JP7836557B2 - Antibacterial/allergen-reducing composition, method for inhibiting bacterial growth, and method for reducing allergens. - Google Patents

Description

This invention relates to an antibacterial/allergen-reducing composition that can utilize visible light and has high affinity for organic materials, as well as a method for inhibiting bacterial growth and reducing allergens using the antibacterial/allergen-reducing composition.

In recent years, titanium dioxide has attracted attention as an antibacterial substance and is actually being commercialized. Titanium dioxide itself is harmless and is used as a white pigment and food additive, but it is a semiconductor, and when irradiated with ultraviolet light, electrons in the valence band are excited to the conduction band, and holes are generated in the valence band. These electrons reduce oxygen to produce ^superoxide ( _O²⁻ ), and the holes oxidize water molecules to produce hydroxyl radicals (•OH). These reactive oxygen species are thought to decompose bacteria and harmful substances (Non-Patent Literature 1).

However, ultraviolet (UV) light is said to make up only about 5% of sunlight, meaning that in places where sunlight doesn't reach sufficiently, such as indoors, there is almost no UV light. Furthermore, light emitted from fluorescent lamps and LEDs also contains almost no UV light. Therefore, to exert the antibacterial effect of titanium dioxide, it is necessary to deliberately expose it to UV light. Additionally, titanium dioxide, being an inorganic compound, has low affinity for organic materials such as polymers and poor dispersibility. Moreover, because it is opaque, often used as a white pigment, it presents aesthetic problems when applied to clothing.

Therefore, antibacterial organic semiconductors are being investigated. For example, Patent Document 1 discloses a composition for suppressing microbial growth under light irradiation, comprising a photosensitizing compound having an electron-withdrawing group and/or an electron-donating group. Anthracene having an electron-withdrawing group at the 2-position is given as an example of the photosensitizing compound.

Japanese Patent Publication No. 2009-114115

Watanabe, Toshiya et al., Inorganic Materials, Vol. 6, Nov., pp. 532-540 (1999)

As mentioned above, antibacterial organic semiconductors are being investigated. However, among the compounds exemplified in Patent Document 1 as photosensitizing compounds, anthracene readily dimerizes via a [4+4] cyclization reaction, which presents stability problems. Furthermore, the examples described in Patent Document 1 use light including ultraviolet light.
Therefore, the present invention aims to provide an antibacterial/allergen-reducing composition that can utilize visible light and has high affinity for organic materials, as well as a method for inhibiting bacterial growth and reducing allergens using the antibacterial/allergen-reducing composition.

The inventors of this invention conducted extensive research to solve the above problems. As a result, they discovered that certain condensed polycyclic aromatic hydrocarbon compounds having electron-withdrawing groups are useful as active ingredients in antibacterial compositions and allergen-reducing compositions, thus completing the present invention.
The present invention is described below.

[1] An antibacterial/allergen-reducing composition characterized by containing one or more compounds represented by the following formulas (I) to (III) as active ingredients.
[In the formula,
^R1 and ^R2 independently represent H or an electron-withdrawing group, provided that at least one of ^R1 and ^R2 represents an electron-withdrawing group.
^R3 to ^R5 independently exhibit electron-withdrawing groups.
l represents an integer between 0 and 8,
m represents an integer between 1 and 10,
n represents an integer between 1 and 14,
If l is an integer greater than or equal to 2, then multiple ^R3s may be the same or different from one another.
If m is an integer greater than or equal to 2, then multiple ^R4s may be the same or different from one another.
If n is an integer greater than or equal to 2, multiple ^R5s may be identical or different from one another.

[2] The antibacterial/allergen-reducing composition according to [1] above, comprising one or more compounds represented by formula (II) and formula (III) above.

[3] The antibacterial/allergen-reducing composition according to [1] or [2] above, wherein the electron-withdrawing group is one or _more electron-withdrawing groups selected from the group consisting of cyano group, nitro group, carboxyl group, _C1-6 alkylcarbonyl group, _C1-6 alkoxycarbonyl group, formyl group, sulfonic acid group, _C1-6 alkylsulfonyl group, C1-6 alkoxysulfonyl group, tri( _C1-6 alkyl)ammonium group, trihalogenomethyl group, and halogeno group.

[4] An antibacterial/allergen-reducing polymer material characterized by containing an antibacterial/allergen-reducing composition and a polymer as described in any of [1] to [3] above.

[5] An antibacterial/allergen-reducing fiber characterized by containing the polymer material described in [4] above.

[6] An antibacterial/allergen-reducing paint characterized by containing the antibacterial/allergen-reducing composition described in any of [1] to [3] above.

[7] An antibacterial/allergen-reducing spray characterized by containing the antibacterial/allergen-reducing composition described in any of [1] to [3] above.

[8] A method for inhibiting bacterial growth or reducing allergens,
A method characterized by comprising the step of irradiating visible light while the above-mentioned bacteria or allergen and one or more compounds represented by the above-mentioned formulas (I) to (III) are in contact or in close proximity.

The specific condensed polycyclic aromatic hydrocarbon compound used as the active ingredient in this invention can be excited even by visible light, which has lower energy than ultraviolet light, and exhibit antibacterial and allergen-reducing effects. Furthermore, because it is an organic compound, it has high affinity with other organic compounds such as polymers, and can form stable mixtures with polymers. Moreover, it can be made transparent by micronization, making it usable for coating various materials. Therefore, this invention is industrially superior as a potential replacement for conventional antibacterial and allergen-reducing agents.

Figure 1 is a graph showing the change over time in the antibacterial effect against E. coli when irradiated with fluorescent light in or out of the presence of the compound of the present invention. Figure 2 is a graph showing the change over time in the antibacterial effect against E. coli when irradiated with xenon lamp light in or out of the presence of the compound of the present invention.

The antibacterial/allergen-reducing composition according to the present invention contains one or more compounds represented by the above formulas (I) to (III) as active ingredients. An antibacterial/allergen-reducing composition refers to a composition exhibiting antibacterial activity and/or allergen-reducing activity. Hereinafter, the compounds represented by the above formulas (I) to (III) are collectively referred to as "the compounds of the present invention (I) to (III)," and may be referred to as "anthracene compound (I)," "pyrene compound (II)," and "picene compound (III)," respectively.

Compounds (I) to (III) of the present invention have electron-withdrawing groups as substituents. An electron-withdrawing group is a substituent that attracts electrons more readily from the atom to which it is bonded compared to a hydrogen atom. Examples of electron-withdrawing groups include cyano groups (-CN), nitro groups ( _-NO₂ ), carboxyl groups ( _-CO₂H or _-CO₂- ), C₁ ^- ₆ alkylcarbonyl groups [-C(=O)R], C₁ _-6 alkoxycarbonyl groups [-C(=O)OR], formyl groups (-CHO), sulfonic acid groups [-S(=O) _₂OH or -S(=O) _₂O- ], C₁ _-6 ^{alkylsulfonyl} groups [-S(=O) _₂R ], C₁ _-6 alkoxysulfonyl groups [-S(=O) _₂OR ], tri(C₁ _-6 alkyl)ammonium groups (-N ⁺ _R₃ ), trihalogenomethyl groups ( _-CX₃ ), dihalogenomethyl groups ( _-CHX₂ ), halogenomethyl groups ( _-CH₂X ), and halogeno groups (-X). In the formula, R represents a _C1-6 alkyl group, and X represents a halogeno group. If there are multiple _C1-6 alkyl groups or halogeno groups in each group, the multiple _C1-6 alkyl groups or halogeno groups may be the same or different from each other.

" _C1-6 alkyl group" refers to a linear or branched monovalent saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms. Examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, and n-hexyl. Preferably, it is a _C1-4 alkyl group, more preferably a _C1-2 alkyl group, and even more preferably methyl.

A " _C1-6 alkoxy group" refers to a linear or branched saturated aliphatic hydrocarbon oxy group having 1 to 6 carbon atoms. Examples include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, t-butoxy, n-pentoxy, n-hexoxy, etc. Preferably, it is a _C1-4 alkoxy group, more preferably a _C1-2 alkoxy group, and even more preferably methoxy.

Examples of "halogeno groups" include fluoro, chloro, bromo, and iodine. Fluoro is preferred as the halogeno group as a substituent in an electron-withdrawing group, such as a trihalogenomethyl group. Furthermore, chloro, bromo, or iodine are preferred as the halogeno group itself that is the electron-withdrawing group bonded to the condensed polycyclic aromatic hydrocarbon compound, with chloro or bromo being more preferred.

Preferred electron-withdrawing groups include cyano groups, nitro groups, carboxyl groups, _C1-6 alkylcarbonyl groups, _C1-6 alkoxycarbonyl groups, formyl groups, sulfonic acid groups, _C1-6 alkylsulfonyl groups, _C1-6 alkoxysulfonyl groups, tri( _C1-6 alkyl)ammonium groups, trihalogenomethyl groups, and halogeno groups. More preferably, cyano groups, nitro groups, carboxyl groups, formyl groups, and halogeno groups are easier to introduce into condensed polycyclic aromatic hydrocarbon compounds. Among these, cyano groups, nitro groups, carboxyl groups, and formyl groups are even more preferred due to their stronger electron-withdrawing properties.

In condensed polycyclic aromatic hydrocarbon compounds, when the number of electron-withdrawing groups substituted is two or more, the electron-withdrawing groups may be identical or different from each other, but it is preferable that they be identical.

Compounds (I) to (III) of the present invention each have at least one electron-withdrawing group as a substituent. Anthracene compound (I) essentially has an electron-withdrawing group at the 9th and/or 10th positions, but may also have electron-withdrawing groups at other positions. The number of electron-withdrawing groups at positions other than 9th and 10th is preferably 6 or less, more preferably 4 or less, even more preferably 2 or less, and may be 0. Possible substitution positions for electron-withdrawing groups other than 9th and/or 10th positions include positions 1 to 3, with position 1 or 2 being preferred.

The number of electron-withdrawing groups m in pyrene compound (II) is preferably 2 or more, preferably 3 or more, preferably 8 or less, preferably 6 or less, and more preferably 5 or less. The preferred substitution positions for the electron-withdrawing groups in pyrene compound (II) are positions 1, 3, 6, and 8.

The number of electron-withdrawing groups n in picene compound (III) is preferably 12 or less or 10 or less, more preferably 8 or less or 6 or less, and even more preferably 4 or less or 3 or less. The substitution positions of the electron-withdrawing groups in picene compound (III) are preferably at positions 2, 4, 5, 8, 9, and 11, and more preferably at positions 5 and 8.

Anthracenes readily dimerize via a [4+4] cyclization reaction, posing a stability problem. In contrast, the anthracene compound (I) according to the present invention has substituents at positions 9 and 10 of the central ring involved in the cyclization reaction, thus suppressing this dimerization reaction. However, although the reason is unclear, experimental findings by the inventors suggest that even anthracene compound (I) with an electron-withdrawing group at position 9 may experience a decrease in activity over time. Pyrene compound (II) and picene compound (III) are more stable and do not undergo such dimerization reactions; therefore, pyrene compound (II) and/or picene compound (III) are more preferred as active ingredients in the present invention.

The compounds (I) to (III) of the present invention can be synthesized by methods known to those skilled in the art. First, anthracene, pyrene, and picene are commercially available, and those skilled in the art can directly introduce electron-withdrawing groups into these condensed polycyclic aromatic hydrocarbon compounds, or convert the introduced substituents into electron-withdrawing groups.

For example, nitro groups can be directly introduced into condensed polycyclic aromatic hydrocarbon compounds using a mixture of concentrated nitric acid and sulfuric acid, sulfonic acid groups can be introduced using concentrated sulfuric acid or fuming sulfuric acid, and halogen groups can be introduced using metallic iron catalysts or iron halide catalysts and elemental halogens. Halogen groups can be converted into various electron-withdrawing groups such as cyano groups. Furthermore, _C1-6 alkylcarbonyl groups and formyl groups can be introduced via the Friedel-Crafts reaction, and the formyl group can be oxidized to convert it into a carboxyl group. In cases where the position and number of substituents cannot be controlled, the compound with the desired number of substituents introduced in the desired positions can be isolated and purified from the mixture.

The compositions according to the present invention exhibit antibacterial and allergen-reducing effects. It is likely that compounds (I) to (III) of the present invention are excited by visible light, generating reactive oxygen species from oxygen and water molecules. These reactive oxygen species then destroy nearby bacteria and allergens. Antibacterial action refers to at least inhibiting bacterial growth and, in some cases, reducing the number of viable bacteria. Allergen-reducing action refers to reducing the amount of allergens. An antibacterial/allergen-reducing composition refers to a composition exhibiting antibacterial and allergen-reducing effects as described above.

In this invention, "fungi" includes not only fungi and bacteria, but also viruses, although depending on the definition, they may not be included in the category of living organisms. In this invention, "allergen" refers to substances that cause allergies, such as pollen, dust mite feces and carcasses, pet hair, dander, and dust, especially those that are easily dispersed into the air.

The compositions according to the present invention may be incorporated into polymers and used as polymer materials. The active ingredients of the present invention, compounds (I) to (III), are condensed polycyclic aromatic hydrocarbon compounds and therefore have relatively high affinity with polymer materials, and may even exhibit compatibility in some cases. Furthermore, compounds (I) to (III) may be bonded to the polymer. Such bonding may be electrostatic bonding or covalent bonding.

The polymers used in polymer materials should be selected appropriately depending on the application, but examples include polyamide resins such as nylon, polyester resins such as polyethylene terephthalate, acrylic resins such as polyacrylonitrile, polyvinyl resins such as polyvinyl alcohol, polyurethane resins, polyolefin resins such as polyethylene and polypropylene, and fluororesins such as polytetrafluoroethylene.

Polymer materials can be prepared by melt-mixing or reacting compounds (I) to (III) of the present invention with polymers. Furthermore, polymer materials can be molded into various forms, for example, they can be used as fiber materials.

The proportion of compounds (I) to (III) of the present invention in the polymer material can be appropriately adjusted within a range in which the antibacterial and/or allergen-reducing effects are effectively exhibited. For example, it can be between 0.1% by mass and 5% by mass.

The antibacterial/allergen-reducing composition according to the present invention may take the form of a film that coats the surface of a component or other object that needs to be antibacterial or allergen-reduced. Such a film may contain polymers in addition to compounds (I) to (III) of the present invention, or, since compounds (I) to (III) are solid at room temperature, it may not contain polymers.

The film thickness is not particularly limited and can be adjusted as appropriate depending on the film density, etc. For example, it can be 10 μm or more and 500 μm or less. If the thickness is 10 μm or more, the antibacterial and allergen-reducing effects can be more reliably exerted, and if the thickness is 500 μm or less, the compounds (I) to (III) of the present invention in the deeper layers can also be considered to exert their antibacterial and allergen-reducing effects effectively. Preferably, the thickness is 20 μm or more or 50 μm or more, preferably 100 μm or more or 150 μm or more, more preferably 200 μm or more, and more preferably 400 μm or less, and more preferably 300 μm or less.

To form the polymer materials and films described above, paints containing compounds (I) to (III) of the present invention may be used. Furthermore, sprays containing compounds (I) to (III) of the present invention may be used for on-demand sterilization or allergen reduction. While sprays are generally not recognized as being for film formation, in practice, a thin film is formed by the evaporation of the solvent from the spray nozzle, making them substantially indistinguishable from paints in some cases.

The solvent constituting the paint or spray is not particularly limited as long as it can adequately disperse or dissolve compounds (I) to (III) of the present invention. Examples include alcohol-based solvents such as methanol, ethanol, and 2-propanol; ether-based solvents such as diethyl ether and tetrahydrofuran; ketone-based solvents such as acetone, methyl ethyl ketone, and cyclohexanone; water; and mixtures thereof.

The concentration of compounds (I) to (III) of the present invention in paints and sprays can be adjusted as appropriate, but for example, it can be between 0.1% by mass and 10% by mass. If the concentration is 0.1% by mass or higher, the antibacterial and allergen-reducing effects of compounds (I) to (III) can be more reliably exhibited, and if it is 10% by mass or lower, compounds (I) to (III) can be sufficiently dispersed or dissolved in the solvent.

Furthermore, the antibacterial/allergen-reducing composition may contain, as needed, any additives such as surfactants, other antibacterial agents, defoamers, antistatic agents, pH adjusters, thickeners, fragrances, and their respective content.

The method for inhibiting bacterial growth or reducing allergens according to the present invention includes the step of irradiating visible light onto bacteria or allergens while they are in contact with or in close proximity to one or more compounds represented by the above formulas (I) to (III).

"A state in which bacteria or allergens are in contact with or in close proximity to one or more compounds represented by the above formulas (I) to (III)" refers not only to a state in which bacteria or allergens are actually in contact with or in close proximity to the compounds (I) to (III) of the present invention, but also to a state in which they are not actually in contact with or in close proximity but there is a possibility of contact or proximity. In other words, it is not necessary for bacteria or allergens to be in constant contact with or in close proximity to the compounds (I) to (III). For example, it is sufficient for compounds (I) to (III) of the present invention to be present in a state in which bacteria may come into contact with or come into close proximity to the compounds (I) to (III) due to proliferation or diffusion, or in which allergens may come into contact with or come into close proximity to the compounds (I) to (III) due to dispersion. For example, clothing and masks can be made using fibers containing compounds (I) to (III) of the present invention; a spray containing compounds (I) to (III) can be applied to clothing, masks, tables, kitchens, bathrooms, doorknobs, and other surfaces where bacteria and allergens may come into contact or be in close proximity; or a coating can be applied with compounds (I) to (III); or a composition containing compounds (I) to (III) can be placed in places where bacterial growth is to be suppressed, such as aquariums.

The term "proximity" above is not particularly limited as long as compounds (I) to (III) of the present invention can effectively inactivate bacteria or allergens. For example, a distance of 1 μm or less is preferred, and 500 nm or less, or more preferably 200 nm or less. The lower limit of this distance is not particularly limited, but 0 nm, i.e., contact between bacteria or allergens and compounds (I) to (III) of the present invention, is preferred.

Compounds (I) to (III) of the present invention are excited by irradiation with visible light and exhibit antibacterial and allergen-reducing effects. Visible light is not particularly limited, but refers to light having a wavelength of 360 nm or more and 830 nm or less. Preferably, the wavelength is 380 nm or more, more preferably 400 nm or more, preferably 800 nm or less, more preferably 780 nm or less, and even more preferably 760 nm or less. Furthermore, light with a peak wavelength within the above range may be used, and light containing other types of light, as long as visible light is included, may also be used.

Conditions such as the intensity of the irradiated light should be set appropriately so that the effects of the compounds (I) to (III) of the present invention on bacteria and allergens are effectively exerted. For example, sunlight contains about 37% visible light, so sunlight may be used for irradiation. Light from fluorescent lamps or LED lights, which mainly contain visible light, may also be used for irradiation. However, the excitation of compounds (I) to (III) of the present invention, i.e., the antibacterial effect and allergen reduction effect, is stronger with higher irradiated light intensity, and it can be said that sterilization and allergen reduction do not take long, so it is preferable to irradiate compounds (I) to (III) of the present invention with relatively strong visible light. The desired light intensity at the shortest distance position from the light source irradiating visible light to compounds (I) to (III) of the present invention is preferably, for example, 0.1 mW/ ^cm² or more and 100 mW/ ^cm² or less. The light intensity is preferably 0.5 mW/ ^cm² or more, more preferably 1 mW/ ^cm² or more or 2 mW/ ^cm² or more, even more preferably 5 mW/ ^cm² or more, and also preferably 50 mW/ ^cm² or less, even more preferably 20 mW/ ^cm² or less or 10 mW/ ^cm² or less. The shortest distance between the light source and the compounds (I) to (III) of the present invention is preferably 1 m or less, more preferably 50 cm or less, and even more preferably 10 cm or less or 5 cm or less. The lower limit of this shortest distance is not particularly limited, but may be 0 cm.

The conditions for irradiating compounds (I) to (III) of the present invention with visible light should be set appropriately so that the effects of compounds (I) to (III) against bacteria and allergens are effectively exerted. For example, the temperature is not particularly limited and can be room temperature, i.e., 1°C or higher and 35°C or lower. Preferably, the temperature is 5°C or higher or 10°C or higher, more preferably 15°C or higher, and preferably 30°C or lower, and even more preferably 25°C or lower. The visible light irradiation time is also not particularly limited and should be sufficient until the antibacterial and allergen-reducing effects are fully exerted. For example, if the effect is exerted with natural light such as sunlight or normal indoor light, the antibacterial and allergen-reducing effects of compounds (I) to (III) of the present invention can be continuously exerted, so the visible light irradiation time is not limited. When irradiating compounds (I) to (III) of the present invention with relatively strong visible light using a special light source, the visible light irradiation time can be adjusted, for example, to approximately 10 minutes or more and 120 hours or less.

The present invention will be described in more detail below with reference to examples. However, the present invention is not limited by the following examples, and it is certainly possible to implement it with appropriate modifications within the scope that is consistent with the spirit of the preceding and following descriptions. All such modifications are included within the technical scope of the present invention.

Example 1: Synthesis of 5,8-dibromopicene
90 mL of carbon tetrachloride was mixed with picene (0.094 g), Fe powder (0.011 g), and iodine (0.012 g). While keeping the resulting mixture below 10°C, a solution of bromine (0.091 g) dissolved in 1.5 mL of carbon tetrachloride was added dropwise. After the dropwise addition, the mixture was stirred at 10°C for 1 hour, then the temperature was raised to room temperature and stirred overnight. The temperature was further raised to 60°C and stirred for 6 hours. Then, while again keeping the reaction mixture below 10°C, a solution of bromine (0.091 g) dissolved in 1.5 mL of carbon tetrachloride was added dropwise. The reaction mixture was stirred at 10°C for 1 hour, then the temperature was raised to room temperature and stirred overnight, then the temperature was further raised to 60°C and stirred for 6 hours. The resulting reddish-brown solution was cooled to room temperature and washed sequentially with saturated sodium thiosulfate aqueous solution, saturated sodium bicarbonate aqueous solution, and water. The obtained organic phase was dried over anhydrous magnesium sulfate and then evaporated to dryness at 50°C using an evaporator to obtain a pale yellow powder. This powder was recrystallized using toluene to obtain the target compound (yield: 48.5%). Hereafter, 5,8-dibromopicene may be referred to as "Br-picene".

Example 2: Synthesis of 5,8-dicyanopicene
5,8-dibromopicene (0.1 g) synthesized in Example 1 and copper cyanide (0.082 g) were mixed in N,N-dimethylformamide (10 mL) and heated under reflux at 120°C for 24 hours under a nitrogen atmosphere. After cooling to room temperature, the mixture was diluted with dichloromethane (50 mL). The resulting solution was washed with 28% aqueous ammonia and water, the organic phase was dried over anhydrous magnesium sulfate, and then evaporated to dryness using an evaporator to obtain a dark yellow powder. The obtained powder was washed with ethanol to obtain the target compound (yield: 15.2%). Hereinafter, 5,8-dicyanopicene may be referred to as "CN-picene".

Example 3: Synthesis of 1,3,6,8-tetracyanopyrene
1,3,6,8-tetrabromopyrene (0.1 g) and copper cyanide (0.082 g) were mixed in N,N-dimethylformamide (10 mL) and heated under reflux at 120°C for 24 hours under a nitrogen atmosphere. After cooling to room temperature, the mixture was diluted with dichloromethane (50 mL). The resulting solution was washed with 28% aqueous ammonia and water, the organic phase was dried over anhydrous magnesium sulfate, and then evaporated to dryness using an evaporator to obtain a dark yellow powder. The obtained powder was washed with ethanol to obtain the target compound (yield: 15.2%). Hereafter, 1,3,6,8-tetracyanopyrene may be referred to as "CN-pyrene".

Example 4: Thin Film Preparation A predetermined amount of 5,8-dicyanopicene synthesized in Example 2 was weighed out and deposited onto a transparent quartz glass plate (Asahi Seisakusho Co., Ltd., 40 × 10 × 0.5 mm) using a vacuum deposition apparatus ("SVC-700 TURBO TM", manufactured by Sanyu Electronics Co., Ltd.) under the following deposition conditions.
[Vapor deposition conditions]
Internal pressure: < ^10⁻³ Pa
Vapor deposition rate: 0.1 nm/s
Substrate temperature: 298K
Film thickness: 300 nm
Glass plates were also prepared in the same manner by forming thin films of 5,8-dibromopicene (Br-picene) synthesized in Example 1, commercially available 9-cyanoanthracene (CN-anthracene) and 9-nitroanthracene ( _NO2 -anthracene), and 1,3,6,8-tetracyanopyrene (CN-pyrene) synthesized in Example 3.

Example 5: Antifungal experiment 350 mL of beer was mixed with sugar (3.5 g) and agar powder (5.25 g) and heated at 100°C for 2 hours to remove alcohol and carbon dioxide. The mixture was then dispensed into plastic petri dishes and allowed to cool at room temperature until the culture medium solidified to prepare an agar medium.
0.01 g of dry yeast powder was added to 100 mL of deionized water and stirred. This bacterial solution was diluted 10-fold with deionized water, and 10 μL was spread onto an agar plate using a convection rod. The petri dish was then inverted and incubated at 37°C for 50 hours. After that, the number of colonies _N0 that appeared on the agar plate was counted.
Separately, the above dry yeast solution (4 mL) was placed in a cylindrical quartz reactor, and a glass plate with a photocatalytic thin film prepared in Example 4 was then placed inside. Under normal room light, the reactor was irradiated for 1 hour using a colored glass filter ("UV-42" manufactured by HOYO) to remove light below 420 nm from a 500 W xenon lamp. Next, the bacterial solution was diluted 10-fold with deionized water, 10 μL was spread onto an agar plate, and the petri dish was inverted and incubated at 37°C for 50 hours. After that, the number of colonies N that appeared on the agar plate was counted.
For comparison, the experiment was conducted in the same manner except that visible light was not irradiated from a xenon lamp, or a glass plate with a photocatalytic thin film was not used, or neither a glass plate with a photocatalytic thin film was used nor visible light was irradiated from a xenon lamp, and the number of colonies _N0 was counted.
The antifungal rate was calculated from the obtained measurements according to the following formula. The results are shown in Tables 1 to 3.
Antifungal rate (%) = (1-N/N ₀ ) x 100

As shown in Tables 1-3, the antifungal effect was insufficient when no photocatalyst was used or when visible light was not irradiated. The slightly higher antifungal rate when no photocatalyst was used and visible light was irradiated is thought to be due to the influence of high-energy, short-wavelength light that could not be completely filtered out. Furthermore, the fact that the antifungal rate did not reach 0% even when no photocatalyst was used and visible light was not irradiated is thought to be because, when counting colony count _N , the incubation period is one hour longer under conditions that are not optimal for yeast compared to when counting colony count N0.
On the other hand, when a photocatalyst was used and visible light was irradiated, a significant improvement in the antifungal rate was observed.

Example 6: Antimicrobial Experiment Ion-exchanged water (300 mL), agar powder (4.5 g), and LB medium powder (6 g) were placed in an Erlenmeyer flask and autoclaved at 121°C for 20 minutes. After air cooling for 2 hours, the mixture was dispensed into plastic petri dishes in a clean bench and allowed to cool until solid to form LB solid medium. E. coli was scooped up with a platinum loop and streaked in a zigzag pattern starting from four points on the edge of the petri dish before being inoculated onto the solid medium. It was then cultured overnight at 37°C. A small amount of the obtained E. coli single colonies was scraped off with a platinum loop and inoculated into LB liquid medium. It was cultured overnight at 37°C while shaking from side to side with a shaker. The resulting E. coli solution was diluted 1000 times by volume with physiological saline sterilized by autoclaving.
A 5.9 mL quartz tube reactor was placed in a glass plate with a CN-picene thin film prepared in Example 4 and a 1000-fold diluted E. coli solution (4 mL), and the reactor was irradiated with fluorescent light for 6 hours.
Bacterial suspension samples were collected 1, 2, 3, and 6 hours after the start of light irradiation, diluted 100-fold with physiological saline, and spread 10 μL onto LB agar plates. The samples were incubated overnight at 37°C, and the number of colonies N on the agar plates was counted. As a control, E. coli was cultured in the same manner except that a glass plate with a CN-picene film was not used, and the number of colonies _N0 on the agar plates was counted. The antimicrobial efficacy was calculated according to the following formula. The results are shown in Figure 1.
Antibacterial rate (%) = (1-N/N ₀ ) x 100
Furthermore, the experiment was conducted in the same manner as above, except that a 500W xenon lamp was used instead of a fluorescent lamp, and light below 420 nm was removed from the light of the 500W xenon lamp using a colored glass filter ("UV-42" manufactured by HOYO Corporation) before irradiating the reactor. The results are shown in Figure 2.

As shown in Figure 1, when a glass plate coated with a CN-picene film was not used, the rate of E. coli death under fluorescent light was very slow. In contrast, when a glass plate coated with a CN-picene film was used, the antibacterial rate against E. coli reached 100% within 6 hours from the start of the experiment. These experimental results demonstrate that CN-picene exhibits excellent antibacterial activity even under normal light irradiation from fluorescent lamps.
Furthermore, as shown in Figure 2, when irradiated with xenon lamp light, which is stronger than fluorescent light, the rate of E. coli death increased even further, and the antibacterial rate against E. coli reached 100% three hours after the start of the experiment. It is thought that the antibacterial rate continued to increase over time even without using a glass plate with a CN-picene thin film when irradiated with xenon lamp light, due to the effect of ultraviolet rays that could not be completely filtered out by the xenon lamp light.

Claims (8)

An antimicrobial composition characterized by containing one or more compounds represented by the following formula (I) or formula (III) as an active ingredient.

[In the formula,
^R1 and ^R2 independently represent H or an electron-withdrawing group, provided that at least one of ^R1 and ^R2 represents an electron-withdrawing group.
^R3 and ^R5 independently exhibit electron-withdrawing properties.
The above electron-withdrawing group is one or more electron-withdrawing groups selected from the group consisting of cyano groups, nitro groups, carboxyl groups, and halogeno groups.
l represents an integer between 0 and 8 ,
n represents an integer between 1 and 14,
If l is an integer greater than or equal to 2, then multiple ^R3s may be the same or different from one another .
If n is an integer greater than or equal to 2, multiple ^R5s may be identical or different from one another. The antibacterial composition according to claim 1, comprising one or more compounds represented by the above formula (III). The antibacterial composition according to claim 1 or 2, wherein the number of substituents on the electron-withdrawing group in the above compound is two or more . An antimicrobial polymer material characterized by containing the antimicrobial composition and polymer described in any one of claims 1 to 3. An antibacterial fiber characterized by containing the polymer material described in claim 4. An antibacterial paint characterized by containing the antibacterial composition described in any one of claims 1 to 3. An antibacterial spray agent characterized by containing the antibacterial composition described in any one of claims 1 to 3. A method for suppressing the growth of bacteria,
A method characterized by comprising the step of irradiating visible light with the above-mentioned bacteria and one or more compounds represented by the following formula (I) or formula (III) while they are in contact or in close proximity.

[In the formula,
^R1 and ^R2 independently represent H or an electron-withdrawing group, provided that at least one of ^R1 and ^R2 represents an electron-withdrawing group.
^R3 and ^R5 independently exhibit electron-withdrawing properties.
The above electron-withdrawing group is one or more electron-withdrawing groups selected from the group consisting of cyano groups, nitro groups, carboxyl groups, and halogeno groups.
l represents an integer between 0 and 8 ,
n represents an integer between 1 and 14,
If l is an integer greater than or equal to 2, then multiple ^R3s may be the same or different from one another .
If n is an integer greater than or equal to 2, multiple ^R5s may be identical or different from one another.