Quinoa hexapeptide with hypoglycemic effect and application thereof

Abstract

The application discloses a quinoa hexapeptide with a blood sugar lowering effect and application thereof, and belongs to the technical field of bioactive peptides. The amino acid sequence of the quinoa hexapeptide PGSPGR is Pro-Gly-Ser-Pro-Gly-Arg. The quinoa hexapeptide PGSPGR has alpha-glucosidase inhibitory activity and can effectively reduce blood sugar level, and therefore, can be applied to preparation of medicines or food for lowering blood sugar. The application further provides a polypeptide containing the peptide segment PGSPGR and a quinoa peptide rich in the polypeptide, and the polypeptide and the quinoa peptide are applied to preparation of medicines or food for lowering blood sugar, thereby providing a new scheme and theoretical basis for treatment of diabetes, and having good market prospect and application potential.

Description

Technical Field

[0001] This invention belongs to the field of bioactive peptide technology, specifically relating to a quinoa hexapeptide with hypoglycemic effect and its application. Background Technology

[0002] Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycemia, caused by insulin secretion defects and / or impaired biological action. Type 2 diabetes mellitus (T2DM) accounts for more than 90% of all cases, and its core pathological mechanisms involve insulin resistance and progressive decline in pancreatic β-cell function. Persistent hyperglycemia can lead to a variety of serious complications, such as cardiovascular disease, nephropathy, retinopathy, and neuropathy, placing a heavy burden on global public health systems.

[0003] Currently, there are various clinical strategies for lowering blood glucose, among which alpha-glucosidase inhibitors are one of the key targets for controlling postprandial blood glucose (PPBG). Alpha-glucosidase, located at the brush border of the small intestine, is a key digestive enzyme in the human body responsible for further breaking down oligosaccharides (such as maltose and sucrose) into absorbable monosaccharides (glucose). By inhibiting the activity of alpha-glucosidase, the final digestion of carbohydrates and the rate of glucose absorption can be slowed down, thereby effectively "smoothing out peaks and troughs" and stabilizing the postprandial blood glucose curve. Oral hypoglycemic agents such as metformin and miglitol, as well as alpha-glucosidase inhibitors, are widely used in clinical practice. However, these synthetic inhibitors are often accompanied by side effects such as gastrointestinal bloating and diarrhea, affecting patient compliance. Therefore, finding highly effective and low-toxicity alpha-glucosidase inhibitors from natural sources has become an important direction for the research and development of health foods and drugs.

[0004] Among numerous natural sources, food-derived bioactive peptides have attracted considerable attention due to their high activity, low toxicity, good absorption, and biocompatibility. Numerous studies have confirmed that specific peptides released from soybean, milk protein, marine organisms, and cereal proteins through enzymatic hydrolysis possess significant α-glucosidase inhibitory activity. These peptides bind to the active sites of enzymes through specific amino acid sequences, achieving competitive or non-competitive inhibition. Quinoa, as a nutritionally complete "super grain," has a protein with a balanced amino acid composition and is easily hydrolyzed. Existing research indicates that quinoa protein hydrolysates and their isolated peptides possess various biological activities, including a potential hypoglycemic effect, the mechanism of which may involve the inhibition of key digestive enzymes such as α-glucosidase. This provides a solid scientific basis for the targeted discovery of novel α-glucosidase inhibitory peptides from quinoa protein.

[0005] While screening for bioactive peptides from natural products is the mainstream strategy, current research largely focuses on complex proteolytic hydrolysates or mixed peptides, with insufficient identification of key functional peptides (especially the precise sequences acting on α-glucosidase). This leads to unstable product activity, unclear mechanisms, and difficulties in standardized application. Therefore, the precise identification, synthesis, and validation of the smallest active units (such as hexapeptides) with definite α-glucosidase inhibitory activity from quinoa peptides are of great significance for developing next-generation hypoglycemic functional ingredients or drug lead compounds with clear targets and fewer side effects.

[0006] Based on the above background, the present invention aims to overcome the shortcomings of the prior art. Summary of the Invention

[0007] Technical Problem to be Solved: To address the aforementioned problems, the purpose of this invention is to provide a quinoa hexapeptide with hypoglycemic effects and its applications. This invention utilizes papain, neutral protease, and flavor protease to enzymatically hydrolyze black quinoa protein powder to obtain quinoa peptides. LC-MS / MS peptide mapping analysis was used to resolve the polypeptide sequence of the quinoa peptides, revealing that they are rich in the PGSPGR peptide segment (amino acid sequence Pro-Gly-Ser-Pro-Gly-Arg). The quinoa hexapeptide PGSPGR has α-glucosidase inhibitory activity, effectively lowering blood sugar levels without significant side effects. Therefore, it can be applied to the preparation of drugs for hypoglycemia or health foods that help maintain healthy blood sugar levels.

[0008] Technical solution: A quinoa hexapeptide, wherein the amino acid sequence of the quinoa hexapeptide is Pro-Gly-Ser-Pro-Gly-Arg (PGSPGR).

[0009] Furthermore, the preparation methods of the quinoa hexapeptide include enzymatic hydrolysis, solid-phase synthesis, or genetic engineering.

[0010] Furthermore, the solid-phase synthesis method employs the Fmoc solid-phase synthesis strategy, using Fmoc-protected amino acids as raw materials and Wang resin as a solid-phase carrier. Arginine, glycine, proline, serine, glycine, and proline residues are introduced sequentially to extend the peptide chain from the C-terminus to the N-terminus, thereby synthesizing the hexapeptide PGSPGR in a solid phase.

[0011] Furthermore, the quinoa hexapeptide has a hypoglycemic effect.

[0012] The present invention also provides a quinoa peptide with hypoglycemic effect, comprising the above-mentioned quinoa hexapeptide PGSPGR.

[0013] The present invention also provides a method for preparing the above-mentioned quinoa peptides, comprising the following steps:

[0014] S1. Mix black quinoa protein powder and water at a mass ratio of 1:(18-22), and adjust the pH to 7.0±0.2;

[0015] S2. Add 0.45-0.55% papain, 0.45-0.55% neutral protease and 0.45-0.55% flavor protease by weight of black quinoa protein powder and hydrolyze for 4.5-5.5 h.

[0016] S3. After the enzymatic hydrolysis is completed, inactivate the enzyme at 100 ℃ for 10 min, centrifuge at 5500-6500 r / min for 20 min, and collect the supernatant.

[0017] S4. Quinoa peptides are obtained after freeze-drying.

[0018] Furthermore, the enzyme activities of the papain, neutral protease, and flavor protease are 200 U / mg, 150 U / mg, and 60 U / mg, respectively.

[0019] The present invention also provides a composition comprising the above-mentioned quinoa hexapeptide or quinoa peptide.

[0020] Furthermore, the quinoa hexapeptide PGSPGR or quinoa peptides containing PGSPGR in the composition can be used as the sole active ingredient to exert a hypoglycemic effect, or they can be combined with other active ingredients that have a hypoglycemic effect.

[0021] The present invention also provides a drug with a hypoglycemic effect, the drug comprising the above-mentioned quinoa hexapeptide, quinoa peptide or a combination thereof.

[0022] The present invention also provides a health food that helps maintain healthy blood sugar levels, wherein the drug comprises the above-mentioned quinoa hexapeptide, quinoa peptide or a combination thereof.

[0023] Furthermore, the drug is a drug for the prevention or treatment of diabetes.

[0024] Furthermore, the diabetes is type 2 diabetes.

[0025] Furthermore, the drug also contains a pharmaceutically acceptable carrier.

[0026] Furthermore, the pharmaceutically acceptable carrier is any formulation or carrier medium capable of delivering an effective dose of the active substance of the present invention without interfering with the biological activity of the active substance and without toxic side effects on the host or subject.

[0027] Furthermore, the pharmaceutically acceptable carrier includes one or more of the following: fillers, wetting agents, disintegrants, binders, or lubricants.

[0028] Furthermore, the formulation of the drug may be, but is not limited to, an oral formulation.

[0029] Furthermore, the formulation of the drug may be, but is not limited to, oral liquid, capsule, microcapsule powder, tablet, granule or emulsion.

[0030] Furthermore, the dosage form of the health food that helps maintain healthy blood sugar levels is a beverage, oral liquid, capsule, microcapsule powder, tablet, granule, or emulsion.

[0031] The present invention also provides the use of the above-mentioned quinoa hexapeptide, quinoa peptide or combination in the preparation of hypoglycemic drugs.

[0032] The present invention also provides the use of the above-mentioned quinoa hexapeptide, quinoa peptide or composition in the preparation of health food products that help maintain healthy blood sugar levels.

[0033] Beneficial effects:

[0034] 1. This invention is the first to accurately identify and obtain a quinoa hexapeptide PGSPGR (Pro-Gly-Ser-Pro-Gly-Arg) with definite hypoglycemic activity from black quinoa protein. This peptide fragment showed no breakage after simulated gastrointestinal digestion and exhibited good in vivo stability. At the same time, molecular docking technology confirmed that this hexapeptide has a high binding energy with α-glucosidase and can effectively inhibit enzyme activity through various intermolecular interactions. The target and molecular mechanism of its hypoglycemic action were clarified, laying a solid theoretical foundation for subsequent standardized development.

[0035] 2. This invention establishes an efficient preparation process for black quinoa peptides. Using black quinoa protein powder as raw material, the process involves enzymatic hydrolysis with papain, neutral protease, and flavor protease. After enzyme inactivation, centrifugation, and freeze-drying, quinoa peptides rich in PGSPGR are obtained. The process is simple, the conditions are mild, and it is easy to scale up industrially. Moreover, quinoa is a natural grain with a wide range of sources and controllable costs.

[0036] 3. The quinoa hexapeptide PGSPGR of the present invention has been verified by both in vitro and in vivo experiments, showing significant hypoglycemic activity with no obvious side effects: In in vitro experiments, the hexapeptide inhibited α-glucosidase by 63% at a concentration of 0.1 mg / mL, and its inhibitory activity was significantly better than that of the similar quinoa hexapeptide LGPPGA; In in vivo experiments on a hyperglycemic zebrafish model, its hypoglycemic effect was better than that of metformin, a commonly used clinical hypoglycemic drug, and at an effective concentration, it could restore the blood glucose level of the hyperglycemic model organism to normal levels, providing a novel natural active ingredient for the treatment of type 2 diabetes.

[0037] 4. The quinoa hexapeptide PGSPGR, quinoa peptides rich in this peptide, and their compositions of the present invention have a wide range of applications. They can be used alone as hypoglycemic active ingredients or combined with other hypoglycemic active ingredients to prepare drugs for the prevention / treatment of type 2 diabetes or health foods that help maintain healthy blood sugar levels. The formulations can cover various types such as oral liquids, capsules, tablets, and granules to meet different application needs.

[0038] 5. Compared to existing clinical synthetic hypoglycemic drugs that easily cause side effects such as gastrointestinal bloating and diarrhea, the quinoa hexapeptide of this invention is a food-derived bioactive peptide that combines high activity, low toxicity, good biocompatibility and absorption, resulting in higher patient compliance. At the same time, it solves the industry pain points of existing natural hypoglycemic peptide research, which mostly focuses on mixed enzymatic hydrolysates, unclear active ingredients, and unstable product quality. It realizes the precise and standardized development of natural hypoglycemic peptides and has extremely high industrialization value and market application potential. Attached Figure Description

[0039] Figure 1 This is the secondary mass spectrum of quinoa hexapeptide PGSPGR in Example 2;

[0040] Figure 2 This is a schematic diagram illustrating the binding interaction between quinoa hexapeptide PGSPGR and α-glucosidase in Example 2.

[0041] Figure 3 The in vitro α-glucosidase inhibition rate of quinoa hexapeptides PGSPGR and LGPPGA in Example 3;

[0042] Figure 4 The hypoglycemic effect of quinoa hexapeptide PGSPGR in a hyperglycemic zebrafish model in Example 4;

[0043] Figure 5 This is a comparison of the hypoglycemic effects of quinoa hexapeptide PGSPGR and LGPPGA in a hyperglycemic zebrafish model in Example 5. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In the present invention, unless otherwise specified, the equipment and raw materials used can be purchased from the market or are commonly used in the art. Unless otherwise specified, the methods in the following embodiments are conventional methods in the art.

[0045] Black quinoa protein was purchased from Ningbo Herbes Health Technology Co., Ltd.; papain was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with an enzyme activity of 200 U / mg; neutral protease (derived from Bacillus subtilis) was purchased from Nanning Pangbo Bioengineering Co., Ltd., with an enzyme activity of 150 U / mg; and flavor protease was purchased from Angel Enzyme Preparations (Yichang) Co., Ltd., with an enzyme activity of 60 U / mg.

[0046] Example 1

[0047] The preparation method of quinoa peptides includes the following steps:

[0048] S1. Mix black quinoa protein powder and water at a mass ratio of 1:20, and adjust the pH to 7.0;

[0049] S2. Add 0.5% papain, 0.5% neutral protease and 0.5% flavor protease by weight of black quinoa protein powder, and enzymatically hydrolyze them together at 50℃ for 5 h.

[0050] S3. After the enzymatic hydrolysis is completed, inactivate the enzyme at 100 ℃ for 10 min, centrifuge at 6000 r / min for 20 min, and collect the supernatant.

[0051] S4. Quinoa peptides are obtained after freeze-drying.

[0052] Example 2 Screening of active peptides

[0053] In this embodiment, the peptide segments of quinoa peptide were identified by LC-MS / MS, and the specific mechanism of action between quinoa peptide and α-glucosidase was explored using molecular docking technology. Highly efficient α-glucosidase inhibitory peptides were also screened.

[0054] 1. LC-MS / MS peptide profiling analysis

[0055] Peptide sequencing analysis of quinoa peptide samples was performed using LC-MS / MS. A C18 reversed-phase column with a pore size of 300 Å, a specification of 100 mm × 2.1 mm, and a particle size of 1.7 μm was used. Separation was performed at a flow rate of 0.3 mL / min at a column temperature of 40 ℃. Mobile phase A was an aqueous solution containing 0.1% (v / v) formic acid, and mobile phase B was an acetonitrile solution containing 0.1% (v / v) formic acid. A Thermo Fisher Q Exactive high-resolution tandem mass spectrometer was used for full scan and MS2 scans in positive ionization mode. Full scan mode mass spectrometry conditions: scan range: 200-2000 m / z, resolution: 70000; MS2 mode mass spectrometry conditions: collision voltage: 30 V, resolution: 17500. Raw mass spectrometry data (raw files) were obtained and then compared with protein databases to complete the identification and analysis of quinoa peptide sequences.

[0056] Analysis of quinoa peptides revealed that they contain hexapeptides PGSPGR and LGPPGA, as shown in Table 1.

[0057] Table 1. Mass spectrometry results of hexapeptide PGSPGR and LGPPGA in quinoa

[0058] peptide sequence length Mass-to-charge ratio (m / z) Molecular weight (Da) PGSPGR 6 570.30 570 LGPPGA 6 511.29 511

[0059] The secondary mass spectrum of the hexapeptide PGSPGR is shown below. Figure 1 As shown, the fragment ions of peptides include: N-terminal fragment ions (types a, b, and c) and C-terminal fragment ions (types x, y, and z). The side chains of type a, y, and z ions break to form type d, v, and w ions, respectively. In addition, there are internal ions formed by breakage at both ends, with the b and y series ions being the most common. The primary structure of the peptide can be deduced based on the b or y series fragment ions, and the molecular weight is 570 Da. Further secondary mass spectrometry analysis of the hexapeptide using source collision-induced dissociation technology confirmed the primary structure of the hexapeptide to be Pro-Gly-Ser-Pro-Gly-Arg.

[0060] 2. Molecular docking

[0061] To discover bioactive peptides with hypoglycemic potential, this study screened them based on their ability to inhibit α-glucosidase. α-glucosidase is mainly located on the brush border membrane of small intestinal epithelial cells. α-glucosidase inhibitors can bind to these inhibitors without being absorbed by the small intestine, thereby rapidly inhibiting carbohydrate hydrolysis and achieving a hypoglycemic effect. Based on this mechanism, the study conducted computer-aided screening of small peptides from quinoa that may interact with α-glucosidase.

[0062] The following criteria were set during the screening process: mass spectrometry peak intensity greater than 1×10⁻⁶. 3 The PeptideRanker prediction score exceeded 0.6. Subsequently, molecular docking simulations were performed using the α-glucosidase crystal structure (number 5ZCE) obtained from the PDB database, employing Discovery Studio software. The specific procedure included: pretreating the receptor protein by removing water molecules and adding hydrogen atoms to clarify its active site region; and constructing a small peptide structure conforming to the lowest energy conformation as a ligand. The CDOCKER method was used for docking, evaluating the binding mode, action site, and key amino acid residues between the ligand and receptor, and ranking the results based on binding free energy and the number of hydrogen bonds.

[0063] Two hexapeptides with superior binding properties were finally selected: PGSPGR and LGPPGA. Specific information is summarized in Table 2.

[0064] Table 2. Peptides in quinoa peptides with potential hypoglycemic activity

[0065] peptide sequence PeptideRanker score Docking energy (kcal / mol) PGSPGR 0.73 -57.31 LGPPGA 0.60 -49.41

[0066] Molecular docking 2D and 3D diagrams of quinoa hexapeptide PGSPGR with α-glucosidase are shown below. Figure 2 As shown. Analysis of the chemical bonds revealed that the hexapeptide PGSPGR mainly binds to α-glucosidase through van der Waals forces, hydrogen bonds (including conventional hydrogen bonds and carbon-hydrogen bonds), and electrostatic interactions (salt bridges, attracting charges, and π-cations), with a docking energy of -57.31 kcal / mol. α-glucosidase forms 17 van der Waals forces with amino acid residues THR409, GLY410, MET385, ILE143, PHE225, PHE163, HIS103, GLN167, ARG415, HIS326, GLU283, ALA200, ARG197, PHE144, GLY259, MET229, and LYS334; 12 hydrogen bonds with ARG411, ASP60, PHE282, GLN256, ASN258, TRP288, GLY286, MET285, and GLN328; and 5 electrostatic interactions with ASP60, TYR63, ASP199, and ASP327. Molecular docking results show that the hexapeptide PGSPGR can bind to α-glucosidase, thereby inhibiting α-glucosidase and exerting a hypoglycemic effect.

[0067] 3. Artificially synthesized peptides

[0068] We commissioned Jier Biochemical (Shanghai) Co., Ltd. to synthesize peptides PGSPGR and LGPPGA with a purity of ≥98% for subsequent functional verification.

[0069] Example 3: In vitro α-glucosidase inhibition rate of quinoa hexapeptides PGSPGR and LGPPGA

[0070] Quinoa hexapeptide PGSPGR (PR6) and LGPPGA (LA6) solutions at concentrations of 0.005, 0.01, 0.02, 0.05, and 0.1 mg / mL were prepared using PBS. The inhibition rates of hexapeptide PR6 and LA6 on α-glucosidase were determined. 25 µL of each concentration of hexapeptide PR6 and LA6 solution was mixed with 5 U / mL α-glucosidase, and then 25 µL of PBS solution was added to each well of a 96-well plate. The plate was incubated at 37 °C for 30 min. Then, 25 µL of 3 mM PNPG solution was added to each well and mixed thoroughly. The plate was incubated at 37 °C for 30 min. Finally, 150 µL of 0.1 M Na₂CO₃ solution was added to each well to terminate the reaction, and the absorbance was immediately measured at 405 nm. The inhibition rate was calculated using the following formula:

[0071]

[0072] In the formula, A1 and As represent the absorbance of the control group (25µL α-glucosidase + 25µL PNPG + 50µL PBS) and the sample group (25µL α-glucosidase + 25µL PNPG + 25µL samples of different concentrations + 25µL PBS), respectively. A0 and Ab represent the absorbance of the blank control group (25µL PNPG + 75µL PBS) and the blank control group (25µL PNPG + 25µL samples of different concentrations + 50µL PBS), respectively.

[0073] Experimental results are as follows Figure 3 As shown in the results, at concentrations of 0.01–0.1 mg / mL, the α-glucosidase inhibition rate of PR6 was significantly higher than that of LA6, and the inhibition rate reached as high as 63% at a concentration of 0.1 mg / mL. α-Glucosidase is a key digestive enzyme that breaks down oligosaccharides (such as maltose and sucrose) in food into monosaccharides (glucose). Inhibition of its activity slows down and delays the digestion and absorption of carbohydrates, thereby reducing the rate of glucose release and absorption, helping to smooth out peak and trough increases in postprandial blood glucose. Therefore, α-glucosidase inhibitors are considered to have the potential to lower blood glucose. These experimental results demonstrate that PR6 has a strong glucosidase inhibitory ability, indicating its potential to lower blood glucose.

[0074] Example 4: Hypoglycemic effect of quinoa hexapeptide PGSPGR in a hyperglycemic zebrafish model

[0075] The hypoglycemic effect of hexapeptide PGSPGR was determined using a hyperglycemic zebrafish model. Wild-caught AB strain 4-day-old zebrafish were placed in six-well plates, with 3 parallel wells per group and 10 zebrafish per well. The intervention groups were as follows:

[0076] (1) Blank control group (NC): system water;

[0077] (2) Model group (MC): 333 μM alloxan + 2.67% glucose + system water;

[0078] (3) Metformin positive control group (PC): 333 μM alloxan + 2.67% glucose + 5 μg / mL metformin + system water;

[0079] (4) Quinoa hexapeptide PGSPGR intervention group (PR6-10, PR6-5, PR6-1, PR6-0.1): 333 μM alloxan + 2.67% glucose + 10 / 5 / 1 / 0.1 μg / mL hexapeptide PGSPGR + system water.

[0080] Four-day-old zebrafish were treated according to the above intervention protocol for 24 h. They were then washed three times with PBS solution to remove the sugar solution from their surface. Using a disposable dropper, the zebrafish from the six-well plate were transferred to 1.5 mL centrifuge tubes. Excess liquid was removed, and 0.1 mL of anhydrous ethanol was added. After being placed in a cool place for 15 min, the tubes were placed in an oven (60℃) for 120 min until dried (crushed). Finally, 5 µL of ultrapure water was added to the centrifuge tubes, and the mixture was sonicated for 10 min. 2 µL of the mixture was then used to measure the glucose level using a glucometer.

[0081] The results are as follows Figure 4 As shown, compared with the blank control group (NC group), the blood glucose level of the model control group (MC group) after 24 h of modeling with 333 μM alloxan + 2.67% glucose was significantly increased (p < 0.0001), indicating that the hyperglycemia model was successfully established. After intervention with the positive control drug 5 μg / mL metformin (PC group), there was a significant downregulation effect compared with the MC group (p < 0.001). Under intervention with hexapeptide PGSPGR at concentrations of 10 μg / mL, 5 μg / mL and 1 μg / mL, blood glucose levels were significantly downregulated compared with the MC group (p < 0.0001), and the downregulation was not significantly different from the NC group (p > 0.05), indicating that quinoa hexapeptide PGSPGR has a significant hypoglycemic effect, and its effect is even better than that of metformin.

[0082] Example 5: Comparison of the hypoglycemic effects of hexapeptide PGSPGR and LGPPGA in a hyperglycemic zebrafish model.

[0083] The hypoglycemic effects of hexapeptides PGSPGR and LGPPGA were compared using a hyperglycemic zebrafish model. Wild-caught AB strain 4-day-old zebrafish were placed in six-well plates, with 3 parallel wells per group and 10 zebrafish per well, as follows:

[0084] (1) Blank control group (NC): system water;

[0085] (2) Model group (MC): 333 μM alloxan + 2.67% glucose + system water;

[0086] (3) Quinoa hexapeptide PGSPGR intervention group (PR6): 333 μM alloxan + 2.67% glucose + 1 μg / mL hexapeptide PGSPGR + system water;

[0087] (4) Quinoa hexapeptide LGPPGA intervention group (LA6): 333 μM alloxan + 2.67% glucose + 1 μg / mL hexapeptide LGPPGA + system water.

[0088] The intervention method and blood glucose measurement method were the same as those used in "The hypoglycemic effect of hexapeptide PGSPGR in a hyperglycemic zebrafish model". Results were as follows: Figure 5 As shown, under the intervention of quinoa hexapeptide PGSPGR and LGPPGA at a concentration of 1 μg / mL, compared with the model control MC group, quinoa hexapeptide PGSPGR significantly downregulated blood glucose levels (p<0.01), while quinoa hexapeptide LGPPGA had no significant downregulation effect (p>0.05).

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall still fall within the scope of protection of the present invention.

Claims

1. A quinoa hexapeptide, characterized in that, The amino acid sequence of the quinoa hexapeptide is Pro-Gly-Ser-Pro-Gly-Arg.

2. The quinoa hexapeptide according to claim 1, characterized in that: The preparation methods of the quinoa hexapeptide include enzymatic hydrolysis, solid-phase synthesis, or genetic engineering.

3. The quinoa hexapeptide according to claim 1 or 2, characterized in that: The quinoa hexapeptide has a hypoglycemic effect.

4. A quinoa peptide with hypoglycemic effect, characterized in that, The quinoa peptide with hypoglycemic effect includes the quinoa hexapeptide described in claim 1.

5. A composition, characterized in that, The composition comprises the quinoa hexapeptide of claim 1 or the quinoa peptide of claim 4.

6. A drug with hypoglycemic effect, characterized in that, The drug comprises the quinoa hexapeptide of claim 1, the quinoa peptide of claim 4, or the composition of claim 5.

7. A health food product that helps maintain healthy blood sugar levels, characterized in that, The health food contains the quinoa hexapeptide of claim 1, the quinoa peptide of claim 4, or the composition of claim 5.

8. The drug according to claim 6, characterized in that, The drug is a medication for the prevention or treatment of diabetes.

9. The medicament according to claim 8, characterized in that, The diabetes mentioned is type 2 diabetes.

10. The medicament according to claim 6, characterized in that, The drug also contains a pharmaceutically acceptable carrier.

11. The use of the quinoa hexapeptide of claim 1, the quinoa peptide of claim 4, or the composition of claim 5 in the preparation of a hypoglycemic drug.

12. The use of the quinoa hexapeptide of claim 1, the quinoa peptide of claim 4, or the composition of claim 5 in the preparation of health foods that help maintain healthy blood sugar levels.

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