WO2007012080A2

WO2007012080A2 - Oral care composition

Info

Publication number: WO2007012080A2
Application number: PCT/US2006/028482
Authority: WO
Inventors: David Beddie; Natalie Isles
Original assignee: John I. Haas, Inc.
Priority date: 2005-07-20
Filing date: 2006-07-20
Publication date: 2007-01-25
Also published as: WO2007012080A3; GB0514943D0; AU2006269866A1; KR20080043779A; CA2615629A1; EP1919438A2; JP2009514789A

Abstract

The invention generally relates to oral care compositions containing natural tree resins or acids or derivatives thereof, which inhibit undesirable bacteria that are known to cause dental caries, gingivitis and other periodontal diseases.

Description

ORAL CARE COMPOSITION

CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation of and claims priority from United Kingdom

Application No. GB0514943.0, which was filed on July 20, 2005, the entire disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION Periodontal diseases, gingivitis and dental caries are major public health diseases world-wide. These diseases can be inhibited to a certain extent by frequent brushing of the teeth, although the use of antibacterial agents gives better results. Chemical antibacterial agents such as chlorhexidine, triclosan and benzalkonium chloride have traditionally been used. Additionally natural products have shown activity against bacteria, which cause dental caries.

SUMMARY OF THE INVENTION

An object of the invention is to provide oral care products that inhibit the microorganisms that cause dental caries and periodontal disease using natural resins.

DETAELED DESCRIPTION OF THE INVENTION

The invention generally provides oral care compositions that inhibit the growth, survival, or proliferation of a microorganism associated with dental caries and periodontal disease that comprise a natural resin. This invention is based, at least in part, on the finding that natural tree resins control the growth of common oral microorganisms such as Actinomyces viscosus and Streptococcus mutans both gram- positive organisms. Additionally, these natural resins are active against the gram- negative bacteria Fusobacterium nucleatum. This broad spectrum of activity gives additional benefits over other natural products used in oral care products.

Accordingly, the present invention provides the use of tree resins or extracts or derivatives thereof to prepare an oral care composition having antibacterial activity against bacteria implicated in dental caries, gingivitis and other periodontal diseases. The present invention also provides an oral care composition having antibacterial activity against bacteria implicated in dental caries, gingivitis and other periodontal diseases, comprising a tree resin or derivative thereof and an orally acceptable carrier. Such oral care compositions are advantageously combined with hop resins, hop extracts, hop acids or hop acid derivatives. US Patent No. 3,932,603 teaches that hop extract resins such as lupulone and humulone, from the hop plant humulus lupulus, are effective against cariogenic streptococci. US Patent No. 5,316,760 describes a mouth care product that contains a combination of Urtica dioica and an extract of Juniperus communis.

Hop acids include alpha and beta acids. In particular, oral care compositions comprise alpha acids or reduced isoalpha acids (e.g., rhoisoalpha acids, tetrahydroisoalpha acids or hexahydroisoalpha acids isoalpha acids) or beta acids (e.g., hexahydrobeta acids and tetrahydrobeta acids). In one embodiment, the hop acids are beta acids selected from the group consisting of lupulone, colupulone, adlupulone and derivatives thereof. In another embodiment, the beta acids are hexahydrobeta acids or tetrahydrobeta acids. In various embodiments, the concentration of hop acids present in the oral care composition is between about 0.001 and 0.1% (e.g., 001, 0.0025, 0.005, 0.01, 0.025, 0.05, 0.1%). In another embodiment the concentration of hop acid is between about 1% and 99% (e.g., 1%, 2.5%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 50%, 75%, 85%, or 95%).

Hop acid derivatives are compounds that are chemically derived (either through natural biosynthetic processes (e.g., living organism metabolism (e.g., mammal, plant, bacteria)) or synthetic processes using human intervention (e.g., chemical synthesis)) from hop acids. Alpha acid derivatives (e.g., isoalpha acids, rhoisoalpha acids, tetrahydroisoalpha acids, and hexahydroisoalpha acids) are compounds derived from hop alpha acids.

As used herein, the term "rhoisoalpha acids" refers to alpha acids isolated from hops plant product and which subsequently have been isomerized and reduced, using sodium borohydride, including cis and trans forms. Examples of rhoisoalpha acids include, but are not limited to, rhoisohumulone, rhoisocohumulone, and rhoadhumulone.

As used herein, the term "tetrahydroisoalpha acids" refers to a class of reduced isoalpha acids produced by hydrogenation of isoalpha acids. Examples of tetrahydroisoalpha acids include, but are not limited to, tetrahydroisohumulone, tetrahydroisocohumulone and tetrahydroadhumulone.

As used herein, the term "hexahydroisoalpha acids" refers to a class of reduced isoalpha acids, produced by hydrogenation of isoalpha acids and sodium borohydride reduction of the resulting tetrahydroisoalpha acids. Examples of hexahydroisoalpha acids include, but are not limited to, hexahydroisohumulone, hexahydroisocohumulone and hexahydroadhumulone.

As used herein, the term "beta acids" refers to compounds that can be isolated from hops plant products, including but not limited to, lupulone, adlupulone, colupulone, tetrahydrolupulone, tetrahydroadlupulone, tetrahydrocolupulone and their derivatives. Exemplary beta acids include, but are not limited to, hexahydrobeta acids and tetrahydrobeta acids.

The term "extract" refers to a concentrated preparation of the essential constituents of a plant (e.g., medicinal plant, hops). Typically, an extract is prepared by drying and powderizing the plant. Optionally, the plant, the dried plant or the powderized plant may be boiled in solution. The extract may be used in liquid form, or it may be mixed with other liquid or solid herbal extracts. Alternatively, the herbal extract may be obtained by further precipitating solid extracts from the liquid form. An extract can be prepared by drying and subsequently cutting or grinding the dried material. The extraction process may then be performed with the help of an appropriate choice of solvent, typically supercritical or liquid carbon dioxide, ethanol/water mixture, methanol, butanol, iso-butanol, acetone, hexane, petroleum ether or other organic solvents by means of maceration, percolation, repercolation, counter-current extraction, turbo-extraction, or by carbon-dioxide hypercritical (temperature/pressure) extraction. The extract may then be further evaporated and thus concentrated to yield by means of air drying, spray drying, vacuum oven drying, fluid-bed drying or freeze-drying, the extract product.

The synthesized compounds can be separated from a reaction mixture and further purified by a method such as column chromatography, high pressure liquid chromatography, or recrystallization. As can be appreciated by the skilled artisan, further methods of synthesizing the compounds herein will be evident to those of ordinary skill in the art. Additionally, the various synthetic steps may be performed in an alternate sequence or order to give the desired compounds. Synthetic chemistry transformations and protecting group methodologies (protection and deprotection) useful in synthesizing the compounds described herein are known in the art and include, for example, those such as described in R. Larock, Comprehensive Organic Transformations, 2nd. Ed., Wiley- VCH Publishers (1999); T. W. Greene and P.G.M. Wuts, Protective Groups in Organic Synthesis, 3rd. Ed., John Wiley and Sons (1999); L. Fieser and M. Fieser, Fieser and Fieser's Reagents for Organic Synthesis, John Wiley and Sons (1999); L. Paquette, ed., Encyclopedia of Reagents for Organic Synthesis, John Wiley and Sons (1995), and subsequent editions thereof and M. Verzele and D. De Keukeleire, Chemistry and Analysis of Hop and Beer Bitter Acids, Elsevier (1991).

An extract can be prepared by drying and subsequently cutting or grinding the dried material. The extraction process may then be performed with the help of an appropriate choice of solvent, typically supercritical or liquid carbon dioxide, ethanol/water mixture, methanol, butanol, iso-butanol, acetone, hexane, petroleum ether or other organic solvents by means of maceration, percolation, repercolation, counter-current extraction, turbo-extraction, or by carbon-dioxide hypercritical (temperature/pressure) extraction. The extract may then be further evaporated and thus concentrated to yield by means of air drying, spray drying, vacuum oven drying, fluid-bed drying or freeze-drying, the extract product. The synthesized compounds can be separated from a reaction mixture and further purified by a method such as column chromatography, high pressure liquid chromatography, or recrystallization. As can be appreciated by the skilled artisan, further methods of synthesizing the compounds herein will be evident to those of ordinary skill in the art. Additionally, the various synthetic steps may be performed in an alternate sequence or order to give the desired compounds. Synthetic chemistry transformations and protecting group methodologies (protection and deprotection) useful in synthesizing the compounds described herein are known in the art and include, for example, those such as described in R. Larock, Comprehensive Organic Transformations, 2nd. Ed., Wiley- VCH Publishers (1999); T. W. Greene and P.G.M. Wuts, Protective Groups in Organic Synthesis, 3rd. Ed., John Wiley and Sons (1999); L. Fieser and M. Fieser, Fieser and Fieser's Reagents for Organic Synthesis, John Wiley and Sons (1999); L. Paquette, ed., Encyclopedia of Reagents for Organic Synthesis, John Wiley and Sons (1995), and subsequent editions thereof and M. Verzele and D. De Keukeleire, Chemistry and Analysis of Hop and Beer Bitter Acids, Elsevier (1991).

The oral care products or compositions of the present invention may include powders, pastes, gums, gels, solutions and the like for rinsing, brushing, washing, chewing or topical application in the oral cavity. The oral care products are formulated by conventional means known to those skilled in the art to ensure that the active ingredient comes in contact with the oral cavity such as teeth and gums as well as any calculus or plaque that may be present.

Toothpastes are generally a slurry of an abrasive, a humectant, a thickening agent, fluoride, surfactants and flavours. Suitable abrasives include silica precipitates, anhydrous dicalcium phosphate, dihydrated dicalcium phosphate, hydrated alumina, calcium carbonate, sodium bicarbonate, sodium metaphosphate, and mixtures thereof. Suitable humectants include sorbitols, polyethylene glycols and glycerine. Suitable thickening agents include cellulose derivatives, silica thickeners, gums such as Xanthan gum, carrageenan, carboxyvinyl polymers etc. Examples of suitable fluoride salts are sodium fluoride, potassium fluoride, sodium hexafluorosilicate and sodium monofluorophosphate. Numerous surfactants may be used, such as sodium dodecylbenzene sulfonate, sodium lauryl sulfate, sodium monosulfated monoglyceride of long chain fatty acids and the like. Conventional flavours may be added to give a pleasant and refreshing taste to the formulation.

Mouth washes or oral rinses are typically a water-alcohol mixture. The alcohol is typically ethanol or iso-propanol. Additionally, humectants, thickening agents, surfactants, colours and flavouring agents may be added to the water-alcohol mixture. Chewable compositions may be formulated using a conventional gum base to prepare an anti-bacterial chewing gum.

To prepare the oral composition, the pine resins can be added in a range of forms such as neat, ground as a fine powder or molten, although it may be preferential to form an aqueous alkaline salt solution of resin acids or as an alcoholic solution. It also may be advantageous to premix the rosin with a surfactant and admix with the other ingredients.

The antimicrobial resin acids should be present in the formulation in an amount sufficient to produce an effective concentration in the mouth and to be able to come in contact with the microbes. Normally this may involve the formation of oral compositions which contain the resin acid at about 0.001% to 0.1% by weight although it may depend on the resin acid used. In other embodiments, the resins are present in an amount effective to kill bacteria ranging from about 1 to 10,000 ppm, from about 5 to 1,000 ppm, or from about 10 to 100 ppm. In various embodiments, the bottom of the range is any integer between 1 and 9,999 ppm and the top of the range is any integer between 2 and 10,000 ppm.

Tree resins useable in this invention include especially pine resins, often called colophonium or pine rosin. In this invention, individual components isolated from pine resins such as abietic acid, palustric acid, levopimaric acid, neoabietic acid, dehydroabietic acid, pimaric acid and isopimaric acid may also be used. Other tree resins include benzoin, myrrh, and pine balsam.

Additionally tree resins can include synthesised tree resin analogues, modified natural resins such as hydrogenation, polymerisation derivatives and synthesised resin derivatives. There is limited data on the anti-bacterial activity of tree resins and derivatives. For instance EP 0465663A1 describes the anti-bacterial activity of abietic acid and tetrahydroabietic acid against bacteria associated with acne. WO 01/88205 describes a method for using natural food compatible resins to produce sugar.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a histogram showing the effect of different concentrations of resin acids on the growth of S. mutans.

Figure 2 is a graph showing the growth of S. mutans with respect of a control sample.

The invention is further illustrated, by way of example only, by the following Examples.

Example 1: Mouth-rinse formulations

A 0.001% rosin mouthrinse formulation was prepared by adding a 0.1% aqueous alkaline solution of Chinese rosin acids (0.2g) to ethanol (5g) and water (14.8g). This gave a clear colourless solution.

Similarly a 0.01% rosin mouthrinse formulation was prepared by adding a 1% aqueous alkaline solution of Chinese rosin acids (0.2g) to ethanol (5g) and water (14.8g) which gave a clear colourless solution.

Further ingredients such as colours and flavours can be added to this formulation. Example 2: Toothpaste formulations

A toothpaste formulation containing 0.001% rosin was prepared by adding a 0.1% aqueous alkaline solution of Chinese rosin acids (0.2g) to a toothpaste formulation (19.8g) containing water, silica, glycerin, titanium dioxide, sodium lauryl sulfate, xanthan gum, sodium fluoride, flavourings.

Similarly, 0.01% and 0.1% rosin toothpaste formulations were prepared. No significant physical differences in the toothpaste formulation were observed.

Example 3: Minimum inhibitory concentration (MIC) assay

Assays were conducted by serially diluting the rosin acids in Brain Heart Infusion broth (Oxoid) and Thioglycolate broth (Merck) for Streptococcus mutans (NCTC10449) and Actinomyces viscosus (NCTC10951) respectively and in brain heart infusion agar for Fusobacterium nucleatum (NCTC10562). The final concentration of rosin acids in the media ranged from 1 ppm to 80 ppm. All the dilution series were conducted in triplicate and in the case of the broth MIC inoculated with approximately 10⁵ freshly cultured (using the same medium) cells per ml of test assay broth. In each assay an inoculated control without any rosin acids was used as a positive control, and un-inoculated media acted as the negative control.

Results and Discussion

The results of the broth MIC assay for S. mutans are shown in Figure 1 of the accompanying drawings and summarized in the text for A. viscosus. As Figure 1 shows rosin acids inhibited the growth of S. mutans to less than 7% to that of the control sample at a concentration of 80 ppm. It can be concluded that growth of S. mutans is strongly correlated (r² = 0.92) to rosin acid concentration, as shown in Figure 2 of the accompanying drawings. Similarily rosin acids inhibited the growth of A. viscosus to less that 8% of the control sample at a concentration of 20 ppm and again the growth is strongly correlated (r² = 0.87) to rosin acid concentration. The results of the agar dilution MIC (results not shown) for F. nucleatum showed that growth was completely inhibited at a concentration of 20 ppm rosin acids. Beta acids at the same concentration and up to 5 times this level had no activity against this Gram negative bacterium.

Other Embodiments From the foregoing description, it will be apparent that variations and modifications may be made to the invention described herein to adopt it to various usages and conditions. Such embodiments are also within the scope of the following claims.

The recitation of a listing of elements in any definition of a variable herein includes definitions of that variable as any single element or combination (or subcombination) of listed elements. The recitation of an embodiment herein includes that embodiment as any single embodiment or in combination with any other embodiments or portions thereof.

AU patents and publications mentioned in this specification are herein incorporated by reference to the same extent as if each independent patent and publication was specifically and individually indicated to be incorporated by reference.

Claims

1. A method of treating or preventing dental caries, gingivitis and other periodontal diseases, the method comprising contacting an oral bacteria with a composition comprising tree resins or extracts or derivatives thereof having antibacterial activity against bacteria implicated in dental caries, gingivitis and other periodontal diseases.

2. The method of claim 1 , wherein the tree resins are rosin or colophonium.

3. The method of claim 1 , wherein the tree resins are rosin derivatives.

4. The method of claim 1 , wherein an antimicrobial agent is present in an amount effective to kill bacteria ranging from 1 to 10,000 ppm.

5. The method of claim 1, wherein the tree resins are used in combination with other antimicrobial agents.

6. The method of claim 1, wherein the other antimicrobial agents are hop resins or hop acids.

7. The method of claim 6, wherein the hop acids are hop alpha acids or hop beta acids.

8. The method of claim 7, wherein the hop alpha acids are selected from the group consisting of isoalpha acids, rhosoalpha acids, tetrahydroisoalpha acids, and hexahydroisoalpha acids.

9. The method of claim 7, wherein the hop beta acids are selected from the group consisting of lupulone, colupulone, adlupulone and derivatives thereof and / or mixtures thereof.

10. The method of claim 1 , wherein the beta acids are hexahydrobeta acids or tetrahydrobeta acids.

11. The method of claim 1 , wherein the oral care composition is a toothpaste.

12. The method of claim 1 , wherein the oral care composition is a mouth wash.

13. The method of claim 1 , wherein the composition is a chewing gum.

14. The oral care composition of claim 1 , wherein the composition is a tooth paste.

15. An oral care composition having antibacterial activity against bacteria implicated in dental caries, gingivitis and other periodontal diseases, comprising a tree resin or extract or derivative thereof and an orally acceptable carrier.

16. The oral care composition of claim 15, wherein the tree resins are rosin or colophonium.

17. The oral care composition of claim 15, wherein an antimicrobial agent is present in an amount effective to kill bacteria ranging from 1 to 10000 ppm.

18. The oral care composition of claim 15, wherein the tree resins are used in combination with other antimicrobial agents.

19. The oral care composition of claim 15, wherein the other antimicrobial agents are hop resins or hop acids.

20. The oral care composition of claim 19, wherein the hop acids are hop alpha acids or hop beta acids.

21. The oral care composition of claim 20, wherein the hop alpha acids are selected from the group consisting of isoalpha acids, rhosoalpha acids, tetrahydroisoalpha acids, and hexahydroisoalpha acids.

22. The oral care composition of claim 20, wherein the hop beta acids are selected from the group consisting of lupulone, colupulone, adlupulone and derivatives thereof and / or mixtures thereof.

23. The oral care composition of claim 22, wherein the beta acids are hexahydrobeta acids or tetrahydrobeta acids.

24. A mouth wash having antibacterial activity against bacteria implicated in dental caries, gingivitis and other periodontal diseases, comprising a tree resin or extract or derivative thereof and a mouth wash base.

25. A chewing gum having antibacterial activity against bacteria implicated in dental caries, gingivitis and other periodontal diseases, comprising a tree resin or extract or derivative thereof and a chewing gum base.

26. A toothpaste having antibacterial activity against bacteria implicated in dental caries, gingivitis and other periodontal diseases, comprising a tree resin or extract or derivative thereof and a tooth paste base.

27. The mouth wash, chewing gum, or toothpaste of claim 25, 26, or 27, further comprising hop resins or hop acids.