Small-molecule active peptide, composition and application of small-molecule active peptide in preparation of product with antioxidant and hypoglycemic effects

Abstract

The invention discloses a small-molecule active peptide, a composition and application of the small-molecule active peptide in preparation of a product with antioxidant and hypoglycemic effects, and belongs to the technical field of biological active peptides. The amino acid sequence of the small molecule active peptide is at least one of DQFPR, LDQFPR and SYGLPR. According to the invention, a plurality of small molecule active peptides with antioxidant and hypoglycemic effects are obtained by separating and purifying peanut protein, the identified peptide fragment sequence is chemically synthesized, and the antioxidant activity and hypoglycemic activity of a single peptide fragment and a compound peptide fragment of the synthesized peptide fragment are detected. The small molecule active peptide and the compound peptide fragment thereof have good effects of scavenging free radicals and inhibiting alpha-glucosidase and alpha-amylase, and have good application prospects in preparation of products with antioxidant and hypoglycemic effects; and a foundation is laid for high-added-value utilization of the peanut protein and promotion of research, development and application of functional active peptides.

Description

Technical Field

[0001] The present invention belongs to the technical field of bioactive peptides, and specifically relates to small molecule active peptides, compositions and their application in preparing products with antioxidant and blood sugar-lowering effects. Background Art

[0002] Antioxidants are substances that effectively inhibit free radical oxidation reactions. Currently, most of the antioxidants used are chemically synthesized, such as L-ascorbic acid and its sodium salt, and erythorbic acid and its sodium salt. Blood sugar reduction relies primarily on drug interventions, such as glimepiride, metformin, acarbose, sitagliptin, and repaglinide. However, the safety of these chemically synthesized reagents and drugs is controversial, and the presence of chemical residues and toxic side effects fails to meet the demand for safe and sustainable health food products.

[0003] While some natural functional proteins possess antioxidant, hypoglycemic, and anti-allergic properties, as biomacromolecules, these natural proteins are generally unstable, easily inactivated, and difficult to digest and absorb by the human body. These characteristics limit their further application in the food, healthcare, and pharmaceutical fields. Compared to intact proteins, small molecule hydrolyzed peptides have higher activity and smaller molecular weight, making them more easily absorbed and utilized by the human body. Therefore, providing small molecule active peptides with antioxidant and hypoglycemic properties is of great significance for the development of antioxidant and hypoglycemic products. Summary of the Invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide small molecule active peptides, compositions and their use in preparing products with antioxidant and hypoglycemic effects.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A small molecule active peptide, wherein the amino acid sequence of the small molecule active peptide is at least one of DQFPR, LDQFPR, and SYGLPR.

[0006] The application of the above-mentioned small molecule active peptides in the preparation of products with antioxidant and blood sugar-lowering effects.

[0007] A small molecule active peptide composition comprising at least one of the above-mentioned small molecule active peptides.

[0008] Based on the above scheme, the small molecule active peptide composition is any two of DQFPR, LDQFPR, and SYGLPR.

[0009] Based on the above scheme, the mass ratio of the two small molecule active peptides in the small molecule active peptide composition is 1:1.

[0010] The application of the above-mentioned small molecule active peptide composition in the preparation of products with antioxidant and blood sugar-lowering effects.

[0011] Based on the above solution, the antioxidant has the ability to scavenge free radicals.

[0012] Based on the above solution, the free radical is at least one of DPPH and ABTS.

[0013] Based on the above scheme, the blood sugar lowering effect is to inhibit α-glucosidase and / or α-amylase.

[0014] On the basis of the above scheme, the product with antioxidant and blood sugar-lowering effects is a medicine, and the medicine further contains pharmaceutically acceptable excipients.

[0015] The method for extracting small molecule active peptides with antioxidant and hypoglycemic effects from peanut protein comprises the following steps: (1) Add distilled water to the peanut protein to dissolve it, heat it at 90℃ for 10 min to pre-denature it, and add protease for enzymatic hydrolysis.

[0016] (2) After the enzymatic hydrolysis reaction is completed, the enzyme is inactivated, and the enzymatic hydrolysis solution is centrifuged to retain the supernatant.

[0017] (3) The supernatant of the enzymatic hydrolysis product was fractionated into different molecular weights using an ultrafiltration centrifuge tube with a molecular weight cutoff of 10 kDa and 3 kDa. The fractions were collected as follows: >10 kDa, the peptide was retained but did not pass through the 10 kDa membrane; 10 kDa, the peptide permeated the 10 kDa membrane but not the 3 kDa membrane; <3 kDa, the peptide permeated the 3 kDa membrane. Thus, the enzymatic hydrolysate with a molecular weight range of <3 kDa, 3-10 kDa, and >10 kDa was obtained.

[0018] (4) Take the enzymatic hydrolysate of <3 kDa and determine the amino acid sequence by liquid chromatography-mass spectrometry; (5) Use the Peptide Ranker program to predict the potential biological activity of the peptides in the peanut protein hydrolysate (0-1), select peptides with a score >0.5, and use the ToxinPred3.0 website to select peptides with a toxicity threshold prediction of <0.4.

[0019] Based on the above scheme, the protease is at least one of neutral protease, alkaline protease, papain, and trypsin; preferably, it is alkaline protease.

[0020] Based on the above scheme, the enzymatic hydrolysis conditions are: enzyme addition amount 0.5%-2%, enzymatic hydrolysis time 1h-3h, and material-liquid ratio 0.1-0.5; preferably, enzyme addition amount 1.25%, enzymatic hydrolysis time 2h, and material-liquid ratio 0.3.

[0021] Advantages of the technical solution of the present invention The present invention uses enzymatic hydrolysis, ultrafiltration, and other techniques to isolate and purify multiple small-molecule active peptides with antioxidant and hypoglycemic efficacy from peanut protein. Their components and sequences are then preliminarily identified using liquid chromatography-mass spectrometry, peptide ranker, and molecular docking techniques. Chemical synthesis is performed based on the identified peptide sequences, and the antioxidant and hypoglycemic activities of the synthesized peptides, both single and combined, are tested. The small-molecule active peptides and their combined peptides demonstrate excellent free radical scavenging and α-glucosidase and α-amylase inhibition properties, demonstrating promising application prospects in the preparation of products with antioxidant and hypoglycemic efficacy. This approach lays the foundation for the high-value-added utilization of peanut protein and for promoting the research, development, and application of functional active peptides. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Determination of the free radical scavenging ability of products of different molecular weights obtained by alkaline protease hydrolysis of peanut protein; Figure 2 The results of the inhibitory ability of α-glucosidase and α-amylase of products with different molecular weights obtained by alkaline protease hydrolysis of peanut protein; Figure 3 Secondary spectrum results of peanut protein peptide DQFPR; Figure 4 Secondary spectrum results of peanut protein peptide LDQFPR; Figure 5 Secondary spectrum results of peanut protein peptide SYGLPR; Figure 6 The predicted secondary structure of the peanut protein peptide DQFPR; Figure 7 The secondary structure prediction diagram of peanut protein peptide LDQFPR; Figure 8 The predicted secondary structure of the peanut protein peptide SYGLPR; Figure 9 Molecular docking results of peanut active peptide sequence DQFPR and DPPH; Figure 10 Molecular docking results of peanut active peptide sequence LDQFPR and DPPH; Figure 11 Molecular docking results of peanut active peptide sequence SYGLPR and DPPH; Figure 12 Molecular docking results of peanut active peptide sequence DQFPR and α-amylase; Figure 13 Molecular docking results of peanut active peptide sequence LDQFPR and α-amylase; Figure 14 Molecular docking results of peanut active peptide sequence SYGLPR and α-amylase; Figure 15 Molecular weight plot of DQFPR mass spectra of small molecule active peptide sequences; Figure 16 Molecular weight plot of the mass spectrum of the small molecule active peptide sequence LDQFPR; Figure 17 Molecular weight plot of the mass spectrum of the small molecule active peptide sequence SYGLPR; Figure 18 The results of free radical scavenging ability determination of chemically synthesized DQFPR, LDQFPR, and SYGLPR peptides; Figure 19 The results of the α-glucosidase and α-amylase inhibitory activities of chemically synthesized DQFPR, LDQFPR, and SYGLPR peptides; Figure 20 Degree of hydrolysis of different peanut protein hydrolysates; Figure 21 Determination of the DPPH free radical scavenging ability of different peanut protein hydrolysates; Figure 22 Determination of the inhibition rate of α-glucosidase by different peanut protein hydrolysates; Figure 23 The results of free radical scavenging ability determination of the composite peptides DQFPR+LDQFPR, DQFPR+SYGLPR, and LDQFPR+SYGLPR; Figure 24 The results of the inhibitory ability of the complex peptides DQFPR+LDQFPR, DQFPR+SYGLPR, and LDQFPR+SYGLPR against α-glucosidase and α-amylase. DETAILED DESCRIPTION

[0023] The terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by those of ordinary skill in the art. Below, in conjunction with specific examples, the present invention will be further described in detail with reference to data. The following examples are merely for illustration of the present invention and are not intended to limit the scope of the present invention in any way.

[0024] The experimental methods in the following examples, unless otherwise specified, are all conventional methods and are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. The experimental materials, reagents, and drugs used in the following examples, unless otherwise specified, can all be purchased through general channels.

[0025] The pH-Stat method was used to determine the hydrolysis of peanut protein. The specific method is as follows: During the hydrolysis of peanut protein, as protons are released, the pH value of the solution drops sharply. At this time, 0.1M NaOH solution is added to maintain the pH. The degree of hydrolysis (DH) can be calculated based on the volume of alkali solution added. The calculation formula is as follows: DH=(h / h tot )×100%=[(C×V) / (a×m×h tot )]×100% Where: C, concentration of NaOH solution, moL / L; V, volume of NaOH solution consumed, mL; a, degree of dissociation of α-amino group; a=10 pH-pKa / (1+10 pH-pKa ), where pH is the pH of the hydrolysis system, pKa is the pKa of the amino group, pKa = 7.8 + [(298-T) × 2400] / (298 × T), where T is the Kelvin temperature; m, the mass of peanut protein in the solution, g; h tot , the total number of peptide bonds in the substrate protein, mmol / g, for peanut protein h tot =7.13 (calculated based on the amino acid composition of peanut protein).

[0026] Determination of DPPH free radical scavenging ability Peanut protein peptide solution was mixed with an equal volume of 0.1 mmol / L DPPH ethanol solution and reacted at room temperature in the dark for 30 min. The absorbance was measured at a wavelength of 517 nm (A sample). The corresponding absorbance was measured by replacing the DPPH ethanol solution with an equal amount of ethanol (A blank). The corresponding absorbance was measured by replacing the peanut protein peptide solution with an equal amount of distilled water (A control). The DPPH free radical scavenging rate was calculated using the following formula: Clearance rate (%) = [(A control – A sample + A blank) / A control] × 100.

[0027] Determination of ABTS free radical scavenging ability: Preparation of ABTS radical solution: Mix equal volumes of 7 mM ABTS solution and 2.45 mM potassium persulfate at room temperature in the dark for 12-16 hours. Then dilute with anhydrous ethanol to an absorbance of 0.700 ± 0.02 at 734 nm. Let stand at room temperature for 30 minutes before use. Use anhydrous ethanol as a reference solution. Mix 30 μL of sample (C sample) or distilled water (C blank) with 570 μL of ABTS radicals. Incubate at room temperature in the dark for 10 minutes. Measure the absorbance of the reaction solution at 734 nm. Calculate the ABTS radical scavenging rate using the following formula: ABTS free radical scavenging rate (%) = [(C blank - C sample) / C blank] × 100.

[0028] Determination of α-glucosidase inhibition rate The peanut peptide inhibition experiment of α-glucosidase activity was carried out using the method of Kim et al. with slight modifications.

[0029] α-glucosidase and p-nitrophenyl-α-D-glucoside (pNPG) were prepared into 0.2 U / mL and 1 mg / mL solutions, respectively, using 0.2 M sodium phosphate buffer, pH 6.8. 100 μL of buffer, 100 μL of pNPG, and 100 μL of sample peptide solution were added to the experimental groups, respectively. The samples were then preheated in a 37°C constant temperature water bath for 5 min. After removal, 20 μL of α-glucosidase solution was immediately added to initiate the reaction. After mixing, the samples were incubated in a 37°C water bath for 30 min. The reaction was terminated by adding 160 μL of 1M Na2CO3 solution. The experiment included blank, control, and sample background groups. The blank group added only 100 μL of the substrate pNPG, with the remainder replaced by an equal volume of buffer. This eliminated interference from the spontaneous conversion of pNPG to the chromogenic product 4-nitrophenol (PNP) during the preheating process. The control group was identical to the experimental group except that the sample peptide solution was omitted. The peptide solution was replaced by an equal volume of buffer. Under the same conditions, the maximum content of the chromogenic product PNP generated by the reaction between α-glucosidase and the substrate pNPG was determined. The sample background group added only the sample peptide solution, with the remainder replaced by an equal volume of distilled water. This eliminated the influence of the sample peptide solution's absorbance at the corresponding wavelength. After the reaction was terminated, the PNP content was measured and recorded using a spectrophotometer at 405 nm.

[0030] The calculation formula of α-glucosidase activity inhibition rate is: α-glucosidase activity inhibition rate (%) = [OD c -(OD s -OD d )]×100 / (OD c -OD b ) OD b : absorbance of blank group, absorbance of peanut peptide solution and α-glucosidase solution replaced by equal amount of buffer; OD c : absorbance value of the control group, absorbance value of the solution in which the peanut peptide solution was replaced by an equal amount of buffer; OD s : absorbance value of experimental group; OD d : Absorbance value of sample background group, absorbance value of solution containing only peanut peptide solution system.

[0031] Table 1 Determination of α-glucosidase activity inhibition rate

[0032] Determination of α-amylase inhibition rate The α-amylase inhibitory activity of the samples was determined using the DNS colorimetric method (Table 2). Soluble starch can be hydrolyzed to maltose under the catalytic action of α-amylase. Maltose, a reducing sugar, reacts with the DNS reagent to produce an orange-red product with a maximum UV absorption at 540 nm. α-amylase was prepared in PBS to a 0.5 U / mL solution, and the starch solution concentration was 1%. The experimental group was sequentially added with 50 μL peanut peptide solution and α-amylase solution (0.5 U / mL, 50 μL), preheated at 37°C for 10 min, and substrate soluble starch solution (1%, 50 μL) was added to start the reaction. The reaction was incubated in a 37°C water bath for 15 min. Immediately after the reaction, 100 μL DNS reagent was added to develop color in a boiling water bath for 5 min to terminate the reaction. After cooling to room temperature, 250 μL double-distilled water was added, and the absorbance was measured at 540 nm. A control group and a sample background group were also set up in the experiment. The control group was the experimental group with 50 μL peanut peptide solution replaced with 50 μL buffer; the sample background group was the experimental group with 50 μL starch solution replaced with 50 μL buffer. The rest of the operations were the same.

[0033] The calculation formula for the inhibition rate of α-amylase activity is as follows: α-amylase activity inhibition rate (%) = [OD A0 -(OD A1 -OD A2 ) / OD A0 ]×100 OD A0 : absorbance value of control group; OD A1 : absorbance value of experimental group; OD A2 : Absorbance value of sample background group.

[0034] Table 2 Determination of α-amylase activity inhibition rate

[0035] The peanut protein used in the following examples was purchased from Zhenghong Biotechnology Co., Ltd.

[0036] Example 1 Small molecule active peptides, the small molecule active peptides comprising a peptide having an amino acid sequence of at least one of SEQ ID NO: 1 to SEQ ID NO: 3: SEQ ID NO: 1: DQFPR; SEQ ID NO: 2: LDQFPR; SEQ ID NO: 3: SYGLPR.

[0037] Example 2 The method for extracting small molecule active peptides with antioxidant and hypoglycemic effects from peanut protein comprises the following steps: (1) Peanut protein was dissolved in distilled water at a ratio of 1:3 (w / v), heated at 90°C for 10 min for pre-denaturation, and hydrolyzed by adding 1.25% alkaline protease (5 g protein powder was dissolved in 16.6 mL water, and the amount of enzyme added was 1.25% of the substrate peanut protein). The enzymatic hydrolysis temperature was 50°C, pH 10, and the enzymatic hydrolysis time was 2 h.

[0038] (2) After the enzymatic hydrolysis reaction is completed, the enzymatic hydrolyzate is inactivated at 90°C for 15 min to terminate the reaction. The enzymatic hydrolyzate is then centrifuged at 4000 r / min and 4°C for 20 min, and the supernatant is retained.

[0039] (3) The supernatant of the enzymatic hydrolysis product was fractionated into different molecular weights using an ultrafiltration centrifuge tube with a molecular weight cutoff of 10 kDa and 3 kDa. The fractions were collected as follows: >10 kDa, the peptide was retained but did not pass through the 10 kDa membrane; 10 kDa, the peptide permeated the 10 kDa membrane but not the 3 kDa membrane; <3 kDa, the peptide permeated the 3 kDa membrane. Thus, the enzymatic hydrolysate with a molecular weight range of <3 kDa, 3-10 kDa, and >10 kDa was obtained.

[0040] The free radical scavenging ability of components with different molecular weights, which is related to antioxidant activity, and the inhibitory effect of α-glucosidase and α-amylase activities, which is related to hypoglycemic activity, were determined. The results showed that protein peptides with a smaller molecular weight <3 KDa showed better effects in scavenging free radicals and inhibiting α-glucosidase and α-amylase ( Figure 1 、 Figure 2 ).

[0041] (4) The amino acid sequence of the enzyme hydrolysate <3 kDa was determined by liquid chromatography-mass spectrometry (LC-MS / MS). The sample was desalted and retained on a pre-column using an Easyn LC 1200 nanoliter system and then separated on an analytical column. The analytical column specifications were C18 reversed-phase chromatography (Acclaim Pep Map RSLC, 75 μm × 25 cm C18-2 μm 100A). The gradient used in the experiment was from 5% to 38% mobile phase B (80% acetonitrile, 0.1% formic acid) over 30 min. The mass spectrometer was a Thermo Fisher Q Exactive system (Thermo Fisher, USA) combined with a nanospray NanoFlex ion source (Thermo Fisher, USA). The spray voltage was 1.9 kV and the ion transfer tube heating temperature was 275 °C. The mass spectrometer scan mode was data-dependent analysis (DDA). The primary mass spectrometer scan resolution was 70,000, the scan range was 350-2000 m / z, and the maximum injection time was 100 ms. A maximum of 20 MS spectra with charges ranging from 2+ to 5+ were acquired per DDA cycle, with a maximum injection time of 50 ms. The collision cell energy (high-energy collision-induced dissociation, HCD) was set to 28 eV for all precursor ions, and dynamic exclusion was set to 25 s.

[0042] Through liquid chromatography-mass spectrometry technology, the results showed that a total of 1,610 peptides were obtained in the peanut peptide sample.

[0043] (5) The potential bioactivity of the peptides in the peanut protein hydrolysate was predicted using the Peptide Ranker program (0-1), and peptides with a score > 0.5 were selected. The ToxinPred3.0 website was used to select peptides with a toxicity threshold prediction of < 0.4, and finally 3 peptides were obtained. The secondary mass spectrometry analysis showed that the peptide had a molecular weight of 661.3184 and a sequence of DQFPR ( Figure 3 ); a peptide with a molecular weight of 774.4024 and a sequence of LDQFPR ( Figure 4 ); a peptide with a molecular weight of 691.3653 and a sequence of SYGLPR ( Figure 5 ), the specific information is shown in Table 3. The secondary structures of peanut peptides DQFPR, LDQFPR, and SYGLPR were predicted by PepDraw software ( Figure 6 、 Figure 7 、 Figure 8 ).

[0044] (6) The 3D structures of DPPH (PubChem CID 2735032) and α-amylase (PDB ID: 1UA7) were obtained from the PubChem database and the Protein Data Bank (PDB) database, respectively. The Autodock Tools software was used to perform molecular docking of the peanut polypeptide sequence with DPPH and α-amylase, and the binding energy, hydrogen bond, and intermolecular force between DPPH and α-amylase (receptors) and polypeptides (ligand molecules) were studied (Table 3). The molecular docking results of the peanut polypeptide molecules DQFPR, LDQFPR, and SYGLPR with DPPH and α-amylase were visualized using Pymol software. The molecular docking results of the peanut polypeptide molecules DQFPR, LDQFPR, and SYGLPR with DPPH are shown in Figure 3. Figures 9-11 As shown in the figure, the molecular docking results of peanut polypeptide molecules DQFPR, LDQFPR, SYGLPR and α-amylase are shown in the figure. Figure 12-14 As shown, three sequences were chemically synthesized ( Figure 15-17 ).

[0045] Table 3 Information of peanut peptides DQFPR, LDQFPR and SYGLPR

[0046] The free radical scavenging ability and α-glucosidase and α-amylase inhibitory effects of the synthesized peptides were verified by single peptide fragments (2 mg / mL). The results of free radical scavenging ability and α-glucosidase and α-amylase inhibitory effects were as follows: SYGLPR>LDQFPR>DQFPR( Figure 18 、 Figure 19 ).

[0047] Effects of different proteases on the hydrolysis degree, free radical scavenging capacity related to antioxidant activity, and inhibitory effects of α-glucosidase and α-amylase activities related to hypoglycemic activity of peanut protein hydrolysates Peanut protein was enzymatically hydrolyzed using neutral protease, alkaline protease, papain, and trypsin. The hydrolysis temperature and pH were all within the optimal temperature and pH range for each protease (Table 4). Other conditions were the same as for alkaline protease. After enzymatic hydrolysis, the effects of different proteases on the degree of hydrolysis (DH,%), free radical scavenging capacity related to antioxidant activity, and inhibitory effect of α-glucosidase activity related to hypoglycemic activity of the peanut protein hydrolyzed products were determined. Figure 20 The results showed that alkaline protease had a better hydrolysis ability ( Figure 20 ), and the enzymatic hydrolysis products have significant antioxidant and hypoglycemic effects ( Figure 21 、 Figure 22 ).

[0048] Table 4 Optimum temperature and optimum pH of different proteases

[0049] Table 5 Effects of different enzymatic hydrolysis conditions on enzymatic hydrolysis results

[0050] Based on the single-factor experiments, three factors (enzyme dosage, enzymatic hydrolysis time, and substrate concentration) were selected as the experimental factors. Using Design-Expert 13, three levels were designed for each factor, and 17 response surface experiments were conducted (Table 5). After enzymatic hydrolysis, the effects of different conditions on the degree of hydrolysis (DH), free radical scavenging capacity related to antioxidant activity, and the inhibitory effects of α-glucosidase and α-amylase activities related to hypoglycemic activity of the peanut enzymatic hydrolysates were determined. The results are shown in Table 5. The results show that an enzymatic hydrolysis time of 2 h, an enzyme dosage of 1.25%, and a material-to-liquid ratio of 0.3 resulted in good hydrolysis capacity and significant antioxidant and hypoglycemic efficacy of the enzymatic hydrolysates.

[0051] Example 3 The small molecule active peptide composition contains DQFPR and LDQFPR, wherein the mass ratio of DQFPR to LDQFPR is 1:1.

[0052] Example 4 The small molecule active peptide composition contains DQFPR and SYGLPR, wherein the mass ratio of DQFPR to SYGLPR is 1:1.

[0053] Example 5 The small molecule active peptide composition contains LDQFPR and SYGLPR, wherein the mass ratio of LDQFPR to SYGLPR is 1:1.

[0054] Application of small molecule active peptide composition in the preparation of products with antioxidant and hypoglycemic effects The DQFPR, LDQFPR, and SYGLPR peptides were compounded in pairs to obtain three compositions: DQFPR+LDQFPR, DQFPR+SYGLPR, and LDQFPR+SYGLPR. The mass ratio of the two peptides in the composition was 1:1. Ultrapure water was used as a solvent to dissolve the peptides so that the concentration of each peptide was 2 mg / mL.

[0055] The free radical scavenging ability and α-glucosidase and α-amylase inhibitory effects of the above-mentioned composite peptide were determined.

[0056] The results showed that the combination of DQFPR and SYGLPR peptides had the best free radical scavenging ability and α-glucosidase and α-amylase inhibitory effects, which were significantly better than the effects of DQFPR or SYGLPR alone ( Figure 23 、 Figure 24 ).

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention remain within the scope of protection of the present invention.

Claims

1. Small molecule active peptide, characterized in that: The amino acid sequence of the small molecule active peptide is at least one of DQFPR, LDQFPR and SYGLPR.

2. Use of the small molecule active peptide according to claim 1 in the preparation of products with antioxidant and hypoglycemic effects.

3. A small molecule active peptide composition, characterized in that: The small molecule active peptide composition comprises at least one of the small molecule active peptides described in claim 1.

4. The small molecule active peptide composition according to claim 3, characterized in that: The small molecule active peptide composition is any two of DQFPR, LDQFPR and SYGLPR.

5. The small molecule active peptide composition according to claim 4, characterized in that: The mass ratio of the two small molecule active peptides in the small molecule active peptide composition is 1:

1.

6. Use of the small molecule active peptide composition according to any one of claims 3 to 5 in the preparation of a product with antioxidant and hypoglycemic effects.

7. The use of the small molecule active peptide composition according to claim 6 in preparing a product with antioxidant and hypoglycemic effects, characterized in that: The antioxidant has the ability to remove free radicals.

8. The use of the small molecule active peptide composition according to claim 7 in preparing a product with antioxidant and hypoglycemic effects, characterized in that: The free radical is at least one of DPPH and ABTS.

9. The use of the small molecule active peptide composition according to claim 6 in preparing a product with antioxidant and hypoglycemic effects, characterized in that: The blood sugar lowering effect is to inhibit α-glucosidase and / or α-amylase.

10. The use of the small molecule active peptide composition according to claim 6 in preparing a product with antioxidant and hypoglycemic effects, characterized in that: The product with antioxidant and blood sugar lowering effects is a medicine, and the medicine also contains pharmaceutically acceptable excipients.

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