Scutellaria baicalensis extract with antibacterial effect and preparation method thereof

Abstract

The invention relates to the technical field of bacteriostatic agents, in particular to a radix scutellariae extract with a bacteriostatic effect and a preparation method. The preparation method comprises the following steps: weighing scutellaria baicalensis root powder, putting the scutellaria baicalensis root powder into a polyethylene bag, adding a hydroxypropyl-beta-cyclodextrin aqueous solution into the bag, sealing by a sealing machine, and putting a sample into ultrahigh pressure equipment. The preparation method comprises the following steps: after ultrahigh-pressure extraction is completed, transferring a material into a centrifugal tube, centrifuging to take supernate which is an extracting solution of baicalin and baicalein, heating and stirring the supernate in a water bath kettle, converting the baicalin into the baicalein under the action of endogenous enzyme, and performing vacuum freeze drying after the reaction is completed to obtain the hydroxypropyl-beta-cyclodextrin clathrate extract. According to the invention, baicalin and baicalein in scutellaria baicalensis are simultaneously extracted by adopting an ultrahigh pressure assisted hydroxypropyl-beta-cyclodextrin aqueous solution, and an extract (UP-HP-beta-CD extract) clathrated by hydroxypropyl-beta-cyclodextrin is prepared by cooperating an endogenous enzyme enzymolysis method with a hydroxypropyl-beta-cyclodextrin clathration technology. The extraction efficiency, solubility, biological activity and other properties of effective components in scutellaria baicalensis are improved, the antibacterial effect of the scutellaria baicalensis extract is further improved, and the prepared scutellaria baicalensis antibacterial extract is simple in preparation method, easy and convenient to operate, environmentally friendly, safe, capable of saving energy in process, good in environmental benefit and capable of being applied to industrial large-scale production.

Description

Technical Field

[0001] The present invention relates to the technical field of antibacterial agents, in particular to a scutellaria baicalensis extract with antibacterial effect and a preparation method thereof. Background Art

[0002] Scutellaria baicalensis Georgi, Lamiaceae, is a perennial herb. The stem of Scutellaria baicalensis is generally 30 to 120 cm high, growing upright and branched. The stem is quadrangular with fine stripes and covered with white soft hairs, especially on the ridges where the hairs are more dense. The leaves are usually opposite, sessile or nearly sessile, lanceolate to linear-lanceolate, 1.5 to 4.5 cm long and 0.5 to 1.2 cm wide. The upper surface is dark green, glabrous or sparsely covered with appressed fine hairs, and the lower surface is light green with appressed short soft hairs. The flowers are in racemes, terminal, and the flowers are arranged relatively closely and tend to one side. The calyx is bilabiate, and the corolla is purple, purplish-red, or blue, 2.3 to 3 cm long. The fruit is a small, ovoid nut, approximately 1.5 mm long, and dark brown. The root of Scutellaria baicalensis is very distinctive, generally conical in shape, with a relatively thick taproot reaching approximately 2 cm in diameter. The root system penetrates deep into the soil, often reaching over 30 cm. The outer bark of the root is tan or dark brown with longitudinal wrinkles and a relatively hard texture. The cross section is yellow with a reddish-brown center. Flowering occurs from July to August, and fruiting occurs from August to September. Scutellaria baicalensis, included in the Chinese Pharmacopoeia and used for over 2,000 years, is one of the most commonly used herbs in traditional Chinese medicine. It grows in grassy areas on sunny slopes and is primarily distributed in China, Mongolia, the Korean Peninsula, Japan, and Russia.

[0003] Scutellaria baicalensis contains a diverse range of chemical components, including organic acids, terpenoid derivatives, alkaloids, sterols, polysaccharides, and various trace elements. Flavonoids are the primary active ingredients in Scutellaria baicalensis, with baicalin and baicalein being the two most well-known flavonoids. As a traditional Chinese medicinal material, Scutellaria baicalensis extracts exhibit significant antibacterial activity against bacteria such as Escherichia coli, Propionibacterium acnes, and Staphylococcus aureus. Current conventional extraction methods often suffer from long extraction times, high extraction temperatures, low efficiency, and complex procedures. Baicalin is a glycoside of baicalein, and baicalein is aglycone of baicalein. Aglycones often have more potent functional properties than glycosides. Baicalein is often prepared by acid hydrolysis of baicalin, which uses large amounts of organic acid and poses a significant environmental risk. Using water as the hydrolysis solvent, the hydrolysis efficiency is low due to baicalin's low solubility in water. Therefore, a new extraction method needs to be proposed to solve the above problems. Summary of the Invention

[0004] Based on the shortcomings of the existing technology, the present invention provides an extract after inclusion of hydroxypropyl-β-cyclodextrin and a preparation method. On the basis of adopting a new ultra-high pressure extraction technology, hydroxypropyl-β-cyclodextrin is added to increase the stability and solubility of natural ingredients and enhance the antibacterial effect of the extract, so as to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for preparing a Scutellaria baicalensis extract having an antibacterial effect, comprising the following steps:

[0006] S1: Pretreatment: Grind the dried root of Scutellaria baicalensis and pass it through a 40-mesh sieve. Mix the dried root powder of Scutellaria baicalensis and hydroxypropyl-β-cyclodextrin in a certain proportion, add water and stir thoroughly to obtain a mixed solution.

[0007] S2: Extraction: Place the dried root powder of Scutellaria baicalensis in a polyethylene bag. Add a hydroxypropyl-β-cyclodextrin aqueous solution to the bag, seal it with a sealing machine, and place the sample in an ultrahigh pressure device. Set the ultrahigh pressure device parameters. After the ultrahigh pressure extraction is complete, transfer the material to a centrifuge tube and centrifuge to obtain the supernatant, which is the extract of baicalin and baicalein.

[0008] S3: Enzymatic hydrolysis: The supernatant is placed in a water bath and heated with stirring. Baicalin is converted into baicalein by the endogenous enzymes of Scutellaria baicalensis. During the conversion process, baicalein is encapsulated by a hydroxypropyl-β-cyclodextrin aqueous solution.

[0009] S4: Preparation of the extract after inclusion of hydroxypropyl-β-cyclodextrin: The solution obtained by enzymatic hydrolysis is the extract after inclusion of hydroxypropyl-β-cyclodextrin, and the extract is vacuum freeze-dried to obtain the extract after inclusion of hydroxypropyl-β-cyclodextrin.

[0010] Preferably, the dried root of Scutellaria baicalensis in S1 is crushed and passed through a 40-60 mesh sieve, the solvent is a hydroxypropyl-β-cyclodextrin aqueous solution, the solid-liquid ratio of the Scutellaria baicalensis root powder to the hydroxypropyl-β-cyclodextrin aqueous solution is 1 g: (10-35) mL; and the concentration of the hydroxypropyl-β-cyclodextrin aqueous solution is 2-12%.

[0011] Preferably, the ultrahigh pressure extraction pressure in S2 is 50 to 350 MPa, and the pressure holding time is 0.5 to 11 min.

[0012] Preferably, the centrifugal separation speed of the Scutellaria baicalensis extract after ultrahigh pressure in S2 is 4000-6000 r / min; and the separation time is 5-10 min.

[0013] Preferably, the enzyme in S3 is an endogenous enzyme in the Scutellaria baicalensis plant, and the enzymatic hydrolysis temperature is 25 to 65° C. for 10 to 180 min.

[0014] The present invention also provides the following technical solution: a scutellaria baicalensis extract with antibacterial effect, which is prepared by the above-mentioned preparation method of the scutellaria baicalensis extract with antibacterial effect.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention adopts ultrahigh pressure assisted hydroxypropyl-β-cyclodextrin inclusion technology to simultaneously extract baicalin and baicalein from the scutellaria baicalensis plant, and converts baicalin into baicalein under the action of endogenous enzymes to prepare a scutellaria baicalensis extract with antibacterial effect, thereby improving the extraction efficiency, solubility, biological activity, stability and other properties of the effective ingredients in scutellaria baicalensis, and increasing the antibacterial activity of the scutellaria baicalensis extract.

[0017] 2. Cyclodextrin and its derivatives have been used as excipients in various dosage forms of traditional Chinese medicine, such as tablets, pills, and injections. Cyclodextrin is safe and non-toxic and can form inclusion complexes with poorly soluble drugs. During the extraction of plant active ingredients, cyclodextrin can include some poorly soluble components, thereby improving their stability, solubility, and bioavailability. Existing studies have shown that cyclodextrin can include baicalin and baicalein to improve their water solubility and bioavailability. Compared with common β-cyclodextrin, the hydroxyl group of hydroxypropyl-β-cyclodextrin is replaced by hydroxypropyl. This structural change significantly improves its water solubility and helps dissolve more hydrophobic drugs. While ultrahigh pressure assisted extraction of hydroxypropyl-β-cyclodextrin aqueous solution, endogenous enzymes were used to hydrolyze baicalin in the scutellaria extract into baicalein, while enriching baicalein.

[0018] 3. Baicalein has poor solubility in aqueous phases or biofilms, which limits its penetration and diffusion into bacterial cells, affecting its antibacterial effect. The formation of inclusion complexes can alter the solubility of baicalein, increasing its solubility in water and allowing it to diffuse more easily in aqueous environments, approaching and penetrating bacterial cell walls and membranes, and reaching the cells to exert its antibacterial effects. Traditional extraction methods, when performed at higher temperatures, can cause some heat-sensitive antibacterial components to decompose or deteriorate, reducing their antibacterial activity. Extracts encapsulated with hydroxypropyl-β-cyclodextrin protect the antibacterial components from high temperatures at low temperatures, preserving their activity. Traditional microwave and reflux extraction methods may have low extraction efficiency for some poorly soluble antibacterial components, resulting in relatively low levels of these components in the extract. In summary, extracts encapsulated with hydroxypropyl-β-cyclodextrin exhibit excellent antibacterial activity and are superior to other extraction methods.

[0019] 4. The present invention provides a new production technology for preparing Scutellaria baicalensis extract with antibacterial effect, which provides guidance for the development direction of industrial green and healthy production of new Scutellaria baicalensis extract.

[0020] 5. The preparation method of the present invention is simple and easy to operate; the materials used are all edible, green and safe; the process saves energy, has good environmental benefits, greatly saves manpower and material resources, and can be applied to large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Comparison of different extraction methods before and after dissolution in Application Example 1

[0022] Figure 2 Inhibitory effects of different extraction methods on Escherichia coli

[0023] Figure 3 Inhibitory effects of different extraction methods on Propionibacterium acnes

[0024] Figure 4 MIC experimental diagram of different extraction methods for Escherichia coli

[0025] Figure 5 MIC experimental diagram of different extraction methods on Propionibacterium acnes

[0026] Figure 6 MBC test diagram of extracts extracted by different methods on Escherichia coli and Propionibacterium acnes DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0028] The present invention provides a technical solution: a scutellaria baicalensis extract with antibacterial effect and a preparation method thereof, the preparation method comprising the following steps:

[0029] S1: Pretreatment: Grind the dried root of Scutellaria baicalensis and pass it through a 40-mesh sieve. Mix the dried root powder of Scutellaria baicalensis and hydroxypropyl-β-cyclodextrin in a certain proportion, add water and stir thoroughly to obtain a mixed solution.

[0030] S2: Extraction: Place the dried root powder of Scutellaria baicalensis in a polyethylene bag. Add a hydroxypropyl-β-cyclodextrin aqueous solution to the bag, seal it with a sealing machine, and place the sample in an ultrahigh pressure device. Set the ultrahigh pressure device parameters. After the ultrahigh pressure extraction is complete, transfer the material to a centrifuge tube and centrifuge to obtain the supernatant, which is the extract of baicalin and baicalein.

[0031] S3: Enzymatic hydrolysis: The supernatant is placed in a water bath and heated with stirring. Baicalin is converted into baicalein by the endogenous enzymes of Scutellaria baicalensis. During the conversion process, baicalein is encapsulated by a hydroxypropyl-β-cyclodextrin aqueous solution.

[0032] S4: Preparation of the extract after inclusion of hydroxypropyl-β-cyclodextrin: The solution obtained by enzymatic hydrolysis is the extract after inclusion of hydroxypropyl-β-cyclodextrin, and the extract is vacuum freeze-dried to obtain the extract after inclusion of hydroxypropyl-β-cyclodextrin.

[0033] In S1, the ratio of the scutellaria baicalensis solution to the hydroxypropyl-β-cyclodextrin aqueous solution is preferably 1:(20-35), more preferably 1:20. The concentration of the hydroxypropyl-β-cyclodextrin is preferably 2-12%, more preferably 6-12%. The hydroxypropyl-β-cyclodextrin can effectively include the active ingredient in the scutellaria baicalensis, and cooperate with the enzymatic hydrolysis process to convert baicalin into baicalein, thereby increasing the solubility of the active ingredient and thereby enhancing the antibacterial effect of the active ingredient.

[0034] In S2, the ultrahigh pressure extraction pressure is preferably 50-350 MPa, more preferably 100-350 MPa; the ultrahigh pressure holding time is preferably 0.5-11 min, more preferably 1-11 min; the scutellaria baicalensis extract is centrifuged at a speed of 4000-6000 r / min, more preferably 5000-6000 r / min, and the centrifugation time is 5-10 min, more preferably 8-10 min;

[0035] S1 and S2 are ultra-high pressure assisted hydroxypropyl-β-cyclodextrin aqueous solution for the simultaneous extraction of baicalin and baicalein from Scutellaria baicalensis, for the preparation of Scutellaria baicalensis extract.

[0036] In S3, the enzymatic hydrolysis temperature is preferably 30-80° C., more preferably 40-60° C.; the enzymatic hydrolysis time is preferably 30-180 min, more preferably 100-150 min.

[0037] S3 and S4 are steps of converting baicalin in the scutellaria baicalensis extract into baicalein under the action of endogenous enzymes, and using a hydroxypropyl-β-cyclodextrin aqueous solution to encapsulate baicalein during the conversion process, thereby preparing a scutellaria baicalensis extract with antibacterial effect.

[0038] The scutellaria baicalensis extract prepared by the present invention has an antibacterial effect. The endogenous enzymes in the scutellaria baicalensis are inactivated during high-temperature extraction, but the endogenous enzymes are not inactivated during ultrahigh-pressure extraction under low-temperature conditions. During the extraction process, the conversion of baicalin to baicalein is in a continuous state. When optimizing the extraction process, the total baicalein index is added. The calculation formula for the total baicalein concentration is:

[0039]

[0040] Where: Y is the total baicalein concentration (mg / mL); B1 is the baicalin concentration (mg / mL); M1 is the relative molecular mass of baicalin; M2 is the relative molecular mass of baicalein; B2 is the baicalein concentration (mg / mL).

[0041] The scutellaria baicalensis extract with antibacterial effect prepared by the present invention has an inhibition zone diameter of 23.15±0.25 mm for Escherichia coli and an inhibition zone diameter of 22.55±0.26 mm for Propionibacterium acnes when the total baicalein concentration is 5 mg / mL.

[0042] The scutellaria baicalensis extract with antibacterial effect prepared by the present invention has a minimum inhibitory concentration of 0.02±0.01 mg / mL against Escherichia coli and a minimum inhibitory concentration of 0.04±0.01 mg / mL against Propionibacterium acnes.

[0043] The scutellaria baicalensis extract with antibacterial effect prepared by the present invention has a minimum bactericidal concentration of 0.08±0.01 mg / mL for Escherichia coli and a minimum bactericidal concentration of 0.16±0.01 mg / mL for Propionibacterium acnes.

[0044] The preparation method provided by the invention is simple, has a mild reaction, and the materials and solvents used in the preparation are non-toxic, has good environmental benefits, and can be applied to factory production.

[0045] In the present invention, the excipient of the scutellaria baicalensis extract with antibacterial effect is an excipient acceptable in the food industry. The present invention has no particular limitation on the type of the excipient acceptable in the food industry, and any excipient well known to those skilled in the art can be used.

[0046] The antibacterial effect of the scutellaria baicalensis extract prepared by the present invention is poor in solubility of baicalein in aqueous phases or biofilms, which limits its penetration and diffusion into bacterial cells, affecting the antibacterial effect. The formation of inclusion complexes can alter the solubility of baicalein, increasing its solubility in water and making it easier to diffuse in aqueous environments, approaching and penetrating bacterial cell walls and membranes, and reaching the cells to exert its antibacterial effect. Due to its excellent solubility, biological activity, and safety, the scutellaria baicalensis extract is expected to have broad market development prospects.

[0047] Example 1

[0048] 1. Grind the dried root of Scutellaria baicalensis and pass it through a 40-mesh sieve. Weigh 1 g of the dried root powder of Scutellaria baicalensis and put it into a polyethylene bag. Add 10% hydroxypropyl-β-cyclodextrin aqueous solution and mix well according to a ratio of 1:20 (g:mL). Seal the bag with a sealing machine.

[0049] 2. Place the sample in an ultrahigh pressure device and set the required parameters: extraction pressure: 100 MPa; pressure holding time: 1 minute. After the ultrahigh pressure extraction is completed, transfer the material to a centrifuge tube and centrifuge at 5000 rpm for 10 minutes to obtain the supernatant and discard the residue. This supernatant is the extract of baicalin and baicalein.

[0050] 3. Heat the supernatant in a 45°C water bath and stir for 180 minutes. Baicalin will be converted into baicalein by the endogenous enzymes of Scutellaria baicalensis. During the conversion process, baicalein will be included in the hydroxypropyl-β-cyclodextrin aqueous solution.

[0051] 4. The solution obtained by enzymatic hydrolysis is an extract after hydroxypropyl-β-cyclodextrin inclusion, and the extract is vacuum freeze-dried to obtain an extract after hydroxypropyl-β-cyclodextrin inclusion.

[0052] 5. The extract after inclusion in hydroxypropyl-β-cyclodextrin was dissolved in water, and the diameter of the inhibition zone for Escherichia coli was measured to be 23.15 mm, the minimum inhibitory concentration was 0.02 mg / mL, and the minimum bactericidal concentration was 0.08 mg / mL. The diameter of the inhibition zone for Propionibacterium acnes was 22.55 mm, the minimum inhibitory concentration was 0.04 mg / mL, and the minimum bactericidal concentration was 0.16 mg / mL.

[0053] Example 2

[0054] 1. Grind the dried root of Scutellaria baicalensis and pass it through a 40-mesh sieve. Weigh 1 g of the dried root powder into a polyethylene bag. Add 10% hydroxypropyl-β-cyclodextrin aqueous solution and mix well at a ratio of 1:20 (g:mL). Seal the bag with a sealing machine.

[0055] 2. Place the sample in an ultrahigh pressure device and set the required parameters: extraction pressure: 100 MPa; pressure holding time: 1 minute. After the ultrahigh pressure extraction is completed, transfer the material to a centrifuge tube and centrifuge at 5000 rpm for 10 minutes to obtain the supernatant and discard the residue. This supernatant is the extract of baicalin and baicalein.

[0056] 3. Heat the supernatant in a 50°C water bath and stir for 120 minutes. Baicalin will be converted into baicalein by the endogenous enzymes of Scutellaria baicalensis. During the conversion process, baicalein will be included in the hydroxypropyl-β-cyclodextrin aqueous solution.

[0057] 4. The solution obtained by enzymatic hydrolysis is an extract after hydroxypropyl-β-cyclodextrin inclusion, and the extract is vacuum freeze-dried to obtain an extract after hydroxypropyl-β-cyclodextrin inclusion.

[0058] 5. The extract after inclusion in hydroxypropyl-β-cyclodextrin was dissolved in water, and the diameter of the inhibition zone for Escherichia coli was measured to be 24.23 mm, the minimum inhibitory concentration was 0.02 mg / mL, and the minimum bactericidal concentration was 0.09 mg / mL. The diameter of the inhibition zone for Propionibacterium acnes was 23.27 mm, the minimum inhibitory concentration was 0.04 mg / mL, and the minimum bactericidal concentration was 0.15 mg / mL.

[0059] Example 3

[0060] 1. Grind the dried root of Scutellaria baicalensis and pass it through a 40-mesh sieve. Weigh 1 g of the dried root powder into a polyethylene bag. Add 10% hydroxypropyl-β-cyclodextrin aqueous solution and mix well at a ratio of 1:20 (g:mL). Seal the bag with a sealing machine.

[0061] 2. Place the sample in an ultrahigh pressure device and set the required parameters: extraction pressure: 150 MPa; holding time: 2 minutes. After the ultrahigh pressure extraction is completed, transfer the material to a centrifuge tube and centrifuge at 5000 rpm for 10 minutes to obtain the supernatant and discard the residue. This supernatant is the extract of baicalin and baicalein.

[0062] 3. Place the supernatant in a 50°C water bath and heat with stirring for 120 minutes. Baicalin will be converted into baicalein by the endogenous enzymes of Scutellaria baicalensis. During the conversion process, baicalein will be included in the hydroxypropyl-β-cyclodextrin aqueous solution to improve its water solubility and enhance its antibacterial activity.

[0063] 4. The solution obtained by enzymatic hydrolysis is an extract after hydroxypropyl-β-cyclodextrin inclusion, and the extract is vacuum freeze-dried to obtain an extract after hydroxypropyl-β-cyclodextrin inclusion.

[0064] 5. The extract after inclusion in hydroxypropyl-β-cyclodextrin was dissolved in water, and the diameter of the inhibition zone for Escherichia coli was measured to be 23.56 mm, the minimum inhibitory concentration was 0.02 mg / mL, and the minimum bactericidal concentration was 0.08 mg / mL. The diameter of the inhibition zone for Propionibacterium acnes was 24.04 mm, the minimum inhibitory concentration was 0.05 mg / mL, and the minimum bactericidal concentration was 0.16 mg / mL.

[0065] The following test example is described using the analysis of the extract after inclusion of hydroxypropyl-β-cyclodextrin prepared in Example 1 as an example:

[0066] Test Example 1

[0067] The baicalin and baicalein contents of the scutellaria baicalensis extract with antibacterial activity prepared in Example 1 were tested by the following method:

[0068] (1) HPLC detection conditions for baicalin and baicalein

[0069] The chromatographic column was a Diamonsil C18 reverse phase column (250 mm × 4.6 mm, 5 μm), the mobile phase was methanol: 0.2% phosphoric acid aqueous solution = 60:40 (V:V), the detection wavelength was 280 nm, the column temperature was 30°C, the flow rate was 1.0 mL / min, and the single injection volume was 10 μL.

[0070] Establishment of standard curve of baicalin and baicalein: 5 mg of baicalin and baicalein were accurately weighed and placed in a 10 mL volumetric flask. Methanol was added to dissolve and dilute to the scale line. Shake well to obtain a reference stock solution containing 500 μg / ml of baicalin and baicalein. Baicalin and baicalein were diluted with methanol to concentrations of 7.8, 15.6, 31.3, 62.5, 125, 250, and 500 μg / ml. The injection volume was 10 μL / time. The samples were passed through a 0.22 μm organic filter membrane and detected by HPLC. The standard curves were drawn with concentration as the horizontal axis and peak area as the vertical axis, and the regression equation and R2 were calculated.

[0071] (2) Preparation of sample solution

[0072] Prepare samples with different solvents, mix them evenly with the root of Scutellaria baicalensis, put them into polyethylene bags, seal them and put them into ultra-high pressure equipment. The ultra-high pressure equipment runs to process the samples. After taking out the samples, the extract is placed in a centrifuge tube and centrifuged at 5000 rpm for 10 minutes to obtain the supernatant. The residue is discarded and the solution is filtered through a 0.22 μm organic filter membrane to obtain the sample solution to be tested.

[0073] Test Example 2

[0074] In a clean bench, sterilize the prepared agar medium and pour it into disposable culture plates, approximately 20 mL per plate. Allow to solidify until ready to use. Pipette 100 μL of the diluted bacterial solution and spread evenly across the plate. Place an Oxford cup vertically on the surface of the culture medium, pressing gently to ensure it is secure. Add 200 μL of each extract sample to the cup. Incubate in a 37°C incubator for 24 hours. Observe the inhibition zones and measure their diameters. The center is normal saline, No. 1 is the 70% ethanol reflux extract, No. 2 is the 70% ethanol microwave extract, No. 3 is the water reflux extract, No. 4 is the water microwave extract, and No. 5 is the UP-HP-β-CD extract.

[0075] The diameters of the inhibition zones of the extracts obtained by different extraction methods against Escherichia coli are shown in Table 1.

[0076]

[0077] The inhibition zone diameters of the extracts extracted by different extraction methods against Propionibacterium acnes are shown in Table 2.

[0078]

[0079] Test Example 3

[0080] The extract was diluted with liquid culture medium using the half-fold dilution method. In a 96-well plate, columns 1-10 were designated as experimental groups (100 μL of diluted sample and 100 μL of diluted test bacterial solution); column 11 was designated as a growth control well (100 μL of liquid culture medium and 100 μL of diluted test bacterial solution); and column 12 was designated as a blank control (200 μL of liquid culture medium). The plates were incubated at 37°C for 24 hours. Turbidity was measured at 600 nm using a microplate reader, and the minimum inhibitory concentration (MIC) was determined based on visual observation, as shown in Table 3.

[0081]

[0082] The MIC and high-concentration bacterial solutions were inoculated into solid culture medium and cultured at 37°C for 24 h. The colony growth was observed and the lowest concentration at which no colonies were visible was recorded, i.e., the minimum bactericidal concentration (Table 4).

[0083]

[0084] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations that come within the meaning and range of equivalents of the claims are intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0085] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A scutellaria baicalensis extract with antibacterial effect and a preparation method thereof, characterized in that: The following steps are involved: S1： Pretreatment: The dried root of Scutellaria baicalensis is crushed and passed through a 40-mesh sieve. The dried root powder of Scutellaria baicalensis and hydroxypropyl-β-cyclodextrin are mixed in a certain proportion, and water is added and stirred thoroughly to obtain a mixed solution. S2: Extraction: Place the dried root powder of Scutellaria baicalensis in a polyethylene bag. Add a hydroxypropyl-β-cyclodextrin aqueous solution to the bag, seal it with a sealing machine, and place the sample in an ultrahigh pressure device. Set the ultrahigh pressure device parameters. After the ultrahigh pressure extraction is complete, transfer the material to a centrifuge tube and centrifuge to obtain the supernatant, which is the extract of baicalin and baicalein. S3: Enzymatic hydrolysis: The supernatant is placed in a water bath and heated with stirring. Baicalin is converted into baicalein by the endogenous enzymes of Scutellaria baicalensis. During the conversion process, baicalein is encapsulated by a hydroxypropyl-β-cyclodextrin aqueous solution. S4: Preparation of the extract after inclusion of hydroxypropyl-β-cyclodextrin: The solution obtained by enzymatic hydrolysis is the extract after inclusion of hydroxypropyl-β-cyclodextrin, and the extract is vacuum freeze-dried to obtain the extract after inclusion of hydroxypropyl-β-cyclodextrin.

2. The method for preparing the Scutellaria baicalensis extract with antibacterial effect according to claim 1, wherein: The dried root of Scutellaria baicalensis in S1 was crushed and passed through a 20-120 mesh sieve.

3. The method for preparing the Scutellaria baicalensis extract with antibacterial effect according to claim 1, wherein: The solvent is a hydroxypropyl-β-cyclodextrin aqueous solution, the solid-liquid ratio of the dried scutellaria root powder to the hydroxypropyl-β-cyclodextrin aqueous solution is 1g:(10-35)mL; the concentration of the hydroxypropyl-β-cyclodextrin aqueous solution is 2-12%.

4. The method for preparing the Scutellaria baicalensis extract with antibacterial effect according to claim 1, wherein: The extraction pressure of the ultrahigh pressure in S2 is 50-350 MPa, and the pressure holding time is 0.5-11 min.

5. The method for preparing the Scutellaria baicalensis extract with antibacterial effect according to claim 1, wherein: The rotation speed of the centrifugal separation of the Scutellaria baicalensis extract after ultrahigh pressure in S2 is 4000-6000 r / min; the time of the centrifugal separation is 5-10 minutes.

6. The method for preparing the Scutellaria baicalensis extract with antibacterial effect according to claim 1, wherein: The enzymatic hydrolysis treatment in S3 refers to the endogenous enzymes in the Scutellaria baicalensis plant; the enzymatic hydrolysis conditions are enzymatic hydrolysis temperature of 25 to 65° C. and enzymatic hydrolysis time of 10 to 180 min.

7. The method for preparing the Scutellaria baicalensis extract with antibacterial effect according to claim 1, wherein: The scutellaria baicalensis extract in S4 is vacuum freeze-dried to obtain an extract after inclusion of hydroxypropyl-β-cyclodextrin.

8. A scutellaria baicalensis extract having an antibacterial effect, characterized in that: The extract is prepared by the method for preparing the scutellaria baicalensis extract according to any one of claims 1 to 7.

9. The hydroxypropyl-β-cyclodextrin inclusion extract according to claim 1, characterized in that It has an inhibitory effect on Escherichia coli and Propionibacterium acnes.

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