CN112274529A

CN112274529A - Application of oyster mushroom polysaccharide selenoside-III anticancer active ingredient in preparation of anti-gastric cancer medicine

Info

Publication number: CN112274529A
Application number: CN202011251768.8A
Authority: CN
Inventors: 钟世安; 王德; 刘慧�; 张云山; 张卓敏; 沈剑
Original assignee: Hunan Wanzhen Biotechnology Co ltd
Current assignee: Hunan Wanzhen Biotechnology Co ltd
Priority date: 2020-02-17
Filing date: 2020-11-11
Publication date: 2021-01-29
Anticipated expiration: 2040-11-11
Also published as: CN112274529B

Abstract

The invention belongs to the technical field of drug development, and particularly discloses oyster mushroom polysaccharide selenoside-III; the invention discloses an oyster mushroom polysaccharide selenoside-III anticancer drug capable of effectively inhibiting gastric cancer and a preparation method thereof. The oyster mushroom polysaccharide selenoside-III anticancer drug can specifically kill gastric cancer cells and promote the metabolism and proliferation of normal cells. Provides a feasible scheme for treating gastric cancer.

Description

Application of oyster mushroom polysaccharide selenoside-III anticancer active ingredient in preparation of anti-gastric cancer medicine

Technical Field

The invention relates to the technical field of medicines, in particular to an active ingredient of oyster mushroom polysaccharide selenoside-III, which can promote the propagation and growth of normal cells and efficiently inhibit gastric cancer cells.

Technical Field

The gastric cancer is the second highest malignant tumor worldwide at present, the death rate is the third highest, and the proportion of Chinese gastric cancer patients is nearly half. In the last two decades, with the development of socioeconomic in China, the change of the dietary habits of people and the gradual increase of the incidence rate of gastric cancer, the physical and psychological health of human beings is seriously threatened. The research on anticancer drugs having specific effects on gastric cancer is very slow.

The early detection rate of the gastric cancer is low, so that the treatment mostly reaches the advanced stage of the gastric cancer. The treatment strategy of the gastric cancer patient in the advanced stage mainly comprises surgical resection, chemotherapy, radiotherapy and other treatment measures, but the prognosis is still poor, and the five-year survival rate is less than 30%. The main reasons are that the existing treatment means have large damage to normal tissues of the body and the tumor is easy to metastasize and spread. Therefore, it is urgent to research a drug which has a specific killing effect on gastric cancer and does not damage normal tissues and cells.

Disclosure of Invention

The invention aims to provide an oyster mushroom polysaccharide selenoside-III anticancer active component (also called polysaccharide selenoside-III) with high anticancer drug effect and low toxic and side effects and application thereof in preparing anti-gastric cancer drugs.

The second purpose of the invention is to provide a medicine for resisting gastric cancer, which contains the oyster mushroom polysaccharide selenoside-III anticancer active ingredient.

The prior art discloses some extraction modes of the polysaccharide selenoside of the oyster mushroom and the effect of the polysaccharide selenoside on oxidation resistance, but the effect of the polysaccharide selenoside of the oyster mushroom on gastric cancer resistance is rarely related in the prior art. In fact, the research of the invention finds that the crude polysaccharide (mixture of various active ingredients) extracted from the oyster mushroom basically has no anticancer activity. However, in the background of research that the crude pleurotus ostreatus polysaccharide has no anticancer activity, there is no motivation in the industry to screen anticancer components from the crude pleurotus ostreatus polysaccharide, however, the present inventors have still found through intensive research that unexpectedly, the selenioside-iii isolated from the crude pleurotus ostreatus polysaccharide has good anti-gastric cancer activity, has no damage to normal cells, and even has good metabolism-promoting and proliferation-promoting effects on normal cells, so the following technical solutions are provided:

an application of Pleurotus Ostreatus polysaccharide selenoside-III in preparing medicine for resisting gastric cancer is provided.

The polysaccharide selenoside-III is a novel polysaccharide compound modified with organic selenium, and the polysaccharide compound is obtained by connecting monosaccharide units in glucose, galactose, mannose, glucuronic acid, galacturonic acid, xylose, glucosamine, fucose, arabinose, ribose and rhamnose through glycosidic bonds;

the hydrolyzed polysaccharide compound has glucose content of above 80%, and galactose, mannose, and glucuronic acid content of above 1%; the content of galacturonic acid, xylose, glucosamine, fucose, arabinose, ribose and rhamnose is not higher than 1%;

preferably, the hydrolyzed heteropolysaccharide compound contains glucose 82-84%, galactose 3-5%, mannose 2.5-3.5%, and glucuronic acid 1-2%; the content of galacturonic acid, xylose, glucosamine, fucose, arabinose, ribose and rhamnose is not higher than 1%.

The research of the invention finds that the polysaccharide selenoside-III of the oyster mushroom has excellent anticancer activity, and not only has no damage to normal cells, but also has good effects of promoting metabolism and proliferation on the normal cells.

As for anticancer drugs, the drugs can inhibit and kill cancer cells and simultaneously can not prevent normal cells from being damaged. However, the inventor further researches on the polysaccharide selenoside-III of the oyster mushroom to find that the polysaccharide selenoside-III not only has good anticancer activity, but also has no damage to normal cells, and even has good metabolism and proliferation promoting effects on the normal cells.

The monosaccharide component analysis shows that the glucose content of the hydrolyzed oyster mushroom polysaccharide selenoside-III exceeds 80 percent, the galactose, mannose and glucuronic acid content exceeds 1 percent, and the monosaccharide composition is obviously different from the polysaccharide or polysaccharide derivative from the existing oyster mushroom, which shows that the oyster mushroom polysaccharide selenoside-III is a newly obtained substance.

Preferably, the molecular weight of the oyster mushroom polysaccharide selenoside-III as an anticancer active component is 13000-18000.

Preferably, the organic selenium is modified in the polysaccharide compound by Se ═ O and Se-C-O;

preferably, the selenium content is 24-26 mu g/g.

The invention also provides a preparation method of the oyster mushroom polysaccharide selenoside-III anticancer active component, which comprises the steps of degreasing selenium-enriched oyster mushroom powder by using an alcohol-water solution, extracting by using water, precipitating by using alcohol and deproteinizing to obtain crude polysaccharide (also called oyster mushroom crude polysaccharide);

separating the crude polysaccharide by a cellulose exchange column, wherein the separation process comprises the steps of sequentially eluting with distilled water, 0.05-0.15 mol/L sodium chloride solution, 0.25-0.35 mol/L sodium chloride solution and 0.45-0.55 mol/L sodium chloride solution;

collecting 0.25-0.35 mol/L sodium chloride solution eluent as a target eluent, desalting, concentrating, and purifying by a sephadex column to obtain the oyster mushroom polysaccharide selenoside-III.

The preparation method of the invention can unexpectedly obtain the oyster mushroom polysaccharide selenoside-III anticancer active ingredient with excellent anticancer activity and no obvious damage to cells through the special elution mechanism.

The conditions of the alcohol-water solution degreasing process are as follows: the alcohol-water solution is an ethanol water solution, and the volume fraction of ethanol is 75-85%; carrying out reflux degreasing;

after degreasing, carrying out solid-liquid separation on the alcohol-water solution, and dispersing and extracting the precipitate in water; the temperature of water extraction is 80-90 ℃;

extracting with water to obtain extractive solution, concentrating, adding ethanol, precipitating with ethanol, and separating solid and liquid to obtain ethanol precipitate;

deproteinizing the alcohol precipitate to obtain crude polysaccharide.

Preferably, the cellulose exchange column is a DEAE-52 cellulose ion exchange column.

Preferably, the target eluate is desalted by dialysis.

Preferably, the sephadex column is a G-100 sephadex column.

Preferably, the use is for the preparation of a medicament against gastric cancer that specifically apoptosis MGC 803.

Further preferably, the use is characterized in that: is used for preparing the anti-gastric cancer medicine which can specifically cause MGC803 cells to die, has no damage to normal cells and even has good effects of promoting metabolism and proliferation on the normal cells.

The oyster mushroom polysaccharide selenoside-III prepared by the invention can effectively kill cancer cells without damaging normal cells, even has good effects of promoting metabolism and proliferation of the normal cells, and has important significance for the research of the oyster mushroom polysaccharide as an anticancer active ingredient on the development of the anticancer field.

The normal cell is preferably a human normal hepatocyte L02.

When the concentration of the polysaccharide selenoside-III anticancer active component is 400 mu g/mL, the cancer cell survival rate is about 60 percent, and the tumor inhibition rate is about 40 percent. When the concentration of the polysaccharide selenoside-III anticancer active component is 600 mug/mL, the survival rate of cancer cells is about 54 percent, and the tumor inhibition rate is about 46 percent.

The invention also provides a medicine for specifically promoting MGC803 cell apoptosis, causing no damage to normal cells and even having good metabolism and proliferation promoting effects on normal cells, which comprises the pharmaceutically effective amount of the oyster mushroom polysaccharide selenoside-III anticancer active component.

Preferably, the anti-gastric cancer medicament specifically promotes MGC803 cell apoptosis without damaging normal cells, even has good metabolism promoting and proliferation promoting effects on normal cells, and also comprises an auxiliary material which is prepared from the pleurotus ostreatus polysaccharide selenoside-III anticancer active ingredient into any pharmaceutically acceptable dosage form.

The pharmaceutically acceptable arbitrary dosage forms comprise powder injection, capsules, dripping pills, granules and the like.

The anticancer activity of the polysaccharide selenoside-III anticancer active component can be quantitatively analyzed by a cck-8 method, and can also be visually analyzed by an AO/EB fluorescent staining method. Acridine Orange (AO) is a selective fluorescent cationic dye that permeates cell membranes and is stained by both living and dead cells. Observing under a fluorescence microscope, wherein acridine orange can permeate through a complete cell membrane to stain the cell nucleus of a living cell into uniform green fluorescence; the apoptotic cell is condensed or broken into fragments with different sizes due to chromatin, and the acridine orange stains the cell nucleus into yellow green bright green fluorescence; dead cells fluoresce orange, but the fluorescence is weak and even disappears. Ethidium Bromide (EB) stains only cells with an incomplete cell membrane, AO stains necrotic cells orange or red-orange in combination with EB, but this also includes cells with a morphology similar to viable nuclei and without chromatin condensation. Therefore, the AO/EB staining kit can distinguish normal cells, apoptotic cells and necrotic cells. According to the invention, by means of AO/EB staining, it can be observed that polysaccharide selenoside-III anticancer active component can specifically make MGC803 cell die, and has no obvious damage to normal cell.

Advantageous effects

1. The invention unexpectedly discovers that the oyster mushroom polysaccharide selenoside-III not only has good anticancer activity, but also can solve the problem that the existing anticancer active ingredients damage normal cells.

2. The invention can obtain the oyster mushroom polysaccharide selenoside-III which has good anticancer activity and no obvious toxic or side effect on normal cells by the preparation method.

Drawings

FIG. 1 is an infrared spectrum (758 cm) of polysaccharide selenoside-III component of Pleurotus Ostreatus^-1The peak is Se ═ O characteristic peak, 660cm^-1Peak of (A) is Se-C-O bond

FIG. 2 is a Gel Permeation Chromatography (GPC) chart of selenoside-III fraction of Pleurotus ostreatus polysaccharide

FIG. 3 shows the fiber column elution profile of Pleurotus ostreatus crude selenium polysaccharide (three fractions eluted with 0, 0.1, 0.3mol/L aqueous sodium chloride solution, named selenoside I, fraction II, fraction III)

FIG. 4 shows selenium content (ICP) of polysaccharide selenoside-III of Pleurotus ostreatus

FIG. 5 elution profiles (HPLC) of selenoside-III hydrolysate of Pleurotus ostreatus polysaccharide and reference monosaccharide

FIG. 6 Transmission Electron Microscopy (TEM) of selenosugar-III polysaccharide

FIG. 7 shows the survival rate of gastric cancer cells (MGC803) after incubation of the Pleurotus ostreatus selenoside-III fraction

FIG. 8 is a fluorescent photograph of gastric cancer cells (MGC803) after incubation of the polysaccharide selenoside-III fraction of Pleurotus ostreatus, stained with AO/EB. (Picture taken by high connotation, 40 ×)

FIG. 9 is a flow chart of gastric cancer cells (MGC803) stained with annexin V-FITC/PI apoptosis detection kit after polyselenoside-III incubation

FIG. 10 shows the scratching test of gastric cancer cells (MGC803) after incubation of selenosugaride-III

FIG. 11 survival Rate of gastric cancer cells (MGC803) after incubation with crude polysaccharide of Pleurotus Ostreatus

FIG. 12 survival of Normal cells (L02) after incubation with the Pleurotus Ostreatus polysaccharide selenoside-III fraction

FIG. 13 is a fluorescent photograph of normal hepatocytes (L02) after incubation with the polysaccharide selenoside-III fraction of Pleurotus ostreatus after AO/EB staining. (Picture taken by high connotation, 40 ×)

FIG. 14 is a cytoflow chart of L02 after incubation of selenosugaride-III, staining with annexin V-FITC/PI apoptosis detection kit

FIG. 15 shows the scratch test of gastric cells (L02) after polyselenide-III incubation

FIG. 16 survival Rate of Normal cells (L02) after incubation with crude polysaccharide of Pleurotus Ostreatus

Detailed Description

The following examples are intended to illustrate the invention without further limiting it.

Example 1

Preparation of crude selenium polysaccharide

Taking 15g of selenium-rich oyster mushroom powder (provided by Wanzhen biological science and technology Co., Ltd., Hunan), adding 120mL of 80% ethanol-water solution, stirring and refluxing at 65 ℃ for 3h, performing suction filtration to obtain a filter cake, and drying.

Water extraction: 10g of the filter cake was put into a flask, 300mL of ultrapure water was added thereto, and the mixture was stirred at 85 ℃ for 3 hours, centrifuged, and the supernatant was concentrated to obtain a viscous liquid.

Alcohol precipitation: dripping 4 times of anhydrous ethanol into the viscous liquid, standing at 4 deg.C for 24 hr, and centrifuging to obtain precipitate.

Deproteinization: dissolving the precipitate in 100mL of water, adding a quarter volume of sevage reagent, centrifuging to obtain a supernatant, repeating for 6 times, dialyzing with a dialysis bag, and lyophilizing to obtain crude polysaccharide (also called oyster mushroom crude polysaccharide or crude selenium polysaccharide).

(II) refining selenium polysaccharide

(2.1) ion exchange column purification process: DEAE-52 cellulose ion exchange column was used to purify the polysaccharide, and 300mg of the sample (crude polysaccharide from step (I)) was dissolved in 10mL of water and wet loaded. Then, the mixture is sequentially eluted by distilled water and 0.1, 0.3 and 0.5mol/L sodium chloride solution in a gradient way. Detecting polysaccharide content with phenol-sulfuric acid method at 490nm, isolating with tube, drawing elution curve chart, and collecting main components. Three components are separated out, and the component eluted by 0.3mol/L sodium chloride water solution is taken as the component 3.

(2.2) dialysis: the sample-water solution (fraction 3 of step (2.1)) was concentrated to 10-15mL with a rotary evaporator, then the pH was adjusted to 7 with hydrochloric acid solution, dialyzed against deionized water for 36h, then concentrated to 5 mL.

(2.3) glucan column purification Process: and (3) purifying the component 3 (dialysis component in the step (2.2)) by using G-100 glucan, carrying out wet-process sample loading on 5mL of sample, eluting with deionized water, detecting by using a phenol-sulfuric acid method separation tube, concentrating, and freeze-drying to obtain the refined polysaccharide selenoside-III of the oyster mushroom.

Hydrolysis and monosaccharide component analysis of oyster mushroom polysaccharide selenoside-III: precisely weighing the sample into a 5mL ampoule bottle, adding 2.0mL (2mol/L) of trifluoroacetic acid into the 5.0mL ampoule bottle, sealing the tube, and carrying out acidolysis at 110 ℃ for 8 h. Taking out and volatilizing trifluoroacetic acid, and adding 2.0mL of water for redissolving to finish hydrolysis. Then, 250. mu.L of the hydrolyzed solution was precisely pipetted into a 5mL EP tube, and 250. mu.L (0.6mol/L) of sodium hydroxide and 500. mu.L (0.4mol/L) of a methanol solution of 1-phenyl-3-methyl-5-pyrazolone were added and reacted at 70 ℃ for 1 hour. Cooling in cold water for 10 min; adding 500 μ L (0.3mol/L) hydrochloric acid for neutralization, adding 1mL chloroform, whirling for 1min, centrifuging at 3000r/min for 10min, carefully taking supernatant, and extracting for 3 times. And taking the supernatant to complete derivatization. The reference sample was a sugar mixed solution containing 50. mu.g/mL of each comparative sugar, and was derivatized under the same conditions. And finally, eluting the sample and the reference substance by using an XTimate C18 high performance liquid phase device, recording an elution curve, and calculating the monosaccharide component by using the peak area ratio of the sample to the reference substance (eluent is 0.05M potassium dihydrogen phosphate solution with pH value of 6.7-acetonitrile of 83-17). The analysis results of monosaccharide components thereof are shown in Table 1 and FIG. 5.

TABLE 1 Pleurotus ostreatus polysaccharide selenoside-III constituent monosaccharide content

The oyster mushroom polysaccharide selenoside-III obtained in example 1 is used for the following anticancer and normal cytotoxicity researches:

example 2

Pharmacodynamic test of polysaccharide selenoside-III (obtained in example 1) on human gastric cancer cells

When MGC803 cell density reaches 80-90%, trypsinize until cell rounding, and then add cell culture medium to stop digestion. The cell suspension was diluted appropriately and counted in a hemocytometer, plated at 8000 cells per well density (96 well plate), and the 96 well plate was placed in a cell incubator for 24 h.

The culture medium in the 96-well plate was then replaced with serum-free cell culture medium and incubated in a cell incubator for 24 h.

The previous serum-free medium was replaced with cell culture medium containing different concentrations of polyselenide-III (0. mu.g/mL, 50. mu.g/mL, 100. mu.g/mL, 200. mu.g/mL, 400. mu.g/mL, 600. mu.g/mL) and incubated for 24 h. And cell-free, simple cell culture fluid was used as a negative control.

10 μ L of cck-8 reagent was added to each well, and after incubating for 2 hours, absorbance OD was measured at 450nm with a microplate reader, and the cell survival rate was calculated.

Cell survival rate ═ OD_{Experimental group}-OD_{Negative control group})/(OD_{Blank group}-OD_{Negative control group})。

Plates were plated at 5000 cells per well (96 well plates) and the 96 well plates were incubated in a cell incubator for 24 h. The culture medium in the 96-well plate was then replaced with serum-free cell culture medium and incubated in a cell incubator for 24 h. The previous serum-free medium was replaced with cell culture medium (0. mu.g/mL, 300. mu.g/mL, 600. mu.g/mL) containing different concentrations of polyselenide-III and incubated for 24 h. Wash with PBS and add 90 μ L PBS, 5 μ L OA solution and 5 μ L EB solution, stain for 5min, then wash with PBS and observe under high connotation (AO excitation 488nm, emission 515nm, EB excitation 518nm, emission 605 nm).

Apoptosis was then quantified by flow cytometry at 5 × 10 per well⁵Density plates (6 well plates) and incubation for 24 h. The medium was refreshed with cell culture medium (0. mu.g/mL, 300. mu.g/mL, 600. mu.g/mL) containing different concentrations of polyselenide-III drug and incubated for 24 h. Then staining with annexin V-FITC/PI apoptosis detection kit, digesting and collecting cells, and detecting on a flow cytometer.

The scratch test was used to verify the effect of the drug on the ability of the cells to migrate at 1X10 per well⁶The cells are inoculated at the cell density of (1), cultured for 24 hours for adherence, then scratched by a 200-mu L tip, cultured for 0, 12 hours, 24 hours and 48 hours in a serum-free medium containing the medicine, and then observed under a fluorescence inverted microscope.

After MGC803 cells were incubated with polyselenide-III for 24h, the cell viability was about 54%, i.e., the tumor suppression rate could reach 56%, at a concentration of 600. mu.g/mL (as shown in FIG. 7). This can be shown positively that polyselenide-III is effective in inhibiting gastric cancer cells. As shown in fig. 8, from the AO/EB staining results, MGC803 cells incubated without drug did not show significant apoptotic signals, and as the administration concentration increased, the EB channel fluorescence was significantly enhanced and apoptotic cells significantly increased, which more intuitively indicates that selenoside-iii polysaccharide can effectively induce gastric cancer cell apoptosis. As shown in FIG. 9, when the administration concentration was 600. mu.g/mL, the proportion of apoptotic cells was 39.16%. As shown in FIG. 10, the recovery ability of the scratch gradually decreased with the increase of the administration concentration, and the result proved that polyselenide-III could inhibit the migration ability of tumor cells to some extent.

Comparative example 1:

pharmacodynamic experiment of oyster Mushroom crude polysaccharide (crude polysaccharide product obtained in step (I) of example 1 without column purification) on human gastric cancer cells

The previous serum-free medium was replaced with cell culture medium (0. mu.g/mL, 50. mu.g/mL, 100. mu.g/mL, 200. mu.g/mL, 400. mu.g/mL, 600. mu.g/mL) containing varying concentrations of crude polysaccharide from Pleurotus ostreatus and incubated for 24 h. And cell-free, simple cell culture fluid was used as a negative control.

As shown in fig. 11, after MGC803 cells were incubated with crude pleurotus ostreatus polysaccharide for 24 hours, the survival rate of the cells increased within a small range with the increase of the administration concentration, which demonstrates to some extent that the crude pleurotus ostreatus polysaccharide had no significant inhibitory effect on gastric cancer cells.

Example 3

Pharmacodynamic test of polysaccharide selenoside III (example 1) on Normal cells

When the density of normal human liver cells reaches 80-90%, the cells are digested with pancreatin until the cells become round, and then a cell culture solution is added to stop the digestion. The cell suspension was diluted appropriately and counted in a hemocytometer, plated at 8000 cells per well density (96 well plate), and the 96 well plate was placed in a cell incubator for 24 h.

Scratch test to verify the effect of drug on cell migration ability, at 1 × 10 per well⁶The cells are inoculated at the cell density of (1), cultured for 24 hours for adherence, then scratched by a 200-mu L tip, cultured for 0, 12 hours, 24 hours and 48 hours in a serum-free medium containing the medicine, and then observed under a fluorescence inverted microscope.

As shown in FIG. 12, when L02 normal cells were incubated with polyselenide-III, the cell survival rate reached 150% at the administration concentration of 400. mu.g/mL, and the cell proliferation rate was greatly increased relative to that of the normal cells without administration. As shown in FIG. 13, no significant apoptosis or dead cells were observed at increased concentrations following AO/EB staining. As shown in FIG. 14, the flow cytometry results showed that the proportion of apoptotic cells was less than 4% at a dosing concentration of 600. mu.g/mL, thus demonstrating that polyselenide-III has no significant toxic side effects on normal cells. As shown in FIG. 15, the migration ability of normal cells incubated with polyselenide-III was not significantly changed, so that the migration ability of the fraction on normal cells was not significantly affected. The above data indicate that the polysaccharide selenoside-III has no obvious damage effect on normal liver cells.

Comparative example 2:

pharmacodynamic experiment of oyster Mushroom crude polysaccharide (crude selenium polysaccharide obtained in step one of example 1) on Normal cells without column purification

When the density of the human normal cells reaches 80-90%, the cells are digested by pancreatin until the cells become round, and then a cell culture solution is added to stop the digestion. The cell suspension was diluted appropriately and counted in a hemocytometer, plated at 8000 cells per well density (96 well plate), and the 96 well plate was placed in a cell incubator for 24 h.

As shown in fig. 16, after L02 normal cells were incubated with crude polysaccharide of pleurotus ostreatus for 24h, there was no significant change in cell survival rate after co-incubation with the drug, which demonstrates to some extent that the crude polysaccharide of pleurotus ostreatus has neither inhibitory nor proliferation-promoting effects on normal cells.

Claims

1. The application of an anticancer active ingredient of oyster mushroom polysaccharide selenoside-III in preparing a medicine for resisting gastric cancer is characterized in that: the anticancer active ingredient of the oyster mushroom polysaccharide selenoside-III is a heteropolysaccharide compound modified with organic selenium; the heteropolysaccharide compound is obtained by connecting monosaccharides including glucose, galactose, mannose, glucuronic acid, galacturonic acid, xylose, glucosamine, fucose, arabinose, ribose and rhamnose through glycosidic bonds;

in the hydrolyzed heteropolysaccharide compound, the content of glucose exceeds 80%, and the content of galactose, mannose and glucuronic acid exceeds 1%; the content of galacturonic acid, xylose, glucosamine, fucose, arabinose, ribose and rhamnose is not higher than 1%;

2. The use of the polysaccharide selenoside-III anticancer active ingredient of claim 1, wherein: the molecular weight is 13000-18000;

preferably, the selenium content is 24-26 mu g/g.

3. The use of the polysaccharide selenoside-III anticancer active ingredient of Pleurotus ostreatus as claimed in claim 1 or 2 wherein: the preparation process of the oyster mushroom polysaccharide selenoside-III anticancer active component comprises the following steps:

degreasing selenium-enriched oyster mushroom powder by using an alcohol-water solution, extracting with water, precipitating with ethanol, and deproteinizing to obtain crude polysaccharide;

collecting 0.25-0.35 mol/L sodium chloride solution eluent as a target eluent, desalting, concentrating, and purifying by a sephadex column to obtain the pleurotus ostreatus polysaccharide selenoside-III.

4. The use of the polysaccharide selenoside-III anticancer active ingredient of claim 3, wherein: the conditions of the alcohol-water solution degreasing process are as follows: the alcohol-water solution is an ethanol water solution, and the volume fraction of ethanol is 75-85%; carrying out reflux degreasing;

deproteinizing the alcohol precipitate to obtain crude polysaccharide.

5. The use of the polysaccharide selenoside-III anticancer active ingredient of claim 3, wherein: the cellulose exchange column is a DEAE-52 cellulose ion exchange column;

preferably, desalting treatment is carried out on the target eluent by adopting a dialysis means;

preferably, the sephadex column is a G-100 sephadex column.

6. The use of the polysaccharide selenoside-III anticancer active ingredient of Pleurotus ostreatus as claimed in any one of claims 1 to 5, wherein: can be used for preparing medicine for specifically apoptosis MGC803 and resisting gastric cancer.

7. The use of the polysaccharide selenoside-III anticancer active ingredient of claim 6, wherein: is used for preparing the anti-gastric cancer medicine which can specifically cause MGC803 cells to die, has no damage to normal cells and even has good metabolism and proliferation promoting effects on the normal cells.

8. The use of the polysaccharide selenoside-III anticancer active ingredient of claim 7, wherein: the normal cell is a normal hepatocyte L02.

9. A specific anti-MGC 803 apoptosis anti-gastric cancer drug characterized by: comprising a pharmaceutically effective amount of the polysaccharide selenoside-III anticancer active ingredient of oyster mushroom according to any one of claims 1 to 8.

10. The medicament of claim 9, further comprising an adjuvant for formulating the active anticancer Pleurotus ostreatus selenoside-III ingredient into any pharmaceutically acceptable dosage form.