Composite extract of ampelopsis grossedentata leaves as well as preparation method and application of composite extract

Abstract

The invention relates to the field of natural flavone extraction, in particular to a composite extract of ampelopsis grossedentata leaves as well as a preparation method and application of the composite extract. The preparation method of the composite extract of the ampelopsis grossedentata leaves comprises the following steps: step 1, cleaning and crushing the silybum marianum, the ampelopsis grossedentata leaves, the pineapples and the longan to obtain an initial mixed plant; 2, mixing the initial mixed plant with water, and treating under an ultrasonic power condition to obtain an ultrasonic treatment substance; 3, treating the ultrasonic treatment object under a microwave condition to obtain a microwave treatment object; step 4, adding acetobacter aceti, bacillus subtilis and white rot fungi into the microwave treated material, and fermenting to obtain a fermented mixture; and step 5, centrifuging, and collecting supernate to obtain the composite extract of the ampelopsis grossedentata leaves. The composite extract of the ampelopsis grossedentata leaves can improve the extraction efficiency of flavonoid substances, and has remarkable anti-inflammatory and anti-oxidation effects.

Description

Technical Field

[0001] The present application relates to the field of natural flavonoid extraction, and more specifically, to a composite extract of Ampelopsis grossedentata leaves and a preparation method and application thereof. Background Art

[0002] Flavonoids are widely found in many plants in nature. They have multiple biological activities such as anti-oxidation, anti-inflammatory, anti-tumor, hypoglycemic, and hypolipidemic, and have a significant protective effect on human health. However, flavonoids cannot be synthesized in the human body and are completely dependent on food intake. In addition, their metabolism rate in the body is relatively fast, which makes it difficult for flavonoids taken from the daily diet to meet the full amount of human health needs. Therefore, finding plant resources rich in flavonoids from nature, extracting and purifying these natural active ingredients, has become a research hotspot in the current field of medicine and health food.

[0003] The current methods for extracting flavonoids have many defects, such as low extraction efficiency, high cost, and environmental unfriendliness, which limit the large-scale production and wide application of flavonoids. Therefore, there is still room for improvement. Summary of the invention

[0004] In order to improve the extraction efficiency of flavonoids, the present application provides a composite extract of Ampelopsis grossedentata leaves and a preparation method and application thereof.

[0005] In a first aspect, the present application provides a method for preparing a composite extract of Ampelopsis grossedentata leaves, using the following technical solution: A method for preparing a composite extract of Ampelopsis grossedentata leaves comprises the following steps: Step 1: Wash and crush milk thistle, Agave sphenanthera leaves, pineapple and longan to obtain an initial mixed plant; the mass ratio of Agave sphenanthera leaves, milk thistle, pineapple and longan is 1: (0.1-0.3): (0.5-1): (0.2-0.4); Step 2: initially mixing the plants with water and treating them at an ultrasonic power of 1000-1500 W for 5-10 minutes to obtain an ultrasonically treated product; Step 3: treating the ultrasonically treated product under microwave conditions of 500-600 W and 60-80° C. for 1-3 min to obtain a microwave-treated product; Step 4: Adding acetic acid bacteria, Bacillus subtilis, and white rot fungi to the microwave-treated product, and fermenting for 7-10 days to obtain a fermentation mixture; Step 5: centrifuging the fermentation mixture, collecting the supernatant, and obtaining the composite extract of Ampelopsis grossedentata leaves.

[0006] Under the treatment of ultrasound, microwave and microbial fermentation, the synergistic effect of Agave sphenanthera leaves, milk thistle, pineapple and longan not only greatly increased the content of flavonoids, but also significantly enhanced the antioxidant and anti-inflammatory properties of the composite extract.

[0007] The leaves of Agave glabra, with its rich flavonoids such as D-flavonoids, myricetin and quercetin, have become the core component of this synergistic system. These flavonoids play a vital role in anti-oxidation, anti-inflammatory and immune regulation. When Agave glabra leaves are combined with the other three plants, the flavonoids can synergize with the active ingredients in other plants to produce more significant biological effects.

[0008] Silymarin, which is unique to milk thistle, can scavenge free radicals. Under the fermentation of specially selected microorganisms, the active ingredients in milk thistle can be better released, complementing the flavonoids in plants such as Agave sphenanthera leaves, and together improving the overall antioxidant properties.

[0009] Pineapple is rich in nutrients such as vitamin C, minerals and dietary fiber. Under the action of microbial fermentation, some components in pineapple are transformed to produce metabolites with anti-inflammatory effects. They work together with the anti-inflammatory properties of Agave leaves and milk thistle to help reduce inflammatory responses.

[0010] The glucose, sucrose, protein, and various vitamins and minerals in the longan pulp can be better absorbed and utilized through microbial fermentation, and work together with the active ingredients of plants such as the leaves of Agave sphenanthera to promote repair.

[0011] During the fermentation process, Acetobacter, Bacillus subtilis and white rot fungi can not only destroy the plant cell walls and release more active ingredients, but also change the structure of flavonoids through metabolism and enhance their biological activity. At the same time, the metabolites produced by microorganisms, such as vitamins and amino acids, work together with the active ingredients in plants to enhance the overall antioxidant and anti-inflammatory properties.

[0012] Preferably, the mass of the acetic bacteria is 0.1-0.5% of the total mass of the Agave ulmoides leaves, milk thistle, pineapple and longan, the mass of the Bacillus subtilis is 0.1-0.5% of the total mass of the Agave ulmoides leaves, milk thistle, pineapple and longan, and the mass of the white rot fungus is 0.05-0.2% of the total mass of the Agave ulmoides leaves, milk thistle, pineapple and longan.

[0013] Preferably, the mass ratio of the Acetobacter, Bacillus subtilis and white rot fungi is 1:(0.8-1.2):(0.2-0.4).

[0014] By adopting the above technical scheme, the dosage relationship of Acetobacter, Bacillus subtilis and white rot fungi with Agave sphenanthera leaves, milk thistle, pineapple and longan is further limited, which can not only maximize the release of flavonoids in plants, but also promote the production of more metabolites with antioxidant and anti-inflammatory effects. This synergistic effect not only improves the biological activity of the extract, but also realizes the efficient use of resources, providing strong support for the development of efficient and safe natural medicines and health foods.

[0015] Preferably, the mass ratio of the initial mixed plants to water is 1:(5-10).

[0016] Preferably, the fermentation in step 4 is carried out at 25-30°C.

[0017] Preferably, in step 1, the milk thistle, Ampelopsis macrophylla leaves, pineapple and longan are crushed to 500-800 μm.

[0018] By adopting the above technical solution, raw materials such as milk thistle, Agave sphenanthera, pineapple, and longan are crushed to 500-800 μm, which helps to fully release the flavonoid compounds in the extraction process and increase the flavonoid content. At the same time, the particle size of 500-800 μm is limited to increase the specific surface area of ​​the raw materials as much as possible, which is conducive to the effective dissolution and stable existence of antioxidant and anti-inflammatory components.

[0019] In a second aspect, the present application provides a composite extract of Ampelopsis grossedentata leaves.

[0020] By adopting the above technical scheme, with the synergistic cooperation of Agave sphenanthera leaves, milk thistle, pineapple and longan, Agave sphenanthera leaves are taken as the core to fully extract the rich flavonoid compounds contained therein, and combined with the other three plants, the flavonoids and other active ingredients are coordinated with each other to obtain a composite extract with excellent antioxidant and anti-inflammatory effects and significantly improved flavonoid content.

[0021] In a third aspect, the present application provides an application of a composite extract of Ampelopsis grossedentata leaves in biomedicine and health food.

[0022] The composite extract provided in this application has significant application advantages in biomedicine and health foods. Its rich flavonoids, such as D-flavonoids, myricetin, etc., show strong antioxidant and anti-inflammatory properties, which help to scavenge free radicals, slow down cell aging, and reduce inflammatory responses. In the field of biomedicine, the extract can be used to develop anti-inflammatory and anti-aging drugs. In health foods, it can enhance immunity, promote health, and provide consumers with natural and healthy nutritional choices. These applications not only meet the market demand for high-quality health products, but also show the broad prospects of the composite extract of Agave sphenanthera.

[0023] In summary, this application has the following beneficial effects: 1. As the core ingredients of the composite extract, the leaves of Agave sphenanthera, milk thistle, pineapple and longan are used together with ultrasound, microwave and microbial fermentation technology to fully extract and release flavonoids, and make these active ingredients more stable in the composite extract, showing stronger biological activity, thus providing high-quality raw materials for the fields of biomedicine and health food.

[0024] 2. The leaves of Agave sphenanthera, milk thistle, pineapple and longan work together in the composite extract to exert good antioxidant and anti-inflammatory effects. The flavonoids of Agave sphenanthera leaves, silymarin of milk thistle, anti-inflammatory metabolites of pineapple and nutrients in longan, under the action of microbial fermentation, jointly enhance the antioxidant and anti-inflammatory properties of the composite extract. This characteristic makes the composite extract perform well in scavenging free radicals, slowing down cell aging and reducing inflammatory responses, providing strong support for the development of anti-inflammatory and anti-aging drugs.

[0025] 3. The compound extract has significant application advantages in the field of biomedicine and health food. Its rich flavonoids and antioxidant and anti-inflammatory properties make the extract have broad market prospects in the development of anti-inflammatory drugs, anti-aging products and health foods that enhance immunity. At the same time, as a natural and healthy nutritional choice, the compound extract also meets consumers' demand for high-quality health products. As people's awareness of health continues to improve, the application prospects of the compound extract of Agave sphenanthera will be broader, bringing new development opportunities to the biomedicine and health food industries. DETAILED DESCRIPTION

[0026] The present application is further described in detail below with reference to the embodiments.

[0027] The raw materials used in the following examples and comparative examples are all commercially available products.

[0028] The following are some sources of raw materials: Acetobacter was purchased from Ningbo Mingzhou Biotechnology Co., Ltd., BMZ135334.

[0029] Bacillus subtilis was purchased from Ningbo Mingzhou Biotechnology Co., Ltd., BMZ135814.

[0030] White rot fungi were purchased from Ningbo Mingzhou Biotechnology Co., Ltd., B82046.

[0031] Example 1

[0032] A method for preparing a composite extract of Ampelopsis grossedentata leaves comprises the following steps: Step 1: Prepare the ingredients according to the mass ratio of Agave sphenanthera leaves, milk thistle, pineapple and longan of 1:0.2:0.8:0.3.

[0033] In this embodiment, the amount of Ampelopsis grossedentata leaves is 10 kg, the amount of Silybum marianum is 2 kg, the amount of pineapple is 8 kg, and the amount of longan is 3 kg.

[0034] Wash milk thistle, Agave oleracea leaves, pineapple, and longan with clean water.

[0035] Then, milk thistle, Ampelopsis grandis leaves, pineapple and longan were put into a grinder and ground to 600 μm to obtain an initial mixed plant.

[0036] Step 2: Prepare materials according to the mass ratio of initial mixed plants to water of 1:8, and mix the initial mixed plants with water.

[0037] Then, the mixture was ultrasonically treated at an ultrasonic power of 1200 W for 8 min to obtain an ultrasonically treated product.

[0038] Step 3: The ultrasonically treated product was subjected to microwave treatment at a microwave power of 550 W and a temperature of 70° C. for 2 min to obtain a microwave-treated product.

[0039] Step 4: Prepare the materials according to the mass of Acetobacter being 0.3% of the total mass of Agave ulmoides leaves, milk thistle, pineapple and longan, the mass of Bacillus subtilis being 0.3% of the total mass of Agave ulmoides leaves, milk thistle, pineapple and longan, and the mass of white rot fungi being 0.09% of the total mass of Agave ulmoides leaves, milk thistle, pineapple and longan.

[0040] In this embodiment, the amount of Acetobacter is 0.069 kg, the amount of Bacillus subtilis is 0.069 kg, and the amount of white rot fungi is 0.0207 kg.

[0041] Acetobacter, Bacillus subtilis and white rot fungi were added into the microwave treated material, and fermented at 28°C for 8 days to obtain a fermentation mixture.

[0042] Step 5: centrifuge the fermentation mixture, collect the supernatant, and obtain the composite extract of Ampelopsis grossedentata leaves.

[0043] This embodiment also provides an application of a composite extract of Ampelopsis grossedentata leaves in biomedicine and health food. The composite extract of Ampelopsis grossedentata leaves can be directly added to health food and biomedicine and mixed until uniform.

[0044] Example 2

[0045] A method for preparing a composite extract of Ampelopsis grossedentata leaves, which is different from that of Example 1 in that some parameters are different, specifically comprises the following steps: Step 1: Prepare the ingredients according to the mass ratio of Agave sphenanthera leaves, milk thistle, pineapple and longan of 1:0.1:0.5:0.2.

[0046] In this embodiment, the amount of Ampelopsis grossedentata leaves is 10 kg, the amount of Silybum marianum is 1 kg, the amount of pineapple is 5 kg, and the amount of longan is 2 kg.

[0047] Wash milk thistle, Agave oleracea leaves, pineapple, and longan with clean water.

[0048] Then, milk thistle, Ampelopsis grandis leaves, pineapple and longan were put into a grinder and ground into 500 μm to obtain an initial mixed plant.

[0049] Step 2: Prepare materials according to the mass ratio of initial mixed plants to water of 1:5, and mix the initial mixed plants with water.

[0050] Then, the mixture was ultrasonically treated at an ultrasonic power of 1000 W for 10 min to obtain an ultrasonically treated product.

[0051] Step 3: The ultrasonically treated product was subjected to microwave treatment at a microwave power of 500 W and a temperature of 80° C. for 1 min to obtain a microwave-treated product.

[0052] Step 4: prepare the materials according to the mass of Acetobacter being 0.1% of the total mass of Agave ulmoides leaves, milk thistle, pineapple and longan, the mass of Bacillus subtilis being 0.1% of the total mass of Agave ulmoides leaves, milk thistle, pineapple and longan, and the mass of white rot fungi being 0.05% of the total mass of Agave ulmoides leaves, milk thistle, pineapple and longan.

[0053] In this embodiment, the amount of Acetobacter is 0.018 kg, the amount of Bacillus subtilis is 0.018 kg, and the amount of white rot fungi is 0.009 kg.

[0054] Acetobacter, Bacillus subtilis and white rot fungi were added into the microwave treated material, and fermented at 25° C. for 10 days to obtain a fermentation mixture.

[0055] Step 5: centrifuge the fermentation mixture, collect the supernatant, and obtain the composite extract of Ampelopsis grossedentata leaves.

[0056] Example 3

[0057] A method for preparing a composite extract of Ampelopsis grossedentata leaves, which is different from that of Example 1 in that some parameters are different, specifically comprises the following steps: Step 1: Prepare the ingredients according to the mass ratio of Agave sphenanthera leaves, milk thistle, pineapple and longan of 1:0.3:1:0.4.

[0058] In this embodiment, the amount of Ampelopsis grossedentata leaves is 10 kg, the amount of Silybum marianum is 3 kg, the amount of pineapple is 10 kg, and the amount of longan is 4 kg.

[0059] Wash milk thistle, Agave oleracea leaves, pineapple, and longan with clean water.

[0060] Then, milk thistle, Ampelopsis grandis leaves, pineapple and longan were put into a grinder and ground to 800 μm to obtain an initial mixed plant.

[0061] Step 2: Prepare materials according to the mass ratio of initial mixed plants to water of 1:10, and mix the initial mixed plants with water.

[0062] Then, the mixture was ultrasonically treated at an ultrasonic power of 1500 W for 5 min to obtain an ultrasonic-treated product.

[0063] Step 3: The ultrasonically treated product was subjected to microwave treatment at a microwave power of 600 W and a temperature of 60° C. for 3 min to obtain a microwave-treated product.

[0064] Step 4: prepare the materials according to the mass of Acetobacter being 0.5% of the total mass of Agave ulmoides leaves, milk thistle, pineapple and longan, the mass of Bacillus subtilis being 0.5% of the total mass of Agave ulmoides leaves, milk thistle, pineapple and longan, and the mass of white rot fungi being 0.2% of the total mass of Agave ulmoides leaves, milk thistle, pineapple and longan.

[0065] In this embodiment, the amount of Acetobacter is 0.135 kg, the amount of Bacillus subtilis is 0.135 kg, and the amount of white rot fungi is 0.054 kg.

[0066] Acetobacter, Bacillus subtilis and white rot fungi were added into the microwave treated material, and fermented at 30°C for 7 days to obtain a fermentation mixture.

[0067] Step 5: centrifuge the fermentation mixture, collect the supernatant, and obtain the composite extract of Ampelopsis grossedentata leaves.

[0068] Example 4

[0069] A method for preparing a composite extract of Ampelopsis grossedentata leaves is different from that of Example 1 in that the mass ratio of acetic acid bacteria, Bacillus subtilis, and white rot fungi is 1:0.8:0.4, that is, acetic acid bacteria is 0.069 kg, Bacillus subtilis is 0.0552 kg, and white rot fungi is 0.0276 kg.

[0070] Example 5

[0071] A method for preparing a composite extract of Ampelopsis grossedentata leaves is different from that of Example 1 in that the mass ratio of acetic acid bacteria, Bacillus subtilis, and white rot fungi is 1:1.2:0.2, that is, acetic acid bacteria is 0.069 kg, Bacillus subtilis is 0.0828 kg, and white rot fungi is 0.0138 kg.

[0072] Comparative Example 1 A method for preparing a composite extract of Ampelopsis grossedentata leaves is different from that in Example 1 in that milk thistle is replaced by kudzu root.

[0073] Comparative Example 2 A method for preparing a composite extract of Ampelopsis grossedentata leaves, which is different from that of Example 1 in that pineapple is replaced by litchi.

[0074] Comparative Example 3 A method for preparing a composite extract of Ampelopsis grossedentata leaves, which is different from that of Example 1 in that longan is replaced by grape.

[0075] Comparative Example 4 A method for preparing a composite extract of Ampelopsis grossedentata leaves is different from that of Example 1 in that milk thistle, pineapple and longan are replaced with Ampelopsis grossedentata leaves.

[0076] Comparative Example 5 A method for preparing a composite extract of Ampelopsis grossedentata leaves is different from that of Example 1 in that the mass ratio of Ampelopsis grossedentata leaves, milk thistle, pineapple and longan is 1:0.5:0.1:0.6.

[0077] In this embodiment, the amount of Ampelopsis grossedentata leaves is 10 kg, the amount of Silybum marianum is 5 kg, the amount of pineapple is 1 kg, and the amount of longan is 6 kg.

[0078] Comparative Example 6 A method for preparing a composite extract of Agave sphenanthera leaves, which is different from that of Example 1 in that the mass of Acetobacter is 0.03% of the total mass of Agave sphenanthera leaves, milk thistle, pineapple and longan, the mass of Bacillus subtilis is 0.03% of the total mass of Agave sphenanthera leaves, milk thistle, pineapple and longan, and the mass of white rot fungi is 0.63% of the total mass of Agave sphenanthera leaves, milk thistle, pineapple and longan.

[0079] That is, Acetobacter is 0.0069kg, Bacillus subtilis is 0.0069kg, and white rot fungi is 0.1449kg.

[0080] 1. Total flavonoids content: Accurately weigh 20 mg of rutin reference substance dried to constant weight at 105°C, dissolve it in 60% ethanol, and dilute to 100 mL as the reference substance stock solution. According to the NaNO2-Al(NO3)3-NaOH system complex chemical method, with the reagent blank as the reference, draw a rutin standard curve at 510 nm, and the linear equation is: A=0.0109C-0.012 (C: concentration, mg·mL -1 ; A: absorbance value), R=0.9997.

[0081] 1.0 mL of the composite extracts of Ampelopsis grossedentata leaves of Examples 1-5 and Comparative Examples 1-6 were taken respectively, diluted to 10 mL, and the absorbance was measured at 510 nm according to the working curve method to calculate the total flavonoid yield. The total flavonoid yield is recorded in Table 1.

[0082]

[0083] Where: C is the mass concentration of flavonoids in the extract, mg·mL -1 ; V is the total volume of the extract, mL; M is the dry basis mass of the substance to be tested, g.

[0084] 2. Antioxidant performance: DPPH free radical inhibition rate test Weigh 0.5 g of the composite extracts of the leaves of Ampelopsis grossedentata of Examples 1-5 and Comparative Examples 1-6, respectively, dissolve them in pure water, and transfer them to a 100 mL volumetric flask to make up to volume, and prepare a 5.00 × 10 -3 g / mL of sample solution.

[0085] Pipette 3 mL of the sample solution to be tested into a 10 mL volumetric flask, then add 3 mL of a 2×10 -4 g / mL DPPH solution. Cover the stopper, shake well, react for 30 minutes, and measure the absorbance A at 517nm i ; Determine the absorbance A of 3mL sample solution and 3mL ethanol mixture j ; The concentration of 3mL was determined to be 2×10 -4 The absorbance A0 of a DPPH solution of 0.05 g / mL mixed with 3 mL of pure water.

[0086] According to the formula P = [1-(A i -A j ) / A0]×100%, and the measured absorbance was substituted into the inhibitory rate of the test solution on DPPH· free radicals.

[0087] The inhibition rates are recorded in Table 1.

[0088] 3. Anti-inflammatory properties: RAW264.7 macrophages (1×10 4 / well) were cultured in 96-well plates. 1 mL of DMEM medium containing 10% fetal bovine serum was added to each well and cultured in a 5% CO2 incubator (37°C) for 4 h. The cells were then randomly divided into blank group (cells + culture medium), LPS group (1 μg / mL LPS + cells), and experimental group (complex extract of Agave sphenanthera leaves + 1 μg / mL LPS + cells), with 3 replicates in each group.

[0089] The composite extract of Ampelopsis grossedentata leaves used in the experimental group was derived from the composite extract of Ampelopsis grossedentata leaves of Examples 1-5 and Comparative Examples 1-6.

[0090] The mass concentration of RAW264.7 macrophages treated with the composite extract of Ampelopsis grossedentata leaves in the experimental group was 50 μg / mL, and LPS with a final mass concentration of 1 μg / mL was added to stimulate the cells. After 24 hours, the supernatant was used to detect the expression of inflammatory factor TNF-α by ELISA kit, and the results were recorded in Table 1.

[0091] Table 1

[0092] In the anti-inflammatory performance test, the TNF-α level in the LPS group was significantly higher than that in the blank group, indicating that the model was successfully established. Compared with the LPS group, the TNF-α levels of the composite extracts of the leaves of Ampelopsis grossedentata in Examples 1-5 and Comparative Examples 1-6 all tended to decrease, indicating that the composite extracts of the leaves of Ampelopsis grossedentata in Examples 1-5 and Comparative Examples 1-6 had different degrees of anti-inflammatory effects.

[0093] Comparative Examples 1-3 are based on Example 1, and any of milk thistle, pineapple, and longan are replaced with other raw materials; Comparative Example 4 is based on Example 1, and only the leaves of Agave sphenanthera are left; Comparative Example 5 is based on Example 1, and the mass ratio of Agave sphenanthera leaves, milk thistle, pineapple, and longan is changed; Comparative Example 6 is based on Example 1, and the mass matching relationship of Acetobacter, Bacillus subtilis, and white rot fungi is changed. That is, Comparative Examples 1-6 are based on Example 1, and the combination of Agave sphenanthera leaves, milk thistle, pineapple, and longan or Acetobacter, Bacillus subtilis, and white rot fungi is damaged to varying degrees.

[0094] According to the comparison of the test data in Table 1, the composite extracts of the leaves of Ampelopsis grossedentata in Examples 1-5 contain higher amounts of flavonoids than those of Comparative Examples 1-6, and also have more significant inhibitory effects on DPPH free radicals, and lower TNF-α levels. In other words, the composite extracts of the leaves of Ampelopsis grossedentata in Examples 1-5 have more significant antioxidant and anti-inflammatory effects than those of Comparative Examples 1-6.

[0095] It is said that the leaves of Agave serrata, milk thistle, pineapple and longan can effectively improve the extraction efficiency of flavonoids and obtain a composite extract with more significant anti-inflammatory and antioxidant properties under the combination of specific dosages, ultrasound, microwave, selected acetic acid bacteria, Bacillus subtilis and white rot fungi. Any degree of damage to the technical solution will affect the synergistic coordination contained therein and fail to achieve significant results.

[0096] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for preparing a composite extract of Ampelopsis grossedentata leaves, characterized in that: The following steps are involved: Step 1: Wash and crush milk thistle, Agave sphenanthera leaves, pineapple and longan to obtain an initial mixed plant; the mass ratio of Agave sphenanthera leaves, milk thistle, pineapple and longan is 1: (0.1-0.3): (0.5-1): (0.2-0.4); Step 2: initially mixing the plants with water and treating them at an ultrasonic power of 1000-1500 W for 5-10 minutes to obtain an ultrasonically treated product; Step 3: treating the ultrasonically treated product under microwave conditions of 500-600 W and 60-80° C. for 1-3 min to obtain a microwave-treated product; Step 4: Adding acetic acid bacteria, Bacillus subtilis, and white rot fungi to the microwave-treated product, and fermenting for 7-10 days to obtain a fermentation mixture; Step 5: centrifuging the fermentation mixture, collecting the supernatant, and obtaining a composite extract of Ampelopsis grossedentata leaves.

2. The method for preparing the composite extract of Ampelopsis grossedentata leaves according to claim 1, characterized in that: The mass of the acetic acid bacteria is 0.1-0.5% of the total mass of the Agave ulmoides leaves, milk thistle, pineapple and longan, the mass of the Bacillus subtilis is 0.1-0.5% of the total mass of the Agave ulmoides leaves, milk thistle, pineapple and longan, and the mass of the white rot fungus is 0.05-0.2% of the total mass of the Agave ulmoides leaves, milk thistle, pineapple and longan.

3. The method for preparing the composite extract of Ampelopsis grossedentata leaves according to claim 2, characterized in that: The mass ratio of the acetic acid bacteria, the Bacillus subtilis and the white rot fungus is 1: (0.8-1.2): (0.2-0.4).

4. The method for preparing the composite extract of Ampelopsis grossedentata leaves according to claim 1, characterized in that: The mass ratio of the initial mixed plants to water is 1:(5-10).

5. The method for preparing the composite extract of Ampelopsis grossedentata leaves according to claim 1, characterized in that: The step 4 is fermented at 25-30°C.

6. The method for preparing the composite extract of Ampelopsis grossedentata leaves according to claim 1, characterized in that: In the step 1, milk thistle, Ampelopsis macrophylla leaves, pineapple and longan are crushed into 500-800 μm.

7. A composite extract of Ampelopsis grossedentata leaves prepared by the method for preparing the composite extract of Ampelopsis grossedentata leaves according to any one of claims 1 to 6.

8. Use of the composite extract of Ampelopsis grossedentata leaves according to claim 7 in biomedicine and health food.

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