Antimicrobial composition

Abstract

To provide an antimicrobial composition hardly causing discoloration and aggregation and containing a metal ion.SOLUTION: An antimicrobial composition comprises a metal ion as an active ingredient for antimicrobial activity, a thiol group-containing compound, and a solvent. This makes it possible for the thiol group-containing compound to prevent discoloration of the object to which the antibacterial composition is applied, and aggregation of the active ingredient. In addition, by preventing aggregation, the active ingredient is likely to be uniformly dispersed in the solution, and the effect of the antimicrobial action can be efficiently exhibited.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an antibacterial composition. More specifically, the present invention relates to an antibacterial composition containing metal ions as an active ingredient and a thiol group-containing compound therein.

Background Art

[0002] Heavy metal ions such as silver, copper, and zinc are known to have bactericidal properties. That is, after the heavy metal ions are taken up by bacteria, they bind to proteins such as enzymes to cause inhibition of function and exhibit a bactericidal effect. In this case, the heavy metal ions can exhibit a bactericidal effect at a low concentration of about several ppm. Therefore, the bactericidal method using heavy metal ions can be said to be a bactericidal method that combines usefulness and economy.

[0003] Among such heavy metal ions, silver ions have been widely used for antibacterial purposes since ancient times because of their high safety to humans. Therefore, technologies for antibacterial compositions containing silver ions as an active ingredient have been disclosed (Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Disclosure of the Invention

Problems to be Solved by the Invention

[0005] However, when using metal ions as antibacterial agents, it has been known that the reduced metal ions react with the object to cause discoloration, or that the compound containing metal ions causes aggregation and precipitation. These points have been known as problems when using metal ions as active ingredients. Against this background, an object of the present invention is to provide an antibacterial composition containing metal ions that is less likely to cause discoloration and aggregation.

Means for Solving the Problems

[0006] As a result of intensive research, the inventors have found an antibacterial composition that makes it difficult for metal ions to cause discoloration and aggregation by adding a thiol group-containing compound to an antibacterial solution containing metal ions as an active ingredient, and further improves antibacterial properties by using a surfactant, thereby completing the invention.

[0007] The present invention comprises the following constitution. [1] An antibacterial composition characterized by comprising metal ions as an active ingredient for antibacterial, a thiol group-containing compound, and a solvent.

[0008] [2] The antibacterial composition according to [1], wherein the thiol group-containing compound is a thiol group-containing amino acid. [3] The antibacterial composition according to [2], wherein the thiol group-containing amino acid is selected from any one or more of captopril, cysteine, and methionine.

[0009] [4] The antibacterial composition according to [1], wherein the thiol group-containing compound is a thiol group-containing polypeptide. [5] The antibacterial composition according to [4], wherein the thiol group-containing polypeptide comprises at least one cysteine or methionine and 2 to 9 natural amino acids. [6] The antibacterial composition according to [5], wherein the thiol group-containing polypeptide is glutathione.

[0010] [7] The antibacterial composition according to [1], wherein the thiol group-containing compound is dimercaptoalkyl alcohol. [8] The antibacterial composition according to [7], wherein the dimercaptoalkyl alcohol is either dimercaptopropanol or dimercaptoethanol.

[0011] [9] The antibacterial composition according to [1], wherein the metal ion is a silver ion.

[10] The antibacterial composition according to [1], further comprising a surfactant as a composition component.

[11] The antibacterial composition according to

[10] , wherein the surfactant contains any one or more of sodium linear alkylbenzene sulfonate, alkyl glycoside, alkylamine oxide, quaternary ammonium salt, polyoxyethylene alkyl ether, polyethylene glycol alkyl ether, and water-soluble modified silicone oil. [Advantages of the Invention]

[0012] The present invention enables the provision of an antibacterial composition containing metal ions that is less likely to cause discoloration or aggregation. [Brief Description of the Drawings]

[0013]

Figure 1

Figure 2

Figure 3

[0014] The present invention will be described.

[0015] The antibacterial composition of the present invention is characterized by comprising a metal ion which is an active ingredient for antibacterial, a thiol group-containing compound, and a solvent. That is, a thiol group-containing compound can prevent discoloration of an object to which an antibacterial composition is applied, etc., and aggregation of the active ingredient. Further, by preventing aggregation, the active ingredient is likely to be uniformly dispersed in the solution, and it becomes possible to efficiently exhibit the effect of the antibacterial action.

[0016] In the present invention, the thiol group-containing compound is defined as a compound having a thiol group in the molecule. Further, the thiol group-containing compound is preferably water-soluble in consideration of solvent affinity. As such a thiol group-containing compound, a thiol group-containing amino acid or a thiol group-containing peptide can be used.

[0017] The thiol group-containing amino acid is defined as an amino acid having a thiol group. The thiol group-containing amino acid does not particularly need to be limited as long as it is an amino acid having a thiol group, and it may be a natural amino acid or an artificially synthesized amino acid that does not exist in nature. Typically, captopril, cysteine, methionine, etc. can be used as the thiol group-containing amino acid, and preferably captopril can be used.

[0018] The thiol group-containing polypeptide is defined as a polypeptide having a thiol group. The thiol group-containing polypeptide does not particularly need to be limited as long as it is a polypeptide having a thiol group, and various ones can be used. The thiol group-containing polypeptide is preferably water-soluble in consideration of solvent affinity. From this, as a guideline for the amino acid residues of the polypeptide, typically, it can be 2 to 30, preferably 2 to 20, more preferably 2 to 16, still more preferably 2 to 14, particularly preferably 2 to 12, and most preferably 2 to 10.

[0019] The thiol group-containing polypeptide preferably contains at least one cysteine or methionine and is composed of other sequences of natural amino acids. This facilitates the design of the thiol group-containing polypeptide and has the effect of reducing the production cost of the thiol group-containing polypeptide. The thiol group-containing polypeptide may have at least one cysteine or methionine as described above, and may further have an amino acid sequence containing 1 to 30, preferably 1 to 20, more preferably 1 to 16, still more preferably 1 to 14, particularly preferably 1 to 12, and most preferably 1 to 10 natural amino acids. As the natural amino acids, for example, alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine, etc. can be used. As such a thiol group-containing polypeptide, glutathione can preferably be used.

[0020] In the present invention, dimercaptoalkyl alcohol can be used as the thiol group-containing compound. In the present invention, dimercaptoalkyl alcohol is defined as an alkyl alcohol having two thiol groups in the molecule. As such dimercaptoalkyl alcohol, for example, dimercaptopropanol, dimercaptoethanol can be used, and preferably dimercaptopropanol can be used.

[0021] Regarding the thiol group-containing compound, it may be in a sufficient amount to exhibit discoloration resistance and dispersion effect with respect to the amount of metal ions contained in the composition liquid. The content of the thiol group-containing compound can typically be in a weight ratio of 1 to 500 times, preferably 1 to 400 times, more preferably 1 to 400 times, still more preferably 1 to 300 times, particularly preferably 1 to 200 times, and most preferably 1 to 150 times that of the metal ions.

[0022] In the present invention, the metal ion plays a role as an active ingredient that exhibits antibacterial properties. The antibacterial metal does not particularly need to be limited as long as it plays such a role, and it can be selected from various metals. As the metal ion, a metal cation may be used. As such a metal cation, for example, any one or more of gold, silver, copper, platinum, zinc, titanium, tungsten, nickel, iron, tin, mercury, palladium, aluminum, cobalt, molybdenum, lead, vanadium, zirconium may be selected, and preferably, silver can be used.

[0023] In the present invention, the metal ion content may be an amount sufficient to exhibit antibacterial properties. The metal ion content can typically be added at a concentration of 0.1 to 100,000 ppm, preferably 10 to 10,000 ppm, more preferably 10 to 1,000 ppm, particularly preferably 10 to 500 ppm, and most preferably 10 to 300 ppm.

[0024] In the present invention, the solvent plays a role of dissolving the metal ion and the thiol group-containing compound which are the composition components. The solvent does not particularly need to be limited as long as it plays such a role, and various solvents can be used. Since the metal ion and the thiol group-containing compound are basically water-soluble, an aqueous solvent can be used as the solvent. Typically, water may be used as the aqueous solvent, and if necessary, a trace amount of an organic solvent or an additive can be included. When using an organic solvent, an amphiphilic organic solvent miscible with the aqueous solvent may be used. For example, methanol, ethanol, propanol, isopropyl alcohol, tetrahydrofuran, acetone, ethyl methyl ketone, acetonitrile, DMF, HMPA, triethylamine, DMSO, etc. can be used, and preferably, methanol, ethanol, propanol, isopropyl alcohol can be used.

[0025] In the present invention, it is preferable to further use a surfactant as a constituent component. Thereby, the solubility of the thiol group-containing compound is improved, the antibacterial property is improved, and the performance of the antibacterial composition of the present invention is improved. As the surfactant, a surfactant that can be used in an aqueous solvent can be used. Examples of such surfactants include sodium linear alkylbenzene sulfonate, alkyl glycoside, alkylamine oxide, quaternary ammonium salt, polyoxyethylene alkyl ether, polyethylene glycol alkyl ether, and water-soluble modified silicone oil.

[0026] Examples of the polyethylene glycol alkyl ether include polyethylene glycol mono-2-ethylhexyl ether, polyethylene glycol monooctyl ether, polyethylene glycol monodecyl ether, polyethylene glycol monododecyl ether, polyethylene glycol monotetradecyl ether, and the like. As the sodium linear alkylbenzene sulfonate, for example, sodium decylbenzene sulfonate, sodium dodecylbenzene sulfonate, and the like, sodium benzene sulfonate having a linear alkyl chain having 8 to 22 carbon atoms can be used. Examples of the alkyl glycoside include octyl glucoside, decyl glucoside, lauryl glucoside, and the like, and an alkyl glycoside having 8 to 22 carbon atoms, more preferably 8 to 12 carbon atoms can be used. Examples of the alkylamine oxide include amine oxides having an alkyl group having 8 to 22 carbon atoms such as lauryldimethylamine oxide. Examples of the polyoxyethylene alkyl ether include polyoxyethylene behenyl ether, polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether, and the like, and polyoxyethylene alkyl ethers having 8 to 22 carbon atoms can be used. As the polyethylene glycol alkyl ether, for example, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol butyl ether, diethylene glycol methyl ethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, etc. can be used. As the quaternary ammonium salt, for example, benzalkonium chloride, benzethonium chloride, methylbenzethonium chloride, cetylpyridinium chloride, cetrimonium, dofanium chloride, tetraethylammonium bromide, didecyldimethylammonium chloride, domiphen bromide, sodium linear alkylbenzene sulfonate, alkyl glycoside, alkylamine oxide, dialkyldimethylammonium chloride, polyoxyethylene alkyl ether, alkyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, behenyltrimethylammonium chloride, fatty acid ester of tri(oxyethylene)methylammonium salt methyl sulfate, diallyldimethylammonium chloride, dialkyldimethylammonium chloride, ditallow alkyldimethylammonium chloride, hexadecyltrimethylammonium methosulfate salt, didecyldimethylammonium methosulfate, coconut alkyl bis(2-hydroxyethyl)methylammonium chloride, polyoxyethylene coconut alkylmethylammonium chloride, oleyl bis(2-hydroxyethyl)methylammonium chloride, tetramethylammonium chloride, tetrapropylammonium hydroxide, tetrabutylammonium bromide, tetrabutylammonium hydroxide, trimethylphenylammonium chloride, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyltributylammonium chloride, any of the dialkyldimethylammonium chloride salts can be selected. As the water-soluble modified silicone oil (polyether-modified silicone), PEG-3 methyl ether dimethicone, PEG-9 dimethicone, PEG-10 methyl ether dimethicone, PEG-11 methyl ether dimethicone, PEG12 dimethicone, PEG / PPG-20 / 22 butyl ether dimethicone, lauryl PEG / PPG-18 / 18 methicone, poly(oxyethylene·oxypropylene) methyl polysiloxane copolymer, polyoxyethylene·methyl polysiloxane copolymer can be used.

Example

[0027] The present invention will be described in detail using examples.

[0028] <<Experiment 1>> <I. Experimental method> <Color fastness test> 1. For the antibacterial composition liquid, the color fastness test was carried out by the following method. (1) Papers, plastics, paint-coated surfaces, wallpapers, those cut into appropriate sizes were prepared as experimental samples. (2) 20 μL of each test liquid was dropped onto the experimental samples. (3) After leaving it standing in the indoor atmosphere for 1 day or more, the surface of the dropped part was observed, and the evaluation of the presence or absence of discoloration was performed visually.

[0029] <Antibacterial evaluation> For each prepared antibacterial composition liquid, the antibacterial property was evaluated by the following procedure. (1) Each prepared test liquid was sprayed onto an acrylic piece and dried. (2) Candida albicans pre-cultured was dissolved in 10 mL of pure water, and 50 μL of it was dropped onto the acrylic piece, and then an air-permeable film was adhered. (3) 30 minutes after adhesion in (2), the air-permeable film was peeled off, the medium was pressed, and the collected bacteria were cultured in a thermostatic bath for 48 hours. (4) The number of colonies in the cultured medium was counted by the number of colonies in the positive control group (unprocessed acrylic piece). The sterilization rate was determined except for this.

[0030] <II. Experimental Results> 1. The experimental results are shown in Fig. 1. (1) In Experimental Example 1 which does not contain components other than silver ions, although discoloration of the solution itself was not observed, obvious discoloration was confirmed in all samples after coating. (2) In Experimental Example 2 where only glutathione was added, discoloration disappeared in plastics and remained only slightly in wallpapers. From this, it was confirmed that the tendency of discoloration was alleviated by adding only glutathione. (3) In Experimental Example 3 where glutathione, arginine, and a surfactant were added, the tendency of discoloration was alleviated in all samples, but the solution itself was clearly discolored. From this, it was considered that the stability as a composition solution might be impaired. (4) In Experimental Example 4 where glutathione, nucleic acid (sodium guanylate), and a surfactant (PVP) were added, the tendency of discoloration was alleviated in plastics and wallpapers, but as in Experimental Example 3, the solution itself was discolored, and it was considered that the stability as a composition solution might be impaired. (5) In Experimental Example 5 where glutathione and a surfactant were added, the tendency of discoloration was alleviated in all samples, and there was no discoloration of the solution itself. (6) In Experimental Example 6 where captopril and a surfactant were added, the tendency of discoloration was alleviated in all samples, and there was no discoloration of the solution itself. (7) In any of the experimental examples, the antibacterial property was almost 100%, and the antibacterial property as a composition solution was maintained.

[0031] 2. From these results, the following was found. (1) It was found that glutathione tends to alleviate discoloration of the samples. In addition, it was found that the alleviating effect becomes more excellent by using a surfactant. (2) It was found that the discoloration-relieving effect of glutathione is inhibited by arginine or nucleic acid. (3) It was found that captopril has a tendency to relieve the discoloration of the sample.

[0032] <<Experiment 2>> <Experimental method> The test was conducted in accordance with the discoloration resistance test of Experiment 1.

[0033] <Experimental results> 1. The experimental results are shown in Figure 3. (1) In the captopril of Experimental Example 7, discoloration of the solution and discoloration of the application target were not confirmed at any concentration. (2) In the glutathione of Experimental Example 8, discoloration of the solution could not be confirmed in the examination at a concentration of 1000 ppm, but obvious coloring of the application target was confirmed. (3) In the dithioerythritol of Experimental Example 9, discoloration and precipitation of the solution were confirmed at any concentration. Also, slight discoloration was observed in the application target. (4) In the dithiothreitol of Experimental Example 10, discoloration and precipitation of the solution were confirmed at any concentration. Also, slight discoloration was observed in the application target. (5) In the sodium thiosulfate pentahydrate of Experimental Example 11, discoloration and precipitation of the solution were not observed at any concentration. Also, obvious discoloration was observed in the application target at 500 ppm, while only slight discoloration was observed at 1000 ppm. (6) In the ethylene thiourea of Experimental Example 12, discoloration and precipitation of the solution were not observed at any concentration, but obvious discoloration of the application target was confirmed. (7) In the dimercaptopropanol of Experimental Example 13, slight discoloration of the solution was observed at any concentration, but discoloration was not confirmed in the application target. 2. From these results, it was considered that captopril and dimercaptopropanol, which do not affect the application target, exhibited excellent performance.

Claims

1. A metal ion which is an active ingredient for antibacterial action, a thiol group-containing compound, and a solvent, characterized in that it consists of these and is an antibacterial composition.

2. The antibacterial composition according to Claim 1, wherein the thiol group-containing compound is a thiol group-containing amino acid.

3. The antibacterial composition according to Claim 2, wherein the thiol group-containing amino acid is selected from any one or more of captopril, cysteine, and methionine.

4. The antibacterial composition according to Claim 1, wherein the thiol group-containing compound is a thiol group-containing polypeptide.

5. The antibacterial composition according to Claim 4, wherein the thiol group-containing polypeptide consists of at least one cysteine or methionine, and 2 to 9 natural amino acids.

6. The antibacterial composition according to Claim 5, wherein the thiol group-containing polypeptide is glutathione.

7. The antibacterial composition according to Claim 1, wherein the thiol group-containing compound is a dimercaptoalkyl alcohol.

8. The antibacterial composition according to Claim 7, wherein the dimercaptoalkyl alcohol is any one of dimercaptopropanol and dimercaptoethanol.

9. The antibacterial composition according to Claim 1, wherein the metal ion is a silver ion.

10. The antibacterial composition according to Claim 1, further containing a surfactant as a composition component.

11. The antibacterial composition according to Claim 10, wherein the surfactant contains any one or more of sodium linear alkylbenzene sulfonate, alkyl glycoside, alkylamine oxide, quaternary ammonium salt, polyoxyethylene alkyl ether, polyethylene glycol alkyl ether, and water-soluble modified silicone oil.

Images