BACKGROUND ART Human teeth are a kind of continuous beam. When man chews some foods withelastic movement, a space between teeth is widened, thereby the space between teeth is filled with food particles and a dental root is stressed. As mentioned above, food particles in the space between teeth and plaques generated from food not only provide suitable condition for growth of caries-causing microorganisms in oral cavity and various anaerobic microorganisms causing halitosis, but also cause halitosis and periodontal diseases.

To remove food between teeth, a toothpick or a toothbrush is commonly used.

However, use of a toothpick may damage the gums or the dental root and cause to bleed.

Moreover, use of a toothbrush could not remove the food particles between teeth and the plaques completely. To solve these problems, a dental floss is recommended to use.

In case of using a dental floss, food particles between teeth may be removed, but caries-causing microorganisms between teeth and various anaerobic microorganisms causing halitosis may not removed easily.

Generally, caries and periodontal disease are caused in the following ways. In case of the caries, protein among the saliva in the mouth is absorbed on the surface of

dentine and cement to form a film, on which pathogens such as Streptococcus or Actinomyces grow up to create plaque. As time goes, calcium and phosphorous among the saliva are absorbed onto the plaque to form tartar and at the same time the organic acid secreted by those pathogens decalcifies to create enamel and dentine.

On the other hand, the periodontal disease may bring the tooth to be lost due to gingivitis, bleeding, formation of periodontal pocket or breakage of alveolar bone. In aspect of the generation of such periodontal disease, at first some plaque moves toward root apex and at the same time anaerobic gram-negative bacteria such as Porphyromonas and Actinobacillus grow in gingival sulcus, so these bacteria, bacterial constituent components and bacterial products are penetrated into gingival connective tissue through epithelium of the gingival sulcus to form periodontal pocket. As a result of metabolism of the bacterial, there are secreted toxins harmful for cells such as poisonous hydrogen sulfide, ammonia and poisonous amine in the periodontal tissue.

In addition, various kinds of Cytokine such as activated oxygen, nitrogen oxide, Prostaglandins, Leukotriens, Histamine, Interleuckins and Tumour necrosis factor a secreted out of cells due to various actions of stimulated humoral and cellular immune system generated by stimulating biological immune system cause gingival inflammation, and enzyme such as Collagenase secreted from bacteria and leukocytes dissolve Collagen which is a stroma of the periodontal tissue, thereby causing involution of the gum, which brings periodontal disease when left as it is.

It is reported that xanthorrhizol, as a natural antimicrobial substance, contained in extracts extracted from Curcuma xanthorrhiza shows excellent antimicrobial activity against oral microorganisms (see KR 2000-0000256,2000-0000342, 2000-0006939 and

2000-0073295). However, it has not been reported and proven yet that the aforementioned antimicrobial substance applies to a dental floss, which is effective in preventing caries and halitosis as well as cleaning in oral cavity.

DISCLOSURE OF INVENTION The present invention is designed to solve the problems of the prior art, and therefore an object of the invention is to provide an antimicrobial dental floss for cleaning teeth, which can not only remove food particles and dental plaques between teeth like a conventional dental floss, but also prevent and relieve caries and periodontal disease and eliminate halitosis.

In order to accomplish the above object, an antimicrobial dental floss for cleaning teeth of the present invention contains xanthorrhizol as an effective component.

In the antimicrobial dental floss for cleaning teeth of the present invention, the 0. 1-10wt% of the xanthorrhizol may be included in the form of mixture with wax.

Hereinafter, a dental floss according to the present invention will be described in detail.

The inventors of the present invention revealed that when xanthorrhizol-containg extract from Curcuma xanthorrhiza was applied to a dental floss, the dental floss could not only remove food particles and dental plaques between teeth like a conventional dental floss, but also prevent and relieve caries and periodontal disease and eliminate halitosis, and then completed the present invention.

Curcuma Xanthorrhiza belongs to the ginger family, known as turmeric

produced in Jaba, one of the traditional medicinal plants in Indonesia, and it is known to have various physiological activities such as triglyceride decreasing action, antitumor action, serum cholesterol decreasing action, and so on. In the present invention, xanthorrhizol may be extracted from the Curcuma xanthorrhiza (see, KR 2000-0073295). Since xanthorrhizol has excellent antimicrobial activity against bacteria in oral cavity such as Streptococcus mutans, Streptococcus sobrinus, Porphyromonas gingivalis, and so on, it can be used effectively for prevention and treatment of caries and periodontal disease in a form of oral cleanser etc. To obtain xanthorrhizol-containg extract from Curcuma Xanthorrhiza. , various ways are already known in the art. Supercritical fluid extracting, microwave extracting and supersonic wave extracting may be used in addition to the general organic solvent extracting (see WO 88/05304). In addition, the traditional expression or hot water extracting may be used to obtain oil constituents. To explain the organic solvent extracting as an example, Curcuma Xanthorrhiza extracts is manufactured using the following processes: a) drying and grinding purified Curcuma Xanthorrhiza, b) conducting extraction by putting an extracting solvent into the pulverized Curcuma Xanthorrhiza, c) filtering the extracted stock solution, d) condensing the filtered extracted stock solution, and e) freeze-drying the condensed stock solution into dried powder.

Preferably, the antimicrobial dental floss for cleaning teeth of the present invention may be manufactured by passing a fiber for dental floss through a solution of 0. 1-10wt% xanthorrhizol dissolved in wax. When the content of xanthorrhizol is less than 0.1 wt%, antimicrobial effect on oral microorganisms may not be expected When the content of xanthorrhizol is more than 10 wt%, its compatibility with wax may

be reduced. To the wax, flavoring agent and another antimicrobial component known to those skilled in the art may be added.

BEST MODES FOR CARRYING OUT THE INVENTION Hereinafter, the present invention is described in more detail with several examples. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Example for extraction The extract containing xanthorrhizol used in the present invention was prepared as follows: medicinal herbs of Curcuma xanthorrhiza were dried in the shade, minced, and then pulverized. To the resulting powder 50g, 95% ethanol 500mL was added and subsequently extracted by deposition for 3 days. The resulting extract was filtered using Whatman N0. 1 followed by concentrating under reduced pressure to obtain the extract containing xanthorrhizol.

Example 1 Mycrstalline wax was added to a mixture of the extract containing xanthorrhizol obtained by aforementioned example 0.38g, mint flavor 5g and menthol 5g to obtain 100g of the composition, and then heated to 80 °C to become completely dissolved

(solution). Nylon fiber for a dental floss was passed through the resulting wax solution to obtain a dental floss.

Examples 2-4 Dental flosses were manufactured in the same manner as aforementioned Example 1, except for contents of xanthorrhizol as listed Table 1.

Comparative Example 1 Without adding xanthorrhizol, a dental floss was manufactured in the same manner as aforementioned Example 1.

Table 1 (wt %) Comparative Examples Example 1 2 3 4 Xanthorrhizol (pure) 0. 1 1. 0 5. 0 10 0 Flavoring agent 5. 0 5. 0 5. 0 5. 0 1. 0 menthol 5. 0 5. 0 5. 0 5. 0 5. 0 Wax Balance (to 100)

Tests for antimicrobial effects For the dental flosses obtained by the Examples 1-4 and Comparative Example 1, their antimicrobial effects were tested as follows. In the tests, 4 kinds of pathogens were used, i. e. dental caries-causing pathogen such as Streptococcus mutans

ATCC25175, and oral anaerobic pathogens such as Porphyromomas gingivalis ATCC 33277, Prevotella intermedia ATCC 25611 and Fusobacterium nucleatum ATCC 25586.

The antimicrobial activity tests were conducted after subculturing these pathogens and then preculturing them for 24 hours 3 times. Equal amount of each pathogen culture fluid was smeared in suitable agar medium followed by adding the equal amount of the dental floss obtained by the above Examples and Comparative Example respectively. After cultivating them for 18 hrs, the growth of the pathogens was observed and then the results were summarized in Table 2. The antimicrobial activity of the dental floss was determined by degree of the growth around the dental floss, which was decided as effectiveness when the growth inhibition zone around the dental floss was 1 mm or more.

Table 2

S. mutans P. gingivalis P. intermedia F. nucleatum loo oo 2 0 0 0 0 Examples 3 0 0 0 0 4 0 0 0 0 Comparative Example x x x x 1 As shown in Table 2, dental flosses containing xanthorrhizol were proven to have excellent antimicrobial effects on all pathogens such as Streptococus mutans, Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and so on.

INDUSTRIAL APPLICABILITY As detailed in the above, the antimicrobial dental floss for cleaning teeth according to the present invention has antimicrobial activity against causative microorganisms of caries and periodontal disease in oral cavity. Therefore, the antimicrobial dental floss for cleaning teeth of the present invention can not only remove food particles and dental plaques present in teeth like a conventional dental floss, but also prevent and relieves caries and periodontal disease such as gingivitis and eliminate halitosis very effectively.