The present invention relates to a novel antimicrobial active substance, and more particularly, it relates to an antimicrobial active substance DM0507 having an antimicrobial activity against a broad spectrum of strains and the use thereof.
It is known that microorganisms produce an antimicrobial active substance having such as an antibacterial, antifungal or antiviral activity, and penicillin produced by strains of the genus Penicillium, cephalosporin produced by the genus Cephalosporium, streptomycin, tetracycline, erythromycin produced by the genus Streptomyces and the like have been widely used as antimicrobial active substances.
It is also known that the use of these antimicrobial active substances for many years results in the occurrence of bacteria having resistance to these antimicrobial active substances (resistant bacteria), therefore there has been a demand for a more potent novel antimicrobial active substance.
Accordingly, an object of the present invention is to provide a more potent novel antimicrobial active substance which is derived from a naturally occurring substance and has a broad antimicrobial spectrum.
The present inventors have made extensive studies in order to accomplish the above-mentioned object, and as a result, they found that a substance having an antimicrobial activity against a broad spectrum of strains can be obtained from a culture medium of a special strain of Bacillus subtilis, thus the present invention has been completed. In addition, they found that the above-mentioned substance having an antimicrobial activity can exhibit the antimicrobial activity even if it is added to any of a variety of existing products, thus the present invention has been completed.
That is, the present invention is directed to an antimicrobial active substance DM0507, characterized by obtaining by a production process comprising the following steps (a) to (d):
Further, the present invention is directed to an antimicrobial agent containing the above-mentioned antimicrobial active substance DM0507 as an active ingredient.
Further, the present invention is directed to a food or drink containing the above-mentioned antimicrobial active substance DM0507.
Further, the present invention is directed to a process for producing an antimicrobial active substance DM0507, characterized by comprising the following steps (a) to (d):
The antimicrobial active substance DM0507 of the present invention has an antimicrobial activity against a broad spectrum of strains.
Accordingly, by using the antimicrobial active substance DM0507 of the present invention, a variety of antimicrobial agents, foods, drinks, etc. having an excellent antimicrobial activity can be obtained.
An antimicrobial active substance DM0507 (hereinafter referred to as simply “DM0507”) of the present invention can be obtained by a production process comprising the steps described below:
The Bacillus subtilis to be used in the culture in the step (a) of the above-mentioned production process is not particularly limited as long as it produces DM0507, however, preferred examples include Bacillus subtilis DB9011 strain (FERM BP-3418) and Bacillus subtilis MBI 600 strain (Becker Underwood, Inc. : SUBTILEX (trade name)), and particularly preferred examples include Bacillus subtilis DB9011 strain.
Since the culture of the above-mentioned Bacillus subtilis can be carried out by a standard method, the culture conditions are not particularly limited, however, for example, the conditions in which a shaking culture is carried out at 30° C. to 40° C., preferably at 35° C. for 24 to 48 hours, preferably for 36 hours with Mueller- Hinton broth (manufactured by DIFCO) can be mentioned.
Then, the supernatant is collected from the culture obtained in the above-mentioned step (a) (step (b)). In this step (b), the collection of the supernatant may be carried out by centrifugation. Specific conditions of the centrifugation are not particularly limited, however, for example, the centrifugation may be carried out at 10,000 rpm to 40,000 rpm, preferably at 20,000 rpm for 20 minutes to 1 hour, preferably for 1 hour.
The pH of the supernatant collected in the above-mentioned step (b) is adjusted to 3 or lower, preferably 3.0, and the formed precipitate is collected (step (c)). In this step (c), the adjustment of the pH can be carried out with an acid such as sulfuric acid or hydrochloric acid. Further, after the adjustment of the pH, the supernatant is preferably let stand for 8 to 24 hours, preferably for 12 to 18 hours at 4 to 10° C., preferably at 4 to 5° C. Further, as for the collection of the precipitate formed by adjusting the pH, the collection may be carried out by centrifugation, ultrafiltration, lyophilization, dialysis or the like, preferably centrifugation may be carried out. Specific conditions of the centrifugation are not particularly limited, however, for example, the centrifugation may be carried out at 10,000 rpm to 40,000 rpm, preferably at 20,000 rpm for 20 minutes to 1 hour, preferably for 1 hour.
Lastly, the precipitate collected in the above-mentioned step (c) is subjected to extraction with ethanol (step (d)). By this step (d) , DM0507 of the present invention can be obtained. As the method of extracting DM0507 from the precipitate, a method in which ethanol is added to the precipitate, the mixture in a state where the precipitate floats therein is let stand for about 15 minutes to 1 hour, and DM0507 is extracted in ethanol and other methods can be mentioned.
The thus obtained DM0507 of the present invention has a broad spectrum of antimicrobial activity against the following microorganism Groups (A) to (D):
DM0507 of the present invention exhibits a high antimicrobial activity particularly against Legionella pneumophila serotype 1, Porphyromonas gingivalis and Propionibacterium acnes among these microorganisms. Next to them, it exhibits a high antimicrobial activity against Clostridium difficile, Campylobacter jejuni, Campylobacter coli and Stenotrophomonas maltophilia, and next to them, Aeromonas salmonicida, Mycoplasma gallisepticum and Mycoplasma synoviae.
Since DM0507 of the present invention has an antimicrobial activity against a broad spectrum of microorganisms as described above, it can be used for an antimicrobial agent containing the substance as an active ingredient, an antimicrobial product, a food or drink, etc. containing the substance.
For the production of the antimicrobial agent containing DM0507 of the present invention as an active ingredient, DM0507 and an appropriate known pharmaceutically acceptable medicinal carrier may be combined and formulated into a preparation by a standard method. The content of DM0507 in this antimicrobial agent is not particularly limited as long as it is an amount capable of exhibiting the antimicrobial activity. However, for example, the MIC (minimum inhibitory concentration) of DM0507 against Acinetobacter junii is measured, and a product may contain DM0507 at the MIC or higher concentrations, preferably 2-to 10-fold the MIC. Hereinafter, a method of measuring the MIC against Acinetobacter junii by a broth microdilution method is shown.
<Method of measuring MIC against Acinetobacter junii by broth microdilution method>
The measurement was carried out in two series for each sample, and the concentration levels of DM0507 are set up to 10240-fold dilutions by serially diluting a 10-fold dilution 2-fold. First, 100 μl of cation-adjusted Mueller-Hintonbroth (hereinafter referred to as CAMHB) is dispensed into each well of a 96-well flat-bottomed microplate. Into the first well to which DM0507 is added, 180 μl of CAMHB is dispensed. Then, 20 μl of DM0507 is added to the first well to make a 10-fold dilution, which is serially diluted 2-fold with a 100-μl aliquot thereof up to 10240-fold. Isolation culture of Acinetobacter junii is carried out on the previous day and culture is carried out in advance with MHA for 18 to 24 hours. The freshly cultured cells on an agar medium is adjusted to a 0.5 McFarland standard with physiological saline and is further diluted 10-fold, and the cell density is adjusted to 107 cfu/ml. Five microliters of the adjusted bacterial suspension is inoculated into each well to give a final inoculum density of 5×105 cfu/ml (5×104 cfu/100 μl). As controls, a well containing only CAMHB and the bacterial suspension and a well containing only CAMHB are prepared. The microplate is incubated at 35° C. for 18 hours, and the MIC is determined to be the lowest dilution that completely inhibited the growth by visual observation.
Further, by incorporating or impregnating DM0507 of the present invention directly or as an antimicrobial agent produced as described above in the existing products shown below, antimicrobial products as shown below can be produced.
<Quasi-drugs, reagents, gargles, etc.>
Among these antimicrobial products, particularly cosmetic lotions and dentifrices are preferred. The production of these antimicrobial products may follow the production process for a common product except for adding an effective amount of DM0507 of the present invention to raw materials of the products.
Further, DM0507 of the present invention can be incorporated in foods and drinks such as sweet stuffs including gums, candies, cookies, tablet-type sweet stuffs and the like, supplements and refreshing drinks. Among these foods and drinks, particularly gums and candies are preferred. By the intake of DM0507 of the present invention on a daily basis by incorporating DM0507 in such a common food or drink, it can be a health food that eliminates bacteria leading to a periodontal disease, Helicobacter pylori or the like, or inhibits the colonization of such bacteria. The production process for these foods and drinks may follow the production process for a common food or drink except for adding an effective amount of DM0507 of the present invention to raw materials of the foods and drinks.
Hereinafter, the present invention will be described by way of Examples, however, the present invention is not limited to these Examples.
<Test strains>
First, each Bacillus subtilis strain was subcultured for three passages on Mueller-Hintons agar medium (manufactured by Eiken Chemical Co., Ltd.) . Then, one platinum loop of each strain was inoculated into 10 ml of sterile Mueller-Hinton broth (manufactured by DIFCO), and shaking culture was carried out at 35° C. for 24 hours.
Each culture medium after the shaking culture was dispensed into a 1.5 ml microtube, respectively, and centrifugation was carried out at 15,000 rpm for 10 minutes. Then, the centrifuged supernatant was collected, and filtered through a 0.45 μm filter. Then, this filtered culture supernatant was impregnated in a paper disk with a diameter of 6.5 mm (manufactured by DIFCO). On the contrary, Porphyromonas gingivalis to be used as the indicator for antimicrobial activity was anaerobically cultured in GAM bouillon liquid (manufactured by Nissui Pharmaceutical Co., Ltd.) in advance. Then, GAM agar medium (manufactured by Nissui Pharmaceutical Co., Ltd.) was autoclaved and incubated at 50° C. Then, the cultured medium of Porphyromonas gingivalis anaerobically cultured in advance was mixed therewith, which was pored into a dish and allowed to solidify. The paper disk impregnated with each of the filtered culture media of Bacillus subtilis strains was placed on the center of the dish, and anaerobic culture was carried out at 35° C. for 48 hours. The diameter of inhibitory zone of each Bacillus subtilis strain for Porphyromonas gingivalis was measured at 48 hours after the initiation of the culture. The results are shown in Table 1.
From Table 1, it was found that the culture supernatants of DB9011 strain and MBI 600 strain exhibit a high antimicrobial activity against Porphyromonas gingivalis.
DB901 strain grown on a slant medium and stored in a refrigerator was subcultured on Mueller-Hintons agar medium (manufactured by Eiken Chemical Co., Ltd.), and cultured at 35° C. for 24 hours to form a colony. Then, the above-mentioned one colony was inoculated into 10 ml of Mueller-Hinton broth (manufactured by DIFCO) and shaking culture was carried out at 35° C. for 24 hours. Finally, 1 ml of the above culture medium was inoculated into 3 L of Mueller-Hinton broth autoclaved in advance, and shaking culture was carried out at 35° C. for 30 hours at 200 rpm, whereby a culture medium was obtained.
(2) Extraction of antimicrobial active substance DM0507
(3) Measurement of physiological properties of antimicrobial active substance DM0507
<IR measurement>
As a result of performing IR measurement of DM0507 under the following conditions, peaks were observed at 3060.48, 2958.27, 2927.41, 2871.49, 2856.06, 1737.55, 1650.77, 1573.63, 1558.20, 1469.49, 1403.92, 1274.72, etc. (all the units are cm−1) (
(Measurement conditions)
Measurement apparatus: HORIBA FT-710 (manufactured by Horiba Ltd.)
Measurement method: KBr method
Measurement temperature: room temperature
<NMR measurement>
Measurement of antimicrobial activity
By using the antimicrobial active substance DM0507 obtained in Example 1, the antimicrobial activity against the following test strains were measured.
<Test strains>
(1) Assay
(2) Pour method
(3) Streak method
S. aureus MSSA
S. aureus MRSA
S. hyicus
M. luteus ATCC 9341
S. mutans JCM 5705
S. suis
S. pneumoniae
S. pyogenes
E. gallinarum
B. subtilis DB9011 strain
B. subtilis ATCC 6633
B. cereus ATCC 11778
A. pyogenes
V. parahaemolyticus ATCC 17802
A. salmonicida
A. hydrophila
A. actinomycetemcomitans JCM
A. pleuropneumoniae type 2
H. parasuis
P. multocida type D
P. haemolytica
P. trehalosi
E. coil
S. typhimurium
S. choleraesuis
K. pneumoniae ATCC 10031
P. aeruginosa
P. aeruginosa
P. aeruginosa pump deficient strain
A. junii
Acinetobacter. sp.
S. maltophilia
L. pneumophilia serotype 1
M. gallisepticum
M. synoviae
C. jejuni
C. coli
H. pylori ATCC 43526
C. perfringens
C. difficile
P. acnes JCM 6425
B. fragilis
P. gingivalis JCM 8525
T. forsythensis JCM 10827
L. acidophilus JCM 1132
B. bifidum JCM 1255
A. prevotii JCM 6508
F. nucleatum
C. albicans
Cryptococcus sp.
A. niger
F. oxysporum
M. gallisepticum or M. synoviae was subcultured for three passages at 35° C. using Fray's broth (internally prepared) while the growth thereof was confirmed by the change of the color into yellow. A sterile cotton swab on a wood stick was impregnated with the broth of the third passage whose color had changed into yellow, and streaking was carried out in three directions on Fray's agar medium.
T. forsythensis requires N-acetylmuramic acid for its growth, therefore, it was cultured by placing a disk containing 1.5% N-acetylmuramic acid on the center of the medium. Fifteen milligrams of N-acetylmuramic acid was dissolved in 1 ml of purified water, and the solution was filtered with a 0.45 μm filter. Then, 20 μl of the solution was impregnated in respective paper disks with a diameter of 8 mm, and the disks were dried at room temperature, which were used as disks containing 1.5% N-acetylmuramic acid.
A. niger and F. oxysporum were cultured at 25° C. for 7 days using a PDA slant medium. To the slant medium on which the fungi were grown, 2 ml of physiological saline supplemented with 0.1% Tween 80 was added and mixed gently, whereby a spore solution was prepared. The spore solution was put in a hemocytometer and the number of spores was determined. Then, the spore number was adjusted to 1 × 106/ml with physiological saline supplemented with 0.1% Tween 80. A sterile cotton swab on a wood stick was impregnated with the spore solution, and streaking was carried out in three directions on a PDA plate.
The above results demonstrated that DM0507 of the present invention has an extremely broad antimicrobial spectrum, and the potency of the antimicrobial activity varies depending on the strains.
Since DM0507 of the present invention has an antimicrobial activity against a broad spectrum of strains, it can be used for an antimicrobial agent, antimicrobial product, a food or drink, etc. having an excellent antimicrobial activity.
[
[
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/JP05/20318 | 11/4/2005 | WO | 00 | 10/16/2007 |