KR20130076558A - Composition having antibacterial or antiviral activity containing sorghum natural colors extract or polyphenol compound separated from it - Google Patents

Abstract

PURPOSE: A composition containing a natural pigment extract of sorghum or polyphenol compounds such as apigenin, apigeninidine, luteolin, and luteolinidine is provided to suppress neuraminidase activity, and to be used as a pharmaceutical product, a food additive, or a feed additive with antibacterial or antiviral activity. CONSTITUTION: A pharmaceutical composition as an antibacterial agent or an antiviral agent contains a natural pigment extract of sorghum and suppresses neuraminidase. The pharmaceutical composition contains one or more kinds of polyphenol compounds selected among apigenin of chemical formula 1, apigeninidine of chemical formula 2, luteolin of chemical formula 3, and luteolinidine of chemical formula 4. A food additive with antibacterial or antiviral activity contains the one or more kinds of polyphenol compounds as active ingredients. A method for preparing the extract comprises the step of extracting sorghum powder with a methanol solvent containing 0.1-1% of hydrochloric acid at 5-40 deg. C.

Description

Composition having antibacterial or antiviral activity containing sorghum natural colors extract or polyphenol compound separated from it}

The present invention relates to a composition having an antibacterial or antiviral activity comprising a sorghum natural pigment extract or a polyphenol compound isolated therefrom, and more particularly, an api which is a sorghum natural pigment extract or a polyphenol compound isolated from the extract. Since genine, apigeninidine, luteolin, and luteolinidine have neuraminidase enzyme inhibitory activity, antibacterial or antiviral agents may be included as an active ingredient by using the above-mentioned natural pigment of sorghum or the polyphenol compound isolated from the extract. A composition for use in pharmaceuticals, food additives or feed additives having activity.

Influenza virus is one of the world's most common viruses affecting both humans and livestock. It is an acute respiratory infection that develops with a rapid incubation period, causing severe systemic symptoms such as systemic boredom, headache, back pain, and muscle pain. Causes respiratory symptoms, including a runny nose.

Influenza viruses are RNA enveloped viruses having a particle size of about 125 nm in diameter. Influenza viruses basically consist of an internal nucleocapsid or core of ribonucleic acid (RNA) bound to a nucleoprotein surrounded by a viral envelope having a lipid bilayer structure and an outer glycoprotein. The inner layer of the viral envelope consists mainly of matrix proteins, and the outer layer consists mostly of host-derived lipid material. Influenza viruses include two surface antigens, glycoprotein neuraminidase (NA) and hemagglutinin (HA), which appear as spikes of 10-12 nm long at the surface of the particles. It is this surface protein, in particular hemagglutinin, that determines the antigenic specificity of the influenza subtype. Virus strains are of origin, type of subterranean site and year of isolation, serial numbers and influenza viruses are classified as type A, type B, or type C.

For influenza type A, hemagglutinin and neuraminidase are used as major distinguishing means, and they are called H type antigen and N type antigen, respectively. Currently, 16 types of H-type antigens are known (H1-H16), and 9 types of N-type antigens are known (N1-N9). The notation is H3N2, H5N1, etc. In the case of B and C viruses, since the mutation does not occur as fast as A, do not use this means of discrimination.

Influenza viruses usually cause pandemics almost every winter with an infection rate of type A or B virus as high as 40% over a period of more than six weeks. Especially in the developed world, elderly people aged 65 or older, accounting for 80-90% of all influenza-related deaths, are vulnerable. Individuals with chronic illnesses are also more likely to experience these complications and infants may have serious illnesses. In early 2009, the virus was invented in Mexico, but the epidemic spreaded rapidly across the US and Canadian borders, and now new cases are reported in almost all countries around the world.

Sorghum containing functional bioactive substances is rich in plant compounds such as tannins, phenols, anthocyanins, phytosterols and policosanols, and known sorghum polyphenolic compounds have antioxidant, anti-obesity, anti-diabetic, anti-inflammatory activity, (hyperlipidemia prevention) Etc.) Activity such as useful action for cardiovascular health is known until this time. In addition, the polyphenol compound may be applied for the prevention and treatment of influenza virus infection by inhibiting neuraminide enzyme.

Neuraminidase refers to an enzyme that separates sialic acid by hydrolyzing neuramic acid. It is found in viruses, bacteria, protozoa, lactic trichomonas (Trichomonas foetus), and animal organs. Influenza virus, Vibrio choleroe, Clostridium perfringens, and the like have high purity crystallized enzymes, and are used as reagents useful in the study of the structure and function of complex sugars. In viruses, they exist on the surface of myxoviruses and paramyxoviruses. It acts when these viruses spill out of red blood cells or normal cells, and is also called a receptor destroying enzyme. It is not known what role this enzyme plays during the course of normal infection. The antigenicity of this enzyme varies depending on the influenza virus type or the virus of the parainfluenza group, and is an indicator of the classification of the virus depending on its presence. Neuraminidase is an influenza virus surface antigen and plays an important role in releasing the newly generated virus out of the cell. Therefore, studies are currently underway in Korea to develop a composition for inhibiting neuraminidase as a treatment for influenza virus.

Conventional neuraminidase inhibitor relates to sorghum extract having antimicrobial activity and its use in Korean Patent Publication No. 2010-0122543, antimicrobial cosmetic composition, antimicrobial pharmaceutical composition, antimicrobial food containing sorghum extract as an active ingredient A method of preparing sorghum extract applicable as an additive has been proposed. In addition, Korean Patent Application Publication No. 2010-0114674 proposes a pharmaceutical composition capable of inhibiting the activity of neuraminidase and a xanthone-based compound isolated from Cucumis japonica extract or fraction and preventing and treating influenza virus infection disease.

Therefore, much research is needed on improved compositions and methods for treating influenza and there is a need for compositions that have a broad range of immunogenicity against seasonal influenza species and newly emerging influenza species recommended by the WHO. Accordingly, there is an urgent need to develop new materials for neuraminidase inhibitors used as therapeutic agents for influenza virus.

Accordingly, an object of the present invention is to provide a pharmaceutical composition comprising as an active ingredient a sorghum natural pigment extract having an antibacterial or antiviral related neuraminidase enzyme inhibitory activity or a polyphenol compound isolated from the extract.

It is also an object of the present invention to provide a food additive comprising as an active ingredient a sorghum natural pigment extract having an antibacterial or antiviral related neuraminidase enzyme inhibitory activity or a polyphenol compound isolated from the extract.

It is also an object of the present invention to provide a feed additive comprising a natural sorghum extract having an antibacterial or antiviral related neuraminidase enzyme inhibitory activity or a polyphenol compound isolated from the extract.

It is also an object of the present invention to provide an extraction method for obtaining sorghum natural pigment extract from sorghum.

In order to solve the above problems, the present invention is an apigenin, apigeninidine, luteolin, and luteolinidine isolated from sorghum natural pigment extract or sorghum natural pigment extract as an active ingredient It provides a pharmaceutical composition having an antibacterial or antiviral activity.

In addition, the present invention is a food additive having an antibacterial or antiviral activity comprising at least one polyphenol compound selected from apigenin, apigeninidine, luteolin, and luteolinidine isolated from sorghum natural pigment extract as an active ingredient. To provide.

In addition, the present invention is a feed additive having an antibacterial or antiviral activity comprising at least one polyphenol compound selected from apigenin, apigeninidine, luteolin, and luteolinidine isolated from sorghum natural pigment extract as an active ingredient. To provide.

The present invention also provides a method for producing a natural sorghum extract obtained by extracting sorghum powder with a methanol solvent containing 0.1 to 1% hydrochloric acid at a temperature of 5 to 40 ℃.

According to the present invention, there is an effect that can be applied as a composition for the prevention and treatment of influenza virus.

In addition, the sorghum natural pigment extract can be used to inhibit the activity of neuraminidase and the related diseases.

It can also be applied as a food additive or animal feed additive using a composition containing an active ingredient that inhibits neuraminidase enzyme activity related to antibacterial or antiviral activity.

1 is a chemical structure of a compound isolated from sorghum natural pigment extract.
2A, 2B, 2C and 2D are the ¹ H NMR and ¹³ C NMR spectra of polyphenol compounds isolated from sorghum.
FIG. 3 is a graph showing the neuraminidase enzyme activity inhibitory concentration (IC ₅₀ ) of polyphenol compounds isolated from sorghum.
Figure 4 is a graph showing the amount of active ingredient extract according to the alcohol solvent.
5 is a graph showing the amount of effective ingredient extraction with methanol or acid added methanol.
6 is a graph showing the amount of active ingredient extraction according to the extraction time.
7 is a graph showing the amount of active ingredient extracted according to the extraction temperature.

The present invention is a sorghum extract, or apigenin represented by the formula (1) isolated from the sorghum extract, apigeninidine represented by the formula (2), luteolin represented by the formula (3), and luteolini represented by the formula (4) Provided are compositions having antibacterial or antiviral activity comprising at least one polyphenol compound selected from the group as an active ingredient.

[Formula 1]

[Formula 2]

(3)

[Formula 4]

At this time, the polyphenol compound is preferably a composition for preventing and treating influenza virus by inhibiting the activity of neuraminidase.

In addition, the present invention provides a food additive having an antibacterial or antiviral activity comprising at least one polyphenol compound selected from apigenin, apigeninidine, luteolin, and luteolinidine isolated from sorghum natural pigment extract. to provide.

In addition, the present invention provides a feed additive having an antibacterial or antiviral activity comprising at least one polyphenol compound selected from apigenin, apigeninidine, luteolin, and luteolinidine isolated from sorghum natural pigment extract. to provide.

The natural sorghum extract of the present invention includes water, ethanol, lower alcohols having 1 to 3 carbon atoms such as ethanol and methanol, mixed solvents thereof, or extracted with a solution containing 0.1 to 1% hydrochloric acid. It is possible to extract, preferably with 70 to 100% methanol or methanol containing hydrochloric acid.

After milling the sorghum seeds of the present invention, the extractant has a volume of about 2 to 15 times the weight of the sorghum sample, preferably about 5 to 10 times, about 1 to 3 days, preferably 12 to 72 hours. Using a method such as hot water extraction, cold needle extraction, reflux cooling extraction or ultrasonic extraction for 24 hours, preferably hot water extraction, and preferably filtered and concentrated to obtain a sorghum extract for 24 hours. The sorghum may include golden sorghum, myro sorghum, white sorghum and the like.

Pharmaceutical dosage forms of one or more polyphenolic compounds selected from apigenin, apigeninidine, luteolin and luteolinidine isolated from the extract of the present invention may also be used in the form of their pharmaceutically acceptable salts.

The pharmaceutical compositions of the present invention may be used in the form of oral dosage forms, external preparations, suppositories, and sterile injectable solutions, such as powders, granules, tablets, capsules, suspensions, emulsions, syrups, and aerosols, respectively, according to conventional methods. However, the present invention is not limited thereto and may be appropriately adjusted depending on the method of use and use. Carriers, excipients and diluents that may be included in the pharmaceutical composition include lactose, dextrose, sucrose, sorbitol, mannitol, xylitol, erythritol, maltitol, starch, acacia rubber, alginate, gelatin, calcium phosphate, calcium silicate, cellulose , Methyl cellulose, microcrystalline cellulose, polyvinyl pyrrolidone, water, methylhydroxybenzoate, propylhydroxybenzoate, talc, magnesium stearate and mineral oil. In the case of formulation, a diluent or excipient such as a filler, an extender, a binder, a wetting agent, a disintegrant, or a surfactant is usually used.

The preferred dosage of the pharmaceutical composition of the present invention varies depending on the condition and the weight of the patient, the degree of disease, the drug form, the administration route and the period, but can be appropriately selected by those skilled in the art. However, for the desired effect, the pharmaceutical composition of the present invention is preferably administered at 0.0001 to 100 mg / kg, preferably at 0.001 to 100 mg / kg. The administration may be carried out once a day or divided into several times. The pharmaceutical composition of the present invention can be administered to a mammal including a human by various routes. All modes of administration can be administered, for example, by oral, rectal or intravenous, intramuscular, subcutaneous, intrauterine dural or intracerebroventricular injection.

A composition containing at least one polyphenol compound selected from apigenin, apigeninidine, luteolin, and luteolinidine having antibacterial or antiviral activity isolated from the sorghum extract as an active ingredient may be used as a food additive. have. Foods to which the composition of the present invention is applied as an additive include drink, meat, sausage, bread, chocolate, candy, snacks, confectionary, pizza, ramen, gum, ice cream, soup, beverage, alcoholic beverage and vitamin complex, etc. This is not restrictive. At this time, the amount of the phenolic compound in the food or beverage may be added to 0.01 to 15% by weight of the total food weight, the health beverage composition may be added in a ratio of 0.02 to 5g, preferably 0.3 to 1g based on 100ml It may be appropriate to adjust according to the type of food and the method of use.

A composition containing at least one polyphenol compound selected from apigenin, apigeninidine, luteolin, and luteolinidine having antibacterial or antiviral activity isolated from the sorghum extract as an active ingredient may be used as a feed additive. have. Feeds to which the composition of the present invention is applied as an additive include grains such as wheat, oats, barley, corn, rice, protein feeds such as rape, soybeans, sunflowers, and animal protein feeds such as blood meal, meat meal, bone meal, and fish meal. Feeds can be mixed with amino acids, inorganic salts, vitamins, antibiotics, antimicrobials, antioxidants, fungi, enzymes, and live microbial agents. The feed to which the composition of the present invention is added can be applied to a number of animal diets including mammals, poultry and fish. Mammals can be used on pigs, cattle, sheep, goats, laboratory rodents, fur-owned animals, and livestock. Commercially raised fish, such as trout, may also be included. The feed compounding method of the polyphenol compound is incorporated in an amount of about 0.001 g to 100 g per kg of animal feed. Usually, it is preferable to administer at 0.0001 to 100 mg / kg, preferably at 0.001 to 100 mg / kg.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described concretely with reference to the accompanying drawings, but the present invention is not limited to the embodiments.

Example 1 Analysis of Neuraminidase Enzyme Inhibitory Activity of Natural Sorghum Extract

The following experiment was performed to investigate the inhibitory activity of the antibacterial or antiviral related neuraminidase enzymes of the sorghum natural pigment extracts by varieties and solvents of the golden wax sorghum, milo sorghum and white wax sorghum.

Bacterial-derived neuraminidase was purchased from Sigma-Aldrich and used as substrate 2 ′-(4-methylumberlyryl) -α-DN-acetylneuraminic acid (2 ′-(4-methylumbellifery) -α-DN -acetylneuraminic acid) was purchased from Sigma. The sorghum seeds were dried and ground to 100 mesh, and the sorghum powder obtained through this was shaken and extracted with 100% methanol and 70% ethanol at 30 ° C. for 1 day, filtered through a filter paper, and concentrated under reduced pressure to obtain an extract. The solution was dissolved in methanol, which was dissolved in methanol, and placed in a cuvette. Then, 2mM substrate dissolved in 50mM acetate buffer (pH 5.0) was added, incubated at 37 ° C for 10 minutes, and then bacteria-derived neuraminidase was added. SpectraMax M2e (Molecular Divices, USA) was used to analyze the excitation wavelength 365nm and the emission wavelength 445nm. The inhibition rate was calculated from the difference in fluorescence intensity from the reaction solution in which methanol was added instead of the extract, and 50% of the inhibitory concentration (IC ₅₀ ) values for neuraminidase are shown in Table 1. On the other hand, Equation 1 applied to the activity evaluation of the enzyme is as follows.

   [Equation 1]

Neuraminidase inhibition rate (%) = (A-B) / A × 100

A: Fluorescence intensity value of no inhibitor added

B: Fluorescence value of the added inhibitor

Therefore, the methanol extract of the golden wax sorghum and the myelo sorghum showed a high inhibitory effect of neuraminidase enzyme activity.

Example 2: Separation of Active Ingredient from Sorghum Natural Pigment Extract

The sorghum seeds harvested in 2010 were dried and pulverized to 100 mesh using a pulverizer. 1 kg of sorghum powder obtained through this was placed in an extraction container and extracted with shaking (3 L) containing 0.5% hydrochloric acid at room temperature for 24 hours. The extracted sample was filtered through filter paper, and then concentrated under reduced pressure to obtain a dark red extract (251 g).

1 L of purified water was added and suspended, followed by n-hexane, ethyl acetate, and butanol fractions to obtain n-hexane fraction (25 g), ethyl acetate fraction (48 g), butanol fraction (69 g), and water fraction (37 g), respectively. . Silica gel column chromatography (600 g, 70-230 mesh, Merk) was used from the butanol fraction, and chloroform: methanol (45: 1 to 1:10 mixed ratio) mixed solvent and methanol were sequentially used as mobile phase solvents. Fractions (Fr. B1 to Fr. B5) were obtained. The Fr.B3 fraction (3.9 g) was adsorbed onto silica gel (10 g, 70 to 230 mesh), followed by silica gel column chromatography (100 g, 230 to 400 mesh), wherein the mobile phase solvent was a chloroform: methanol mixed solvent. To obtain an off-white precipitate, which was purified to give Compound 1 (21 mg) and Compound 3 (10 mg). In addition, the Fr. B4 fraction (2.4 g) was adsorbed onto silica gel (8 g, 70 to 230 mesh), and silica gel column chromatography (80 g, 230 to 400 mesh) was performed, wherein the mobile phase solvent was chloroforum: methanol ( 40: 1 to 1:10 mixing ratio) A pale yellow precipitate was obtained using a mixed solvent, which was purified to give compounds 2 (47 mg) and 4 (19 mg). The obtained compound was subjected to nuclear magnetic resonance analysis (Bruker AMX 500), ¹ H NMR, ¹³ C-NMR, HomoCozy (HOMO-COSY), HMQC ( ¹ H-Detected heteronuclear Multiple-Quantum Coherence), HMBC (Heteronuclear Multiple- Bond Coherence) and DEPT (Distortionless Enhancement by Polarization) spectra were analyzed to identify the structure.

The measurement results are as follows. Compound 1 is 4 ′, 5,7-trihydroxyflavone (4 ′, 5,7-trihydroxyflavone; apigenin), compound 2 is 4 ′, 5,7-trihydroxyflavobi Ium (4 ′, 5,7-Trihydroxyflavylium; apigeninidine), compound 3 is 3 ′, 4 ′, 5,7-tetrahydroxyflavone (luteolin), compound 4 is 3 ′, 4 ′, 5 The chemical structure of these compounds is shown in FIG. 1, and the structural characteristics of the isolated polyphenol-based compounds are 3,4 ', 5,7-Tetrahydroxyflavylium (luteolinidine). Is as follows.

[Compound 1] 4 ′, 5,7-tetrahydroxyflavone (apigenin)

1) Properties: Light yellow amorphous crystals

2) Molecular weight: 270.24

3) Molecular formula: C ₁₅ H ₁₀ O ₅

^{4) 1 H-NMR (500MHz} , Methanol- d 4) δ 7.87 (2H, d, J = 14.9 Hz), 6.94 (2H, d, J = 14.9 Hz), 6.62 (1H, s), 6.47 (1H, d, J = 3.5 Hz), 6.23 (1H, d, J = 3.5 Hz)

5) ¹³ C-NMR (125 MHz, methanol- d ₄ )? 184.2, 166.8, 166.6, 163.6, 159.9, 151.4, 147.5, 124.1, 120.7, 117.2, 114.6, 105.5, 104.3, 100.6, 95.4,

[Compound 2] 4 ′, 5,7-Trihydroxyflavinium (Apigeninidine)

1) Properties: Light yellow amorphous crystals

2) Molecular weight: 255.24

3) Molecular formula: C ₁₅ H ₁₁ O ₄

^{4) 1 H-NMR (500MHz} , Methanol- d 4) δ 9.09 (1H, d, J = 14.5 Hz), 8.30 (2H, d, J = 14.9 Hz), 8.05 (1H, d, J = 14.5 Hz) , 7.08 (1H, d, J = 14.9 Hz), 6.95 (1H, d, J = 1.2 Hz), 6.66 (1H, d, J = 1.2 Hz)

^{5) 13 C-NMR (125MHz} , Methanol- d 4) δ 173.2, 172.8, 167.7, 160.9, 160.4, 149.9, 133.6, 133.6, 121.7, 118.8, 118.8, 114.2, 100.8, 103.6, 96.5

[Compound 3] 3 ′, 4 ′, 5,7-tetrahydroxyflavone (luteolin)

 1) Properties: Yellow amorphous crystals

 2) Molecular Weight: 286.24

3) Molecular formula: C ₁₅ H ₁₀ O ₆

4) ¹ H-NMR (500 MHz, DMSO- d ₆ ) δ 7.42 (1H, dd, J = 8.1, 2.3 Hz), 7.40 (1H, d, J = 2.3 Hz,), 6.90 (1H, d, J = 8.1 Hz,), 6.66 (1H, s), 6.45 (1H, d, J = 2.1 Hz,), 6.20 (1H, d, J = 2.1 Hz,).

5) ¹³ C-NMR (125 MHz, DMSO- d ₆ ) δ 182.0, 164.5, 164.3, 161.9, 157.7, 150.1, 146.1, 121.9, 119.3, 116.4, 113.8, 104.1, 103.2, 99.2, 94.2.

[Compound 4] 3 ′, 4 ′, 5,7-tetrahydroxyflavinium (luteolinidine)

1) Properties: Yellow amorphous crystals

2) Molecular weight: 271.24

3) Molecular formula: C ₁₅ H ₁₁ O ₅

^{4) 1 H-NMR (500MHz} , Methanol- d 4) δ 9.05 (1H, d, J = 14.3 Hz), 8.00 (1H, d, J = 14.6 Hz), 7.89 (1H, d, J = 14.0 Hz) , 7.75 (1H, s), 7.04 (1H, d, J = 14.1 Hz), 6.92

^{5) 13 C-NMR (125MHz} , Methanol- d 4) δ 173.2, 172.5, 160.9, 160.4, 156.8, 149.5, 148.7, 125.7, 122.2, 118.2, 116.4, 114.0, 111.1, 103.6, 96.4

¹ H-NMR and ¹³ C-NMR spectra of apigenin and three other polyphenol compounds isolated from sorghum are shown in FIGS. 2A, 2B, 2C and 2D, respectively.

Example 3 Analysis of Neuraminidase Enzyme Inhibitory Activity of Compounds Isolated from Sorghum Natural Pigment Extract

Polyphenol compounds apigenin, apigeninidine, luteolin and luteolinidine components isolated from the sorghum natural pigment extracts were isolated to examine their inhibitory activity against antibacterial or antiviral related neuraminidase enzymes. The phenolic compound was dissolved in methanol as a solvent for each concentration, and the same experiment as in Example 2 was performed to show 50% activity inhibitory concentration (IC ₅₀ ) values for neuraminidase in Table 2 and FIG. 3.

The inhibitory effect of the neuraminidase enzyme activity of the compound isolated from the sorghum was found in the order of luteolin (1.5 times compared to the control), apigeninidine, luteolinidine, and apigenin.

Example 4: Analysis of active ingredient extraction conditions

In this Example, an experiment was conducted to establish the conditions under which the active ingredient exhibiting the effect of inhibiting neuraminidase enzyme was maximized. Active ingredient analysis was performed using an inverse column in the UPLC system (Waters). Figure 4 is a graph analyzing the extraction amount of the active ingredient at different concentrations of methanol and ethanol in the range of 0 to 100%. In addition, Figure 5 shows the extraction amount of the active ingredient obtained when the acid is added to methanol or methanol at different concentrations, Figure 6 shows the maximum amount of the active ingredient extracted in the range of 12 to 72 hours. 7 is a graph showing the extraction amount of the active ingredient under a temperature range of 5 to 40 ° C. As a result, using methanol containing 0.5% hydrochloric acid as the extraction solvent, the maximum active ingredient could be extracted from the sorghum during stirring extraction at 30 ℃ for 24 hours.

Claims (6)

Pharmaceutical composition useful as an antibacterial or antiviral agent comprising sorghum natural pigment extract as an active ingredient and having a neuraminidase inhibitory activity. Apigenin represented by the following Chemical Formula 1, apigeninidine represented by the following Chemical Formula 2, luteolin represented by the following Chemical Formula 3, and luteolinidine represented by the following Chemical Formula 4, isolated from the sorghum natural pigment extract Pharmaceutical composition useful as an antibacterial agent or an antiviral agent containing the above polyphenol compound as an active ingredient.
[Formula 1]

(2)

(3)

[Chemical Formula 4]

3. The method according to claim 1 or 2,
Pharmaceutical composition useful as a prophylactic and therapeutic agent for influenza virus. At least one polyphenol compound selected from apigenin represented by the following formula (1), apigeninidine represented by the following formula (2), luteolin represented by the following formula (3), and luteolinidine represented by the following formula (4) is effective A food additive having antibacterial or antiviral activity as an ingredient. At least one polyphenol compound selected from apigenin represented by the following formula (1), apigeninidine represented by the following formula (2), luteolin represented by the following formula (3), and luteolinidine represented by the following formula (4) is effective A feed additive having antibacterial or antiviral activity as a component. A method for producing a natural sorghum extract, characterized in that the sorghum powder is extracted with a methanol solvent containing 0.1 to 1% hydrochloric acid at a temperature of 5 to 40 ° C.

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