CN114835780B - Oligopeptide MEDEI separated from chilli seeds and application thereof in preventing or treating cancers - Google Patents

Abstract

The invention proposes the oligopeptide MEDEI isolated from capsicum seeds and its application in preventing or treating cancer. The oligopeptide is isolated and obtained from capsicum seeds, has anti-tumor effect, can especially effectively inhibit the growth and metabolism of HepG2 cells, and has application prospects it is good.

Description

Oligopeptide MEDEI isolated from pepper seeds and its application in preventing or treating cancer

technical field

The present invention relates to the field of biology. Specifically, the present invention relates to the oligopeptide MEDEI isolated from capsicum seeds and its application in preventing or treating cancer.

Background technique

Capsicum, a herbaceous plant belonging to the Solanaceae family, is native to Mexico and later introduced to China. It is now mainly distributed in Sichuan, Yunnan, Guizhou, Hunan, Henan and other places. Chili is mainly composed of chili pulp and chili seeds. Chili seeds account for 30%-60% of the dry weight of chili peppers and are the main by-products in the processing of chili peppers. Chili seeds are rich in dietary fiber, fat, protein, minerals and vitamin E, etc., and have excellent nutritional and economic value.

With the rapid development of my country's chili processing industry, chili peppers are used in food, medicine, chemical industry and other fields. In the food field, there are more and more chili products such as dried chili, chili sauce, chili powder, hot pot base, and capsaicin is used in medicine. It is also widely used in pepper processing, and a large amount of waste pepper seeds will be produced in the process of pepper processing. At present, a small part of pepper seeds in my country is used as animal feed, but most of them are treated as waste without effective utilization, resulting in environmental pollution and resource waste. Capsicum seeds have high yield, low price, easy access, complete amino acids in meal protein, and moderate essential amino acid content, making them a high-quality protein resource. Therefore, the extraction of bioactive peptides from pepper seeds can not only "turn waste into treasure", improve resource utilization, but also reduce pollution, which is in line with the development goal of an environment-friendly society.

At present, antitumor drugs such as fluorouracil, cisplatin, daunorubicin, etc. play an important role in tumor treatment, but the safety, efficacy, and high price of these drugs limit their clinical application. More and more studies have shown that bioactive peptides from natural foods or animals and plants have positive effects on human health. The physiologically active functions of bioactive peptides are mainly reflected in antibacterial, antiviral, antioxidative, antitumor, hypoglycemic, blood pressure lowering, cholesterol lowering, immune regulation, etc. Animal-derived active peptides have problems such as high cost and safety. Plant-derived active peptides are widely used because of their pure nature and high nutritional value, such as soybean active peptides, peanut active peptides, rapeseed active peptides, etc. However, there are few studies on active peptides in pepper seeds.

SUMMARY OF THE INVENTION

The present invention aims to solve at least one of the technical problems existing in the prior art at least to a certain extent.

In one aspect of the invention, the invention provides an isolated polypeptide. According to an embodiment of the present invention, the isolated oligopeptide has the amino acid sequence shown in SEQ ID NO: 1 or a functional analog thereof, specifically, the amino acid sequence of the isolated oligopeptide is MEDEI (Met-Glu- Asp-Glu-IIE, SEQ ID NO: 1). The inventor isolated and obtained the above-mentioned oligopeptide from pepper seeds, and studied its function, and found that it has anti-tumor effect, especially can effectively inhibit the growth and metabolism of HepG2 cells, and has a good application prospect.

According to an embodiment of the present invention, the isolated oligopeptide is derived from capsicum seeds. The inventors extracted the protein in pepper seeds and discovered the above-mentioned oligopeptides with anti-tumor effect unexpectedly.

In another aspect of the present invention, the present invention provides a nucleic acid molecule. According to an embodiment of the present invention, the nucleic acid molecule encodes the previously described isolated oligopeptide. After the nucleic acid molecule according to the embodiment of the present invention is introduced into a recipient cell, in an environment suitable for protein expression, the isolated oligopeptide described above is expressed, and the oligopeptide has an anti-tumor effect.

It should be noted that the sequence of the nucleic acid molecule is not strictly limited in the present invention, as long as it can encode the isolated oligopeptide described above.

In yet another aspect of the present invention, the present invention provides a construct. According to an embodiment of the present invention, the construct contains the aforementioned nucleic acid molecule. After the construct according to the embodiment of the present invention is introduced into cells, the isolated oligopeptide described above is expressed in an environment suitable for protein expression, which is helpful for exerting the anti-tumor effect of the oligopeptide.

In yet another aspect of the present invention, the present invention provides a recombinant cell. According to an embodiment of the present invention, the recombinant cell contains the aforementioned nucleic acid molecule or the aforementioned construct. Thus, the expression of the aforementioned oligopeptide in an environment suitable for protein expression helps to exert the antitumor effect of the oligopeptide. The recombinant cells of the present invention do not contain germ cells, fertilized egg cells or embryonic cells.

In yet another aspect of the present invention, the present invention provides a medicament. According to an embodiment of the present invention, the drug comprises: the aforementioned isolated oligopeptide, nucleic acid molecule or recombinant cell. Thus, the medicament according to the embodiment of the present invention has the effect of preventing or treating cancer.

In another aspect of the present invention, the present invention proposes the use of the aforementioned oligopeptides, nucleic acid molecules or recombinant cells in the preparation of medicines. According to an embodiment of the present invention, the medicament is for preventing or treating cancer.

According to an embodiment of the present invention, the cancer is breast cancer, lung cancer, nasopharyngeal cancer, liver cancer, stomach cancer, esophageal cancer, colorectal cancer, pancreatic cancer, melanoma, skin cancer, prostate cancer, cervical cancer, leukemia, and thyroid cancer , lymphoma, bladder cancer, kidney cancer, endometrial cancer, ovarian cancer, gallbladder cancer, oral cancer, throat cancer, bone cancer, testicular cancer or brain cancer.

In yet another aspect of the present invention, the present invention provides a method for obtaining the aforementioned isolated oligopeptides. According to an embodiment of the present invention, the method comprises: treating pepper seeds to obtain the isolated oligopeptide.

According to an embodiment of the present invention, the method includes: (1) pulverizing pepper seeds to obtain pepper seed meal; (2) degreasing the pepper seed meal to obtain degreasing pepper seed meal; (3) Extracting the protein in the degreasing pepper seed meal to obtain a crude protein extract; (4) subjecting the crude protein extract to enzymatic hydrolysis treatment, and then inactivating the enzyme to obtain an enzymatically hydrolyzed protein solution; (5) to the The enzymatic protein solution is separated and purified to obtain the separated oligopeptide.

In step (1), by pulverizing the pepper seeds, the subsequent reaction can be better performed, and the reaction is more sufficient, thereby improving the yield and purity of the oligopeptide. In step (2), the degreasing treatment can remove the oil and fat in the pepper seed meal, thereby improving the extraction rate and purity of the protein. In step (4), through enzymatic hydrolysis treatment, the protease can be effectively hydrolyzed into small molecular peptides, which is helpful to obtain oligopeptides with anticancer function.

According to an embodiment of the present invention, in step (1), the pulverized product obtained by the pulverization is passed through a 60-100 mesh sieve to obtain retentate and permeate, and the permeate is collected to obtain pepper seed meal. Thereby, the pepper seed powder can be permeated, impurities can be retained, the protein extraction rate can be improved, and the influence of impurities can be avoided.

According to an embodiment of the present invention, the degreasing solvent used in the degreasing treatment is n-hexane. Thereby, fat can be removed efficiently and it is safe to use.

According to an embodiment of the present invention, step (3) includes: mixing the degreasing capsicum seed meal with water, adjusting the pH of the obtained mixed solution to 9-10 with lye, reacting for 3-5 hours, and then adjusting the reaction solution The pH value is 4~5, the reaction is carried out for 1~3 hours, the reaction solution is centrifuged, the precipitate is collected, and the crude protein extract is obtained. The pH value is high at first because the protein in the pepper seed meal can be dissolved in an alkaline environment, and then the pH is lowered because the protein can settle down at the isoelectric point of the protein, and the separated protein can be obtained after centrifugation.

According to an embodiment of the present invention, before performing the enzymatic hydrolysis treatment in step (4), the crude protein extract is subjected to ultra-high pressure treatment in advance. Ultra-high pressure treatment can improve the physicochemical properties of proteins, and the activity of the products subjected to ultra-high pressure and enzymatic hydrolysis is higher than that of only enzymatic hydrolysis.

According to the embodiment of the present invention, the pressure of the ultra-high pressure treatment is 100-400 MPa, and the time is 20-40 minutes. Thus, it is helpful to improve the physicochemical properties of the protein and increase the activity of the products obtained from enzymatic hydrolysis.

According to an embodiment of the present invention, the temperature of the enzymatic hydrolysis treatment is 30-50° C., the time is 1-5 hours, the pH value is 7-10, and the enzyme used in the enzymatic hydrolysis treatment is selected from alkaline protease, preferably lichen Bacillus, the mass ratio of the enzyme to the crude protein is 1:20 to 1:50. Thus, in order to decompose the protease into small molecular peptides, anticancer oligopeptides can be obtained.

According to an embodiment of the present invention, the inactivation of the enzyme is performed at 90° C. to 100° C. for 1 to 10 minutes. Thereby, in order to inactivate the enzyme, prevent overreaction or prevent the enzyme from interfering with subsequent experiments.

According to an embodiment of the present invention, in step (5), the separation and purification is performed using a chromatographic column, and the chromatographic column is an anion chromatographic column or a hydrophobic chromatographic column; when the chromatographic column is an anion chromatographic column, the The mobile phases used are water and NaCl; when the chromatographic column is a hydrophobic chromatographic column, the mobile phases used are water and 40-60 v/v% methanol solution.

According to an embodiment of the present invention, in step (5), the separation and purification includes: injecting the enzymatic protein solution into an anion chromatography column, eluting with the mobile phase, and collecting the effluent within 35-45 minutes; The liquid is injected into a hydrophobic chromatographic column, the mobile phase is eluted, and the effluent within 75-90 min is collected, so as to obtain a purified product containing the oligopeptide.

The inventors have obtained the above-mentioned preferred separation and purification method through a large number of experiments, whereby the above-mentioned isolated oligopeptide can be obtained.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

Figure 1 shows a schematic diagram of the analysis of the effect of different peptide fragments on the proliferation of HepG2 cells according to an embodiment of the present invention.

Detailed ways

The solution of the present invention will be explained below in conjunction with the embodiments. Those skilled in the art will understand that the following examples are only used to illustrate the present invention, and should not be construed as limiting the scope of the present invention. If no specific technique or condition is indicated in the examples, the technique or condition described in the literature in the field or the product specification is used. The reagents or instruments used without the manufacturer's indication are conventional products that can be obtained from the market.

Example 1

In this embodiment, the oligopeptide MEDEI in capsicum seeds is extracted according to the following method:

1) Deseed: fresh chili seeds and flesh are separated to obtain chili seeds;

2) Crushing: Grind the chili seeds into chili seed meal, pass through an 80-mesh sieve, and obtain chili seed powder;

3) Degreasing: Mix capsicum seed meal and n-hexane at a ratio of 1:10 (g/ml), stir overnight for degreasing, and remove n-hexane by suction filtration after degreasing to obtain capsicum seed meal;

4) Extract protein: Dissolve the defatted pepper seed meal in water at 1:10 (w/v, unit g/mL), adjust the pH of the solution to 9.5 with NaOH solution, dissolve for 4 hours, and then adjust the solution with HCl The pH value was 4.5, precipitated for 2 h, the reaction solution was centrifuged at 8000 rpm for 20 min, and the precipitate was collected as crude protein extract;

5) Ultra-high pressure assisted enzymatic hydrolysis: After the protein isolate was dissolved in water, it was treated with ultra-high pressure at 300 MPa for 30 minutes, and then the product obtained by ultra-high pressure treatment was subjected to enzymatic hydrolysis. The enzyme was Bacillus licheniformis, and the mass ratio of enzyme to substrate was 1: 20 (w/w, unit g/g), the temperature is 40 °C, the pH value is adjusted to 8 with 1 mol/L NaOH, and the time is 3 h;

6) Enzyme inactivation: After the enzymatic hydrolysis, the enzyme was inactivated at 90°C for 10 minutes to obtain a pepper seed enzymatic hydrolyzate solution;

7) Separation and purification of enzymatic hydrolysate: Pass pepper seed enzymatic hydrolysate solution through DEAE anion chromatographic column, the mobile phase is deionized water and NaCl, collect the eluate in the time period of 35~45min, and then use ODS-A reverse phase C18 column (hydrophobic column) separation and purification, the mobile phase is deionized water and 50% methanol, and the eluate in the 75~90min period is collected. The peptides in the obtained eluate were identified and analyzed by mass spectrometry, and multiple pieces of peptide sequence information were obtained.

Example 2

The peptide sequence obtained by mass spectrometry identification and analysis in Example 1 was chemically synthesized to obtain a synthetic peptide. The effect of each peptide on the proliferation of HepG2 cells was studied separately, and the specific steps were as follows:

1) HepG2 cell culture: HepG2 cells are derived from ATCC cell bank, HepG2 cells are cultured in DMEM medium containing 10% FBS, and the growth environment is a 37°C, 5% carbon dioxide cell incubator. Cells were cultured in 25cm ² culture flasks, passaged when the cells were grown to a density of 70%-90%, and the cells were seeded in 96-well plates.

2) Peptide fragment treatment: After culturing cells in a 96-well plate for 24 hours, aspirate the original DMEM medium in the wells, add DMEM containing peptide fragments to each well, and continue to culture for 24 hours at a concentration of 0.1, 0.3, and 0.6 mM. .

3) Measure the cell proliferation rate by MTT method: add 20 μL MTT at a concentration of 5 mg/mL to each well of the 96-well plate, after culturing for 4 hours, aspirate the liquid in each well, add 150 μL DMSO to each well, and measure the absorbance after 20 min of reaction.

The results are shown in Figure 1. It can be seen that compared with other oligopeptides, oligopeptide MEDEI has a better inhibition rate of HepG2 cells, which is helpful for the prevention or treatment of liver cancer.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the present invention. Embodiments are subject to variations, modifications, substitutions and variations.

SEQUENCE LISTING

<110> China Agricultural University

<120> Oligopeptide MEDEI isolated from pepper seeds and its application in the prevention or treatment of cancer

<130>BI3220848

<160> 1

<170> PatentIn version 3.5

<210> 1

<211> 5

<212> PRT

<213> Artificial Sequence

<220>

<223> 1

<400> 1

Met Glu Asp Glu Ile

1 5

Claims (11)

1. An isolated oligopeptide, wherein the amino acid sequence of the isolated oligopeptide is SEQ ID NO: 1.

2. the isolated oligopeptide according to claim 1, wherein the isolated oligopeptide is derived from capsicum seeds.

3. A nucleic acid molecule encoding the isolated oligopeptide of claim 1 or 2.

4. A construct comprising the nucleic acid molecule of claim 3.

5. A recombinant cell comprising the nucleic acid molecule of claim 3 or the construct of claim 4.

6. A medicament, comprising: the isolated oligopeptide of claim 1 or 2, the nucleic acid molecule of claim 3 or the recombinant cell of claim 5.

7. Use of the isolated oligopeptide according to claim 1 or 2, the nucleic acid molecule according to claim 3 or the recombinant cell according to claim 5 for the preparation of a medicament for the prevention or treatment of liver cancer.

8. A method for obtaining an isolated oligopeptide according to claim 1 or 2, comprising:

and (3) processing the pepper seeds to obtain the separated oligopeptide.

9. The method of claim 8, comprising:

(1) crushing the chilli seeds to obtain chilli seed powder;

(2) degreasing the pepper seed powder to obtain degreased pepper seed meal;

(3) extracting protein in the degreased pepper seed meal to obtain a crude protein extract;

(4) carrying out enzymolysis treatment on the crude protein extract, and then inactivating enzyme to obtain an enzymolysis protein solution;

(5) and separating and purifying the enzymolysis protein solution to obtain the separated oligopeptide.

10. The method as claimed in claim 9, wherein in the step (1), the chilli seeds are crushed and then pass through a 60-100-mesh sieve to obtain a retentate and a permeate, and the permeate is collected to obtain chilli seed powder;

in the step (2), a degreasing solvent adopted in the degreasing treatment is n-hexane;

the step (3) comprises the following steps: mixing the degreased pepper seed meal with water, adjusting the pH value of the obtained mixed solution to 9-10 by using alkali liquor, reacting for 3-5 hours, adjusting the pH value of the reaction solution to 4-5, reacting for 1-3 hours, centrifuging the reaction solution, and collecting precipitates to obtain a crude protein extract;

before the enzymolysis treatment in the step (4), performing ultrahigh pressure treatment on the crude protein extract in advance;

the pressure of the ultrahigh pressure treatment is 100-400 MPa, and the time is 20-40 minutes;

the temperature of the enzymolysis treatment is 30-50 ℃, the time is 1-5 hours, and the pH value is 7-10;

the enzyme adopted by the enzymolysis treatment is selected from alkaline protease, and the mass ratio of the enzyme to the crude protein is 1: 20-1: 50;

the enzyme deactivation is carried out for 1-10 min at the temperature of 90-100 ℃;

in the step (5), the separation and purification are carried out by adopting a chromatographic column, wherein the chromatographic column is an anion chromatographic column and a hydrophobic chromatographic column; when an anion chromatographic column is used, the mobile phase used comprises water and NaCl; when a hydrophobic chromatographic column is adopted, the adopted mobile phase comprises water and 40-60 v/v% methanol solution.

11. The method according to claim 9 or 10, wherein the enzyme used in the enzymatic treatment is selected from the group consisting of bacillus licheniformis;

in the step (5), the separation and purification comprises:

injecting the enzymolysis protein solution into an anion chromatographic column, eluting with a mobile phase, and collecting an effluent liquid within 35-45 min;

injecting the effluent into a hydrophobic chromatographic column, eluting by using a mobile phase, and collecting the effluent within 75-90 min so as to obtain a purified product containing the oligopeptide.

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