, 15:1 mL / g, 19:1 mL / g, 20:1 mL / g, 25:1 mL / g, 30:1 mL / g, 35:1 mL / g, and 40:1 mL / g, respectively). After sufficient shaking, the extract was placed in a constant temperature water bath for extraction for a certain period of time (the extraction time was 20 min, 30 min, 40 min, 50 min, and 60 min, respectively). The extract was then transferred to a 50 mL centrifuge tube and centrifuged at 2500 r / min for 15 min. The supernatant was collected to complete the extraction of total flavonoids.

[0028] Example 2 This example is based on the method of Example 1, based on a single factor experiment, to investigate the effects of four factors, namely, the mass fraction of ammonium sulfate, the volume fraction of ethanol, the liquid-to-solid ratio, and the extraction time, on the yield of total flavonoids in cinnamon twig, so as to study the application effect of this method.

[0029] The liquid-to-solid ratio was fixed at 20:1 (mL / g), the ethanol volume fraction was 30%, the extraction temperature was 60 ℃, and the extraction time was 20 min for the two-phase aqueous extraction of total flavonoids from cinnamon twig. When the mass fraction of ammonium sulfate was lower than 16% or higher than 30%, the two-phase aqueous system did not separate into phases, so the mass fraction of ammonium sulfate was set to (16%-30%) for extraction, and the total flavonoid yield was detected. The results are shown in Table 1. The trend of the total flavonoid yield of cinnamon twig is as follows Figure 1 shown.

[0030] Table 1: Yield of total flavonoids of cinnamon twig at different ammonium sulfate mass fractions

[0031] It can be seen from the data in Table 1 that when the mass fraction of ammonium sulfate is 16%-30%, the total flavonoids yield first increases and then decreases. When the mass fraction of ammonium sulfate is 25.5%, the total flavonoids yield reaches the maximum. Therefore, the mass fraction of ammonium sulfate of 25.5% is selected as the extraction condition.

[0032] The mass fraction of ammonium sulfate was fixed at 25.5%, the solid-liquid ratio was 20:1 (mL / g), the extraction temperature was 60 °C, and the extraction time was 20 min. Under this condition, if the volume fraction of ethanol was lower than 17% or greater than 30%, the two-phase aqueous system would not separate into phases. Therefore, the volume fraction of ethanol was set to (17%-30%) for two-phase aqueous extraction of total flavonoids from cinnamon twigs, and the yield of total flavonoids was detected. The experimental results are shown in Table 2. The trend of the yield of total flavonoids from cinnamon twigs is shown in Table 2. Figure 2 shown.

[0033] Table 2: Total flavonoids yield of cinnamon twig at different ethanol volume fractions

[0034] From the data in Table 2, it can be seen that when the volume fraction of ethanol is 16%-30%, the flavonoid yield first increases and then decreases. When the volume fraction of ethanol is 23%, the flavonoid yield reaches the maximum. Therefore, the volume fraction of ethanol is 23% as the extraction condition.

[0035] The mass fraction of ammonium sulfate was fixed at 25.5%, the volume fraction of ethanol was 23%, the extraction temperature was 60 °C, and the extraction time was 20 min. The liquid-to-solid ratio was changed to detect the flavonoid yield. The experimental results are shown in Table 3. The trend of the total flavonoid yield of cinnamon twig is as follows: Figure 3 shown.

[0036] Table 3: Total flavonoids yield of cinnamon twig under different material-liquid ratios

[0037] It can be seen from the data in Table 3 that when the solid-liquid ratio is 10-40:1 mL / g, the total flavonoids yield first increases and then decreases. When the liquid-to-solid ratio is 19:1, the total flavonoids yield reaches the maximum. Therefore, the liquid-to-solid ratio of 19:1 mL / g is selected as the extraction condition.

[0038] The mass fraction of ammonium sulfate was fixed at 25.5%, the volume fraction of ethanol was 23%, the liquid-to-solid ratio was 19:1 mL / g, the extraction temperature was 60 °C, and the extraction time was set at 20 min, 30 min, 40 min, 50 min, and 60 min, respectively, for the two-phase extraction of total flavonoids from cinnamon twig, and the yield of total flavonoids was detected. The experimental results are shown in Table 4. The trend of the yield of total flavonoids from cinnamon twig is shown in Figure 4 shown.

[0039] Table 4: Total flavonoids yield of cinnamon twig at different extraction times

[0040] From the data in Table 4, it can be seen that the yield of total flavonoids first increases and then decreases with the increase of extraction time. The yield is the highest when the extraction time is 40 min, that is, the extraction time is favorable when the extraction time is 40 min.

[0041] Example 3 Based on the results of the single factor experiment, this example further optimized the experimental conditions of the aqueous two-phase extraction of flavonoids using the response surface methodology to determine the optimal extraction parameters and effects of this method.

[0042] The response surface experiment was designed as follows: Based on the results of the single factor experiment, the experimental conditions of the two-phase aqueous extraction of flavonoids were optimized in one step by the response surface methodology. The four factors of ammonium sulfate mass fraction, ethanol volume fraction, extraction time, and liquid-to-solid ratio were selected as independent variables, and the total flavonoid yield was used as the response value. The Box-Bchnken central composite design scheme was used, and the experimental data were subjected to regression analysis using Design-Expert 13.0 software. The experimental factor levels are shown in Table 5.

[0043] Table 5: Response surface analysis experimental factor levels

[0044] According to the Box-Benhnken design principle, a total of 29 response surface analysis experiments with 4 factors and 3 levels were conducted. The specific results are shown in Table 6. The response surface and contour diagram of the effects of different factor combinations on the yield of total flavonoids from cassia twig are shown in Table Figure 5-10 shown.

[0045] Table 6: Response surface experimental design and results

[0046] Model establishment and significance analysis: Design-Expert 13.0 software was used to analyze the response surface experimental data and perform multivariate regression fitting. A quadratic regression equation with total flavonoid yield as a function was established, and variance analysis and significance test were performed on the regression equation. The results are shown in Table 7.

[0047] The quadratic regression equation of total flavonoid yield (Y) with ammonium sulfate mass fraction (A), ethanol volume fraction (B), liquid-to-solid ratio (C) and extraction time (D) is: Y=39.6-3.40A-5.57B+5.32C+6.02D+0.8215AB-4.65AC+4.76AD-8.94BC+4.51BD+6.19CD-6.21A 2 -4.73B 2 -11.76C 2 -1.77D 2 .

[0048] Table 7: Analysis of variance for regression models

[0049] As shown in Table 7, the regression model used in this experiment has excellent significance (P < 0.01), the model determination coefficient = 0.9602, the degree of fit is high, and the correction coefficient = 0.9203, indicating that the model equation can explain 92.03% of the response value changes. The lack of fit term P = 0.7971 > 0.05, indicating that the lack of fit term of the model is not significant, and the overall absolute error of the model is small, indicating that the functional relationship between the yield and each factor selected by response surface analysis simulation has certain scientific rationality. According to the F value, the influence of each factor on the yield of total flavonoids in cassia twig is D > B > C > A from large to small, that is, extraction time > ethanol volume fraction > liquid-to-solid ratio > ammonium sulfate mass fraction. In addition, A, B, C, D, AD, BC, BD, CD, have extremely significant effects on the yield of total flavonoids (P < 0.01).

[0050] The optimal extraction conditions predicted by the response surface test are: ammonium sulfate mass fraction of 24.079%, ethanol volume fraction of 20.046%; liquid-to-solid ratio of 15.38:1 mL / g, extraction time of 50 min. Considering the need for practical operation, the ammonium sulfate mass fraction is preferably 24%, the ethanol volume fraction is preferably 20%; the liquid-to-solid ratio is preferably 16:1 mL / g, and the extraction time is preferably 50 min. Under these conditions, the theoretical value of the total flavonoid yield can reach 47.054 mg / g. The KAc-Al(NO3)3 color development system was used to repeat the test three times, and it was detected that under the above parameters, the actual extraction of total flavonoids of cinnamon twig was 47.03 mg / g, 47.06 mg / g, and 47.05 mg / g, respectively, with an average value of 47.04 mg / g, which is very close to the theoretical value. The experimental results are consistent with the model. The method of the present invention has a significant effect on the extraction of total flavonoids of cinnamon twig.

[0051] In summary, the two-phase aqueous extractant of the present invention has mild use conditions and will not cause inactivation or denaturation of the extracted components due to problems with the reaction conditions; it has strong selectivity for specific target components in cinnamon twigs, and most impurities can be removed together with the solid matter, simplifying the separation process; natural phase separation can be completed in a short time, greatly shortening the reaction time; and the recovery rate of the target product is several times higher than that of the traditional method, which provides help for the research, development and utilization of cinnamon twigs.

[0052] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for extracting total flavonoids from cinnamon twig, characterized in that: The steps include: (1) washing and drying cinnamon twigs, and then crushing them into powder to obtain cinnamon twig powder; (2) preparing an aqueous solution of ammonium sulfate with a mass fraction of 16% to 30%, then adding ethanol with a volume fraction of 17% to 30% and mixing, and standing until the solution separates into phases to form a two-phase aqueous extractant; (3) Add cinnamon twig powder to the aqueous two-phase extractant according to a certain material-liquid mass ratio, mix and heat at a constant temperature for extraction for a certain period of time, then centrifuge and collect the upper clear liquid to complete the extraction of total flavonoids.

2. The method for extracting total flavonoids from cinnamon twig according to claim 1, characterized in that: The specific process of step (1) is as follows: wash the cinnamon twigs with ultrapure water, vacuum dry to constant weight, and then grind into powder, sieve to obtain cinnamon twig powder, and place in a cool and dry place for later use.

3. The method for extracting total flavonoids from cinnamon twig according to claim 2, characterized in that The vacuum drying temperature is 50-70°C.

4. The method for extracting total flavonoids from cinnamon twig according to claim 2, characterized in that The mesh number of the sieve is 60 meshes.

5. The method for extracting total flavonoids from cinnamon twig of Chinese medicine according to claim 1, characterized in that: In the step (2), the mass fraction of the ammonium sulfate aqueous solution is 24%, and the volume fraction of ethanol is 20%.

6. The method for extracting total flavonoids from cinnamon twig according to claim 1, characterized in that: In the step (3), the mass ratio of the aqueous two-phase extractant to the cassia twig powder is 10-40:1 mL / g.

7. The method for extracting total flavonoids from cinnamon twig according to claim 6, characterized in that: The mass ratio of the cinnamon twig powder to the aqueous two-phase extractant is 16:1 mL / g.

8. The method for extracting total flavonoids from cinnamon twig according to claim 1, characterized in that: In the step (3), the constant temperature heating temperature is 60°C.

9. The method for extracting total flavonoids from cinnamon twig according to claim 1, characterized in that: In the step (3), the extraction time is 20-60 min.

10. The method for extracting total flavonoids from cinnamon twig according to claim 9, characterized in that: In the step (3), the extraction time is 50 min.

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