Camellia oleifera shell polyphenol extract and preparation method and application thereof

Abstract

The present invention belongs to the technical field of plant active ingredient extraction and application, and specifically relates to a tea oil shell polyphenol extract and its preparation method and application. The present invention makes full use of tea oil processing byproduct tea oil shell as raw material, under mild conditions, fully destroys the tea oil shell by grinding, extracts in combination with microwave-assisted extraction, and then purifies with macroporous resin and nanofilters. Under the premise of maintaining a high yield, the activity of the obtained tea oil shell polyphenol extract is significantly improved, and it has a high inhibitory effect on amylase. In addition, the present invention can improve the comprehensive utilization rate of waste, reduce production costs, increase economic benefits, and reduce environmental pollution problems caused by discarded tea oil shells, and has positive economic benefits and social significance.

Description

Technical Field

[0001] This invention belongs to the technical field of plant active ingredient extraction and application. More specifically, it relates to a camellia oleifera fruit shell polyphenol extract, its preparation method, and its application. Background Technology

[0002] Camellia oleifera fruit shells, also known as camellia seed shells, account for more than 60% of the weight of a single camellia fruit. They are a byproduct of camellia oil processing, with approximately three million tons produced annually. In actual production, most camellia oleifera fruit shells are discarded or incinerated, failing to achieve effective utilization. However, current research has found that camellia oleifera fruit shells are rich in active substances such as saponins, tannins, polyphenols, and polysaccharides, possessing various antioxidant, antibacterial, anti-inflammatory, and anti-cancer physiological activities. For example, phenolic substances such as proanthocyanidins and hydrolyzed tannins in camellia oleifera fruit shells have been proven to have a good inhibitory effect on intestinal amylase and α-glucosidase, helping to achieve slow digestion and absorption of starch, maintaining postprandial blood glucose homeostasis, and preventing various diet-related chronic diseases. Furthermore, as a natural product, the polyphenols in camellia oleifera fruit shells align with people's pursuit of natural, healthy, safe, and non-toxic medicines.

[0003] To improve the extraction efficiency of polyphenols from camellia oleifera fruit shells, existing technologies commonly use microwave, ultrasonic, and ultra-high pressure extraction techniques with auxiliary solvent extraction. For example, Chinese patent application CN103030710A discloses a method for the resource utilization of camellia oleifera fruit shells. This method involves microwave treatment of the fruit shells, followed by high-temperature, long-duration, and repeated alcohol and water extractions to obtain the active ingredients polyphenols and polysaccharides. The residue is then treated with additives and subjected to high-temperature pyrolysis to prepare bio-oil and biochar products. Although this method yields a high product rate, the high temperature, long duration, and repeated extraction operations can easily cause changes in the active ingredients in the camellia oleifera fruit shells, especially unstable active ingredients such as polyphenols, leading to a decrease in the activity of the extract. Therefore, there is an urgent need for a camellia oleifera fruit shell extraction method that improves the bioactivity of the extract while maintaining a high extraction rate. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects and shortcomings of the existing camellia fruit shell polyphenol extraction methods, which require high temperature, long time and multiple extractions, resulting in reduced activity of the extract. The present invention provides a method for preparing camellia fruit shell polyphenol extract, which is carried out under mild conditions and can quickly and with high yield obtain camellia fruit shell polyphenol extract with high activity.

[0005] The purpose of this invention is to provide a camellia fruit shell polyphenol extract obtained by the preparation method described above.

[0006] Another object of the present invention is to provide the application of the camellia oleifera fruit shell polyphenol extract.

[0007] The above-mentioned objective of this invention is achieved through the following technical solution:

[0008] A method for preparing a polyphenol extract from Camellia oleifera fruit shell specifically includes the following steps:

[0009] S1. Dry the camellia fruit shell and crush it to obtain coarse powder of camellia fruit shell;

[0010] S2. Mix and grind the coarse powder of camellia fruit shell obtained in step S1 with the composite solid additive to obtain fine powder of camellia fruit shell.

[0011] S3. Add ethanol solution to the fine powder of Camellia oleifera fruit shell obtained in step S2, and extract with microwave-assisted extraction at 210-350W for 60-90 seconds.

[0012] S4. Centrifuge the extract, collect the supernatant, remove the ethanol, adjust the pH to 4-5, and add water until the volume is the same as the volume after adding the ethanol solution in step S3.

[0013] S5. Dilute the extract obtained in S4 and load it onto a macroporous resin column. After adsorption is complete, rinse with water to remove impurities, then elute with ethanol solution, collect the eluent, and remove the ethanol.

[0014] S6. Filter the eluent obtained in step S5 using a nanofiltration membrane and collect the filtrate to obtain the final product.

[0015] Furthermore, in step S1, the drying process is carried out until the moisture content is 5-8%.

[0016] Preferably, in step S1, the pulverized material is passed through a 40-80 mesh sieve.

[0017] Preferably, in step S1, the drying is hot air drying or heat pump drying, and the temperature is 40-60°C.

[0018] Furthermore, in step S2, the composite solid additive is sodium carbonate, hydroxypropyl-β-cyclodextrin, and microcrystalline cellulose.

[0019] Further, in step S2, the mass ratio of sodium carbonate, hydroxypropyl-β-cyclodextrin (HP-β-CD), and microcrystalline cellulose (MCC) is 1–4:0.5–1:1–2.

[0020] Further, in step S2, the amount of the solid additive added is 1% to 4% of the mass of the coarse camellia fruit shell powder. Preferably, the amount of the solid additive added is 2% to 4% of the mass of the coarse camellia fruit shell powder.

[0021] Preferably, in step S2, the grinding is a planetary ball mill, a vibratory ball mill, or a stirring ball mill.

[0022] Furthermore, in step S2, the grinding time is 5 to 20 minutes.

[0023] Furthermore, in step S3, the volume concentration of the ethanol solution is 30% to 50%.

[0024] Furthermore, in step S3, the mass-to-volume ratio of the camellia fruit shell powder to the ethanol solution is 1:5 to 20 g / ml.

[0025] Preferably, in step S5, the dilution factor is 2 to 4 times.

[0026] Further, in step S5, the macroporous resin is HP20, LSA-21, or AB-8.

[0027] Furthermore, in step S5, the volume concentrations of the ethanol solution used for elution are 20%, 50%, 70%, and 90%, respectively.

[0028] Preferably, in step S5, the flow rate for loading the sample is 1-2 mL / min, and the flow rate for elution is 1-2 mL / min.

[0029] Furthermore, in step S6, the molecular weight cutoff of the nanofiltration membrane is 500–3000 Da.

[0030] In addition, the present invention also provides a camellia fruit shell polyphenol extract obtained by the preparation method described above.

[0031] Studies have found that the Camellia oleifera fruit shell polyphenol extract prepared by this invention has a significant inhibitory effect on amylase. Therefore, this invention also claims protection for the use of the Camellia oleifera fruit shell polyphenol extract in the preparation of amylase inhibitors. Preferably, the amylase is α-amylase or α-glucosidase.

[0032] The present invention has the following beneficial effects:

[0033] This invention fully utilizes camellia fruit shells, a byproduct of camellia oil processing, as raw material. Under mild conditions, the camellia fruit shells are thoroughly broken down by grinding, and then extracted using microwave-assisted extraction. While maintaining a high yield, this significantly improves the activity of the obtained camellia fruit shell polyphenol extract, exhibiting a high inhibitory effect on amylase. Furthermore, this invention can improve the comprehensive utilization rate of waste, reduce production costs, increase economic benefits, and reduce environmental pollution caused by waste camellia fruit shells, thus possessing positive economic and social significance. Detailed Implementation

[0034] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0035] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0036] Example 1: A method for preparing a polyphenol extract from camellia oleifera fruit shell.

[0037] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0038] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0039] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 2% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 2:1:2). The mixture is then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0040] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 1 min.

[0041] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0042] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0043] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0044] Example 2: A method for preparing a polyphenol extract from camellia oleifera fruit shell.

[0045] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0046] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0047] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 3% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 2:1:2). The mixture is then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0048] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 1 min.

[0049] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0050] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0051] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0052] Example 3: A method for preparing a polyphenol extract from camellia oleifera fruit shell.

[0053] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0054] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0055] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 4% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 2:1:2). The mixture is then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0056] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 1 min.

[0057] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0058] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0059] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0060] Example 4: A method for preparing a polyphenol extract from camellia oleifera fruit shell.

[0061] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0062] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0063] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 3% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 2:1:1) and then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0064] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 1 min.

[0065] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0066] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0067] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0068] Example 5: A method for preparing a polyphenol extract from camellia oleifera fruit shell.

[0069] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0070] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0071] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 3% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 4:1:1) and then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0072] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 1 min.

[0073] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0074] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0075] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0076] Example 6: A method for preparing a polyphenol extract from camellia oleifera fruit shell.

[0077] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0078] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0079] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 3% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 2:1:2) and then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0080] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 210W and extract for 1 min.

[0081] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0082] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0083] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0084] Example 7: A method for preparing a polyphenol extract from camellia oleifera fruit shell.

[0085] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0086] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0087] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 3% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 2:1:2). The mixture is then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0088] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 350W and extract for 1 min.

[0089] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0090] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0091] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0092] Example 8: A method for preparing a polyphenol extract from camellia oleifera fruit shell.

[0093] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0094] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0095] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 3% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 2:1:2). The mixture is then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0096] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shells, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 1.5min.

[0097] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0098] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0099] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0100] Comparative Example 1: A method for preparing a polyphenol extract from camellia oleifera fruit shell

[0101] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0102] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0103] S2. Place the coarse powder of camellia fruit shell obtained in step S1 into a planetary ball mill and grind for 10 minutes to obtain fine powder of camellia fruit shell.

[0104] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 1 min.

[0105] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0106] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0107] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0108] Comparative Example 2: A method for preparing a polyphenol extract from Camellia oleifera fruit shell

[0109] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0110] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0111] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 1% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 2:1:2). The mixture is then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0112] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 1 min.

[0113] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0114] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0115] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0116] Comparative Example 3: A method for preparing a polyphenol extract from Camellia oleifera fruit shell

[0117] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0118] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0119] S2. Mix the coarse powder of camellia fruit shell obtained in step S1 with sodium carbonate at 3% of the mass of the coarse powder of camellia fruit shell and put it into a planetary ball mill and grind for 10 minutes to obtain fine powder of camellia fruit shell.

[0120] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 1 min.

[0121] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0122] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0123] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0124] Comparative Example 4: A method for preparing a polyphenol extract from camellia oleifera fruit shell

[0125] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0126] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0127] S2. Mix the coarse Camellia oleifera fruit shell powder obtained in step S1 with 3% (by weight) of hydroxypropyl-β-cyclodextrin and place it in a planetary ball mill. Grind for 10 minutes to obtain fine Camellia oleifera fruit shell powder.

[0128] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 1 min.

[0129] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0130] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0131] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0132] Comparative Example 5: A method for preparing a polyphenol extract from the shell of Camellia oleifera.

[0133] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0134] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0135] S2. Mix the coarse powder of camellia fruit shell obtained in step S1 with 3% of the mass of microcrystalline cellulose of the coarse powder of camellia fruit shell and put it into a planetary ball mill and grind for 10 minutes to obtain fine powder of camellia fruit shell.

[0136] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 1 min.

[0137] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0138] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0139] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0140] Comparative Example 6: A method for preparing a polyphenol extract from camellia oleifera fruit shell

[0141] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0142] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0143] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 3% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 2:1:2). The mixture is then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0144] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of Camellia oleifera fruit shell, and extract at 70℃ for 50 min.

[0145] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0146] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0147] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0148] Comparative Example 7: A method for preparing a polyphenol extract from camellia oleifera fruit shell

[0149] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0150] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0151] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 3% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 2:1:2). The mixture is then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0152] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 420W and extract for 1 min.

[0153] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0154] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0155] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0156] Comparative Example 8: A method for preparing a polyphenol extract from camellia oleifera fruit shell.

[0157] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0158] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0159] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 3% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 2:1:2). The mixture is then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0160] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shells, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 0.5min.

[0161] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0162] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0163] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0164] Comparative Example 9: A method for preparing a polyphenol extract from camellia oleifera fruit shell

[0165] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0166] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0167] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 3% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 2:1:2). The mixture is then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0168] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 2 minutes.

[0169] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0170] S5. Pretreated LSA-21 macroporous resin was packed into a glass chromatography column. The extract obtained in S4 was diluted 4 times and loaded onto the column at a flow rate of 2 mL / min. After adsorption was complete, some impurities were removed by elution with 1 BV of distilled water. Then, 1 BV of 20%, 50%, 70% and 90% ethanol solutions were used for elution at a flow rate of 2 mL / min. The eluents were combined and the ethanol was removed by rotary evaporation.

[0171] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0172] Comparative Example 10: A method for preparing a polyphenol extract from camellia oleifera fruit shell

[0173] The preparation method of the camellia oleifera fruit shell polyphenol extract specifically includes the following steps:

[0174] S1. Dry the camellia fruit shells to a moisture content of 5%, crush them, and pass them through a 60-mesh sieve to obtain coarse camellia fruit shell powder.

[0175] S2. The coarse powder of camellia fruit shell obtained in step S1 is mixed with 3% of the mass of the coarse powder of camellia fruit shell and a composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose in a ratio of 2:1:2). The mixture is then placed in a planetary ball mill and ground for 10 minutes to obtain fine powder of camellia fruit shell.

[0176] S3. Add a 50% ethanol solution with a material-to-liquid ratio of 1:20 (g / ml) to the fine powder of camellia fruit shell, and use microwave-assisted extraction method. Set the microwave instrument power to 280W and extract for 2 minutes.

[0177] S4. Centrifuge the extract at 5000r / min for 10min, collect the supernatant, remove ethanol by rotary evaporation, adjust the pH to 5, and add distilled water until the volume is the same as the volume after adding ethanol solution in step S3.

[0178] S5. Dilute the extract obtained in S4 until its polyphenol concentration is consistent with that of the extract obtained in S4 in Example 2.

[0179] S6. Filter the eluent obtained in S5 using a nanofiltration membrane with a molecular weight cutoff of 3000 Da, collect the filtrate, and obtain the camellia oleifera fruit shell polyphenol extract.

[0180] Effects of different extraction conditions on extract yield and extract activity in experimental examples

[0181] The extraction yield, α-amylase inhibition rate, and α-glucosidase inhibition rate of the camellia oleifera fruit shell polyphenol extracts obtained in the examples and comparative examples were determined using the following methods:

[0182] 1. Determination of extract yield:

[0183] Polyphenol content was determined using the Folin-Ciocalteu method. 10 mg of gallic acid was accurately weighed, dissolved in water, and transferred to a 100 mL amber volumetric flask. The solution was then diluted to volume to obtain a 0.1 mg / mL stock solution. 0, 1, 2, 3, 4, and 5 mL of the stock solution were respectively transferred to 10 mL amber volumetric flasks and diluted to volume to obtain gallic acid standard solutions with concentrations of 0.01, 0.02, 0.03, 0.04, and 0.05 mg / mL. 1 mL of each standard solution was added to 2 mL of (0.1 N) Folin-Ciocalteu reagent, mixed, and allowed to stand for 5 min. Then, 4 mL of 7.5% Na₂CO₃ was added, and the solution was diluted to 10 mL. The solution was then incubated at room temperature in the dark for 1 h, and the absorbance was measured at 765 nm. A standard curve was plotted with the concentration c of the gallic acid standard sample as the x-axis and the absorbance as the y-axis, yielding the regression equation: y = 15.05x - 0.007(R²). 2 =0.999).

[0184] Make up the volume of the camellia fruit shell polyphenol extract solution to a certain volume, pipette 1 mL into a colorimetric tube, repeat the above operation, and calculate the polyphenol content in the sample according to the following equation. The result is expressed as mg / g.

[0185]

[0186] Where c represents the measured polyphenol concentration, mg / mL; V is the volume of the camellia fruit shell polyphenol extract solution, mL; and m is the dry weight of the camellia fruit shell, g.

[0187] 2. Determination of α-amylase inhibition rate:

[0188] 0.2 mL of Camellia oleifera fruit shell polyphenol extract solution and 0.2 mL of 0.4 mg / mL α-amylase solution (prepared with a pH 6.8 buffer) were placed in a colorimetric tube and incubated in a 37°C water bath for 10 min. Then, 0.2 mL of 1% starch solution was added, and the reaction was allowed to proceed for another 10 min. Finally, 0.2 mL of DNS reagent was added, and the mixture was heated in a boiling water bath for 8 min. After cooling, the volume was adjusted to 10 mL, and the absorbance was measured at 540 nm. The inhibition rate was calculated using the following formula:

[0189]

[0190] Among them, A i A0 represents the absorbance of the camellia oleifera fruit shell polyphenol extract solution, while A0 represents the absorbance measured using an equal volume of phosphate buffer solution instead of the camellia oleifera fruit shell polyphenol extract solution. t The absorbance values ​​measured in the bottom tube group of the Camellia oleifera fruit shell polyphenol extract solution were obtained by replacing the α-amylase solution with phosphate buffer solution.

[0191] 3. Determination of α-glucosidase inhibition rate:

[0192] Add 0.1 mL of Camellia oleifera fruit shell extract solution and 0.2 mL of 0.2 U / mL α-glucosidase (prepared with pH 6.8 buffer) to a test tube containing 0.9 mL of phosphate buffer. Incubate at 37°C for 10 min. Add 0.2 mL of 2.5 mmol pNPG solution and react for 30 min. Then add 0.8 mL of 0.2 mol / L Na₂CO₃. After standing for 15 min, measure the absorbance at 405 nm. The inhibition rate is calculated using the following formula:

[0193]

[0194] Among them, A i A0 represents the absorbance of the camellia oleifera fruit shell polyphenol extract solution, while A0 represents the absorbance measured using an equal volume of phosphate buffer solution instead of the camellia oleifera fruit shell polyphenol extract solution. t The absorbance values ​​measured in the bottom tube group of the Camellia oleifera fruit shell polyphenol extract solution were obtained by replacing the α-amylase solution with phosphate buffer solution.

[0195] The effects of solid additive type and dosage on extraction yield and extract activity are shown in Table 1.

[0196] Table 1. Effect of solid adjuvant dosage on extraction yield and extract activity.

[0197]

[0198] As shown in Table 1, pretreatment of the raw materials with 2%–4% of composite solid additives, 3% sodium carbonate, 3% hydroxypropyl-β-cyclodextrin, and 3% microcrystalline cellulose can effectively increase the extraction yield of polyphenols from Camellia oleifera fruit shells, thereby enhancing their inhibitory ability on α-amylase and α-glucosidase.

[0199] The extract yield and activity of the fruit shell treated with 1% compound solid adjuvant did not change significantly. When the amount of compound solid adjuvant added increased from 1% to 4%, the extract yield and activity showed an increasing trend. When the amount reached 3%, the extract yield and activity reached their maximum and then remained basically unchanged.

[0200] When the amount of solid additives added was 3%, the polyphenol extraction yield and the ability to inhibit the two enzymes showed a consistent trend: composite solid additive (composed of sodium carbonate, hydroxypropyl-β-cyclodextrin, and microcrystalline cellulose in different proportions) > hydroxypropyl-β-cyclodextrin > sodium carbonate > microcrystalline cellulose. Sodium carbonate can react with polyphenols rich in phenolic hydroxyl groups to form salts, and the activities of α-amylase and α-glucosidase are easily affected by the phenolic hydroxyl groups of polyphenols in the environment. Therefore, a certain amount of solid alkali additive is beneficial to the dissolution of polyphenols and can improve the ability of polyphenol extracts to inhibit α-amylase and α-glucosidase. Hydroxypropyl-β-cyclodextrin and microcrystalline cellulose can solubilize polyphenols and increase the extraction yield. The extract obtained from camellia fruit shells treated with the composite solid additive, which is a mixture of these three solid additives in a certain proportion, has a higher polyphenol extraction yield and stronger inhibition of α-amylase and α-glucosidase, which may be due to a synergistic relationship between the three substances.

[0201] The effects of microwave extraction conditions on the extraction yield and the activity of the extract are shown in Table 2.

[0202] Table 2 Effects of microwave extraction conditions on extract yield and extract activity.

[0203]

[0204] As shown in Table 2, the polyphenol extraction yield from Camellia oleifera fruit shells obtained by microwave extraction at 210W power for 1 minute is close to that obtained by extraction at 70℃ for 50 minutes. This indicates that microwave extraction can effectively shorten the extraction time and yield polyphenols close to those obtained by traditional extraction. Further analysis of α-amylase and α-glucosidase inhibition rates revealed significant differences in the inhibitory activities of the polyphenol extracts from Camellia oleifera fruit shells obtained by the two methods: the longer extraction time and more thorough extraction, coupled with the prolonged thermal environment, easily decomposes large polyphenol molecules into smaller phenolic compounds, transforming strong inhibitory phenolic compounds into weakly inhibitory ones. In contrast, microwave extraction may contain higher levels of substances that inhibit α-amylase and α-glucosidase activity. Therefore, while the polyphenol content is similar between the extraction and microwave methods, the enzyme inhibitory activity is lower.

[0205] Furthermore, within a certain timeframe, as microwave power (210W–350W) increases, the system heats up rapidly, and the solid-liquid diffusion rate also accelerates, leading to intensified cell rupture and a gradual increase in the extraction yield of fruit shell polyphenols, reaching its maximum at around 350W. However, when the microwave power increases to 420W, it may cause excessively high local temperatures, easily decomposing polyphenolic substances. The higher extraction yield of Camellia oleifera fruit shell polyphenol extract did not exhibit the highest inhibitory activity against α-amylase and α-glucosidase; instead, the extract obtained at 280W power showed stronger activity. This may be because, during the increase in microwave power from 280W to 350W, more phenolic substances dissolved from the fruit shell, but the thermal effect of high power also led to the transformation of strongly inhibitory phenolic compounds into weakly inhibitory ones.

[0206] With increasing microwave time (0.5 min–2 min), the extraction yield of fruit shell polyphenols gradually increased, and the inhibition rates against α-amylase and α-glucosidase gradually increased, reaching a maximum at 1 min. When the microwave time was further extended, both the extraction yield and inhibitory activity of fruit shell polyphenols decreased. At microwave treatment times of 0.5 min and 2 min, the extraction yield of fruit shell polyphenols was lower than that obtained by immersion extraction, but the enzyme inhibitory activities were comparable.

[0207] The effects of macroporous resin purification on the extraction yield and extract activity are shown in Table 3.

[0208] Table 3. Effects of macroporous resin purification on extract yield and extract activity.

[0209]

[0210] The results in Table 3 show that purification with macroporous resin can effectively remove large molecules such as polysaccharides and proteins from the camellia oleifera fruit shell polyphenol extract obtained in S4, effectively avoiding the clogging of the nanofiltration membrane, thereby enriching more active polyphenols and significantly improving enzyme inhibitory activity.

[0211] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a polyphenol extract from camellia oleifera shell, characterized in that: The specific steps include: S1. Drying and crushing the camellia oleifera shell to obtain camellia oleifera shell coarse powder; S2, mixing and grinding the coarse powder of camellia oleifera shell obtained in step S1 with the composite solid additive to obtain fine powder of camellia oleifera shell; S3, adding ethanol solution to the fine powder of camellia oleifera shell obtained in step S2, and performing microwave-assisted extraction at 210-350 W for 60 s-90 s; S4, centrifuging the extract, collecting the supernatant, removing ethanol, adjusting the pH to 4-5, and adding water to a volume consistent with the volume after adding the ethanol solution in step S3; S5, diluting the extract obtained in S4 and loading it onto a macroporous resin column, after adsorption is completed, washing with water to remove impurities, then eluting with an ethanol solution, collecting the eluate, and removing ethanol; S6, filtering the eluate obtained in step S5 with a nanofiltration membrane, and collecting the filtrate to obtain; The composite solid auxiliary agent is sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose; In step S3, the volume concentration of the ethanol solution is 30% to 50%; In step S5, the volume concentration of the ethanol solution is 20%, 50%, 70% and 90% respectively; In step S5, the macroporous resin is LSA-21; The mass ratio of the sodium carbonate, hydroxypropyl-β-cyclodextrin and microcrystalline cellulose is 1-4:0.5-1:1-2; In step S2, the total added amount of the composite solid additive is 1% to 4% of the mass of the camellia oleifera shell coarse powder.

2. The preparation method according to claim 1, characterized in that: In step S6, the molecular weight cutoff of the nanofiltration membrane is 500-3000 Da.

3. The camellia oleifera shell polyphenol extract obtained by the preparation method according to claim 1 or 2.

4. Use of the camellia oleifera shell polyphenol extract according to claim 3 in the preparation of amylase inhibitors.

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