A method for preparing scutellaria baicalensis extract by circulating acid precipitation

Abstract

The present invention relates to a cyclic acid precipitation preparation method for a scutellaria baicalensis extract. The method comprises the following steps: extracting the scutellaria baicalensis, concentrating under reduced pressure to obtain a concentrated solution, dividing the concentrated solution into four to six portions and sequentially acid precipitating the solution, and using the supernatant produced each time for the next acid precipitation. The acid precipitation has a pH value between 1 and 3, and the solution is kept at 75°C and 85°C for 0.5 to 1.5 hours, then allowed to stand at room temperature for 1 to 3 hours. The last supernatant is allowed to stand alone for 1 to 3 days, filtered, and dried to obtain an extract. The process of the present invention greatly shortens the acid precipitation time, reduces the amount of wastewater discharged (specific data are shown in the main text), is simple and feasible to operate, and has low cost.

Description

Technical Field

[0001] The invention belongs to the field of plant extracts, and particularly relates to a cyclic acid precipitation preparation method for a scutellaria baicalensis extract. Background Art

[0002] Scutellaria baicalensis is a traditional Chinese medicinal herb with a bitter and cold nature. It has the effects of clearing heat and dampness, purging fire and detoxifying, stopping bleeding, and stabilizing pregnancy. Modern pharmacology shows that Scutellaria baicalensis has broad-spectrum antimicrobial effects and is not prone to drug resistance.

[0003] Baicalin is a major active ingredient in Scutellaria baicalensis and an important component in its antibacterial effects. At the same time, baicalin also has anti-inflammatory, anti-tumor, anti-organ fibrosis, cardiovascular and cerebrovascular protection, immune enhancement, and neuroprotective effects. Studies have also shown that purified high-purity baicalin extracts are not optimal for their anti-inflammatory and antipyretic effects. If the purity of baicalin is appropriately reduced and other components such as baicalein, wogonin, and scutellarin are retained, they can work together with baicalin to enhance the overall efficacy of the extract. This also confirms the synergistic effect between the various components of Chinese herbal medicine extracts.

[0004] Existing methods for preparing Scutellaria baicalensis extracts all focus on obtaining baicalin of higher purity. Acid precipitation, alkali dissolution, and re-acid precipitation are used to obtain an extract with a baicalin content of over 85%. This extract is then further refined using activated carbon, column chromatography, or enzymatic methods to obtain a high-purity baicalin extract with a content of over 90%. However, if the extract itself is used as a product with medicinal properties, the efficacy of the high-purity baicalin is slightly inferior to that of the low-purity baicalin extract. Studies have shown that in the preparation of Scutellaria baicalensis extracts, the product obtained by acid precipitation alone in the first step is most effective in increasing the content of the active ingredients. Furthermore, this product exhibits better anti-inflammatory and antipyretic effects than subsequent refined products.

[0005] In traditional methods for producing Scutellaria baicalensis extract, the first acid precipitation step typically requires 12 hours of standing at room temperature to completely precipitate the baicalin in the supernatant, thereby minimizing losses. However, this step is time-consuming and produces a large amount of wastewater. Therefore, a cyclic acid precipitation process for producing low-content Scutellaria baicalensis extract that reduces wastewater discharge, significantly shortens the time required, and still ensures a high yield of baicalin is urgently needed. Summary of the Invention

[0006] The invention provides a cyclic acid precipitation preparation method for a scutellaria baicalensis extract, which greatly reduces time cost and wastewater treatment cost under the premise of ensuring a baicalin yield of more than 90% (the mass of baicalin in the extract is the percentage of the mass of baicalin in the extract).

[0007] In one aspect, the present invention provides a method for preparing a scutellaria baicalensis extract by cyclic acid precipitation, comprising the following steps:

[0008] (1) Take the medicinal material of Scutellaria baicalensis and extract it twice with water to obtain the extract.

[0009] (2) The extract was divided into five parts and concentrated under vacuum to obtain concentrated solution 1, concentrated solution 2, concentrated solution 3, concentrated solution 4 and concentrated solution 5.

[0010] (3) The pH of the concentrated solution 1 was adjusted with hydrochloric acid, kept warm for a period of time, allowed to stand at room temperature, filtered, and dried to obtain the extract 1.

[0011] (4) Add the concentrated solution 2 to the supernatant of step (3), adjust the pH with hydrochloric acid, keep warm for a period of time, let it stand at room temperature, filter, and dry to obtain extract 2.

[0012] (5) Add the concentrated solution 3 to the supernatant of step (4), adjust the pH with hydrochloric acid, keep warm for a period of time, let it stand at room temperature, filter, and dry to obtain extract 3.

[0013] (6) The concentrated solution 4 is added to the supernatant of step (5), the pH is adjusted with hydrochloric acid, the mixture is kept warm for a period of time, allowed to stand at room temperature, filtered, and dried to obtain the extract 4.

[0014] (7) The concentrated solution 5 is added to the supernatant of step (6), the pH is adjusted with hydrochloric acid, the mixture is kept warm for a period of time, allowed to stand at room temperature, filtered, and dried to obtain the extract 5.

[0015] (8) The supernatant of step (7) was allowed to stand at room temperature, filtered, and dried to obtain extract 6.

[0016] (9) Extracts 1-6 are mixed or stored separately to obtain the Scutellaria baicalensis extract.

[0017] The extraction conditions of step (1) are as follows: the ratio of medicinal material to water is 1:8-1:15 (g / mL), the number of extractions is 1-3 times, the extraction temperature is 90° C.-100° C., and the extraction time is 1-3 hours.

[0018] The vacuum concentration conditions in step (2) are as follows: vacuum degree 0.07MPa-0.09MPa and temperature between 65°C and 75°C.

[0019] The concentrated solution 1 in step (2) is a concentrated solution concentrated to 1 / 3 to 1 / 2 of the volume of the original extract, and the concentrated solutions 2-5 are concentrated to 1 / 5 to 1 / 4 of the volume of the original extract.

[0020] In steps (3) to (7), the pH value adjusted by hydrochloric acid is 1-3, the insulation temperature is 75° C.-85° C., the insulation time is 0.5-1.5 hours, and the standing time at room temperature is 1-3 hours.

[0021] The standing time in step (8) is 1-3 days.

[0022] In another aspect, the present invention provides a Scutellaria baicalensis extract.

[0023] The scutellaria baicalensis extract is obtained by the aforementioned preparation method, and any scutellaria baicalensis medicinal material can be used as a raw material.

[0024] Advantages of the present invention: 1. The acid precipitation in the present invention is allowed to stand for 1-3 hours each time, and the supernatant obtained from the previous acid precipitation is used for the next acid precipitation. Compared with the traditional acid precipitation which requires standing for 12 hours per time, the loss of baicalin in the supernatant is effectively reduced while saving 5 / 6 of the time cost.

[0025] Advantage 2 of the present invention: The present invention recycles the supernatant used in acid precipitation four to six times, reducing wastewater discharge and wastewater treatment costs to 1 / 5 of those of traditional methods, and reducing hydrochloric acid usage to 1 / 3 of those of traditional methods. This reduces pollution and is beneficial to environmental protection.

[0026] Advantages of the present invention 3. The present invention can be widely used in various fields of humans, animals and plants, including human medicines and raw materials, health products, food and cosmetics, animal feed raw materials and veterinary drugs, plant biological pesticides, etc. DETAILED DESCRIPTION

[0027] The present invention is described in detail below by giving examples. The protection scope of the present invention is not limited to the following specific examples.

[0028] Example 1 Effect of concentration ratio and acid precipitation pH on the extract

[0029] To a 10L round-bottom flask, add 1000mL of water. Heat in a water bath until boiling. Add 100g of Scutellaria baicalensis and extract at 100°C for 2h. Filter, retain the filtrate in the round-bottom flask, add 1000mL of water, extract at 100°C for 1h, and filter. Combine the filtrates to obtain the extract. Concentrate the extract under reduced pressure at 60°C to half the volume of the original extract. Take half of this and divide it equally into two portions to obtain Concentrate 1 and Concentrate 2. Continue concentrating the remaining portion to a total volume of 1 / 4 of the original extract. Take half of this to obtain Concentrate 3, and concentrate the remaining half to half the volume to obtain Concentrate 4. Adjust Concentrate 1 to a pH of 1 with hydrochloric acid, Concentrate 2 to a pH of 2 with hydrochloric acid, and Concentrate 3 to a pH of 1 with hydrochloric acid. All three concentrates are incubated at 80°C for 2h, allowed to stand at room temperature for 14h, and then centrifuged to obtain the precipitate. Assay the content and calculate the yield. The results are shown in Tables 1 and 2.

[0030] Table 1 Effect of concentration multiples on baicalin content

[0031]

[0032] As shown in Table 1, concentration to 1 / 4 of the original volume had no significant effect on the baicalin content in the concentrate, but an effect was observed at 1 / 8 of the original volume. Therefore, it is considered that concentrations above 1 / 4 are acceptable. Furthermore, since concentration to 1 / 8 of the original volume was too small and was known to affect the content, the acid precipitation experiment was not performed.

[0033] Table 2 Effect of acid precipitation pH on baicalin content

[0034]

[0035] As shown in Table 2, the acid precipitation effect at pH 1 is better than that at pH 2. From the perspective of the quality of baicalin in the supernatant, more baicalin can be precipitated when the pH is 1; from the perspective of the yield of the extract, the yield at pH 1 is higher than that at pH 2.

[0036] Example 2 Effects of acid precipitation holding time and holding temperature on the extract

[0037] To a 10L round-bottom flask, add 1000mL of water and heat in a water bath until boiling. Add 100g of Scutellaria baicalensis and extract at 100°C for 2 hours. Filter, retain the residue in the round-bottom flask, add 1000mL of water, extract at 100°C for 1 hour, and filter. Combine the filtrates to obtain an extract. Concentrate the extract under reduced pressure at 60°C to half the volume of the original extract, obtaining concentrated solution 1. The concentrated solution was divided into three equal portions, adjusted to pH 1 with hydrochloric acid, and numbered 1-3. Portion 1 was incubated at 80°C for 0.5 hours and allowed to stand at room temperature for 14 hours; portion 2 was incubated at 80°C for 1 hour and allowed to stand at room temperature for 14 hours; and portion 3 was incubated at 70°C for 2 hours and allowed to stand at room temperature for 14 hours. The precipitate was centrifuged, assayed, and the yield calculated. The results are shown in Tables 3 and 4.

[0038] Table 3 Effect of acid precipitation temperature on baicalin content

[0039]

[0040] The results show that the insulation effect of 80℃ is the best.

[0041] Table 4 Effect of acid precipitation holding time on baicalin content

[0042]

[0043] As can be seen from Table 4, the effects of holding at 80°C for half an hour and for two hours are similar. Considering the cost, holding for half an hour is chosen.

[0044] Example 3 Effect of standing time on extract

[0045] 500 mL of the remaining concentrated solution was taken and adjusted to pH 1 with hydrochloric acid. The solution was kept at 80°C for 0.5 h and allowed to stand at room temperature. Samples were taken at regular intervals to determine the baicalin content in the supernatant. The precipitation of baicalin with standing time was calculated. The results are shown in Table 5.

[0046] Table 5 Effect of standing time on baicalin content

[0047]

[0048] The results show that a significant downward trend appears after 2 h of rest, and a second downward trend appears after 14 h of rest. Therefore, 2 h and 14 h were selected as the two resting stages.

[0049] Example 4 Circulating Acid Sedimentation of Scutellaria Baicalensis Extract

[0050] To a 10L round-bottom flask, add 4000mL of water and heat to boiling at 100°C. Add 400g of Scutellaria baicalensis and extract at 100°C for 2 hours. Filter and retain the residue. Add 4000mL of water and extract at 100°C for 1 hour. Filter. Combine the two filtrates to obtain 8000mL of extract. Take 5000mL of the extract and concentrate under reduced pressure to 2500mL. Take 500mL of this extract and label it as Concentrate 1. Continue concentrating the remaining portion to 1000mL and divide it into four equal portions of 250mL each, labeled Concentrates 2-5. Adjust the pH of 500mL of Concentrate 1 to 1 with hydrochloric acid, incubate at 80°C for 0.5 hours, and let it stand at room temperature for 2 hours. Filter and dry to obtain Extract 1. Reserve the supernatant. Add 250 mL of concentrated solution 2 to the supernatant, adjust the pH to 1 with hydrochloric acid, incubate at 80°C for 0.5 hour, let stand at room temperature for 2 hours, filter, and dry to obtain Extract 2. The supernatant is retained. Add 250 mL of concentrated solution 3 to the supernatant, adjust the pH to 1 with hydrochloric acid, incubate at 80°C for 0.5 hour, let stand at room temperature for 2 hours, filter, and dry to obtain Extract 3. The supernatant is retained. Add 250 mL of concentrated solution 4 to the supernatant, adjust the pH to 1 with hydrochloric acid, incubate at 80°C for 0.5 hour, let stand at room temperature for 2 hours, filter, and dry to obtain Extract 4. The supernatant is retained. Add 250 mL of concentrated solution 5 to the supernatant, adjust the pH to 1 with hydrochloric acid, incubate at 80°C for 0.5 hour, let stand at room temperature for 2 hours, filter, and dry to obtain Extract 5. The supernatant is retained. The supernatant is allowed to stand at room temperature for 2 days, filtered, and dried to obtain Extract 6. The supernatant is disposed of as wastewater.

[0051] The yields and baicalin contents of extracts 1-6 are shown in Table 1.

[0052] Table 1 Extract content in each step of continuous acid precipitation.

[0053]

[0054] The above results show that five consecutive acid precipitations have almost no adverse effects on the product. The product begins to decrease in the fifth time, and the remaining precipitable baicalin content in the supernatant is only 0.43g. It is known that five cycles of acid precipitation can precipitate 94% of baicalin.

[0055] The results of this experiment show that the method of recycling the supernatant for acid precipitation greatly reduces the time cost and the total amount of wastewater. At the same time, it also ensures that the yield of baicalin is as high as 94% (the mass of baicalin in the extract accounts for the percentage of the mass of baicalin in the corresponding extract).

Claims

1. A method for preparing a scutellaria baicalensis extract by cyclic acid precipitation, characterized in that: The following steps are involved: (1) Scutellaria baicalensis root was extracted twice with water, the ratio of root to water was 1:8-1:15 (g / mL), the extraction temperature was 90°C-100°C, and the extraction time was 1-3 hours to obtain an extract; (2) the extract was divided into five equal parts, and each of the parts was vacuum concentrated to obtain concentrate 1, concentrate 2, concentrate 3, concentrate 4, and concentrate 5. The vacuum concentration conditions were a vacuum degree of 0.07 MPa-0.09 MPa and a temperature between 65°C and 75°C. Concentrate 1 was concentrated to 1 / 3 to 1 / 2 of the original extract volume, and concentrates 2-5 were concentrated to 1 / 5 to 1 / 4 of the original extract volume. (3) The concentrated solution 1 was adjusted to pH 1 with hydrochloric acid, kept warm for 0.5-1.5 hours at a temperature of 75°C-85°C, allowed to stand at room temperature for 2 hours, filtered, and dried to obtain extract 1; (4) adding the concentrated solution 2 to the supernatant of step (3), adjusting the pH to 1 with hydrochloric acid, keeping warm for 0.5-1.5 hours at a temperature of 75°C-85°C, standing at room temperature for 2 hours, filtering, and drying to obtain extract 2; (5) adding the concentrated solution 3 to the supernatant of step (4), adjusting the pH to 1 with hydrochloric acid, keeping warm for 0.5-1.5 hours at a temperature of 75°C-85°C, standing at room temperature for 2 hours, filtering, and drying to obtain extract 3; (6) Add the concentrated solution 4 to the supernatant of step (5), adjust the pH to 1 with hydrochloric acid, keep warm for 0.5-1.5 hours at a temperature of 75°C-85°C, let stand at room temperature for 2 hours, filter, and dry to obtain extract 4; (7) Add the concentrated solution 5 to the supernatant of step (6), adjust the pH to 1 with hydrochloric acid, keep warm for 0.5-1.5 hours at a temperature of 75°C-85°C, let stand at room temperature for 2 hours, filter, and dry to obtain extract 5; (8) The supernatant of step (7) was allowed to stand at room temperature for 1-3 days, filtered, and dried to obtain extract 6; (9) The extracts 1-6 are mixed or stored separately to obtain the Scutellaria baicalensis extract.

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