Polypeptide extracted from plants and application of polypeptide in treatment of hypertension

Abstract

The invention relates to a polypeptide extracted from a plant and application of the polypeptide in treatment of hypertension, in particular to a high-activity antihypertensive polypeptide separated and prepared from bitter gourd peel, and the polypeptide has good ACE inhibitory activity. A rat hypertension model experiment proves that the polypeptide has a relatively good blood pressure reducing effect and safety, and has a remarkable application prospect.

Description

Technical Field

[0001] The present application relates to the biological field, and specifically to a plant-extracted polypeptide and its application in treating hypertension. Background Art

[0002] As our pace of life accelerates, poor diet and living habits lead to an increasing incidence of hypertension. Maintaining normal blood pressure is of great significance to the normal functioning of various tissues and organs of the body. Arterial blood pressure varies with age and physiological state. At present, the blood pressure judgment standard recommended by the World Health Organization is: normal blood pressure ≤140mmHg / 90mmHg at rest. Adults whose blood pressure is often higher than the above standard can be diagnosed with hypertension. Hypertension can be divided into primary and secondary types. Clinically, according to the onset of hypertension and the speed of disease progression, it is divided into slow-progressive and rapid-progressive types. The significant pathophysiological changes of hypertension are increased peripheral vascular resistance, smaller arteriolar lumen, and increased blood pressure. These changes are closely related to the dysfunction of the sympathetic nervous system, and some patients are related to increased plasma renin activity. In the early stage of the disease, the tension of the smooth muscles of the small arteries throughout the body increases, causing increased blood pressure. After years of continuous increase in blood pressure, it can cause sclerosis of small arteries throughout the body, narrowing of the lumen, and reduced elasticity of the wall, further exacerbating blood pressure. Common complications of hypertension include coronary heart disease, diabetes, heart failure, hyperlipidemia, kidney disease, peripheral arterial disease, and stroke.

[0003] At present, people mainly use six categories of antihypertensive drugs, including diuretics, beta-blockers, alpha-blockers, calcium ion antagonists, angiotensin converting enzyme inhibitors, and angiotensin II receptor antagonists. Existing antihypertensive drugs affect blood pressure regulation directly or indirectly. According to the main sites and mechanisms of action of various drugs in blood pressure regulation, they are roughly divided into: drugs acting on the central nervous system, such as clonidine, moxonidine, etc.; ganglion blocking drugs, such as mecamylamine, imipenem, etc. This type of drug blocks both the sympathetic ganglia and the parasympathetic ganglia, which can cause widespread and serious adverse reactions. Therefore, it is usually only used to quickly lower blood pressure in severe hypertension or "hypertensive crisis" that is ineffective with other drugs; drugs that affect adrenergic neurotransmitters, such as reserpine, guanethidine, etc.; adrenergic receptor blockers, such as prazosin, propranolol, etc.; vasodilators, such as hydralazine; calcium antagonists, such as nifedipine, amlodipine, etc.; the basic function of calcium antagonists is to inhibit the influx of extracellular calcium ions, which means relaxing smooth muscle cells, dilating blood vessels and lowering blood pressure; diuretics, such as hydrochlorothiazide; drugs that affect the renin-angiotensin system, such as captopril.

[0004] However, with the changes in the disease and the side effects it brings, the control and cure of hypertension has become difficult, so people's research on antihypertensive drugs has entered a new stage.

[0005] Antihypertensive peptides are one type of active peptides, also known as angiotensin converting enzyme inhibitory peptides. Compared with chemical antihypertensive drugs, food-derived antihypertensive peptides have the advantages of high safety, strong digestibility, mild antihypertensive effect, no effect on normal blood pressure, and no side effects. Antihypertensive peptides have become one of the hottest directions in the field of bioactive peptide research. At present, the most widely studied is to obtain antihypertensive peptides from bovine milk protein. 12 peptides with ACE inhibitory activity were obtained from the trypsin hydrolysate of bovine casein, with the structure of FFVAPFPEVFGK. α-casein and β-casein were hydrolyzed with Lactobacillus helveticus CP790 protease, and the hydrolysate was separated by reverse HPLC. Its activity was verified by experiments on primary hypertensive rats, and it was found that the peptide chain with the amino acid sequence Lys-Val-Leu-Pro-Val-Pro-Gln had strong ACE inhibitory activity. 23 peptides with ACE inhibitory activity were synthesized by segmented solid phase method with human κ-casein as the target. In addition to casein as the raw material, some scholars also obtained antihypertensive peptides from whey protein. Li Chaohui and others used neutral protease, alkaline protease, pepsin, trypsin, and papain to hydrolyze whey protein to obtain blood pressure-lowering peptides, and confirmed that the alkaline protease hydrolysate had the greatest activity. People have obtained oligopeptides with blood pressure-lowering effects from a variety of fish and shellfish proteins, such as sardines, tuna, Antarctic krill, cod, and bonito. Japan's Senmi Company has produced sardine peptides whose main component is ACE inhibitory peptides. The number of amino acid residues is 2 to 10, and it does not contain bitterness. It can be directly added to various foods for the prevention and treatment of hypertension. There are also studies showing that blood pressure-lowering peptides extracted from silver carp and mussels are fed to mice with hypertension. Within 6 hours, the blood pressure of these mice was reduced by 20 to 25 mmHg, and the maximum reduction reached 30 mmHg, which is a very significant effect. Safety tests have proven that it is safe and has no toxic side effects.

[0006] At present, although there have been many studies on the preparation of antihypertensive peptides using active peptides, the types of highly active antihypertensive peptides are still insufficient and need to be further improved. Summary of the invention

[0007] The inventors found that in the prior art, active polypeptides that can lower blood pressure can be isolated from bitter melon peel, but the activity is not very high. Based on this, the inventors found that highly active polypeptide substances that can lower blood pressure can be isolated from bitter melon peel based on long-term research.

[0008] The present invention provides a specific antihypertensive polypeptide, the antihypertensive polypeptide is named Sh-CF-5, and its amino acid sequence is shown in SEQ ID NO:1.

[0009] In some embodiments, the polypeptide shows a degree of sequence homology or identity to a reference polypeptide of at least about 30-40%, 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) that shows very high sequence identity, typically greater than 90% or even 95%, 96%, 97%, 98% or 99%. Such a conserved region typically comprises at least 3-4, in some cases up to 20 or more amino acids; in some embodiments, a conserved region encompasses 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 an antihypertensive pharmaceutical composition, which comprises the antihypertensive polypeptide Sh-CF-5, whose amino acid sequence is shown in SEQ ID NO:1.

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

[0012] Therapeutically effective amount: As used herein, "therapeutically effective amount" refers to an amount that produces the desired effect of its administration. In some embodiments, the term refers to an amount sufficient to treat the disease, disorder and / or condition when applied to a population suffering from or susceptible to a disease, disorder and / or condition according to a therapeutic dosing regimen. In some embodiments, a therapeutically effective amount is an amount that reduces the incidence and / or severity of one or more symptoms of a disease, disorder and / or condition, and / or delays its onset. It will be understood by those of ordinary skill in the art that a therapeutically effective amount does not necessarily achieve successful treatment in each specific treatment individual. Instead, a therapeutically effective amount can be an amount that provides a specific desired pharmacological response in a large number of subjects when applied to a patient in need of such treatment. In some embodiments, reference to a therapeutically effective amount can be a reference to an amount measured in one or more specific tissues (e.g., tissues affected by a disease, disorder or condition) or fluids (e.g., blood, saliva, serum, sweat, tears, urine, etc.). It will be understood by those of ordinary skill in the art that, in some embodiments, a specific agent or therapy that can be formulated and / or administered in a single dose is effective. In some embodiments, a therapeutically effective 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 composition of the present invention can be in oral dosage form. 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 ingredients: (a) fillers or solubilizers, such as starch, lactose, sucrose, glucose, mannitol and silicic acid; (b) binders, such as hydroxymethylcellulose, alginates, gelatin, polyvinyl pyrrolidone, sucrose and gum arabic; (c) humectants, such as glycerol; (d) disintegrators, such as agar, calcium carbonate, potato starch or tapioca starch, alginic acid, certain complex silicates and sodium carbonate; (e) disintegrating agents, such as paraffin; (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 lauryl sulfate or mixtures thereof. In capsules, tablets and pills, the dosage form may also contain a buffer. Solid dosage forms, such as tablets, pills, capsules, pills and granules, can be prepared with coatings and shell materials, such as enteric coatings and other materials known in the art. They may contain opacifiers, and the release of active polypeptides or polypeptides in such compositions can be delayed in a certain part of the digestive tract. Examples of embedding components that can be used are polymeric substances and waxes. If necessary, the active polypeptide can also be formed into microcapsules with one or more of the above excipients. Liquid dosage forms for oral administration include pharmaceutically acceptable emulsions, solutions, suspensions, syrups or tinctures. In addition to the active polypeptide, the liquid dosage form 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-butylene glycol, dimethylformamide and oils, especially cottonseed oil, peanut oil, corn germ oil, olive oil, castor oil and sesame oil or mixtures of these substances.

[0015] The provided formulations can include a lyoprotectant, for example, which can be selected from sucrose, lactose, trehalose, dextran, erythritol, arabitol, xylitol, sorbitol, maltose, lactulose, maltulose, glucitol, maltitol, lactitol, isomaltulose and mannitol; amino acids, such as arginine or histidine or 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 formulations may include a penetration enhancer, for example, which may be selected from bile salts, such as trihydroxy salts sodium cholate, sodium glycocholate, sodium taurocholate and dihydroxy salts, sodium deoxycholate, sodium glycodeoxycholate, sodium taurodeoxycholate; fatty acids, their salts and esters, for example, oleic acid, lauric acid, cod liver oil extract, sodium laurate, sodium caprate, monostearate glyceryl, diethylene glycol monoethyl ether and various sucrose fatty acid esters, medium chain fatty acid glycerides, polycaprolactone eoma-3 fatty acids, lecithin (phosphatidylcholine), lysophosphatidylcholine; surfactants, for example, sodium dodecyl (lauryl) sulfate, polysorbate (polysorbate 80), lauryl ether, brijs and benzalkonium chloride; complexing agents, for example, cyclodextrin, dextran sulfate, dextran sulfate, sodium edetate; complexing agents, for example, cyclodextrin, dextran sulfate, sulfate Dextran, sodium edetate, 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, a combination of sodium caprate and alcohol or propylene glycol, a combination of 10% lauric acid in propylene glycol, polyoxyethylene, 2,3-lauryl ether, menthol, sodium caprate, sodium caprylate, sodium glycodeoxycholate, ethylene glycol; polysaccharides such as chitosan and chitosan glutamate; and others It, for example, aprotinin, benzalkonium chloride, cetylpyridinium chloride, cetyltrimethylammonium bromide, sodium salicylate, lysophosphatidylcholine, methoxy salicylate, hydroxymethyloleate, 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] Alternatively or additionally, in some embodiments, the provided formulations can include an absorption enhancer, for example, which can be selected from surfactants, cholesterol, glycerides, salicylates, bile salts, chelating agents, sodium caprate, salts of capric acid and others including N-(5-chlorosalicylic alcohol)-8-aminocaprylic acid (5-CNAC), 4-((4-chloro-2-hydroxybenzoyl))-amino)butyric acid (4-CNAB) and N-(8-(2-hydroxybenzoyl))-amino)caprylic acid, also known as sodium salicylate (SNAC, caprylic acid, C8, castor oil, medium chain, acylcarnitine, EDTA, monolaurin, bovine P-casein, tocopherol succinate glycol chitosan conjugate, lecithin, monostearate (GMS), chitosan and alginate, PLGA, silica, stearic acid, oleic acid, hydrogenated castor oil and trimyristin, etoposide phosphate Sulindac Enalapril Maleate Ramipril Olmesartan Medoxomil Valacyclovir Midodrine Gabapentin Encarbil Sulfasalazine Alternatively or additionally, in some embodiments, provided formulations may include a mucosal bioadhesive, for example, which may be selected from sucrose, lactose, trehalose, dextran, erythritol, arabitol, xylitol, sorbitol, maltose, lactulose, maltulose, glucitol, maltitol, lactitol, isomaltulose and mannitol; amino acids, such as arginine or histidine or 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, mucoadhesive systems, such as from natural Mucoadhesive systems such as gelatin, agarose, chitosan, hyaluronic acid and synthetic polymers such as polyvinyl pyrrolidone (PVP), polyacrylates, polyvinyl alcohol, sodium carboxymethylcellulose (SCMC) and pectin, all anionic polymers, chitosan (cationic) and hydroxypropyl methylcellulose (HPMC) as 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 methacrylate), hydrophilic polymers such as. , methocel K4M, methocel K15M, SCMC 400, Cekol 700, Cekol 10000, CP934P, CP971P and CP974P, carboxyvinyl polymer and triethanolamine, HPC (hydroxypropyl cellulose), CP (Carbopol 934P), Carbopol (CP) Ex-55CMC (sodium carboxymethyl cellulose), HPMC (hydroxypropyl methylcellulose), HEC (hydroxyethyl cellulose), PIP [poly (isoprene)], PIB [poly (isobutylene)], xanthan gum, locust bean gum, pectin, polycarbophil, benzyl esters, hydroxyethyl cellulose, poly (acrylic acid), poly (acrylic acid-co-acrylamide), poly (acrylic acid-co-methyl methacrylate), poly (acrylic acid-co-butyl acrylate), (bioadhesive polymer blend of CP and PIB), formulations consisting of PVP, cetylpyridinium chloride (as stabilizer), chlorinated chitosan, polyethylene oxide, polymethyl vinyl ether / maleic anhydride (PME / MA) and tragacanth gum, polyethylene glycol monomethyl ether monomethacrylate, drum dried waxy corn starch (DDWM), carbopol 974P and sodium stearyl fumarate and cellulose derivatives; hydrogels - acrylic acid (polar) and butyl acrylate (non-polar) and their combinations.

[0018] Besides such inert diluents, the composition may also include adjuvants such as wetting agents, emulsifying and suspending agents, sweetening, flavoring, and perfuming agents.

[0019] In addition to the active polypeptide, the suspension may contain suspending agents, for example ethoxylated isostearyl alcohol, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum methanol and agar, or mixtures of these substances.

[0020] Compositions for parenteral injection may include 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] The dosage forms of the polypeptide of the present invention for topical administration include ointments, powders, patches, sprays and inhalants. The active ingredient is mixed under sterile conditions with a physiologically acceptable carrier and any preservatives, buffers, or propellants that may be required.

[0022] Beneficial Effects

[0023] The present invention provides a polypeptide extracted from a plant and its application in treating hypertension, and specifically provides a highly active antihypertensive polypeptide isolated and prepared from bitter melon peel, the polypeptide having good ACE inhibitory activity. The polypeptide has been confirmed to have good blood pressure lowering effect and safety in a rat hypertension model experiment, and has significant application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The inhibitory effect of each group on ACE DETAILED DESCRIPTION

[0025] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated 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 gourd, wash it with clean water, remove impurities, take 50g of bitter gourd peel and crush it into mud, enzymolyze it for 4 hours under the conditions of a solid-liquid ratio of 1:3 (g:mL), 3% papain, pH 7.0, and an enzymolysis temperature of 58°C, inactivate the enzyme in 95°C boiling water for 10 minutes, cool to room temperature, adjust the pH to 7.0, centrifuge at 9000r / min for 20 minutes, and freeze-dry the supernatant to obtain the bitter gourd peel enzymolysate.

[0028] The ACE inhibition rate IC of the components above 30000, 30000-10000, 10000-6000 and below 6000 from the bitter melon peel hydrolysate was determined by ultrafiltration membranes with relative molecular weight cutoffs of 30000, 10000 and 6000, respectively. 50 , collect the most active components, freeze-dry and store. Among them, the method for determining the ACE inhibition rate is: add 5μL of enzymatic hydrolysate (5mg / mL) and 15μL of ACE (60mU / mL) to a 0.5mL Eppendof tube, keep it at 37°C for 5min, then add 25μL of HHL (7.6mmol / L) and react at 37°C for 25min, add 5μL of 0.1% TFA solution to terminate the reaction, cool to room temperature and filter through a cellulose acetate membrane with a pore size of 0.22mm, and use RP-HPLC to quantify the amount of hippuric acid generated by the reaction of ACE and substrate to determine the ACE inhibitory activity. The ACE inhibition rate calculation formula is ACE inhibition rate = (control hippuric acid peak area - sample hippuric acid peak area) / control hippuric acid peak area x 100%. IC is obtained according to the inhibition rate. 50 The results are shown in Table 1.

[0029] Table 1 IC of each component against ACE 50 value

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

[0031] As can be seen from Table 1, the activity of the intercepted components of each molecular segment increases with decreasing molecular weight. The activity is highest at 6000, and its IC 50 The concentration of 10.13 mg / mL was reached. Therefore, the fraction below 6000 was selected for collection and freeze-dried storage for further separation.

[0032] The components with an activity below 6000 were loaded and eluted using a Sephadex G-25 column at a concentration of 1 g / 10 mL of distilled water. The flow rate was controlled at 2 mL / 10 min, and the samples were automatically collected for detection. The optical density of each collected test tube liquid was measured at a wavelength of 280 nm. Four high protein concentration peaks were obtained by analysis, named A, B, C, and D peaks. The peaks were measured using the aforementioned ACE inhibition rate, and it was found that the inhibitory activity of peak C was the highest. Peak C was then separated and purified by reverse phase high performance liquid chromatography. The mass concentration of the sample separated by the first RP-HPLC was 4 mg / mL, the sample load was 20 μL, and the chromatographic column was Hypersil BDS C 18 (250mmx4.6 mm, 5μm), the mobile phase is 20% acetonitrile containing 0.1% TFA, the flow rate is 1mL / min, the column temperature is 25°C, the detection wavelength is 215nm, the separated components are collected multiple times, and the ACE inhibitory activity is detected after freeze-drying. The component No. 2 with the highest activity is separated for the second time. In the second RP-HPLC separation conditions, except that the mobile phase is 10% acetonitrile containing 0.1% TFA, the other conditions are the same as the first time. The separated components are tested for ACE inhibitory activity here, and the most active component is subjected to mass spectrometry analysis. The highly active antihypertensive polypeptide Sh-CF-5 is obtained by sequence analysis, and its amino acid sequence is shown in SEQID NO: 1.

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

[0034] The antihypertensive peptide Sh-CF-5 was configured into three concentrations of low, medium and high (100 μg / mL, 200 μg / mL and 500 μg / mL, respectively) for ACE inhibition rate identification. Captopril 100 μg / mL was used as a positive control. The blank control group was distilled water. The method for determining the ACE inhibition rate was as follows: 5 μL of peptide and 15 μL of ACE (60 mU / mL) were added to a 0.5 mL Eppendof tube, respectively, and kept at 37°C for 5 minutes, and then 25 μL of HHL (7.6 mmol / L) was added to react at 37°C for 25 minutes, and 5 μL of 0.1% TFA solution was added to terminate the reaction, and after cooling to room temperature and filtering through a cellulose acetate membrane with a pore size of 0.22 mm, RP-HPLC was used to quantify the amount of hippuric acid generated by the reaction of ACE and substrate to determine the ACE inhibitory activity. The calculation formula of ACE inhibition rate is ACE inhibition rate = (control hippuric acid peak area - sample hippuric acid peak area) / control hippuric acid peak area x 100%. The results are as follows Figure 1 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 under high concentration conditions reaches (97.12±1.27)%.

[0036] Example 3 Animal experiment of antihypertensive polypeptide Sh-CF-5

[0037] The male essential hypertensive rats (SHR) used in the experiment were purchased from Changzhou Cavens Experimental Animal Co., Ltd., SPF grade, with a body weight of 220-270g, 12 weeks old, and systolic blood pressure higher than 180mHg. After acclimating to the environment for 3 days, 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, and the experiment was carried out by gavage. The specific dosing conditions are as follows: the blank control group was administered with distilled water and the oral dose was 100 mg / kg; the positive control group was captopril and the oral dose was 40 mg / kg; the low-dose polypeptide group was administered with an oral dose of 40 mg / kg; the high-dose polypeptide group was administered with an oral dose of 100 mg / kg; the experimental animal breeding conditions: the SHR breeding room should be maintained in an SPF-level 12 / 12h light-dark room, the temperature is (22±2)℃, free food and water, the litter is changed every 5 days, and the animals are gavaged once every morning at 8:00-9:00 and evening at 20:00-21:00, for a total of 30 days of dosing. The tail cuff method was used to measure the systolic blood pressure of SHR at 0 days and 30 days after dosing, and each SHR was measured 3 times, and the average value was taken. The results are shown in Table 2.

[0038] Table 2 Systolic blood pressure SBP / mmHg in 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 can be seen from 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), and the low-dose peptide group had a basically similar antihypertensive effect as the positive control group.

[0041] In addition, the effect of the drug on the health of rats was detected by measuring the weight of each rat. After administration, the weight of each group was measured and it was found that the weight of the blank control group increased by (19±4)g, the positive control group increased by (16±2)g, the low-dose polypeptide group increased by (20±5)g, and the high-dose polypeptide group increased by (18±3)g. The weight changes between the groups were not much different, indicating that the oral administration of polypeptides would not damage the normal growth state of SHR. In addition, after the rats in each group were dissected, the physiological states of the heart, liver, and kidneys of the rats in each group were detected 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, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions 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 in that 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 polypeptide Sh-CF-5 in the preparation of a drug for treating hypertension, wherein the amino acid sequence of the polypeptide is shown in SEQ ID NO:

1.

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

5. The use according to claim 4, characterized in that A carrier includes an excipient.

6. The use according to claim 4, characterized in that Carriers include fillers or solubilizing agents.

7. The use according to claim 4, characterized in that The carrier includes a buffering solvent.

8. The use according to claim 4, characterized in that The carrier includes a humectant.

9. The use according to claim 4, characterized in that The carrier includes a disintegrant.

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