Abstract:
An anticariogenic or antiperiodontitic agent containing, as an active component, adenosine or its derivatives having an antibacterial activity against Streptococcus mutans or Bacteroides gingivalis. This anticariogenic or antiperiodontitic agent has strong inhibitory effects on the growth of Streptococcus mutans causing dental caries and Bacteroides gingivalis causing periodontitis and has neither influence on intestinal microflora nor any side-effects when orally administered.

Description:
This application is a continuation of application Ser. No. 824,560, filed Jan. 23, 1986, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to anticariogenic or antiperiodontitic products such as beverages and foods which contain adenosine and its derivatives and which have an anticariogenic or antiperiodontitic activity. 
     2. Description of the Related Art 
     Several kinds of antibiotics and other substances acting in a manner similar to anti-bacterial substances against Streptococcus mutans and Bacteroides gingivalis, which are major pathogens of dental caries and periodontitis, respectively, have been proposed. However, their side-effects, for example, the influence of these substances on intestinal microflora, are not yet fully understood, and accordingly, these substances are not used in practice since there is no proof that they are safe for daily usage. 
     SUMMARY OF THE INVENTION 
     Accordingly, the objects of the present invention are to eliminate the above-mentioned possible side-effects of the prior art and to provide an anticariogenic or antiperiodontitic agent or composition having strong inhibitory effects on the growth of Streptococcus mutans causing dental caries and Bacteroides gingivalis causing periodontitis and having no influence on intestinal microflora when orally administered. 
     Other objects and advantages of the present invention will be apparent from the following description. 
     In accordance with the present invention, there is provided an anticariogenic or antiperiodontitic agent or composition containing, as an active component, adenosine and its derivatives having antibacterial activity against Streptococcus mutans or Bacteroides gingivalis. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present inventors have found that adenosine and its derivatives have strong inhibitory effects on the growth of S. mutans causing dental caries and B. gingivalis causing periodontitis, but show no toxicity in animal experiments and no influence on intestinal microflora when orally administered. 
     The anti-bacterial products according to the present invention, the physiological characteristics thereof, the forms in practical use, and the like, will now be described in detail. 
     Antibacterial Product 
     Effective constituents of antibacterial products according to the present invention are adenosine and its derivatives. A particularly suitable example of such compounds is shown by the following chemical formula. ##STR1## wherein R 1  is --H, --CH 3 , or ##STR2## R 2  is --H, --OH, --Cl, --SCH 3 , or --SCH 2  CH(CH 3 ) 2 , R 3  is --CH 2  CH 2  CH(NH 2 )COOH or --H, and R 4  is --H or --Cl. 
     Typical examples of such compounds are vitamin L 2  (i.e., methylthioadenosine), 5&#39;-deoxy-5&#39;-chloroadenosine, N-6-methyladenosine, N-6-benzyladenosine, 2-chloroadenosine, 5&#39;-deoxyisobutylthioadenosine, adenosine, and spongoadenosine (adenosine-9β-D-arabinofuranoside) which is an adenosine stereoisomer, and the like. Furthermore, S-adenosylmethionine is an example of a compound which can be easily decomposed to give vitamin L 2  and having antibacterial activity. These compounds are known and are commercially available. Furthermore, these compounds can be prepared in any conventional manner. For example, vitamin L 2  (methylthioadenosine (MTA)) is chemically synthesized as follows: 
     
         Adenosine+SOCl.sub.2 →5&#39;-deoxy-5&#39;-chloroadenosine 5&#39;-deoxy-5&#39;-chloroadenosine+NaSCH.sub.3 →MTA+NaCl 
    
     These reactions are used for the preparation of vitamin L 2  (MTA) and many of its analogs (Schlenk, F., Methylthioadenosine In: Advances in Enzymology 54: 195-265 (1983)). 
     Physiological Characteristics 
     1. Antibacterial activity 
     As shown in the Examples below, the anticariogenic and antiperiodontitic products of the present invention effectively depress or inhibit the growth of S. mutans which cause dental caries and B. gingivalis which causes periodontitis. 
     2. Acute toxicity 
     As shown in the Examples below, an LD 50  value of the anticariogenic and antiperiodontitic products of the present invention is more than 1 g/kg body weight, orally administered to mice, and is substantially nontoxic on oral administration. 
     Forms in practical use 
     The anticariogenic and antiperiodontitic products of the present invention can be practically used in the form of, for example, tooth-paste, gargles, troches, chewing gum, and the like, and in the form of various kinds of anticariogenically and antiperiodontitically depressive and preventive foods and beverages added with the anticariogenic and antiperiodontitic products. The amount used in practical use is about 0.001% to 1% (w/w), based on the total weight of the composition. 
     Any conventional ingredients can be formulated into the present compositions. For example, in the case of tooth-pastes, ingredients such as secondary calcium phosphate (30-50%, w/w), glycerin (15.20%, w/w), carrageenan (0.5-20%, w/w), sodium lauryl sulfate as detergent (0.8-1.5%, w/w) and flavor (0.5.1.5%, w/w) can be added; in the case of gargles, ethanol (15.20%, w/w), saccharin (0.1-0.5%, w/w), sodium acyltaurate (0.2-0.6%, w/w), flavor (0.5-1.5%, w/w) and others can be added; and gum base (18-25%, w/w), calcium carbonate (1-5%, w/w), lactose (65-75%, w/w) and others can be added in the case of chewing gums. These additives are shown below in Examples in practical use. 
    
    
     EXAMPLES 
     The present invention will now be further shown by, but is no means limited to, the following Examples. 
     EXAMPLE 1 
     Antibacterial activity of vitamin L 2  (methylthioadenosine) 
     A sample of vitamin L 2  (methylthioadenosine) (Sigma Chemical Company) having the chemical formula shown below was dissolved in water, ##STR3## the pH was adjusted to 7, and sterilization was carried out by autoclaving at 121° C. for 15 min or by filtration with membrane filters, to form a sterile solution. This sample solution mentioned above was added into a sterile basal medium (refer to Table 1) together with sterile distilled water to adjust the concentration of the sample. To this medium, S. mutans causing dental caries, Actinomyces naeslundii and A. viscosus causing dental caries and periondontitis, and B. gingivalis and Fusobacterium nucleatum causing periodontitis, each bacterium being isolated from a human oral cavity, were repectively inoculated. After incubation at 37° C. for 24 hrs, the MIC (minimal growth-inhibitory concentration: μg/ml) against each bacterium was determined. As a control, a 0.85% NaCl solution was used instead of the sample solution of vitamin L 2 . Furthermore, the effect of vitamin L 2  on intestinal bacteria such as S. faecium, S. faecalis, Bifidobacterium bifidum, Lactobacillus acidophilus, and L. fermentum, isolated from the feces of healthy humans, was also determined by the same procedures. The results are shown in Table 1. 
     
                       TABLE 1______________________________________  MIC (μg/ml)           Basal medium______________________________________S. mutans    63         Todd-Hewitt broth (Difco               Laboratories)A. naeslundii    32         Brain heart infusion broth               (Difco Laboratories)A. viscosus    63         Brain heart infusion brothB. gingivalis     125       GAM broth (Nissui Pharmaceutical               Co., Ltd.)F. nucleatum     500       GAM brothS. faecium    &gt;1000      Todd-Hewitt brothS. faecalis    &gt;1000      Todd-Hewitt brothBif. bifidum    &gt;1000      GAM brothL. acidophilus    &gt;1000      Rogosa broth *1L. fermentum    1000       Rogosa broth______________________________________ *1: Composition of Rogosa broth medium Trypticase 10 g Yeast extract 5 g Tryptose 3 g K.sub.2 HPO.sub.4 3 g KH.sub.2 PO.sub.4 3 g Triammonium citrate 2 g Tween 80 *3 1 g Glucose 20 g Cysteine hydrochloride 0.2 g Salt solution *2 5 ml Distilled water to 1 liter (pH 7, heat sterilization at 121° C. for 15 minutes) *2: MgSO.sub.4.7H.sub.2 O 11.5 g FeSO.sub.4.7H.sub.2 O 0.68 g MnSO.sub.4 .2H.sub.2 O 2.4 g Distilled water 100 ml *3: Polyoxyethylene (20) sorbitan monooleate available from Atlas Powder Co. 
    
     (Efthymiou, C., and Hansen, P. A. An antigenic analysis of Lactobacillus acidophilus. J. Infect. Dis. 110: 258-267 (1962)) 
     EXAMPLE 2 
     Antibacterial activity of each adenosine derivative 
     The MIC (μg/ml) of seven kinds of adenosine derivatives (Sigma Chemical Company), having the chemical formulas as shown in Table 2, against S. mutans and B. gingivalis was determined by the same procedures as in Example 1. The results are shown in Table 3. 
     
                                           TABLE 2__________________________________________________________________________ ##STR4##Materials        R.sub.1   R.sub.2   R.sub.3                                   R.sub.4                                       R.sub.5__________________________________________________________________________(1) 5&#39;-deoxy-5&#39;-chloroadenosine            H         Cl        H  H   OH(2) N-6 methyladenosine            CH.sub.3  OH        &#34;  &#34;   &#34;(3) N-6 benzyladenosine             ##STR5## &#34;         &#34;  &#34;   &#34;(4) 2-chloroadenosine            H         &#34;         Cl &#34;   &#34;(5) (5&#39;-deoxy) isobutylthioadenosine            &#34;         SCH.sub.2 CH(CH.sub.3).sub.2                                H  &#34;   &#34;(6) adenosine    &#34;         OH        &#34;  &#34;   &#34;(7) spongoadenosine            &#34;         &#34;         &#34;  OH  H(8) 5&#39;-deoxyadenosine            &#34;         H         &#34;  H   OH__________________________________________________________________________ 
    
     
                       TABLE 3______________________________________         BacteriaMaterials No.   S. mutans                    B. gingivalis______________________________________(1)              250     125(2)             1000     250(3)             1000     250(4)             1000     250(5)             1500     250(6)             1000     No inhibition(7)             1500      16(8)             1000     125______________________________________ 
    
     EXAMPLE 3 
     Acute toxicity 
     The above adenosine derivatives were orally administered to ICR mice (6 week-old, male, average body weight of 31.0±0.6 g, 10 mice per group) in the form of a 0.5 ml saline solution having the equivalent amounts of the derivatives of 1, 10, 100 mg/mouse. The sanatobiological observation of the mice was carried out for 14 days. 
     The LD 50  values (mg/kg body weight) calculated according to the Behrens-Karber method were more than 1000 mg/kg body weight, but were substantially nontoxic in the case of daily oral administration. 
     
         ______________________________________Examples in practical use1. Tooth-paste       Wt. %______________________________________Secondary calcium phosphate                30-50Glycerin             15-20Carrageenan          0.5-20Sodium lauryl sulfate                0.8-1.5p-Oxybutyl benzoate  0.001-0.005Flavor               0.5-1.5Antibacterial products of                0.01-5the present invention                100______________________________________2. Gargles______________________________________Ethanol (90%)        15-20Saccharin            0.1-0.5Sodium acyltaurate   0.2-0.6Gelatin              0.1-0.6Flavor               0.5-1.5Chlorohexidine       0.002-0.007Antibacterial products of                0.01-5the present inventionWater                Remainder                100______________________________________3. Chewing gum______________________________________Gum base             18-25CaCO.sub.3           1-5Saccharin            0.05-0.2Lactose              65-75Antibacterial products of                0.001-0.5the present invention                100______________________________________ 
    
     4. Anticariogenic foods and beverages 
     The antibacterial products of the present invention can be used for anticariogenic or antiperiodontitic foods and beverages by the addition of 0.001% to 1% by weight (dry weight) of the products into bread, cookies, candies, yogurt, fruit juice, tea, coffee, etc., and other general foods and beverages.