Flavonoid compounds, methods of making and uses thereof

Abstract

The present application relates to natural bacteriostatic active substance technical field, especially to flavonoids and its preparation method and application. The preparation method of the above-mentioned flavonoids comprises: after the gold cholla is removed thorn, freeze-drying and grinding, the gold cholla powder is obtained; the gold cholla powder is subjected to ultrasonic alcohol extraction and organic membrane filtration in sequence, and the extract mother liquor is obtained; the mother liquor is separated and purified, and the flavonoids are obtained. The present application determines the structure of the bacteriostatic effective component in the gold cholla extract, and correspondingly provides a preparation method of the flavonoids, thereby improving the biological activity and application value of the extract, ensuring the consistency and repeatability of the extract, and providing a high-efficiency and stable natural active substance for the antibacterial field.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of natural bacteriostatic active substances, and particularly relates to a flavonoid compound and a preparation method and application thereof. BACKGROUND

[0002] Echinocactus grusonii is a perennial succulent plant of the genus Echinocactus in the family Cactaceae. Its chemical composition and properties have attracted extensive research and commercial interest. Echinocactus grusonii is rich in various phytochemicals, including polysaccharides, phenolic substances, pigments, triterpenes, and saponins. These components endow Echinocactus grusonii with various biological activities, such as anti-inflammatory, antioxidant, antibacterial, anticancer, anti-atherosclerotic, anti-diabetic, neuroprotective, and intestinal protective properties. Therefore, Echinocactus grusonii has potential applications in the food, health product, and pharmaceutical industries.

[0003] Currently, the extraction methods of cactus polysaccharides mainly include hot water method, acid method, enzyme method, ultrasonic wave method, microwave-assisted method, and microbial method. Although the active components in Echinocactus grusonii have various biological activities, existing research shows that the extracts obtained by traditional extraction methods generally exhibit moderate antibacterial effects, which severely limits their application in the antibacterial field. SUMMARY

[0004] To solve or partially solve the problems in the related art, the present application provides a flavonoid compound and a preparation method and application thereof.

[0005] The present application provides a preparation method of a flavonoid compound, which comprises:

[0006] The spines of Echinocactus grusonii are removed, and then the Echinocactus grusonii is freeze-dried and ground to obtain Echinocactus grusonii powder;

[0007] The Echinocactus grusonii powder is sequentially subjected to ultrasonic alcohol extraction and organic membrane filtration to obtain an extract mother liquor;

[0008] The mother liquor is separated and purified to obtain a flavonoid compound represented by Formula I:

[0009]

[0010] Further, the temperature of the freeze-drying is -40℃ to -20℃, and the time is 42h to 72h.

[0011] Further, the temperature of the ultrasonic alcohol extraction is 45℃ to 55℃, and the time is 1.5h to 3.0h.

[0012] Further, the extract liquid of the ultrasonic alcohol extraction is an ethanol solution with a concentration of 80%, and the solid-liquid ratio of the Echinocactus grusonii powder to the ethanol solution is 1g:(25-45)mL.

[0013] Further, the pore size of the organic membrane is 0.45 mu m.

[0014] Further, the separation and purification specifically are:

[0015] The mother liquor is filtered, silica gel is added to the filtrate, and then vacuum concentration is performed to obtain a stationary phase; the stationary phase is subjected to gradient elution with dichloromethane and methanol as the developing agent, and the elution phase with a gradient of dichloromethane:methanol = 15:1 to dichloromethane:methanol = 5:1 is collected to obtain a crude product; the crude product is subjected to vacuum concentration to obtain the flavonoid compound shown in formula I.

[0016] Further, the temperature of the vacuum concentration is 45 DEG C to 55 DEG C.

[0017] Further, the mass ratio of the mother liquor to silica gel is (10-18):1; and the gradient elution range of the developing agent is dichloromethane:methanol = 100:1 to dichloromethane:methanol = 1:1.

[0018] The application further provides a flavonoid compound, which has a structure as shown in formula I.

[0019]

[0020] The application further provides an application of the flavonoid compound in antibacterial products, wherein the antibacterial products include one or more of cosmetics, medicines, health products and food additives.

[0021] The flavonoid compound and the preparation method thereof can have the following beneficial effects:

[0022] 1) The structure of the antibacterial effective component in the extract of G. stellatum is the flavonoid compound as shown in formula I, and a preparation method of the flavonoid compound is provided accordingly, thereby improving the biological activity and application value of the extract, ensuring the consistency and repeatability of the extract, and providing a high-efficiency and stable natural active substance for the antibacterial field.

[0023] 2) The preparation method performs freeze-drying before ultrasonic extraction of the G. stellatum after removing the spines, reduces the viscosity of the extraction system, makes the extraction process more uniform, and improves the consistency and repeatability of the extraction; in addition, the freeze-drying process is performed at low temperature, avoids the damage of high temperature to the flavonoid compound, and ensures the yield of the flavonoid compound.

[0024] 3) In the preparation method, the extraction liquid of ultrasonic extraction is an alcohol solution, the purity of the flavonoid compound in the mother liquor is higher, and the difficulty of subsequent purification of the flavonoid compound is reduced.

[0025] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application, as claimed. BRIEF DESCRIPTION OF DRAWINGS

[0026] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout and in which:

[0027] Figure 1 is the HPLC liquid chromatogram of the extract mother liquor in Example 1 of the present application;

[0028] Figure 2 is the HPLC liquid chromatogram of the extract mother liquor in Example 1 of the present application;

[0029] Figure 3 is the LC-MS analysis spectrum of the extract product in Example 1 of the present application, with liquid phase retention time of 23.104 min;

[0030] Figure 4 is the HDMS negative ion mode mass spectrum of the extract product in Example 1 of the present application;

[0031] Figure 5 is the HDMS positive ion mode mass spectrum of the extract product in Example 1 of the present application;

[0032] Figure 6 is the HNMR analysis spectrum of the extract product in Example 1 of the present application;

[0033] Figure 7 is the HPLC liquid chromatogram of the extract mother liquor in Comparative Example 1 of the present application;

[0034] Figure 8 is the extract product in Example 1 of the present application against Staphylococcus epidermidis and Malassezia. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0036] The terminology used in the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used in the present application and the following claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0037] It should be understood that, although the terms "first," "second," "third," etc. can be employed in the present application to describe various information, these terms are not intended to denote a particular order or hierarchy. These terms are used merely as labels to identify particular information. For example, a first information can be termed a second information, and similarly, a second information can be termed a first information without departing from the scope of the present application. Therefore, the use of the terms "first," "second," "third," etc. should not be interpreted in their plain and ordinary sense unless otherwise indicated by the context.

[0038] The present inventors consider that the reason why the existing cactus extract has no obvious bacteriostatic effect mainly lies in that: on the one hand, the effective component in the extract that plays a role in bacteriostasis is not clear; on the other hand, the bacteriostatic effect is poor due to the damage to the bacteriostatic effective component in the extraction process.

[0039] Therefore, the present inventors first obtain an extract by a traditional extraction method, and then analyze the main components of the extract to preliminarily determine that the components are flavonoids and the molecular weight range thereof is not more than 400. Based on the analysis result, the present inventors further consider using a method with relatively mild temperature condition and relatively short time to prevent the flavonoids from being damaged during extraction and to improve the yield. Based on this, the present inventors first use ultrasonic extraction method, which is helpful to improve the extraction efficiency. However, the present inventors find through research that the extraction system is very viscous when the Giallo cactus is subjected to ultrasonic extraction.

[0040] 1) The propagation of ultrasonic waves is hindered, and the contact area between the ultrasonic waves and the extract is reduced, thereby reducing the extraction efficiency.

[0041] 2) The flavonoid components are unevenly distributed in the viscous system, which leads to the extraction effect in some areas being not as good as that in other areas, thereby affecting the consistency and repeatability of the extraction.

[0042] 3) The heat generated during the ultrasonic process is difficult to dissipate in time due to the hindering effect of the viscous system, and excessive heat is accumulated in the extraction system, which leads to the thermal decomposition of the flavonoids.

[0043] The inventors of the present application have further found that the problem of too thick extraction system in ultrasonic extraction can be solved by freeze-drying the G. grandiflora and then performing ultrasonic extraction, and the freeze-drying process is performed at a low temperature and does not cause damage to the flavonoids.

[0044] Therefore, the present application considers a method combining freeze-drying and ultrasonic extraction to extract the G. grandiflora, and separates and purifies the extract to obtain flavonoids with better antibacterial effect.

[0045] The present application provides a preparation method of flavonoids, which comprises the following steps:

[0046] The G. grandiflora is freeze-dried after being de-spined and then ground to obtain G. grandiflora powder;

[0047] The G. grandiflora powder is sequentially subjected to ultrasonic alcohol extraction and organic membrane filtration to obtain an extract mother liquor;

[0048] The mother liquor is separated and purified to obtain flavonoids represented by formula I:

[0049]

[0050] In the above preparation method, the G. grandiflora is first de-spined to facilitate subsequent operations. Then, the de-spined G. grandiflora is freeze-dried. Freeze-drying can remove the water in the G. grandiflora and increase the concentration of the extract. Since the process is performed in a low-temperature environment, the flavonoids can be maximally retained and loss thereof in the water removal process can be prevented. More importantly, when the freeze-dried G. grandiflora is subjected to ultrasonic extraction, the viscosity of the extraction system is greatly reduced, which is conducive to improving the efficiency and uniformity of subsequent ultrasonic extraction. In addition, the damage to the flavonoids is reduced, and the difficulty of subsequent purification is reduced.

[0051] In this step, the temperature for freeze-drying is preferably -40℃ to -20℃, and the time is 42h to 72h. Most preferably, the temperature for freeze-drying is -30℃, and the time is 48h. Although the pretreatment of increasing the surface area of the G. grandiflora by slicing before freeze-drying can help to improve the efficiency of freeze-drying, the flavonoids have good water solubility and are prone to loss with water during slicing. Therefore, in the present application, the de-spined G. grandiflora is preferably freeze-dried as a whole. The freeze-dried G. grandiflora is ground to obtain G. grandiflora powder, which can increase the contact area between the sample and the extraction liquid and improve the efficiency of subsequent ultrasonic extraction.

[0052] The powder of G. aurea is obtained and then subjected to ultrasonic extraction. For the extraction liquid, an alcohol solution is selected in this embodiment. Compared with water extraction, the alcohol extraction can obtain a mother liquor with higher purity of flavonoids. Further, the extraction liquid obtained by ultrasonic alcohol extraction is an 80% ethanol solution, and the solid-liquid ratio of G. aurea powder to the ethanol solution is preferably 1 g:(25-45) mL, and most preferably 1 g:30 mL. The ultrasonic alcohol extraction is preferably performed at a temperature of 45-55°C for 1.5-3.0 hours. Most preferably, the ultrasonic temperature is 55°C and the time is 2.5 hours. This condition is beneficial to improve the yield of the mother liquor.

[0053] The mixture after ultrasonic extraction is filtered using an organic membrane to remove solid particles, proteins, polysaccharides and other high molecular substances, so as to improve the purity of flavonoids. The pore size of the organic membrane is preferably 0.45 μm, which is beneficial to retain flavonoids to the maximum extent while filtering out impurities and interfering compounds. The mother liquor containing flavonoids is obtained after organic membrane filtration.

[0054] The main components of the mother liquor are characterized to determine that the main component is a flavonoid compound of formula I.

[0055] The specific characterization method can be as follows:

[0056] The mother liquor is subjected to HPLC analysis to determine that the main chromatographic peak is near 23.1 min.

[0057] The mother liquor is subjected to LC-MS analysis to further analyze and determine that the molecular weight of the compound corresponding to the chromatographic peak at 23.1 min should be about 300.3.

[0058] The mother liquor is subjected to HDMS analysis, and in combination with the mass spectrum data, it is speculated that the molecular formula of the compound is C 16 H 12 O6.

[0059] The mother liquor is subjected to HNMR analysis, and the chemical structure of the compound is finally determined as shown in formula I.

[0060]

[0061] The mother liquor is subjected to separation and purification, and the operation of purification is preferably as follows:

[0062] The mother liquor is filtered, silica gel is added to the filtrate, and then the filtrate is concentrated under reduced pressure to obtain the stationary phase. The stationary phase is gradient eluted with dichloromethane and methanol as the developing agent, and the elution phase with a gradient of dichloromethane:methanol = 15:1 to dichloromethane:methanol = 5:1 is collected to obtain the crude product. The crude product is concentrated under reduced pressure to obtain the flavonoid compound shown in the above formula I. In the above purification process, the first reduced pressure concentration is used to remove the solvent ethanol to obtain a solid precipitate; the second reduced pressure concentration is used to remove the eluent from the solution obtained after chromatographic separation to obtain the pure flavonoid compound product. The temperature of the reduced pressure concentration is preferably 45-55°C to avoid the damage of high temperature to the flavonoid compound. As a preferred embodiment of the present embodiment, the mass ratio of the above mother liquor to silica gel is preferably (10-18):1; the gradient elution range of the developing agent is preferably dichloromethane:methanol = 100:1 to dichloromethane:methanol = 1:1.

[0063] The purified product is analyzed by HPLC, LC-MS, HDMS and HNMR to determine that it is successfully separated from the mother liquor and has the structure of the compound shown in the above formula I.

[0064] Another embodiment of the present application also provides a flavonoid compound with a molecular formula of C 16 H 12 O6, and a structure as shown in formula I:

[0065]

[0066] The flavonoid compound can be prepared according to the above method, and the specific embodiment manner is the same as the foregoing embodiments, which will not be described herein.

[0067] From the above, the flavonoid compound and the preparation method thereof provided by the embodiments of the present application have the following advantages:

[0068] 1) The structure of the bacteriostatic active ingredient in the Mammillaria bombycina extract is determined to be the flavonoid compound shown in formula I, and a preparation method of the flavonoid compound is correspondingly provided, thereby improving the biological activity and application value of the extract, ensuring the consistency and repeatability of the extract, and providing a natural active substance with high efficiency and stability for the antibacterial field.

[0069] 2) The preparation method first performs freeze-drying before ultrasonic extraction of the Mammillaria bombycina after removing the spines, which reduces the viscosity of the extraction system, makes the extraction process more uniform, and improves the consistency and repeatability of the extraction; in addition, the freeze-drying process is performed at low temperature, which avoids the damage of high temperature to the flavonoid compound and ensures the yield of the flavonoid compound.

[0070] 3), the extract liquid of the ultrasonic extraction in the preparation method adopts an alcohol solution, the purity of the flavonoids in the mother liquor is higher, and the difficulty of subsequent purification of the flavonoids is reduced.

[0071] Another embodiment of the present application also provides application of the above-mentioned flavonoids in a bacteriostatic product, wherein the bacteriostatic product comprises one or more of cosmetics, medicines, health products and food additives.

[0072] The technical solutions of the present application are further described below in combination with specific embodiments:

[0073] Embodiment 1

[0074] 1, take the Opuntia dillenii Haw, remove the thorns, and freeze-dry the Opuntia dillenii Haw as a whole, the freeze-drying temperature is-30℃, and the freeze-drying time is 48 h.

[0075] 2, after freeze-drying, use a mortar to grind to obtain Opuntia dillenii Haw powder.

[0076] 3, take 2 g of Opuntia dillenii Haw powder, add 60 ml of 80% ethanol water (volume ratio), and ultrasonically extract at 55℃ for 2.5 hours, then filter with a 0.45 μm organic membrane to obtain 50.87 g of extract mother liquor.

[0077] 4, separation and purification: add 4.5 g of silica gel to the filtered ethanol solution 50.78 g, concentrate under reduced pressure, the concentration temperature is 50℃, to obtain a solid, perform normal phase separation, the developing agent gradient used is dichloromethane:methanol=100:1 to 1:1, the product gradient obtained is dichloromethane:methanol=15:1 to 5:1, and the obtained product is concentrated under reduced pressure, the concentration temperature is 50℃, to obtain the product 0.81 g.

[0078]

Qualitative analysis

[0079] HPLC analysis is performed on the mother liquor obtained in step 3 and the product obtained in step 4, and the HPLC analysis conditions are as follows:

[0080] Analysis equipment: Hitachi full-wavelength liquid phase analysis system

[0081] Mobile phase: A-0.2% formic acid water, B-methanol

[0082] Chromatographic column: C18, 5 μm, 4.6*150 mm

[0083] Detection condition: detection wavelength 360 nm, column temperature 40℃, injection amount 20 μl, flow rate 1.2 ml / min

[0084] The mobile phase gradient condition is shown in Table 1:

[0085] Table 1 Mobile phase gradient conditions

[0086] Time (min) 0 10 20 25 A％ 70 55 45 30 B％ 30 45 55 70

[0087] The HPLC liquid chromatograms of the extract mother solution and the golden oak extract product are shown in 1 and Figure 2 The liquid phase analysis results are shown in Table 2:

[0088] Table 2 HPLC analysis results

[0089]

[0090] Depend on Figure 1-2 As shown in Table 2, the purity of the mother liquor is 43.18%, and the purity of the golden barrel cactus extract product reaches 99.75% after normal phase purification, thus achieving the effect of product purification.

[0091] HPLC analysis revealed that the main chromatographic peak of the mother liquor was near 23.1 min. The product was further analyzed by LC-MS to determine the molecular weight of the chromatographic peak.

[0092] LC-MS analysis conditions are as follows:

[0093] Analytical equipment: Waters mass spectrometer

[0094] Mobile phase: same as HPLC

[0095] Chromatographic column: same as HPLC

[0096] Detection conditions: Same as HPLC

[0097] Mobile phase gradient conditions were the same as those of HPLC

[0098] The LC-MS analysis spectrum of the product is as follows Figure 3 As shown in the figure, it can be seen that the molecular weight of the compound corresponding to the chromatographic peak at 23.1 min should be approximately 300.3.

[0099] The high-resolution mass spectrometry (HDMS) analysis of the golden barrel cactus extract product was continued. The injection volume was increased by the analytical liquid system, and the chromatographic peak with a retention time of 23 minutes was manually collected for further high-resolution mass spectrometry analysis to infer the possible molecular formula. The negative ion mode mass spectrum and the positive ion mode mass spectrum were respectively Figure 4 and Figure 5 As shown,

[0100] The high-resolution mass spectrometry negative ion mode mass spectrum showed that the molecular ion peak of M-1 had an accurate molecular weight of 299.0551, and the molecular ion peak of M+1 had an accurate molecular weight of 301.0707. Referring to the structural characteristics of flavonoids, the elemental composition was limited to CHO, and the most likely molecular formula was inferred to be C 16 H12 O6.

[0101] The HNMR analysis of golden barrel cactus extract was performed, and the HNMR analysis spectrum is as follows: Figure 6 shown.

[0102] The combination of HNMR and HDMS shows that the deviation between the measured values ​​of positive and negative ions and the theoretical values ​​is much less than 10 ppm, with a high degree of match, and the structural formula I is determined to be:

[0103]

[0104] Example 2

[0105] The only difference from Example 1 is:

[0106] In step 3, the ultrasonic temperature was 45° C. and the ultrasonic time was 2.5 hours to obtain 50.11 g of extract mother liquor.

[0107] Example 3

[0108] The only difference from Example 1 is:

[0109] In step 3, the ultrasonic temperature was 55° C. and the ultrasonic time was 1.5 hours to obtain 50.03 g of extract mother liquor.

[0110] It can be seen from Examples 1 to 3 that when the ultrasonic alcohol extraction temperature is 55° C. and the time is 2.5 h, the yield of the mother liquor is the highest, which correspondingly indicates that the yield of flavonoids is the highest.

[0111] Comparative Example 1

[0112] The only difference from Example 1 is:

[0113] The extract in step 3 was 60 ml of water, and 60.78 g of extract mother liquor was obtained.

[0114] The mother liquor of the extract of Comparative Example 1 was subjected to HPLC respectively, and the HPLC spectra were as follows: Figure 7 The analysis results are shown in Table 3. Figure 1 and Figure 7 As shown in Tables 2 and 3, the purity of flavonoids in the mother liquor obtained by alcohol extraction is higher.

[0115] Table 3 HPLC analysis results

[0116]

[0117]

[0118]

Bacterial inhibition experiment

[0119] (I) Experimental steps

[0120] 1. Sample preparation: In the clean bench, weigh 3 parts of the gold extract product prepared in Example 1, each 3 g; add 1000 g, 200 g, and 100 g of sterile water, respectively, and vortex for 1 minute. Place the centrifuge tube in an ultrasonic cleaner for ultrasonic dissolution, centrifuge at 4500 rpm for 30 minutes, and take the supernatant for sterile filtration through a 0.22 micron disposable needle-type sterile filter. The sample is the sample to be tested, and the information of the sample to be tested is shown in Table 4. Store the sample to be tested at 4°C.

[0121] Table 4 Information of the sample to be tested

[0122] Serial number sample concentration 1 Sterile water (negative control) / 2 Ampicillin (positive control) 280mM 3 Golden Echinops Extract 10mM 4 Golden Echinops Extract 50mM 5 Golden Echinops Extract 100mM

[0123] 2. Preparation of indicator bacteria suspension

[0124] Strain activation: the day before, inoculate the test strains (Staphylococcus epidermidis and Malassezia) with LB medium and modified Martin medium at a ratio of 1:1000. Incubate Staphylococcus epidermidis and Malassezia at 36°C±1°C, 150 rpm for 18-24 hours.

[0125] Suspension preparation: measure the absorbance at 600 nm of the activated bacteria solution, and dilute with LB medium and modified Martin medium to OD600 of about 0.6±0.05 (i.e. the concentration of the bacterial suspension is 10 8 CFU / mL)

[0126] Detection plate preparation: heat and dissolve the prepared NA medium and modified Martin agar medium, and cool to 55-60°C (can be incubated in a water bath). Add the prepared indicator bacteria suspension to the medium at an addition amount of 0.1%, mix well, pour into sterile plates, gently shake the plates to evenly spread, and use after solidification.

[0127] 3. Measurement

[0128] Sample measurement: in the detection plate containing the indicator bacteria, use a 1 mL sterile gun head to punch 5 holes, and measure 100 microliters of the sample, slowly add it to the hole, and place the plate containing Staphylococcus epidermidis and Malassezia in a 36°C±1°C incubator, and incubate vertically until the inhibition zone is clear. Measure the diameter of the inhibition zone with a caliper.

[0129] Control measurement: take sterile water as a blank control, and take 100 mg / mL ampicillin as a positive control. The steps are the same as sample measurement.

[0130] (II) Experimental results

[0131] The inhibition effect of the gold extract product prepared in Example 1 on Staphylococcus epidermidis and Malassezia is shown in the physical diagram Figure 8 as shown, Figure 8 A + " represents ampicillin (positive control), "A + " represents, "H2O" represents sterile water (negative control), "10" represents gold extract (10 mM), "50" represents gold extract (50 mM), "100" represents gold extract (100 mM). The antibacterial effect data are shown in Table 5 and Table 6, respectively.

[0132] Table 5 Antibacterial effect of gold extract product on Staphylococcus epidermidis

[0133] Serial number sample Diameter of inhibition zone (mm) 1 Sterile water (negative control) / 2 Ampicillin (positive control) 15.4 3 Echinops chinensis extract (10mM) 9.8 4 Echinops chinensis extract (50mM) 12.4 5 Echinops chinensis extract (100mM) 13.7

[0134] Table 6 Antibacterial effect of gold extract product on Malassezia

[0135] Serial number sample Diameter of inhibition zone (mm) 1 Sterile water (negative control) / 2 Ampicillin (positive control) 11.5 3 Echinops chinensis extract (10mM) 8.3 4 Echinops chinensis extract (50mM) 11.6 5 Echinops chinensis extract (100mM) 12.5

[0136] From the results of the antibacterial experiment, it can be seen that the purified gold extract (i.e. the flavonoid compound shown in the above formula I) has good antibacterial effect; and as the concentration of the gold extract increases, the antibacterial effect also increases.

[0137] The above has described various embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical application, or improvement to the technology in the market, or to enable other ordinary skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing flavonoid compounds, characterized in that: include: The thorns of the golden ebony cactus are removed, freeze-dried, and then ground to obtain the golden ebony cactus powder; The equisetum cactus powder is subjected to ultrasonic alcohol extraction and organic membrane filtration in sequence to obtain an extract mother liquor; The mother liquor is separated and purified to obtain the flavonoid compound represented by formula I:

2. The preparation method according to claim 1, characterized in that The freeze-drying temperature is -40°C to -20°C, and the time is 42h to 72h.

3. The preparation method according to claim 1, characterized in that The temperature of the ultrasonic alcohol extraction is 45° C. to 55° C., and the time is 1.5 h to 3.0 h.

4. The preparation method according to claim 1, characterized in that The ultrasonic alcohol extraction extract is an ethanol solution with a concentration of 80%, and the material-liquid ratio of the golden equisetum cactus powder to the ethanol solution is 1g: (25-45)mL.

5. The preparation method according to claim 1, characterized in that The pore size of the organic membrane is 0.45 μm.

6. The preparation method according to claim 1, characterized in that The separation and purification specifically comprises: filtering the mother liquor; adding silica gel to the filtrate, and then concentrating under reduced pressure to obtain a stationary phase; gradient eluting the stationary phase with dichloromethane and methanol as developing solvents, collecting the elution phase with a gradient of dichloromethane:methanol = 15:1 to dichloromethane:methanol = 5:1 to obtain a crude product; and concentrating the crude product under reduced pressure to obtain the flavonoid compound represented by formula I.

7. The preparation method according to claim 6, characterized in that The temperature of the reduced pressure concentration is 45°C to 55°C.

8. The preparation method according to claim 7, characterized in that The mass ratio of the mother liquor to the silica gel is (10-18):1; the gradient elution range of the developing solvent is dichloromethane:methanol=100:1 to dichloromethane:methanol=1:

1.

9. A flavonoid compound, characterized in that Its structure is shown in Formula I:

10. Use of the flavonoid compound of claim 9 in an antibacterial product, wherein the antibacterial product comprises one or more of cosmetics, medicines, health products and food additives.

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