Coix seed oligosaccharide, preparation method therefor, and use thereof

Abstract

The present invention relates to the technical field of medicine, and in particular to a coix seed oligosaccharide (CSO), a preparation method therefor, and a use thereof. The CSO is a CSO separated and purified from coix seeds. The CSO has a molecular weight of 1847 Da and comprises glucose and a trace amount of galactose in a molar ratio of 96.5:3.5. The preparation method comprises: subjecting coix seeds to water reflux extraction, performing alcohol precipitation, fat removal, and protein removal to obtain a coix seed polysaccharide, and sequentially treating the coix seed polysaccharide by using α-amylase and glycosidase; separating the treated coix seed polysaccharide by means of DEAE-52 ion exchange column chromatography; and then eluting the resulting material by means of a Sephadex G-25 column to obtain a CSO. Structural analysis is performed on the CSO by means of infrared and gel chromatography, and it has been determined that the CSO comprises glucose and a trace amount of galactose in a molar ratio of 96.5:3.5. The oligosaccharide has relatively good uric acid-lowering activity, hypoglycemic activity, and anti-inflammatory activity, has low toxic and side effects, and exhibits good development prospects.

Description

A Job's Tears Oligosaccharide, Its Preparation Method and Application Technical Field

[0001] This invention belongs to the field of pharmaceutical technology, specifically relating to a coix seed oligosaccharide, its preparation method, and its application. Background Technology

[0002] Job's tears (Coix lacryma-jobi L. var. mayuen (Roman.) Stapf), a plant belonging to the Liliaceae family and the Poaceae family, is a dried, mature seed. It has diuretic, spleen-strengthening, diarrhea-relieving, pain-relieving, pus-draining, detoxifying, and nodule-dispersing effects. Job's tears is also widely used as a functional food. It contains many chemical components, mainly polysaccharides, fatty acids, esters, phenols, amino acids, and proteins. Among these, starch-based polysaccharides are the main components, exerting various pharmacological effects, including lowering uric acid, lowering blood sugar, anti-tumor activity, regulating intestinal microbiota, and anti-inflammation. However, the mechanism of action of Job's tears in lowering uric acid is currently unclear, and the water solubility of Job's tears polysaccharides is poor. Therefore, finding novel, safe, and highly effective uric acid-lowering components is of great significance.

[0003] Coix seed oligosaccharides, also known as oligosaccharides, are low-degree polymeric sugars composed of 3-10 monosaccharide molecules linked by α-1,4 glycosidic bonds. Currently, common extraction processes for coix seed oligosaccharides include enzymatic hydrolysis, biological methods, solvent extraction, ultrasonic-assisted extraction, and steam explosion technology. However, these methods suffer from drawbacks such as uncontrollable degradation processes and the generation of harmful byproducts, posing significant obstacles to the industrial-scale preparation of coix seed oligosaccharides. Furthermore, there are no reports of coix seed oligosaccharides exhibiting uric acid-lowering activity. Summary of the Invention

[0004] The purpose of this invention is to provide a coix seed oligosaccharide, its preparation method, and its application, thereby overcoming the shortcomings of the prior art, fully exploring the pharmacological effects of coix seed polysaccharides, studying the polysaccharide components of coix seed, and isolating a new oligosaccharide component. The obtained oligosaccharide component has strong uric acid-lowering activity and low toxicity and side effects, and has good development prospects.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for preparing coix seed oligosaccharides, comprising the following steps:

[0007] (1) Coix seed powder was mixed with water and extracted to obtain coix seed extract. After concentration, ethanol was added to precipitate the extract to obtain coix seed polysaccharide.

[0008] (2) After mixing coix seed polysaccharide with water, enzymatic hydrolysis was performed, and the enzymatic reaction was terminated by heating to obtain coix seed polysaccharide solution;

[0009] (3) After filtering the Coix Seed Polysaccharide solution, the Coix Seed Polysaccharide Extract was obtained. After concentration, ethanol was added to precipitate the extract. After redissolving in water and freeze-drying, Coix Seed Crude Oligosaccharide was obtained.

[0010] (4) After mixing the crude oligosaccharide of coix seed with water, the mixture was separated by ion exchange chromatography and eluted with water / NaCl to obtain water-eluted oligosaccharide;

[0011] (5) The water-eluted oligosaccharide was separated by gel filtration chromatography and eluted with water to obtain coix seed oligosaccharide.

[0012] In some other embodiments, in step (1), the ratio of coix seed powder to water is 1:(10-15)g / mL, the extraction temperature is 55-65℃, and the extraction time is 2-5h.

[0013] In some other embodiments, in step (2), the ratio of coix seed polysaccharide to water is 1:(30-60)mg / mL; the enzymatic hydrolysis is performed by sequentially treating with α-amylase and α-1,4-glucose hydrolase.

[0014] The conditions for terminating the enzyme reaction by heating are: heating temperature of 90-100℃ and time of 5-10 min.

[0015] In some other embodiments, in step (2), the conditions for the α-amylase treatment are: the amount of α-amylase added is 1.5-3.0 wt.%, the enzyme activity is 3000-5000 U / g, the temperature is 50-60℃, and the time is 2-3h;

[0016] The conditions for the glycosidase treatment are as follows: the amount of α-1,4-glucose hydrolase added is 1.0-2.0 wt.%, the enzyme activity is 50,000-100,000 U / g, the temperature is 50-60℃, and the time is 30-60 min.

[0017] In some other embodiments, in step (3), the extraction is performed by sequentially adding petroleum ether and Sevage reagent;

[0018] In step (1) or step (3), the volume concentration of ethanol is 75-85%, the precipitation temperature is 1-5℃, and the precipitation time is 10-20h.

[0019] In some other embodiments, in step (4), the ratio of the coix seed crude oligosaccharide to water is 1:(30-60)mg / mL;

[0020] The ion exchange chromatography separation conditions were as follows: a DEAE-52 column was used, and elution was performed with water, 0.1 mol / L NaCl aqueous solution, 0.2 mol / L NaCl aqueous solution, 0.3 mol / L NaCl aqueous solution, and 0.4 mol / L NaCl, respectively.

[0021] In some other embodiments, in step (5), the conditions for gel filtration chromatography separation are: using a Sephadex G-25 column and a water flow rate of 0.1-0.2 mL / min.

[0022] Secondly, the present invention provides a coix seed oligosaccharide prepared by the preparation method of the coix seed oligosaccharide described in the first aspect, wherein the coix seed oligosaccharide has a molecular weight of 1847 Da and is composed of glucose and galactose.

[0023] In some other embodiments, the molar ratio of glucose to galactose is 96.5:3.5.

[0024] Thirdly, the present invention provides the use of the coix seed oligosaccharide described in the second aspect in the preparation of drugs with uric acid-lowering, blood sugar-lowering, or anti-inflammatory activities.

[0025] The beneficial effects of this invention are:

[0026] (1) This invention isolates and purifies an oligosaccharide CSO from Coix seed, and the obtained oligosaccharide has good uric acid lowering activity, blood sugar lowering activity and anti-inflammatory activity, and has low toxicity and side effects, and has good development prospects.

[0027] (2) This invention uses a combination of hyperuricemia animal model and drug administration. By measuring serum uric acid content and H&E staining kidney sections, the mechanism of the uric acid-lowering activity of coix seed oligosaccharide was clarified, providing a scientific approach. Attached Figure Description

[0028] 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.

[0029] Figure 1 shows the elution curve of crude oligosaccharides from Coix seed monitored by the phenol-sulfuric acid method in an embodiment of the present invention;

[0030] Figure 2 shows the elution curves of oligosaccharides in the water-eluted region monitored by the phenol-sulfuric acid method in an embodiment of the present invention.

[0031] Figure 3 is an infrared spectrum of coix seed oligosaccharide in an embodiment of the present invention;

[0032] Figure 4 shows the uric acid-lowering activity results of coix seed oligosaccharides in the embodiments of the present invention;

[0033] Figure 5 shows the results of the reduction of kidney damage by coix seed oligosaccharide in the embodiments of the present invention;

[0034] Figure 6 is a kidney section stained with H&E from coix seed oligosaccharide in an embodiment of the present invention;

[0035] Figure 7 shows the hypoglycemic activity results of coix seed oligosaccharide in the embodiments of the present invention, where (a) represents HepG2 cell viability and (b) represents glucose consumption. Detailed Implementation

[0036] Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the invention. Specific conditions not specified in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Components whose manufacturers are not specified are all commercially available conventional products.

[0037] Example 1

[0038] I. Preparation method of Coix Seed Oligosaccharides, the steps are as follows:

[0039] (1) Coix seed (from Baiweitang Chinese Herbal Pieces Co., Ltd.) was pulverized to obtain coix seed powder (mesh size 20-40). The coix seed powder (500g) was extracted with distilled water (1:10, w / v, g / mL) at 60℃ for 3 hours. The extract was then filtered, concentrated, and precipitated overnight at 4℃ with 80% ethanol (v / v) to obtain coix seed polysaccharide (51g).

[0040] (2) Dissolve coix seed polysaccharide in deionized water (1:50, w / v), treat with 2% α-amylase (enzyme activity 4000 U / g) at 60℃ for 2 h, then treat with 1% α-1,4-glucose hydrolase (enzyme activity 100,000 U / g) for 40 min, and then heat at 100℃ for 5 min to terminate the enzyme reaction.

[0041] (3) After filtration, the extract was extracted five times with petroleum ether to remove the lipid-soluble components from the aqueous extract. Subsequently, the lipid-free polysaccharide aqueous solution was extracted five times with Sevage reagent (chloroform: n-butanol = 4:1, v / v) to remove any proteins mixed in with the polysaccharide. The protein-free polysaccharide aqueous solution was concentrated under reduced pressure to remove residual organic solvents. It was then precipitated overnight with 80% ethanol (v / v), filtered to obtain precipitated oligosaccharides, reconstituted with water, and lyophilized (-20℃) to obtain crude coix seed oligosaccharides (36.9 g, relative to 500 g coix seed powder, the yield of crude coix seed oligosaccharides was 36.9 / 500 = 7.38%).

[0042] (4) The crude oligosaccharide from Coix seed was mixed with deionized water to prepare a Coix seed crude oligosaccharide solution with a concentration of 50 mg / mL. Ion exchange chromatography was performed using a DEAE-52 column (6.3 × 45 cm), with elution using water, 0.1 mol / L NaCl aqueous solution, 0.2 mol / L NaCl aqueous solution, 0.3 mol / L NaCl aqueous solution, and 0.4 mol / L NaCl aqueous solution, respectively. Each gradient elution volume was 1.5 L, and one tube was collected for every 50 mL. The elution curve was monitored using the phenol-sulfuric acid method, as shown in Figure 1. A total of 30 tubes were collected at a wavelength of 490 nm, yielding the water-eluted oligosaccharide fraction (27.5 g) with relatively high absorbance.

[0043] (5) The oligosaccharides in the water elution fraction were further separated by gel filtration chromatography using a Sephadex G-25 column (1.6×100cm). Distilled water was used for elution at a flow rate of 0.2mL / min and an elution volume of 1.5L. One tube was collected for every 50mL, and a total of 30 tubes were collected at a wavelength of 490nm.

[0044] The elution curve was monitored using the phenol-sulfuric acid method, as shown in Figure 2. The oligosaccharides collected from tubes 17-24 with high absorbance were freeze-dried to obtain coix seed oligosaccharide (CSO, 19.4 g).

[0045] During the research process, the inventors also used other extraction methods for coix seed oligosaccharides, the specific extraction process of which is as follows:

[0046] The coix seed material was pulverized to obtain coix seed powder, which was then extracted with distilled water (1:5, w / v, g / mL) at 50℃ for 3 hours. The extract was then filtered, concentrated, and precipitated overnight with 80% ethanol (v / v) at 4℃ to obtain coix seed polysaccharide (34g).

[0047] Coix seed polysaccharide was dissolved in deionized water (1:50, w / v), treated with 1% α-amylase (enzyme activity 4000 U / g) at 60℃ for 2 h, then treated with 0.5% α-1,4-glucose hydrolase (enzyme activity 100,000 U / g) for 40 min, and then heated at 100℃ for 5 min to terminate the enzyme reaction.

[0048] After filtration, the extract was extracted five times with petroleum ether to remove lipid-soluble components. Subsequently, the lipid-free polysaccharide aqueous solution was extracted five times with Sevage's reagent (chloroform: n-butanol = 4:1, v / v) to remove any proteins mixed in with the polysaccharide. The protein-free polysaccharide aqueous solution was concentrated under reduced pressure to remove residual organic solvents. Precipitation was then carried out overnight with 80% ethanol (v / v), filtered to obtain precipitated oligosaccharides, reconstituted with water, and lyophilized (-20℃) to obtain crude coix seed oligosaccharides (21.3 g, yield of crude coix seed oligosaccharides relative to 500 g of coix seed powder: 21.3 / 500 = 4.26%). It is evident that the yield of crude coix seed oligosaccharides in this extraction method is low, resulting in poor quality and efficacy of the final product, coix seed oligosaccharides.

[0049] II. Structural Identification of Coix Seed Oligosaccharides

[0050] The structural characteristics of coix seed oligosaccharides (CSO) were preliminarily analyzed using Fourier transform infrared spectroscopy, and the results are shown in Figure 3. Figure 3 shows that coix seed oligosaccharides exhibit characteristics at 3235 cm⁻¹. -1 A large stretching peak appears at 2924 ccm. -1 An absorption peak appears at 1631 cm⁻¹, corresponding to the stretching vibrations of OH and CH, respectively; this is a typical characteristic of sugar absorption spectra. -1 The peak at 1433 cm⁻¹ is attributed to the presence of bound water in the sugar. -1 and 1350 cm -1 The absorption peaks at these locations indicate angular distortions of the -CH and -CH2 groups. Furthermore, the absorption peaks at 1200-1000 cm⁻¹ indicate... -1 Peak within the range (1124 cm) -1 1085 cm -1 and 1045 cm -1 This is attributed to the stretching vibrations of COH, CC, and COC, consistent with the structure of the pyranose ring. (907 cm⁻¹) -1 and 840 cm -1 The peak at that location indicates the presence of β- and α-glucopyranose bonds.

[0051] The molecular weight and distribution of coix seed oligosaccharides (CSO) were separated and determined by high-performance gel permeation chromatography (HPGPC). HPGPC chromatograms showed a single symmetrical peak for CSO, confirming its molecular weight as 1847 Da. Monosaccharide composition analysis revealed that CSO consisted of glucose and trace amounts of galactose in a molar ratio of 96.5:3.5.

[0052] III. Pharmacological Experiments

[0053] 1. Study on the uric acid-lowering activity of coix seed oligosaccharides (CSO)

[0054] (1) Establishment of an animal model of hyperuricemia

[0055] Specific pathogen-free (SPF-grade) Kunming male mice (sourced from Beijing Vital River Laboratory Animal Technology Co., Ltd.) were randomly divided into two groups: a normal group (KB) and a model group (250 mg / kg). -1 ·d -1 Potassium oxonate + 250 mg / kg -1 ·d -1 Hypoxanthine), positive control group (4 mg / kg) -1 Allopurinol) and treatment groups (low dose 50 mg / kg CSO-L; medium dose 100 mg / kg CSO-M; high dose 200 mg / kg CSO-H).

[0056] A combined modeling and drug administration approach was used. Mice in the model group, positive drug group, and drug administration group were intraperitoneally injected with hypoxanthine and administered potassium oxonate by gavage. One hour later, they were administered different doses of coix seed oligosaccharide and allopurinol (positive control) by gavage. Mice in the normal group and model group were administered an equal volume of physiological saline by gavage for 3 weeks. Twenty days after drug administration, the mice were fasted but allowed to drink water. On day 21, one hour after the administration of the modeling agent, blood was collected from the mouse eyeballs, centrifuged to obtain the serum for testing, and stored at -20℃ for later use.

[0057] (2) Uric acid-lowering activity assay

[0058] The uric acid content in mouse serum was analyzed and determined using HPLC. The HPLC conditions were as follows: Waters Summetry C18 column (4.6 μm × 250 mm, 5 μm); mobile phase A consisted of 0.52 mmol / L sodium pentanesulfonate and 0.20 mol / L potassium monophosphate aqueous solution, with the pH adjusted to 4.0 by adding HPLC-grade phosphoric acid; mobile phase B consisted of acetonitrile; separation conditions were isocratic 5% acetonitrile; detection wavelength was 254 nm; flow rate was 1 mL / min; and column temperature was 25℃. A standard curve was established using different concentrations of uric acid standard (Shanghai Aladdin Biochemical Technology Co., Ltd. U105582) as the x-axis and peak area as the y-axis, to determine the uric acid content. The regression equation for the uric acid content was y = 3390.8x - 5.57. The uric acid content produced by the system could be calculated by substituting the measured peak area (y) into the standard curve.

[0059] (3) Experimental Results

[0060] Figure 4 shows the results of the uric acid-lowering activity test of coix seed oligosaccharides. As can be seen from Figure 4, the serum uric acid (UA) level in the model group reached 240.54 μmol / L, approximately 3.76 times that of the normal group, confirming the successful establishment of the hyperuricemia (HUA) model. CSO treatment significantly reduced serum UA levels, with the high-dose group (CSO-H) showing the most significant effect, reducing serum UA to 53.27 μmol / L. Compared with the normal group, the liver xanthine oxidase (XOD) activity in the model group was significantly increased to 13.27 U / gprot (p<0.01), while the coix seed oligosaccharide treatment group reduced XOD activity in a dose-dependent manner, with the high-dose group (CSO-H) showing the most significant effect, reducing it to 9.56 U / gprot, thus indicating that coix seed oligosaccharides have uric acid-lowering activity.

[0061] The results of the test on the effect of coix seed oligosaccharide on reducing kidney injury are shown in Figure 5. As can be seen from Figure 5, the kidney coefficient in the model group (Model) was significantly increased (p<0.01), indicating kidney injury caused by HUA. Conversely, treatment with coix seed oligosaccharide in the treatment group significantly reduced the kidney coefficient (p<0.01), indicating its protective effect on kidney health in HUA mice. Serum creatinine (serum CR) and BUN (a marker of kidney injury and glomerular filtration efficiency) were also significantly increased in the model group (Model) (p<0.01). However, compared with the model group (Model), treatment with coix seed oligosaccharide in the treatment group reduced serum CR and BUN levels (p<0.01). This demonstrates that coix seed oligosaccharide has a role in reducing kidney injury.

[0062] (4) Histopathological analysis

[0063] Figure 6 shows H&E-stained kidney sections from HUA mice. Histopathological analysis further confirmed the protective effect of coix seed oligosaccharides on HUA mice. As shown in Figure 6, the H&E-stained kidney sections from the normal group (Normal) exhibited normal glomeruli, clear tubular boundaries, and intact epithelial cells. Conversely, the model group (Model) showed renal tubular dilation, epithelial cell shedding, renal tubular structural damage, and inflammatory infiltration. Treatment with coix seed oligosaccharides effectively alleviated these changes and restored the integrity of renal tubules and epithelial cells, thus demonstrating the protective effect of coix seed oligosaccharides on HUA mice.

[0064] 2. Study on the hypoglycemic activity of coix seed oligosaccharides (CSO)

[0065] (1) Cell Culture

[0066] HepG2 cells were cultured in DMEM medium containing 10% fetal bovine serum, 100 U / mL penicillin, and 100 μg / mL streptomycin, and incubated at 37°C with 5% CO2. When the HepG2 cells reached approximately 80% confluence, the medium was removed, and the cells were washed twice with 1×PBS. Subsequently, trypsin was added to promote cell detachment, and the cells were passaged at a 1:2 ratio.

[0067] (2) Effects on HepG2 cell viability and glucose consumption

[0068] First, HepG2 cells were seeded in 96-well plates (2 × 10⁻⁶ cells per well). 4 Cells were incubated in DMEM (cells / well) at 37°C for 24 h. Afterward, the medium was replaced with DMEM supplemented with 0.6 mM palmitic acid (PA), and the cells were incubated for another 24 h. Finally, DMEM containing 0.6 mM PA (CSO, 0.40, 0.80, and 1.20 mg / mL) was added again, and the cells were incubated for 24 h. Cell viability was assessed using the MTT assay. Glucose consumption was determined using the glucose oxidase method according to the kit manufacturer's instructions.

[0069] (3) Experimental Results

[0070] The effects of coix seed oligosaccharides on HepG2 cell viability and glucose consumption are shown in Figure 7, where (a) represents HepG2 cell viability and (b) represents glucose consumption. HepG2 cells (IR-HepG2) were treated with 0.6 mM PA for 24 h to induce insulin resistance. Cell viability analysis showed that different concentrations of CSO had little effect on cytotoxicity (Figure 7a). As shown in Figure 7b, glucose uptake in the model group was significantly reduced (p<0.05), indicating the successful establishment of the IR-HepG2 cell model. After treatment with different concentrations of CSO (0.40, 0.80, and 1.20 mg / mL), glucose consumption in IR-HepG2 cells increased in a dose-dependent manner. Specifically, at CSO concentrations of 0.80 and 1.20 mg / mL, glucose consumption increased to 8.43 mM and 8.95 mM, respectively, approximately 1.43 times and 1.51 times that of the model group. These findings suggest that CSO can enhance glucose consumption in IR-HepG2 cells.

[0071] 3. Study on the anti-inflammatory activity of coix seed oligosaccharides (CSO)

[0072] (1) CSO toxicity assay on RAW264.7 mouse macrophages

[0073] Evaluation was performed using the MTT assay. RAW264.7 mouse macrophages were collected, counted, and seeded into 96-well cell culture plates (2 × 10⁶ cells / well).5 / well), cultured for 24 h. The experiment was divided into a negative control group, an LPS group (lipopolysaccharide), a drug-treated group, and a positive control group (dexamethasone). The negative control group only contained culture medium, the LPS group only contained 1 μg / mL LPS, the positive control group contained 1 μg / mL LPS and 20 μM dexamethasone, and the drug-treated group contained 1 μg / mL LPS and 20 μM coix seed oligosaccharide (CSO). Freshly prepared serum-free culture medium containing 5.0 mg / mL MTT was added to each well, and the mixture was cultured at 37°C for 4 h. The supernatant was then removed. 150 μL of DMSO was added to each well to dissolve the formazan precipitate. The optical density at 570 nm was measured using a Perkin Elmer EnSpire microplate reader.

[0074] (2) Anti-inflammatory activity assay

[0075] RAW264.7 mouse macrophages were collected, counted, and seeded into 96-well cell culture plates (2×10⁻⁶). 5 / well). Cells were cultured in DMEM medium containing a mixture of 10% bovine fetal serum and 1% penicillin-streptomycin and incubated at 37°C with 5% CO2 saturated humidity for 24 hours. The experiment included a negative control group, an LPS group, a drug-treated group, and a positive control group (dexamethasone). The negative control group received only culture medium, the LPS group received only 1 μg / mL LPS, the positive control group received 1 μg / mL LPS and dexamethasone (2 μM), and the drug-treated group received 1 μg / mL LPS (lipopolysaccharide) and CSO (0.8 mg / mL). 60 μL of the supernatant was collected, and Griess reagent was added. After 10 minutes, the OD values ​​of each compound were measured at 570 nm using a Perkin Elmer EnSpire microplate reader. The measurement was repeated three times, and the corresponding NO production inhibition rate was calculated.

[0076] (3) Experimental Results

[0077] The results of the toxicity and anti-inflammatory activities of the negative control group, coix seed oligosaccharide (CSO), and positive control group (dexamethasone) on RAW264.7 cells are shown in Table 1.

[0078] Table 1. Results of toxicity and anti-inflammatory activity assays on RAW264.7 cells.

[0079]

[0080] Table 1 shows that coix seed oligosaccharide (CSO) has no cytotoxic effect on RAW264.7 mouse macrophages, but it inhibits LPS (lipopolysaccharide)-induced NO release from RAW264.7 mouse macrophages, with an inhibition rate of 55.2%. This indicates that coix seed oligosaccharide (CSO) has anti-inflammatory activity.

[0081] 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. A method for preparing coix seed oligosaccharides, characterized in that, Includes the following steps: (1) Coix seed powder was mixed with water and extracted to obtain coix seed extract. After concentration, ethanol was added to precipitate the extract to obtain coix seed polysaccharide. (2) After mixing coix seed polysaccharide with water, enzymatic hydrolysis was performed, and the enzymatic reaction was terminated by heating to obtain coix seed polysaccharide solution; (3) After filtering the Coix Seed Polysaccharide solution, the Coix Seed Polysaccharide Extract was obtained. After concentration, ethanol was added to precipitate the extract. After redissolving in water and freeze-drying, Coix Seed Crude Oligosaccharide was obtained. (4) After mixing the crude oligosaccharide of coix seed with water, the mixture was separated by ion exchange chromatography and eluted with water / NaCl to obtain water-eluted oligosaccharide; (5) The water-eluted oligosaccharide was separated by gel filtration chromatography and eluted with water to obtain coix seed oligosaccharide.

2. The method for preparing coix seed oligosaccharides according to claim 1, characterized in that, In step (1), the ratio of coix seed powder to water is 1:(10-15)g / mL, the extraction temperature is 55-65℃, and the extraction time is 2-5h.

3. The method for preparing coix seed oligosaccharides according to claim 1, characterized in that, In step (2), the ratio of coix seed polysaccharide to water is 1:(30-60)mg / mL; the enzymatic hydrolysis is performed by sequentially treating with α-amylase and α-1,4-glucose hydrolase. The conditions for terminating the enzyme reaction by heating are: heating temperature of 90-100℃ and time of 5-10 min.

4. The method for preparing coix seed oligosaccharides according to claim 3, characterized in that, In step (2), the conditions for α-amylase treatment are as follows: the amount of α-amylase added is 1.5-3.0 wt.%, the enzyme activity is 3000-5000 U / g, the temperature is 50-60℃, and the time is 2-3 h; The conditions for the glycosidase treatment are as follows: the amount of α-1,4-glucose hydrolase added is 1.0-2.0 wt.%, the enzyme activity is 50,000-100,000 U / g, the temperature is 50-60℃, and the time is 30-60 min.

5. The method for preparing coix seed oligosaccharides according to claim 1, characterized in that, In step (3), the extraction is performed by sequentially adding petroleum ether and Sevage reagent; In step (1) or step (3), the volume concentration of ethanol is 75-85%, the precipitation temperature is 1-5℃, and the precipitation time is 10-20h.

6. The method for preparing coix seed oligosaccharides according to claim 1, characterized in that, In step (4), the ratio of the coix seed crude oligosaccharide to water is 1:(30-60)mg / mL; The ion exchange chromatography separation conditions were as follows: a DEAE-52 column was used, and elution was performed with water, 0.1 mol / L NaCl aqueous solution, 0.2 mol / L NaCl aqueous solution, 0.3 mol / L NaCl aqueous solution, and 0.4 mol / L NaCl, respectively.

7. The method for preparing coix seed oligosaccharides according to claim 1, characterized in that, In step (5), the conditions for gel filtration chromatography separation are as follows: using a Sephadex G-25 column and a water flow rate of 0.1-0.2 mL / min.

8. The coix seed oligosaccharide prepared by the method of any one of claims 1-7, characterized in that, The molecular weight of the coix seed oligosaccharide is 1847 Da, and the coix seed oligosaccharide is composed of glucose and galactose.

9. The coix seed oligosaccharide according to claim 8, characterized in that, The molar ratio of glucose to galactose is 96.5:3.

5.

10. The use of the coix seed oligosaccharide according to claim 8 or 9 in the preparation of drugs with uric acid-lowering, hypoglycemic, or anti-inflammatory activities.

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