Lotus leaf acidic homogeneous polysaccharide as well as preparation method and application thereof

Abstract

The invention discloses a lotus leaf acidic homogeneous polysaccharide as well as a preparation method and application thereof, and belongs to the technical field of biological medicines. The polysaccharide is LLP-W with the molecular weight of 7.032 kDa or LLP-0.2 with the molecular weight of 18.774 kDa, the monosaccharide composition and molar ratio of the polysaccharide are clear, and the purity reaches 99% or above. The preparation method comprises the following steps: carrying out ethanol degreasing, hot water extraction and ethanol precipitation on lotus leaves to obtain a crude product, and then purifying through anion exchange column chromatography and gel column chromatography in sequence. The polysaccharide can effectively improve liver lipid deposition, and the mechanism of the polysaccharide relates to activation of GPR41 receptors through intestinal flora metabolites, so that lipid metabolism related signal channels are regulated and controlled, and fat accumulation is inhibited. The polysaccharide provided by the invention is clear in structure and definite in activity, and can be used for preparing medicines or health-care foods for preventing or treating obesity, non-alcoholic fatty liver and other metabolic diseases.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology, specifically relating to the isolation, identification and pharmaceutical application of natural active polysaccharides, and particularly to a lotus leaf acidic homogeneous polysaccharide, its preparation method and its application in improving liver lipid deposition. Background Technology

[0002] Lotus leaf, a traditional Chinese plant used for both food and medicine, is the dried leaf of the lotus (Nelumbo nucifera), a member of the Nymphaeaceae family. Its application has a long history, with ancient medical texts recording its various effects, including clearing heat and dampness, strengthening the spleen and raising yang, and dispersing blood stasis and stopping bleeding. It is commonly used to treat edema, summer heat, thirst, and other symptoms. With the deepening of modern phytochemistry and pharmacology research, the value of lotus leaf has transcended traditional experience, attracting widespread attention from researchers. Studies have shown that lotus leaf contains a rich variety of natural active ingredients, mainly including polysaccharides, flavonoids, alkaloids, and volatile oils. These components collectively constitute the material basis of the pharmacological effects of lotus leaf. Among them, lotus leaf polysaccharides, as an important class of biomolecules, have gradually become a hot topic in the field of natural product research and development due to their natural origin, high biosafety, and broad physiological regulatory potential.

[0003] Numerous in vitro and in vivo experiments have revealed the multifaceted biological activities of lotus leaf polysaccharides. Regarding the regulation of glucose metabolism, studies have found that it can help lower blood glucose levels by influencing related enzyme activity or the insulin signaling pathway. In terms of lipid metabolism regulation, evidence suggests that lotus leaf polysaccharides help reduce serum total cholesterol and triglyceride levels in experimental animals, demonstrating its potential for lipid-lowering. Furthermore, its antioxidant capacity has been confirmed, enabling it to scavenge free radicals and reduce oxidative stress damage to body tissues. These research findings provide a scientific basis for the application of lotus leaf polysaccharides in functional foods and health products.

[0004] However, despite the aforementioned understanding of the macroscopic bioactivity of lotus leaf polysaccharides, current research still faces several key weaknesses and unresolved issues. On the one hand, existing reports largely focus on the activity evaluation of crude lotus leaf polysaccharides or preliminarily purified fractions, while research on homogeneous polysaccharide monomers that exert specific functions is relatively scarce. The bioactivity of polysaccharides is closely related to their precise molecular structure, including molecular weight, monosaccharide composition, glycosidic bond linkage, and spatial conformation. The lack of structurally well-defined, high-purity homogeneous polysaccharide samples severely restricts in-depth analysis of the structure-activity relationship of lotus leaf polysaccharides and poses challenges to their quality control and standardized production. On the other hand, regarding whether lotus leaf polysaccharides can directly and effectively inhibit abnormal fat deposition in cells or the body, particularly their specific intervention effects on diseases closely related to lipid metabolism disorders such as non-alcoholic fatty liver disease, the direct evidence provided by existing literature is insufficient. Furthermore, the related molecular pathways and cellular signaling mechanisms remain shrouded in mystery and have not been clearly elucidated.

[0005] Specifically, the pathological process of lipid deposition involves complex metabolic network regulation, including multiple stages such as adipocyte differentiation, lipid synthesis, degradation, transport, and inflammatory responses. Exploring a natural product capable of multi-target, gentle intervention in this process is of great significance for the prevention and treatment of metabolic diseases such as obesity and fatty liver. Therefore, the targeted isolation and preparation of a structurally defined, homogeneous polysaccharide component from lotus leaves, a traditional resource, and the systematic and in-depth elucidation of its precise effects and underlying mechanisms in inhibiting lipid deposition, will not only fill existing knowledge gaps and deepen our understanding of the pharmacodynamic material basis of lotus leaves, but also provide new, scientifically supported candidate molecules for the development of related health products, possessing clear theoretical value and application prospects. Summary of the Invention

[0006] Technical Problem Solved: To address the issue that existing research on lotus leaf polysaccharides primarily focuses on crude extracts or mixtures of components, lacking systematic separation and identification of structurally clear, high-purity, homogeneous polysaccharide monomers, and that their effectiveness in inhibiting lipid deposition and related specific molecular mechanisms remains unclear, this invention provides a homogeneous acidic lotus leaf polysaccharide, its preparation method, and its applications. This method can accurately obtain lotus leaf polysaccharide monomers with a purity exceeding 99% and clearly defined molecular weight and monosaccharide composition. Furthermore, it demonstrates that these monomers can effectively improve liver lipid deposition and inhibit adipocyte differentiation and lipid accumulation through pathways such as activation of the GPR41 receptor by intestinal flora metabolites. This provides a definitive material basis and mechanism of action for developing products to prevent and treat obesity and related metabolic diseases.

[0007] Technical solution: A homogeneous acidic polysaccharide derived from lotus leaves, having a molecular weight of 7.032 kDa or 18.774 kDa, wherein the polysaccharide is composed of four monosaccharides: galactose, arabinose, rhamnose, and galacturonic acid; wherein, in the polysaccharide with a molecular weight of 7.032 kDa, the molar ratio of the four monosaccharides is galactose:arabinose:rhamnose:galacturonic acid = 0.356:0.233:0.151:0.118; and in the polysaccharide with a molecular weight of 18.774 kDa, the molar ratio of the four monosaccharides is galactose:galacturonic acid:rhamnose:arabinose = 0.378:0.221:0.149:0.129.

[0008] Its purity is no less than 99%.

[0009] A method for preparing the aforementioned acidic homogeneous polysaccharide from lotus leaves includes the following steps: a) taking dried lotus leaves, defatting them by reflux with 50%-95% ethanol, then performing thermal extraction with water at 60℃-100℃, combining the extracts, concentrating them, and adding ethanol to a final concentration of 75%-85% for precipitation, collecting the precipitate and drying it to obtain crude lotus leaf polysaccharide; b) dissolving the crude lotus leaf polysaccharide obtained in step a) in water, loading it onto a DEAE-Cellulose anion exchange cellulose chromatography column, eluting with distilled water, collecting the water-eluted fraction, dialysis, concentration, and drying to obtain the lotus leaf water-washed component polysaccharide; c) dissolving the lotus leaf water-washed component polysaccharide obtained in step b) in a solution with a concentration of 0.05-0.25... The sample was loaded into a gel chromatography column in a mol / L NaCl solution and eluted with the same concentration of NaCl solution. The elution process was monitored using a differential detector, and the single symmetrical peak component corresponding to the target molecular weight was collected. After dialysis and drying, the lotus leaf acidic homogeneous polysaccharide was obtained.

[0010] In step a), the ethanol reflux defatting time is 1-18 hours, and the hot extraction time is 1-8 hours.

[0011] In step a), the ethanol is allowed to stand for 4-48 hours after precipitation.

[0012] In step c), the gel chromatography column is a high-efficiency gel permeation chromatography column.

[0013] The above-mentioned lotus leaf acidic homogeneous polysaccharide is used in the preparation of products for improving liver lipid deposition.

[0014] The aforementioned improvements in liver lipid deposition include reducing liver triglyceride and total cholesterol levels.

[0015] The above products are medications used for the prevention or treatment of non-alcoholic fatty liver disease.

[0016] The above products are food or health food products with lipid-lowering functions.

[0017] Beneficial Effects: This invention successfully isolated two structurally well-defined, high-purity, acidic homogeneous polysaccharides, LLP-W and LLP-0.2, from lotus leaves. This method effectively removed impurities such as proteins and nucleic acids, achieving a final product purity of over 99%. Furthermore, the precise molecular weights, monosaccharide composition ratios, and main glycosidic bond linkages of both polysaccharides were clearly defined for the first time at the structural chemistry level, filling a gap in the field's understanding of the fine structure of homogeneous lotus leaf polysaccharides.

[0018] Based on a clear understanding of their structures, this invention further reveals the significant effects and unique mechanisms by which these two polysaccharides improve lipid metabolism disorders. In vitro cell experiments confirmed that both LLP-W and LLP-0.2 effectively reduced oleic acid-induced lipid deposition in HepG2 cells, decreasing intracellular triglyceride and total cholesterol levels. More importantly, in an in vivo mouse model of non-alcoholic fatty liver disease induced by a high-fat diet, intervention with these two polysaccharides not only inhibited excessive weight gain and hepatic lipid accumulation but also improved glucose tolerance and insulin resistance, demonstrating a dual regulatory effect on glucose and lipid metabolism. Further mechanistic studies revealed that the benefits of lotus leaf polysaccharides partly stem from the active substances produced after metabolism by gut microbiota. These substances specifically activate the GPR41 receptor, thereby regulating the expression of downstream key genes such as PPARα and ATGL, promoting lipid breakdown, inhibiting synthesis, and alleviating hepatic inflammatory responses.

[0019] While LLP-W and LLP-0.2 share the same core efficacy, their subtle structural differences lead to complementarity in their specific mechanisms of action. For example, they each focus on improving certain metabolic indicators or regulating specific gene expression profiles. This characteristic means that using them alone or in combination may provide more precise intervention strategies for different aspects of metabolic disorders. This invention not only verifies the direct application value of lotus leaf polysaccharides in inhibiting fat deposition and improving fatty liver, but also reveals a mechanism of action through the gut microbiota-GPR41 axis. This provides a scientific basis and technical pathway for developing functional food or drug lead compounds for the prevention or treatment of obesity, non-alcoholic fatty liver disease, and related metabolic syndromes, with broad market application prospects. Attached Figure Description

[0020] Figure 1 Extraction and purification of lotus leaf polysaccharides. (A) Chromatogram of crude LLP eluted by a DEAE gel column. (B) Determination of the average relative molecular mass of LLP-W by high-performance gel permeation chromatography (HPGPC). (C) Determination of the average relative molecular mass of LLP-0.2 by high-performance gel permeation chromatography (HPGPC). (D) Fourier transform infrared spectrum of LLP-W. (E) Fourier transform infrared spectrum of LLP-0.2.

[0021] Figure 2 Monosaccharide composition and methylation analysis of LLP-W and LLP-0.2.

[0022] Figure 3 This study presents the results of multidimensional experiments on OA-induced HepG2 cells treated with LLP-W and LLP-0.2, and on high-fat diet (HFD) treated with LLP-W and LLP-0.2. (A) Results of OA induction and Nile Red staining. (B) Oil Red quantification. (C) Fluorescence intensity. (D) Changes in cellular TC and TG content. (E) Relative mRNA expression levels of inflammation-related genes (IL1) in different treatment groups. (F) Relative mRNA expression levels of lipid metabolism-related genes (CD36, ACOX1, ACC1, FASN, PPARγ, PPARα) in different treatment groups.

[0023] Figure 4 This is a comprehensive experimental result of the effects of LLP-W and LLP-0.2 interventions in a mouse model of non-alcoholic fatty liver disease (NAFLD). (A) Changes in body weight and liver function in different treatment groups in the NAFLD model. (B) Results of glucose metabolism in mice detected by OGTT and ITT. (C) Changes in serum and liver TC and TG levels. (D) Relative mRNA expression levels of related genes (TGF-β1, GPR41, ATGL, ACC1, Perilip, PPARα, CEBPa, PParg) in different treatment groups.

[0024] Figure 5 This is a composite experimental result of the effects of LLP-W and LLP-0.2 interventions in a pseudo-germ-free mouse (ABX) model. (A) Changes in body weight and liver weight in different treatment groups in the ABX-treated mouse model. (B) HE-stained liver and intestinal sections. (C) Changes in serum and liver TC and TG levels. (D) Relative mRNA expression levels of inflammatory factors (TNF-α, IL-1β, IL-6) and related inflammatory genes (TNF-α, IL-1β, IL-6) and lipid metabolism genes (FATP2, CD36, FABP1, FABP4, MTTP, ApoB) in different treatment groups. Detailed Implementation

[0025] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading this invention, any modifications of the invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0026] Example 1

[0027] 1. Preparation and Identification of Homogeneous Polysaccharides from Lotus Leaves

[0028] a) Take 2 kg of dried lotus leaves and grind them into powder. Add 10 L of water and extract three times under boiling conditions. Then add 4 times the volume of ethanol for alcohol precipitation (v / v, which is equivalent to 4 times the volume of the concentrated liquid). After 24 hours, filter, collect the precipitate and dry it to remove residual ethanol.

[0029] b) Take 10g of the prepared crude polysaccharide, add 100mL of distilled water to dissolve, and perform polar separation using a DEAE-Cellulose 52 anion exchange column. Elute with 0.2M NaCl solution at a flow rate of 2mL / min. Detect the sugar content using the sulfuric acid-phenol method and monitor at 490nm using an ELISA reader to obtain the elution curve. Figure 1 A) Collect the sugar-containing solution, dry it, dialyze it with an 8000 Da dialysis bag for 24 hours, and then freeze-dry it to obtain lotus leaf W component polysaccharide and lotus leaf 0.2 component polysaccharide.

[0030] 2. Purity and molecular weight determination

[0031] High-performance liquid chromatography-gel chromatography (HPGPC) was used: the column was BRT105-104-102, the detector was a differential detector, the mobile phase was 0.05 mol / L sodium chloride solution, the column temperature was 40℃, the flow rate was 0.6 mL / min, and the injection volume was 20 μL.

[0032] Accurately weigh the sample and standards. Prepare a 5 mg / mL solution of the sample, centrifuge at 12000 rpm for 10 min, filter the supernatant through a 0.22 μm microporous membrane, and then transfer the sample to a 1.8 mL vial with an injection volume of 20 μL. The mobile phase of the instrument is 0.05 M sodium chloride solution, and the flow rate is 0.6 mL / min. Use dextran with different relative molecular masses (Mw1152, 11600, 23800, 48600, 80900, 148000, 273000, 409800) as standards to construct a standard curve and determine the purity and relative molecular mass of the polysaccharides.

[0033] Based on the standard curve, a calculation formula was derived to calculate the molecular weight of each sample. Figure 1 High-performance liquid chromatography-gel chromatography (HPGPC) was obtained for LLP-W and LLP-0.2. The graphs showed a single symmetrical peak, indicating that they are homogeneous polysaccharides. The relative molecular weight of LLP-W was calculated to be 7.032 kDa, and the relative molecular weight of LLP-0.2 was 18.774 kDa.

[0034] 3. Monosaccharide composition analysis

[0035] Accurately weigh 0.2 mg of LLP-W and 0.2 mg of LLP-W, then add 2 mL of trifluoroacetic acid. Hydrolyze in a metal bath at 120 °C for 2 h, then evaporate by rotary evaporation until no sour smell remains. Add sodium borohydride as a reducing agent and reduce overnight. Add acetic acid to neutralize excess sodium borohydride. Evaporate using a rotary evaporator until a viscous consistency is reached. Add 3-5 mL of methanol solution, repeating 3 times. Then add 1 mL of acetic anhydride and react at 101 °C for 1 h. Stop the reaction by adding water and extract with dichloromethane. Wash 3 times with 10 mL of distilled water each time. Finally, collect the dichloromethane layer, dry it with anhydrous sodium sulfate, and analyze it using a Shimadzu GC-MS-QP2010.

[0036] GC-MS conditions: RXI-5 SILMS column, 30×0.25×0.25 mm; temperature program: initial temperature 120℃, ramped at 3℃ / min to 250℃ / min; hold for 5 min; injector temperature 250℃, detector temperature 250℃ / min; carrier gas: helium, flow rate 1 mL / min. Standards were selected in the following order: fucose, galactose, rhamnose, arabinose, glucosamine, galactopyranose, glucose, acetylglucosamine, xylose, mannose, and fructose.

[0037] Detection results: GC-MS analysis of the LLP-W mainly showed four peaks, which, after comparison with standard monosaccharides, were confirmed to be galactose, arabinose, rhamnose, and galacturonic acid. Figure 2 The GC-MS results of LLP-0.2 mainly showed four peaks, which, after comparison with standard monosaccharides, were identified as galactose, galacturonic acid, rhamnose, and arabinose. Figure 2 ).

[0038] 4. Methylation analysis

[0039] Weigh 10 mg each of LLP-W and LLP-0.2, add 2 mL of dimethyl sulfoxide, then add NaOH powder. Wrap the test tube with aluminum foil and operate in the dark. Then add iodomethane reagent and react under ice bath conditions. Finally, add water to terminate the reaction, dialyze and freeze dry. Take 1-2 mg of the fully methylated polysaccharide, add 2 mL of 2M trifluoroacetic acid and hydrolyze for 2 h. Evaporate to dryness until no sour taste remains, then add an appropriate amount of sodium borohydride for reduction overnight, evaporate to a viscous state, then add 2-5 mL of methanol, and repeat evaporation three times. Then add acetic anhydride, acetylate, and neutralize with water. Finally, analyze using gas chromatography-mass spectrometry (Shimadzu GCMS-QP2010).

[0040] GC-MS conditions: RXI-5 SILMS column 30×0.25×0.25; temperature program conditions: initial temperature 120℃, increase to 280℃ / min at 4℃ / min; hold for 5min; injection port temperature 250℃, detector temperature 250℃ / min, carrier gas helium, flow rate 1mL / min.

[0041] Methylation analysis revealed that LLP-W contains six glycosidic bonds: Araf-(1→,→2,4)-Rhap-(1→), Glcp-(1→,→4)-Galp-(1→,→6)-Galp-(1→,→3,6)-Galp-(1→). LLP-0.2 contains eight glycosidic bonds: Araf-(1→,→3,4)-Rhap-(1→,→5)-Araf-(1→,→4)-Galp-(1→,→3,4)-Galp-(1→,→4,6)-Glcp-(1→,→3,6)-Galp-(1→,→3,4,6)-Glcp-(1→).

[0042] Evaluation of the molecular mechanism of lipid-lowering effect of lotus leaf polysaccharide

[0043] A stable in vitro NAFLD model was established by co-incubating HepG2 cells with 0.25 mM oleic acid (OA) for 24 hours. The model group showed greater lipid deposition compared to other groups, and LLP-W and LLP-0.2 showed an effect in reducing lipid deposition. Nile red staining also confirmed the lipid-reducing effect of LLP-W and LLP-0.2, consistent with OA staining results. The HFD group had significantly higher levels of specific cholesterol forms than the NC group; LLP intervention reduced this indicator (improved lipid metabolism), while triglyceride (TG) levels significantly increased. LLP intervention reduced this indicator (reduced lipid accumulation). High-fat diets (HFD) induce lipid accumulation and tissue / molecular abnormalities; LLP intervention can improve these metabolic disorders. HFD promotes the expression of lipid metabolism-related genes and induces an increase in the inflammatory gene IL1; LLP-W and LLP-0.2 treatments reversed these changes—both inhibiting the abnormal activation of lipid metabolism-related genes and reducing the inflammatory response.

[0044] Evaluation of the activity of lotus leaf polysaccharides in improving obesity

[0045] A high-fat diet successfully induced non-alcoholic fatty liver disease (NAFLD) in mice (weight gain, liver enlargement, and fat accumulation), and lotus leaf polysaccharide intervention significantly improved these pathological changes associated with fatty liver. LLP-W and LLP-0.2 were administered to mice via gavage at doses of 100 mg / kg and 150 mg / kg body weight daily, respectively, for 8 consecutive weeks. Gavage administration of lotus leaf polysaccharide improved glucose and insulin resistance levels in mice, with the LLP-0.2 group showing better glucose and insulin resistance compared to the other two groups. A high-fat diet induced lipid metabolism disorders in serum and liver, while lotus leaf polysaccharide intervention improved peripheral (serum) and hepatic lipid abnormalities. AST and ALT are hallmark indicators of liver injury; higher values ​​indicate more severe liver damage. These indicators suggest that HFD-induced metabolic disorders are accompanied by liver damage, and LLP intervention simultaneously improved lipid metabolism, glucose metabolism, and liver function. A high-fat diet can suppress the expression of related genes, while LLP-W and LLP-0.2 interventions can reverse the downregulation of these genes, suggesting that these two interventions can improve metabolic disorders caused by a high-fat diet.

[0046] Research on the regulation of gut microbiota by lotus leaf polysaccharides

[0047] In ABX mice fed a high-fat diet, LLP-w and LLP-0.2 effectively inhibited weight gain, reduced weight gain / accumulation in the liver and adipose tissue, and improved obesity-related expression induced by the high-fat diet. A high-fat diet leads to hepatic steatosis and intestinal morphological damage in mice; LLP-w and LLP-0.2 interventions improved the pathological damage of these tissues. LLP-w and LLP-0.2 interventions also increased serum lipids, increased hepatic lipid accumulation, and liver damage in mice; while LLP-w and LLP-0.2 interventions reduced blood lipid levels, decreased hepatic lipid deposition, and improved liver damage. Furthermore, a high-fat diet not only leads to high expression of pro-inflammatory genes and disordered lipid metabolism-related genes (promoting lipid accumulation), but also improves fatty liver by downregulating pro-inflammatory genes and regulating lipid metabolism genes (reducing lipid intake / accumulation and promoting lipid transport); it also leads to increased hepatic lipid synthesis and decreased lipid breakdown, while disrupting adipocyte function; while lotus leaf polysaccharide interventions improve lipid metabolism disorders in fatty liver by downregulating lipid synthesis genes, upregulating lipid breakdown genes, and regulating adipocyte / metabolic genes.

[0048] The above examples are merely illustrative of the technical concept and features of this invention, intended to enable those skilled in the art to understand the content of this invention and implement it accordingly, and should not be construed as limiting the scope of protection of this invention. All equivalent transformations or modifications made in accordance with the spirit and essence of this invention should be included within the scope of protection of this invention.

Claims

1. A homogeneous acidic polysaccharide from lotus leaves, characterized in that, Its molecular weight is 7.032 kDa or 18.774 kDa, and the polysaccharide is composed of four monosaccharides: galactose, arabinose, rhamnose, and galacturonic acid. Specifically, in the polysaccharide with a molecular weight of 7.032 kDa, the molar ratio of the four monosaccharides is galactose:arabinose:rhamnose:galacturonic acid = 0.356:0.233:0.151:0.118; in the polysaccharide with a molecular weight of 18.774 kDa, the molar ratio of the four monosaccharides is galactose:galacturonic acid:rhamnose:arabinose = 0.378:0.221:0.149:0.

129.

2. The lotus leaf acidic homogeneous polysaccharide according to claim 1, characterized in that, Its purity is no less than 99%.

3. A method for preparing the lotus leaf acidic homogeneous polysaccharide according to claim 1 or 2, characterized in that, Includes the following steps: a) Take dried lotus leaves, defatt them by reflux with 50%-95% ethanol, and then perform hot extraction with water at 60℃-100℃. Combine the extracts, concentrate them, and add ethanol to a final concentration of 75%-85% for precipitation. Collect the precipitate and dry it to obtain crude lotus leaf polysaccharide; b) Dissolve the crude lotus leaf polysaccharide obtained in step a) in water, load it onto a DEAE-Cellulose anion exchange cellulose chromatography column, elute with distilled water, collect the water-eluted fraction, and obtain the lotus leaf water-washed polysaccharide fraction by dialysis, concentration and drying. c) Dissolve the lotus leaf water-washed polysaccharide obtained in step b) in a NaCl solution with a concentration of 0.05-0.25 mol / L, load the sample onto a gel chromatography column, and elute with NaCl solution of the same concentration. Monitor the elution process using a differential detector, collect the single symmetrical peak component corresponding to the target molecular weight, and obtain the lotus leaf acidic homogeneous polysaccharide after dialysis and drying.

4. The method according to claim 3, characterized in that, In step a), the ethanol reflux defatting time is 1-18 hours, and the hot extraction time is 1-8 hours.

5. The method according to claim 3, characterized in that, In step a), the ethanol is allowed to stand for 4-48 hours after precipitation.

6. The method according to claim 3, characterized in that, In step c), the gel chromatography column is a high-efficiency gel permeation chromatography column.

7. The use of the lotus leaf acidic homogeneous polysaccharide according to claim 1 or 2 in the preparation of a product for improving liver lipid deposition.

8. The application according to claim 7, characterized in that, The improvement in liver lipid deposition includes reducing liver triglyceride and total cholesterol levels.

9. The application according to claim 7, characterized in that, The product is a medication used to prevent or treat non-alcoholic fatty liver disease.

10. The application according to claim 7, characterized in that, The product is a food or health food with lipid-lowering function.

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