An acidic polysaccharide from Polygonatum odoratum, its preparation method and application

Abstract

This invention belongs to the field of biomedical technology and relates to an acidic polysaccharide from Polygonatum sibiricum, its preparation method, and its application. The molecular weight, determined by multi-angle laser light scattering, is 35.0–45.0 kDa. It is composed of Gal, GalA, Rha, Man, and Ara in a mass ratio of 50–60:15–25:10–15:5–10:1–4. The monosaccharide linkage types are mainly →4)-β-Galp-(1→, →4)-β-Manp-(1→, →2)-α-Rhap-(1→, →4)-α-GalpA-6-O-Me-(1→, →4)-2-O-acetyl-β-Manp-(1→) and T-α-GalpA-(1→). This invention extracts a new acidic polysaccharide from Polygonatum sibiricum processed through nine steaming and nine sun-drying. This acidic polysaccharide exhibits strong hypoglycemic activity and low toxicity.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology and relates to an acidic polysaccharide of Polygonatum odoratum, its preparation method and application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Polygonatum sibiricum, also known as earth spirit mushroom, sun grass, chicken head ginseng, etc., is the dried tuber of a perennial herbaceous plant belonging to the genus Polygonatum in the family Liliaceae. The 2020 edition of the *Pharmacopoeia of the People's Republic of China* includes three species of Polygonatum (Polygonatum sibiricum Red, Polygonatum kingianum Coll. et Hemsl, and Polygonatum cyrtonema Hua). Polygonatum is mild in nature, sweet in taste, and beneficial to the spleen, lung, and kidney meridians, possessing the effects of tonifying the kidneys and replenishing essence, nourishing yin and moistening dryness. As a precious "food and medicine homology" traditional Chinese medicine, Polygonatum contains many chemical components, mainly including polysaccharides, saponins, and flavonoids. Among these, polysaccharides are the main components of Polygonatum, playing a variety of pharmacological roles. Summary of the Invention

[0004] Because raw Polygonatum sibiricum is irritating to the throat, it is usually steamed and dried nine times before use. "Nine steaming and nine drying" is a common method of processing medicinal materials, which can effectively remove the irritation of raw Polygonatum sibiricum and increase its efficacy. This invention studies the polysaccharide components of Polygonatum sibiricum processed through "nine steaming and nine drying" and isolates a new acidic polysaccharide. This polysaccharide is different from all currently known Polygonatum sibiricum polysaccharides, and the obtained polysaccharide component has strong hypoglycemic activity. Therefore, this invention is proposed.

[0005] Based on the above research results, this invention provides an acidic polysaccharide from Polygonatum odoratum, its preparation method, and its application. The technical solution is as follows:

[0006] On one hand, a polysaccharide of Polygonatum odoratum, with a molecular weight of 35.0–45.0 kDa determined by multi-angle laser light scattering, is composed of D-galactose (Gal), galacturonic acid (GalA), L-rhamnose (Rha), D-mannose (Man), and L-arabinose (Ara). The molar ratio of Gal, GalA, Rha, Man, and Ara is 50–60:15–25:10–15:5–10:1–4. The monosaccharide linkage types are mainly →4)-β-Galp-(1→, →4)-β-Manp-(1→, →2)-α-Rhap-(1→, →4)-α-GalpA-6-O-Me-(1→, →4)-2-O-acetyl-β-Manp-(1→) and T-α-GalpA-(1→).

[0007] Furthermore, the chemical structure of the Polygonatum odoratum acidic polysaccharide contains →4)-β-D-Galp-(1→4)-β-D-Galp-(1→ linker fragment, →4)-β-D-Galp-(1→4)-β-D-Manp-(1→ linker fragment, →2)-α-L-Rhap-(1→4)-β-D-Galp-(1→ linker fragment, →4)-α-D-GalpA-6-O-Me-(1→2)-α-L-Rhap-(1→ linker fragment, T-α-D-GalpA-(1→4)-α-D-GalpA-6-O-Me-(1→ linker fragment, →4)-β-D-Manp-(1→4)-2-O-acetyl-β-D-Manp-(1→ linker fragment).

[0008] On the other hand, a method for preparing the above-mentioned acidic polysaccharide of Polygonatum sibiricum involves steaming and drying raw Polygonatum sibiricum nine times to obtain cooked Polygonatum sibiricum, extracting the cooked Polygonatum sibiricum by water reflux, precipitating the water extract with alcohol, removing lipids and proteins to obtain a Polygonatum sibiricum polysaccharide extract, eluting the Polygonatum sibiricum polysaccharide extract using DEAE-52 ion exchange column chromatography, using water and a 0.1-0.3M NaCl aqueous solution sequentially during the elution process, and purifying the eluted portion with the 0.1-0.3M NaCl aqueous solution to obtain the acidic polysaccharide of Polygonatum sibiricum.

[0009] Thirdly, the application of the above-mentioned Polygonatum odoratum acidic polysaccharide in the preparation of hypoglycemic products.

[0010] The beneficial effects of this invention are as follows:

[0011] This invention discloses a novel acidic polysaccharide PRP-9A isolated and purified from Polygonatum sibiricum processed by "nine steaming and nine sun-drying". This acidic polysaccharide has good hypoglycemic activity and low toxicity, showing good development prospects. Attached Figure Description

[0012] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0013] Figure 1 The infrared spectrum of PRP-9A, an acidic polysaccharide extracted from Polygonatum sibiricum, is shown in the embodiments of the present invention.

[0014] Figure 2 The acidic polysaccharide PRP-9A extracted from Polygonatum rhizome in this embodiment of the invention. 1 H NMR spectrum;

[0015] Figure 3 The acidic polysaccharide PRP-9A extracted from Polygonatum rhizome in this embodiment of the invention. 13 C NMR spectrum;

[0016] Figure 4 The acidic polysaccharide PRP-9A extracted from Polygonatum rhizome in this embodiment of the invention. 1 H- 1 H COSY spectrum;

[0017] Figure 5 The HMQC spectrum of the extracted Polygonatum odoratum acidic polysaccharide PRP-9A in this embodiment of the invention;

[0018] Figure 6 This is the HMBC pattern of the acidic polysaccharide PRP-9A extracted from Polygonatum rhizome in this embodiment of the invention. Detailed Implementation

[0019] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0020] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0021] Given that this invention isolates and purifies a novel acidic polysaccharide PRP-9A from Polygonatum sibiricum processed by "nine steaming and nine sun-drying", and that this acidic polysaccharide PRP-9A has good hypoglycemic activity and low toxicity, this invention proposes an acidic polysaccharide of Polygonatum sibiricum, its preparation method and application.

[0022] In a typical embodiment of the present invention, an acidic polysaccharide of Polygonatum sibiricum is provided, with a molecular weight of 35.0–45.0 kDa as determined by multi-angle laser light scattering. It is composed of Gal, GalA, Rha, Man, and Ara, with a molar ratio of 50–60:15–25:10–15:5–10:1–4. The monosaccharide linkage types are mainly →4)-β-Galp-(1→, →4)-β-Manp-(1→, →2)-α-Rhap-(1→, →4)-α-GalpA-6-O-Me-(1→, →4)-2-O-acetyl-β-Manp-(1→) and T-α-GalpA-(1→).

[0023] In some embodiments, the chemical structure of the Polygonatum odoratum acidic polysaccharide contains →4)-β-D-Galp-(1→4)-β-D-Galp-(1→ linker fragment, →4)-β-D-Galp-(1→4)-β-D-Manp-(1→ linker fragment, →2)-α-L-Rhap-(1→4)-β-D-Galp-(1→ linker fragment, →4)-α-D-GalpA-6-O-Me-(1→2)-α-L-Rhap-(1→ linker fragment, T-α-D-GalpA-(1→4)-α-D-GalpA-6-O-Me-(1→ linker fragment, →4)-β-D-Manp-(1→4)-2-O-acetyl-β-D-Manp-(1→ linker fragment).

[0024] In some embodiments, the molecular weight determined by multi-angle laser light scattering is 39.0–40.0 kDa.

[0025] In some embodiments, the molar ratio of Gal, GalA, Rha, Man, and Ara is 56–67:19–20:11–12:9–10:2–3.

[0026] In some embodiments, the molar ratio of Gal, GalA, Rha, Man, and Ara is 56.2–56.4:19.4–19.6:11.8–12.0:9.5–9.7:2.7–2.9.

[0027] In another embodiment of the present invention, a method for preparing the above-mentioned acidic polysaccharide of Polygonatum is provided. Raw Polygonatum is steamed and dried nine times to obtain cooked Polygonatum. The cooked Polygonatum is then subjected to water reflux extraction to obtain an aqueous extract. The aqueous extract is subjected to alcohol precipitation, lipid removal, and protein removal to obtain a Polygonatum polysaccharide extract. The Polygonatum polysaccharide extract is eluted using a DEAE-52 ion exchange column chromatography, with water and a 0.1–0.3 M NaCl aqueous solution used sequentially during the elution process. The eluted portion from the 0.1–0.3 M NaCl aqueous solution is purified to obtain the acidic polysaccharide of Polygonatum.

[0028] In some embodiments, alcohol precipitation is performed using an aqueous ethanol solution, wherein the volume fraction of ethanol in the aqueous ethanol solution is 58-62%.

[0029] In some embodiments, the degreasing process is as follows: the crude polysaccharide of Polygonatum odoratum after alcohol precipitation is dissolved in water and extracted with petroleum ether to achieve degreasing.

[0030] In some embodiments, the protein removal process involves extracting the defatted crude polysaccharide aqueous solution of Polygonatum odoratum using Sevage reagent.

[0031] In some embodiments, the purification process includes dialysis to remove salt and freeze drying.

[0032] A third embodiment of the present invention provides an application of the above-mentioned Polygonatum odoratum acidic polysaccharide in the preparation of hypoglycemic products.

[0033] Specifically, the blood sugar lowering product is a blood sugar lowering drug or a blood sugar lowering food.

[0034] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0035] Example

[0036] A method for extracting the acidic polysaccharide PRP-9A from Polygonatum sibiricum, comprising the following steps:

[0037] (1) Raw Polygonatum sibiricum is taken and processed into cooked Polygonatum sibiricum through a "nine-steaming and nine-drying" process. The "nine-steaming and nine-drying" process involves steaming and drying the raw Polygonatum sibiricum nine times. The steaming process involves placing the raw Polygonatum sibiricum on a steamer and heating it with steam for 2 hours, then allowing it to cool naturally to room temperature. The drying process involves drying the cooled steamed Polygonatum sibiricum in an oven at a temperature of 55°C for 5 hours. The above process is repeated nine times to obtain "nine-steaming and nine-drying" Polygonatum sibiricum.

[0038] (2) After pulverizing the obtained processed Polygonatum sibiricum, it was extracted twice by heating and refluxing with water, with a solid-liquid ratio of 1:3 (g / mL), for 2 hours each time. The water extracts were combined, filtered, and concentrated to obtain the water extract.

[0039] (3) Add the concentrated water extract to ethanol-water, adjust the ethanol ratio to 60% ethanol-water, let stand for 24 hours to allow the polysaccharides in the water extract to precipitate completely, filter, and obtain crude polysaccharide of Polygonatum odoratum.

[0040] (4) The crude polysaccharide obtained above was dissolved in water and extracted five times with petroleum ether to remove the lipid-soluble components from the aqueous extract. Subsequently, the polysaccharide aqueous solution after ester removal was extracted five times with Sevage reagent (chloroform: n-butanol = 4:1, v / v) to remove proteins mixed in the polysaccharide. The polysaccharide aqueous solution after protein removal was concentrated under reduced pressure to remove residual organic solvents.

[0041] (5) Take 20g of the polysaccharide extract obtained above after removing esters and proteins, and purify it by DEAE-52 ion exchange column chromatography. Dissolve the sample in water and add it to the top of the DEAE-52 column. First, elute with ultrapure water (2L); then elute with 0.2M NaCl aqueous solution, collecting one tube for every 50mL, for a total of 40 tubes. The polysaccharide content of each tube is determined by the sulfuric acid-phenol method. Combine the eluents rich in polysaccharides and concentrate them under reduced pressure to 100mL.

[0042] (6) The acidic polysaccharide fraction obtained above was eluted with 0.2M NaCl and the NaCl was removed by dialysis. Dialysis was performed using a 3500 Da dialysis bag, and the aqueous solution around the dialysis bag was replaced every 12 hours, for a total of 5 times until the NaCl was completely removed. The resulting acidic sugar solution after dialysis was freeze-dried to obtain a Polygonatum odoratum acidic polysaccharide PRP-9A (1.5 g).

[0043] Structural identification: The isolated acidic polysaccharide PRP-9A from Polygonatum was analyzed by infrared spectroscopy (IR), molecular weight and nuclear magnetic resonance (NMR) spectra using Nicolet IS50, HPGPC high performance liquid chromatography-gel chromatography and Burker AVIII HD 600MHz nuclear magnetic resonance spectrometer, respectively. Its monosaccharide composition and linkage sites were also analyzed. The final NMR data are shown in Table 1, and a new acidic polysaccharide structure was identified.

[0044] PRP-9A is a reddish-brown amorphous powder. Its molecular weight, determined by multi-angle laser light scattering, is 39.5 kDa. The monosaccharide composition of PRP-9A, determined by acid hydrolysis, comprises Gal (56.3%), GalA (19.4%), Rha (11.9%), Man (9.6%), and Ara (2.8%), including five types of monosaccharides. Methylation analysis indicates that the main monosaccharide linkage type of PRP-9A is →4)-β-Galp-(1→,

[0045] →4)-β-Manp-(1→, →2)-α-Rhap-(1→, →4)-α-GalpA-6-O-Me-(1→,

[0046] →4)-2-O-acetyl-β-Manp-(1→ and T-α-GalpA-(1→.

[0047] 3281 cm⁻¹ in the IR spectrum -1 and 2935cm -1 The absorption peak is the stretching vibration peak of OH and CH; 1738 cm⁻¹ -1 and 1601cm -1 The absorption peak is COO - The stretching vibration peak, such as Figure 1 As shown.

[0048] 13 The low-field region of the C-NMR spectrum shows a group of signals with the highest content, δ. C 104.33, is the terminal carbon signal in the →4)-β-D-Galp-(1→ fragment, labeled as the C fragment. In addition, according to... 1 H NMR, 13 C NMR and HMQC spectra, such as Figures 2-3 As shown, PRP-9A is confirmed to contain 9 monosaccharide fragments, namely δ H / C The following values ​​are valued: 5.17 / 109.23, 5.01 / 107.40, 4.37 / 103.55, 4.89 / 100.38, 4.83 / 100.06, 5.02 / 99.43, 4.99 / 98.94, 4.52 / 96.11, and 5.23 / 92.15, labeled as segments A, B, D, E, F, G, H, I, and J. The terminal base signals δ of segments A and B are then analyzed. H / C 5.17 / 109.23 and 5.01 / 107.40, the monosaccharide composition of both was determined to be a pentose sugar with an α configuration, further determined by... 1 H- 1 H COSY and HMQC spectra, such as Figures 4-5 As shown, determine the C-2 to C-5 signals δ of segment A. C / H The values ​​81.3 (4.12), 76.09 (3.92), 83.96 (4.02), 66.16 (3.79 / 3.69) and the C-2 to C-5 signals δ of segment B. C / H 80.8 (4.04), 76.54 (3.85), 82.3 (4.13), 65.59 (3.79 / 3.69) determine that the two are →5)-α-L-Araf(1→ and T-α-L-Araf respectively. The terminal base signals of fragments D and G are δ H / C

[0049] 4.37 / 103.55 and 5.02 / 99.43, respectively, confirmed that both are β-configuration monosaccharides. Further analysis of the C-2 to C-6 signals identified the →4)-β-D-Manp-(1→ and →4)-2-O-acetyl-β-D-Manp-(1→ monosaccharide fragments. Fragments E and F contain the characteristic carbon signal δ of GalpA. C 174.9 and 175.3, the terminal base signals are δ H / C 4.89 / 100.38 and 4.83 / 100.06, combined with the C-2 to C-5 signals, determine that they are T-α-D-GalpA-(1→ and

[0050] →4)-α-D-GalpA-6-O-Me-(1→ monosaccharide fragment. The terminal group signals of fragments H, I, and J are δ H / C

[0051] 4.99 / 98.94, 4.52 / 96.11, and 5.23 / 92.15, combined with signals C-2 to C-6, determine that the three are respectively

[0052] →2)-α-L-Rhap-(1→,→4,6)-α-D-Galp(1→ and α-D-Glcp(1→ monosaccharide fragments.

[0053] The linking order of the various monosaccharide fragments was determined using the correlation signal of HMBC. In the HMBC spectrum, such as... Figure 6 As shown, the correlation signal of H-1(C) / C-4(C) indicates the presence of

[0054] →4)-β-D-Galp-(1→4)-β-D-Galp-(1→connection fragment; the correlation signal of H-4(D) / C-1(C) indicates the presence of →4)-β-D-Galp-(1→4)-β-D-Manp-(1→connection fragment; the correlation signal of H-1(H) / C-4(C) indicates the presence of →2)-α-L-Rhap-(1→4)-β-D-Galp-(1→connection fragment; the correlation signal of H-1(F) / C-2(H) indicates the presence of →4)-α-D-GalpA-6-O- Me-(1→2)-α-L-Rhap-(1→linker fragment; the correlation signals of H-1(E) / C-4(F) indicate the presence of T-α-D-GalpA-(1→4)-α-D-GalpA-6-O-Me-(1→linker fragment; the correlation signals of H-4(G) / C-1(D) indicate the presence of →4)-β-D-Manp-(1→4)-2-O-acetyl-β-D-Manp-(1→linker fragment. In summary, the structure of PRP-9A is finally determined to be a new acidic polysaccharide of Polygonatum odoratum.

[0055]

[0056] Table 1 PRP-9A 1 H NMR (600MHz, D2O) and 13 C10 NMR data (150MHz, D2O)

[0057]

[0058] Pharmacological experiments:

[0059] Study on the hypoglycemic activity of Polygonatum odoratum acidic polysaccharide PRP-9A:

[0060] 1. Establishment of an insulin-resistant hyperglycemic cell model

[0061] HepG2 cell lines were incubated in a 5% CO2, 37°C cell culture incubator using DMEM high-glucose medium (containing 100 U / mL penicillin, 100 mg / mL streptomycin, and 10% fetal bovine serum) until they reached logarithmic proliferation, at which point they were passaged. In 96-well cell plates, 1 × 10⁻⁶ cells were added to each well. 6 200 μL of cell suspension per 100 cells / mL was cultured adherently for 24 h. A control group and an insulin-resistant hyperglycemic model group were established to construct the hyperglycemic cell model. The control group was given 200 μL of DMEM high-glucose medium, while the insulin-resistant hyperglycemic model group was given 200 μL of DMEM high-glucose medium containing 0.06 mmol / L palmitic acid to construct the hyperglycemic cell model.

[0062] 2. Cell viability assay of acidic polysaccharide PRP-9A

[0063] Using the aforementioned cell model, activity screening was conducted by setting up a blank control group, an insulin-resistant hyperglycemic model group, a positive control group, and a polysaccharide-treated group. The blank control group was given 200 μL of DMEM high-glycemic medium, the insulin-resistant hyperglycemic model group was given 200 μL of DMEM high-glycemic medium containing 0.06 mmol / L palmitic acid, the positive control group was given 200 μL of medium containing 0.5 mg / mL metformin (containing 0.06 mmol / L palmitic acid), and the treated groups were given 200 μL of medium containing 0.5, 1.0, and 1.5 mg / mL of Polygonatum sibiricum acidic polysaccharide PRP-9A (containing 0.06 mmol / L palmitic acid). Each compound was tested in triplicate. After 48 hours of culture, cell viability was first determined by adding 15 μL of 15 mg / mL MTT solution to each well, incubating in the dark for 4 hours, then discarding the supernatant, adding 200 μL of DMSO to each well, shaking, and measuring the absorbance (A) of each well at 490 nm using a multi-functional microplate reader to calculate the cell viability of compound PRP-9A.

[0064] 3. Screening of hypoglycemic activity of acidic polysaccharide PRP-9A

[0065] Using the above cell model, activity screening was conducted by setting up a blank control group, an insulin-resistant hyperglycemic model group, a positive control group, and a polysaccharide treatment group. The blank control group was given 200 μL of DMEM high-glycemic medium; the insulin-resistant hyperglycemic model group was given 200 μL of DMEM high-glycemic medium containing 0.06 mmol / L palmitic acid; the positive control group was given 200 μL of medium containing 0.5 mg / mL metformin (containing 0.06 mmol / L palmitic acid); and the treatment groups were given 200 μL of medium containing 0.5, 1.0, and 1.5 mg / mL of Polygonatum sibiricum acidic polysaccharide PRP-9A (containing 0.06 mmol / L palmitic acid), with three replicates for each concentration. After 48 h of culture, glucose consumption was measured using a glucose consumption assay kit, and the hypoglycemic activity of the acidic polysaccharide PRP-9A was calculated. The results are shown in Table 2.

[0066] Table 2. Hypoglycemic activity of Polygonatum odoratum acidic polysaccharide PRP-9A

[0067]

[0068] The cell viability of HepG2 cells was determined using the MTT assay. Table 2 shows that three different concentrations of PRP-9A did not significantly inhibit the growth of HepG2 cells, with cell viability exceeding 80%. Furthermore, the cell viability of all three concentrations of PRP-9A was higher than that of the positive control, indicating low cytotoxicity of PRP-9A. The hypoglycemic activity of the three different concentrations of PRP-9A was determined using an insulin-resistant hyperglycemic cell model. Table 2 shows that PRP-9A exhibits concentration-dependent hypoglycemic activity. The highest glucose consumption (9.5 mM) was observed with 1.5 mg / mL PRP-9A, slightly lower than the positive control and approximately twice that of the model group.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An acidic polysaccharide from Polygonatum odoratum, characterized in that, The molecular weight, determined by multi-angle laser light scattering, ranged from 35.0 to 45.0 kDa. It was composed of Gal, GalA, Rha, Man, and Ara, with a molar ratio of 50–60:15–25:10–15:5–10:1–4. The main monosaccharide linkage type was →4)-β-Gal. p -(1→、→4)-β-Man p- (1→、→2)-α-Rha p- (1→、→4)-α-Gal p A-6-O-Me - (1→,→4)-2-O-acetyl-β-Man p- (1→ and T-α-Gal p A - (1→; The preparation method of the acidic polysaccharide of Polygonatum includes: steaming and sun-drying raw Polygonatum nine times to obtain cooked Polygonatum; extracting the cooked Polygonatum by water reflux to obtain an aqueous extract; subjecting the aqueous extract to alcohol precipitation, lipid removal, and protein removal to obtain a Polygonatum polysaccharide extract; eluting the Polygonatum polysaccharide extract using DEAE-52 ion exchange column chromatography, wherein water and a 0.1-0.3 M NaCl aqueous solution are used sequentially during the elution process; and purifying the eluted portion with the 0.1-0.3 M NaCl aqueous solution yields the acidic polysaccharide of Polygonatum.

2. The Polygonatum odoratum acidic polysaccharide as described in claim 1, characterized in that, The chemical structure of the acidic polysaccharide from Polygonatum contains →4)-β-D-Gal p -(1→4)-β-D-Gal p -(1→connecting fragment,→4)-β-D-Gal p -(1→4)-β-D-Man p- (1→connecting fragment, →2)-α-L-Rha p- (1→4)-β-D-Gal p -(1→connecting fragment,→4)-α-D-Gal p A-6-O-Me - (1→2)-α-L-Rha p- (1→Connecting fragment, T-α-D-Gal) p A - (1→4)-α-D-Gal p A-6-O-Me - (1→connecting fragments, →4)-β-D-Man p- (1→4)-2-O-acetyl-β-D-Man p- (1→Connecting fragments) 3. The Polygonatum odoratum acidic polysaccharide as described in claim 1, characterized in that, The molecular weight determined by multi-angle laser light scattering method is 39.0~40.0 kDa.

4. The Polygonatum odoratum acidic polysaccharide as described in claim 1, characterized in that Ga... The molar ratio of l, GalA, Rha, Man and Ara is 56~67:19~20:11~12:9~10:2~3.

5. The Polygonatum odoratum acidic polysaccharide as described in claim 1, characterized in that Ga... The molar ratio of l, GalA, Rha, Man and Ara is 56.2~56.4:19.4~19.6:11.8~12.0:9.5~9.7:2.7~2.

9.

6. A method for preparing the acidic polysaccharide of Polygonatum odoratum according to any one of claims 1 to 5, characterized in that, Raw Polygonatum sibiricum was steamed and dried nine times to obtain processed Polygonatum sibiricum. The processed Polygonatum sibiricum was then subjected to water reflux extraction to obtain an aqueous extract. The aqueous extract was then subjected to alcohol precipitation, lipid removal, and protein removal to obtain a Polygonatum sibiricum polysaccharide extract. The Polygonatum sibiricum polysaccharide extract was eluted using a DEAE-52 ion exchange column chromatography, with water and 0.1-0.3 M NaCl aqueous solution used sequentially during the elution process. The eluted portion with 0.1-0.3 M NaCl aqueous solution was purified to obtain the Polygonatum sibiricum acidic polysaccharide.

7. The method for preparing the acidic polysaccharide of Polygonatum odoratum as described in claim 6, characterized in that, Alcohol precipitation was performed using an aqueous ethanol solution, wherein the volume fraction of ethanol in the aqueous ethanol solution was 58-62%.

8. The method for preparing the acidic polysaccharide of Polygonatum odoratum as described in claim 6, characterized in that, The degreasing process is as follows: the crude polysaccharide of Polygonatum odoratum after alcohol precipitation is dissolved in water and extracted with petroleum ether to achieve degreasing.

9. The method for preparing the acidic polysaccharide of Polygonatum odoratum as described in claim 6, characterized in that, The protein removal process involved extracting the lipid-depleted crude polysaccharide aqueous solution from the Sevage reagent.

10. The method for preparing the acidic polysaccharide of Polygonatum odoratum as described in claim 6, characterized in that, The purification process includes dialysis to remove salt and freeze drying.

11. The use of the Polygonatum odoratum acidic polysaccharide according to any one of claims 1 to 5 in the preparation of hypoglycemic products.

12. The application as described in claim 11, characterized in that, The blood sugar lowering product is a blood sugar lowering drug.

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