Anti-caries oral hygiene composition

Abstract

The present invention primarily relates to an oral hygiene composition comprising one or more specific essential oil(s) and / or essential oil component(s) asserting a antibacterial effect against Streptococcus mutans. The invention further relates to a use of said oral hygiene composition to assert an antibacterial effect against Streptococcus mutans and to reduce lactic acid concentration in the oral cavity. The invention also relates to a method of increasing oral hygiene. Further, the invention relates to an oral hygiene composition for use in a method of preventing, mitigating and / or treating a dental plaque-associated disease or condition.

Description

[0001] Munich, 21 October 2024

[0002] our Ref.: SM 6924-01 WO SOE / swo / nze

[0003] Applicant / Proprietor: Symrise AG

[0004] Application No.: New application

[0005] Symrise AG

[0006] MiihlenfeldstraBe 1 , 37603 Holzminden, Germany

[0007] Anti-caries oral hygiene composition

[0008] The present invention primarily relates to an oral hygiene composition comprising one or more specific essential oil(s) and / or essential oil component(s) asserting an antibacterial effect against Streptococcus mutans. The invention further relates to a use of said oral hygiene composition to assert an antibacterial effect against Streptococcus mutans and to reduce lactic acid concentration in the oral cavity. The invention also relates to a method of increasing oral hygiene. Further, the invention relates to an oral hygiene composition for use in a method of preventing, mitigating and / or treating a dental plaque-associated disease or condition.

[0009] Further aspects of the present invention will arise from the description below, in particular from the examples, as well as from the attached patent claims.

[0010] Oral caries, commonly known as tooth decay, is an endogenous infection affecting the calcified tissues of the teeth. This condition arises from the demineralization of these tissues by organic acids produced by plaque bacteria that ferment dietary carbohydrates. Despite significant advances in dental care, caries remains one of the most prevalent chronic diseases worldwide, posing a substantial burden on national healthcare systems. Environmental factors, including diet, oral hygiene habits, and stress, significantly influence the development of tooth decay. Among these, the most critical factor in caries epidemiology is sugar consumption. Plaque bacteria, such as Streptococcus mutans (S. mutans), Streptococcus sobrinus, Lactobacilli, and Actinomyces, metabolize dietary fermentable carbohydrates on tooth surfaces to produce acids. These acids trigger local enamel demineralization, leading to the formation of microcavities.

[0011] Research has demonstrated that the drop in plaque pH is largely due to lactic acid production by plaque bacteria, with S. mutans being a major contributing force. S. mutans lacks a respiratory chain and generates ATP through glycolysis, producing lactate as the primary end-product in the presence of excess glucose. After food ingestion, the sugar levels available to oral bacteria can rise significantly, shifting the fermentation pattern of S. mutans from mixed acid production to predominantly lactic acid. Thus, the ability of S. mutans to consistently lower pH through lactic acid production is a critical factor in its role in dental caries (Dashper & Reynolds, Lactic acid excretion by Streptococcus mutans, Society for General Microbiology (1996), 142, 1).

[0012] Tooth enamel is composed of 96% minerals, primarily hydroxyapatite and calcium phosphate salts, which become soluble when exposed to acidic environments. Enamel demineralization begins at a pH of 5.5. Initially, caries progresses slowly, and a carious lesion can remain stable for months or even years, allowing for potential remineralization. However, if the demineralization continues unchecked, the lesion can progress to cavitation, where the enamel and dentin are destroyed, resulting in cavities.

[0013] Thus, while caries is a polymicrobial disease, targeting S. mutans may offer an innovative solution for effective prevention. S. mutans, an early colonizer, plays a central role in forming cariogenic biofilms termed plaque, contributing to the persistence and resilience of these biofilms while promoting an acidic environment that leads to demineralization. Understanding the biology of S. mutans is crucial, as it is one of the most extensively studied bacteria associated with the cariogenic potential of biofilms.

[0014] Fluoride continues to be the single most important anti-caries agent in dental care. When combined with stringent oral hygiene practices, it strengthens the tooth enamel, making it more resistant to acid attacks from plaque bacteria.

[0015] In contrast to fluoride, which solely acts as a protecting and remineralizing agent, a complementary approach would be inhibiting the growth of caries-inducing bacteria, specifically S. mutans, which is known for its role in acidification and the cariogenic potential of biofilms. By targeting S. mutans, the initial formation and persistence of cariogenic biofilms may be disrupted, thereby reducing their acid production and subsequent demineralization of tooth enamel. This could involve the development of antimicrobial agents or probiotic treatments specifically designed to inhibit S. mutans growth without disrupting the balance of the oral microbiome. Such targeted interventions could enhance current preventive strategies, providing a complementary approach to fluoride-based treatments and significantly reducing the incidence of caries. Importantly, the specific targeting of S. mutans addresses the primary causative factors of dental plaque-associated diseases, rather than solely treating the resultant conditions such as enamel demineralization and oral cavity infections.

[0016] By focusing on an early colonizers and key contributors to biofilm formation, such as S. mutans, this approach offers a promising avenue for more effective caries prevention, mitigation and treatment, as well as for addressing dental plaque-associated conditions and diseases, which focuses on the root cause of the disease and minimizes its prevalence and impact on public health.

[0017] Therefore, there is a need to compliment the remineralization effect of fluoride by developing a complementary anti-cariogenic solution. Such solution aims to reduce or inhibit the quantities of cariogenic bacteria, specifically S. mutans, while simultaneously interfering with local pH reduction in the oral cavity caused by fermentative bacteria. By addressing these aspects, a more comprehensive approach to caries prevention should be provided, alleviating the significant burden of this prevalent chronic disease on national healthcare systems.

[0018] The most widely established method to prevent and eliminate dental biofilm is through mechanical removal using dentifrices. These oral hygiene products typically contain triclosan, fluoride, cetylpyridinium chloride, and chlorhexidine gluconate. However, these ingredients can cause negative side effects, such as enamel discoloration and taste alterations. Fluoride-containing oral hygiene products are particularly problematic for children due to the risk of excessive fluoride ingestion, which can lead to dental fluorosis — a condition characterized by hypomineralization of the enamel. The severity of dental fluorosis is directly linked to the amount of fluoride ingested, with a higher prevalence in the permanent teeth of children with low weight or malnutrition (Wong et al., Topical fluoride as a cause of dental fluorosis in children, Cochrane Database Syst Rev (2010), 2010(1)) Natural antimicrobial compounds such as specific essential oils and / or their components have the potential to become a promising addition to fluoride containing oral hygiene products for reducing the risk of oral diseases in both children and adults.

[0019] Thus, there is a high need for the development of natural products that effectively prevent and control oral pathologies, which is essential for identifying safe alternatives that promote oral health.

[0020] However, there are also significant disadvantages to consider when applying essential oils or their components to the sensitive environment of the oral cavity. Some individuals may experience allergic reactions or sensitivities to certain essential oils, leading to irritation or adverse effects in the oral cavity. The effectiveness of essential oils can vary depending on their concentration, formulation, and the specific bacterial strains present, resulting in inconsistent results. The strong taste and sensation of some essential oils might be unpleasant or overwhelming for certain users, potentially discouraging regular use.

[0021] De Oliveira Carvalho et al tested cinnamon, clove, oregano, and thyme essential oils, along with toothpastes formulated with these natural products, demonstrated some antibiofilm and antibacterial activities against cariogenic bacteria. Notably, cinnamon essential oil and toothpastes containing combinations of clove, oregano, and thyme essential oils showed effectiveness in inhibiting S. mutans growth and disrupting preformed S. mutans biofilms, (de Oliveira Carvalho et al., In vitro anticariogenic and antibiofilm activities of toothpastes formulated with essential oils, Archives of Oral Biology (2020), 117, 104834).

[0022] However, the study did not address the problem that essential oils tend to indiscriminately eradicate bacteria in the oral cavity, lacking the discernment to differentiate between effects on beneficial and pathological bacterial strains.

[0023] The oral microbiome is a complex and delicate ecosystem composed of both beneficial and pathogenic microorganisms. The beneficial bacteria play crucial roles in maintaining oral health, including preventing colonization by harmful pathogens, supporting the immune response, and contributing to the overall balance of the oral environment. When essential oils eliminate both harmful and beneficial bacteria without discrimination, they can disrupt this delicate balance, potentially leading to negative consequences such as increased susceptibility to infections, oral diseases, and a compromised immune response. Thus, an indiscriminate antibacterial action of certain essential oils poses a significant threat to the oral microbiome, potentially leading to far-reaching pathological consequences (Sedghi et al., The oral microbiome: Role of key organisms and complex networks in oral health and disease, Periodontal 2000 (2021), 87(1): 107-131).

[0024] It is therefore imperative to meticulously identify essential oils or their specific components that can target specific pathogenic microbes. Additionally, it is crucial to determine concentrations that do not adversely affect the growth of beneficial bacterial communities in the oral cavity. This careful selection and precise application are essential to preserving the delicate balance of the oral microbiome, ensuring that oral health is maintained without compromising the beneficial bacterial populations that are vital for overall oral health.

[0025] As a conclusion, there is a persistent and critical need for agents with specific antibacterial activity against S. mutans, preferably without equally disturbing the beneficial oral microbiome. Further (preferred) aspects of the problem underlying the present invention are apparent in view of the above.

[0026] This problem (as well as the additional aspects to be considered in connection therewith) is solved by the present invention by providing an oral hygiene composition with selected essential oils and / or essential oil components at effective concentrations.

[0027] Surprisingly, it was found that the stated objects are achieved by providing an oral hygiene composition comprising one or more specific essential oils and / or essential oil components in concentrations sufficient to achieve an antibacterial effect against Streptococcus mutans. In the present invention, from a screening of approximately 500 substances for their in vitro minimal inhibitory concentration (MIC) for completely inhibiting the growth of S. mutans, ten substances with superior activity were identified and subsequently tested in an ex vivo cariogenic biofilm model. The tested substances demonstrated a beneficial profile by reducing the bacterial load of cariogenic S. mutans without impacting the overall bacterial quantities in the biofilm. Additionally, some of these substances interfered with lactate production, a well-known surrogate for cariogenic pH that results in demineralization.

[0028] According to a first aspect of the present invention, the stated objects are achieved by providing an oral hygiene composition comprising at least one essential oil and / or essential oil component, wherein the total amount of the at least one essential oil and / or the at least one essential oil component present in the oral hygiene composition is sufficient to achieve a growth inhibitory effect against Streptococcus mutans, wherein the at least one essential oil and / or the at least one essential oil component is selected from the group consisting of amyris oil, cabreuva oil, paradol, bisabolol and farnesol, wherein, if respectively present, the concentration of amyris oil is 30 to 200 ppm, preferably 50 to 150 ppm, more preferably 64 to 128 ppm, and / or cabreuva oil is 30 to 200 ppm, preferably 50 to 150 ppm, more preferably 64 to 128 ppm, and / or paradol is 30 to 200 ppm, preferably 50 to 150 ppm, more preferably 64 to 128 ppm, and / or bisabolol is 30 to 200 ppm, preferably 50 to 150 ppm, more preferably 64 to 128 ppm, and / or farnesol is 5 to 100 ppm, preferably 10 to 50 ppm, more preferably 16 to 32 ppm, in each case based on the total amount of the composition.

[0029] An antibacterial effect refers to the ability of substances or substance mixtures (or, respectively, in the context of the present invention preferably to a total amount of at least one essential I essential oil component) to inhibit the growth, replication, or activity of bacteria. This effect can range from slowing bacterial proliferation (bacteriostatic) to killing the bacteria (bactericidal), depending on the concentration and mode of action of the substance. Preferably, an antibacterial effect may not necessarily eradicate bacteria but can significantly reduce their population and growth.

[0030] Essential oils are concentrated, volatile aromatic compounds extracted from plants, typically through distillation or mechanical methods. These oils capture the plant's scent and flavour, also known as its "essence," and are composed of a variety of components, prevalently organic compounds such as terpenes, esters, aldehydes, and alcohols. Essential oils and / or essential oil components are used in various applications, including aromatherapy, cosmetics, personal care products, and as natural remedies for their therapeutic properties.

[0031] Amyris oil is an essential oil derived from the wood of the Amyris balsamifera tree.

[0032] JP 2012-229191 A claims a list of essential oils effective against bacteria of the genus Streptococcus, specifically mentioning amyris oil as a solution containing sesquiterpenes candidates exclusively for biofilm disruption. However, the description advises against using bactericidal agents due to potential general side effects.

[0033] Cabreuva oil is a type of essential oil derived from the wood of the Myrocarpus fastigiatus tree. It is commonly used in aromatherapy and perfumery due to its calming effects.

[0034] Paradol is a bioactive compound found primarily in ginger and related plants, known for its pungent flavour. Chemically, it is a ketone that contributes to the spicy taste of ginger and other Zingiberaceae family members. Paradol has been studied for its potential health benefits, including anti-inflammatory, antioxidant, and anticancer properties. Paradol as disclosed herein has the CAS (Chemical Abstracts Service) number 27113-22-0.

[0035] Bisabolol is a naturally occurring, colorless, viscous oil derived primarily from the German chamomile plant and the candeia tree. It is a monocyclic sesquiterpene alcohol known for its soothing, anti-inflammatory, and antimicrobial properties. Bisabolol is widely used in cosmetics and personal care products for its ability to enhance skin penetration, reduce irritation, and support the healing of damaged skin.

[0036] US 2009 / 0238905 focuses on reducing inflammation using synergistic mixtures comprising bisabolol, parabol and ginger extracts, specifically for the lower respiratory tract and the lower gastrointestinal tract. The patent application makes no mention of applications related to dental plaque, nor does it address the use of these mixtures against S. mutans.

[0037] DE 195 06 706 relates to an oral spray with caries-preventive and gum-care effects, characterized by containing bicarbonate, hydrogen phosphate, and 0.1 to 0.2% bisabolol in an orally compatible flavoured solvent mixture. However, the patent does not specify the microbial targets, and the bisabolol concentration significantly exceeds the levels claimed and disclosed in the present invention.

[0038] Bisabolol as disclosed herein has the CAS number 23089-26-1.

[0039] Farnesol is a natural organic compound classified as a sesquiterpenoid alcohol. It is characterized by its floral, citrus-like aroma and is commonly found in essential oils of plants such as citronella, neroli, cyclamen, lemon grass, tuberose, rose, and musk. Farnesol is used in perfumery and cosmetics for its fragrance.

[0040] Farnesol as disclosed herein has the CAS number 4602-84-0.

[0041] All above mentioned essential oils or essential oil components showed a high reduction of S. mutans bacterial load in relation to total bacterial reduction in the biofilm model presented in Example 3 and illustrated in the diagram of FIG. 1. Specifically, paradol, bisabolol, amyris oil, cabreuva oil and farnesol strongly diminished the population size of S. mutans in the biofilm model.

[0042] Bisabolol, amyris oil, and cabreuvaoil had the strongest diminishing effect on S. mutans counts in the biofilm model by at least 2 log units of CFU per biofilm, as indicated in FIG 3. Surprisingly, the quantity of Streptococcus mutans CFU was significantly impacted by the test substances in an advanced dental biolfilm model as presented in Examples 1 to 3, with several demonstrating more than a 1 log reduction in CFU counts. Notably, bisabolol, 1.28% Amyris oil, 1.28% Cabreuva oil and 0.32% farnesol exhibited the highest reductions in S. mutans counts. FIG 1 illustrates that all test substances decreased the relative abundance of S. mutans in the biofilms. Among these, bisabolol, amyris oil, cabreuva oil and farnesol were particularly effective in comparably low concentrations, indicating their strong antimicrobialproperties against S. mutans. The efficacy of these natural oils underscores their potential as valuable components in oral hygiene formulations aimed at reducing pathogenic bacteria and improving oral health.

[0043] Advantageously, according to the present invention, the aforementioned essential oils and their components, including bisabolol, amyris oil, cabreuva oil and farnesol, can exhibit specific, concentration-dependent growth inhibitory activity against S. mutans. This targeted action effectively reduces the population of this primary contributor to dental caries without causing significant disruption to the broader oral microbiome. Their selective antimicrobial properties ensure that beneficial bacteria remain largely unaffected, thereby maintaining the natural balance of the oral microbiome while preventing the proliferation of harmful pathogens.

[0044] In one embodiment there is provided an oral hygiene composition according to the present invention, wherein the composition is an oral care product selected from the group consisting of mouthwash, dental gel, toothpaste, tooth cream, toothpaste powder, oral spray, lozenge and chewing gum.

[0045] One of the significant benefits of essential oils is their accessibility and convenience. They can be easily incorporated into various oral care products, such as toothpastes and mouthwashes, making them convenient for daily use. For those seeking natural alternatives, essential oils reduce reliance on synthetic chemicals in oral care products. Moreover, the pleasant flavours and aromas of many essential oils may enhance the sensory experience of oral hygiene routines.

[0046] Mouthwashes are typically categorized into cosmetic or therapeutic products. Cosmetic mouthwashes temporarily mask bad breath through flavour compositions that provide a fresh, invigorating sensation. In contrast, therapeutic mouthwashes contain active ingredients designed to aid in mechanical control and maintain oral health. Various formulations, such as delmopinol, hexetidine, povidone-iodide, chlorhexidine gluconate, cetylpyridinium chloride, and hydrogen peroxide, have demonstrated efficacy in several systematic reviews. These reviews indicate that mouthwashes improve clinical parameters, including the plaque index and gingival inflammation, without causing microbial resistance or altering the microbial flora (Takenaka et al., Evidence-based strategy for dental biofilms: Current evidence of mouthwashes on dental biofilm and gingivitis, Japanese Dental Science Review (2019), 55, 1 , 33-40).

[0047] Chewing gums or dental care chewing gums may comprise a chewing gum base comprising elastomers, e.g. polyvinyl acetate (PVA), polyethylene, (low or medium molecular) polyiso butane (PIB), polybutadiene, isobutene / isoprene copolymers, polyvinyl ethyl ether (PVE), polyvinyl butyl ether, copolymers of vinyl esters and vinyl ethers, styrene / butadiene copolymers (SBR) or vinyl elastomers, e.g. based on vinyl acetate / vinyl laurate, vinyl acetate / vinyl stearate or ethylene / vinyl acetate and mixtures of the mentioned elastomers as e.g. described in EP 0242325, US 4,518,615, US 5,093,136, US 5,266,336, US 5,601 ,858 or US 6,986,709. Additionally chewing gum bases may contain further ingredients, e.g. (mineral) filers, e.g. calcium carbonate, titanium dioxide, silicone dioxide, talcum, aluminium oxide, dicalcium phosphate, tricalcium phosphate, magnesium hydroxide and mixtures thereof, plasticisers (e.g. lanolin, stearic acid, sodium stearate, ethyl acetate, diacetin (glycerol diacetate), triacetin (glycerol triacetate) and trietyhl citrate), emulsifiers (e.g. phosphatides, such as lecithin and mono and diglycerides of fatty acids, e.g. glycerol monostearate), antioxidants, waxes (e.g. paraffine waxes, candelilla waxes, carnauba waxes, microcrystalline waxes and polyethylene waxes), fats or fatty oils (e.g. hardened (hydrogenated) plant animal fats) and mono, di or triglycerides.

[0048] In one embodiment there is provided an oral hygiene composition according to the present invention comprising at least one substance selected from the group consisting of carriers, binders, abrasives, detergents, dyes, polishes, surfactants, humectants, thickening agents, sweeteners, aroma, aroma substances, flavourings, taste correcting agents, cooling agents, stabilizers, fluorine source, whitening agents, ethereal oils, emulsifiers, astringents and toning dry extracts, caries inhibiting additives and flavour correctants.

[0049] Preferably, the oral hygiene composition according to the invention is in the form of an oral care product from the group consisting of tooth paste, tooth powder, tooth gel, tooth cleaning liquid, tooth cleaning foam, mouth wash, mouth rinse, mouth spray, dental floss, chewing gum and lozenges. Such compositions or products may contain abrasive systems (abrasive and / or polishing components) such as silicates, calcium carbonate, calcium phosphate, aluminium oxide and / or hydroxyl apatite, surfactants such as e.g. sodium lauryl sulfate, sodium lauryl sarcosinate and / or cocamidopropyl betaine, humectants such as glycerol and / or sorbitol, thickening agents, e.g. carboxy methyl cellulose, poly ethylene glycols, carrageenans and / or Laponite® , sweeteners such as saccharine, aroma and taste correcting agents for unpleasant taste impressions, taste modifying substances (e.g. inositol phosphate, nucleotides, e.g. guanosine monophosphate, adenosine monophosphate or other substances, e.g. sodium glutamate or2-phenoxy propionic acid), cooling agents such as menthol derivates (e.g. L-mentyl lactate, L-menthyl alkyl carbonate, menthone ketals), icilin and icilin derivates, stabilizers and active agents such as sodium fluoride, sodium monofluoro phosphate, tin difluoride, quarternary ammonium fluorides, zinc citrate, zinc sulfate, tin pyrophosphate, tin dichloride, mixtures of different pyrophosphates, triclosane, cetyl pyridinium chloride, aluminum lactate, potassium citrate, potassium nitrate, potassium chloride, strontium chloride, hydrogen peroxide, aroma substances, sodium bicarbonate and / or smell correcting agents.

[0050] An oral hygiene composition according to the present invention may also be coated or encapsulated.

[0051] Encapsulation of the composition according to the invention may offer the advantage of controlled release, such as activation upon contact with water, or continuous release over an extended period. Additionally, encapsulation can protect the composition from degradation, thereby improving the product's shelf life. Methods for encapsulating active ingredients are well established in the field, with various encapsulation materials and techniques available to meet specific requirements.

[0052] The oral hygiene composition according to the present invention may advantageously be included in a variety of oral care products and confer its health-promoting effects on such products.

[0053] An oral hygiene composition according to the present invention may comprise one or more components selected from the group consisting of excipients and additional active ingredients. These active ingredients can include non-steroidal antiphlogistics, antibiotics, steroids, anti-TNF-alpha antibodies, other biotechnologically produced active agents, analgesics, dexpanthenol, prednisolone, polyvidone iodide, chlorhexidine-bis-D-gluconate, hexetidine, triclosan, benzydamine HCI, lidocaine, benzocaine, macrogol lauryl ether, benzocaine combined with cetidyl pyridinium chloride, or macrogol lauryl ether combined with protein-free hemodialysate from calf blood. The composition may also include fillers such as cellulose and calcium carbonate, plasticizers or flow improvers like talcum and magnesium stearate, coatings such as polyvinyl acetate phthalate and hydroxyl propyl methyl cellulose phthalate, disintegrants like starch and cross-linked polyvinyl pyrrolidone, softeners such as triethyl citrate and dibutyl phthalate, granulation substances like lactose and gelatin, retardation agents like poly(meth)acrylic acid methyl / ethyl / 2-trimethyl aminomethyl ester copolymerizates in dispersion and vinyl acetate / crotonic acid copolymerizates, compaction agents like microcrystalline cellulose and lactose, solvents and suspending or dispersing agents such as water and ethanol, emulsifiers like acetyl alcohol, lecithin, sodium lauryl sulfate, and PEG 40 hydrogenated castor oil. Additionally, it may include substances for modifying rheological properties like silica and sodium alginate, microbial stabilizers such as benzalkonium chloride, potassium sorbate, and sodium benzoate, preservatives and antioxidants like DL-alpha-tocopherol and ascorbic acid, pH modifiers such as lactic acid and citric acid, blowing agents or inert gases like fluorinated chlorinated hydrocarbons and carbon dioxide, dyes such as iron oxide and titanium oxide, and basic ingredients for ointments like paraffins and beeswax. Other components can be found in literature sources such as Schmidt and Christin's "Wirk- und Hilfsstoffe fur Rezeptur, Defektur und GroBherstellung" (1999) or Bauer, Fromming, and Fuhrer's "Lehrbuch der Pharmazeutischen Technologie" (8th edition, 2006).

[0054] In one embodiment there is provided an oral hygiene composition, comprising one or more essential oil(s) wherein the at least one essential oil is amyris oil, preferably present in 30 to 200 ppm, preferably 50 to 150 ppm, more preferably 64 to 128 ppm, based on the total amount of the composition.

[0055] In one embodiment there is provided an oral hygiene composition comprising one or more essential oil component(s), wherein the at least one essential oil component is bisabolol, preferably present in 30 to 200 ppm, preferably 50 to 150 ppm, more preferably 64 to 128 ppm, based on the total amount of the composition.

[0056] A second aspect relates to a use of the oral hygiene composition to achieve an antibacterial effect against Streptococcus mutans.

[0057] Preferably, the use of the oral hygiene composition aligns with the typical applications of an oral care product known in the art, tailored to the specific mode of application. Preferably, the use of the oral hygiene composition includes an extended incubation period within the oral cavity, optimized for the specific oral care product according to the present invention, to enhance the antibacterial effect.

[0058] A third aspect relates to a use of the oral hygiene composition to decrease lactic acid concentration in the oral cavity.

[0059] Preferably, the use of the oral hygiene composition includes an incubation step within the oral cavity optimized for the specific oral care product according to the present invention, allowing prolonged contact with the oral surface to achieve an elevation in pH.

[0060] An extended incubation period allows the antibacterial agent to penetrate deeper into biofilms and dense bacterial colonies. Biofilms, as structured communities of bacteria enclosed in a self-produced polymeric matrix, are notoriously resistant to antimicrobial agents. Extended contact time helps the agent to infiltrate the biofilm matrix and reach bacteria embedded deep within it. Further, incubation ensures that the antibacterial agent has sufficient time to reach all areas of the treated surface. This is particularly beneficial in complex environments like the oral cavity, where bacteria can reside in inaccessible regions such as interproximal spaces, gingival crevices, and on the surface of the tongue

[0061] A fourth aspect relates to a use of the oral hygiene composition to decrease lactic acid concentration in the oral cavity, wherein the composition additionally comprises elemol, or use of elemol in an oral hygiene composition for decreasing lactic acid concentration in the oral cavity, preferably wherein elemol is present in a concentration of 10 to 100 ppm, preferably 20 to 80 ppm, more preferably 32 to 64 ppm, in each case based on the total amount of the composition.

[0062] Elemol is a natural sesquiterpene alcohol found in the essential oils of certain plants, particularly within the genus Elemi. It is known for its woody and citrusy aroma, contributing to the fragrance of these oils. Elemol possesses various biological activities, including antiinflammatory, and antioxidant effects.

[0063] JP-2001 002542 A claims elemol in a list of other substances as an antibacterial component of a composition. However, a modification of pH or an effect in reduction on lactic acid concentration is also not mentioned once in the patent application. Advantageously, amyris oil, bisabolol and elemol show a distinct reduction of lactic acid concentration by at least 1-2 mmol / L in the biofilm model as presented in Example 3, and as shown in the resulting diagram in FIG 4.

[0064] Lactic acid, produced primarily by the metabolic activities of cariogenic bacteria such as S. mutans, lowers the pH in the oral cavity, creating an acidic environment that promotes the demineralization of tooth structures. Demineralization occurs when the acidic environment dissolves the mineral content of enamel and dentin, leading to the formation of cavities and the progression of dental caries. By reducing lactic acid levels, the pH of the oral environment is elevated, shifting from an acidic to a more neutral state. This shift inhibits the demineralization process and promotes remineralization, where minerals such as calcium and phosphate are redeposited into the tooth structure, leading to strengthening and repairing enamel and dentin.

[0065] A fifth aspect relates to a method for increasing oral hygiene, the method comprising: (i) applying an effective amount of the oral hygiene composition according to the present invention to the oral cavity; and (ii) allowing the composition to contact an oral surface for a period sufficient to exert a antibacterial effect against Streptococcus mutans.

[0066] The term "oral surface" encompasses all anatomical structures within the oral cavity that come into contact with ingested substances. This includes the teeth, the gingiva (gums), the tongue, the buccal mucosa, and the palate, comprising the anterior hard palate and the posterior soft palate.

[0067] One embodiment relates to a method according to the previous aspect, wherein the application of step (i) is brushing, rinsing, spraying, sucking and / or chewing.

[0068] Advantageously, combining the application of the oral hygiene composition with mechanical forces can significantly enhance its antibacterial efficacy. This approach facilitates the distribution of the antimicrobial agents to inaccessible areas within the oral cavity, such as interproximal spaces and gingival sulci. The mechanical force helps disrupt biofilms and physically dislodge microbial colonies, thereby allowing the antibacterial agents to penetrate more effectively and exert their full antimicrobial potential.

[0069] A sixth aspect relates to an oral hygiene composition for use in a method of preventing, mitigating and / or treating a dental plaque-associated disease. Dental plaque is a complex microbial biofilm that forms on the tooth surface, consisting of a diverse community of microorganisms embedded in an extracellular matrix of polymers from both host and microbial origins. This biofilm is not merely a collection of individual bacteria but a well-coordinated, spatially organized, and metabolically integrated microbial community. The formation of dental plaque begins with the adsorption of a conditioning film, known as the acquired pellicle, on the tooth surface immediately after cleaning. This pellicle influences the pattern of microbial colonization. Oral bacteria, including notable early colonizers like Streptococcus mutans, are then transported to the tooth surface, where they initially adhere reversibly through weak long-range interactions. This is followed by stronger, specific short-range interactions that lead to irreversible attachment. Subsequent stages involve the co-adhesion of later colonizers to the already attached early colonizers through specific interbacterial interactions. This increases the biofilm's diversity and leads to the formation of complex structures. Finally, the attached microorganisms multiply, forming a three-dimensional, spatially organized biofilm with a complex extracellular matrix that provides structural integrity and resistance to antimicrobial agents (Marsh P.D., Dental plaque as a Microbial biofilm, Caries Res (2004), 38:204-211).

[0070] The ecological plaque hypothesis posits that alterations in the microenvironment surrounding the dental plaque biofilm are the driving force behind dental diseases, including dental caries and periodontal diseases. This theory highlights how environmental shifts, such as changes in pH, nutrient availability, and oxygen levels, can disrupt the microbial balance within the plaque, leading to the proliferation of pathogenic bacteria, such as S. mutans and the onset of disease (Senivirathne et al., Dental plaque biofilm in oral health and disease, The Chinese Journal of Dental Research (2011), 14, 2, 87-94)

[0071] Thus, it is established knowledge in the art that S. mutans is suitable therapeutic target in preventing, mitigating and / or treating dental plaque-associated diseases.

[0072] One embodiment relates to an oral hygiene composition for use in a method according to the previous aspect, wherein the dental plaque-associated disease is selected from the group of dental caries, tooth abscesses and tooth loss.

[0073] It is long-standing knowledge in the art that targeting S. mutans is a highly effective strategy for caries prevention. While dental caries is a polymicrobial disease, selectively targeting S. mutans in dental biofilms is considered a promising strategy for prevention. This approach is particularly effective because S. mutans synthesizes insoluble glucans from sucrose, which are crucial for forming a stable biofilm matrix. This matrix not only facilitates bacterial colonization on the tooth surface but also acts as a diffusion barrier, maintaining the acidic environment in which cariogenic bacteria thrive. A prevailing theory in dental caries prevention is that by specifically targeting S. mutans, the development of cariogenic biofilms can be halted without disrupting the health-associated oral microbiome (Lemos et al., The Biology of Streptococcus mutans, American Society for Microbiology (2019), 7:10.1128).

[0074] Localized destruction of tooth tissues occurs due to bacterial activity, where microbial acids demineralize enamel or cementum. The initial caries lesion forms beneath the surface as acid diffuses into the tooth. Clinically detectable as a white spot, this early stage can be reversed through remineralization and the regrowth of hydroxyapatite crystals, a process enhanced by fluoride. If untreated, caries advance, leading to irreversible cavitations that penetrate the dentin and eventually reach the pulp chamber. This progression ultimately causes necrosis and periapical abscesses, ultimately leading to tooth abscesses and tooth loss (Ozdemir et al., Dental Caries: The Most Common Disease Worldwide and Preventive Strategies, International Journal of Biology (2013), 5(4))

[0075] One embodiment relates to an oral hygiene composition for use in a method of mitigating and / or preventing a dental plague-associated condition, wherein the dental plaque-associated condition is selected from the group of gingivitis, periodontitis, gum recession, and halitosis.

[0076] The present invention also relates to the non-medical use of an oral hygiene composition as defined above for mitigating and / or preventing a dental plague-associated condition.

[0077] Gingivitis, periodontitis, and gum recession are interrelated conditions affecting the gums and supporting structures of the teeth. Gingivitis is the initial stage of gum disease, characterized by inflammation of the gums due to plaque build-up. Symptoms include red, swollen gums that may bleed during brushing or flossing. This condition is primarily caused by bacterial plaque, which includes bacteria such as S. mutans. If left untreated, gingivitis can progress to periodontitis, a more severe form of gum disease.

[0078] Periodontitis involves deeper infection and inflammation, leading to the destruction of the supporting structures of the teeth, including the periodontal ligament and alveolar bone. The bacterial community in periodontitis is more complex and pathogenic, with bacteria such as Porphyromonas gingivalis playing a significant role. This advanced stage of gum disease results in the formation of periodontal pockets and significant tissue damage. It was shown that increased colonization of S. mutans was observed in individuals with chronic periodontitis, both in saliva and sub-gingival plaque samples. Additionally, a positive correlation was found between the presence of S. mutans and various periodontal parameters, indicating its significant association with the severity of periodontal disease (Sneha et al., Assessment of Streptococcus mutans in healthy versus gingivitis and chronic periodontitis, Contemporary Clinical Dentistry (2016), 7(4): 529-534).

[0079] Advantageously, the oral care composition as described above has been demonstrated to specifically suppress the growth of S. mutans which has been associated with non-pathologic halitosis or bad breath. Therefore, the composition according to the invention may be used to prevent halitosis or bad breath.

[0080] Halitosis, commonly known as bad breath, is a prevalent issue affecting a significant portion of the general population. The causes of bad breath are often multifactorial, and chronic sufferers may experience considerable psychological distress as a result. Bad breath manifests as distinctly unpleasant odours that are exhaled during breathing. It is estimated that halitosis is the third most common reason people seek dental care, following tooth decay and periodontal disease.

[0081] A study aimed to investigate the correlation between halitosis and the presence of S. mutans in the saliva of patients. It was confirmed that S. mutans is among the bacterial agents initiating biofilm formation on the tooth surface, which subsequently attracts other bacteria, leading to dental plaque formation. Notably, some of these secondary bacteria, such as Fusobacterium, Porphyromonas, and Prevotella, are significant contributors to halitosis (Ghapanchi et al., Lack of Association between Halitosis and the Presence of Streptococcus mutans in Saliva (2015), British Journal of Medicine & Medical Research 10(3): 1-7, 2015). Thus, the disruption of biofilms by antibacterial activity against S. mutans has at least has an indirect mitigating and preventive effect on halitosis.

[0082] The invention will now be described in more detail hereinafter with references to the examples. Further aspects of the present invention are disclosed in the accompanying claims. Brief Description of the Figures

[0083] FIG 1 : Percentage of Streptococcus mutans in 72h biofilms in relation to the absolute bacterial count grown in the presence of the indicated essential oils or components thereof. Vertical blue lines indicate different AAA-models. The number of replicates is N=4, with the exception of maltol and ethylmaltol, which have a replicate number of N=3. Error bars indicate the mean ± standard deviation.

[0084] FIG 2: Total CFU bacterial counts per biofilm in 72h biofilms in relation to the absolute bacterial count grown in the presence of the indicated essential oils or components thereof. Vertical blue lines indicate different AAA-models. The number of replicates is N=4, with the exception of maltol, which has a replicate number of N=3. Error bars indicate the mean ± standard deviation.

[0085] FIG 3: Total CFU Streptococcus mutans counts per biofilm in 72h biofilms in relation to the absolute bacterial count grown in the presence of the indicated essential oils or components thereof. Vertical blue lines indicate different AAA-models. The number of replicates is N=4, with the exception of maltol and ethylmaltol, which have a replicate number of N=3. Error bars indicate the mean ± standard deviation.

[0086] FIG 4: Lactic acid production of 72h biofilms grown in the presence of the indicated essential oils or components thereof. Vertical blue lines indicate different AAA- models. The number of replicates is N=4. Error bars indicate the mean ± standard deviation.

[0087] Examples

[0088] Example 1: Biofilm formation protocol

[0089] The Amsterdam Active Attachment (AAA) model was employed for this experiment. This model comprises a stainless steel lid designed to fit standard 24-well plates. The lid is equipped with 24 clamps to secure the substratum on which biofilms will develop. For this study, glass discs with a diameter of 12 mm were used as the substratum. A total of three lids were prepared, each equipped with glass discs.

[0090] Saliva was collected from a single donor who abstained from tooth brushing for 24 hours and refrained from eating or drinking for 2 hours before collection. The collected saliva was diluted 1 :1 with 60% glycerol, aliquoted, and stored at -80°C until use.

[0091] A freezer stock of Streptococcus mutans C180-2 was thawed and diluted 1 :100 in Brain Heart Infusion (BHI) broth (100 pl stock + 10 ml BHI) and incubated overnight at 37°C. The optical density at 600 nm (OD600) was measured the following morning to determine the culture concentration. The required volume of the overnight culture to achieve an OD of 0.8 in 5 ml McBain medium (buffered with PIPES to pH 7) was calculated. The overnight culture was centrifuged, the supernatant discarded, and the pellet resuspended in 5 ml McBain medium.

[0092] The inoculum was prepared in 20 ml batches, consisting of 20 ml McBain medium with PIPES, 500 pl unfiltered human saliva (from freezer stock), 400 pl S. mutans C180-2 (OD 0.8), and 200 pl sterile 20% sucrose.

[0093] Biofilm formation was initiated by adding 1.5 ml of inoculum per well across the three AAA models. Models 1 and 2 were processed concurrently, while Model 3 was processed separately. After 8 hours, the lids were transferred to new 24-well plates containing buffered McBain medium with additives. Each group consisted of 4 wells, requiring 6 ml of medium (6.3 ml prepared to ensure adequacy). To 6.3 ml McBain medium, 63 pl of the test compound was added. Each model included a control group (water added to McBain medium) and a 1% DMSO carrier control group (63 pl DMSO in McBain medium). Active substances were added in the same ratio, with 63 pl of the active compound added to 6.3 ml of McBain medium. Additionally, 63 pl of 20% sucrose was added to each tube.

[0094] The lids were transferred to fresh 24-well plates containing buffered McBain medium with 0.2% sucrose and the active substances at t=8, 24, 32, 48, and 56 hours.

[0095] Example 2: Lactic Acid Production Assay

[0096] After 72 hours, lactic acid production was assessed using a standard acid production assay in the absence of the test substances. The lids with biofilms were washed in two separate 24-well plates containing CPW (Citrate Phosphate Buffered Water), then transferred to plates with buffered peptone water (BPW) supplemented with 0.2% sucrose. Biofilms were incubated anaerobically for 3 hours, and lactic acid production was measured enzymatically.

[0097] Example 3: Quantification of Biofilms

[0098] Glass discs with biofilms were removed from the lids, transferred to containers with 2 ml CPW, and sonicated to disperse the biofilms. The dispersed biofilms were serially diluted and plated on blood agar plates to determine total Colony Forming Units (CFU). S. mutans counts were determined by plating on selective media.

[0099] The concentration of the test substances was set at twice the Minimum Inhibitory Concentration (2xMIC), which had been determined in preliminary studies.

[0100] Analysis of Colony Forming Unit (CFU) counts from dispersed biofilms indicated that most substances significantly reduced total CFU counts compared to the control and 1% DMSO groups within the same AAA model, shown in FIG 2. However, 0.64% Ethylmaltol and 1.28% Maltol did not exhibit any reduction in total CFU counts. Notably, 10% Neroli oil demonstrated a substantial reduction in total CFU counts, an effect that was visually apparent upon removal of the glass discs from the AAA model, as these biofilms appeared notably thinner. Reductions observed for other substances generally remained within a 1 log reduction.

[0101] Data were analyzed using the software SPSS, version 23. A one-way ANOVA followed by Tukey’s post-hoc test was conducted to compare the means across different treatment groups. An alpha level of 0.05 was used to determine statistical significance.

[0102] The presence of Streptococcus mutans was more significantly impacted by the test substances, with several exhibiting more than a 1 log reduction in CFU counts. Specifically, 1.28% 6-Bisabolol, 1.28% Amyris oil, 1.28% Cabreuva oil, and 10% Neroli oil showed the highest reductions in S. mutans counts. Data in FIG 1 illustrate that all test substances decreased the relative abundance of S. mutans in the biofilms, except for 10% Neroli oil.

[0103] The ability of dental plaque to produce lactic acid was inhibited by several test substances, including 1.28% 6-Bisabolol, 10% Neroli oil, 0.64% Elemol, and 1.28% Amyris oil. Particularly, 6-Bisabolol achieved more than a 50% reduction in lactic acid formation. Interestingly, the reduction in lactic acid production by Elemol was not accompanied by a significant decrease in S. mutans counts, suggesting that Elemol might inhibit other lactic acid-producing bacteria within the biofilm.

Claims

Claims1. Oral hygiene composition comprising at least one essential oil and / or essential oil component(s), wherein the total amount of the at least one essential oil and / or the at least one essential oil component present in the oral hygiene composition is sufficient to achieve an antibacterial effect against Streptococcus mutans, wherein the at least one essential oil and / or the at least one essential oil component is selected from the group consisting of amyris oil, cabreuva oil, paradol, bisabolol and farnesol, wherein, if respectively present, the concentration ofamyris oil is 30 to 200 ppm, preferably 50 to 150 ppm, more preferably 64 to 128 ppm,and / orcabreuva oil is 30 to 200 ppm, preferably 50 to 150 ppm, more preferably 64 to 128 ppm,and / orparadol is 30 to 200 ppm, preferably 50 to 150 ppm, more preferably 64 to 128 ppm,and / orbisabolol is 30 to 200 ppm, preferably 50 to 150 ppm, more preferably 64 to 128 ppm,and / orfarnesol is 5 to 100 ppm, preferably 10 to 50 ppm, more preferably 16 to 32 ppm,in each case based on the total amount of the composition.

2. Oral hygiene composition according to claim 1, wherein the composition is an oral care product selected from the group consisting of mouthwash, dental gel, toothpaste, tooth cream, toothpaste powder, oral spray, lozenge and chewing gum.

3. Oral hygiene composition according to claim 1 or 2, comprising at least one substance selected from the group consisting of carriers, binders, abrasives, detergents, dyes, polishes, surfactants, humectants, thickening agents, sweeteners, aroma, aroma substances, flavourings, taste correcting agents, cooling agents, stabilizers, fluorine source, whitening agents, ethereal oils, emulsifiers, astringents and toning dry extracts, caries inhibiting additives and flavour co rre eta nts.

4. Oral hygiene composition according to any one of claims 1 to 3, comprising one or more essential oil(s) wherein the at least one essential oil is amyris oil, preferably present in 30 to 200 ppm, preferably 50 to 150 ppm, more preferably 64 to 128 ppm, based on the total amount of the composition.

5. Oral hygiene composition according to any one of claims 1 to 3, comprising one or more essential oil component(s), wherein the at least one essential oil component is bisabolol, preferably present in 30 to 200 ppm, preferably 50 to 150 ppm, more preferably 64 to 128 ppm, based on the total amount of the composition.

6. Use of the oral hygiene composition according to any one of claims 1 to 5 to achieve an antibacterial effect against Streptococcus mutans.

7. Use of the oral hygiene composition according to any one of claims 1 to 5 to decrease lactic acid concentration in the oral cavity.

8. Use of the oral hygiene composition according to any one claims 1 to 5 to decrease lactic acid concentration in the oral cavity, wherein the composition additionally comprises elemol, or use of elemol in an oral hygiene composition for decreasing lactic acid concentration in the oral cavity, preferably wherein elemol is present in a concentration of 10 to 100 ppm, preferably 20 to 80 ppm, more preferably 32 to 64 ppm, in each case based on the total amount of the composition.

9. Method for increasing oral hygiene, the method comprising:(i) applying an effective amount of the oral hygiene composition according to any one of claims 1 to 5 to the oral cavity; and(ii) allowing the composition to contact an oral surface for a period sufficient to exert an antibacterial effect against Streptococcus mutans.

10. Method according to claim 9, wherein the application of step (i) is brushing, rinsing, spraying, sucking and / or chewing.

11. Oral hygiene composition according to any one of claims 1 to 5 for use in a method of preventing, mitigating and / or treating a dental plaque-associated disease.

12. Oral hygiene composition for use in a method according to claim 11, wherein the dental plaque-associated disease is selected from the group of dental caries, tooth abscesses and tooth loss.

13. Oral hygiene composition for use in a method of mitigating and / or preventing a dental plague-associated condition, wherein the dental plaque-associated condition is selected from the group of gingivitis, periodontitis, gum recession and halitosis.

Images