Plant-extracted polypeptide and its use in treating hypertension

Abstract

This invention relates to a polypeptide extracted from a plant and its application in the treatment of hypertension. Specifically, it provides a highly active antihypertensive polypeptide isolated and prepared from bitter melon peel, which exhibits good ACE inhibitory activity. Experiments in a rat hypertension model have demonstrated that this polypeptide has a good blood pressure-lowering effect and good safety profile, showing significant application potential.

Description

Technical Field

[0001] This application relates to the field of biology, specifically to a plant-extracted polypeptide and its application in the treatment of hypertension. Background Technology

[0002] With the accelerating pace of our lives, unhealthy diets and lifestyles have led to a growing incidence of hypertension. Maintaining normal blood pressure is crucial for the proper functioning of all organs and tissues. Arterial blood pressure varies with age and physiological state. Currently, the World Health Organization recommends the following blood pressure diagnostic criteria: ≤140 mmHg / 90 mmHg for resting blood pressure in normal individuals; adults whose blood pressure consistently exceeds these standards can be diagnosed with hypertension. Hypertension can be classified into primary and secondary types. Clinically, based on the speed of onset and progression, hypertension is further divided into slow-onset and rapid-onset types. The significant pathophysiological changes in hypertension include increased peripheral vascular resistance, narrowing of arterioles, and elevated blood pressure. These changes are closely related to sympathetic nervous system dysfunction, and in some patients, they are associated with increased plasma renin activity. In the early stages of the disease, increased smooth muscle tone in systemic small arteries leads to elevated blood pressure. After years of sustained high blood pressure, systemic arteriosclerosis, luminal narrowing, and decreased vessel wall elasticity can occur, further exacerbating hypertension. Common complications of hypertension include coronary heart disease, diabetes, heart failure, hyperlipidemia, kidney disease, peripheral artery disease, and stroke.

[0003] Currently, the main categories of antihypertensive drugs used are diuretics, beta-blockers, alpha-blockers, calcium channel blockers, angiotensin-converting enzyme inhibitors, and angiotensin II receptor antagonists. Existing antihypertensive drugs affect blood pressure regulation directly or indirectly. Based on their primary sites of action and mechanisms of action in blood pressure regulation, they can be broadly categorized as: drugs acting on the central nervous system, such as clonidine and moxonidine; and ganglion blocking drugs, such as mecamidine and mithifene. This class of drugs blocks both sympathetic and parasympathetic ganglia, which can cause widespread and severe adverse reactions. Therefore, they are usually only used for rapid blood pressure reduction in severe hypertension or "hypertensive crisis" when other drugs are ineffective. Other drugs include those that affect adrenergic neurotransmitters, such as reserpine and guanethidine; adrenergic receptor blockers, such as prazosin and propranolol; vasodilators, such as hydralazine; calcium channel blockers, such as nifedipine and amlodipine; the basic function of calcium channel blockers is to inhibit the influx of extracellular calcium ions, which, in terms of blood vessels, relaxes smooth muscle cells, dilates blood vessels, and lowers blood pressure; diuretics, such as hydrochlorothiazide; and drugs that affect the renin-angiotensin system, such as captopril.

[0004] However, with the changes in the condition and the resulting side effects, controlling and curing hypertension has become a challenge, leading to a new stage in the research of antihypertensive drugs.

[0005] Blood pressure-lowering peptides are a type of bioactive peptide, also known as angiotensin-converting enzyme (ACE) inhibitory peptides. Compared to chemical antihypertensive drugs, food-derived blood pressure-lowering peptides have advantages such as high safety, strong digestibility and absorption, mild blood pressure-lowering effect without affecting normal blood pressure, and no side effects. Blood pressure-lowering peptides have become one of the most popular research directions in the field of bioactive peptides. Currently, the most widely studied method is to obtain blood pressure-lowering peptides from bovine milk protein. A 12-peptide with ACE inhibitory activity, with the structure FFVAPFPEVFGK, was obtained from the trypsin hydrolysate of bovine milk casein. α-casein and β-casein were hydrolyzed using Lactobacillus helveticus CP790 protease, and the hydrolysate was separated by reversed-phase high-performance liquid chromatography. Its activity was verified through experiments on essential hypertensive rats, and a peptide chain with the amino acid sequence Lys-Val-Leu-Pro-Val-Pro-Gln was found to have strong ACE inhibitory activity. A 23-peptide with ACE inhibitory activity was synthesized using a segmented solid-phase method targeting human κ-casein. Besides casein, some researchers have also obtained blood pressure-lowering peptides from whey protein. Li Chaohui et al. hydrolyzed whey protein using neutral protease, alkaline protease, pepsin, trypsin, and papain to obtain antihypertensive peptides, and confirmed that the alkaline protease hydrolysate had the highest activity. Oligopeptides with antihypertensive effects have been obtained from proteins of various fish and shellfish, including sardines, tuna, Antarctic krill, cod, and bonito. Senmi Co., Ltd. in Japan has produced sardine peptides, whose main component is ACE inhibitory peptide, with 2-10 amino acid residues, no bitter taste, and can be directly added to various foods for the prevention and treatment of hypertension. Studies have also shown that antihypertensive peptides extracted from silver carp and mussels, when fed to mice with hypertension at a dose of 3g per kilogram of mice, reduced blood pressure by 20-25 mmHg within 6 hours, with a maximum reduction of 30 mmHg, demonstrating a highly significant effect. Safety tests have proven that these peptides are safe and have no toxic side effects.

[0006] Currently, although there has been much research on using bioactive peptides to prepare antihypertensive peptides, the variety of highly active antihypertensive peptides is still insufficient and needs further improvement. Summary of the Invention

[0007] The inventors discovered in their research that existing technologies already exist that can isolate and obtain blood pressure-lowering active polypeptides from bitter melon peel, but the activity is not very high. Building upon this, the inventors, through long-term research, discovered that highly active blood pressure-lowering polypeptides can be isolated and obtained from bitter melon peel.

[0008] This invention provides a specific antihypertensive polypeptide, named Sh-CF-5, whose amino acid sequence is shown in SEQ ID NO: 1.

[0009] In some embodiments, the polypeptide exhibits at least about 30-40% sequence homology or identity with a reference polypeptide, and typically greater than about 50%, 60%, 70%, 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher, and / or includes at least one region (e.g., a conserved region, which in some embodiments may be or include a characteristic sequence element) exhibiting very high sequence identity, typically greater than 90% or even 95%, 96%, 97%, 98% or 99%. Such conserved regions typically contain at least 3-4, and in some cases up to 20 or more amino acids; in some embodiments, the conserved region covers at least one segment of at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or more consecutive amino acids.

[0010] The present invention further provides a pharmaceutical composition for treating hypertension, comprising the antihypertensive polypeptide Sh-CF-5, the amino acid sequence of which is shown in SEQ ID NO: 1.

[0011] In some embodiments, the pharmaceutical compositions provided herein comprise about 1 pg to about 2,000 mg of a polypeptide (e.g., a polypeptide component, which may be a single polypeptide in some embodiments), optionally wherein the pharmaceutical composition comprises about 1 pg to about 1,000 mg, about 1 pg to about 500 mg, about 1 pg to about 400 mg, about 1 pg to about 300 mg, about 1 pg to about 200 mg, about 1 pg to about 100 mg, about 1 pg to about 50 mg, about 1 pg to about 25 mg, about 1 pg to about 20 mg, about 1 pg to about 15 mg, about 1 pg to about 10 mg, about 1 pg to About 5 mg, about 1 pg to about 1 mg, about 1 pg to about 500 pg, about 1 pg to about 250 pg, about 1 pg to about 200 pg, about 1 pg to about 150 pg, about 1 pg to about 100 pg, about 1 pg to about 50 pg, about 1 mg to about 1000 mg, about 1 mg to about 500 mg, about 1 mg to about 400 mg, about 1 mg to about 300 mg, about 1 mg to about 200 mg, about 1 mg to about 100 mg, about 1 mg to about 50 mg, about 1 mg to about 25 mg of polypeptides (e.g., polypeptide components, which in some embodiments may be a single polypeptide).

[0012] Therapeutic Effective Amount: As used herein, “therapeutic effective amount” refers to the amount that produces the desired effect of its administration. In some embodiments, the term refers to an amount sufficient to treat a disease, condition, and / or illness when administered according to a therapeutic dosing regimen to a population suffering from or susceptible to such a disease, condition, and / or illness. In some embodiments, a therapeutic effective amount is an amount that reduces the incidence and / or severity of one or more symptoms of a disease, condition, and / or illness, and / or delays its onset. Those skilled in the art will understand that a therapeutic effective amount does not necessarily achieve successful treatment in every particular individual. Rather, a therapeutic effective amount can be an amount that provides a specific desired pharmacological response in a large number of subjects when administered to patients who require such treatment. In some embodiments, references to a therapeutic effective amount can be to an amount measured in one or more specific tissues (e.g., tissues affected by a disease, condition, or illness) or fluids (e.g., blood, saliva, serum, sweat, tears, urine, etc.). Those skilled in the art will understand that in some embodiments, a specific agent or therapy can be formulated and / or administered in a single dose. In some implementations, the therapeutic agent may be formulated and / or administered in multiple doses, for example, as part of a dosing regimen.

[0013] The pharmaceutical composition of the present invention further contains a pharmaceutically acceptable carrier.

[0014] Furthermore, the pharmaceutical compositions of the present invention can be oral dosage forms. Solid dosage forms for oral administration include capsules, tablets, pills, powders, and granules. In these solid dosage forms, the active polypeptide is mixed with at least one conventional inert excipient (or carrier), such as sodium citrate or dicalcium phosphate, or with the following components: (a) fillers or solubilizers, such as starch, lactose, sucrose, glucose, mannitol, and silica; (b) binders, such as hydroxymethyl cellulose, alginate, gelatin, polyvinylpyrrolidone, sucrose, and gum arabic; (c) humectants, such as glycerin; (d) disintegrants, such as agar, calcium carbonate, potato starch or cassava starch, alginate, certain complex silicates, and sodium carbonate; (e) slowing agents, such as paraffin wax; (f) absorption accelerators, such as quaternary ammonium compounds; (g) wetting agents, such as cetyl alcohol and glyceryl monostearate; (h) adsorbents, such as kaolin; (i) lubricants, such as talc, calcium stearate, magnesium stearate, solid polyethylene glycol, sodium dodecyl sulfate, or mixtures thereof. In capsules, tablets, and pills, the dosage form may also contain a buffer. Solid dosage forms, such as tablets, sugar pills, capsules, pellets, and granules, can be prepared using coatings and shells, such as casings and other materials known in the art. They may contain opaque agents, and the release of the active peptide or peptide in such compositions may be delayed at a site in the digestive tract. Examples of encapsulating components that may be used are polymeric substances and waxes. If necessary, the active peptide may also be formed into microcapsules with one or more of the excipients described above. Liquid dosage forms for oral administration include pharmaceutically acceptable emulsions, solutions, suspensions, syrups, or tinctures. In addition to the active peptide, liquid dosage forms may contain inert diluents conventionally used in the art, such as water or other solvents, solubilizers and emulsifiers, such as ethanol, isopropanol, ethyl carbonate, ethyl acetate, propylene glycol, 1,3-butanediol, dimethylformamide, and oils, particularly cottonseed oil, peanut oil, corn germ oil, olive oil, castor oil, and sesame oil, or mixtures of these substances.

[0015] The provided formulation may include lyophilization protectants, such as those selected from sucrose, lactose, trehalose, dextran, erythritol, arabinitol, xylitol, sorbitol, maltose, lactulose, maltulose, glucol, maltitol, lactitol, isomaltulose, and mannitol; amino acids, such as arginine, histidine, proline, or glycine; lyotropic salts, such as magnesium sulfate; propylene glycol, glycerol, poly(ethylene glycol), or poly(propylene glycol); gelatin, dextrin, modified starch, carboxymethyl cellulose, and combinations thereof.

[0016] Alternatively or additionally, in some embodiments, the provided formulation may comprise a penetration enhancer, such as one selected from bile salts, such as sodium trihydroxycholate, sodium glycocholate, sodium taurocholate and dihydroxycholate, sodium deoxycholate, sodium glycodeoxycholate, sodium taurodeoxycholate; fatty acids, their salts and esters, such as oleic acid, lauric acid, cod liver oil extract, sodium lauryl laurate, sodium decanoate, glyceryl monostearate, diethylene glycol monoethyl ether and various sucrose fatty acid esters, medium-chain fatty acid glycerides, polycaprolactone eoma-3 fatty acids, lecithin (phosphatidylcholine), lysophosphatidylcholine; surfactants, such as sodium lauryl sulfate, polysorbate (polysorbate 80), lauryl ether, Brijs and benzalkonium chloride; complexing agents, such as cyclodextrin, dextran sulfate, ethylenediaminetetraacetic acid sodium salt; complexing agents, such as cyclodextrin, dextran sulfate, ethylenediaminetetraacetic acid sodium salt; Dextran, sodium EDTA, cosolvents such as ethanol and propylene glycol, a combination of 1% oleic acid and 5% / 10% polyethylene glycol 200, a combination of 2% glyceryl monolaurate and 40% alcohol, sodium decanoate and alcohol or propylene glycol, a combination of 10% lauric acid in propylene glycol, polyoxyethylene, 2,3-lauryl ether, menthol, sodium decanoate, sodium octanoate, sodium glycinate, ethylene glycol; polysaccharides such as chitosan and chitosan glutamate; and others It includes, for example, aprotinin, benzalkonium chloride, hexadecylpyridinium chloride, hexadecyltrimethylammonium bromide, sodium salicylate, lysophosphatidylcholine, methoxysalicylate, hydroxymethyl oleate, sodium EDTA, sulfoxide, various alkyl glycosides, ethylenediaminetetraacetic acid (EDTA), tartaric acid; lyotropic salts, such as magnesium sulfate; propylene glycol, glycerol, poly(ethylene glycol) or poly(propylene glycol); gelatin, dextrin, modified starch, carboxymethyl cellulose and combinations thereof.

[0017] Optionally or additionally, in some embodiments, the provided formulation may include an absorption enhancer, such as one selected from surfactants, cholesterol, glycerides, salicylates, bile salts, chelating agents, sodium decanoate, salts of decanoate, and others including N-(5-chlorosalicylic acid)-8-aminooctanoic acid (5-CNAC), 4-((4-chloro-2-hydroxybenzoyl))-amino)butyric acid (4-CNAB), and N-(8-(2-hydroxybenzoyl))-amino)octanoic acid, also known as sodium salicylate (SNAC, octanoic acid, C8, castor oil, medium chain, acylcarnitine, EDTA, glyceryl monolaurate, bovine P-casein, tocopheryl succinate glycol chitosan conjugate, lecithin, glyceryl monostearate (GMS), chitosan and alginate, PLGA, silica, stearic acid, oleic acid, hydrogenated castor oil and trimyristic acid glyceride, etoposide phosphate. Sulinic acid Enalapril maleate Remiple Olmesartan medoxomil Valacyclovir Mido-kun Gabapendin Inakabi sulfasalazine Alternatively or additionally, in some embodiments, the provided formulation may comprise a mucosal bioadhesive, such as that selected from sucrose, lactose, trehalose, dextran, erythritol, arabinitol, xylitol, sorbitol, maltose, lactulose, maltulose, glucosyl alcohol, maltitol, lactitol, isomaltulose, and mannitol; amino acids, such as arginine, histidine, proline, or glycine; lyotropic salts, such as magnesium sulfate; propylene glycol, glycerol, poly(ethylene glycol), or poly(propylene glycol); gelatin, dextrin, modified starch, carboxymethyl cellulose, and combinations thereof; and a mucosal adhesion system, such as one derived from natural sources. Mucosal adhesion systems, such as gelatin, agarose, chitosan, hyaluronic acid, and synthetic polymers, such as polyvinylpyrrolidone (PVP), polyacrylate, polyvinyl alcohol, sodium carboxymethyl cellulose (SCMC), and pectin; all anionic polymers, chitosan (cationic) and hydroxypropyl methylcellulose (HPMC) as a nonionic polymer; polyacrylic acid (PAA) derivatives (CP934, CP940, PCP); 15% CMC and 35% CP; copolymers of acrylic acid and poly(ethylene glycol) monomethyl ether monomethacrylate (PEGMM); eudragitl NE40D is a neutral poly(ethyl acrylate methacrylate); hydrophilic polymers, for example. Methocel K4M, Methocel K15M, SCMC 400, Cekol 700, Cekol 10000, CP934P, CP971P and CP974P, Carboxyvinyl Polymers and Triethanolamine, HPC (Hydroxypropyl Cellulose), CP (Carbopoise 934P), Carbopoise (CP) Ex-55CMC (Sodium Carboxymethyl Cellulose), HPMC (Hydroxypropyl Methyl Cellulose), HEC (Hydroxyethyl Cellulose), PIP (Poly(Isoprene)), PIB (Poly(Isobutylene)), Xanthan Gum, Locust Bean Gum, Pectin, Polycarbofil, Benzyl Ester, Hydroxyethyl Cellulose, Poly(Acrylic Acid), Poly(Acrylic Acid-Co-Acrylamide), Poly(Acrylic Acid-Co-Methyl Methacrylate), Poly(Acrylic Acid-Co-Butyl Acrylate), (A bioadhesive polymer blend of CP and PIB), a formulation consisting of PVP, hexadecylpyridinium chloride (as a stabilizer), chlorinated chitosan, polyethylene oxide, polymethyl vinyl ether / maleic anhydride (PME / MA) and tragacanth gum, polyethylene glycol monomethyl ether monomethyl acrylate, drum-dried waxy corn starch (DDWM), carbopol 974P and stearyl fumarate sodium, and cellulose derivatives; hydrogels of acrylic acid (polar) and butyl acrylate (nonpolar) and combinations thereof.

[0018] In addition to these inert diluents, the composition may also contain auxiliaries such as wetting agents, emulsifiers and suspending agents, sweeteners, flavoring agents and fragrances.

[0019] In addition to active peptides, suspensions may contain suspending agents such as ethoxylated isooctadecyl alcohol, polyoxyethylene sorbitol and dehydrated sorbitol esters, microcrystalline cellulose, aluminum methoxide and agar, or mixtures of these substances.

[0020] Compositions for parenteral injection may comprise physiologically acceptable sterile aqueous or anhydrous solutions, dispersions, suspensions, or emulsions, and sterile powders for reconstitution into sterile injectable solutions or dispersions. Suitable aqueous and non-aqueous carriers, diluents, solvents, or excipients include water, ethanol, polyols, and suitable mixtures thereof.

[0021] Dosage forms of the polypeptides of the present invention for topical administration include ointments, powders, patches, sprays, and inhalers. The active ingredient is mixed under sterile conditions with a physiologically acceptable carrier and any preservatives, buffers, or, if necessary, propellants.

[0022] Beneficial effects

[0023] This invention relates to a polypeptide extracted from a plant and its application in the treatment of hypertension. Specifically, it provides a highly active antihypertensive polypeptide isolated and prepared from bitter melon peel, which exhibits good ACE inhibitory activity. Experiments in a rat hypertension model have demonstrated that this polypeptide has a good blood pressure-lowering effect and good safety profile, showing significant application potential. Attached Figure Description

[0024] Figure 1 Inhibition effect of each group on ACE Detailed Implementation

[0025] Specific embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0026] Example 1: Isolation and preparation of highly active antihypertensive polypeptides from bitter melon peel

[0027] Take fresh bitter melon, wash it with clean water to remove impurities, then take 50g of bitter melon peel and crush it into a paste. Under the conditions of a material-to-liquid ratio of 1:3 (g:mL), 3% papain, pH 7.0, and enzymatic hydrolysis temperature of 58℃, hydrolyze for 4 hours. Inactivate the enzyme in boiling water at 95℃ for 10 minutes, cool to room temperature and adjust the pH to 7.0. Centrifuge at 9000r / min for 20 minutes, collect the supernatant and freeze-dry it to obtain the bitter melon peel enzymatic hydrolysate.

[0028] The ACE inhibition rate (IC50) of the bitter gourd peel enzymatic hydrolysate was determined using ultrafiltration membranes with relative molecular mass cutoffs of 30,000, 10,000, and 6,000 for fractions above 30,000, 30,000-10,000, 10,000-6,000, and 6,000. 50 The fraction with the highest activity was collected and lyophilized for preservation. The ACE inhibition rate was determined as follows: 5 μL of enzymatic hydrolysate (5 mg / mL) and 15 μL of ACE (60 mU / mL) were added to 0.5 mL Eppendof tubes, incubated at 37°C for 5 min, followed by the addition of 25 μL of HHL (7.6 mmol / L) and reaction at 37°C for 25 min. The reaction was terminated by adding 5 μL of 0.1% TFA solution. After cooling to room temperature and filtering through a 0.22 mm cellulose acetate membrane, the amount of hippuric acid produced by the reaction of ACE with the substrate was quantified using RP-HPLC to determine the ACE inhibitory activity. The ACE inhibition rate was calculated as: ACE inhibition rate = (control hippuric acid peak area - sample hippuric acid peak area) / control hippuric acid peak area x 100%. The IC50 was obtained based on the inhibition rate. 50 The values ​​are shown in Table 1.

[0029] Table 1. Inhibition IC50 of each component on ACE 50 value

[0030] Components volume / mL <![CDATA[IC 50 / (mg / mL)]]> Bitter melon peel enzymatic hydrolysate 175 55.37 More than 30,000 34 75.68 30000-10000 39 59.87 10000-6000 20 32.18 6000 down 82 10.13

[0031] As shown in Table 1, the activity of the fractions with molecular weight cutoff increases with decreasing molecular weight. The highest activity is observed at molecular weight 6000, with an IC50 value of [missing value]. 50 The concentration reached 10.13 mg / mL. Therefore, the fraction collected at 6000 °C was lyophilized and stored for further separation.

[0032] The aforementioned components with activity below 6000 were loaded onto a Sephadex G-25 column at a concentration of 1 g / 10 mL distilled water for elution at a flow rate of 2 mL / 10 min. An automated sample collection system was used for analysis. The density of each collected sample was measured at 280 nm, yielding four high-protein concentration peaks, named A, B, C, and D. These peaks were then analyzed using the aforementioned ACE inhibition rate assay, revealing that peak C exhibited the highest inhibitory activity. Peak C was subsequently purified by reversed-phase high-performance liquid chromatography (RP-HPLC). The initial RP-HPLC separation used a sample concentration of 4 mg / mL, a loading volume of 20 μL, and a Hypersil BDS C10 column. 18 The column was 250 mm x 4.6 mm, 5 μm in size. The mobile phase was 20% acetonitrile containing 0.1% TFA, the flow rate was 1 mL / min, the column temperature was 25 °C, and the detection wavelength was 215 nm. The separated components were collected multiple times, lyophilized, and then subjected to ACE inhibitory activity assays. The most active component, number 2, was separated a second time. In the second RP-HPLC separation, the conditions were identical to the first, except that the mobile phase was 10% acetonitrile containing 0.1% TFA. The separated components were then subjected to ACE inhibitory activity assays. The most active component was analyzed by mass spectrometry, and sequence analysis revealed a highly active antihypertensive peptide, Sh-CF-5, whose amino acid sequence is shown in SEQ ID NO: 1.

[0033] Example 2: Biological activity of the antihypertensive peptide Sh-CF-5

[0034] The antihypertensive peptide Sh-CF-5 was prepared at three concentrations (100 μg / mL, 200 μg / mL, and 500 μg / mL) for ACE inhibition rate determination. Captopril at 100 μg / mL served as a positive control. Distilled water was used as the blank control group. The ACE inhibition rate was determined as follows: 5 μL of the peptide and 15 μL of ACE (60 mU / mL) were added to 0.5 mL Eppendof tubes, incubated at 37°C for 5 min, followed by the addition of 25 μL of HHL (7.6 mmol / L) and reaction at 37°C for 25 min. The reaction was terminated by adding 5 μL of 0.1% TFA solution. After cooling to room temperature and filtering through a 0.22 mm cellulose acetate membrane, the amount of hippuric acid produced by the reaction of ACE with the substrate was quantified using RP-HPLC to determine the ACE inhibitory activity. The formula for calculating the ACE inhibition rate is: ACE inhibition rate = (peak area of ​​control hippuric acid - peak area of ​​sample hippuric acid) / peak area of ​​control hippuric acid x 100%. The results are as follows: Figure 1 As shown.

[0035] from Figure 1It can be seen that the antihypertensive peptide Sh-CF-5 has a dose-dependent inhibitory effect on ACE. Compared with the positive control group, the low concentration peptide group has a similar inhibitory effect, and the inhibition rate reaches (97.12±1.27)% under high concentration conditions.

[0036] Example 3: Animal experiments with the antihypertensive peptide Sh-CF-5

[0037] Male essential hypertensive rats (SHR) used in the experiment were purchased from Changzhou Cavens Laboratory Animal Co., Ltd. They were SPF grade, weighing 220-270g, 12 weeks old, with systolic blood pressure exceeding 180mHg. After 3 days of acclimatization, the SHR were randomly divided into a blank control group, a positive control group (captopril), a low-dose peptide group, and a high-dose peptide group, administered via gavage. The specific administration conditions were as follows: For the blank control group, distilled water was administered at a gavage dose of 100 mg / kg; for the positive control group, captopril was administered at a gavage dose of 40 mg / kg; for the low-dose peptide group, the gavage dose was 40 mg / kg; and for the high-dose peptide group, the gavage dose was 100 mg / kg. Animal housing conditions: SHRs were housed in an SPF-grade 12 / 12h dark / light chamber at a temperature of (22±2)℃, with free access to food and water. Bedding was changed every 5 days. Administration was performed twice daily, once between 8:00-9:00 AM and again between 8:00-9:00 PM, for a total of 30 days. The systolic blood pressure of SHRs was measured using the tail-neck method on day 0 and day 30 after administration. Three measurements were taken for each SHR, and the average value was recorded. The results are shown in Table 2.

[0038] Table 2. Systolic blood pressure (SBP / mmHg) for each group

[0039] Group Systolic blood pressure (SBP / mmHg) Blank control group 198.6±5.1 Positive control group 146.4±3.7# Low-dose peptide group 148.5±2.9# High-dose peptide group 142.3±3.4#

[0040] As shown in Table 2, the positive control group, the low-dose peptide group, and the high-dose peptide group were significantly different from the blank control group (P<0.05). The low-dose peptide group had a similar antihypertensive effect to the positive control group.

[0041] Furthermore, the effects of the drug on the health of the rats were assessed by measuring their body weight. After administration, body weight was measured in each group. The results showed that the blank control group increased by (19±4) g, the positive control group by (16±2) g, the low-dose peptide group by (20±5) g, and the high-dose peptide group by (18±3) g. The changes in body weight among the groups were not significantly different, indicating that the administered peptide did not impair the normal growth of SHRs. In addition, after dissection, the physiological state of the heart, liver, and kidneys of the rats in each group was found to be intact and consistent, indicating good safety.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An antihypertensive polypeptide Sh-CF-5, characterized in that... The amino acid sequence of the polypeptide is shown in SEQ ID NO:

1.

2. A pharmaceutical composition for treating hypertension, characterized by The active component of the composition is the antihypertensive polypeptide Sh-CF-5, and the amino acid sequence of the polypeptide is shown in SEQ ID NO:

1.

3. Use of the antihypertensive peptide Sh-CF-5 in the preparation of a medicament for the treatment of hypertension, wherein the amino acid sequence of the peptide is shown in SEQ ID NO:

1.

4. Use according to claim 3, characterized in that The drug also contains a pharmaceutically acceptable carrier.

5. Use according to claim 4, characterized in that The carrier includes excipients.

6. Use according to claim 4, characterized in that The carrier includes fillers or solubilizers.

7. Use according to claim 4, characterized in that The carrier includes a slow solvent.

8. The use as described in claim 4, characterized in that The carrier includes a humectant.

9. The use as described in claim 4, characterized in that... The carrier includes a disintegrant.

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