U.S. patent application number 16/158548 was filed with the patent office on 2019-02-07 for equol-producing lactic acid bacteria-containing composition.
This patent application is currently assigned to OTSUKA PHARMACEUTICAL CO., LTD.. The applicant listed for this patent is OTSUKA PHARMACEUTICAL CO., LTD.. Invention is credited to Toshimi SUZUKI, Shigeto UCHIYAMA, Tomomi UENO.
Application Number | 20190038684 16/158548 |
Document ID | / |
Family ID | 33549734 |
Filed Date | 2019-02-07 |
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United States Patent
Application |
20190038684 |
Kind Code |
A1 |
UCHIYAMA; Shigeto ; et
al. |
February 7, 2019 |
EQUOL-PRODUCING LACTIC ACID BACTERIA-CONTAINING COMPOSITION
Abstract
An equol-producing lactic acid bacteria-containing composition
comprises, as an essential component thereof, a lactic acid
bacterial strain belonging to the genus Lactococcus having an
ability to utilize at least one daidzein compound selected from the
group consisting of daidzein glycosides, daidzein, and
dihydrodaidzein to produce equol. Such a composition is effective
for the prevention and alleviation of malaise inclusive of
climacteric disturbance in middle-aged and elderly women for which
no effective prophylactic method or alleviating means has
heretofore been available.
Inventors: |
UCHIYAMA; Shigeto;
(Miyaki-gun, JP) ; UENO; Tomomi; (Kurume-shi,
JP) ; SUZUKI; Toshimi; (Kurume-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OTSUKA PHARMACEUTICAL CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
OTSUKA PHARMACEUTICAL CO.,
LTD.
Tokyo
JP
|
Family ID: |
33549734 |
Appl. No.: |
16/158548 |
Filed: |
October 12, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14034824 |
Sep 24, 2013 |
10098915 |
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16158548 |
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10562687 |
Dec 28, 2005 |
8765445 |
|
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PCT/JP2004/009484 |
Jun 29, 2004 |
|
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14034824 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A23Y 2220/00 20130101;
A61K 35/744 20130101; A23L 33/135 20160801; A61P 5/32 20180101;
A61P 5/30 20180101; A61P 3/06 20180101; A61P 15/00 20180101; A61K
35/747 20130101; A61P 15/12 20180101; C12R 1/46 20130101; A23C
11/106 20130101; C12P 17/06 20130101; A61P 19/00 20180101; A61P
9/12 20180101; A23C 9/123 20130101; A61P 19/10 20180101; A61P 35/00
20180101 |
International
Class: |
A61K 35/747 20060101
A61K035/747; A23L 33/135 20060101 A23L033/135; C12R 1/46 20060101
C12R001/46; A23C 9/123 20060101 A23C009/123; A61K 35/744 20060101
A61K035/744; A23C 11/10 20060101 A23C011/10; C12P 17/06 20060101
C12P017/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 30, 2003 |
JP |
2003-187831 |
Claims
1. An equol-producing lactic acid bacteria-containing composition
comprising, as an essential component thereof, a lactic acid
bacterial strain belonging to the genus Lactococcus having an
ability to utilize at least one daidzein compound selected from the
group consisting of daidzein glycosides, daidzein, and
dihydrodaidzein to produce equol.
2. The composition according to claim 1, wherein said lactic acid
bacterial strain belonging to the genus Lactococcus is Lactococcus
garvieae.
3. The composition according to claim 2, wherein said lactic acid
bacterial strain belonging to Lactococcus is Lactococcus 20-92
deposited under FERM BP-10036.
4. The composition according to claim 1 further comprising at least
one member selected from the group consisting of daidzein compounds
and daidzein compound-containing ingredients.
5. The composition according to claim 4, wherein the daidzein
compound-containing ingredient is soybean flour or soy milk
6. The composition according to claim 4 which is in the form of a
beverage or a milk product.
7. The composition according to claim 4 further comprising
equol.
8. The composition according to claim 7 which is in the form of a
fermentation product of soy milk.
9. A method of producing equil comprising the step of letting a
lactic acid bacterial strain belonging to the genus Lactococcus
having an ability to utilize a daidzein compound to produce equol
act on at least one member selected from the group consisting of
daidzein compounds and daidzein compound-containing
ingredients.
10. The method according to claim 9, wherein said lactic acid
bacterial strain belonging to the genus Lactococcus is Lactococcus
garvieae.
11. The method according to claim 10 wherein said lactic acid
bacterial strain belonging to the genus Lactococcus is Lactococcus
20-92 deposited under FERM BP-10036.
12. The method according to claim 9, wherein the daidzein
compound-containing ingredient is soybean flour or soy milk.
13. A lactic acid bacterial strain belonging to the genus
Lactococcus as deposited under FERM BP-10036.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Divisional of U.S. application Ser.
No. 14/034,824, filed on Sep. 24, 2013, which is a Continuation of
U.S. application Ser. No. 10/562,687 filed Dec. 28, 2005 (now U.S.
Pat. No. 8,765,445), which is a National Stage Entry of PCT
International Application No. PCT/JP2004/009484 filed Jun. 29,
2004, which claims benefit of Japanese Patent Application No.
2003-187831 filed Jun. 30, 2003. The above-noted applications are
incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to equol-producing lactic acid
bacterial strain, a composition comprising said lactic acid
bacterial strain, and a method of producing equol by utilizing said
lactic acid bacterial strain.
BACKGROUND OF THE INVENTION
[0003] It has heretofore been reported mostly in Europe and the
United States of America that isoflavone (soy isoflavone) contained
in soybeans has prophylactic efficacies (antiestrogen effect) in
breast cancer, carcinoma of the prostate, and other diseases and
that it has alleviating efficacies (estrogenic-like effect) in
climacteric and postmenopausal osteoporosis, hyperlipidemia,
hypertension, etc. (H. Adlercreutz et al., (1992) Lancet, 339,
1233; H. Adlercreutz et al., (1992) Lancet, 342, 1209-1210; D. D.
Baird et al., (1995) J. Clin. Endocrinol. Metab., 80, 1685-1690; A.
L. Murkies et al., (1995) Maturitas., 21, 198-195; and D. Agnusdei
et al., (1995) Bone and Mineral., 19 (Supple), S43-S48).
[0004] Recently, however, doubts have been cast on the clinical
efficacy of soy isoflavone and, instead, it is reported that equol
as the active metabolite of soy isoflavone is a key factor in the
expected efficacies in clinical application. Thus, several reports
are available arguing that in breast cancer, carcinoma of the
prostate, and climacteric and postmenopausal osteoporosis, the
efficacy of soy isoflavone is surpassed by that of equol, the
metabolite of soy isoflavone (D. Ingram et al., (1997) Lancet, 350,
990-994; A. M. Duncan et al., (2000) Cancer Epidemiology,
Biomarkers & Prevention, 9, 581-586; C. Atkinson et al., (2002)
J. Nutr., 32(3), 595S; H. Akaza et al., (2002) Jpn. J. Clin.
Oncol., 32(8), 296-300; and S. Uchiyama et al., (2001) Ann. Nutr.
Metab., 45, 113(abs)).
[0005] Moreover, many lectures were delivered on the subject of
equol in the 4th International Symposium on the Role of Soy in
Preventing and Treating Chronic Disease (San Diego, USA, 2001), and
in December 2002 a comprehensive review of studies on equol was
also reported. Thus, it is getting more or more accepted in
academic circles that equol is the very entity of efficacies of soy
isoflavone (K. D. R. Settchell et al., (2002) J. Nutr., 132,
3577-3584).
[0006] Furthermore, compared with soy isoflavone, equol is
delivered to tissues such as the breast tissue and prostatic tissue
with by far greater efficiency and, from this fact, the
physiological significance of equol is endorsed (J. Maubach et al.,
(2003) J. Chromatography B., 784, 137-144; T. E. Hedlund et al.,
(2003) The Prostate, 154, 68-78).
[0007] Equol is produced by the intestinal flora and the
involvement of individual difference in its production has been
reported. It is also reported that equol producers among the
Japanese account for about 50% (S. Uchiyama et al., (2001) Ann.
Nutr. Metab., 45, 113 (abs)). Individuals who cannot produce equol
are suspected to be lacking in equol-producing bacteria in their
intestine. In such individuals, it is suspected that the expected
antiestrogen and estrogenic-like effects may not be expected even
if processed soybean foods are ingested. In order that the expected
effects may be expressed in such individuals, it seems to be a
reasonable course of action to have them ingest equol-producing
bacteria or equol as such.
[0008] Based on the above idea, the inventors had conducted
intensive investigations and isolated from human stools novel 3
strains of microorganisms and identified them: namely Bacterioides
E-23-15 (FERM BP-6435), Streptococcus E-23-17 (FERM BP-6436), and
Streptococcus A6G225 (FERM BP-6437), as equol producing-bacteria
suitable for the expression of said antiestrogen and
estrogenic-like effects, among other effects, and applied for a
patent claiming inventions concerning these equol-producing strains
of microorganisms and utilization of the microorganisms
(WO99/07392).
DISCLOSURE OF INVENTION
[0009] The inventors conducted further studies and succeeded in the
isolation and characterization of a lactic acid bacterial strain
belonging to the genus Lactococcus which are capable of utilizing
daidzein glycoside, daidzein, or dihydrodaidzein to produce equol
as a novel strain of microorganism which is fundamentally different
from the previously isolated and identified microorganisms. The
present invention has been developed on the basis of the above
isolation and identification of this novel strain of lactic acid
bacterium.
[0010] The present invention subsumes the following inventions
summarized in paragraphs 1-13.
[0011] Item 1. An equol-producing lactic acid bacteria-containing
composition comprising, as an essential component thereof, a lactic
acid bacterial strain belonging to the genus Lactococcus having an
ability to utilize at least one daidzein compound selected from the
group consisting of daidzein glycosides, daidzein, and
dihydrodaidzein to produce equol.
[0012] Item 2. The composition according to Item 1, wherein said
lactic acid bacterial strain belonging to the genus Lactococcus is
Lactococcus garvieae.
[0013] Item 3. The composition according to Item 2, wherein said
lactic acid bacterial strain belonging to Lactococcus is
Lactococcus 20-92 deposited under FERM BP-10036.
[0014] Item 4. The composition according to Item 1 further
comprising at least one member selected from the group consisting
of daidzein compounds and daidzein compound-containing
ingredients.
[0015] vItem 5. The composition according to Item 4, wherein the
daidzein compound-containing ingredient is soybean flour or soy
milk.
[0016] Item 6. The composition according to Item 4 which is in the
form of a beverage or a milk product.
[0017] Item 7. The composition according to Item 4 further
comprising equol.
[0018] Item 8. The composition according to Item 7 which is in the
form of a fermentation product of soy milk.
[0019] Item 9. A method of producing equil comprising the step of
letting a lactic acid bacterial strain belonging to the genus
Lactococcus having an ability to utilize a daidzein compound to
produce equol act on at least one member selected from the group
consisting of daidzein compounds and daidzein compound-containing
ingredients.
[0020] Item 10. The method according to Item 9, wherein said lactic
acid bacterial strain belonging to the genus Lactococcus is
Lactococcus garvieae.
[0021] Item 11. The method according to Item 10 wherein said lactic
acid bacterial strain belonging to the genus Lactococcus is
Lactococcus 20-92 deposited under FERM BP-10036.
[0022] Item 12. The method according to Item 9, wherein the
daidzein compound-containing ingredient is soybean flour or soy
milk.
[0023] Item 13. A lactic acid bacterial strain belonging to the
genus Lactococcus as deposited under FERM BP-10036.
[0024] The equol-producing lactic acid bacteria-containing
composition of the invention described in detail bellow.
(1) The Lactic Acid Bacterial Strain Belonging to the Genus
Lactococcus
[0025] The equol-producing lactic acid bacteria-containing
composition of the invention comprises, as an essential component
thereof, lactic acid bacterial strain belonging to the genus
Lactococcus having an ability (metabolic activity) to utilize at
least one daidzein compound selected from the group consisting of
daidzein glycosides, daidzein, and dihydrodaidzein and thereby
produce equol.
[0026] A specific example of said lactic acid bacterial strain is
Lactococcus 20-92 (FERM BP-10036) which the inventors isolated from
human stools and identified de novo.
[0027] The bacteriological characteristics of the lactic acid
bacterial strain are described in detail bellow.
[0028] I. State of Growth on the Medium
[0029] This strain shows good or normal growth on EG
(Eggerth-Gagnon) agar, BL (Blood Liver) agar, and GAM (Gifu
Anaerobic Medium) when cultured anaerobically in an anaerobic jar
with steel wool at 37.degree. C. for 48 hours or cultured
aerobically at 37.degree. C. for 48 hours. The colonial morphology
is raised in a circular or convex manner, with both the surface and
peripheral edge being smooth, and assumes a gray-white color on EG
agar and a tan-brown color on BL agar. Morphologically, it is a
Gram-positive diplococcus. This strain is not sporogenic.
[0030] II. Biochemical Characteristics [0031] (1) Optimum
temperature for growth: 37.degree. C. [0032] (2) Optimum pH for
growth: 7.0 [0033] (3) Liquefaction of gelatin: - [0034] (4)
Production of acetoin from pyruvic acid: + [0035] (5) Hydrolysis of
hippuric acid: - [0036] (6) Hydrolysis of esculin: + [0037] (7)
Pyrrolidonyl arylamidase: + [0038] (8) .alpha.-Galactosidase: -
[0039] (9) .beta.-Galactosidase: - [0040] (10) .beta.-Glucronidase:
- [0041] (11) Alkaline phosphatase: - [0042] (12) Leucine
arylamidase: + [0043] (13) Arginine dihydrase: + [0044] (14)
Assimilation of carbon sources [0045] D-Ribose + [0046] L-Arabinose
- [0047] D-Mannitol + [0048] D-Sorbitol - [0049] Lactose - [0050]
D-Trehalose + [0051] Inulin - [0052] D-Raffinose - [0053] Starch +
[0054] Glycogen - [0055] (15) Organic acid composition after
utilization of peptone or glucose
[0056] Using PYF (peptone-yeast extract Fields) medium (peptone
content: ca 5%) used as sugar utilization medium and PYF medium
supplemented with glucose at a final concentration of 0.5%, the
strain of the invention was cultured aerobically at 37.degree. C.
for 72 hours and the organic acids in the cultures were assayed by
HPLC. The results (unit: mM) are presented below in Table 1
TABLE-US-00001 TABLE 1 Organic acid Peptone Glucose Maleic acid nd
nd Succinic acid 0.00 0.01 Lactic acid 3.33 27.35 Formic acid 1.13
0.88 Acetic acid 3.32 0.57 Pyroglutamic acid 0.12 0.25 Propionic
acid nd nd i-Butyric acid nd nd n-Butyric acid nd nd i-Valeric acid
nd nd n-Valeric acid nd nd nd = not detected
[0057] From the above cultural and biochemical characteristics, the
strain of the invention is classified into Lactococcus garvieae
which is a gram-positive coccus but differs from its type strain
(Schleifer, K. H., Kraus, J., Dvorak, C., Kilpper-Balz, R.,
Collins, M. D. and Fischer, W. Transfer of Streptococcus lactis and
related streptococci to the genus Lactococcus gen. nov. Syst. Appl.
Microbiol., 6, 183-195, 1985; ATCC43921 (JCM10343) and ATCC49156
(JCM8735)) in the utilization of starch.
[0058] Therefore, the inventors named this strain Lactococcus 20-92
and deposited it with the National Institute of Advanced Industrial
Science and Technology International Patent Organism Depositary,
AIST Tsukuba Central 6, 1-1, Higashi 1-Chome Tsukuba-shi,
Ibaraki-ken 305-8566, Japan as of Jan. 23, 2003, under the
accession number of FERM P-19189. This microorganism is now placed
under Budapest Treaty deposit, and the accession number is FERM
BP-10036.
[0059] This strain was found to assimilate glucose and, then,
elaborate lactic acid (L-lactic acid), verifying that it is a
member of homofermentative lactic acid bacteria.
[0060] Furthermore, sequencing of the 16SrRNA of this strain
revealed 99.189% homology with the type strain Lactococcus garvieae
(JCM10343) and 99.375% homology with Enterococcus seriolicida,
JCM8735).
[0061] Incidentally, since Enterococcus seriolicida referred to
above was akin to Lactococcus garvieae in DNA-DNA homology
analysis, it was reclassified into Lactococcus garvieae in 1996.
Therefore, Lactococcus garvieae has two type strains (JCM8753
strain and 10343 strain) which are dissimilar in origin.
Enterococcus seriolicida (JCM8735) was derived from the kidney of
infected yellowtail and the intrinsic Lactococcus garvieae
(JCM10343) was derived from bovine mastitis.
[0062] To explore the relative homology of Lactococcus 20-92 with
the above two type strains, a phenotypic comparison was made. The
results are presented below in Table 2.
TABLE-US-00002 TABLE 2 Strain of Characteristics invention JCM10343
JCM8735 Deamination .+-. .+-. .+-. (Arg .fwdarw. NH.sub.3)
Temperature dependence of growth 10.degree. C. + + + 15.degree. C.
+ + + 30.degree. C. + + + 37.degree. C. + + + 40.degree. C. + + -
45.degree. C. - - - pH dependence of growth pH 4.5 .+-. .+-. .+-.
pH 7.5 + + + pH 9.6 + + + Salt tolerance (NaCl) 6.5 + + +
Peptidoglycan Lys-Ala-Gly Lys-Ala-Gly Lys-Ala-Gly Quinone type
MK-8,9 MK-8,9 No quinone MK denotes menaquinone
[0063] It will be apparent from Table 2 that the present strain
Lactococcus 20-92 was in agreement with the type strain (JCM10343)
of Lactococcus garvieae in phenotype but was different from the
type strain (JCM8735) of Enterococcus seriolicida in growth
behavior at 40.degree. C. and in the production or non-production
of quinone. Accordingly the present strain was judged to be akin to
Lactococcus garvieae (JCM10343).
[0064] The present strain Lactococcus 20-92 can be classed among
Milk-cultured Lactococci in the GRAS [acronym of Generally
Recognized As Safe list by FDA (Food and Drug Administration,
U.S.A.)] and its safety as a food is considered to be high.
[0065] With regard to Lactococcus garvieae, there is not a report
ever suggesting its pathogenicity to human beings and there is no
production of virulent substances such as toxins, either, so that
this bacterial species is generally acknowledged to be a species of
high safety.
[0066] Moreover, Lactococcus garvieae has so far been detected in
mozzarella cheese, raw milk, processed meat products under
low-temperature storage, plaa-som (a fermented fish product widely
consumed in Thailand), and Toma Piemontese cheese which is an
artisanal protected denomination origin (PDO) Italian cheese, i.e.
traditional cheese in Italy, among others, and reportedly this
microorganism is detected at a high incidence of the order of
10.sup.5 cells/gram from plaa-som and 10.sup.8 cells/gram from Toma
Piemontese cheese, but this food has a long history of eating
assuring the safety of this organism. (P-M. Christine et al.,
(2002) Int. J. Food Microbiol., 73, 61-70; M. G. Fortina, et al.,
(2003), Food Microbiol., 20, 379-404).
[0067] On the other hand, Enterococcus seriolicida is reportedly
pathogenic to cultured fishes such as yellowtail. Since Lactococcus
20-92, which is, thus, a strain of Lactococcus garvieae, is
considered to be phylogenetically related to Enterococcus
seriolicida, there was an apprehension of its pathogenic potential
to cultured fishes. However, the studies by the inventors comparing
the electronmicrograph of Lactococcus 20-92 with that of the
pathogenic counterpart (Enterococcus seriolicida KG) revealed that
unlike said pathogenic strain, the strain of the invention has no
capsule on the cell surface. Therefore, the present strain is
considered to have no pathogenicity, nor does it present with an
ecological contamination problem. This conclusion is also
corroborated by the description in the following literature. Thus,
Yoshida et al. argue about the pathogenicity of microbial cells to
cultured fishes that a capsule present on the cell surface inhibits
phagocytosis by macrophages, with the result that the particular
bacteria are not killed but septicemia is induced systemically in
cultured fishes infected with the bacteria (T. Yoshida, et al.,
(1996) Dis. Aquat. Org., 25, 81-86).
[0068] Furthermore, the present strain Lactococcus 20-92 retains
the desired equol-producing ability (activity) even in the case of
direct fermentation in milk and has the characteristic that for the
maintenance of this equol-producing ability, no special culture
medium is required. Thus, by carrying out a fermentation in soy
milk as used alone, the strain utilizes daidzein compounds in the
soy milk to elaborate equol.
[0069] Heretofore, there is no report available on lactic acid
bacteria of the genus Lactococcus which ever have such an
equol-producing ability. Therefore, the present invention further
provides a novel strain of lactic acid bacterium having such an
equol-producing ability.
(2) Daidzein Compounds and Daidzein Compound-Containing
Ingredients
[0070] Daidzein compounds, which are utilized by the present strain
Lactococcus 20-92, include a daidzein glycoside, daidzein, and
dihydrodaidzein. A specific example of said daidzein glycoside is
daidzin. Daidzin is an isoflavone glycoside having daidzein as the
aglycone (daidzein glycoside). Referring to daidzin, it is utilized
by said strain of microorganism to liberate daidzein which is
further utilized by the strain to give dihydrodaidzein, from which
equol is finally produced.
[0071] In the present invention, said daidzein compound is used as
the substrate. The substrate includes not only daidzein compounds
but also various materials or ingredients containing the same. As a
representative example of said material or ingredient containing
said daidzein compounds (referred to as daidzein
compound-containing ingredient), soy isoflavone can be mentioned.
Soy isoflavone is already available from commercial sources and, in
the present invention, such commercial products, for example
"Fujiflavone P10" (registered trademark) from Fujicco Co., Ltd.,
can be used. Moreover, said daidzein compound-containing ingredient
includes not only soy isoflavone but also plant tissues as such,
e.g. kudzu (=Pueraria thurbergiana Benth) and root of kudzu
(arrowroot), red clove, alfalfa, etc., and isoflavone derivatives
originating therefrom.
[0072] Further examples of said daidzein compound-containing
ingredient includes not only the above-mentioned food materials
such as soybean, kudzu, root of kudzu, red clove, alfalfa, etc. but
also processed products thereof, such as soybean meal (soybean
flour), boiled soybeans, t fu (soybean curd), fried bean curd, soy
milk, soybean hypocotyl extract, etc., fermentation products
thereof, such as natto (fermented soybeans), soy sauce, miso,
tempeh, and fermented soy beverages. These materials invariably
contain daidzein compounds. Moreover, these not only contain
daidzein compounds but also estrogenic isoflavones, such as
genistein and its glycosides (genistin etc.); glycitein and its
glycosides (glycitin etc.); biochanin A and formononetin which are
partially methylated daidzein and genistin precursors and can be
used with advantage in the present invention.
(3) Composition of the Invention
(3-1) An Equol-Producing Lactic Acid Bacteria-Containing
Composition
[0073] The equol-producing lactic acid bacteria-containing
composition of the invention comprises, as an essential component
thereof, actic acid bacterial strain belonging to the genus
Lactococcus having an ability to act on the substrate daidzein
compound or daidzein-containing ingredient to produce equol, with
the above-mentioned Lactococcus 20-92 being a representative
example. The lactic acid bacterial strain for use as said essential
component usually are viable bacterial strain but are not limited
to these but may be any of its cultures, crude or purified
preparations of such cultures, which contains isolated cells, and
lyophilizates thereof.
[0074] The cultures of said bacterial strain can be obtained
typically by the procedure comprising culturing the strain in a
medium suited for its growth, for example MRS medium, at 37.degree.
C. for about 48 hours. Following the cultivation, the cells can be
recovered by, for example, centrifuging the culture at 3,000 rpm
(4.degree. C.) for 10 minutes. These can be purified in the
conventional manner. Moreover, these cells can be lyophilized. The
resulting lyophilizates can also be utilized as the active
component of the composition of the invention.
[0075] All that is necessary for the composition of the invention
is that it contains the bacteria (cells or equivalent) as said
active component but, if desired, the composition may be
supplemented with nutrients suited for the maintenance (or growth)
of the microorganism as said active component. The nutrients
mentioned above may for example be the nutrient media for culture
of the respective microorganisms, such as BHI, EG, BL and GAM, as
mentioned hereinbefore.
[0076] Examples of the other nutrients include various
oligosaccharides, such as lactooligosaccharide, soy
oligosaccharide, lactulose, lactitol, fructooligosaccharide, and
galactooligosaccharide. The amount of such oligosaccharides is not
particularly restricted but is preferably selected from a range
such that the final concentration thereof in the composition of the
invention will be about 1-3 weight %.
[0077] The above composition of the invention, when taken orally,
expresses the desired equol-producing activity in the recipient's
body. Generally the Japanese have the habit to eat daidzein
compound-containing foods, typically the above-mentioned food
materials or ingredients, e.g. soybeans, secondary products
thereof, and fermentation products thereof and, therefore, the
intake of the composition of the invention results in the
production of equol in vivo.
[0078] Furthermore, where necessary, the composition of the
invention may be supplemented with suitable amounts of various
vitamins, trace metal elements, and so forth. Examples of said
vitamins include vitamin B, vitamin D, vitamin C, vitamin E, and
vitamin K [particularly MK-7 (menaquinone-7) derived from Bacillus
natto]. Examples of said trace metal elements are zinc, selenium,
iron, manganese, etc.
[0079] The quantity of the microorganism to be formulated in the
composition of the invention can be judiciously selected according
to the kind of bacterial strain used. Taking Lactococcus 20-92 as
an example, the number of organisms (viable cell count) is
preferably adjusted to about 10.sup.8.about.10.sup.9 cells/100 g
composition. The viable cell count is determined as follows. A
sample dilution is coated onto an agar medium for bacterial culture
and cultured aerobically at 37.degree. C. and the colonies formed
are counted. The quantity of the microorganism described above can
be judiciously adjusted according to the form of the composition to
be prepared using the above-mentioned quantity as a reference.
(3-2) The Daidzein Compound-Containing Composition of the
Invention
[0080] The composition of the invention may further contain, if
necessary, at least one member selected from the group consisting
of the aformentioned diadzein compounds and daidzein
compound-containing ingredients. Among various kinds of daidzein
compound and daidzein compound-containing ingredient, soybean
hypocotyls and food ingredients prepared starting with the
hypocotyls, are particularly preferred, and, among these,
water-soluble or emulsified food ingredients are still more
preferred. Among other preferred examples of said daidzein
compound-containing ingredient are soybean flour and soy milk.
[0081] Due to the substrate contained in the formulation, a person
not accustomed to eating soybeans and the like food ingredients can
take the composition orally, and the ingested microorganism
utilizes the formulated substrate to produce the objective equol in
the body.
[0082] The amount of said daidzein compound and/or daidzein
compound-containing ingredient in the composition is not
particularly restricted but may reasonably be about 10-25 mg which
is equivalent to the usual daily intake by the average
Japanese.
(3-3) Equol-Containing Composition of the Invention
[0083] The composition of the invention may further contain
equol.
[0084] Generally, one's appetite for a food is whetted when the
food material is caused to undergo lactic acid fermentation, for
instance. Moreover, Lactococcus 20-92, which is a representative
example of microorganism for use in the composition of the
invention, has a very high equol-producing ability (activity). The
present invention further provides an equol-containing composition,
such as fermented soy milk, which is prepared by permitting said
strain of microorganism to act on a daidzein compound-containing
ingredient such as soy milk, and thereby let it utilize the
daidzein compound in the soy milk to elaborate equol.
[0085] As the substrate for use in this aspect of the invention,
the above-mentioned various kinds of daidzein compound and daidzein
compound-containing ingredient can be employed. Among these,
solutions or emulsions prepared from soy milk, soy flour or the
like are preferred.
[0086] A preferred specific example of the equol-containing
composition of the invention is the fermentation product obtained
by a process which comprises adding soy isoflavone or a food
material containing it to a suitable medium and culturing the
microorganism of the invention, preferably Lactococcus 20-92,
therein to cause fermentation. More particularly, such fermentation
can be effected by the procedure which comprises adding a
predetermined amount of the microorganism of the invention to a
mixture of a sterilized substrate solution and a nutrient medium
favorable for growth of the microorganism, such as BHI, EG, BL or
GAM, or to cow's milk, soy milk, or a vegetable juice which can be
used as food, and carrying out an anaerobic or aerobic fermentation
reaction at 37.degree. C. under stationary conditions for about
48-96 hours [where necessary, a pH control agent and a reducing
agent (e.g. yeast extract, vitamin K.sub.1, or the like) may be
added]. In the above procedure, the amount of the substrate may be
about 0.01-0.5 mg/mL and the inoculum size of the microorganism can
be selected from the range of about 1 to about 5%.
[0087] In this manner, the equol-containing composition of the
invention can be produced. This composition can be applied with
advantage in the above-described form of a fermentation product as
a food or a pharmaceutical product. Moreover, the produced equol
can be isolated and purified from the culture broth or fermentation
product in the per se known manner, optionally formulated with
suitable amounts of other food ingredients or the like, and
processed into suitable food forms or pharmaceutical product
forms.
[0088] The isolation and purification referred to above can be
achieved by, for example, adsorbing the fermentation product on an
ion exchange resin (DIAION HP20, product of Mitsubishi Kasei
Corporation), eluting it with methanol, and concentrating the
eluate to dryness.
[0089] The amount of equol in the composition of the invention is
selected according to the form of food or pharmaceutical product to
be produced and is not particularly restricted. Preferably,
however, the amount should generally be such that about 2-5 mg of
equol will be contained in each 100 g of the total composition.
[0090] The presence of equol in the product composition of the
invention can be confirmed by the method described hereinafter in
Test Example 1.
[0091] The equol-containing composition of the invention ranks high
on the safety scale because the active ingredient equol is a
naturally-occurring substance. Moreover, because it is prepared by
using the lactic acid bacterial strain, the risk of contamination
with chemicals originating from the production line is low. As
additional advantages, high yield and low cost as well as savory
taste and flavor as food can be mentioned.
(3-4) Forms of Food
[0092] The equol-producing lactic acid bacteria-containing
composition of the invention is generally processed into food forms
comprising the particular lactic acid bacterial strain as an
essential component in combination with a suitable edible
carrier.
[0093] Specific food forms of the composition of the invention
include the beverage form, milk product form other than said
beverage form (inclusive of fermented milk form), solid food form,
cell-containing microencapsulated form, and so forth. The
composition of the invention in the beverage form includes lactic
acid bacteria beverages and lactic acid bacteria-containing
beverages.
[0094] The terms "fermented milk" and "lactic acid bacteria
beverage" as used herein are in conformity with the definitions in
Article 2-37 "Fermented Milk" and Article 2-38 "Lactic Acid
Bacteria Beverage" of the "Regulations relating to the Ingredients
etc. of Milks and Milk Products" of the former Ministry of Health
and Welfare. Thus, "fermented milk" means a pasty or liquid
preparation resulting from the fermentation of a milk or a milk
(dairy) product with lactic acid bacteria or yeasts. Therefore, the
"fermented milk" includes not only products of beverage form but
also products of yogurt form. The "lactic acid bacteria beverage"
means a beverage prepared by using a pasty or liquid product
resulting from the fermentation of a milk or a milk product with a
lactic acid-fermenting bacterium or yeast as a chief material and
diluting it with water.
[0095] The lactic acid bacteria-containing beverage includes
fermented vegetable drinks, fermented fruit drinks, and fermented
soy milk drinks etc. Examples of items in the form of milk products
other than the beverage form includes products of the curd form
such as yogurt. The solid food form includes granules, powders
(inclusive of e.g. freeze-dried powders of fermented milk),
tablets, effervescent tablets, gums, gumdrops, and puddings
etc.
[0096] Processing into these forms can be carried out in the
conventional manner. Moreover, the carrier for use in the
processing into such forms may be any edible carrier. Particularly
preferred carriers are those having good mouth-feel and
taste-improving effects. Examples of such carriers having good
mouth-feel and taste-improving effects include artificial
sweeteners, sorbitol, xylitol, and so on. Other preferred carriers
are, for example, masking agents such as trehalose (product of
Hayashibara), cyclodextrin, Benekote BMI (product of Kao
Corporation), etc.
[0097] The lactic acid bacteria-containing beverage as a preferred
specific food form is described in detail below. Processing into
such a beverage can be carried out by the procedure which comprises
culturing the microorganism in a suitable fermentation material
containing nutrients for the microorganism, such as fluids derived
from vegetables or fruits, soy-milk (emulsified soy), etc. to
thereby cause fermentation of said material. The vegetables and
fruits for use as the fermentation material include cuttings,
crushings, grindings, squeezed-out juices, enzyme-treated products,
and dilutions or concentrates thereof. The vegetables include
pumpkins, carrots, tomatoes, sweet peppers, celery, spinach,
pigmented sweet potatoes, corn, beats, kale, parsley, cabbages, and
broccoli etc. The fruits include apples, peaches, bananas,
strawberries, grapes, water melons, oranges, and mandarin oranges
etc.
[0098] The cuttings, crushings, and grindings of vegetables and
fruits can be obtained by, for example, the procedure which
comprises washing the vegetable or fruit, subjecting it to a
blanching treatment, e.g. placing in hot water, where necessary,
and cutting, pulverizing or milling it by means of a crusher,
mixer, food processor, pulper finisher, Mycolloider, or the like.
Juices can be prepared by using a filter press, juicer-mixer, or
the like. Juices can also be prepared by filtering said grindings
(millings) through a filter cloth or the like. The enzyme-treated
products can be prepared by permitting cellulase, pectinase,
protopectinase or the like to act upon said cuttings, crushings,
grindings, or juices. The dilutions include 1 to 50-fold aqueous
dilutions. The concentrates include those concentrated 1 to
100-fold by such means as freeze concentration, concentration under
reduced pressure, etc.
[0099] Soy milk which is another specific example of the
fermentation substrate material can be prepared from soybean
materials in the routine manner. The soy milk includes a homogenate
prepared by immersing skinned soybeans in water, wet-pulverizing
these soybeans with a suitable mill or the like, and homogenizing
the pulverizate in the routine manner and a solution of
water-soluble soy protein in water etc.
[0100] The fermentation using a microorganism can be carried out by
inoculating said fermentation substrate material with the
microorganism of the invention and incubating the inoculated
material under stationary conditions. The medium may optionally be
supplemented with fermentation-promoting substances insuring good
growth of the microorganism used, for example various carbon
sources such as glucose, starch, sucrose, lactose, dextrin,
sorbitol, fructose, etc., nitrogen sources such as yeast extract,
peptone, etc., vitamins, and minerals.
[0101] The inoculum size of the microorganism should be generally
equivalent to a viable cell count of not less than about
1.times.10.sup.6 cells, preferably about 1.times.10.sup.7 cells per
cubic centimeter of the fermentation substrate fluid. As regards
cultural conditions, the fermentation temperature is generally
selected from the range of about 20-40.degree. C., preferably about
25-37.degree. C., more preferably 37.degree. C. and the
fermentation time is selected from the range of about 8-24
hours.
[0102] For stable fermentation, it is recommendable to prepare a
starter in advance and inoculate the fermentation substrate
material with the starter for fermentation. The representative
starter may for example be culture obtained by inoculating the
present strain of microorganism of the invention into said
fermentation substrate material subjected to usual sterilization at
90-121.degree. C. for 5-20 minutes beforehand, yeast
extract-supplemented 10% skim milk powder, or the like and
cultivating the microorganism under the same conditions as above.
The starter thus prepared usually contains about 10.sup.7-10.sup.9
cells of the microorganism of the invention per gram of the
culture.
[0103] The lactic acid fermentation product obtained in the above
manner may at times be a curd form (a yogurt-like or pudding-like
form) and such a product can be directly taken as a food. The
lactic acid fermentation product in said curd form can be further
homogenized to prepare the desired beverage form (for example, a
fermented soy milk beverage). This homogenization can be carried
out using an ordinary homogenizer. More particularly, it can be
carried out using Gaulin's high-pressure homogenizer [LAB 40] at
about 200-1000 kgf/cm.sup.2, preferably about 300-800 kfg/cm.sup.2,
or a Sanwa Machine Industry Co.'s homogenizer (article number:
HA.times.4571, H20-A2 etc.) at not less than 150 kg/cm.sup.2. By
this homogenization, a beverage product, particularly a fermented
soy milk beverage, which has an excellent palatability,
particularly a smooth mouth-feel, can be obtained. In carrying out
said homogenization, it is permissible, where necessary, to make
appropriate diluting, add an organic acid for pH adjustment, and/or
add various additives which are usually employed in the manufacture
of beverages, such as sugars, fruit juices, viscosity builders,
surfactants, and flavors, in suitable amounts. As a specific
preferred example of each kind of additive mentioned above and its
addition level (% by weight based on the weight of the curd-form
fermentation product) are: glucose 8% (% by weight, the same
applies hereinafter), sugar 8%, dextrin 8%, citric acid 0.1%,
glycerol fatty acid ester 0.2%, and flavor 0.1%.
[0104] Thus obtained lactic acid bacteria beverage of the invention
such as a fermented soy milk beverage can be aseptically dispensed
into suitable containers in the conventional manner to provide the
end-product. This product has a good palatability allowing smooth
swallowing and a good flavor.
[0105] The dosage (intake amount) of the above product can be
judiciously selected according to the age, sex, body weight, and
severity of illness of the recipient, among other variables, and is
not particularly restricted. Generally, 100-300 mL of a beverage
product with a viable cell count of 10.sup.8-10.sup.9 cells/mL can
be ingested per day.
[0106] A further specific example of the composition of the
invention in the food form is the effervescent tablet form. This
form can be prepared by formulating 10-35% (% by weight; the same
applies below) of sodium carbonate and/or sodium hydrogencarbonate
and 20-70% of a neutralizer, as effervescent ingredients, with
0.01-50% of the bacteria (lyophilized cells) of the invention. The
neutralizer to be used in this manner is an acidic compound capable
of neutralizing said sodium carbonate and/or sodium
hydrogencarbonate to generate carbon dioxide gas. Representative
examples of said neutralizer are organic acids such as L-tartaric
acid, citric acid, fumaric acid and ascorbic acid.
[0107] The amount of said effervescent ingredients in the
effervescent product of the invention is such that when this
product of the invention is dissolved in water, the solution shows
acidity, particularly an acidity of pH about 3.5-4.6. More
particularly, the amount can be selected from the range of 10-35%
sodium carbonate and/or sodium hydrogencarbonate and 20-70%
neutralizer. Particularly, the amount of sodium carbonate is
selected from the range of 11-31%, preferably 22-26%; sodium
hydrogencarbonate from the range of 10-35%, preferably 20-30%.
Among these alternative choices, it is most preferable to use
sodium hydrogencarbonate alone within the range of 20-25%. The
amount of the neutralizer is selected from the range of 20-70%,
preferably 30-40%. In particular, it is most preferable to use
L-tartaric acid within the range of 20-25% and ascorbic acid within
the range of 8-15%.
[0108] The effervescent product contains the microorganisms of the
invention and the effervescent ingredients as essential components
and may optionally be contained suitable amounts of various known
additives such as the excipient, binder, disintegrator, lubricant,
viscosity builder, surfactant, osmolarity modulating agent,
electrolyte, sweetener, flavor, colorant, pH control agent, and so
forth. Examples of the additives are starches such as wheat starch,
potato starch, corn starch, dextrin, etc.; saccharides such as
sucrose, glucose, fructose, maltose, xylose, lactose, etc.; sugar
alcohols such as sorbitol, mannitol, maltitol, xylitol, etc.; sugar
rearrangement glycosides such as coupling sugar, palatinose, etc.;
excipients such as calcium phosphate, calcium sulfate, etc.;
binders/thickeners such as starches, saccharides, gelatin, gum
Arabic, dextrin, methylcellulose, polyvinylpyrrolidone, polyvinyl
alcohol, hydroxypropylcellulose, gum xanthan, pectin, gum
tragacanth, casein, alginic acid, etc.; lubricants such as leucine,
isoleucine, L-valine, sugar esters, hydrogenated oils, stearic
acid, magnesium stearate, talc, macrogols, etc.; disintegrators
such as crystalline cellulose (Avicel, Asahi Chemical Industry Co.,
Ltd.), carboxymethylcellulose (CMC), carboxymethylcellulose sodium
(CMC-Na), carboxymethylcellulose calcium (CMC-Ca), etc.;
surfactants such as polyoxyethylene sorbitan fatty acid ester
(polysorbate), lecithin, etc.; dipeptides such as aspartame,
alitame, etc.; and sweeteners such as stevia, saccharin, and so
forth. These can be judiciously selected and used in suitable
amounts taking into consideration the relationship of each to the
essential components, the proportion of the preparation, and method
of production of the preparation, among other factors.
[0109] Furthermore, in the effervescent preparation of the
invention, vitamins, particularly cyanocobalamine and ascorbic acid
(vitamin C), can be formulated in suitable amounts. The amount is
not particularly restricted but usually vitamin C, for instance,
may be added up to 30% at the maximum, preferably within the range
of about 5-25%.
[0110] The method of producing the effervescent preparation of the
invention can be fundamentally similar to the conventional method
for production of effervescent tables of this kind. Thus, the
preparation of the invention in the effervescent tablet form can be
prepared by weighing out predetermined amounts of the respective
ingredients, mixing them, and processing the whole by the direct
powder compression method or the dry or wet granulation-compression
method, for instance.
[0111] The preparation of the invention, thus obtained, can be
converted to a beverage form suitable for oral administration by
mere placing in water and be administered orally.
[0112] The dosage (intake amount) thereof can be judiciously
established according to the age, sex, body weight, severity of
illness of the recipient, among other variables, and is not
particularly restricted but generally 1-2 tablets of the
effervescent tablet form of the invention weighing about 1.5-6.0 g
per tablet can be dissolved in 100-300 mL of water and caused to be
ingested per dose.
[0113] The particularly preferred blending proportions of the
substrate daidzein compound or daidzein compound-containing
ingredient, the particular lactic acid bacterial strain, and
optionally formulated other ingredients in the composition of the
invention, per 100 g of the composition, are: the daidzein compound
or daidzein compound-containing ingredient within the range of
about 10-50 mg calculated as daidzein, the number of the lactic
acid bacterial strain within the range of 10.sup.9-10.sup.10 cells
(viable cell count), and oligosaccharides and others within the
range of about 1-5 g.
[0114] Since the equol-producing lactic acid bacteria-containing
composition of the invention is designed to contain a microorganism
(primarily live bacteria) as mentioned hereinbefore, such
conditions as the application of heat and pressure are not
recommendable in the processing of the composition into end
products. Therefore, in processing the composition of the invention
into such product forms as bars, granules, powders, and tablets, it
is preferable to directly formulate the microorganism in the form
of lyophilized cells or use lyophilized cells treated with a
suitable coating agent.
[0115] However, the equol-producing lactic acid bacteria-containing
composition of the invention need not essentially contain viable
bacteria. When said composition comprising viable bacteria and said
daidzein compound or the like which said bacteria may utilize
contains bacteria-produced equol, it may be subjected to a routine
heat sterilization to kill the bacteria. Such a heat sterilization
given to the composition inhibits taste and flavor deteriorations
caused by excessive fermentation of the viable bacteria formulated
in the composition during storage or distribution on the
market.
(3-5) Pharmaceutical Product Forms
[0116] The equol-producing lactic acid bacteria-containing
composition of the invention can be processed into pharmaceutical
preparations generally containing said defined lactic acid
bacterial strain as an essential component together with a suitable
pharmaceutically acceptable carrier.
[0117] The carrier includes various diluents and excipients, such
as fillers, volume builders, binders, humectants, disintegrators,
surfactants, lubricants, etc. which are known to be used in the
art. These can be selectively used according to the unit dosage
form of the preparation.
[0118] As the unit dosage form of the pharmaceutical preparation, a
variety of forms can be selectively used. The representative forms
are tablets, pills, powders, solutions, suspensions, emulsions,
granules, capsules, and suppositories.
[0119] The carrier which can be used in the processing into the
tablet form includes various excipients such as lactose, sucrose,
sodium chloride, glucose, urea, starch, calcium carbonate, kaolin,
crystalline cellulose, silicic acid, potassium phosphate, etc.;
binders such as water, ethanol, propanol, simple syrup, glucose
solution, starch solution, gelatin solution,
carboxymethylcellulose, hydroxypropylcellulose, methylcellulose,
polyvinylpyrrolidone, etc.; disintegrators such as
carboxymethylcellulose sodium, carboxymethylcellulose calcium,
low-substituted hydroxypropylcellulose, dry starch, sodium
alginate, agar powder, laminaran powder, sodium hydrogencarbonate,
calcium carbonate, etc.; surfactants such as
polyoxyethylene-sorbitan fatty acid esters, sodium lauryl sulfate,
stearic acid monoglyceride, etc.; disintegration inhibitors such as
sucrose, stearin, hydrogenated cacao butter, hydrogenated oils,
etc.; absorption promoters such as quaternary ammonium bases,
sodium lauryl sulfate, etc.; humectants such as glycerol, starch,
etc.; adsorbents such as starch, lactose, kaolin, bentonite,
colloidal silica, etc.; and lubricants such as purified talc,
stearates, boric acid powder, polyethylene glycol, and so
forth.
[0120] Furthermore, where necessary, tablets may be prepared in the
forms having the conventional coatings such as sugar-coated
tablets, gelatin-coated tablets, enteric-coated tablets,
film-coated tablets, etc., or in the form of double-layered tablets
or multi-layered tablets.
[0121] The carrier which can be used in the formation of pills
includes various excipients such as glucose, lactose, starch, cacao
butter, hydrogenated vegetable oils, kaolin, talc, etc.; binders
such as gum Arabic powder, gum tragacanth powder, gelatin, ethanol,
etc.; and disintegrators such as laminaran, agar, and so forth.
[0122] The carrier which can be used in the formation of
suppositories includes polyethylene glycol, cacao butter, higher
alcohols, higher alcohol esters, gelatin, and semi-synthetic
glycerides etc. The encapsulated product can be manufactured
generally by blending the bacteria of the invention with various
kinds of pharmaceutical carriers such as those mentioned above and
filling the mixture into hard capsule shells or soft elastic
capsule shells in the conventional manner.
[0123] Furthermore, where necessary, colorant, preservative,
flavoring, corrigent, sweetener, and other drugs can be
incorporated into the pharmaceutical product of the invention.
[0124] The quantity of the microorganism of the invention to be
incorporated in the prepararion of the invention is not
particularly restricted but can be judiciously selected from a
broad range. The generally recommended proportion is about
10.sup.8-10.sup.10 cells/g of the pharmaceutical preparation.
[0125] The method of administration of the above pharmaceutical
preparation is not particularly restricted but can be established
according to the preparation forms, various patient factors such as
age, sex, etc. and the severity of illness. For example, the
tablets, pills, solutions, suspensions, emulsions, granules, and
capsules are administered orally and the suppositories are
administered rectally.
[0126] The dosage of said pharmaceutical preparation can be
judiciously established according to the method of administration,
the patient's age, sex and other factors, and the severity of
illness but is preferably about 0.5-20 mg/day in terms of the
microorganism of the invention, i.e. active ingredient, per kg body
weight. This preparation can be administered in 1-4 divided doses a
day.
[0127] On ingestion (administration) of the composition of the
invention, the microorganism in the composition finds its way alive
into the lower digestive tract or settles there as part of the
intestinal flora, whereby the expected efficacy is expressed. In
this connection, the particularly preferred preparation form is the
enteric-coated tablet, with which the microorganism can be
transported to the intestines without being attacked by gastric
acid.
[0128] The equol-producing lactic acid bacteria-containing
composition of the invention as obtained in the above manner is
useful for the symptomatic prophylaxis and treatment of malaise
and/or postmenopausal osteoporosis and climacteric disturbances in
middle-aged and elderly women. Such prophylaxis and treatment can
be accomplished by administering an effective amount of said
composition of the invention to the middle-aged or elderly woman
for whom it is required or causing them to ingest the same. The
effective amount mentioned just above is not particularly
restricted insofar as it is sufficient to prevent and control the
various manifestations of osteoporosis and climacteric disturbances
accompanying malaise and/or menopause in middle-aged and elderly
women. As a rule of thumb, however, the dosage can be generally
selected so that the amount of equol excreted in the urine of the
person who has taken the composition of the invention reaches at
least 5 .mu.mole (about 1.2 mg)/day.
BRIEF DESCRIPTION OF THE DRAWINGS
[0129] FIG. 1 is a diagrammatic representation showing the
relationship of incubation time to viable cell count as determined
by the test protocol described in Test Example 1.
[0130] FIG. 2 is a diagrammatic representation showing the
relationship of incubation time to equol-producing ability (score)
as determined by the test protocol described in Test Example 1.
[0131] FIG. 3 is a diagrammatic representation showing the
relationship of incubation time to equol output as determined by
the test protocol described in Test Example 1.
[0132] FIG. 4 is a diagrammatic representation showing the time
course of concentration of each of daidzein compounds and equol in
the culture as monitored in accordance with the protocol described
in Test Example 2.
[0133] FIG. 5 is a diagrammatic representation showing the
relationship of storage period to equol-producing ability (score)
as determined in accordance with the test protocol described in
Test Example 3.
[0134] FIG. 6 is a diagrammatic representation showing the
incubation time-dependent behaviors of the equol-producing strain
(changes in growth performance, equol-producing ability, and equol
output) as determined by the experiment described in Test Example
1-3.
[0135] FIG. 7 is a diagrammatic representation showing the
relationship of incubation time to viable cell count as determined
by the test protocol described in Test Example 4.
BEST MODE FOR CARRYING OUT THE INVENTION
[0136] The following examples of production of the equol-producing
lactic acid bacteria-containing composition of the invention are
intended to describe the present invention in further detail and
should by no means be construed as defining the invention.
Example 1
(1) Production of a Fermented Soy Milk Beverage
[0137] The following ingredients were taken according to the
formula and blended to prepare the composition of the invention in
the form of a fermented soy milk beverage.
TABLE-US-00003 Fermentation culture of 100 mL water-soluble soy
protein Vitamins & minerals q.s. Flavoring q.s. Water q.s Total
150 mL
[0138] The above fermentative culture of water-soluble soy protein
was obtained by dissolving 13 g of water-soluble soy protein in 100
ml of water, adding 10.sup.8-10.sup.9 cells of Lactococcus 20-92
(FERM BP-10036), and carrying out fermentation at 37.degree. C. for
24-48 hours. The water-soluble soy protein used contained about 1-2
mg, calculated as daidzein, of daidzein compounds in each one
gram.
(2) Production of a Fermented Milk
[0139] The following ingredients were taken according to the
formula and blended to prepare the composition of the invention in
a fermented milk form.
TABLE-US-00004 Lactococcus 20-92 fermented milk 100 mL Vitamins
& minerals q.s. Flavoring q.s. Water q.s. Total 150 mL
[0140] The Lactococcus 20-92 fermented milk was obtained by adding
10.sup.8-10.sup.9 cells of Lactococcus 20-92 (FERM BP-10036) to 1L
of cow's milk (having a nonfat milk solids content of 8.5% or
greater and a milk fat content of 3.8% or greater) and carrying out
fermentation at 37.degree. C. for 24-48 hours.
(3) Production of a Freeze-Dried Powder of Fermented Soy Milk
[0141] Using about 10.sup.9 cells of Lactococcus 20-92 (FERM
BP-10036) and 100 g of soy milk (soy solids 10%, daidzein compound
content 10-15 mg calculated as daidzein), lactic acid fermentation
was carried out at 37.degree. C. for 72-96 hours for the production
of equol. This fermentation product was freeze-dried to prepare a
powder. The equol content of the powder as determined by HPLC was
0.1-0.3 weight %.
[0142] The powder obtained above and various other ingredients were
weighed out according to the following formula and blended to
prepare the composition of the invention in the powder form (food
form and pharmaceutical product form).
TABLE-US-00005 Freeze-dried powder of fermented soy milk 2.2 g
(equol content 0.005 g) Excipient (corn starch) 17 g Vitamins &
minerals q.s. Flavoring q.s. Total 20 g
(4) Production of a Powder
[0143] The following ingredients were weighed out according to the
formula and blended to prepare the composition of the invention in
a powder form (food form and pharmaceutical product form).
TABLE-US-00006 Freeze-dried powder of Lactococcus 20-92 4.1 g
Excipient (lactose) 1.0 g Vitamins & minerals q.s. Flavoring
q.s. Total 20 g
[0144] A freeze-dried powder of Lactococcus 20-92 was obtained by
culturing Lactococcus 20-92 (FERM BP-10036) in a suitable liquid
growth medium (MRS) (37.degree. C., 24-48 hrs), harvesting and
suspending grown cells in 10% skim milk, and lyophilizing the
suspension. The cell content of the powder was 10.sup.9-10.sup.10
cells/g.
[0145] The above powder may be made into a daidzein-containing
powder by blending it further with 4.1 g of semi-purified soy
isoflavine powder.
[0146] Intake of the daidzein-containing powder thus obtained
results in the urinary equol excretions of about 5 .mu.moles (about
1.2 mg) per day, indicating clearly that the amount of equol
corresponding to the above excretions can be produced in vivo.
(5) Production of Granules
[0147] The following ingredients were weighed out according to the
formula and blended to prepare the composition of the invention in
a granular form (food form and pharmaceutical product form).
TABLE-US-00007 Semi-purified soy isoflavone powder 4.1 g
Freeze-dried powder of Lactococcus 20-92 1.0 g Sucrose acid ester
q.s. Vitamins & minerals q.s. Flavoring q.s. Total 20 g
[0148] The freeze-dried powder of Lactococcus 20-92 used was the
same as the one used above in (1).
[0149] Intake of the above composition results in the concurrent
delivery of daidzein and equol-producing bacteria to the large
intestine, thus enabling production of equol in the large
intestine.
[0150] Test Examples relating to the equol-producing lactic acid
bacterial strain of the invention are presented below.
Test Example 1
Test for Growth Performance, Equol-Producing Ability (Activity),
and Equol Output
(1) Test Protocol
[0151] Lactococcus 20-92 (10.sup.7-10.sup.9 cells/g) was incubated
in 5 mL of BHI broth [a liquid medium for growth (basal medium)]
anaerobically at 37.degree. C. for 24 hours and the culture was
diluted to 10.sup.2 and 10.sup.4 cells with the basal medium.
[0152] The culture obtained at completion of incubation and its
dilutions prepared above were respectively taken, 0.2 mL each, and
blended with 5 mL each of daidzein-supplemented basal medium
(daidzein added to BHI broth at a final concentration of 10
.mu.g/mL), cow's milk and soy milk, respectively, and cultured
anaerobically at 37.degree. C. The incubation time was set to 8,
24, 48, 72, and 96 hours in the case of 10 .mu.g/mL
daidzein-supplemented basal medium and soy milk, and 8, 24 and 48
hours in the case of cow's milk.
[0153] Before the start of incubation and at the end of each
incubation period, 0.1 mL and 0.2 mL portions of the culture were
sampled and respectively subjected to the counting of cells and
assay of equol-producing ability (activity). Furthermore, for 10
.mu.g/mL daidzein-containing basal medium and soy milk, 0.5 mL of
each culture was sampled before the start of incubation and at the
end of each incubation period and the amount of equol produced in
each sample was determined.
[0154] The number of bacteria was determined in the following
manner. Each 0.1 mL sample was diluted with PBS(-) (product of
Nissui Co.) to prepare 10.sup.4, 10.sup.5, 10.sup.6 and
10.sup.7-fold dilutions and 0.1 mL each of these dilutions were
respectively coated on GAM agar medium and incubated aerobically at
37.degree. C. for 24 hours. The colonies formed on the medium were
counted for use as the number of bacteria.
[0155] The equol-producing ability (activity) was assayed as
follows. Each 0.2 mL sample was blended with 5 mL of
daidzein-supplemented basal medium (each in triplicate) and
incubated anaerobically at 37.degree. C. for 96 hours. At
completion of incubation, 0.5 mL samples of the respective cultures
were taken and respectively extracted twice with 5 mL portions of
ethyl acetate and the daidzein, dihydrodaidzein (intermediate), and
equol in the extract were quantitated by HPLC. Moreover, based on
the total amount, the percentage of equol was calculated. The
results were scored on the following 5-point scale and the average
score of 3 samples was used as an index of equol-producing ability
(activity). [0156] 4: Equol (90% or greater) [0157] 3: Equol
produced, with daidzein diminishing to less than 50% (formation of
intermediate) [0158] 2: Equol produced, residual daidzein (50% or
greater) (formation of intermediate) [0159] 1: Intermediate formed,
equol not produced [0160] 0: Neither intermediate nor equol
produced, with daidzein not diminishing
[0161] The amount of equol produced was determined as follows. Each
0.5 mL sample was extracted twice with 5 mL portions of ethyl
acetate and the amounts of daidzein, dihydrodaidzein
(intermediate), and equol in the extract were quantitated by HPLC.
Then, the respective concentrations were used to calculate the
amount of equol produced.
(2) Test Results
(2-1) The Results of Counting of the Cells (Growth Performance) are
Presented in FIG. 1.
[0162] In the diagrammatic representation, (1) represents the
result obtained in the case where the daidzein-supplemented basal
medium was used, (2) represents the result obtained in the case
where soy milk was used, and (3) represents the result obtained
when cow's milk was used. In each diagram, the horizontal axis
represents incubation time (hr) and the vetical axis represents
viable cell count (Log CFU/mL).
[0163] It can be seen from the respective diagrams, the growth
performance of the strain of the invention is good and, regardless
of the inoculum size used, the stationary phase of growth was
invariably attained in 8 hours of incubation in all the
daidzein-supplemented basal medium, soy milk and cow's milk. The
viable cell count was found to be steady at 10.sup.9.1-9.4 CFU/mL
in the daidzein-supplemented basal medium, 10.sup.8.5-8.7 CFU/mL in
soy milk, and 10.sup.8.0-8.4 CFU/mL in cow's milk.
(2-2) The Equol-Producing Ability (Activity) Values Found are
Presented in FIG. 2.
[0164] In FIG. 2, (1) represents the result obtained in the case
where the daidzein-supplemented basal medium was used, (2)
represents the result obtained in the case where soy milk was used,
and (3) represents the result obtained in the case where cow's milk
was used. In each diagram, the horizontal axis represents
incubation time (hr) and the vetical axis represents activity
score.
[0165] It is obvious from the results presented in FIG. 2 that the
equol-producing ability (activity) tends to increase with time in
any of the daidzein-supplemented basal medium, soy milk, and cow's
milk. It could also be confirmed that even in the cases where cow's
milk and soy milk were used, the equol-producing ability (activity)
of the strain of the invention is sustained.
(2-3) Results of the Amount of Equol Produced Determination
[0166] The quantities of equol produced in the
daidzein-supplemented basal medium and soy milk (about 80 .mu.g/mL
calculated as daidzein) were as shown in FIG. 3.
[0167] Referring to FIG. 3, (1) represents the result obtained in
the case where the daidzein-supplemented basal medium was used and
(2) represents the result obtained in the case where soy milk was
used. In each diagram, the horizontal axis represents incubation
time (hr) and the vetical axis represents equol concentration
(.mu.g/mL).
[0168] In both media, the production of equol began to be noticed
at hour-48 following the start of incubation. In the case where soy
milk was used, the amount of equol produced varied with inoculum
size and particularly at the inoculation level of 4.00%, the
production of equol was as large as 57.0 .mu.g/mL at hour-96 of
incubation.
[0169] Although, in soy milk, not less than 90% of daidzein serving
as the precursor of equol is present in the form of glycoside (in
the form of glucose attached), the peak corresponding to the
glycoside was no longer observed on the post-incubation
chromatogram and this fact suggests that the strain of the
invention decomposes the glycoside (.beta.-glucosidase activity) to
give daidzein and further metabolizes this daidzein to equol.
Test Example 2
Equol Production Pathway in Lactococcus 20-92
(1) Test Protocol
[0170] Lactococcus 20-92 (10.sup.7 cells/mL) was aerobically
cultured in 5 mL of BHI broth (a liquid medium for growth, basal
medium) at 37.degree. C. for 24 hours and 0.2 mL of the resulting
culture was blended with 5 mL of daidzein-supplemented basal medium
and the mixture was incubated anaerobically at 37.degree. C. The
incubation time was set to 8 hr, 24 hr, 30 hr, 36 hr, 48 hr, 51 hr,
54 hr, 60 hr, 84 hr, and 96 hr.
[0171] Before the start of incubation and at the end of each
incubation period, 0.5 mL samples were taken and the concentrations
of daidzein, dihydrodaidzein (intermediate), and equol in each
sample were determined.
(2) Results
[0172] The results obtained are presented in FIG. 4.
[0173] FIG. 4 is a diagrammatic representation of the changes with
time in the concentrations of daidzein (left), dihydrodaidzein
(center), and equol (right). In each diagram, the horizontal axis
represents incubation time (hr) and the vetical axis represents the
concentration (.mu.g/mL) of the corresponding substance.
[0174] It will be apparent from the data presented in FIG. 4 that
the concentration of daidzein began to decline at hour-48 of
incubation, the intermediate compound dihydrodaidzein was formed
during the period from hour-48 to hour-60, and the production of
equol began at hour-48. It can also be confirmed that the
metabolism of daidzein to equol had substantially gone to
completion by hour-60.
[0175] While the above results indicated that the metabolism from
daidzein to equol occurred via said intermediate compound
dihydrodaidzein, the results also suggested that the formation of
dihydrodaidzein and the metabolism thereof to equol took place in
parallel.
Test Example 3
Low-Temperature Stability of Lactococcus 20-92 Strain-Containing
Fermented Milks
(1) Test Protocol
[0176] Lactococcus 20-92 was cultured in 5 mL of a liquid medium
for growth (basal medium) anaerobically at 37.degree. C. for 24
hours, the resulting culture was used to inoculate 1L and 2L of
cow's milk and 1L of commercial skim milk (10% solids),
respectively, at the level of 4% and cultured aerobically under
stationary conditions at 37.degree. C. for 48 hours. The cultures
were stored at 4.degree. C.
[0177] In the case of cow's milk, the equol-producing ability
(activity) was monitored on a weekly basis following completion of
culture through week 4 of low-temperature storage at 4.degree. C.
Furthermore, two of the tubes were reserved and stored till day-42
and day-51, respectively, and the activity was determined in each
case.
[0178] In the case of skim milk, the activity was determined at
completion of culture and at week-1 and day-34 of low-temperature
storage at 4.degree. C.
[0179] The activity scores before storage and at the end of each
storage period were generated by the above-described method
comprising inoculating 5 mL of 10 .mu.g/mL daidzein-supplemented
basal medium at the level of 4% (0.2 mL) in triplicate, culturing
the microorganism anaerobically at 37.degree. C. for 96 hours, and
determining the concentrations of daidzein, dihydrodaidzein
(intermediate), and equol for activity scoring.
(2) Results
[0180] The results are presented in FIG. 5. In FIG. 5, the
horizontal axis represents storage period (days) and the vetical
axis represents activity score.
[0181] It is apparent from this diagrammatic representation of
results that, as far as cow' milk is concerned, the equol-producing
ability (activity) is sustained to week-4 of low-temperature
storage at 4.degree. C. after completion of culture in both cases
of 1L and 2L. Moreover, in the case of 2L of cow's milk, the
activity was found to be sustained to day-51, that was the last day
of monitoring of the storage stability at 4.degree. C. In the case
of 1L of commercial skim milk, too, the equol-producing ability
(activity) was apparently sustained to day-34, the last day of
monitoring of the low-temperature storage stability at 4.degree. C.
after completion of culture.
[0182] The foregoing results indicate that the fermented milk
prepared by using Lactococcus 20-92 is capable of retaining the
activity even under low-temperature storage conditions and,
therefore, is also suitable for food distribution.
[0183] The relationship of the growth performance of Lactococcus
20-92 to its equol-producing ability (activity) and the amount of
equol produced as deducible from the results obtained in the above
Test Examples 1-3 can be diagrammatically represented as shown in
FIG. 6.
[0184] Thus, although cultural conditions varied with different
culture media, the equol-producing ability (activity) can be
maintained in both the growth phase and the stationary phase. On
the other hand, with regard of equol output, it appears that the
enzyme begins to be expressed or activated to produce equol after a
certain lag time in the stationary phase.
Test Example 4
[0185] Gastric Juice Tolerance Test of the Fermented Milk Prepared
by using Lactococcus 20-92
(1) Test Protocol
[0186] Lactococcus 20-92 was anaerobically cultured in 5 mL of a
liquid medium for anaerobic growth (BHI broth, basal medium) at
37.degree. C. for 24 hours. The resulting culture (10.sup.9
cells/g) was used to inoculate 1L of cow's milk at the 4% level and
incubated aerobically under stationary conditions at 37.degree. C.
for 48 hours. After completion of culture, the milk was stored at
4.degree. C. and, regarding it as fermented milk, was subjected to
the following test.
[0187] As artificial gastric juices, 0.045% pepsin-supplemented 50
mM glycine-HCl buffers (pH 2.5 and pH 3.0) were prepared. As
control, 50 mM glycine-HCl buffer (pH 6.0) was prepared.
[0188] To 9 mL of each artificial gastric juice, 1 mL of the
fermented milk stored at low temperature was added and the mixture
was incubated (cultured) aerobically under stationary conditions in
an incubator at 37.degree. C.
[0189] The incubation time was set to 1 hr, 2 hr, and 3 hr, and 0.1
mL and 0.2 mL aliquots of each culture were respectively sampled
before the start of incubation and at the end of each incubation
period and subjected to the determination of viable cell count (in
the case of 0.1 mL) and equol-producing ability (activity) (in the
case of 0.2 mL).
[0190] The determination of viable cell count was carried out in
accordance with the procedure described above in Test Example
1-(1), which comprises sampling 0.1 mL of each culture, diluting
the sample 10.sup.4, 10.sup.5, 10.sup.6 and 10.sup.7-fold with
Nissui's PBS(-), coating 0.1 mL of each dilution on GAM agar
medium, incubating the inoculated medium aerobically at 37.degree.
C. for 24 hours, and counting the colonies formed on the GAM
agar.
[0191] The determination of equol-producing ability (activity) was
carried out in accordance with the procedure described above in
Test Example 1-(1), which comprises inoculating 5 mL of
daidzein-supplemented basal medium with 0.2 mL (4%) of the sample
(in triplicate), incubating the inoculated medium anaerobically at
37.degree. C. for 96 hours, and measuring the concentrations of
daidzein, dihydrodaidzein (intermediate), and equol in the medium
for activity scoring.
(2) Results
[0192] The results obtained are presented in FIG. 7-A (viable cell
count) and B (equol concentration).
[0193] In FIG. 7-A, the horizontal axis represents incubation time
(hr) and the vetical axis represents viable cell count (Log CFU/ml
in milk).
[0194] In FIG. 7-B, the horizontal axis represents incubation time
(hr) and the vetical axis represents equol activity (score).
[0195] The following can be deduced from the results presented in
FIGS. 7-A and 7-B. Thus, in the buffer solution at pH 6.0, the
viable cell count was sustained at the 10.sup.8 cells/mL level up
to hour-3, and, here, the equol-producing ability (activity) was
also sustained. In the artificial gastric juice at pH 3.0, the
viable cell count was sustained up to hour-3 of incubation and,
here, the activity was also sustained. On the other hand, in the
artificial gastric juice at pH 2.5, a marked decrease in viable
cell count began to take place at hour-2 of incubation and the
activity also disappeared.
[0196] When studied in the same test system as above, the
probiotics (microorganisms which find their way alive into the
intestinal canal and exhibit physiological activity there) on the
market are reportedly unchanged in viable cell count at pH 3.0 but
decreased significantly at pH 2.5. This means that the tolerance to
gastric juice at pH 3.0 allows these microorganisms to pass through
the stomach alive. Therefore, the fermented milk prepared by using
Lactococcus 20-92 is reasonably expected to deliver the organisms
alive to the intestines to let them exhibit sustained activity in
the lower part of the small intestine and in the large
intestine.
Test Example 5
Bile Tolerance Test of Lactococcus 20-92
[0197] The tolerance to bile was determined with VITEK GPI Card
(Nippon Biomerieux Co., Ltd) and evaluated by using the growth
performances of the strain of the invention in 10% and 40% biles as
indicators.
(1) Test Protocol
[0198] Lactococcus 20-92 (10.sup.8-9 cells) was smeared on 5% sheep
blood-supplemented Trypticase-Soy agar and aerobically cultured at
37.degree. C. for 24 hours. The colonies on the medium at
completion of culture were hooked with a platinum loop and a
homogeneous suspension thereof in 0.5% sterile saline was prepared.
This suspension was placed in VITEK GPI Card and, after 15 hours'
incubation at 35.degree. C., the growth performance of the strain
in the presence of bile was evaluated by using the dye (pH
indicator). The bile was prepared by dissolving a predetermined
amount of bile powder in sterile distilled water and placed in the
Card in advance.
(2) Results
[0199] The results of the above test indicate that Lactococcus
20-92 grows in 10% and 40% biles, showing tolerance to 40%
bile.
Test Example 6
Hemolysis Test of Lactococcus 20-92
(1) Test Protocol
[0200] Lactococcus 20-92 (10.sup.8-9 cells) was smeared on 5% sheep
blood-supplemented Trypticase Soy agar and cultured anaerobically
(N.sub.2:CO.sub.2:H.sub.2=8:1:1) at 37.degree. C. for 24-48 hours.
The portion around the colony formed on the medium after completion
of culture was observed, and the hemolytic potential was evaluated
according to the extent of decomposition of blood components
(depigmentation or discoloration).
(2) Results
[0201] As the result of the above test, depigmentation (appearance
of a transparent, colorless zone) was not observed around the
colony, indicating that Lactococcus 20-92 does not cause
.beta.-hemolysis and, in this respect, is a safe microorganism.
Test Example 7
Cell-Infiltrating Enzyme Activity Test of Lactococcus 20-92
[0202] Regarding the systemic invasion of ingested lactic acid
bacteria, a depression in the defensive function of the mesenterium
or impairment of the mesenterium itself may be considered as the
factor on the host side. As the factor on the side of bacteria,
their enzymatic activity (cell-infiltrating enzymes) decomposing
the lipid-protein complex proteoglycans constituting the
mesenterium can be mentioned.
[0203] This test was intended to investigate whether Lactococcus
20-92 has cell-infiltrating enzyme activities, namely collagenase
(gelatinase), hyaluronidase and sialidase (neuraminidase)
activities, or not and was carried out in the following manner.
(1) Test Protocol
[0204] Lactococcus 20-92 was smeared (smear size: 10.sup.8-9 cells)
on blood-supplemented agar medium and cultured anaerobically
(N.sub.2:CO.sub.2:H.sub.2=8:1:1) at 37.degree. C. for 24-48
hours.
[0205] The colonies on the medium after culture were hooked up with
a platinum loop and suspended in sterile distilled water to prepare
a homogeneous suspension. Using this suspension, the presence or
absence of collagenase (gelatinase) was investigated with Api.TM.
(Nippon Biomerieux Co., Ltd.) using the degradation of gelatin as
the indicator.
[0206] Moreover, the test as to whether Lactococcus 20-92 has
hyaluronidase and sialidase (neuraminidase) activities or not was
carried out by the procedure comprising incubating Lactococcus
20-92 in Tris-HCl buffer solution (pH 7.0) containing hyaluronic
acid or sialic acid as the substrate (37.degree. C., aerobic, 15
min. for sialidase activity and 24 hr for hyaluronidase activity)
and measuring the degrees of decrease in the concentrations of the
respective substrates.
(2) Results
[0207] Lactococcus 20-92 showed none of collagenase (gelatinase),
hyaluronidase, and sialidase (neuraminidase) activities.
[0208] Thus, in view of the fact that the strain of the invention
lacks cell-infiltrating enzymes which constitute a factor in
infectivity, the strain was confirmed to be a highly safe
microorganism from infectivity points of view as well.
Test Example 8
Vancomycin Resistance Test
[0209] The acquisition of resistance to antibiotics (mutation) by
bacteria has been a matter of serious concern in recent years. It
is not rare that patients infected with bacteria which have
acquired such resistance to antibiotics succumb to death because
they do not respond to the antibiotics. Particularly, the emergence
of vancomycin-resistant bacteria (VRE) is a matter of serious
concern in the field of clinical medicine today. Moreover, there is
the apprehension that if the ingested organisms harboring the
vancomycin resistance gene reach and settle in the intestines where
they come into contact with virulent or infectious microorganisms
(pathogenic bacteria), the vancomycin resistance gene may be
transferred to the pathogenic bacteria, with the result that these
bacteria also acquire vancomycin resistance. Therefore, it is
necessary, at least, that microorganisms which are used as
probiotics should not be vancomycin-resistant organisms.
[0210] This test was intended to investigate the susceptibility of
Lactococcus 20-92 to vancomycin and was performed as follows.
(1) Test Protocol
[0211] The vancomycin susceptibility test was performed using
Sensi-Disk (product of Nippon Becton-Dickinson Company, Ltd.).
Lactococcus 20-92 was smeared (smear size: 10.sup.8-9 cells) on GAM
agar medium, a disk containing 30 .mu.g of vancomycin was placed on
the medium, and an aerobic culture was carried out at 37.degree. C.
for 24 hours. After the above incubation time, the diameter of the
inhibition zone formed around the disk was measured and evaluated
according to the evaluation table.
(2) Results
[0212] The diameter of the inhibition zone for Lactococcus 20-92
was 11.9.+-.0.2 mm and the susceptibility evaluation according to
the evaluation table was positive (susceptible: .gtoreq.10 mm).
This result indicated that the strain of the invention is not a
vancomycin-resistant strain and, therefore, is considered safe.
[0213] Presented in Example 2 below is an example of the production
of equol from daidzein by using the lactic acid bacterial strain of
the invention.
Example 2
Production of Equol
[0214] One mL of suspension containing 10.sup.7-10.sup.9 cells of
Lactococcus 20-92 (FERM BP-10036) in GAM medium for culture of
anerobic bacteria was prepared and this suspension was added to 100
g of soy milk (solids concentration: ca 2.2%). The mixture was
incubated anaerobically at 37.degree. C. for 72-96 hours and the
equol produced in the culture was monitored by HPLC. The daidzein
compound content of said soy milk was 95 .mu.g/mL calculated as
daidzein.
[0215] The result indicated the formation of 10.7.+-.6.3 .mu.g/mL
(mean.+-.standard deviation of 3 experiments) of equol in the above
soy milk culture.
[0216] The above finding shows clearly that by exploiting the
microorganism of the invention, equol can be produced from the
daidzein compounds contained in food materials with good efficiency
and at low cost.
* * * * *