Oral composition

Abstract

To provide a new technology for enhancing an effect of inhibiting biofilm formation.SOLUTION: An oral composition comprises, as active ingredients, component (a): an extract of algae of the family Codiaceae, and component (b): a zinc compound.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an oral composition. [Background technology]

[0002] Dental plaque is a mixed biofilm formed by various bacteria in the oral cavity. It is known that the adhesion and accumulation of dental plaque on the periodontal and tooth surfaces can cause dental caries and periodontitis. Biofilms are formed when gram-positive bacteria such as Streptococcus adhere to the tooth surface and periodontal surfaces in the initial stage, and then gram-negative colonizing bacteria such as the periodontal pathogen Porphyromonas gingivalis are incorporated into the biofilm, leading to the development of pathogenicity.

[0003] Patent Documents 1 and 2 describe techniques relating to the inhibition of dental plaque or biofilm formation. Patent Document 1 (International Publication No. 2022 / 172807) describes an oral care composition that contains an extract of Myrrhaceae algae and a protein with a molecular weight of 5,000 or more contained in the extract as an active ingredient (Claim 1). It is said that this composition can inhibit the adhesion of bacteria floating in the oral cavity to teeth without using an antibacterial ingredient or by using a low concentration of the antibacterial ingredient (Paragraph 0013).

[0004] Furthermore, Patent Document 2 (JP Patent Publication No. 2023-71595) describes (paragraph 0007) a technology relating to an oral composition that significantly enhances the effect of inhibiting plaque formation, which contains erythritol, a specific amount of an amphoteric surfactant, and a menthol, and the blending ratio of the amphoteric surfactant and the menthol falls within a specific range (Claim 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2022 / 172807 [Patent Document 2] Japanese Patent Publication No. 2023-71595 Summary of the Invention [Problem to be solved by the invention]

[0006] The inventors' investigations have revealed that the effects of the techniques described in Patent Documents 1 and 2 still leave room for improvement in terms of preventing periodontal disease.

[0007] Therefore, the present invention provides a new technique for improving the inhibitory effect on biofilm formation. [Means for solving the problem]

[0008] According to the present invention, the following oral compositions and methods for inhibiting biofilm formation are provided. [1] An oral composition comprising the following ingredients (a) and (b) as active ingredients: (a) Extract of Millidae algae (b) Zinc compounds [2] The oral composition according to [1], wherein component (b) is one or more compounds selected from the group consisting of zinc chloride, zinc gluconate, and zinc stearate. [3] The oral composition according to [1] or [2], wherein the mass ratio ((b) / (a)) of the content of component (b) to the content of component (a) is 0.1 or more and 20 or less. [4] An oral composition according to any one of [1] to [3], wherein the content of component (a) in the oral composition is 0.025% by mass or more and 1% by mass or less relative to the total oral composition. [5] An oral composition described in any one of [1] to [4], which is an inhibitor of biofilm formation. [6] An oral composition according to any one of [1] to [5], which is a mouthwash or a dentifrice. [7] A method for inhibiting biofilm formation, comprising applying the oral composition described in any one of [1] to [6] to the oral cavity.

[0009] The present invention also provides use of a composition containing the components (a) and (b) for the manufacture of an inhibitor of biofilm formation. [Effects of the Invention]

[0010] According to the present invention, a new technique for improving the effect of inhibiting biofilm formation can be provided. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 shows the evaluation results of the inhibitory effect on biofilm formation in an example. [Figure 2] FIG. 1 shows the evaluation results of the inhibitory effect on biofilm formation in an example. [Figure 3] FIG. 1 shows the evaluation results of the inhibitory effect on biofilm formation in an example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described. In this embodiment, the composition may contain each component either alone or in combination of two or more. In this specification, the symbol "to" indicating a numerical range means "greater than or equal to" or "less than or equal to," and both of the numerical values ​​at both ends are included.

[0013] (Oral composition) In this embodiment, the oral composition contains the following components (a) and (b) as active ingredients. (a) Extract of Millidae algae (b) Zinc compounds

[0014] The oral composition of this embodiment contains the above-mentioned components (a) and (b) in combination, and therefore can achieve an excellent biofilm formation inhibitory effect while suppressing the metallic taste of the oral composition, such as a liquid oral composition. Furthermore, according to this embodiment, the combined use of components (a) and (b) also makes it possible to reduce the amount of component (b) applied to the oral cavity compared to when these components are not combined. This improves the balance between the reduction in the metallic taste of oral compositions such as liquid oral compositions and the biofilm formation inhibitory effect due to the synergistic effect of components (a) and (b). Therefore, the oral composition of the present embodiment is also suitable as an inhibitor of biofilm formation, thereby reducing various symptoms caused by biofilm formation. Here, the inhibition of biofilm formation may be either complete inhibition or partial inhibition (reduction) of biofilm formation. Each component will be described below.

[0015] (Component (a)) Component (a) is an extract of algae of the family Myridae. Specifically, component (a) is extracted from algae belonging to the family Codiaceae in the order Bryopsiales (including the former Codiales) of the class Chlorophyceae. Specific examples of algae in component (a) include Codium fragile, Codium tomentosum, Codium minus, Codium spongiosum, Codium subtubulosum, Codium intricatum, Codium adhaerens, Codium arabicum, Codium coactum, Codium barbatum, Codium contractum, Codium latum, and Codium cylindricum. Component (a) is, for example, an extract of the algae bodies of these algae. The algae of the family Myridae is preferably Myrida, which can more stably improve the inhibitory effect on biofilm formation.

[0016] Component (a) may be an extract from any tissue of the algal body of a Millidae algae, or may be an extract from the algal body obtained by culturing a Millidae algae in a medium.

[0017] It is also preferred that component (a) contains a protein fraction. The molecular weight of the protein fraction is preferably 5,000 or more, and also preferably less than 50,000, more preferably less than 30,000. This allows for more stable and improved inhibitory effect against biofilm formation.

[0018] It is also preferable that component (a) contains a lectin that binds to glycans that compete with N-acetyl-D-galactosamine (GalNAc). The lectin is not limited to those that bind to all glycans that have GalNAc at the terminal. For example, it may bind only to glycans with a specific structure in the second or third sugar residue from the terminal, but the binding may be inhibited in the presence of GalNAc. Furthermore, the lectin may bind to GalNAc present on the surface of a membrane formed by polysaccharides contained in biopolymers of saliva, thereby inhibiting the adhesion of oral bacteria to the membrane.

[0019] Here, lectins refer to proteins other than antibodies, T cell receptors, Toll-like receptors, and other immune proteins involved in the animal immune system that have the ability to specifically bind to sugar chains. Lectins are generally capable of agglutinating red blood cells and other animal cells. It has been reported that lectins derived from Myridae algae are commonly GalNac-specific (Kanji Hori, Chemistry and Biology, 1994, Vol. 32, No. 9, pp. 586-594).

[0020] Component (a) may be obtained by any method as long as the effects of the present invention are not substantially impaired. For example, component (a) can be obtained by extraction from any tissue of the algae of the genus Myrtle. More specifically, the algae may be washed, then crushed with a homogenizer or the like, and then subjected to extraction treatment. Alternatively, the algae may be washed, then freeze-dried, ground into powder using a grinder, or the like, and then subjected to extraction treatment.

[0021] Examples of extraction solvents include aqueous solvents, such as purified water and deionized water, aqueous solutions containing NaCl and other salts, such as physiological saline, acetone and other water-soluble organic solvents, and mixtures of alcohol and water. Examples of alcohols include ethanol, ethylene glycol, butylene glycol, and glycerin.

[0022] The pH of the aqueous medium may be acidic or alkaline. Examples of pH adjusters for aqueous solvents include organic acids such as adipic acid, citric acid, gluconic acid, succinic acid, acetic acid, tartaric acid, lactic acid, fumaric acid, and malic acid; inorganic acids such as phosphoric acid; and inorganic salts such as potassium carbonate, sodium carbonate, sodium bicarbonate, and phosphates (sodium salts, potassium salts, etc.). In addition, in order to maintain a constant pH, a buffer solution such as Tris-HCl buffer, HEPES buffer, phosphate buffer, acetate buffer, citrate buffer, or glycine-HCl buffer can also be used as the aqueous solvent.

[0023] The extraction method can be, for example, one or more methods selected from the group consisting of immersion extraction, pressure extraction, supercritical and sub-supercritical extraction methods. The extraction conditions may be any conditions that do not substantially impair the effects of the present invention. The extraction time is preferably 10 minutes to 24 hours. The extraction temperature is, for example, 4°C or higher, preferably 15°C or higher, and may be room temperature (25°C) or higher.

[0024] The extract obtained by extraction may be used as component (a) as is, or the obtained extract may be further purified or concentrated. Examples of purification and concentration methods include one or more methods selected from the group consisting of centrifugation, salting out, dialysis, vacuum concentration, ultrafiltration, gel filtration, ion exchange chromatography, and affinity chromatography. The purified or concentrated extract may be dried under reduced pressure or diluted with a solvent.

[0025] The content of component (a) in the oral composition is preferably 0.025% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.06% by mass or more, and may be, for example, 0.1% by mass or more, based on the total mass of the oral composition, thereby more effectively promoting the biofilm formation-reducing effect of the zinc compound of component (b). The content of component (a) in the oral composition is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less, based on the total mass of the oral composition, which can prevent discoloration of the composition, for example, at high temperatures or due to sunlight.

[0026] (ingredient (b)) Component (b) is a zinc compound. Component (b) may be, for example, a compound used in pharmaceuticals, foods, or cosmetics.

[0027] As component (b), for example, inorganic zinc salts such as zinc oxide (low-temperature calcined zinc oxide), zinc borate, zinc fluorosilicate, zinc fluoroborate, zinc carbonate, zinc fluoride, zinc iodate, zinc chloride, zinc sulfate, zinc nitrate, and zinc phosphate; and Examples of organic zinc salts include zinc acetate, zinc lactate, zinc butyrate, zinc formate, zinc citrate, zinc gluconate, zinc aspartate, zinc glutamate, zinc propionate, zinc oxalate, zinc phytate, zinc tartrate, zinc malate, zinc succinate, zinc malonate, zinc maleate, zinc benzoate, zinc salicylate, zinc fumarate, zinc glycerate, zinc glycerophosphate, zinc glycolate, zinc picolinate, zinc ascorbate, zinc bisglycinate, zinc lysinate, zinc methionine, zinc pyrrolidonecarboxylate, zinc p-phenolsulfonate, salts of saturated fatty acids having 10 to 24 carbon atoms (e.g., zinc laurate, zinc myristate, zinc palmitate, zinc stearate), salts of unsaturated fatty acids having 10 to 24 carbon atoms (e.g., zinc oleate, zinc undecylenate), and zinc lauroyl sarcosinate. These zinc salts may be hydrates.

[0028] Component (b) is preferably one or more compounds selected from the group consisting of zinc chloride, zinc gluconate, and zinc stearate, and more preferably zinc chloride, which can more stably improve the inhibitory effect on biofilm formation.

[0029] The content of component (b) in the oral composition is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more, based on the total oral composition. The content of component (b) in the oral composition is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less, based on the total mass of the oral composition, thereby reducing the metallic taste caused by the zinc compound.

[0030] The mass ratio ((b) / (a)) of the content of component (b) to the content of component (a) is preferably 0.1 or more and 20 or less, more preferably 4 or more and 12 or less. This makes it possible to more effectively suppress the formation of a biofilm. Furthermore, in order to more stably suppress the formation of biofilms, the mass ratio ((b) / (a)) is preferably 0.1 or more, more preferably 2 or more, and even more preferably 3 or more, and is preferably 22 or less, more preferably 20 or less, and even more preferably 12 or less.

[0031] Furthermore, the amount of component (a) to be applied to the oral cavity per day is preferably 0.01 g or more, more preferably 0.1 g or more, which can more reliably improve the inhibitory effect on biofilm formation. On the other hand, the daily application amount of component (b) can be set based on the above-mentioned daily application amount of component (a) so that the mass ratio ((b) / (a)) is preferably 0.1 or more and 20 or less. This allows for more stable improvement of the biofilm formation inhibitory effect. The oral composition may be applied to the oral cavity, for example, 1 to 10 times per day, preferably 1 to 5 times, and more preferably 1 to 3 times.

[0032] (Other ingredients) The oral composition may further contain components other than components (a) and (b). Such components may be selected depending on, for example, the intended use and dosage form. Other ingredients include, for example, medicinal ingredients, abrasives, binders, thickeners, humectants, surfactants, flavoring agents, preservatives, fragrances, colorants, pH adjusters, solvents, solubilizers, bases, detergents, adsorbents, etc., and can be selected appropriately depending on the dosage form, etc. Specific examples of added ingredients are shown below.

[0033] Examples of medicinal ingredients include one or more selected from the group consisting of bactericides, anti-inflammatory agents, blood circulation promoters, tartar deposition inhibitors, stain removers, hypersensitivity inhibitors, vitamins, and plaque-decomposing enzymes. These medicinal ingredients are not limited as long as they can be used in pharmaceuticals, oral compositions, etc.

[0034] Among the medicinal ingredients, examples of disinfectants include one or more selected from the group consisting of isopropylmethylphenol, cetylpyridinium chloride, cetylpyridinium chloride hydrate, benzalkonium chloride, benzethonium chloride (benzethonium chloride), hinokitiol, chlorhexidine hydrochloride, alkyldiaminoethylglycine hydrochloride, sodium lauroyl sarcosine, and triclosan.

[0035] Examples of anti-inflammatory agents include one or more selected from the group consisting of β-glycyrrhetinic acid, glycyrrhetinic acid, glycyrrhizinic acid, diammonium glycyrrhizinate, disodium glycyrrhizinate, trisodium glycyrrhizinate, dipotassium glycyrrhizinate (dipotassium glycyrrhizinate), monoammonium glycyrrhizinate, tranexamic acid, ε-aminocaproic acid, sodium azulene sulfonate hydrate, allantoin, allantoin dihydroxyaluminum, epidihydrocholesterol, dihydrocholesterol, and lysozyme hydrochloride.

[0036] The blood circulation promoter may be, for example, at least one selected from the group consisting of sodium chloride and tocopherol acetate.

[0037] Examples of tartar deposit inhibitors include one or more selected from the group consisting of zeolite, disodium hydrogen phosphate, disodium dihydrogen pyrophosphate, sodium pyrophosphate, anhydrous sodium pyrophosphate, tetrasodium pyrophosphate (anhydrous), disodium monohydrogen phosphate, sodium hydrogen phosphate hydrate, disodium hydrogen phosphate (crystalline), trisodium phosphate, and sodium polyphosphate.

[0038] Examples of stain removers include one or more selected from the group consisting of macrogol (Macrogol 200, Macrogol 300, Macrogol 400, Macrogol 600, Macrogol 1000, Macrogol 1500, Macrogol 1540, Macrogol 4000, Macrogol 6000, Macrogol 20000, etc.), sodium polyphosphate, and polyvinylpyrrolidone.

[0039] The dentin hypersensitivity reducing agent may be, for example, at least one selected from the group consisting of potassium nitrate and aluminum salts.

[0040] Examples of vitamin preparations include one or more selected from the group consisting of ascorbic acid, L-ascorbic acid, sodium ascorbate, L-sodium ascorbate, pyridoxine hydrochloride, DL-α-tocopherol acetate, tocopherol acetate, dl-α-tocopherol nicotinate, and tocopherol nicotinate.

[0041] An example of a plaque decomposing enzyme is dextranase.

[0042] Examples of the abrasive include one or more selected from the group consisting of silica-based abrasives such as silicic acid anhydride, silica (crystalline silica or amorphous silica), silica gel, and aluminosilicate; zeolite, calcium hydrogen phosphate anhydrate, calcium hydrogen phosphate dihydrate, calcium pyrophosphate, calcium carbonate, aluminum hydroxide, alumina, magnesium carbonate, magnesium triphosphate, zirconium silicate, calcium triphosphate, hydroxyapatite, calcium quaternary phosphate, and synthetic resin-based abrasives.

[0043] Examples of the binder include one or more selected from the group consisting of organic binders such as pullulan, gelatin, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium carboxymethyl cellulose, carrageenan, sodium alginate, xanthan gum, sodium polyacrylate, gum arabic, guar gum, locust bean gum, polyvinyl alcohol, polyvinylpyrrolidone, and carboxyvinyl polymers, thickening agents such as silicic anhydride, and bentonite.

[0044] The thickening agent may be any one that is commercially available as a pharmaceutical, food, or cosmetic ingredient, and specifically includes one or more selected from the group consisting of polyhydric alcohols, more specifically sorbitol, glycerin, concentrated glycerin, ethylene glycol, propylene glycol, 1,3-butylene glycol, propanediol (1,3-propanediol), polyethylene glycol, polypropylene glycol, xylitol, maltitol, lactite, trehalose, sodium hyaluronate, and hydrolyzed collagen.

[0045] The humectant may be any one that is commercially available as a pharmaceutical, food, or cosmetic ingredient, and specifically includes polyhydric alcohols, and more specifically includes one or more selected from the group consisting of sorbitol (sorbitol), glycerin, concentrated glycerin, diglycerin, ethylene glycol, propylene glycol, 1,3-butylene glycol, propanediol (1,3-propanediol), polyethylene glycol, polypropylene glycol, sodium hyaluronate, and hydrolyzed collagen.

[0046] Specific examples of the surfactant include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants, and preferably one or more surfactants selected from the group consisting of anionic surfactants, nonionic surfactants, and amphoteric surfactants.

[0047] Examples of anionic surfactants include one or more selected from the group consisting of N-acylamino acid salts, α-olefin sulfonates, N-acylsulfonates, alkyl sulfates (sodium lauryl sulfate, sodium laureth sulfate, etc.), and sulfates of glycerin fatty acid esters. Examples of nonionic surfactants include one or more selected from the group consisting of polyoxyethylene alkyl ethers (such as polyoxyethylene cetyl ether), polyoxyethylene-polyoxypropylene block copolymers, polyoxyethylene hydrogenated castor oils such as polyoxyethylene hydrogenated castor oil 60, polyoxyethylene ethers of glycerin esters, sucrose fatty acid esters, alkylolamides, and glycerin fatty acid esters (for example, polyglycerin fatty acid esters such as polyglyceryl-10 myristate and polyglyceryl-10 laurate). Examples of amphoteric surfactants include one or more selected from the group consisting of alkyl betaine surfactants, amine oxide surfactants, and imidazolinium betaine surfactants, and specific examples thereof include 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine and coconut oil fatty acid amido alkyl betaine.

[0048] Examples of flavoring agents include one or more selected from the group consisting of sodium L-glutamate, saccharin, saccharin sodium, disodium glycyrrhizinate, trisodium glycyrrhizinate, sodium chloride, sucrose, glucose, fructose, lactose, honey, aspartame, stevia, sucralose, xylitol, inositol, D-sorbitol, sorbitol liquid, D-mannitol, arabitol, raffinose, lactulose, lactitol, erythritol, reduced palatinose, palatinose, palatinit, acesulfame K, maltose, maltosyl trehalose or maltitol, neohesperidin dihydrochalcone, perillartine, p-methoxycinnamic aldehyde, and thaumatin.

[0049] Examples of preservatives include one or more selected from the group consisting of paraoxybenzoic acid esters such as sodium benzoate, methylparaben, ethylparaben, butylparaben, isopropylparaben, propylparaben, isobutylparaben, and benzylparaben; alcohols such as phenoxyethanol and ethanol; sorbic acid, benzoic acid, dehydroacetic acid, propionic acid, and salts thereof; ethylenediaminetetraacetate; and alkyldiaminoethylglycine hydrochloride.

[0050] The flavoring agent may be, for example, one or more selected from the group consisting of L-menthol, peppermint, spearmint, fruit flavorings, and peppermint oil.

[0051] Examples of coloring agents include natural colorants such as safflower red colorant, gardenia yellow colorant, gardenia blue colorant, perilla colorant, red koji colorant, red cabbage colorant, carrot colorant, hibiscus colorant, cacao colorant, spirulina blue colorant, and coumarind colorant; legal colorants such as Red No. 3, Red No. 104, Red No. 105, Red No. 106, Yellow No. 4, Yellow No. 5, Green No. 3, and Blue No. 1; and one or more selected from the group consisting of riboflavin and titanium dioxide.

[0052] Examples of pH adjusters include one or more selected from the group consisting of acids and alkalis, such as acetic acid, hydrochloric acid, sulfuric acid, nitric acid, citric acid, phosphoric acid, malic acid, gluconic acid, maleic acid, succinic acid, glutamic acid, pyrophosphoric acid, tartaric acid, sodium hydroxide acetate, potassium hydroxide, sodium acetate, sodium carbonate, sodium citrate, sodium hydrogen citrate, phosphoric acid, sodium phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate, and potassium dihydrogen phosphate, and buffers. The pH adjuster is preferably one or more selected from the group consisting of citric acid, phosphoric acid, and salts thereof. For example, the oral composition may contain sodium citrate and citric acid. Alternatively, the oral composition may contain a combination of sodium monohydrogen phosphate and sodium dihydrogen phosphate.

[0053] Examples of the solvent include water and lower alcohols such as ethanol and propanol. The oral composition may, for example, contain water and ethanol, or may, for example, contain water but not ethanol.

[0054] Solubilizers may be added to promote the dissolution of the additives and medicinal ingredients in water, for example. Examples of such solubilizers include polyhydric alcohols such as propylene glycol, dipropylene glycol, butylene glycol, and polyethylene glycol.

[0055] The base may be, for example, sodium bicarbonate.

[0056] Detergents include, for example, sodium polyphosphate.

[0057] Examples of adsorbents include β-cyclodextrin. Other adsorbents include copper gluconate. Component (b), such as one or more members selected from the group consisting of zinc chloride, zinc gluconate, and zinc stearate, is also expected to function as an adsorbent. The oral composition may contain, for example, component (b) and a copper compound, or may contain, for example, component (b) but no copper compound.

[0058] Furthermore, in addition to the above-mentioned components, components generally suitable for use in oral compositions can also be appropriately blended within the scope of the present invention.

[0059] (Manufacturing method) In this embodiment, the method for producing an oral composition includes, for example, a step of blending components (a) and (b) into an oral composition. Such a production method is preferably a method for producing an inhibitor of biofilm formation. The specific manufacturing procedure for the oral composition can be selected depending on, for example, the dosage form of the oral composition.

[0060] (Dosage form, etc.) Specific examples of oral compositions include one selected from the group consisting of dentifrices such as toothpaste, liquid dentifrice, and tooth powder; mouthwashes (mouth rinses); oral liniments such as oral gel preparations, oral ointments, oral pastes, and oral pastes; oral patches such as gum-adherent tape preparations; oral pills; oral tablets; oral powders; oral powders; oral liquids; oral suspensions; oral emulsions; oral granules; gums; lozenges; and buccal forms. In terms of more stably improving the inhibitory effect on biofilm formation, the oral composition is preferably a mouthwash (mouthwash, etc.) or a dentifrice (toothpaste, liquid dentifrice, etc.). Furthermore, the oral composition may be in the form of, for example, a liquid, semi-solid, or solid.

[0061] (Method for inhibiting biofilm formation) In this embodiment, the method for inhibiting biofilm formation includes applying the oral composition of this embodiment described above to the oral cavity. According to this method, the formation of biofilms in the oral cavity can be effectively suppressed. Furthermore, the above-mentioned suppression method specifically excludes medical procedures for humans.

[0062] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. [Example]

[0063] The present embodiment will be specifically described below with reference to examples, but the present embodiment is not limited to these examples.

[0064] (Examples 1 to 8 and Comparative Examples 1 to 10) In this example, an oral composition in the form of a mouthwash was prepared and evaluated by the method described below.

[0065] (Method for preparing oral composition) Each oral composition was obtained by mixing the components shown in Tables 1 to 3. Details of the components shown in the tables are given below. S. mutans (Sm): Cultured using the method described below. Extract of Millidae algae: Mirtect HS (manufactured by Ichimaru Falcos Co., Ltd.)

[0066] [Table 1]

[0067] [Table 2]

[0068] [Table 3]

[0069] (Cultivation of S. mutans bacteria) The following manipulations using bacteria were carried out anaerobically in a glove box (AS ONE #AS-600PC) in which the atmosphere was replaced with carbon dioxide. Ten mL of Gifu Anaerobic Medium (GAM medium, Nissui Pharmaceutical Co., Ltd., Cat. #05422) was dispensed into a disposable 15 mL centrifuge tube, and 0.2 mL of thawed frozen culture of Streptococcus mutans (ATCC 35668) was inoculated and cultured anaerobically at 37°C for 72 hours. Additionally, 180 μL of 2% sucrose-containing GAM medium was added to a 96-well plate (IWAKI), to which 20 μL of the culture medium was added and cultured anaerobically at 37°C for 24 hours. The medium in the wells was then removed, and 180 μL of 2% sucrose-containing GAM medium without the test substance (control) or the same medium containing the test substance dispersed or dissolved at the concentrations listed in Tables 1 to 3 was added. 20 μL of the pre-cultured culture was added, and the wells were cultured anaerobically at 37°C for 72 hours.

[0070] (Biofilm staining and calculation of biofilm formation rate) The medium was removed from each well, and 100 μL of crystal violet staining solution was added to each well. The wells were then left to stand for 20 to 30 minutes. Subsequently, the wells were washed twice with 200 μL of saline, and 100 μL of ethanol was added to each well. After shaking for 15 minutes, the absorbance at Abs 590 nm was measured using a plate reader. If the absorbance was 2.0 or higher, the measurement solution was diluted with ethanol as necessary. The test was performed with N=4, and the biofilm formation rate (%) was calculated from each absorbance result using the average value of the untreated control group (Comparative Example 1) as the standard, according to the following formula: Biofilm formation rate (%) = (absorbance of test substance group - blank) / (absorbance of control group - blank) * 100 The average value (N=4) of the biofilm formation rate (%) for each example is also shown in Tables 1 to 3.

[0071] (statistical analysis) For each test, intergroup comparisons were exploratory analyzed using Student's t-test. Figures 1 to 3 show the results of analyzing the biofilm formation rate for zinc chloride (Examples 1 and 2 and Comparative Examples 2 and 3), zinc gluconate (Examples 3 to 6 and Comparative Examples 4 to 8), and zinc stearate (Examples 7 and 8, Comparative Examples 4, 9, and 10), respectively. In Figures 1 to 3, *P<0.05 and **P<0.01 in comparison with the untreated control group. In comparison with the group to which each single component was added, the group to which a combination of an extract of Myrrhaceae algae (denoted as "Mirtect" in Figures 1 to 3) and a zinc compound was added showed # P<0.05, ## P<0.01. The "%" of the test substance concentration on the horizontal axis in Figures 1 to 3 is "% by mass."

[0072] As shown in Figure 1, when zinc chloride or an extract of Myridae algae was added alone, no reduction in biofilm formation rate was observed, while when zinc chloride and an extract of Myridae algae were combined, the biofilm formation rate was reduced despite the concentrations being lower than those of either compound alone, demonstrating a synergistic effect of zinc chloride and the extract of Myridae algae. Similarly, as shown in Figure 2, zinc gluconate alone exhibited a biofilm formation inhibitory effect, but when added in combination with an extract of Myridae algae, the inhibitory effect was improved at all concentrations. Furthermore, as shown in Figure 3, zinc stearate also exhibited a higher inhibitory effect than when an extract of Myridae algae was added alone (Comparative Example 4), demonstrating a synergistic biofilm inhibitory effect with the extract of Myridae algae. Therefore, it is believed that by combining a zinc compound with an extract of the Myridae family, a biofilm inhibitory effect can be obtained that cannot be obtained by either compound alone.

[0073] (Formulation Examples 1 to 12) Table 4 shows examples of formulations for oral compositions.

[0074] [Table 4]

Claims

1. An oral composition comprising the following components (a) and (b) as active ingredients: (a) Extract of Millidae algae (b) Zinc compounds

2. 2. The oral composition according to claim 1, wherein the component (b) is one or more compounds selected from the group consisting of zinc chloride, zinc gluconate, and zinc stearate.

3. 3. The oral composition according to claim 1, wherein the mass ratio ((b) / (a)) of the content of component (b) to the content of component (a) is 0.1 or more and 20 or less.

4. 3. The oral composition according to claim 1, wherein the content of component (a) in the oral composition is 0.025% by mass or more and 1% by mass or less based on the total oral composition.

5. The oral composition according to claim 1 or 2, which is an inhibitor of biofilm formation.

6. The oral composition according to claim 1 or 2, which is a mouthwash or a dentifrice.

7. A method for inhibiting biofilm formation, comprising applying the oral composition according to claim 1 or 2 to the oral cavity.

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