Small molecule active peptides, compositions and their use in preparing products with antioxidant and hypoglycemic effects

Abstract

The present invention discloses small molecule active peptides, compositions and their use in preparing products with antioxidant and hypoglycemic effects, belonging to the technical field of bioactive peptides. The amino acid sequence of the small molecule active peptide of the present invention is at least one of DQFPR, LDQFPR and SYGLPR. The present invention separates and purifies a plurality of small molecule active peptides with antioxidant and hypoglycemic effects from peanut protein, chemically synthesizes the identified peptide sequences, and detects the antioxidant activity and hypoglycemic activity of the single peptide segment and the composite peptide segment of the synthetic peptide segment. The small molecule active peptide and its composite peptide segment both have good free radical scavenging and ɑ-glucosidase and ɑ-amylase inhibitory effects, and have good application prospects in the preparation of products with antioxidant and hypoglycemic effects, laying a foundation for the high added value utilization of peanut protein and the promotion of the research and 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 applications thereof in preparing products with antioxidant and blood sugar lowering effects. Background Art

[0002] Antioxidants are substances that can effectively inhibit free radical oxidation reactions. At present, most of the antioxidants used are chemically synthesized, such as L-ascorbic acid and its sodium salt, isoascorbic acid and its sodium salt. Blood sugar reduction mainly relies on drug intervention, such as glimepiride, metformin, acarbose, sitagliptin, repaglinide, etc. However, the safety of these chemical synthetic reagents and drugs is controversial, and the presence of chemical residues and toxic side effects cannot meet people's demand for the safety and sustainable development of health foods.

[0003] Although some natural functional proteins have antioxidant, hypoglycemic and anti-allergic effects, as biological macromolecules, most of these natural proteins have poor stability, are easily inactivated, and are not easily digested and absorbed by the human body. These characteristics limit their further application in the fields of food, health care and medicine. Compared with intact proteins, small molecule hydrolyzed peptides have high activity and small molecular weight and are more easily absorbed and utilized by the human body. Therefore, providing small molecule active peptides with antioxidant and hypoglycemic effects 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 a small molecule active peptide, a composition and the use thereof in the preparation of a product with antioxidant and hypoglycemic effects.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] 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.

[0007] The application of the above small molecule active peptides in the preparation of products with antioxidant and blood sugar lowering effects.

[0008] A small molecule active peptide composition, wherein the small molecule active peptide composition comprises at least one of the above-mentioned small molecule active peptides.

[0009] Based on the above scheme, the small molecule active peptide composition is any two of DQFPR, LDQFPR, and SYGLPR.

[0010] 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.

[0011] The application of the above small molecule active peptide composition in the preparation of products with antioxidant and blood sugar lowering effects.

[0012] Based on the above scheme, the antioxidant has the ability to scavenge free radicals.

[0013] Based on the above scheme, the free radical is at least one of DPPH and ABTS.

[0014] Based on the above scheme, the blood sugar lowering effect is to inhibit α-glucosidase and / or α-amylase.

[0015] On the basis of the above scheme, the product with antioxidant and blood sugar lowering effects is a medicine, and the medicine also contains pharmaceutically acceptable excipients.

[0016] The method for extracting small molecule active peptides with antioxidant and hypoglycemic effects from peanut protein comprises the following steps:

[0017] (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.

[0018] (2) After the enzymatic hydrolysis reaction is completed, the enzyme is inactivated and the enzymatic hydrolysis solution is centrifuged to retain the supernatant.

[0019] (3) The supernatant of the enzymatic hydrolysate 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.

[0020] (4) Take the enzymatic hydrolysate <3 kDa and determine the amino acid sequence by liquid chromatography-mass spectrometry;

[0021] (5) The Peptide Ranker program was used to predict the potential biological activity of the peptides in the peanut protein hydrolysate (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.

[0022] Based on the above scheme, the protease is at least one of neutral protease, alkaline protease, papain and trypsin; preferably, it is alkaline protease.

[0023] On the basis of the above scheme, the enzymatic hydrolysis conditions are: enzyme addition amount 0.5%-2%, enzymatic hydrolysis time 1h-3h, solid-liquid ratio 0.1-0.5; preferably, enzyme addition amount 1.25%, enzymatic hydrolysis time 2h, solid-liquid ratio 0.3.

[0024] Advantages of the technical solution of the present invention

[0025] The present invention separates and purifies a plurality of small molecule active peptides with antioxidant and hypoglycemic effects from peanut protein by using technologies such as enzymolysis and ultrafiltration, and preliminarily identifies its components and sequences by using liquid chromatography-mass spectrometry, peptide ranker and molecular docking technology. Chemical synthesis is performed according to the identified peptide sequence, and the antioxidant activity and hypoglycemic activity of the single peptide segment and the compound peptide segment of the synthetic peptide segment are tested. The small molecule active peptide and its compound peptide segment both have good free radical scavenging and α-glucosidase and α-amylase inhibition effects, and have good application prospects in the preparation of products with antioxidant and hypoglycemic effects, laying a foundation for the high added value utilization of peanut protein and the promotion of the research and development and application of functional active peptides. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The results of the free radical scavenging ability test of different molecular weight products obtained by alkaline protease hydrolysis of peanut protein;

[0027] Figure 2 The results of the inhibitory ability of α-glucosidase and α-amylase of the products with different molecular weights obtained by alkaline protease hydrolysis of peanut protein;

[0028] Figure 3 Secondary spectrum results of peanut protein peptide DQFPR;

[0029] Figure 4 Secondary spectrum results of peanut protein peptide LDQFPR;

[0030] Figure 5 Secondary spectrum results of peanut protein peptide SYGLPR;

[0031] Figure 6 The secondary structure prediction diagram of the peanut protein peptide DQFPR;

[0032] Figure 7 The secondary structure prediction diagram of the peanut protein peptide LDQFPR;

[0033] Figure 8 The predicted secondary structure of the peanut protein peptide SYGLPR;

[0034] Fig. 9 Molecular docking results of peanut active peptide sequence DQFPR and DPPH;

[0035] Fig.10 Molecular docking results of peanut active peptide sequence LDQFPR and DPPH;

[0036] Fig.11 Molecular docking results of peanut active peptide sequence SYGLPR and DPPH;

[0037] Fig.12 Molecular docking results of peanut active peptide sequence DQFPR and α-amylase;

[0038] Fig.13 Molecular docking results of peanut active peptide sequence LDQFPR and α-amylase;

[0039] Fig.14 Molecular docking results of peanut active peptide sequence SYGLPR and α-amylase;

[0040] Fig.15 Molecular weight plot of DQFPR mass spectra of small molecule active peptide sequences;

[0041] Fig.16 Molecular weight plot of the LDQFPR mass spectrum of the small molecule active peptide sequence;

[0042] Fig.17 Molecular weight plot of the mass spectrum of the small molecule active peptide sequence SYGLPR;

[0043] Fig.18 The results of free radical scavenging ability determination of chemically synthesized DQFPR, LDQFPR, and SYGLPR peptides;

[0044] Fig.19 The results of the determination of the α-glucosidase and α-amylase inhibitory abilities of the chemically synthesized DQFPR, LDQFPR, and SYGLPR peptides;

[0045] Fig. 20 Degree of hydrolysis of different peanut protein hydrolysates;

[0046] Fig.21 The results of the determination of the DPPH free radical scavenging ability of different peanut protein hydrolysates;

[0047] Fig. 22 The results of the determination of the inhibition rate of α-glucosidase by different peanut protein hydrolysates;

[0048] Fig.23 The results of free radical scavenging ability determination of the composite peptides DQFPR+LDQFPR, DQFPR+SYGLPR, and LDQFPR+SYGLPR;

[0049] Fig.24The results of the determination of the α-glucosidase and α-amylase inhibitory abilities of the complex peptides DQFPR+LDQFPR, DQFPR+SYGLPR, and LDQFPR+SYGLPR. DETAILED DESCRIPTION

[0050] The terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by those of ordinary skill in the art. The present invention will be further described in detail below in conjunction with specific examples and with reference to data. The following examples are intended to illustrate the present invention and are not intended to limit the scope of the present invention in any way.

[0051] 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 the field or according to the product instructions. The experimental materials, reagents, drugs, etc. used in the following examples, unless otherwise specified, can all be purchased through general channels.

[0052] The pH-Stat method was used to determine the hydrolysis of peanut protein. The specific method is as follows:

[0053] As protons are released during the hydrolysis of peanut protein, the pH value of the solution will drop sharply. At this time, 0.1M NaOH solution is added to maintain the pH. The degree of hydrolysis (DH) can be calculated by the volume of alkali solution added. The calculation formula is as follows:

[0054] DH=(h / h tot )×100%=[(C×V) / (a×m×h tot )]×100%

[0055] 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).

[0056] Determination of DPPH free radical scavenging ability

[0057] The peanut protein peptide solution was mixed with an equal volume of 0.1mmol / L DPPH ethanol solution, and reacted at room temperature in the dark for 30 minutes. The absorbance was measured at a wavelength of 517nm (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:

[0058] Clearance rate (%) = [(A control – A sample + A blank) / A control] × 100.

[0059] Determination of ABTS free radical scavenging ability:

[0060] Preparation of ABTS free radical solution: Mix equal volumes of 7 mM ABTS solution and 2.45 mM potassium persulfate at room temperature, react in the dark for 12-16 h, then dilute with anhydrous ethanol to an absorbance of 0.700±0.02 at 734 nm, and let stand for 30 min at room temperature before use. Use anhydrous ethanol as a reference solution. Mix 30 μL of sample (C sample) or distilled water (C blank) with 570 μL ABTS free radicals, react at room temperature in the dark for 10 min, and then detect the absorbance of the reaction solution at 734 nm. Calculate the ABTS free radical scavenging rate using the following formula:

[0061] ABTS free radical scavenging rate (%) = [(C blank - C sample) / C blank] × 100.

[0062] Determination of α-glucosidase inhibition rate

[0063] The experiment of peanut peptide inhibiting α-glucosidase activity was carried out using the method of Kim et al. with slight modifications.

[0064] 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. Then, the samples were preheated in a constant temperature water bath at 37 °C for 5 min, and 20 μL of α-glucosidase solution was immediately added to start the reaction. After mixing, the samples were incubated in a water bath at 37 °C for 30 min. After the reaction, 160 μL of 1M Na2CO3 solution was immediately added to terminate the reaction. The experiment also set up a blank group, a control group, and a sample background group. The blank group only added 100 μL of substrate pNPG, and the rest was replaced by an equal amount of buffer, eliminating the interference of the substrate pNPG spontaneously converted into the color-developing substance 4-nitrophenol (PNP) during the preheating process; the control group was the same as the experimental group except that the sample peptide solution was not added. The peptide solution was replaced by an equal amount of buffer, and the highest content of the color-developing substance PNP generated after the reaction of α-glucosidase and substrate pNPG was obtained under the same conditions; the sample background group only added the sample peptide solution, and the rest was replaced by an equal amount of distilled water, thus eliminating the influence of the absorbance value of the sample peptide solution at the corresponding wavelength. After the reaction was terminated, the content of the reactant PNP was detected at a wavelength of 405 nm by a spectrophotometer and recorded.

[0065] The calculation formula of α-glucosidase activity inhibition rate is:

[0066] α-glucosidase activity inhibition rate (%) = [OD c -(OD s -OD d )]×100 / (OD c -OD b )

[0067] OD b : The absorbance of the blank group, the absorbance of the peanut peptide solution and the α-glucosidase solution replaced by an equal amount of buffer;

[0068] OD c : Absorbance value of control group, absorbance value of solution in which peanut peptide solution was replaced by an equal amount of buffer;

[0069] OD s : absorbance value of experimental group;

[0070] OD d : Absorbance value of sample background group, absorbance value of solution containing only peanut peptide solution system.

[0071] Table 1 Determination of α-glucosidase activity inhibition rate

[0072]

[0073] Determination of α-amylase inhibition rate

[0074] The DNS colorimetric method (Table 2) was used to determine the α-amylase inhibitory activity of the samples. Soluble starch can be hydrolyzed to produce maltose under the catalytic action of α-amylase. Maltose, as a reducing sugar, can react with the DNS reagent to produce an orange-red product with maximum ultraviolet absorption at 540 nm. α-amylase was prepared into a 0.5 U / mL solution with PBS, and the concentration of the starch solution was 1%. In the experimental group, 50 μL peanut peptide solution and α-amylase solution (0.5 U / mL, 50 μL) were added in sequence, 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 at 37°C in a 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, and the rest of the operations were the same.

[0075] The calculation formula of α-amylase activity inhibition rate is as follows:

[0076] α-Amylase activity inhibition rate (%) = [OD A0 -(OD A1 -OD A2 ) / OD A0 ]×100

[0077] OD A0 : absorbance value of control group;

[0078] OD A1 : absorbance value of experimental group;

[0079] OD A2 : Absorbance value of sample background group.

[0080] Table 2 Determination of α-amylase activity inhibition rate

[0081]

[0082] The peanut protein used in the following examples was purchased from Zhenghong Biotechnology Co., Ltd.

[0083] Example 1

[0084] Small molecule active peptides, the small molecule active peptides comprising at least one peptide of the amino acid sequence shown in SEQ ID NO: 1 to SEQ ID NO: 3:

[0085] SEQ ID NO: 1: DQFPR;

[0086] SEQ ID NO:2: LDQFPR;

[0087] SEQ ID NO:3: SYGLPR.

[0088] Example 2

[0089] The method for extracting small molecule active peptides with antioxidant and hypoglycemic effects from peanut protein comprises the following steps:

[0090] (1) Dissolve peanut protein in distilled water at a ratio of 1:3 (w / v), heat at 90°C for 10 min for pre-denaturation, and add 1.25% alkaline protease for hydrolysis (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 hydrolysis temperature was 50°C, pH 10, and the hydrolysis time was 2 h.

[0091] (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.

[0092] (3) The supernatant of the enzymatic hydrolysate 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.

[0093] The free radical scavenging ability of components with different molecular weights was determined in relation to antioxidant activity and the inhibitory effect of α-glucosidase and α-amylase activities related to hypoglycemic activity. 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 ).

[0094] (4) The enzymatic hydrolysate <3 kDa was taken and the amino acid sequence was determined by liquid chromatography-mass spectrometry. The liquid phase was EasynLC 1200 nanoliter liquid phase system. The sample was desalted and retained on the pre-column and then separated by the analytical column. The analytical column specification was C18 reverse phase chromatography (Acclaim Pep Map RSLC, 75μm×25cmC18-2μm100A). The gradient used in the experiment was 5% to 38% of mobile phase B (80% acetonitrile, 0.1% formic acid) within 30 minutes. The mass spectrometer used the Thermo Fisher Q Exactive system (Thermo Fisher, USA) combined with the 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 scanning mode was in the information-dependent acquisition working mode (DDA, Data Dependent Analysis). The primary mass spectrometer scanning resolution was 70000, the scanning range was 350-2000 m / z, and the maximum injection time was 100 ms. A maximum of 20 secondary spectra with charges ranging from 2+ to 5+ were collected in each DDA cycle, and the maximum injection time for secondary mass spectrometry ions was 50 ms. The collision cell energy (high-energy collision-induced dissociation, HCD) was set to 28 eV for all precursor ions, and the dynamic exclusion was set to 25 s.

[0095] Through liquid chromatography-mass spectrometry technology, the results showed that a total of 1,610 peptides were obtained in the peanut peptide sample.

[0096] (5) The potential biological activity 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 peptides 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 ).

[0097] (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 molecular docking of the peanut polypeptide sequence with DPPH and α-amylase was performed using the Autodock Tools software to study the binding energy, hydrogen bonds and intermolecular forces between DPPH and α-amylase (receptors) and polypeptides (ligand molecules) (Table 3). The molecular docking results of the peanut polypeptide molecules DQFPR, LDQFPR, SYGLPR with DPPH and α-amylase were visualized using the Pymol software. The molecular docking results of the peanut polypeptide molecules DQFPR, LDQFPR, SYGLPR with DPPH and α-amylase are shown in Figure 3. Figure 9-11 As shown in Figure 2, the molecular docking results of peanut polypeptide molecules DQFPR, LDQFPR, SYGLPR and α-amylase are shown in Figure 2. Figure 12-14 As shown, three sequences were chemically synthesized ( Figure 15-17 ).

[0098] Table 3 Peanut polypeptide DQFPR, LDQFPR, SYGLPR information list

[0099]

[0100] The free radical scavenging ability and α-glucosidase and α-amylase inhibition of the synthesized peptides were verified by single peptides (2 mg / mL). The free radical scavenging ability and α-glucosidase and α-amylase inhibition effects were: SYGLPR>LDQFPR>DQFPR( Fig.18 , Fig.19 ).

[0101] Effects of different proteases on the hydrolysis degree, free radical scavenging ability related to antioxidant activity, and inhibition of α-glucosidase and α-amylase activities related to hypoglycemic activity of peanut protein hydrolysates

[0102] Neutral protease, alkaline protease, papain and trypsin were used to enzymolyze peanut protein. The temperature and pH of the enzymolysis were all at the optimal temperature and pH of each protease (Table 4). The other conditions were the same as those of alkaline protease. After the enzymolysis was completed, the effects of different proteases on the hydrolysis degree (DH,%), free radical scavenging ability related to antioxidant activity and the inhibitory effect of α-glucosidase activity related to hypoglycemic activity of the peanut protein hydrolysate were determined. The results are shown in Fig. 20 The results showed that alkaline protease had better hydrolysis ability ( Fig. 20 ), and the enzymatic hydrolysate has significant antioxidant and hypoglycemic effects ( Fig.21 , Fig. 22).

[0103] Table 4 Optimum temperature and optimum pH for different proteases

[0104]

[0105] Table 5 Effect of different enzymatic hydrolysis conditions on enzymatic hydrolysis effect

[0106]

[0107] On the basis of the single factor experiment, three factors, namely, enzyme dosage, enzymatic hydrolysis time and substrate concentration, were selected as the investigation factors. Design-Expert 13 was used to design three levels for each factor to conduct 17 groups of response surface experiments (Table 5). After the enzymatic hydrolysis was completed, the effects of different conditions on the degree of hydrolysis (DH,%), free radical scavenging ability related to antioxidant activity and the inhibitory effect of α-glucosidase and α-amylase activity related to hypoglycemic activity of peanut protein hydrolysate were determined. The results are shown in Table 5. The results showed that the hydrolysis time was 2 h, the enzyme dosage was 1.25%, and the material-liquid ratio was 0.3, the hydrolysis ability was good, and the antioxidant and hypoglycemic effects of the enzymatic hydrolysate were significant.

[0108] Example 3

[0109] The small molecule active peptide composition contains DQFPR and LDQFPR, wherein the mass ratio of DQFPR to LDQFPR is 1:1.

[0110] Example 4

[0111] The small molecule active peptide composition contains DQFPR and SYGLPR, wherein the mass ratio of DQFPR to SYGLPR is 1:1.

[0112] Example 5

[0113] The small molecule active peptide composition contains LDQFPR and SYGLPR, wherein the mass ratio of LDQFPR to SYGLPR is 1:1.

[0114] Application of small molecule active peptide composition in the preparation of products with antioxidant and hypoglycemic effects

[0115] The DQFPR, LDQFPR and SYGLPR peptides were compounded in pairs to obtain three compositions of DQFPR+LDQFPR, DQFPR+SYGLPR and LDQFPR+SYGLPR, in which the mass ratio of the two peptides 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.

[0116] The free radical scavenging ability and α-glucosidase and α-amylase inhibitory effects of the above-mentioned composite peptide fragments were determined.

[0117] The results showed that the peptides of DQFPR and SYGLPR had the best free radical scavenging ability and α-glucosidase and α-amylase inhibition effects after compounding, which was significantly better than the effects of DQFPR or SYGLPR alone ( Fig.23 , Fig.24 ).

[0118] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. Small molecule active peptide, characterized in that: The amino acid sequence of the small molecule active peptide is SYGLPR.

2. The use of small molecule active peptides in the preparation of products with antioxidant and hypoglycemic effects, characterized in that: The amino acid sequence of the small molecule active peptide is at least one of DQFPR, LDQFPR and SYGLPR.

3. A small molecule active peptide composition, characterized in that: The small molecule active peptide composition is a combination of SYGLPR and DQFPR, or a combination of SYGLPR and LDQFPR.

4. According to the small molecule active peptide composition of claim 3, the mass ratio of the two small molecule active peptides in the small molecule active peptide composition is 1:

1.

5. Use of the small molecule active peptide composition according to any one of claims 3 to 4 in the preparation of a product with antioxidant and hypoglycemic effects.

6. The use of the small molecule active peptide composition according to claim 5 in preparing a product with antioxidant and hypoglycemic effects, characterized in that: The antioxidant has the ability to remove free radicals.

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 free radical is at least one of DPPH and ABTS.

8. The use of the small molecule active peptide composition according to claim 5 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.

9. The use of the small molecule active peptide composition according to claim 5 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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