Application of isorhamnetin in preparation of medicine for preventing and treating cat infectious peritonitis

Abstract

The invention discloses application of isorhamnetin in preparation of a medicine for preventing and treating cat infectious peritonitis. Experiments find that the isorhamnetin can significantly inhibit the proliferation of the feline infectious peritonitis virus on CRFK cells and inhibit the synthesis of NP protein of the feline infectious peritonitis virus, and the inhibitory effect on the feline infectious peritonitis virus is significantly enhanced along with the increase of the drug concentration. Therefore, isorhamnetin can be used for preventing and treating feline infectious peritonitis caused by feline infectious peritonitis virus infection.

Description

Technical Field

[0001] The present invention belongs to the technical field of veterinary drugs, and particularly relates to the application of isorhamnetin in the preparation of drugs for preventing and treating feline infectious peritonitis. Background Art

[0002] Feline Infectious Peritonitis (FIP) is a highly lethal infectious disease caused by the Feline Infectious Peritonitis Virus (FIPV). In 1963, Dr. Holzworth and his team at the Angell Memorial Animal Hospital in Boston, USA, first described FIP as a specific disease, laying the foundation for subsequent research. Since its discovery more than half a century ago, FIP has become one of the most intensively studied feline infectious diseases. In 1978, Pedersen et al. further studied and officially classified FIPV as a coronavirus, clarifying its etiological characteristics. FIPV is mutated from the Feline Coronavirus (FCoV), and FCoV is a member of the genus Alphacoronavirus in the family Coronaviridae. FCoV is subdivided into two serotypes: FCoV-I and FCoV-II. Among them, FCoV-I is the most commonly infected type in cats in nature, while FCoV-II is produced by the recombination of FCoV-I and the Canine Coronavirus (CCoV). These two serotypes differ in genetic and infectious characteristics, but they can both cause FIP. According to pathogenicity, FCoV includes two biotypes: the Feline enteric corona virus (FECV) that infects feline intestinal epithelial cells and FIPV. The virulence of FIPV is much stronger than that of FECV. 60% - 80% of FIP-infected cats die within 1 - 3 weeks after infection, while FECV only causes mild intestinal symptoms. FECV mainly proliferates in intestinal mucosal epithelial cells and mesenteric lymph nodes, while FIPV can infect macrophages and spread to plasma cells, nerve cells, monocytes, and lymphocytes through an immune evasion mechanism, causing a systemic and fatal disease and producing a high titer of progeny virus. Therefore, compared with FECV, FIPV can proliferate more continuously and effectively in various host cells, resulting in more severe pathological reactions.

[0003] Clinically, the diagnosis of FIP is relatively difficult, and it often requires a combination of clinical symptoms, laboratory tests, tissue biopsies and other means to diagnose the affected cats simultaneously. FIPV infection is a serious and often fatal disease with a long treatment cycle, few available drugs, and often poor prognosis. According to different symptoms, FIP can be divided into two major categories: the exudative type and the non-exudative type, and there are some cases that can present both symptoms simultaneously. The exudative type of FIP is also known as the wet type of FIP, and the main characteristic clinical symptom is abdominal and thoracic effusion, with abdominal effusion being the most common. The non-exudative type is also known as the dry type of FIP, and the main clinical symptoms include visual impairment and neurological symptoms such as ataxia, mild paralysis, disorientation, nystagmus, seizures, hypersensitivity, and peripheral neuritis. There is a relatively long subclinical period, and the disease will occur several weeks to several months after infection. In recent years, the incidence of FIP has shown an upward trend, which may be related to factors such as the expansion of the pet trade, the increase in the number of cats raised, and the lack of awareness of FIP among pet owners. Some studies have shown that stress factors may increase the probability of virus replication and spread by causing a decline in immune function, thus inducing the occurrence of FIP. Common stress factors include molting period, long-distance transportation, environmental changes, and new pets. The difficulty in diagnosing FIP and the elusive causative factors have slowed down the research process for treating FIP.

[0004] So far, there are basically no effective therapeutic drugs and vaccines for animal coronaviruses approved for marketing, and most of them are still in the research and development stage. The commonly used GS-441524 and GC-376 in clinical practice are both oily injections, which are corrosive to a certain extent, and are more likely to cause strong pain than ordinary injections. In addition, long-term injection treatment is required, and these characteristics significantly increase the difficulty of clinical medication management. Therefore, the development of new safe and effective drugs is crucial for the prevention and treatment of feline infectious peritonitis.

[0005] To provide more available drug options for the prevention and treatment of feline infectious peritonitis, several compounds with therapeutic effects on feline infectious peritonitis have been disclosed, such as nordihydroguaiaretic acid, glycyrrhizin polysaccharide, compound imipraine, 3,3'-diindolylmethane, and isoliquiritigenin ([1] China Agricultural University. Application of nordihydroguaiaretic acid in the preparation of drugs for inhibiting feline infectious peritonitis virus: CN202410420146.5 [P]. 2024-05-10. [2] Huazhong Agricultural University. Application of glycyrrhizin polysaccharide in the preparation of drugs for anti-feline infectious peritonitis virus: CN202410376670.7 [P]. 2024-06-18. [3] China Agricultural University. Application of imipraine in the preparation of drugs for treating feline infectious peritonitis: CN202410970284.0 [P]. 2024-10-22. [4] Huazhong Agricultural University. Application of 3,3'-diindolylmethane in the preparation of drugs for treating feline infectious peritonitis: CN202210664757.5 [P]. 2023-07-28. [5] Heilongjiang Bayi Agricultural University. Application of isoliquiritigenin in the preparation of drugs for treating feline infectious peritonitis: CN202311492174.X [P]. 2024-03-15.), but the above compounds are still in the research stage, and more drugs for the prevention and treatment of feline infectious peritonitis are still needed for selection.

[0006] Isorhamnetin (CAS: 480-19-3) is one of the most important active ingredients in seabuckthorn fruits and ginkgo leaves, and has a wide range of pharmacological activities such as protecting the cardiovascular and cerebrovascular systems, anti-tumor, anti-inflammatory, antioxidant, protecting organs, and preventing obesity. At present, there is no research report on the inhibition of FIPV by isorhamnetin. Summary of the Invention

[0007] The purpose of the present invention is to overcome the defects and deficiencies of the existing technology in the lack of specific therapeutic drugs for feline infectious peritonitis, and to provide the application of isorhamnetin in the preparation of drugs for the prevention and treatment of feline infectious peritonitis.

[0008] The purpose of the present invention is achieved by the following technical solutions:

[0009] The application of isorhamnetin in the preparation of drugs for the prevention and treatment of feline infectious peritonitis.

[0010] The structural formula of the isorhamnetin is shown in formula (I):

[0011]

[0012] The present invention takes the FIPV type II strain DF-2 as the research object and uses the CRFK cell line as the infection model to explore the effect of isorhamnetin on FIPV infection. Through experimental research, the present invention finds that isorhamnetin can significantly inhibit the synthesis of the NP protein of feline infectious peritonitis virus on CRFK cells, and with the increase of the drug concentration, the inhibitory effect on feline infectious peritonitis virus is significantly enhanced, which can achieve the effect of preventing and treating feline infectious peritonitis caused by feline infectious peritonitis virus infection; moreover, isorhamnetin has good safety and is very suitable for large-scale industrial production and use, which can provide more options for the treatment of feline infectious peritonitis.

[0013] In addition, the isorhamnetin described in the present invention exists in a free form and can form derivatives with media or pharmaceutical carriers commonly accepted in the pharmaceutical field for delivering bioactive compounds to mammals (such as cats). The purpose of the medium is to facilitate the administration of the organism, facilitate better absorption of the active ingredient by the body and then exert biological activity. Biological media usually include body fluids, cells and solutions that artificially simulate the in vivo environment. A pharmaceutically acceptable carrier refers to a substance that does not have pharmacological activity but can help the drug to be effectively delivered, delivered or enhance the drug effect. Pharmaceutically acceptable carriers include, but are not limited to, pharmaceutically acceptable prodrugs, salts, surfactants, dispersants, suspending agents, solvents or emulsifiers, etc.

[0014] The feline infectious peritonitis described is a disease caused by the infection of feline infectious peritonitis virus (feline coronavirus).

[0015] The feline infectious peritonitis virus is feline infectious peritonitis coronavirus (FIPV).

[0016] The drug for preventing and treating feline infectious peritonitis is used to prevent or treat the diseases caused by feline infectious peritonitis virus, relieve the disease symptoms caused by feline infectious peritonitis virus, or delay the development or onset of the diseases caused by feline infectious peritonitis virus.

[0017] The isorhamnetin inhibits the proliferation of feline infectious peritonitis virus and the synthesis of NP protein in feline infectious peritonitis virus.

[0018] Use of isorhamnetin in the preparation of a drug for inhibiting the proliferation of feline infectious peritonitis virus (FIPV) and / or inhibiting the synthesis of NP protein in feline infectious peritonitis virus (FIPV).

[0019] Furthermore, the virus inhibition concentration of rhamnetin on cells is greater than or equal to 10 μM; preferably, the virus inhibition concentration of rhamnetin on cells is (10 - 80) μM; more preferably, the virus inhibition concentration of rhamnetin on cells is (10 - 40) μM. When rhamnetin is applied to animals, the corresponding inhibition concentration can be obtained through conversion.

[0020] Furthermore, the cells include feline kidney cells (CRFK).

[0021] Furthermore, the drug also contains pharmaceutically acceptable excipients. The excipients can be carriers, excipients, diluents, etc.

[0022] Furthermore, substances used as pharmaceutically acceptable carriers include, but are not limited to, natural polymers, synthetic polymers, and inorganic polymers. Among them,

[0023] Natural polymers, such as proteins, hyaluronic acid, natural hydrogels, phospholipids, and cholesterol, etc.; specifically including: liposomes, which are lipid-based carriers composed of a bilayer lipid membrane and can encapsulate water-soluble or lipid-soluble drugs, and are commonly used to improve the stability of drugs and control release; solid lipid nanoparticles, which are made of solid lipid materials, can provide sustained drug release, and are friendly to the skin and target cells; nanoemulsions, which are composed of oil, water, and surfactants, and are commonly used for the delivery of poorly soluble drugs.

[0024] Synthetic polymers, such as synthetic hydrogels, polymeric micelles, polyacid milk, polyglycolic acid, etc.; among them, synthetic hydrogels (including polyvinyl alcohol and polyacrylamide) can provide stable drug release and can be biodegradable in vivo; polymeric micelles are composed of hydrophilic and hydrophobic segments and can encapsulate water-insoluble drugs to improve the solubility and targeting of drugs.

[0025] Inorganic polymers refer to polymers formed by covalent bonding of inorganic elements (such as silicon, boron, aluminum, etc.). Compared with organic polymers, inorganic polymers have stronger chemical stability, higher heat resistance and corrosion resistance. Therefore, they also have important applications in the fields of drug delivery and biomedicine, such as silica, alumina, polymer / metal composites, etc. Among them, alumina is a common inorganic polymer material with strong chemical stability. It is used as a carrier in drug delivery by coating and slow release of drugs through surface modification.

[0026] In addition, pharmaceutically acceptable excipients can also include ethanol, phosphate buffer solution, and other non-toxic and suitable lubricants (such as sodium lauryl sulfate and magnesium stearate), colorants, release agents, coating materials, sweeteners, flavoring agents, fragrances, preservatives, and antioxidants, etc.

[0027] Mixing drug raw materials or drug ingredients with excipients to make a final product suitable for administration, transportation, and storage is called a pharmaceutical preparation, including oral or injectable preparations, such as granules, tablets, aqueous solutions, granules, capsules, powder dispersions, etc. Among them, granules or tablets can be coated or compounded in other ways to provide a dosage form with the advantage of extended action, or through special design, the drug can be slowly released over a longer period of time to achieve a continuous therapeutic effect. For example, compared with conventional release preparations, sustained-release preparations have a slower release rate and can be used for diseases such as feline infectious peritonitis that require long-term action. An enteric coating that regulates drug release according to the solubility of the drug coating will dissolve and release the drug when the drug enters the small intestine with a higher pH value, enabling the drug to be absorbed by the intestine. Commonly used enteric materials include materials such as polyvinyl alcohol, polyacrylic acids, phospholipids, and cellulose acetates.

[0028] Furthermore, pharmaceutically acceptable excipients also include solutions and suspensions in aqueous solvents or organic solvents, or mixtures thereof, which refer to reducing or adjusting the concentration of the drug to an appropriate level by using a certain solvent for the convenience of drug use, absorption, or administration. Dilution is common in liquid drugs, such as injections, oral liquids, etc., or drugs that need to be formulated into a specific concentration.

[0029] Furthermore, the isorhamnetin described above can also be used in combination with other antiviral drugs.

[0030] The present invention has the following advantages and effects compared with the prior art:

[0031] 1. Through experimental research, it is found that isorhamnetin can significantly inhibit the proliferation of feline infectious peritonitis virus and the synthesis of the NP protein of feline infectious peritonitis virus on CRFK cells, and with the increase of drug concentration, the inhibitory effect on feline infectious peritonitis virus is significantly enhanced, and it can achieve the effect of preventing and treating feline infectious peritonitis caused by feline infectious peritonitis virus infection.

[0032] 2. The isorhamnetin in the present invention has good safety. In the concentration range of 1 μM to 80 μM, it has no obvious toxicity to CRFK cells, and the cell survival rate is all above 85%. It is suitable for large-scale industrial production and use, and can provide more options for the treatment of feline infectious peritonitis. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a result diagram of detecting the effect of isorhamnetin on the cell viability of feline kidney cells (CRFK) by the CCK-8 method in Example 1 of the present invention.

[0034] Figure 2This is a statistical chart of the experimental data on the inhibitory effect of isorhamnetin on the proliferation of FIPV mRNA in feline kidney cells (CRFK) in Example 2 of the present invention.

[0035] Figure 3 This is the analysis of the inhibitory effect of isorhamnetin at different concentrations on the synthesis of FIPV NP protein in CRFK cells by immunofluorescence method in Example 3 of the present invention; among them, (A) is the immunofluorescence image; (B) is the statistical chart of the relative expression level of NP.

[0036] Figure 4 This is the analysis of the inhibitory effect of isorhamnetin at different concentrations on the synthesis of FIPV NP protein in CRFK cells by Western Blot in Example 4 of the present invention; among them, (A) is the Western Blot protein blot image; (B) is the statistical chart of the relative expression level of NP. Detailed implementation manners

[0037] The present invention will be further described in detail below in conjunction with examples, but the implementation manners of the present invention are not limited thereto. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field. The test methods without specific experimental conditions specified in the following examples are usually carried out according to conventional experimental conditions or according to the experimental conditions recommended by the manufacturer. Unless otherwise specified, the reagents and raw materials used in the present invention can be obtained through commercial channels.

[0038] The feline infectious peritonitis coronavirus (FIPV) involved in the examples of the present invention is the FIPV type II strain DF-2 (GenBank accession number AFH55129.1), which is purchased from the American Type Culture Collection (ATCC) and passaged and preserved by the College of Veterinary Medicine, South China Agricultural University.

[0039] The CRFK cells and the special culture medium for CRFK cells in the examples of the present invention are purchased from Wuhan Pusaisai Life Science Co., Ltd.

[0040] Example 1 Detection of the cell viability of isorhamnetin in feline kidney cells (CRFK) by CCK-8 assay

[0041] 1. Experimental method

[0042] Resuscitate feline kidney cells (CRFK), resuspend the cells with the special culture medium for CRFK cells (containing 10% (v / v) fetal bovine serum, 100 U / mL penicillin, 100 U / mL streptomycin), and adjust to 7×10 4Cells were inoculated at a density of cells / well into a 96-well plate. Different concentrations of isorhamnetin (640 μM, 320 μM, 160 μM, 80 μM, 40 μM, 20 μM, 10 μM, and 1 μM) were set up. Isorhamnetin was first dissolved in the solvent dimethyl sulfoxide (DMSO), then added to DMEM medium containing 2% (v / v) FBS, and then co-cultured with the cells. A solvent treatment group (added with an equal volume of DMEM medium containing 0.01% (v / v) DMSO and 2% (v / v) FBS) (Vehicle) and a cell control group (without adding any drugs) were added, with 5 biological replicates in each group. The cells were cultured in a 37 °C, 5% CO₂ cell incubator for 24 h. CRFK cell monolayers with a confluence of approximately 80% - 90% in the 96-well plate were treated with different concentrations of isorhamnetin. After 48 h, the supernatant was aspirated, and 100 μL of CCK-8 solution (DMEM culture medium containing 10% (v / v) CCK-8) was added to each well. After continuing to incubate in a 37 °C, 5% CO₂ incubator for 1 h, the absorbance value was measured at 450 nm, and 600 nm was set as the reference wavelength for background correction. The cell viability of each drug was calculated using GraphPad Prism 9.5.0 software.

[0043] 2. Experimental results:

[0044] The experimental results are as Figure 1 shown. Among them, compared with the virus-infected control group, "***" indicates a highly significant difference (P < 0.001). As can be seen from the figure, in the concentration range of 1 μM - 80 μM, the drug isorhamnetin of the present invention has no obvious toxicity to CRFK cells, and the cell viability is all above 85%.

[0045] Example 2 Inhibitory effect of isorhamnetin on the proliferation of FIPV mRNA in feline kidney cells (CRFK)

[0046] 1. Experimental method:

[0047] Feline kidney cells (CRFK) were resuscitated, resuspended with a special medium for CRFK cells (containing 10% (v / v) fetal bovine serum, 100 U / mL penicillin, and 100 U / mL streptomycin), and inoculated at a density of 8×10 5 cells / well into a 24-well plate. High, medium, and low concentration groups of isorhamnetin (concentrations were 40 μM, 20 μM, and 10 μM respectively), a virus group, and a cell control group (without adding any drugs) (the method was the same as in Example 1) were set up, with at least 3 biological replicates in each group. The cells were cultured in a 37 °C, 5% CO₂ cell incubator for 24 h. With 10 TCID 50A monolayer of CRFK cells with a filling degree of about 80% - 90% in a 24-well plate infected with FIPV. After 60 minutes of infection, the supernatant virus solution was aspirated, and isorhamnetin at concentrations of 40 μM, 20 μM, and 10 μM prepared by serial dilution with maintenance medium (DMEM culture medium containing 2% (v / v) fetal bovine serum) was added. Then it was placed in an incubator at 37°C and 5% CO2 and continued to incubate for 24 h and 36 h, after which the culture was terminated.

[0048] After observing the cell morphology, the cell plate was frozen and thawed three times at -80°C and room temperature to fully lyse the cells, causing all the viruses inside the cells to be released into the cell supernatant. Then the supernatant of each well was collected. Using the operating method recommended by the RNA extraction kit (Shanghai Feijie Biotechnology Co., Ltd.), the collected cell supernatant was subjected to RNA extraction. Using the extracted RNA as a template, cDNA was obtained using the operating method recommended by the One Step RT-qPCR Kit (Probe) kit (Hebei Sanshi Biotechnology Co., Ltd.). Primers were designed based on the target gene sequence in the NCBI database and then synthesized by Sangon Biotech (Shanghai) Co., Ltd. In the experiment, the Ct value of the internal reference gene of the cat was used as the internal reference value, and the relative expression of the target gene was calculated according to the formula. Among them,

[0049] The upstream and downstream primer sequences of the FIPV NP gene are as follows:

[0050] FIPV-F: 5’-CGGAATTCATGGCCACACAGGGACAA-3’;

[0051] FIPV-R: 5’-CCCTCGAGTTAGTTCGTAACCTCATC-3’.

[0052] 2. Experimental results:

[0053] The experimental results are as Figure 2 shown. Among them, compared with the virus-infected control group, "***" indicates a highly significant difference (P < 0.001). As can be seen from the figure, after isorhamnetin acts on feline kidney cells (CRFK) for 24 h within the concentration range of 10 μM - 40 μM, it has a highly significant inhibitory effect on the proliferation of FIPV mRNA in CRFK, and shows a good dose-effect relationship.

[0054] Example 3 Analysis of the inhibitory effect of isorhamnetin at different concentrations on the synthesis of FIPV NP protein in CRFK cells by immunofluorescence method

[0055] 1. Experimental method:

[0056] Resuscitate feline renal cells (CRFK), resuspend the cells using a special medium for CRFK cells (containing 10% (v / v) fetal bovine serum, 100 U / mL penicillin, and 100 U / mL streptomycin), and seed the cells at 7×10 4 cells / well in a 96-well plate; set up high, medium, and low concentration groups of isorhamnetin (concentrations are 40 μM, 20 μM, and 10 μM respectively), a virus group, and a cell control group (without adding any drugs) (the method is the same as in Example 1), with 3 biological replicates in each group; culture in a cell incubator at 37 °C and 5% CO2 for 24 h; infect the monolayer of CRFK cells with approximately 80% - 90% confluence in the 96-well plate with 10 TCID 50 of FIPV. After 60 min of infection, aspirate the supernatant virus solution, add isorhamnetin at concentrations of 40 μM, 20 μM, and 10 μM prepared by serial dilution with the maintenance medium (DMEM culture medium containing 2% (v / v) fetal bovine serum), and continue to incubate in a 37 °C and 5% CO2 incubator for 24 h, then terminate the culture.

[0057] Discard the supernatant, wash 3 times with PBS, add 400 μL of 4% paraformaldehyde by mass concentration to each well and fix for 20 min; wash 3 times with PBS, add 100 μL of 0.25% Triton X-100 by mass concentration to permeabilize the membrane, and treat at room temperature for 5 min; add 5% BSA by mass concentration to block non-specific proteins and block at room temperature for 1 h; wash 3 times with PBS, add mouse-derived NP monoclonal antibody (diluted 1:500) (product of Shanghai Bolong Biotechnology Co., Ltd.), and incubate at room temperature for 2 h; wash 3 times with PBS, add the secondary antibody (Alexa 488-labeled anti-mouse IgG, 1:1000) in the dark, incubate at 37 °C in the dark for 1 h, and wash with PBS; observe under a fluorescence microscope, and green fluorescence represents the NP protein of FIPV.

[0058] 2. Experimental results:

[0059] The experimental results are as Figure 3 shown. Among them, compared with the virus-infected control group, "***" indicates a highly significant difference (P < 0.001). As can be seen from the figure, the drug isorhamnetin of the present invention has a significant inhibitory effect on the synthesis of FIPV NP protein in CRFK cells within the concentration range of 10 μM - 40 μM, and shows a good dose-effect relationship.

[0060] Example 4 Western Blot analysis of the inhibitory effect of different concentrations of isorhamnetin on the synthesis of FIPV NP protein in CRFK cells

[0061] 1. Experimental method:

[0062] Resuscitate feline renal cells (CRFK), resuspend the cells with a special medium for CRFK cells (containing 10% (v / v) fetal bovine serum, 100 U / mL penicillin, and 100 U / mL streptomycin), and inoculate 5 at 8×10 50 cells / well into a 12-well plate; set up high, medium, and low concentration groups of isorhamnetin (concentrations are 40 μM, 20 μM, and 10 μM respectively), a virus group, and a cell control group (without adding any drugs) (the method is the same as in Example 1), with 3 biological replicates in each group; culture in a 37°C, 5% CO2 cell incubator for 6 h; infect the monolayer of CRFK cells with approximately 80% - 90% confluence in a 24-well plate with 10 TCID

[0063] of FIPV. After 60 min of infection, aspirate the supernatant virus solution, add isorhamnetin at concentrations of 40 μM, 20 μM, and 10 μM prepared by serial dilution with maintenance medium (DMEM culture medium containing 2% (v / v) fetal bovine serum), and continue to incubate in a 37°C, 5% CO2 incubator for 24 h, then terminate the culture.

[0064] 2. Experimental results:

[0065] The experimental results are as Figure 4 shown. Among them, compared with the virus-infected control group, "***" indicates a highly significant difference (P < 0.001). As can be seen from the figure, within the concentration range of 10 μM - 40 μM, the drug isorhamnetin of the present invention has a significant inhibitory effect on the synthesis of FIPV NP protein in CRFK cells, and shows a good dose-effect relationship.

[0066] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. Use of isorhamnetin in the preparation of a drug for preventing and treating feline infectious peritonitis.

2. The use according to claim 1, wherein: The feline infectious peritonitis is a disease caused by infection with feline infectious peritonitis virus; The feline infectious peritonitis virus is an infectious peritonitis coronavirus.

3. The use according to claim 1, wherein: The drug for preventing and treating feline infectious peritonitis is used to prevent or treat diseases caused by feline infectious peritonitis virus, relieve the symptoms of diseases caused by feline infectious peritonitis virus, or delay the development or onset of diseases caused by feline infectious peritonitis virus.

4. The application according to claim 1, characterized in that: The isorhamnetin inhibits the proliferation of feline infectious peritonitis virus and inhibits the synthesis of NP protein in feline infectious peritonitis virus.

5. Use of isorhamnetin in the preparation of a drug for inhibiting the proliferation of infectious peritonitis coronavirus and / or inhibiting the synthesis of NP protein in infectious peritonitis coronavirus.

6. The application according to claim 1 or 5, characterized in that: The virus inhibitory concentration of the isorhamnetin on cells is greater than or equal to 10 μM.

7. The application according to claim 6, characterized in that: The virus inhibitory concentration of the isorhamnetin on cells is 10 - 40 μM.

8. The application according to claim 7, wherein: The cells include feline kidney cells.

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