Chenopodium quinoa active peptide with antioxidant and neuroprotective effects, preparation and application thereof

Abstract

This invention discloses quinoa bioactive peptides, formulations, and applications with antioxidant and neuroprotective effects, belonging to the field of bioactive peptide technology. The amino acid sequence of the quinoa bioactive peptides described in this invention is at least one of FDDGPFF and LFGGF. Using natural quinoa as raw material, this invention isolates and purifies two quinoa bioactive peptides with antioxidant and neuroprotective effects. Testing showed that both single and complex peptide segments of these two quinoa bioactive peptides exhibit good antioxidant effects and can exert neuroprotective and cognitive-improving effects through multiple targets; providing a core material basis and solid technical support for the development of products with antioxidant and neuroprotective effects.

Description

Technical Field

[0001] This invention belongs to the field of bioactive peptide technology, specifically relating to quinoa bioactive peptides, preparations, and applications with antioxidant and neuroprotective effects. Background Technology

[0002] With the aging population and changing lifestyles, the incidence of neurodegenerative diseases such as Alzheimer's and Parkinson's is rising year by year, becoming a major global public health problem. These diseases are often accompanied by oxidative stress and neuronal damage, but currently used clinical treatments often have problems such as significant side effects, limited efficacy, or high cost. Therefore, developing safe, effective, and naturally derived neuroprotective agents is of great practical significance.

[0003] Bioactive peptides have attracted much attention in the development of functional foods and drugs due to their small molecular weight, easy absorption, high safety, and strong targeting properties. Plant-derived bioactive peptides have gradually become a research hotspot in recent years, especially peptide components contained in some traditional grains or emerging superfoods, which exhibit a variety of physiological activities such as antioxidation, anti-inflammation, blood pressure reduction, and immune regulation.

[0004] Quinoa, a nutritionally complete pseudo-cereal, is rich in high-quality protein with a balanced amino acid composition, especially rich in essential amino acids such as lysine, making it an ideal raw material for the preparation of bioactive peptides. Current research indicates that quinoa protein, after enzymatic hydrolysis, can yield peptides with antioxidant and blood pressure-lowering activities; however, research on its neuroprotective effects remains limited. In particular, systematic studies on the extraction of quinoa sprouts and their effects on nerve cell protection and cognitive function improvement have not yet been reported.

[0005] On the other hand, current research on neuroprotective bioactive peptides mainly focuses on animal proteins (such as milk proteins and fish proteins) or a few plant proteins (such as soybeans and wheat), while there is insufficient exploration of the protein resources of quinoa sprouts, a product of a specific physiological stage. In addition, the activity of single peptides in existing technologies is often limited, and research on achieving synergistic effects through peptide combinations is still in its early stages.

[0006] Therefore, there is an urgent need in this field to develop a peptide component derived from natural plants with clear antioxidant and neuroprotective activities, and to further explore its combined applications, in order to provide a safe, effective and easily industrialized neuroprotective product. Summary of the Invention

[0007] In view of the problems existing in the prior art, the purpose of this invention is to provide quinoa active peptides, preparations and their applications with antioxidant and neuroprotective effects.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] Quinoa bioactive peptides with antioxidant and neuroprotective effects, wherein the amino acid sequence of the quinoa bioactive peptides is at least one of FDDGPFF and LFGGF.

[0010] The above-mentioned quinoa active peptides with antioxidant and neuroprotective effects are used in the preparation of products with antioxidant and neuroprotective effects.

[0011] Based on the above scheme, the product is food, medicine or health product.

[0012] Based on the above scheme, the product further includes excipients acceptable for food, pharmaceutical or health products.

[0013] Based on the above scheme, the antioxidant is characterized by DPPH free radical and ABTS free radical scavenging effects and FRAP antioxidant activity.

[0014] Based on the above scheme, the neuroprotective effect is to reduce glutamate-induced neuronal cell damage and improve cell survival rate.

[0015] Based on the above scheme, the neuroprotective effect is to improve cognitive dysfunction, including improving spatial learning ability and enhancing memory retention ability.

[0016] Based on the above scheme, the neuroprotective effect is achieved by increasing the level of brain-derived neurotrophic factor in the brain and enhancing the antioxidant capacity of brain tissue.

[0017] An anti-oxidative and neuroprotective agent, the active ingredient being at least one of FDDGPFF and LFGGF.

[0018] Based on the above scheme, the concentration of the active ingredient is 0.5~1 mg / mL.

[0019] Advantages of the technical solution of this invention:

[0020] This invention uses natural quinoa as raw material to separate and purify two quinoa bioactive peptides, FDDGPFF and LFGGF, which have antioxidant and neuroprotective effects. The test results showed that both the single peptide fragments and the complex peptide fragments of these two quinoa bioactive peptides have good antioxidant effects, and can exert neuroprotective and cognitive improvement effects through multiple targets. This provides a core material basis and solid technical support for the development of products with antioxidant and neuroprotective effects. Attached Figure Description

[0021] Figure 1 This is the mass spectrum of the FDDGPFF peptide.

[0022] Figure 2 This is the mass spectrum of the LFGGF peptide.

[0023] Figure 3 Survival rate of SH-SY5Y cells treated with a single peptide FDDGPFF(A);

[0024] Figure 4 Survival rate of SH-SY5Y cells treated with a single peptide LFGGF(B);

[0025] Figure 5 Survival rate of SH-SY5Y cells treated with the complex peptide FDDGPFF(A) + LFGGF(B);

[0026] Figure 6 Results of staining for live and dead cells;

[0027] Figure 7 Determination of the in vitro antioxidant activity of quinoa active peptides;

[0028] Figure 8 Results of molecular weight distribution determination of quinoa protein peptides;

[0029] Figure 9 The proportion of components with different molecular weight ranges in quinoa mixed peptides;

[0030] Figure 10 The movement trajectories of mice in different groups in the Morris water maze experiment. The red squares represent the positions where the mice were placed in the water, the blue squares represent the positions where the mice last stopped, and the red circles in the first quadrant represent the original positions before the circular platform was removed.

[0031] Figure 11 Swimming distance, escape latency, number of steps taken, and quadrant ratio of mice in the Morris water maze experiment;

[0032] Figure 12 Changes in superoxide dismutase (SOD) activity in mouse serum after treatment with quinoa mixed peptides;

[0033] Figure 13 Changes in malondialdehyde (MDA) levels in mouse serum after treatment with quinoa mixed peptides;

[0034] Figure 14 Changes in glutathione peroxidase (GSH-Px) levels in mice after treatment with quinoa mixed peptides;

[0035] Figure 15 Levels of brain-derived neurotrophic factor in the brains of mice in each group;

[0036] Figure 16 HE staining results of histopathological sections of the hippocampus and its subregions (CA1, CA3, DG) of mice from different groups;

[0037] Figure 17 Changes in body weight of mice in each group during drug administration.

[0038] In the above figures, lowercase letters are used to indicate the significance of differences between multiple groups. The same lowercase letter indicates that the difference between groups is not significant (P > 0.05); different lowercase letters indicate that the difference between groups is significant (P < 0.05).

[0039] In the above figures, * indicates a significant difference between groups (usually P < 0.05), ** indicates an extremely significant difference (usually P < 0.01), *** indicates a very significant difference (usually P < 0.001), and **** indicates an extremely high significance level of P < 0.0001. Detailed Implementation

[0040] The terminology used in this invention, unless otherwise specified, generally has the meanings commonly understood by those skilled in the art. The invention is further described in detail below with reference to specific embodiments and data. The following embodiments are merely illustrative and are not intended to limit the scope of the invention in any way.

[0041] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the experimental materials, reagents, and chemicals used in the following embodiments can be obtained through general channels.

[0042] The quinoa used in the following examples was purchased from RT-Mart in Chengyang, China (produced in Qinghai).

[0043] The complex protease used in the following examples is Novozymes Protamex 1.6, batch number: PW2A1231, with an alkaline and neutral protease complex activity of 1.6 AU-N / g.

[0044] In the following embodiments,

[0045] 1. Method for determining DPPH free radical scavenging activity

[0046] Prepare a 0.1 mM DPPH ethanol solution. Add 2.4 mL of 0.2 mM DPPH to the control tube and sample tube, respectively. Add 2.4 mL of anhydrous ethanol to the reference tube. Add 0.5 mL of sample to each of the sample and reference tubes. Top up each tube to 4 mL with the sample extraction reagent. Mix all tubes thoroughly and let them react in the dark for 30 min. Then measure the absorbance at 517 nm.

[0047] Table 1. Reagents added to each tube

[0048]

[0049] Calculate the DPPH clearance rate using the following formula:

[0050]

[0051] Note: 0.1mM DPPH reagent: Accurately weigh 19.7 mg of DPPH reagent and dilute to 500 mL with anhydrous ethanol. Protect from light and store at 4°C.

[0052] 2. Determination of ABTS free radical scavenging rate

[0053] Prepare the ABTS stock solution by adding 179 μL of 140 mM potassium persulfate solution to 10 mL of 7 mM ABTS aqueous solution and incubating for 14 hours in a dark room at room temperature. Dilute 300 μL of the ABTS stock solution to 10 mL with distilled water to obtain the ABTS working solution. Add 170 μL of the ABTS working solution to an ELISA plate, then add 20 μL of 1 mg / mL peptide solution or complex peptide solution and mix thoroughly. Incubate at 37°C with shaking for 10 min, and measure the absorbance A at 734 nm. i Deionized water was used as a blank control, and its absorbance was recorded as A0.

[0054] The ABTS radical scavenging rate is calculated using the following formula:

[0055]

[0056] 3. FRAP antioxidant activity assay

[0057] Weigh 408.2 mg of sodium acetate trihydrate and dissolve it in 10 mL of distilled water to obtain solution 1; weigh 6.2 mg of TPTZ and dissolve it in 3 mL of distilled water and 80 μL of HCl to obtain solution 2; weigh 6.5 mg of anhydrous ferric chloride and dissolve it in 2 mL of distilled water to obtain solution 3. Mix solutions 1, 2, and 3 in a ratio of 10:1:1 to obtain FRAP solution for later use.

[0058] 27.8 mg of FeSO4·7H2O was dissolved in 10 mL of distilled water to obtain a 10 mM mixed solution, which was then diluted to 0.4 mM, 0.5 mM, 1.0 mM, 1.6 mM, 2 mM, and 2.5 mM to prepare standard curves. 6.25 μL each of the standard curves and the sample were added to 18.75 μL of distilled water, followed by 187.5 μL of FRAP solution. The mixture was thoroughly mixed and incubated at 37 °C in the dark for 30 min. The absorbance was measured at 593 nm. Each sample was measured in triplicate. Results are expressed as Trolox.

[0059] Example 1

[0060] The steps for extracting quinoa bioactive peptides from quinoa sprouts are as follows:

[0061] 1. Raw material pretreatment: Quinoa sprouts that have germinated for 4 days are dried and pulverized. Quinoa protein is then extracted using the alkali dissolution and acid precipitation method in the existing technology (Ma Hongxin, Yuan Zhihao, Liu Honghai, et al. Comparison of different methods for extracting quinoa protein [J]. Journal of Food Safety and Quality Inspection, 2021, 12(05):1890-1898.DOI:10.19812 / j.cnki.jfsq11-5956 / ts.2021.05.044.).

[0062] 2. Enzymatic hydrolysis: Quinoa protein was prepared into a 2% (w / v) aqueous solution and preheated at 90°C for 10 minutes to denature it. After cooling, 0.15% (by weight of substrate) of a complex protease was added, and enzymatic hydrolysis was carried out at pH 7.5 and 50°C for 4 hours. During the enzymatic hydrolysis, the mixture was continuously stirred and the pH was maintained constant with 0.1 M NaOH.

[0063] 3. Separation and purification: The enzyme hydrolysate was inactivated at 90℃ for 15 minutes, cooled, and centrifuged to collect the supernatant. The supernatant was filtered sequentially through 0.45μm and 0.22μm filter membranes, and then separated using an ultrafiltration membrane with a molecular weight cutoff of 3 kDa. The permeate with a molecular weight <3 kDa was collected, freeze-dried, and the quinoa mixed peptide fraction was obtained and named HDP.

[0064] 4. Peptide Identification: High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS / MS) was used to analyze HDP. First, the HDP sample was desalted using a C18 desalting column (GL Science, Inc., Sigma, St. Louis, Missouri, USA), dried under vacuum at 45°C, and then redissolved in ultrapure water. Second, LC-MS / MS analysis was performed on a thermoelectric EASY-nLC 1200 (Thermo Scientific, P / N LC140) equipped with a C18 column (Acclaim PepMap C18, 75 μm × 25 cm), in conjunction with an Orbitrap Exploris 480 (Thermo Scientific, P / N BRE725533). 5 μL of sample was injected at a flow rate of 600 nL / min, with an electrospray voltage of 2 kV and a column temperature of 55°C. 0.1% formic acid aqueous solution was used as mobile phase A, and 0.1% formic acid acetonitrile was used as mobile phase B. The chromatographic gradient was as follows: 0–66 min, 4–95% B. The mass spectrometer was operated in data-dependent acquisition mode and automatically switched between MS and MS / MS modes. The parameter settings were as follows: (1) MS: scan range (m / z) = 100–1500; resolution = 70000; maximum injection time of automatic gain control = 50 ms; AGC target = 5 × 10 5 (2) HCD-MS / MS: Resolution = 17500; Scan range (m / z) = 100–2000; Maximum injection time = 100; AGC target = 2 × 10 5 Collision energy = 30%.

[0065] 5. Database retrieval and bioinformatics analysis

[0066] Search criteria: PEAKS searches the target protein database using raw mass spectrometry files. Search parameters are as follows:

[0067] 1) Fixed modifications: Calbamidomethyl (C).

[0068] 2) Variable modifications: Oxidation (M), Acetyl (Peptide N-term).

[0069] 3) Enzyme: Non specific.

[0070] 4) Database: uniprotkb_proteome_UP000596660_2025_01_07.fasta.

[0071] 5) Peptide Mass Tolerance: 20 ppm

[0072] 6) Secondary mass spectrometry bias (Fragment Mass Tolerance): 0.02 Da.

[0073] Through database retrieval and bioinformatics analysis (including Peptide Ranker activity prediction and ToxinPred toxicity prediction), characteristic peptides with high activity scores (>0.5) and low toxicity (<0.4) were screened, and two peptide sequences were finally obtained, namely FDDGPFF and LFGGF.

[0074] 6. The binding affinity between the peptide and the target protein was determined through molecular docking. The X-ray crystal structure of the protein KEAP1 (PDB code: 5FNQ) was retrieved from the protein database (www.rcsb.org). The three-dimensional structure of the peptide and energy minimization were constructed in ChemBio3D Ultra 14.0. Ligand, acceptor, and docking parameters were completed using AutoDock Tools. The docking parameters and docking treatments were applied using AutoDock Vina to predict the affinity of the peptide for KEAP1, expressed as a Vina score (kcal / mol). PyMol 1.7 was used for molecular visualization and analysis.

[0075] Results: The affinity of FDDGPFF was -10.9 kcal / mol; the affinity of LFGGF was -10.4 kcal / mol.

[0076] Two peptides were synthesized using a chemical synthesis method, with a chemical synthesis purity of 95%. Their mass spectra are shown below. Figure 1 and Figure 2 As shown.

[0077] Example 2

[0078] A quinoa bioactive peptide with antioxidant and neuroprotective effects, wherein the amino acid sequence of the bioactive peptide is shown in SEQ ID NO:1 or SEQ ID NO:2.

[0079] SEQ ID NO:1: FDDGPFF;

[0080] SEQ ID NO:2: LFGGF.

[0081] Example 3

[0082] In vitro neuroprotective effect of quinoa bioactive peptides (cell assay)

[0083] The direct neuroprotective effects of quinoa active peptides and their combinations were verified using a glutamate-induced human neuroblastoma SH-SY5Y cell injury model.

[0084] (1) Cytotoxicity test (CCK-8 assay)

[0085] SH-SY5Y cells were planted at a density of 1×10⁶ cells per well. 4 Cells were seeded at a density of [number] cells per well in 96-well plates. After 24 hours of culture and adherence, cells were divided into three groups: a control group (CK), a glutamate group (Glu, 8 mM), and experimental groups supplemented with different concentrations (50 μM, 100 μM, 200 μM) of single peptides FDDGPFF (A), LFGGF (B), and their 1:1 mass ratio combination (A+B) on a glutamate-damaged substrate. A separate group (CK+A / B / A+B, 200 μM) of peptides treated alone was established to assess baseline safety. The culture medium was changed to contain the corresponding peptide and glutamate, and cells were cultured for another 24 hours. CCK-8 reagent was then added to each well, and after 1 hour of incubation, absorbance (OD value) was measured at 450 nm to calculate cell viability.

[0086] The survival rate of SH-SY5Y cells treated with a single peptide FDDGPFF(A) was as follows: Figure 3 As shown, the survival rate of SH-SY5Y cells treated with a single peptide LFGGF(B) is as follows: Figure 4 As shown, the survival rate of SH-SY5Y cells treated with the composite peptide FDDGPFF (A) + LFGGF (B) is as follows: Figure 5 As shown in the figure, treatment with 8 mM glutamate significantly reduced the viability of SH-SY5Y cells to approximately 50% (P<0.01 compared to the CK group). In the glutamate injury model, peptides FDDGPFF (A), LFGGF (B), and their combination (A+B) all dose-dependently improved cell viability. At a concentration of 200 μM, the combination (A+B) showed the best protective effect, restoring cell viability to over 85%, significantly superior to single peptides at the same concentration (P<0.05). Furthermore, the peptides did not exhibit significant toxicity when used alone to treat normal cells at a concentration of 200 μM, confirming their safety.

[0087] 2. Verification by live / dead cell staining

[0088] Cells were seeded in 24-well plates, with three groups: a normal control (CK), a glutamate-damaged group (Glu, 8 mM), and a protection group supplemented with 200 μM peptides FDDGPFF (A), LFGGF (B), and their combination (A+B, 100 μM each) in addition to glutamate-damaged cells. Four hours after treatment, cells were stained using a Calcein-AM / PI double staining kit. Live cells were labeled with Calcein-AM (emitting green fluorescence), and dead cells were labeled with PI (emitting red fluorescence). Cells were observed and photographed under a fluorescence microscope.

[0089] The results are as follows Figure 6 As shown, cells in the normal control group exhibited dense green fluorescence; the glutamate-damaged group showed a large amount of red fluorescence (dead cells), and green fluorescence was significantly reduced. In each peptide protection group, the number of red fluorescent cells was significantly reduced, and green fluorescence was enhanced. Among them, the cell morphology of the combination (A+B) treatment group was closest to that of the normal group, which directly confirmed its ability to reduce glutamate-induced apoptosis / necrosis and maintain cell viability.

[0090] In summary, the quinoa active peptides FDDGPFF (A), LFGGF (B) and their combinations described in this invention can directly resist glutamate-induced neuronal cytotoxicity, improve cell survival rate, and exhibit clear in vitro neuroprotective activity. Furthermore, their combined use shows a synergistic effect.

[0091] Example 4

[0092] In vitro antioxidant activity assay of quinoa bioactive peptides

[0093] Using PBS (pH=7.2) solvent, single peptide solutions of quinoa active peptides FDDGPFF (A), LFGGF (B), and complex peptide solutions (A+B) were prepared. The concentrations of FDDGPFF and LFGGF in the single peptide solutions were 1 mg / mL, and the concentrations of FDDGPFF and LFGGF in the complex peptide solutions were 0.5 mg / mL and 0.5 mg / mL, respectively.

[0094] The in vitro antioxidant activities of quinoa mixed peptide components (HDP, concentration 1 mg / mL), single peptide solutions of quinoa active peptides FDDGPFF (A), LFGGF (B), and complex peptide solutions (A+B) were determined, including DPPH scavenging rate, ABTS free radical scavenging rate, and FRAP antioxidant activity. Results are as follows: Figure 7As shown, the composite peptide (A+B) solution exhibited the strongest in vitro antioxidant activity (all indicators were significantly higher than other groups); the single peptide solutions FDDGPFF (A) and LFGGF (B) showed similar antioxidant capacities at a moderate level; while the mixed peptide HDP showed the weakest antioxidant capacity. The trends of the three indicators were completely consistent, indicating that there is a significant synergistic antioxidant effect after combining peptide A and peptide B, and its antioxidant activity is significantly better than that of the single peptide and the original mixed peptide.

[0095] Example 4

[0096] The molecular weight distribution of quinoa mixed peptide fractions (HDPs) with molecular weights <3 kDa after ultrafiltration was determined by HPLC. The test conditions were as follows: TSK G2000SWXL gel column (300 nm × 7.8 nm inner diameter); detection wavelength, 280 nm; sample concentration, 5 mg / mL; mobile phase, 30% acetonitrile (containing 0.1% trifluoroacetic acid), 55% ultrapure water; flow rate, 0.5 mL / min; injection volume, 20 μL. Molecular weight standards were cytochrome C (12384 Da), aprotinin (6512 Da), bacitracin (1450 Da), L-glutathione (651 Da), and glycine (75 Da). The molecular weight range of the ultrafiltration hydrolysates was determined.

[0097] The results are as follows Figure 8 and Figure 9 As shown, the components with a molecular weight < 1 kDa accounted for the largest proportion, while the components with a molecular weight of 1-1.5 kDa and 1.5-3 kDa accounted for a smaller proportion, indicating that the components of this sample are mainly low molecular weight (< 1 kDa) substances.

[0098] In vivo efficacy verification of quinoa malt peptide (HDP) in improving cognitive function

[0099] 1. Animal Model Establishment and Grouping: A mouse aging model was induced by subcutaneous injection of D-galactose (150 mg / kg / d) for 8 consecutive weeks. Mice were randomly divided into 4 groups: normal control group, model group, positive control drug piracetam group (400 mg / kg / d), and medium-dose HDP (quinoa active peptide component) group (200 mg / kg / d), with 10 mice in each group. Each group was administered the corresponding test drug by gavage daily for 8 consecutive weeks.

[0100] 2. Behavioral Test (Morris Water Maze):

[0101] The mice in each group underwent a navigational orientation experiment to assess their spatial learning ability and spatial memory retention ability. The specific methods are as follows:

[0102] A circular water tank was used as a water maze. Several visual cues were fixed to the walls surrounding the tank to provide spatial reference and remained constant throughout the experiment. The tank was virtually divided into four quadrants: Northeast (I), Northwest (II), Southwest (III), and Southeast (IV). A circular platform (12 cm in diameter) was fixed in the center of the Northeast (I) quadrant and always submerged approximately 1 cm below the water surface. Each mouse underwent the experiment four times a day for four consecutive days; an infrared camera (Nikon, Melville, NY, USA) was mounted directly above the water maze tank to record each mouse's swimming path length (swimming distance), time taken to reach the underwater platform (escape latency), time to enter the platform, and the percentage of swimming distance traversed in the target quadrant. The latency period was the time it took for the mouse to find and climb onto the hidden platform. After climbing onto the hidden platform, the mouse was required to remain on it for 20 seconds. If the mouse did not reach the hidden platform within 120 seconds, it was guided to the hidden platform and remained there for 20 seconds. On day five, the platform was removed, and the mice were allowed to swim freely for 120 seconds. The number of times each mouse crossed the original platform location within 120 seconds was recorded. Swimming paths were recorded and analyzed in this experiment. Performance on days four and five was used as the final results of the navigation and exploration tests, respectively, to assess spatial memory.

[0103] The movement trajectories of mice in different groups in the Morris water maze experiment are as follows: Figure 10 As shown, learning and memory abilities were assessed by recording the paths mice took to find the platform: Blank group: The trajectory was more concentrated, and the mice could quickly approach the platform, reflecting normal spatial memory ability; Model group: The trajectory was messy and involved large-scale circling, indicating that the spatial memory of the mice was impaired after modeling; Positive group and HDP group: The trajectory was closer to the blank group, and the mice could approach the platform more efficiently, indicating that HDP can improve the spatial memory deficit of the model mice.

[0104] Figure 11 These are quantitative indicators from the Morris water maze experiment, reflecting the spatial memory ability of mice from different dimensions. Figure 11 It can be seen that, in terms of swimming distance, the total swimming length of the model group was significantly longer than that of the control group (normal group), while the distance was shorter in the positive group and HDP group. During the escape latency, the time to find the platform was significantly longer in the model group, while shorter in the positive group and HDP group. Regarding the number of platform crossings, the model group crossed the original platform far less often than the control group, while the number of crossings increased in the positive group and HDP group. In terms of quadrant ratio, the proportion of time spent in the original platform quadrant was significantly reduced in the model group, while the proportion increased in the positive group and HDP group. These results consistently indicate that modeling impairs spatial memory in mice, and HDP can effectively improve the spatial memory ability of model mice by shortening swimming distance and latency, increasing the number of platform crossings, and improving the quadrant ratio.

[0105] In summary, the aging model group exhibited significant spatial memory impairment, confirming the successful establishment of the aging model. The positive control group showed some improvement: the activity distance and number of platform crossings were significantly higher than those in the model group, but the improvement showed significant individual differences. The HDP group showed the best improvement, indicating that quinoa protein peptides are effective in improving memory decline.

[0106] 3. Biochemical indicator testing:

[0107] Eight weeks after drug treatment, the mice were sacrificed, and the antioxidant capacity of each group of mice was tested according to the instructions using a kit produced by Suzhou Greens Co., Ltd. The results are as follows: Figures 12-14 As shown, after HDP intervention, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in mouse serum were significantly increased, while the content of malondialdehyde (MDA) was significantly decreased.

[0108] Eight weeks after drug treatment, the mice were sacrificed, and brain-derived neurotrophic factor in the brains of each group of mice was detected using an ELISA kit from Jiangsu Jingmei Co., Ltd., according to the instructions. The results are as follows: Figure 15 As shown, BDNF (brain-derived neurotrophic factor) is a key factor in promoting neuronal survival and synaptic plasticity, and is directly related to learning and memory functions. The concentration of BDNF in the brain is shown in the figure in "ng / mgprot". HDP can increase the level of brain-derived neurotrophic factor (BDNF) in the brain of aging mice.

[0109] 4. Histopathological observation: After 8 weeks of drug treatment, mice were sacrificed, and hippocampal tissue from each group was collected for HE staining. The results are as follows: Figure 16 As shown, the hippocampus and its subregions in the model group showed obvious tissue damage (such as disordered cell arrangement, increased gaps, and loose structure); while the tissue morphology of the HDP group was closer to that of the blank group and the positive group, indicating that high-dose quinoa malt peptides can improve the hippocampal tissue structure damage in model mice.

[0110] 5. Body weight changes were tracked during the 10-week drug administration period in the negative control group (normal mice), model group (mice with induced malnutrition), positive control group (treated with positive drug), and quinoa peptide treatment group (HDP). Results are as follows: Figure 17 As shown, the weight of each group was similar at the beginning of the experiment (about 20g). As the administration time increased, the weight of each group showed an upward trend. The weight gain of the model group was relatively slow, while the weight gain trend of the quinoa peptide treatment group was closer to that of the negative and positive groups. This indicates that quinoa peptide did not have an adverse effect on the weight of the mice, and may have improved the nutritional status or health of the model mice.

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. Quinoa active peptide with antioxidant and neuroprotective effects, characterized by, The amino acid sequence of the quinoa active peptide is at least one of FDDGPFF and LFGGF.

2. The use of the active peptide from quinoa in the preparation of a product with antioxidant and neuroprotective effects according to claim 1, characterized in that, The product is a medicine. 3.The use of the active peptide of quinoa in the preparation of a product with antioxidant and neuroprotective effects according to claim 2, characterized in that, The medicine further comprises a pharmaceutically acceptable excipient. 4.The use of the active peptide of quinoa in the preparation of a product with antioxidant and neuroprotective effects according to claim 2, characterized in that, The antioxidation is DPPH free radical, ABTS free radical scavenging effect and FRAP antioxidant activity. 5.The use of the active peptide of quinoa in the preparation of a product with antioxidant and neuroprotective effects according to claim 2, characterized in that, The neuroprotective effect is to reduce glutamate-induced neuron cell damage and improve cell survival rate. 6.The use of the active peptide of quinoa in the preparation of a product with antioxidant and neuroprotective effects according to claim 2, characterized in that, The neuroprotective effect is to improve cognitive dysfunction, including improving spatial learning ability and enhancing memory retention ability.

7. The use of the active peptide of quinoa with antioxidant and neuroprotective effects according to claim 2 for the preparation of products with antioxidant and neuroprotective effects, characterized by, The neuroprotective effect is achieved by increasing the level of brain-derived neurotrophic factor in the brain and enhancing the antioxidant capacity of brain tissue.

8. A preparation having antioxidant and neuroprotective effects, characterized by, The effective component is at least one of FDDGPFF and LFGGF. 9.The preparation with antioxidant and neuroprotective effects according to claim 8, characterized in that, The concentration of the effective component is 0.5-1 mg / mL.

Images